The URL can be used to link to this page

Browse Search

Home My WebLink About20222370.tiffMariah Higgins From: Sent: To: Subject: Attachments: Follow Up Flag: Flag Status: Kyle Regan <kyle@civilresources.com> Tuesday, December 20, 2022 11:15 AM Mariah Higgins RE: Red Tierra Equities LLC - Section 20 DRMS 112 File No. M-2022-001 Adequacy 7 Stitched.pdf Follow up Flagged Caution: This email originated from outside of Weld County Government. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi Mariah, Please see the attached Adequacy Review 7 Response for the Red Tierra Equities Section 20 DRMS Permit Application to be added to the documents for public review. Please send confirmation of receipt. Thanks! Kyle Regan (m) 408.930.2544 Robl:c Rev;ec4 (/� (/► (/ 1 D ( (/� I `\/ CC se PL(tP/MN/oA/icofDA) • IA,*HfFR/cy' °I /0 14 /2 3 '2 /ASS /a X 2022- 23 70 CIVIL RES"URCES,LLC ENGINEERS & PLANNERS December 20., 2022 Mr. Peter Hays Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 RE: Red Tierra Equities, L.L.C., Section 20 Mine, File No. M-2022-001, 112c Permit Application Adequacy Review 7 Response Dear Mr. Hays: This letter addresses the Adequacy Review letter dated December 18th, 2022 regarding the Section 20 Gravel Mine 112 Construction Materials Reclamation Permit Application Package. Responses to your comments follow in bold: Groundwater Model 1. In response to Item #3, the Applicant stated the Groundwater Model Report has been updated to directly address the infiltration pond model run. The recommendations from the groundwater model have not changed. Red Tierra has committed to installing the infiltration pond by including it in the exhibits and it will be included in the bonding calculation. The Division considers the Gilcrest Area Alluvial Groundwater Model report to be the demonstration and justification for the proposed groundwater mitigation plan. Therefore, the mitigation measures described in the report must correspond to the proposed mitigation measures described in permit application exhibits. Please revise the groundwater model report to incorporate the currently proposed mitigation plan to use underdrains and/or extraction wells to transfer mounded groundwater along the southern boundary of the site to an infiltration pond located north of Cell 7. The revised report shall include updates to the Mitigation, Phase 2 Mitigation, Mitigation with Recharge and Conclusion sections of the report, at minimum. Please note, the Applicant is not required to resubmit the appendixes to the report unless the revised report updates the information contained in the appendixes. The report has been revised to show two mitigation scenarios, one where water is removed from the model simulating surface flow to the river and one where flow is directed to the infiltration pond. The surface flow removal scenario was kept in the report in case Red Tierra wishes to apply for an amendment and add it the underdrain discharge line at a later date. The infiltration pond scenario is recommended in the latest revision and Figures 11 and 12 have been added to show the head contours for the two phases described for the infiltration pond mitigation scenario. 2. In response to Item #4, the Applicant stated Exhibit G - Water Information has been updated to " ... or if the miner or the Division receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the ORMS." Exhibit G has been included in the appendices of the Groundwater Model Report and language has been added in the conclusions stating that the operator will comply with the Groundwater Level Monitoring and Mitigation plan. Please commit to investigating all groundwater impact complaints, not just complaints from well owners within 600 feet of the site boundary, received by the Operator or the Division. Please update the groundwater model report and Exhibit G - Water Information accordingly. Please note, the burden to demonstrate any groundwater impacts to the prevailing hydrologic balance is the responsibility of the Permittee. 8308 COLORADO BLVD • SUITE 200 • FIRESTONE, COLORADO 80504 • PHONE: 303.633.1416 • FAX: 303.833.2850 Page 2 Mr. Peter Hays December 1, 2022 Failure by the Permittee to provide adequate demonstration for any groundwater impacts will result in enforcement action by the Division. Noted. Language has been changed to, "or if the miner or the Division receives any groundwater impact complaint, then the miner will evaluate the cause and take action within 7 days and notify the DRMS." Exhibit R - Proof of Filing with County Clerk and Recorder - 6.4.18 3. Please provide an affidavit or receipt indicating the date on which the revised application information required to address this adequacy letter was placed with the Weld County Clerk and Recorder for public review, pursuant to Subparagraph 1.6.2(1)(c). Included. Please feel free to contact me with any questions or concerns at Kyle(a)civilresources.com or my cell number 408-930-2544. Regards, CIVIL RESOURCES, LLC Kyle Regan Project Geologist J:IUnited Water & San -1411Section 201DRMSICorrespondencelDRMSIAdequacylGroundwater Model Response_10102022.doc so COLORADO Division of Reclamation, Mining and Safety Department of Natural Resources December 18, 2022 Kyle Regan Civil Resources, LLC 8308 Colorado Blvd. Suite 200 Firestone, CO 80504 Re: Red Tierra Equities, L.L.C., Section 20 Gravel Mine, File No. M-2022-001, 112c Permit Application Seventh Adequacy Review Mr. Regan: The Division of Reclamation, Mining and Safety (Division/DRMS/Office) reviewed the content of the Red Tierra Equities, L.L.C. 112c permit application sixth adequacy response received on December 9, 2022 for the Section 20 Gravel Mine, File No. M-2022-001 and submits the following comments. The Division is required to issue a recommendation no later than January 26, 2023, therefore a response to the following adequacy review concerns should be submitted to the Division as soon as possible. Groundwater Model 1. In response to Item #3, the Applicant stated the Groundwater Model Report has been updated to directly address the infiltration pond model run. The recommendations from the groundwater model have not changed. Red Tierra has committed to installing the infiltration pond by including it in the exhibits and it will be included in the bonding calculation. The Division considers the Gilcrest Area Alluvial Groundwater Model report to be the demonstration and justification for the proposed groundwater mitigation plan. Therefore, the mitigation measures described in the report must correspond to the proposed mitigation measures described in permit application exhibits. Please revise the groundwater model report to incorporate the currently proposed mitigation plan to use underdrains and/or extraction wells to transfer mounded groundwater along the southern boundary of the site to an infiltration pond located north of Cell 7. The revised report shall include updates to the Mitigation, Phase 2 Mitigation, Mitigation with Recharge and Conclusion sections of the report, at minimum. Please note, the Applicant is not required to resubmit the appendixes to the report unless the revised report updates the information contained in the appendixes. Physical: 1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 Mailing: DRMS Room 215, 1001 E 62nd Ave, Denver, CO 80216 https://drms.colorado.gov Jared S. Polls, Governor 1 Dan Gibbs, Executive Director 1 Virginia Brannon, Director Section 20 7`h Adequacy Letter Page 2 of 2 December 18, 2022 2. In response to Item #4, the Applicant stated Exhibit G - Water Information has been updated to " ... or if the miner or the Division receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the ORMS." Exhibit G has been included in the appendices of the Groundwater Model Report and language has been added in the conclusions stating that the operator will comply with the Groundwater Level Monitoring and Mitigation plan. Please commit to investigating all groundwater impact complaints, not just complaints from well owners within 600 feet of the site boundary, received by the Operator or the Division. Please update the groundwater model report and Exhibit G - Water Information accordingly. Please note, the burden to demonstrate any groundwater impacts to the prevailing hydrologic balance is the responsibility of the Permittee. Failure by the Permittee to provide adequate demonstration for any groundwater impacts will result in enforcement action by the Division. Exhibit R - Proof of Filing with County Clerk and Recorder - 6.4.18 3. Please provide an affidavit or receipt indicating the date on which the revised application information required to address this adequacy letter was placed with the Weld County Clerk and Recorder for public review, pursuant to Subparagraph 1.6.2(1)(c). Please be advised the Section 20 Gravel Mine application may be deemed inadequate, and the application may be denied on January 26, 2023, unless the above mentioned adequacy review items are addressed to the satisfaction of the Division. If more time is needed to complete the reply, the Division can grant an extension to the decision date. This will be done upon receipt of a written waiver of the Applicant's right to a decision by January 26, 2023 and request for additional time. This must be received no later than the decision date. If you have any questions, please contact me at peter.hays@state.co.us or (303) 866-3567 Ext. 8124. Peter S. Hays Environmental Protection Specialist Ec: Jared Ebert, Division of Reclamation, Mining & Safety Patrick Lennberg, Division of Reclamation, Mining & Safety Kyle Regan, Civil Resources, LLC., kyle@civilresources.com GILCREST AREA ALLUVIAL GROUNDWATER MODEL POTENTIAL IMPACTS OF PROPOSED GRAVEL MINING PREPARED FOR: Red Tierra Equities, LLC. 8301 Prentice Avenue Suite 100 Greenwood Village, CO 80111 PREPARED BY: Civil Resources, LLC 8308 Colorado Blvd Suite 200 Firestone, CO 80504 303.833.1416 DATE PREPARED: AUGUST, 2022 REVISED: DECEMBER, 2022 GILCREST AREA ALLUVIAL GROUNDWATER MODEL ACKNOWLEDGMENTS The technical material in this report was prepared by Civil Resources, LLC under the supervision and direction of the undersigned whose seal as a professional engineer is affixed below: ottiurrr,,. Brad Hagen, P.E. rirs�°iisi 1t� The following members of Civil Resources, LLC staff contributed to the study and the preparation of this report: Project Manager: Project Geologist Brad Hagen, P.E. Kyle Regan, P.G. TABLE OF CONTENTS egg 1.0 INTRODUCTION 1 2.0 AREA GEOLOGY 1 3.0 SITE GEOLOGY 1 4.0 EXISTING GROUNDWATER CONDITIONS 2 5.0 GROUNDWATER MODEL 3 5.1 Regional Topography 3 5.2 Bedrock Surface 3 5.3 Hydraulic Conductivity 4 5.4 Specific Yield 4 5.5 Boundary Conditions 4 5.6 Internal Influences 5 6.0 MODEL SIMULATIONS 6 6.1 Existing Conditions 6 6.2 Slurry Wall Installation 7 6.2.1 Monarch Mountain Minerals and Aggregates Site Impacts 8 6.3 Mitigation 9 6.3.1 Mitigation Scenario 1 — Direct Discharge to S. Platte 10 6.3.1.1 Phase 1 10 6.3.1.2 Phase 2 11 6.3.2 Mitigation Scenario 2 — Discharge to Infiltration Pond 12 6.3.2.1 Phase 1 12 6.3.2.2 Phase 2 13 6.3.3 Mitigation With Recharge 12 7.0 CONCLUSIONS 14 8.0 BIBLIOGRAPHY 15 Tables Table 1 Boundary Conditions 5 Table 2 Measured and Modeled Site Groundwater Levels 7 Table 3 Mining Groundwater Level Table (Slurry Walls In -Place) 8 Table 3a Mining Groundwater Level Table with Monarch DENM Site 9 Table 4 Base Model and Modeled Site Groundwater Level After Cell 3 Slurry Wall 10 Table 5 Base Model and Modeled Site Groundwater Level After Cell 3, and 4 Slurry Walls 11 Table 6 Mitigation Scenario 1 Phase 2 — Discharge to S. Platte 12 Table 7 Mitigation Scenario 2 Phase 1 — Discharge to Infiltration Pond 13 Table 8 Mitigation Scenario 2 Phase 2 — Discharge to Infiltration Pond 14 Groundwater Model Report — Section 20 Gravel Mine Site ii August 2022 Fi4ures Figure 1 Figure 2 Figure 3 Figure 4 Figure 4A Figure 5 Figure 5A Figure 6 Figure 6A Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Appendices Regional Bedrock Contours Base Model Conditions Horizontal Hydraulic Conductivity Existing Condition Contours Existing Condition Contours(zoomed to site area) Slurry Wall Full Build Out Condition Contours Slurry Wall Full Build Out Condition Contours(zoomed to site area) Slurry Wall with Drain Condition Contours Slurry Wall with Drain Condition Contours (zoomed to site area) Slurry Wall With Drain and Recharge (zoomed to site area) and Details Cell 3 Slurry Wall Condition Contours Ce// 3, 4 and Monarch DENM Cell 1 Slurry Wall Condition Contours Cell 3, 4, 5N and Monarch DENM Cell 1 Slurry Wall Condition Contours Mitigation Scenario 2 Phase 1 Mitigation with Infiltration Pond Condition Contours Mitigation Scenario 2 Phase 2 Mitigation with Infiltration Pond Condition Contours Appendix A Monthly Water Readings and Diversion Graphs Appendix B Excerpts from Bishop-Brogden Associates, "Dewatering Improvements Study" 2016 Appendix C Excerpts from Principia, "Gilcrest Groundwater Flow Model" 2019 Appendix D Excerpts from Colorado State University, "Study of the South Platte River Alluvial Aquifer" 2013 Appendix E Groundwater Level Monitoring and Mitigation Plan Groundwater Model Report — Section 20 Gravel Mine Site - ii - August 2022 1.0 INTRODUCTION The Section 20 Gravel Mine (Site) is located on Colorado State Highway 60 to the west, Weld County Road 44 to the north, Weld County Road 29 to the east and Weld County Road 42 to the south. More specifically, the Site is comprised of the majority of Section 20, Township 4 North, Range 66 West of the 6th Principal Meridian. The Site is planned to be a construction aggregate material mine to accommodate growth in the area. The current mine plan calls for eight (8) soil bentonite slurry walled cells that will encompass most of the Site excluding approximately 20 acres in the northwest corner of the Site which will wet mined and backfilled with wash fines and waste material. Currently, overburden is being mined in the future Cell 8 under an approved Division of Reclamation Mining and Safety (DRMS) 111 Special Operations Permit. No groundwater is planned to be exposed during this operation. A groundwater model was prepared for Red Tierra Equities, LLC's Section 20 Gravel Mine Site (Site) to investigate the impacts of the final construction of slurry walls at the Site on the surrounding alluvial aquifer. This report details the model inputs and construction, the findings of the model and recommendations to mitigate alluvial aquifer impacts. 2.0 AREA GEOLOGY The Site is located approximately 25 miles east of the eastern flank of the Rocky Mountain Front Range. Younger sedimentary strata dip eastward off the Pre -Cambrian igneous and metamorphic rocks that form the core of the Front Range into the Denver Structural Basin. The Denver Basin is an asymmetrical downwarp of sedimentary strata with a steeply dipping west limb and a gently dipping east limb. Bedrock does not crop out at the Site, however regional geologic mapping of the area (Colton, 1978) indicates the near surface bedrock at the Site is most likely the Laramie Formation. Colton (1978) describes the Laramie Formation as mostly claystone, shale, sandy shale, and lenticular sandstone (refer Figure 1). The regional mapping indicates the bedrock is overlain by the Broadway Alluvium. Colton (1978) describes these alluvial deposits as sand and gravel deposited by the South Platte River and its tributaries. In addition to the sonic borings drilled by Cascade, Civil Resources analyzed and mapped bedrock from 177 well logs from the Division of Water Resources. As shown on Figure 2, bedrock in the area generally slopes to the northeast following the route of the South Platte River. Approximately one and a half (1.5) miles southeast of the South Platte River the bedrock drops in elevation dramatically from an elevation of 4696 feet in the northwest corner of Section 20 to an elevation of 4664 feet around the Town of Gilcrest. On the southeastem side of Highway 85 the bedrock rises to an elevation of 4719 feet on the southeast side of Highway 85. 3.0 SITE GEOLOGY A total of 23 borings were drilled to bedrock at the Section 20 Site. Depth to bedrock ranged from 39.5 feet in BH-38 in the northeast corner of the Site to 97.5 feet in BH-41 in the southeast corner of the Site. The bedrock encountered at the Site consisted of wet brown weathered claystone in the first 6 inches to 1 foot which transitioned in to moist to dry, olive to grey claystone with further depth. The claystone had a high plasticity and minimal fracturing. The bedrock unit was not sampled. Depth to bedrock is mapped out in Figure 1. The alluvial aquifer at the Site consist mainly of gravelly sand which grades to sandy gravel, usually becoming more gravelly with depth. Some cobble units (grain size 4" or greater) were encountered at the Site; mainly consisting of a few feet overlaying bedrock. Aggregate unit thickness varied from 35 feet in BH-36 in the northern side of the Site to 72.5 feet in BH-27 in the eastern side of the Site. Groundwater Model Report — Section 20 Gravel Mine Site -1 - August 2022 4.0 EXISTING GROUNDWATER CONDITIONS Groundwater was measured in seven (7) piezometers, and typically occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the Site. The prevailing groundwater flow direction at the Site is to the north reflecting the Site topography. Groundwater in the area is tributary to the South Platte River located northwest of the Site. Depth to groundwater is shallower, as little as 5 feet, underlying the Town of Gilcrest likely due to the deep bedrock and low topography relative to the surrounding area. Locally the groundwater levels and flow directions are influenced by: ➢ The South Platte River is northwest of the Site. For most of the year, the river likely acts as a drainage way, or gaining river reach, maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the Site under the intersection of Weld County Road 42 and Weld County Road 29. North of Weld County Road 36, the ditch joins with a wetland drain which likely provides water year-round. During the irrigation season, the ditch diverts water from the South Platte River as well raising the water level of the ditch. ➢ The Farmers Independent Ditch traverses the southeast comer of the Site and bisects Cell 5a and 5b. The ditch flows most of the year based on diversion records for the ditch headgate located southwest of Platteville. ➢ The Evans #2 Ditch passes southeast of the Town of Gilcrest on the eastem side of Highway 85. The ditch did not have discharge during the months of November and December but did have flow during the remainder of the year. > The Platte Valley Ditch branches off from the Evans #2 Ditch south of the Town of Gilcrest. The Platte Valley Ditch does not have a stream gage, so it was assumed that it was flowing at the same time as the Evans #2 Ditch. > There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the Site during the irrigation season. ➢ There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the Site during the irrigation season. ➢ There are two unnamed sloughs approximately /≥ a mile to the west and another a'A mile to the north of the Site respectively. These sloughs receive groundwater flowing out from the higher terrace and act as drains moving water to the river. > There are multiple recharge ponds it the area of interest which provide groundwater recharge (refer Figure 2). ➢ Irrigation: The Site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration recharges the groundwater. Groundwater Model Report — Section 20 Gravel Mine Site - 2 - August 2022 ➢ Alluvial wells: Other than the seven monitoring wells drilled at the Site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the Site, two wells east of the Site, nine wells south of the Site and one well west of the Site. If pumping, groundwater will be drawn to these wells. 5.0 GROUNDWATER MODEL The MODFLOW program utilizes a finite -difference mathematical model to simulate groundwater flow developed by the United States Geological Survey (USGS). Groundwater Modeling System (GMS V 10.4.10) provided the graphical user interface for entering and reviewing the MODLFOW data. The model has a total area of approximately 42 square miles, extending from the South Platte River to the west, the Town of Platteville to the south, the Evans #2 Ditch to the east and the Town of La Salle to the north (refer to Figure 1). The grid size is 200 feet by 200 feet squares. The following boundary conditions were applied to the model as presented in Figure 2: > South Platte River to the northwest (River Package within MODFLOW); ➢ A constant head boundary to the south; ➢ A no flow boundary to the east to simulate the rise in bedrock east of Highway 85; ➢ A constant head boundary to the north; > Claystone bedrock — acting as an aquitard forming the bottom of the aquifer. The shallow alluvial aquifer was modeled as a single aquifer (sand and small gravel), with zoned hydraulic conductivities based on historical well pumping tests, underlain by impervious claystone bedrock. The model parameters and boundary conditions, such as Site topography, bedrock elevations, and hydraulic conductivities are further discussed in the following sections. 5.1 Regional Topography Surface topography was obtained from USGS digital quadrangle (the Milliken 7.5 minute quadrangle). The digital map was converted into a Civil 3d surface and imported to GMS and interpolated to the top elevations of the aquifer layer. 5.2 Bedrock Surface The bedrock surface for the Site was obtained from borings completed by Civil Resources at the Site as well as 177 wells logs retrieved from the Colorado Division of Water Resources webSite. These points were entered into Civil 3d to create a surface and smoothed using natural neighbor interpolation with a 20 -foot by 20 -foot interval. Bedrock is exposed to the west of the South Platte River, indicating that the alluvial aquifer pinches out to the west. A feature line was used to map out the bedrock outcrop to bring the bedrock surface to meet the ground surface west of the river. Corrections were made to this surface to lower the bedrock in areas in order to maintain usable cells along the river corridor and bedrock is likely shallower than the model input in this region. 5.3 Hydraulic Conductivity Hydraulic conductivity is a measure of the soils ability to transmit water within the aquifer. Some factors affecting hydraulic conductivity are: pore size distribution, grain size distribution, void ratio, roughness of mineral particles, and Groundwater Model Report— Section 20 Gravel Mine Site - 3 - August 2022 degree of soil saturation (Das, 1998). The alluvium, underlying the region, is generally a clean to silty sand and gravel, as described above with an approximate depth of 50 to 95 feet in the upper terrace and shallower than 10 feet along the South Platte River floodplain. Aquifer properties used in a previous study of the area performed by Bishop-Brogden Associates, Inc.(BBA) for the Town of Gilcrest were incorporated as this report utilized two long-term aquifer pumping tests in the vicinity of Gilcrest: the B4-66-11adc well 3 miles north of Gilcrest and the Lorenz Well approximately'/z mile to the east of Gilcrest. ➢ The B4-66-011 adc well approximately 3 miles north of Gilcrest is the nearest controlled long-term aquifer pumping and showed a hydraulic conductivity of 1,270 ft/day. ➢ BBA performed an analysis of water level data from observation wells located near the Lorenz Well approximately / mile to the east of Gilcrest. Their analysis indicated a hydraulic conductivity of approximately 150 ft/day. The hydraulic conductivity was set at the lower end of the ranges provided by BBA and were increased until the model heads converged. The model is sensitive to horizontal hydraulic conductivity and operates without errors in a narrow range of values at the high end of the ranges provided by BBA. Horizontal hydraulic conductivity for the calibrated model range from a low of 65 ft/day for the hills to the east and a high of 805 ft/day underlying the Site. An area of high horizontal hydraulic conductivity. A map with the horizontal hydraulic conductivity values utilized in the model is shown on Figure 3. 5.4 Specific Yield Specific yield for the aquifer was set at 20% which corresponds to the value determined by BBA and in support of numerous water court decrees. 5.5 Boundary Conditions Boundary conditions were set based on geologic features on the east and west sides of the model. The constant head boundaries on the south and north sides were varied to match observed groundwater data sets. ➢ Boundary conditions in a groundwater model are one tool used to approximate existing conditions at the outer extent of the model. The boundary conditions are set sufficiently far away from the area of interest to allow the aquifer to respond to local stresses and are based on hydraulic, hydrogeologic, hydrologic, geological and geographical assumptions. ➢ The model extends 3.3 miles southwest where constant head nodes were placed approximately 14 feet below the ground surface to represent existing groundwater levels taken in the area. ➢ Another constant head boundary was place approximately 3.7 miles northeast Site and constant head nodes were placed on the southeastern flank at water surface elevations approximately ten feet below the ground. ➢ To the southeast of the model surface topography and bedrock slope up in elevation creating a natural barrier to flow. The eastern limit of the alluvial aquifer was confirmed by researching the states database of permitted wells in the area and mapping where the permitted aquifer switches from the alluvial aquifer to a deep confined aquifer. The approximate location of the shallow and deep aquifer divide is approximately 'A mile east the location of the Platte Valley Ditch. ➢ The South Platte River forms a natural hydrologic boundary to the west of the model. Model inputs for the MODFLOW river package are bottom elevation, head -stage and conductivity. The bed elevation was estimated using the USGS topographic quadrangle and Google Earth top of bed elevation and subtracting 6 feet to Groundwater Model Report — Section 20 Gravel Mine Site - 4 - August 2022 account for riverbed depth. Head -stage was taken from the South Platte River at Platteville, CO (PLAPLACO) monitoring station which was approximately 4' during the period of interest. See Appendix A for the PLAPLACO station discharge graph. ➢ River conductance is a model parameter in the river package which simulates the riverbed's ability to transfer water to the neighboring cell. The river conductance parameter is calculated by taking vertical hydraulic conductivity divided by bed thickness multiplied by river width. This value is then multiplied by GMS for the length of the river arc to which it is applied. Since the riverbed hydraulic conductivity is unknown for this reach of the South Platte River, it was necessary to calibrate this parameter to groundwater conditions at the Site. An initial conductance of 36 ft/day was determined from well test reports that occurred upstream of the Site north of Fort Lupton. Since the South Platte River acts as a drain throughout the reach, conductance values less than 150 ft/day caused unrealistic head values and flooded cells. Values higher than 160 ft/day cause head values to drop and dry cells through the area. The river conductance was modeled to increase from 150 ft/day where the river enters the model to 160 ft/day where the river exits the model. The rise in conductance was implemented to account for an increase in river width after the addition of the Saint Vrain River and groundwater inflows. A summary of the boundary conditions is presented in Table 6 below. Table 1 Boundary Conditions Area Boundary Notes North Model extends 3.7 miles to the northeast See Figure 1 West South Platte River located approximately 4,000 feet west of Site River bounds the westem side of the model, see Figure 1 South Model extends 3.3 miles to the southwest Constant head nodes, see Figure 1 East Steeper Slopes to a ridge, wells change from shallow to deep See Figure 1 The model boundary conditions are shown on Figure 2 5.6 Internal Influences Surface features and activities that affect the alluvial groundwater include: ➢ Ditches — There are four (4) ditches that traverse the interior of the model. These ditches were modeled in GMS as river nodes. As discussed in the South Platte River boundary condition above, the model inputs for the MODFLOW river package are: bottom elevation, head -stage, and conductance. The bed thickness for the ditches were all assumed to be 2 feet thick and to have a relatively low vertical hydraulic conductivity to limit seepage and were used as a calibration tool to match local groundwater elevations. Head stage was estimated from the FRMDITCO, WESDITCO, EVANS2CO river diversion monitoring stations(See Appendix A). The HB12-1278 Study of the South Platte River Alluvial Aquifer, performed by Colorado State University, states that calculated ditch seepage in the ranges from 10 to 50 percent, averaging at 23 percent. In the area of interest, ditch width ranges from approximately 10 feet wide to 30 feet wide. Assuming the 2 -foot bed thickness and starting with 10 percent seepage, ditch conductance was set at 0.5 ft/day and was raised incrementally until known groundwater head elevations and gradient were Groundwater Model Report — Section 20 Gravel Mine Site - 5 - August 2022 reached. It was assumed that seepage from the ditches reduced over distance as water was consumed. See Figure 1 for inputted parameters. The Western Mutual Ditch was the main factor in determining head values at the Section 20 Site and small changes in head elevation and conductance were used to calibrate the river input to reach observed head measurements throughout the Site. ➢ Drains — A series of drains were set at the base of three sloughs along the South Platte River. These drains were necessary to pull head elevations down to the slough elevation and not flood out the cells in the floodway. The drain inputs are bottom elevation and conductance. The bottom elevation was estimated from the USGS Quadrangle Map and were assumed to be at least 2 feet deep. The conductance input was set high enough to account for all water that was above the drain bottom to model the slough action of removing groundwater and setting groundwater head levels at the base of the terrace. ➢ Recharge — A number of upgradient recharge Sites were listed in the BBA report and were added to this model. The recharge values and location are located on Figure 2. It was assumed that pivot and flood irrigation contributed 0.001 feet per day to the groundwater table over the whole model area during irrigation season. 6.0 MODEL SIMULATIONS 6.1 Existing Conditions Steady-state modeling of average baseline conditions of April through July were used to calibrate the system equilibrium to the measured water levels. Monthly water level readings and other reported data can be seen in Appendix A. The aquifer was modeled as consisting of alluvium from the existing ground surface to the top of bedrock. Civil Resources evaluated the claystone bedrock as an aquiclude, thereby forming the bottom of the model. The observed water levels used to calibrate the steady-state model are shown on Figure 1. Calibration is the process of refining input parameters and boundary conditions, within reason, so the model reflects observed water levels. Parameters including: 1) hydraulic conductivity, 2) river conductance, 3) river head, 4) river bottom elevations, and 5) drain conductance were adjusted during calibration. The groundwater levels to the northeast were estimated from the level of the Lower Latham Reservoir. Groundwater levels to the southwest were estimated from monitoring wells in the area. The South Platte River, ditches and drain bottom elevations were estimated utilizing the USGS Quadrangle map and water surface elevations were estimated using stream gage head information from the DWR website(See Appendix A). Figure 5 shows the modeled groundwater contours and Figure 5A shows the modeled groundwater contours zoomed in on the Site and the Town. Table 2 below reports the steady-state modeled water levels and the measured water levels at the Site. Overall, the model matched the existing groundwater gradient to a good degree of accuracy and 6 out of the 7 Site monitoring wells were within 0.5 feet of observed. MW -1 was 2' above the observed head elevation. ➢ MW -1 was drilled approximately 50 feet from a residence at the property and a search of well permits on the DWR Site shows that there are multiple wells, 3 owned by Red Tierra Equities LLC., are located within a 400 foot radius of the monitoring well. There is also a domestic well approximately 500 from MW -1 across Highway 60. These wells may locally influence the groundwater resulting in lower water levels observed in MW -1 than modeled, especially given that the gradient matches across the rest of the Site. Groundwater Model Report— Section 20 Gravel Mine Site - 6 - August 2022 Groundwater levels for monitoring wells in the Town of Gilcrest were also utilized in calibration of the model. The BBA report contained well readings from multiple wells in the Town of Gilcrest measured in 2014. It was assumed that these readings were similar to current head elevations and four (4) monitoring wells were included to get a representative sample of the Town. Of the four(4) wells chosen, three (3) of them were within 0.5 feet of observed. BBA-EC, northeast of town on the eastern side of Highway 85 was 1.5 feet lower than the observed elevation head. The monitoring wells included in the BBA report were recorded in 1 foot intervals, which could account for the 1.5 feet difference. Table 2 below has the comparison between the measured and modeled groundwater levels at the Site. The head contours for the baseline condition are shown on Figure 4. Table 2 Measured and Modeled Site Groundwater Levels Well Observed Modeled Difference Cell (IJK) MW -1 4,725.40 4727.1 1.70 146,111,1 MW -2 4,718.17 4717.9 -0.27 136,119,1 MW -3 4,725.07 4724.9 -0.17 142,136,1 MW -4 4,732.07 4732.5 0.43 153,136,1 MW -5 4,736.43 4736.7 0.27 162,133,1 MW -6 4,738.43 4737.7 -0.73 162,115,1 MW -7 4,728.92 4728.9 -0.02 148,122,1 BBA-MW4 4741 4740.3 -0.70 148,122,1 BBA-MW11 4737 4736.9 -0.10 148,122,1 BBA-MW17 4735 4734.4 -0.60 166,164,1 BBA-MW18 4738 4737.25 -0.75 148,122,1 DROU-MW-01 4741.5 4743.4 1.90 177,86,1 DROU-MW-02 4743 4744 1.00 176,94,1 DROU-MW-03 4747.1 4747.3 0.20 182,93,1 DROU-MW-04 4749.1 4750 0.90 187,93,1 DROU-MW-05 4746.6 4746.8 0.20 183,84,1 6.2 Slurry Wall Installation Simulation The Site is planned for a sequence of soil bentonite slurry wall lined cells encompassing the majority of the Site. The only area not planned to be slurry wall lined is the siltation pond in the northwest corner of the Site and a potential recharge pond north of Cell 7. The slurry walls will be constructed in stages starting in the northeast and progressing south then west (see attached Mine Plan for phasing). In order to model for the worst -case scenario, the model includes a simulated slurry wall around the whole section, minus the Siltation Pond area. To make the Site a no flow area, the horizontal hydraulic conductivity of the Site was set to zero (0) feet/day. The area where the Westem Mutual Ditch runs through the Site remained at the 805 feet/day horizontal hydraulic conductivity. The mounding and shadowing for the surrounding properties and wells is described in Table 3 below: Groundwater Model Report — Section 20 Gravel Mine Site - 7 - August 2022 Table 3 Mining Groundwater Level Table (Slurry Walls In -Place Location Basement (y/n) Baseline After Slurry Wall Construction Difference (FT Rise or Fall) Groundwater Depth Below Surface Surface Elevation (Google Earth) Cell (IJK) Patridge House n 4736.3 4743.2 6.9 20.8 4764 161,135,1 Cline House n 4736.8 4745.1 8.3 20.9 4766 162,132,1 Hating House y 4736.6 4746.0 9.3 19.1 4765 161,129,1 Wiedeman House 13434 n 4738.2 4747.3 9.1 20.7 4768 163,121,1 Wiedman House 13218 n 4738.5 4747.0 8.5 15.0 4762 163,115,1 Sharp House y 4738.4 4745.7 7.3 14.4 4760 163,111,1 HS Land and Cattle n 4732.6 4736.1 3.5 18.9 4755 155,107,1 Karbowski Brave House n 4725.5 4724.5 -1.0 27.5 4752 145,108,1 Schmidt Well NA 4714.4 4709.6 -4.8 23.4 4733 132,112,1 United Well NA 4712.0 4706.7 -5.3 41.3 4748 132,126,1 Owens Well NA 4714.2 4711.2 -3.0 34.8 4746 132,133,1 Wright House y 4717.4 4712.2 -5.2 39.8 4752 135,132,1 Schmidt -House n 4718.4 4717.0 -1.4 31.D 4748 135,135,1 Smit House y 4718.8 4718.4 -0.4 29.6 4748 135,136,1 Kissler House y 4729.5 4733.3 3.8 21.7 4755 148,137,1 Woolverton House y 4730.8 4734.9 4.1 27.1 4762 150,136,1 Shimon House y 4733.0 4737.9 4.9 21.1 4759 154,136,1 Kem House y 4733.8 4739.0 5.1 21.1 4760 156,137,1 RainboltHouse y 4735.9 4742.2 6.3 22.8 4765 161,137,1 Gilcrest Valley HS NA 4737.0 4740.7 3.7 5.3 4746 170,155,1 As noted in the table above, groundwater elevation impacts from the installation of the slurry walls wil be highly spatially variable. The southeast corner of the Site is expected to see the most amount of mounding, up to 9.4 feet above baseline levels. However, the groundwater table in this area is very deep (from 27 to 30 feet deep), so flooding is not expected to be an issue. Mounding decreases on the upgradient side from east to west, with the Sharp house on the southwest corner of the Site potentially seeing 7.3 feet of mounding. Elevation from Google Earth for the Sharp property is approximately 4760 feet which would put the potential groundwater rise at fourteen (14.4) feet below the surface. Potential shadow effects from the slurry wall are present north of the Site (downgradient). There are three (3) wells on the north side of the Site which will be in the groundwater shadow and changes in depth to groundwater vary from three (2) feet lower to five (5) feet lower for the United well. The shadow effect is likely mitigated by the proximity of the slough to the north of the Site and the infiltration ponds to the northeast of the Site. The modest shadow effect should have limited effect on the productivity local alluvial wells. The Town of Gilcrest is located between the Site and a rise in the bedrock elevation to the east which acts as a no flow boundary. It is anticipated that slurry wall construction will restrict flow to the west of Town causing Elevated groundwater levels in Town as noted for "Gilcrest Valley HS" in the table above. 6.2.1 Monarch Mountain Minerals and Aggregates Site Impacts In addition to the Section 20 Gravel Mine, the Monarch Mountain Minerals and Aggregates (MMMA) Monarch DENM Gravel Mine is permitted by the DRMS on the west side of Highway 60. This site is comprised of four (4) slurry wall lined cells and three (3) unlined cells along Highway 60. To simulate the four (4) lined cells, the horizontal hydraulic conductivity in these areas was set to zero (0). To simulate the end stage of the mine it was anticipated that the Groundwater Model Report— Section 20 Gravel Mine Site - 8 - August 2022 Freshwater and Siltation ponds would be filled in with overburden at the site which would lower their horizontal hydraulic conductivity to be similar to the Eolian deposits in the area. The horizontal hydraulic conductivity in these areas was set to 65 feet per day. The additional impacts from adding this site to the model are presented in Table 3a below and a layout of the site is shown on Figure 5 and 5A. Table 3a Mining Groundwater Level Table With Monarch DENM Site ISlurry Walls In -Place Location Basement (y/n) Baseline After Slurry Wall Construction Difference (FT Rise or Fall) Groundwater Depth Below Surface Surface Elevation (Google Earth) Cell (IJK) Patridge House n 4736.3 4745.5 9.2 18.5 4764 161,135,1 Cline House n 4736.8 4747.7 10.9 18.3 4766 162,132,1 Harding House y 4736.6 4748.8 12.2 16.2 4765 161,129,1 Wiedeman House 13434 n 4738.2 4750.8 12.6 17.2 4768 163,121,1 Wiedman House 13218 n 4738.5 4751.2 12.7 10.8 4762 163,115,1 Sharp House y 4738.4 4750.9 12.5 9.1 4760 163,111,1 HS Land and Cattle n 4732.6 4744.7 12.1 10.3 4755 155,107,1 Karbowski Brave House n 4725.5 4731.5 6.0 20.5 4752 145,108,1 Schmidt Well NA 4714.4 4710.4 -4.0 22.6 4733 132,112,1 United Well NA 4712.0 4707.0 -5.0 41.0 4748 132,126,1 Owens Well NA 4714.2 4711.7 -2.5 34.3 4746 132,133,1 Wright House y 4717.4 4712.8 -4.6 39.2 4752 135,132,1 Schmidt House n 4718.4 4717.7 -0.7 30.3 4748 135,135,1 Smit House y 4718.8 4719.2 0.4 28.8 4748 135,136,1 KissierHouse y 4729.5 4734.8 5.3 20.2 4755 148,137,1 Woolverton House y 4730.8 4736.5 5.7 25.5 4762 150,136,1 Shimon House y 4733.0 4739.7 6.7 19.3 4759 154,136,1 Kern House y 4733.8 4740.9 7.1 19.1 4760 156,137,1 Rainbolt House y 4735.9 4744.4 8.5 20.6 4765 161,137,1 Gilcrest Valley HS NA 4737.0 4742.5 5.5 3.5 4746 170,155,1 The addition of the full build out of the Monarch DENM Site increases mounding on the southern side of the Section 20 Site by limiting groundwater flow to the west. Slurry Walls along Highway 60 and the addition of the Monarch DENM Siltation and Freshwater ponds creates a groundwater corridor along Highway 60 north to the South Platte River, which causes the groundwater at the HS Land and Cattle building to rise approximately twelve (12) feet from baseline conditions. 6.3 Mitigation This section describes potential mitigation actions to decrease the mounding affect of slurry wall construction on the surrounding properties and the Town. The Monarch DENM Gravel Mine timeline submitted to the DRMS was utilized in conjunction with the Section 20 expected timeline to determine the phasing of mitigation construction. These timelines are approximate and are subject to change which may necessitate early construction of mitigation structures depending on measured groundwater conditions at the Site. The groundwater table to the south of the Site and underlying the Town of Gilcrest is anticipated to rise as a result of the full buildout of the slurry walls at the Site and the Monarch DENM Site. Mitigation for mounding is warranted at the southern end of the Site. The mounding is expected to be greatest towards the southwest corner of the Site and decreases to the east at full buildout. Mounding of more than two (2) feet at the south site perimeter, monitoring wells Groundwater Model Report — Section 20 Gravel Mine Site - 9 - August 2022 MW -5 and MW -6, coincides with an approximate one (1) foot rise in town. To mitigate against possible groundwater elevation rise in town, a two (2) foot cut off was used to implement mitigation at the southern site boundary. The shadow affect to the north will likely be minimized by the proximity to the unnamed slough and the infiltration ponds to the northeast of the Site. During mining at the Site, an unlined siltation pond will be present in the northwest corner of the Site which will also mitigate some of the shadow affect. Mitigation for the shadow affect is not anticipated to be necessary since the saturated thickness of the alluvial deposit is eighteen (18) to twenty (20) feet a full buildout of both sites. Even though mitigation is not anticipated to be necessary for the shadow affect to the north, it is recommended that an infiltration pond be installed north of Cell 7 to receive the rerouted groundwater from the south of the site. This will enable all the mitigation infrastructure to be constructed within the Division of Reclamation, Mining, and Safety's Affected Area Boundary. Two (2) mitigation scenarios were modeled to provide optionality for the method of return of the groundwater to the hydrologic system; either directly to the river or through infiltration. Each scenario was modelled in two (2) phases coinciding with the construction schedule of the Site and the Monarch DENM slurry walls. The first phase is an underdrain or series of dewatering wells along the eastern half of the site parallel to Weld County Road 42. The second phase is the construction of an underdrain between Cell 6 and the Western Mutual Ditch west of where the ditch crosses onto the property to approximately 200 feet east of Highway 60. 6.3.1 Mitigation Scenario 1— Direct Discharge to the South Platte This mitigation scenario utilized the Well and Drain Package to remove water from the model. Water is not returned to the model to simulate surface discharge or direct discharge to the South Platte. This option would require an Amendment to the DRMS Reclamation Permit Application or Permit to add the underdrain discharge pipe to the Affected Area. The exact route for the offsite underdrain discharge pipe for this Scenario is not discussed in this report. 6.3.1.1 Phase 1 Mounding at the southern end of the Site boundary and in Town is not expected to rise more than two (2) feet before the construction of the Cell 4 slurry wall so mitigation is not warranted until the Cell 4 slurry wall is constructed or Site monitoring observes a higher than anticipated groundwater elevation at the southern monitoring wells(MW-5 and MW -6). See Table 4 below and Figures 8 and 9. Table 4 Base Model and Modeled Site Groundwater Level After Cell 3 Slurry Wall Well Base Modeled Cell 3, 4 and 5N Slurry Wall Difference Cell (IJK) MW -1 4,726.9 4,726.4 -0.5 146,111,1 MW -2 4,717.8 4,716.0 -1.8 136,119,1 MW -3 4,725.0 4,725.8 0.8 142,136,1 MW -4 4,732.5 4,734.1 1.6 153,136,1 MW -5 4,736.7 4,736.8 0.1 162,133,1 MW -6 4,738.4 4,737.2 -1.2 162,115,1 MW -7 4,729.1 4,728.2 -0.9 148,122,1 BBA-MW4 4,741.3 4,740.9 -0.4 148,122,2 BBA-MW11 4,737.1 4,737.5 0.4 148,122,3 BBA-MW18 4,738.6 4,738.9 0.3 148,122,4 BBA-EC 4,732.5 4,732.9 0.4 148,122,5 A series of wells were modelled at the southeastern corner of the site after the addition of the Cell 4 slurry wall and the Monarch DENM Cell 1 slurry wall. These wells were set to pump 2.25 cubic feet per second(CFS) and removed the Groundwater Model Report — Section 20 Gravel Mine Site -10- August 2022 groundwater from the model simulating return flow back to the river. Table 5 below shows the groundwater head elevations at the monitoring well locations for this model iteration. Table 5 Base Model and Modeled Site Groundwater Level After Cell 3, 4 SW with Dewatering Wells Well Base Modeled Cell 3 and 4 Difference Cell (IJK) MW -1 4,727.1 4,727.5 0.4 146,111,1 MW -2 4,717.9 4,716.8 -1.1 136,119,1 MW -3 4,724.9 4,726.0 1.1 142,136,1 MW -4 4,732.5 4,733.6 1.1 153,136,1 MW -5 4,736.7 4,736.0 -0.7 162,133,1 MW -6 4,737.7 4,738.2 0.5 162,115,1 MW -7 4,728.9 4,730.7 1.8 148,122,1 BBA-MW4 4,740.3 4,740.5 0.2 148,122,1 BBA-MW11 4,736.9 4,737.0 0.1 148,122,1 BBA-MW17 4,734.4 4,734.5 0.1 166,164,1 BBA-MW18 4,737.3 4,737.4 0.1 148,122,1 The quantity of water required to be pumped or gravity drained away from the southeastern corner increases as more slurry walls are constructed. After Cell 5N is constructed, the modeled pumping rate was increased to 2.5 CFS spread over three (3) wells to maintain pre -slurry wall groundwater elevations south of the Site (see Figure 10). The modeled pumping rate was further increased to 3.25 CFS with the addition of Cell 5S. 6.3.1.2 Phase 2 The mitigation in Phase 2 was modeled to be completed concurrently with Cell 6. This included an addition of an underdrain in the southwest corner of the site between the Western Mutual Ditch and the Cell 6 slurry wall. The pipe invert elevation for the underdrain was set at 4,735 feet in the east and 4,733 feet in the west. This section of pipe was modeled to remove water from the model to simulate piped gravity flow to the river. The modeled quantity of water that was removed by the drain was approximately 3.3 CFS (287,344 cubic feet per day) at full buildout of both sites. An underdrain was included at the Monarch DENM site between the Cell 3 Slurry Wall and Weld County Road 42 to account for MMMA's contribution to mounding in the area. The pipe invert elevations were set at 4,733 feet in the east and 4,732.9 feet in the west and removed approximately three (3) CFS from the model. Table 6 depicts the groundwater levels for the surrounding properties at the full buildout of the site and the site layout and phasing is shown on Figure 6 and 6A. Groundwater Model Report — Section 20 Gravel Mine Site -11- August 2022 Table 6 Mitigation Scenario 1 Phase 2 — Discharge to S. Platte Location Baseline Full Buildout and Mitigation (All SW) Difference From Baseline Conditions Patridge House 4736.3 4736.0 -0.33 Cline House 4736.8 4737.3 0.50 Harding House 4736.6 4737.8 1.25 Wiedernan House 13434 4738.2 4739.6 1.40 Wiedman House 13218 4738.5 4738.1 -0.40 Sharp House 4738.4 4738.0 -0.44 HS Land and Cattle 4732.6 4732.1 -0.50 Kabowski Brave House 4725.5 4722.9 -2.55 Schmidt Well 4714.4 4708.9 -5.54 United Well 4712.0 4706.3 -5.69 Owens Well 4714.2 4710.2 -4.00 Wright House 4717.4 4711.1 -6.30 Schmidt House 4718.4 4715.3 -3.10 Smit House 4718.8 4716.5 -2.30 Kissler House 4729.5 4729.4 -0.10 Woolverton House 4730.8 4730.7 -0.10 Shinion House 4733.0 4733.1 0.10 Kern House 4733.8 4733.9 0.10 Rainbolt House 4735.9 4736.0 0.08 Gilcrest Valley HS 4737.0 4736.6 -0.37 6.3.2 Mitigation Scenario 2- Discharge to Infiltration Pond Scenario 2 is similar to Scenario 1 in that it uses the Drain and Well Packages to remove water from the model. Scenario 2 then utilizes the Recharge Package to add the approximate amount of water removed back to the model in the cells north of Cell 7 to simulate an infiltration pond in that location. Discharging to an infiltration pond located onsite is the recommended scenario because it will allow all infrastructure to be constructed inside of the DRMS Affected Area boundary and has the added benefit of mitigating the drop of groundwater head elevations to the north of the site as a result of slurry wall obstruction. 6.3.2.1 Phase 1 In addition to the underdrain or dewatering wells discussed in Section 6.3.1.1, the infiltration pond will be constructed prior to the Cell 4 slurry wall and the underdrain or dewatering wells. Water is removed from the system by the dewatering wells or underdrain and piped to a manhole located towards the southern end of the site west of the Western Mutual Ditch. Water is then piped north through the middle of the site to the infiltration pond. The infiltration pond is expected to be five (5) acres in size, approximately twenty-five (25) feet in depth north of Cell 7, and completed in native aggregate. The recharge rate for the pond area was set to 0.705 feet per day which resulted in 281,044 cubic feet per day of recharge or 3.25 cubic feet per second, which corresponds to the amount of water removed by the Well Package. Figure 11 depicts the site layout for this phase and the head contours. Table 7 shows the groundwater head elevation for the wells to the north of the site: Groundwater Model Report— Section 20 Gravel Mine Site -12 - August 2022 Table 7 Mitigation Scenario 2 Phase 1— Discharge to Infiltration Pond Location Basement (y/n) Baseline Phase 1 with Recharge Difference (FT Rise or Fall) Groundwater Depth Below Surface Surface Elevation (Google Earth) Cell (IJK) Patridge House n 4736.3 4736.0 -0.3 28.0 4764 161,135,1 Cline House n 4736.8 4737.3 0.5 28.7 4766 162,132,1 Harding House y 4736.6 4737.8 1.2 27.2 4765 161,129,1 Wiedeman House 13434 n 4738.2 4739.3 1.1 28.7 4768 163,121,1 Wiedman House13218 n 4738.5 4737.8 -0.7 24.2 4762 163,115,1 Sharpe House y 4738.4 4738.0 -0.4 22.0 4760 163,111,1 HS Land and Cattle n 4732.6 4732.9 0.3 22.1 4755 155,107,1 Karbowski Brave House n 4725.5 4724.9 -0.6 27.1 4752 145,108,1 Schmidt Well NA 4714.4 4713.4 -1.0 19.6 4733 132,112,1 United Well NA 4712.0 4714.0 2.0 34.0 4748 132,126,1 Owens Well NA 4714.2 4712.3 -1.9 33.7 4746 132,133,1 Wright House y 4717.4 4714.2 -3.2 37.8 4752 135,132,1 Schmidt House n 4718.4 4716.6 -1.8 31.4 4748 135,135,1 Smit House y 4718.8 4717.5 -1.3 30.5 4748 135,136,1 Kissler House y 4729.5 4729.6 0.1 25.4 4755 148,137,1 Woolverton House y 4730.8 4730.9 0.1 31.1 4762 150,136,1 Shimon House y 4733.0 4733.3 0.3 25.8 4759 154,136,1 Kem House y 4733.8 4734.0 0.2 26.0 4760 156,137,1 Rainbolt House y 4735.9 4736.0 0.1 29.0 4765 161,137,1 Gilcrest Valley HS NA 4737.0 4736.7 -0.3 9.3 4746 170,155,1 6.3.2.2 Phase 2 The mitigation in Phase 2 was modeled to be completed concurrently with Cell 6. Like Scenario 1, a twenty-four 24 inch slotted underdrain was placed south of Cell 6. The underdrain, instead of flowing west, will flow east towards the manhole west of the Western Mutual Ditch were it will join the flow from the eastem underdrain or dewatering wells. To enable water to flow east the inverts of the underdrain were changed to 4,733.5' in the west and 4,733.0' in the east, where it flows into the manhole and is combined with the flow from the east. This adds approximately 3.3 cubic feet per second, 287,344 cubic feet per day. The recharge rate for the infiltration pond was set to 1.43 feet per day which added 570,062 cubic feet per day or 6.6 cubic feet per second into the water table and had the following effects on the wells north of the site: Groundwater Model Report — Section 20 Gravel Mine Site -13 - August 2022 Table 8 Mititaation Scenario 2 Phase 2 — Dischartae to Infiltration Pond Location Basement (y/n) Baseline Phase 2 with Recharge to Infiltration Pond Difference (FT Rise or Fall) Groundwater Depth Below Surface Surface Elevation (Google Earth) Cell (IJK) Patridge House n 4736.3 4736.0 -0.3 28.0 4764 161,135,1 Cline House n 4736.8 4737.3 0.5 28.7 4766 162,132,1 Harding House y 4736.6 4737.8 1.2 27.2 4765 161,129,1 Wiedeman House 13434 n 4738.2 4739.3 1.1 28.7 4768 163,121,1 W9edman House 13218 n 4738.5 4737.8 -0.7 242 4762 163,115,1 Sharpe House y 4738.4 4738.0 -0.4 22.0 4760 163,111,1 HS Land and Cattle n 4732.6 4732.9 0.3 22.1 4755 155,107,1 Karbowski Brave House n 4725.5 4724.9 -0.6 27.1 4752 145,108,1 Schmidt Well NA 4714.4 4713.5 -0.9 19.5 4733 132,112,1 United Well NA 4712.0 4714.1 2.1 33.9 4748 132,126,1 Owens Well NA 4714.2 4712.4 -1.8 33.6 4746 132,133,1 Wright House y 4717. 4714.3 -3.1 37.7 4752 135,132,1 Schmidt House n 4718.4 4716.6 -1.8 31.4 4748 135,135,1 Smit House y 4718.8 4717.5 -1.3 30.5 4748 135,136,1 IGssler House y 4729.5 4729.6 0.1 25.4 4755 148,137,1 Woolverton House y 47305 47305 0.1 31.1 4762 150,136,1 Shimon House y 4733.0 4733.3 0.3 25.7 4759 154,136,1 Kem House y 4733.8 4734.0 0.2 26.0 4760 156,137,1 Rainbolt House y 47355 4737.0 1.1 28.0 4765 161,137,1 Gilcrest Valley HS NA 4737.0 4736.7 -0.3 9.3 4746 170,155,1 The model was utilized to determine options and feasibility for mounding and shadow mitigation structures and are not final design. The baseline groundwater level is based on eight (8) months of piezometer readings taken at the site and further water level monitoring should be taken into account during design of the final mitigation structures. 7.0 CONCLUSION Civil Resources makes the following conclusions and recommendations based on the modeling: ➢ An underdrain or series of wells will be effective at minimizing the groundwater elevation rise south of the Site, and similarly the Gilcrest area, by removing water from the aquifer south of the site. The groundwater will be Groundwater Model Report— Section 20 Gravel Mine Site -14 - August 2022 collected in a manhole at the midsection line south of the site and transferred through solid pipe to an infiltration pond north of Cell 7. At full site buildout, including the Monarch DENM Site, the quantity of water to be piped and recharged to the groundwater table through the infiltration pond is approximately 6.6 cubic feet per second. ➢ In order to keep Mitigation Structures within the DRMS Affected Area Boundary, it is recommended that an Infiltration Pond be constructed to receive rerouted groundwater and infiltrate it within the property. The Infiltration Pond should be constructed prior to the construction of the Cell 4 slurry wall and the eastern underdrain or dewatering wells. ➢ If Red Tierra wishes to discharge to surface as described in Mitigation Scenario 1 Red Tierra will have to apply for an Amendment to the Reclamation Permit to add the underdrain discharge pipe to the Affected Area Boundary. ➢ The models and data presented in this report are based on eight (8) months of piezometer data collected at the site. Further groundwater monitoring of baseline conditions and after slurry wall 3, 4, 5N construction will be necessary for designing the size and invert elevation for the underdrain or spacing for dewatering wells. ➢ Since groundwater is expected to rise(mound) south of the Site the mine operator will continue to monitor the existing monitoring wells in accordance with the Groundwater Level Monitoring and Mitigation Plan, included with this report, to catch any mounding or shadow effects at the Site before it become an issue to the surrounding properties. 8.0 BIBLIOGRAPHY Anderson, Mary P., "Applied Groundwater Modelling, Academic Press Inc., San Diego CA, 1992. Bishop-Brogden Associates Inc. & JVA Consulting Engineers, "Dewatering Improvements Study for the Town of Gilcrest Colorado," 2016. Colton, 1978, "Geological Map of the Boulder, Fort Collins, and Greeley Area, Colorado," U.S.G.S. Map I -855-G. Das, Braja M., "Principles of Geotechnical Engineering, Fourth Edition," PWS Publishing Company, Boston, Massachusetts, 1998. Fetter, C.W, "Applied Hydrogeology Third Edition,"Macmillan College Publishing Company, New York, 1994. U.S. Department of Agriculture, Soil Conservation Service, 1988, "Colorado Irrigation Guide." Waskom, 2013, "Report to the Colorado Legislature Concerning HB12-1278 Study of the South Platte River Alluvial Aquifer," Colorado Water Institute. Groundwater Model Report — Section 20 Gravel Mine Site -15 - August 2022 Figures -tyi a'I. .3.il1lnl�' ; -4 yii'• f:•'' •� / • ) 6 ti,. •.'+4PSON 7'11/4- `�w�.•� - f ••• u ,, ��I p____ J !a -cum *lc 3. ,.aAVEI Km - I to I GRAVEL NINE] i- 7.- I.•• - i1/41 tit I • • rte% • ., �'. F - :1,' 1 ./�•- A�1 p 1 \ ► f / l'f 'I r - J 1 1 I ! 1, I �t La ._ \ 't • I I i ll �� '' �1Lfw..•�'`( I I I I� I,�y�l I! fy'►r .74.. t. - w .-+•••y / I .ikkC.FE-T t7 • I 1 Ira C- • 1 - I` " _See -s• -k; MOM BOUNDAAI v �� G •1F- .w. 1 14. 6 Off, - LA 'ALA 4.1 1 I 4. I 2 Jf+% '• t. t \ 1' y, art trvi. BEDAOCX CONTOURS SOURCE WELL moms AND BORE LOGS (SEE APP£N01■ twctil • i• f a S. M • 't ` ` \. \ ` ".\• \ • - 011 LO'NEa unto, 'k . aiSEavOfA ., -r,► -mot "!_ 4E: I - 0pc r. /I wervelwime • mill Ilast1A illthellll Call sun you dig. C IVII RFStURl, 323 SID STREET P.O. Max 680 FREDERICK. CO 60530 301.8 13.1416 W WW.CIVILRFSOURCES.COM RED TIERRA EQUITIES, LLC •101 t, NENTIQ AVE 4 DX GACHIV4000 VILLAGE, COACI:: GROUNDWATER MODEL SECTION 20 GRAVEL MINE GILCREST CO RtVLSIOWS NO DESCRIPTION DATE CESIGNMC B' to DATE 1'LG-se. COVEN 61 Eist SCALERS CEO C taED t'' MS AS NOTED MIS DO. )Q1.OQI.CA LWG NAMt OW kWh 1G I1TTi22 REGIONAL BEDROCK SURFACE 1 .Rat 80UNDARIT SOUTH PLATTE RIVER HEAD AND RIVER SEC BASED qN VSGS TOPQ CDISIPCTANCE 15C -1a INCREASING DOS'TREAM AS RIVER WZEJ i V1Y • t nAJ%•.iE PONi.> RATE C.012 AtiDAI 413 ANNUAL RECHARGE 1.677.4 ACCT INTERNAL 80VNCAM I C0NDlTION RIVER - WESTERN MUTUAL DITCH CONDUCTANCE UPSTREAM E FT/DAY DOWNSTREAM 2 ET/DAY ;!4 mot kt "•..lC PATE L.CE7 FT/Cat Kill ANNUAL PEiHAR .+ 122.8 Aral - DATE HUNT RECHARGE KINDS PATE U.0 IS Fit DAY ESTIMATED ANNUAL RECFMPGE HAREM RECHARGE POND RATE 0,u1)S PT/DAY 2013 ANNUM RECHARGE 1.:60 AGfT INTERNAL 8CRINWUY CONDITION RIVER • PLATTE VALLEY MO4 CONCUcnAPDE 3•S PT/DAY APPROX. I0BELOW sURFACE INTERNAL $OUtIOAAY CONOmON RIVER • EVANS •2 Ct7PI0UCTANCE )•S MEGA, 1 P H RISIl.Itl 323 Stn STREET P.O. Box 680 FREDERICK, CO SOS it: 303.8 33.1416 W WW.CIVIIRESOURCES.COM RED TIERRA EQUITIES, LLC •101 E. PRENTICE AVE .100 GREENWOOD VIuAGL. CO Ma 11 REVIsiONs DESCR1PITQN DESIGNED SY. Eat „PTE 14;i- Astir. antra BY ESL. SCAL2fS NOTED to Ski. PPS NOTED JOB NO. MAOI.CA DWG Mt_ GW MODtL U I12t,Zj,onq_ BASE CONDITIONS J I ,QAVFt MINE 1;: i l,;("1' SEC110N 2C GRAvtl MINE 71Y F4/) 120 P7/0 towt* MThot VC4110 ae�nolll 001100 b s9. 323 5th SIREER P.O. Box 680 FREDERICK, CO 80530 307.813.1416 W WW.CIVII RESOURCES.COM RED TIERRA EQUITIES, LLC •101 E- PRENTICE AVE 110C GREENWOOD VILLAGE. CO KC111 REVISIONS VCIOU iT:QN GRTr [Alt WALLAS NOTED A4 NOWED LWG 1MMtflj4ODEL IC112012-awn HORIZONTAL HYDRAULIC CONDUCTIVITY 3 NW2 OBSERVED. 4711.2 MODELED 4717.9 MW -7 OBSERVED. 4728.9 MODELED 4724.9 WIEDEMAN HOUSE MW.) MEWED 4725.1 MODELED 4724.9 WADING NOVSE FM -S OBSERVED 4736.4 NOMAD: 4735.7 INFILTRATION FORKS 323 SIn STREET P,p. Mx 680 FREDERICK, CO 00530 303.833.1416 W WW.CIVILRF:SOURCES.COM RED TIERRA EQUITIES, LLC 63CI E. MEN! ICE AVE l IC0 GREENWOOD VILLAGE, C01C211 DESCRIPTION CESIGNEO IV GA DAZE /•6.21.22 CRAWN 6+ d$L. iCAiE9S M07ED CrECKED BY as. AS ACTED EXISTING CONDITION CONTOURS 4A Know. who., below. Call hears you dig. Cc„ -- IL II NFS11112t I' J23 MM STRWEI P.O. Box 610 FREDERICK. CO S0SJG 1O3.533.1416 W WW.CIVIIRESOURCES.COM 0)01 E.KIWIICIAVE •100 GIIEUAV000 VILLAIN'', CO eC I !I OESIGNEt T' j p&IE /•2O-2GiL OQAWN et as. sc*uhi tor to crept to Or X121 AS NOTED IC* NO. )0 )-V41.94 owa 4aMt. j MQOtL 1fi1120t2.Gsa EXISTING CONDITION CONTOURS 4 1WIEDY, FUJBPAVE HOUSE -0A' SHADOW WM)MARCM DE GRAVEL MI MS LAND AND CATTLE 2.3' MOUNDING SECTION 1C GRAVEL MINE W[EDEMAN MWSE s.1• MOUNDING - :AMC WELL •S.) SHADOW CELL ss MODEtzo SLURRY MALL LDCAtION WIEDEMAN (OUSE Si MOUNDING WADING HOUSE 6J' MOUNDING CLINE HOUSE 7.7 MOUNDING SNIT HOUSE .O.7 SHADOW i .=. WOOtvERTON HOUSE 4.6' MOUNDING KERN MOUSE SA' MOUNDING tear IVA" +- --c .. what's bRIOW. Cu Woe lou dig. vII WI`, TTli 313 SIN STREET P.O. Box 680 f REDERICK. CO 80630 303.833.1416 W WW.CIVII.RESOURCES.COM RED TIERRA EQUITIES, LLC 6101 E. PRENTICE AYE + LC0 GREENNOOO VILLAGE. CO ECIII GROUNDWATER MODEL SECTION 20 GRAVEL MIN GILCREST CO 0.! vLS:GNS 'NO, 5EUT 0TfON DATt DESIGNED ST 1 DRAWN 6Y 1L`a8. CnEOLED 6r 1Ltt IOC NO. 10).001.L4 DA)E 7.20.2021 SCALERS NWI,0 at$711.0 CWO NAf1E.ett.MODEL IC112C22.Abo SLURRY WALL FULL BUILD OUT CONDITION CONTOURS 5A L: I 323 5th SIREEI' P.O. Box 680 FREDERICK. CO 80530 301833.1416 WWW.CIVRRESOURCES.COM RED TIERRA EQUITIES, LLC 8)01 E. PRENTICE AVE Imp GREENWOOD VILLAGE. CO icl 11 MOUNDING SHADOW MODEL SECTION 20 GRAVEL MIN GILCREST CO REVISIONS NO DESCRIPTION DATE ,:.NEC DY JS5g DRAWN et 65k CHECKED DV WI Jon NO. Via] lsc4 DWG NAME GW EWE__'41i202t.6ra Dan /-.‘.-,ti;t2 SCA EAS NOTED 45 NOTED SLURRY WALL FULL BUILD OUT CONDITION CONTOURS 5 Ill HS LAND AND CATTLE• . O3 DROP ' WIDERCRAIN J I J 4 SLOTTED PVC 1014004 CUM UNDERDIUMN ' GROUNDWATER ,, FOtIFCYYATEA E 34 CPS 1 REMOVAL RATE 3.3 CPS I S , RATE 34 CPS - i ' IMV !L ♦ 3 L' 4um me 1 i t..L! i >ei 1 . lit me in in a MANYOLE DONNE( I iOt i J Nph/ERtORATE0 PIPE .r....be.....r•.s.................../ .. UNDEIIORAIN INV EL 4715' CONSTRUCTED WITH CELLISW WIELIEWW (OUSE OA' DROP UNITED WEtS 5,7 DROP MOORED DEWATERING WELLS; OR UNDERDRAIN1 GROUNDWATER REMOVAL ).2S CPS ODNSTRUCTED WITH CELL 4 SW WIEDEMAN MOUSE 1.Y RISE OWENS WELL 44/ DROP MODELED SLURRY WALL LOCATION HARUDIG HOUSE I. J' RISE WRIGHT mouse 6.31 DROP CUNE HOUSE OS RISE SCHM1Cl HOUSE 1.: DROP SWT HOUSE 2.T CROP WDOLVERTON !OUSE 0.1 DROP snow' tease L.1' RISE RERNFOUSE 0.IRISE .I AIISOLT NOVA 0.1' RISE GILDER!, VALLEY HIGH SCHOG: DS DROP 313 5th STREE P.O. Box 680 FREDERICK. CO 80510 303.833.1416 W W W.C IV ILRESOURCE S.COM RED TIERRA EQUITIES, LLC I )D 1 E. PRENT ICE AVE 8 100 GREENWOOD VILLAGE, CD RC 111 NO REVLSIOAS DESC-M►P.ON DESIGNED nY ,✓�,'g OAR I•A_4G22 DRAWN IT Ka SCAIEM_ 1WD-- CHECxED IT NIL AS NOTED Joe NO. )03.001.04 C.WC NAME GW NOOEL IC112➢22am SLURRY WALL WITH DRAIN CONDITION CONTOURS 6A MODELED UNOERDdWN IOCATUQN 101Al WATER REMOVED 1,1 t0Y CONatRuCTED MTN CELL 6 Sw C₹WAtflRtNG MISS LOCATION APP00111MATE TOTAL WATER REMOVED 131 CPS COUNT I& M..& WITH flu 4 5W c CIVIL RL 323 5th STRUT P.O. MR 660 FREDERICK, CO !0530 303.833.1416 W WW.C1V ILKESOURCES.C.DM RED TIERRA EQUITIES, LLC 8301 t. PRENTICE AVE 0100 GREENWOOD VILLAGE. CORGI I I MOUNDING SHADOW MODEL SECTION 20 GRAVEL MIN GILCREST CO ' I VIMOM bESCAIIfiO t� DATE DRAWS ST a& CNEDIED OT DLit _ 100 NO. 301.OOjseA cwG NAMEGw MO Q1. :y, laul.0wa DATE 7.24:cu 5CALtelt NOTED A5 NOTED FULL BUILDOUT WITH MITIGATION 6 `=`-7 i- - •.: ` / -:_?jC . - ,�-= r: q:' STEEL WELL LOOKING 6D.c SC7MIDT WELL yrAy1s.0 -lD.o-1 LID -BASEHfAOEI t11/.t - _�'� ety.. . — CoreTITI:MITIGATION HEAD EL 4713.D TT ,DROP'. 1.1 OWENS WELL BASE HEAD EL./71/.2 :G- le I SLURRY WALL PLATFORM I —__.'' .._- _ _ If '. _. -• Et.t71).t - PlTl2'55AOAPTER T10NHEAD ' 3C A�� ' f��o DRO _ .4 _ lo.c ( I V I I It I. 5 mil:., , � VARIES y r illfr -- ' r - I I MINEIREC7APLATICIwt 323 Sth STREET SLOPE 1� _ _ 1 �, P.O. BOX 6B0 1 FUTURE SLURRY WALL /. FREDERICK, CO 80570 2t' PVC UNDEROMIN .r J03.833.1410 WWW.CIVIL 1 - 5' DRAIN MANHOLE OPEN BOTTOM WITH AGGREGATE BECCM, - - RESOURCE S.COFt A7 UNDERDRAIN TYPICAL SECTION +0.5.131 v a 3t' DIAMETER �- g O.)7S• WALL 1HICKNI 55 5T0 1 r� llllll „ STEEL S•NG CA �.�: 1 I NM GM MI 1N — ass — a fn Its a us_ r se _ 5 a a a MN .03 • 13 I 1 t _a ti -� - 36 CUMETER BOREH(ht FOR S,4 _ _ . N REi7MRGE UNOERORAIN ;- 24' RECJI+LRGE UNDERURAIN .- InrEL♦r27_la I EXISTING GRADE ; F 1 1 tie/ El472T - I� I ] f1-- ` �'• / RED TIERRA EQUITIES, LLG ' '-_• CM)I 11 _ ; ll=-2ir III I 1141 �I4c '1 e. - B)D1 E. PRENi2CE AVE t WO clt� i,•( P GREEMY000 VILLAGE, CORM! \ • . ---- \ •T •Ipa I - - • �aimum".• ' BOTTOM I 1 , . _ 1 I _ ; .1 _ .. _`_ - STANDARD MCD PER AS1M 11698. JJ. r hit)+0.5 I 'STD - IS" DIAMETER O.I75 WALL TTQOD2E55 ^k 1 '. - -. ' T iACI4G WIRE • �' CASING 15 1 BELNTONItE MUG I — - 12••24' PERFORATED PIPE / 1 • I t$UBMiT ML REQUIRED; I .' _ SECTION 20 1 ' I / 1 GRAVEL MITE . ` • - - 1 J - - - • - - ' •B ROCK APPROVED ' 1 . SOUD DISCHARGE PIPE BY ENGINFEA ANC • _.. ' - - • DELIVERED BY OWNER. n C t 1 G 1 UNDWATER MOE [ON 20 GRAVEL GILCREST CO I II 1 1 , g UNDERDRAIN TYPICAL TRENCH SECTION 1 I I _ t m IQl1 _ { ( I 1 1 •. •p S•• a in e e -•••.••• On I I ' 1 I • s . L I I 1 1 t ; 1 !' 1 1 • 1 • • 1 ;-• ••' • 11 • 1 . 1 11' 0.150 -IN SLOT STAINLESS I ' I •.••�•ys•••••.•• STEEL .304 WELL SCREEN I ` � •• 1 J 1 • I i vARIABLE I II ;• FIIEQVENCV I • DRIVE/ _ TS ECONCRETE Cali ANCHORTED 1 PAD IG' DISCHARGE LINE I 1 . START BOXY 1 / 1 I 11alliMilleigailli-1 i 1 1 REVISIONS I 1 24 OIII RIR tt' Dl9avu,,. 17.0 I I I NO DESCRIPTION DATE 1 Mro�RotFw n'uMF�(o4 1 CI%OON 1f.3 c. ; ,' TAU 10 - APPRORLEVED .f =+, EQUAL) 1 •' E 111 _ + I l� PAC( I_ )'-6' GRAVEL FA w•_ 1 , • —' ... ' �!°M•r' 1VP. i 1 1® - TPA•-�" I _ IAMB ME Me BIN or - a _• - _ `\JJ _'rte _ 71• J L `� _ I VV • • t _ CEWATERING PUMPS - OR UHOERDM2N - - D:SOMifE).S CPS _ CB SUPPORT BRACKETS ANCrpRED IN C.ONCAttt PAC VfD OR I' ', MANUAL START - �•• id 10 SUMP - s - BV DATE-J-20•t4AL - ..- --- l•• - CESIGNED !(40. `-`� CMWN IV a SC.ALEAS NOTED - CHECKED BY s AS NOTED , - 108 NO • 1.0111.41 NAMEL CWG W tath IG112G22Ana_ • y STEEL BASE uLDED r� 1. [J SLURRY WALL Mil 10.OIP If ( r L.) 4 J DRAIN WITH ■ "ps/1RECHARGE V - OW tatEXC EPT ON BURIED _ \ / UST WELL tNSET! D4(CK D DEWATFRING WELL WNW 2(IIOYP Y.'11tl11 U6Pll�1.• - _ Call before you Mu. - - 1M +Qtl UEWATERING WELL DETAIL _.-- 7 l 7 k ,,,------ -______________ 1- r --;>" '<.:.-.7-' I 1 IL-------:<:---, -------______.>, . _____ i_____,>: 'V ~'- ___--1- a C R 4 4 I L -a, - - - _ - - _. t �_�--_1_-it- i , _ - --I-H_1_ lf }I I 1 f' fi I I_i CELL j I D :1 : ri 4 i 1 - ki I 1 ti I 1:11- 11 t1 I I I I ___� I I 1--)14- y-I-t---1---i-ri--1- 1 1 —pier- -fr-÷ --/i--1--f-i- -f-- -in --i- II-+- 1 il + 1 i 1 +�h_ e• I I ( � 1 SECTION ZO_1__4_ i H ---1-4M0NARCH - + II D T I L_ I ri -( ___Litriart_hiENM �- �- 1 J _tin I I4 Err., 1 t i--(it T---1- WCR 29 I J I -�- - T --r 1 t T--- T- I-�- I III ■■� -- �1 W C R 42, - - - I - �.-. ft WESTERN MUTUAL DITCH i -- ____A----- _ c �' sIN `� i I WCR 25.5 74 5 - --- ---�. � �� ii �� ■■■ ■ill■ Lin IN NF;FT NOTES: 1. THIS MODEL ITERATION INCLUDES A SLURRY WALL AROUND CELL 3 2. NO MITIGATION IS MODELED IN THIS ITERATION r RED SECTION TIERRA 20 GW EQUITIES MODEL � DATE-_ FIGURE: HEAD CONTOURS WITH Ortatherr, 1110228 CELL 3 SLURRY WALL :,.___,, �.. .Vi -± I ± L WCR 44 � ... , 1 i I _AL. JI LI ;" I I( I I -1----�- ( _ CELL r ,/, I In I -11-I4:4_ + -I-, 1 I 1-�- 14-4 5 Ira T 17 2 i i 1 h�-� 1 f l I( N !! I fi I I I I I 1' I 1 I 1 SECTION 20 CELL 4 , 1 �_� � ► ��UtH1i1 IC 1IIJ _ TO 1 ! ll I I I X. o f I- , DISCHARGE I SLOUGH I I I I 1I'llii III��.�.__,__.� ii --r ..—raril -4:-4. -�-1--i_ __t_ — I !-_-1 �! - I I■ ■ ■■■ IIIUI I-� MONARCH DENM If I I -4 4-- --1.4-4- • GRAVEL MINE _� !I ■■■■■■■■lI / r I • ■ �� - ��■� / ■1 I LI)'�.4' +44_1_4+1 1 I MW -b MOUNDING' ' • A , lik -1---` cn +orr-- Ill li r -J - --1--1- (AEta _ i--I-- I -�- ■ ■■■■ I ,..,_ _=_; --fr-ri . .......--- - alai E I - UM Heil ■� a�Or �■ IIII - All _�� _ 1! ■■■■■■■■■&■i�■ ■a�■ii�■MI�i■�■�,■s■r■■■■1 - ma! 2 ■■■■■■■■■■ ■=■■� ■1 le P,�■■■■■■■I UNDERDRAIN DROPS INTO India :! a I Min ■■■■��I_■� - ■ - S DIAMETER MH ■■�■■■ MW ■■■■■■■1 -...11. " I'■■ ■■■ice. I ■■■■■■■■ 0.4' DROP II ME _'. �,,� Pa■r■■s■■ ` ail EMI 4740 i7 ■■ UNDERDRAIN 11■■■■■■■■I III III �■M■■■■ - a.■■■■ _ ■■■ DISCHARGE24 S ■■■��■■■■1 — - ■■■1 --- s - -■� OR 174,000 CUBIC FEET/DAY Is.■■■ ��Ci ■■II_ WESTERN MUTUAL DITC ■■■ �. - ■M■■II ■■■I 1 I M ■■■■■■� _-I -t-- I i �■■�.r■■■■■■■r ■■■ ■.■■■ ■■■■■■■■■1 ` MONARCH ■■��■■■■■■■ �■■■■■■■■ � � ■■■■■ ■■■■I a I ■■■■U■■ �`� ■■■■■■■■■1 CELL 1 /■��■■■■■■� ) ■■■� Az NM Ell _ _ _ �■■■■■■■■■ _ ___■■■■■■■ ` - ii 1 Ens ma ■r a r ■ ■IIIIIIII_ ■■■■■■ ,�-. ■ ■■■■■■■�■■ 1 1 in WCR 25.5 aI I $ 1 MI All ■ir/ ____ ■■■■■■ ■ ■■■■■■■■■1 _ . - All III 11 Pr-rlenmen. ■■■� ■■ ■■■ ■a niii, \m... NOTES: 1. THIS MODEL ITERATION INCLUDES A SLURRY WALL AROUND CELL 3, CELL 4 AND MONARCH DENM CELL 1 2. MITIGATION WAS MODELED AS AND UNDERDRAIN DISCHARGING SECTION RED TIERRA RRA 20 GW EQUITIES MODEL 2 CFS OR 174,000 CUBIC FEET PER DAY TO THE UNNAMED SLOUGH WEST OF THE MONARCH DENM SITE. DATE FIGURE: HEAD CONTOURS WITH . itil122 9 CELL 4 SLURRY WALL J I I 4 4 —r "----------,..„ r4 ., ___ . I 411,// -.-------------*-------"----,_,,,,---H>_,,,.., * .7 --- c._ --,,___.. 4 1-- ��' /� / _'�- jell,1i t+i- W I M+41_j :R ( I 1 1 ti 1 I 1 J I! i Q� `' `, I 1 ,I 1 I I 11 _,4� : CELL 3 I i I �' i d �� i 11 I I I i� I I I I J 1 1 r �i I . [i-i 1 irt1111: • 0 I- H7-i l I i f J III _I i t 1 1 CELL 4 (` SECTION 20 I I I . ,I tfri-lrir-tr- DISCHARGE Ut+_+_L_LNNAMED I I till;ii i �� i I f I -r+ ---TO 1 I C41 H4I 3SLOUGH Ii:Irli 1 -1 -1- �. I i � { I I T I i f + -4 -+�- MONARCH DENM I I I CELL SN - III I , 4 A--I--�--+--A GRAVEL MINE Stijl , [I li I, I ill -4-4-4 I ,}- ii j t � �1 1 IiIH I 1 0.9 DROP tiI 1 ii fri . lilt! MW -6 J � III �� l l I ■ f� ' 0.2 RISE �■ ■�■CC `�' �J �, ,� 1-1- t 7. 1 ,----- L. 1±.fj-e,___E. ■- -rr �� ■.■■�r■r as -4 O ■�■ 42 - III->-_-- -I _ J _____ ‘ ± ---, 1 _WCR ,., Li ______ , . 1 .__ - .->._ / / �-_ _ i:-.6 l 3 DEWATERING WELLS ,_^ = `� to 2.5 CFS -- -- �. TOTAL DISCHARGE -- WESTERN MUTUAL DITCH OR 216,000 CUBIC FEET/DAY / � ._.. I _ _ , MONARCH �_ _ _ ,' '� CELL 1 I c. �` Lim CZ- ter. ■■■■■ ■■■ ■ 1 _■■■■■■ �� ■■■■■■ ■■■■ ■■■ ■■ 1 _ . _ - 4150 �1� r, ■■■■■■ ■� ■■■■■ ■■■ ■■■ ■r _ : NOTES: 1. THIS MODEL ITERATION INCLUDES A SLURRY WALL AROUND CELL 3, CELL 4, CELL 5N AND MONARCH DENM CELL 1 2. MITIGATION WAS MODELED AS 3 WELLS DISCHARGING r RED SECTION TIERRA 20 GW EQUITIES MODEL 2.5 CFS OR 216,000 CUBIC FEET PER DAY TO THE UNNAMED SLOUGH WEST OF THE MONARCH DENM SITE. DATE: October2022 FIGURE: 10 HEAD CELL CONTOURS 5N SLURRY WITH WALL i r I ■ I I► ► 1 I, ■ ■ t I ---- Tilff_r I l rt++.1- ---F 4 4_ --- 1_ 4_ 4_ 4 -I: i — $ I I I --t- -t- -t-- _I rj-t++ J t Ii -1-1- -I -t- I �--� —t —t t t r -r _t — irl— irjel-1 . [-I I : t i 1 i I i , __A_ I i ..,- 't Ifr crieri t 1 -r- I I 11-1 -I- _4_, . I 1 I I -1-- -t- t- pv- ' -4-- r -I— 1 I t —t— 1 1 _S____ --hi I --H-1-1 L—.— c___.4..___ IL I I lir 5--E- t- 1 I I j 11-1— I I -I ....1±-, I i lilt I I ' 3 1 ,k, 4--tairell4; ÷i-±"Irlacl-4e1----FirSa- .:-....-.. tir I _4_-_ 1-7, a ---- , a 11? i II -EMI* --1-1 • I II I I' CELLS i1,1 I fi I,I i. F ' ris-1-1--i-P ....,. 4725 ll 1_1_1_, + MONARCH I ! / �� :� �i ■ rt "1 .� CELL 4 l P .. '1 __ CELL 4j■I ► �r r CELL 7 - - SECTION 20i'l -+- -#.-f- —I- -�- --}-- 1--I- I-cxo I ill ---4- I , IJ J J I �._ i 1 ...� .. --�- __ ___ -4- p , - _ , _ _ 4LJ_____1-- l i -4-_ i -� II �- . ,�-f-- MONARCH DENM ' I ' CELL 5N ' ■ i , GRAVEL MINE.0' -�4i- �_� r : : ; , i ■al ,r r �__I -t-- t II L_-- --- _+- ■ U1 CELL6 - - /�., -4—�—�(� I { r I ■_'■ ■�' r I I __. 4___I . ,.� .- _.. 1 ii giror MONARCH ■I I ' _ �i —Ivorr CELL 3 r'y ..i� `jam �..�� CELL 5S 1 � . a��s ■ t.. _- ��_ �,, , �■■■■ r 01 11 //, .: iii ■ i■i i . 11 _�i■ ■■■■■■■ ■�■■■■ �o ■ ■_■1 MONARCH �i "..,� ��,�... _ _-- ■N �� ■iii �e ■■�� .. � CELL 2 ■■■■ ■r■ M ' 1 HL ��■■■■■ ■■ ■ ■■I MONARCH ■■■■■■ ■■ ■■ I'� CELL 1 ■■■■■ ■■■■■■■■■ ■� ■■■■■ ■■■ ■■ :.are■ cNCD C , NOTES: 1. THIS MODEL ITERATION INCLUDES PHASE 1 WITH RECHARGE MITIGATION RED TIERRA EQUITIES cn SCENARIO WITH SLURRY WALLS FOR CELLS 3, 4, 5 AND 5S CONSTRUCTED, THE MODEL °a INFILTRATION POND CONSTRUCTED, AND THE MONARCH DENM SITE THROUGH CELL2. --- - SECTION 20 GW 1' 2. 3.25 CFS OF GROUNDWATER IS COLLECTED FROM THE SOUTHEASTERN END OF DATE: FIGURE: PHASE 1 WITH SECTION 20 AND DELIVERED TO A MANHOLE, WHERE IT IS PIPED TO AN INFILTRATION POND LOCATED NORTH OF CELL 7. December 2022 11 INFILTRATION I, r g , g I 1 . - 4 I 1 t_rittr I I I -- , IIIII,_If -r 1111-4 +��t r I �� I r _1 ' � I `— —�—•—T r I 1— t— —� h i I Tr —‘--1-1 — I- I 1 -- .,, ' 4_t ' ! \N � 1— / �-1- : —: y _...t _T. -;-- ii - I I 1 —j— -T— 4 r— r-1---1-- :-- -4,— --T : ---r ± t el t -L--4. I _jaI4 -I - / _o_ + irair .1_ . 1 /I Iii.. II �� . r "� ` \'j�� ,� 1 �.1. 1 Slit rtir4THIrj"1 r r ...1 1 _i- Lil 1 I I ■�i�.:,:;; CELL 3t L 1 _. Ir t t 1 I I .I �. ~I � � I I ITr r II t INFILTRATION iirns. / MONARCH I i PONQ I a- ti I I CELL 4 ■ fI CELL 4 }, i_ CELL 7 SECTION 201 I 1 ti&8 I t- tI t I J i I MONARCH DENM L i I, I CELL 5N t I - SOLID PIPE ' GRAVEL MINE t j I '■'� T-- I I I I _J CELL 6 I4 —t--� I' ____� II t I _ _ . 1 fi MONARCH t t 1—ced � ICELL3 t t CE L L 5S - � F k_• t t � � � f I I t ,. 4735 Ill /e `:, i t r - �� ■■■■■r ►�� _ I J �r J- �� f. . �A / ■■�V■ ■ iii : ■-1�■ii■ L. .1_, ;4i } ��■�, tl\� rl I��ii■■■■■■ :. , !.■__ j .��..�.. �( �. MONARCH _ L'li CELL Z t ■■� M N H �► t ■■■■■■ �ni ■■ �I L 11 I -- ..._...._ .. ..% a. -Mr-- • 4 lisil ... .: MONARCH _ ■■■ ■■ �---� CELL 1 Y �1!!! ��■r��u`-cti __ �■■■ -ter � ■■■■■■ - et -wic> r . v NOTES: 1. THIS MODEL ITERATION INCLUDES THE FULL BUILDOUT OF SITE n SLURRY WALLS IN ADDITION TO THE FULL BUILDOUT OF THE MONARCH DENM °es SITE. 45 RED SECTION TIERRA 20 GW EQUITIES MODEL 2. CFS OF GROUNDWATER IS COLLECTED FROM THE SOUTHERN END OF THE 6.5 SITE AND PIPED THROUGH THE MIDDLE OF THE SITE AND DELIVERED TO THE INFILTRATION POND NORTH OF CELL 7. DATE: December 2022 FIGURE: 12 & INFILTRATION FULL BUILD -OUT POND EXHIBIT G — WATER INFORMATION This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.4.7 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Locate on the map (Exhibit C) tributary water courses, wells, springs, stock water ponds, reservoirs and ditches The site is 0.4 miles east of the South Platte River. Please refer to Exhibit C for locations of water courses in close proximity to the site, including wells, springs, stock water ponds, reservoirs and ditches. (b) Identify all known aquifers The site is underlain by a shallow alluvial aquifer, typical of its position upgradient of the South Platte River. (c) Show how water from dewatering operations or runoff from disturbed areas, piled material and operating surfaces will be managed to protect against pollution of either surface or groundwater both during and after the operation. Please refer to the Mining Plan Map in Exhibit C-5 of this application. Mine areas will drain internally. Uncontrolled releases of surface water in disturbed areas will not occur. Stormwater collected in the active mine area will be managed through the dewatering system. Dewatering will be accomplished by digging a sump, generally along the base of the mine slope, which will hold a floating pump. The pump will have an HDPE discharge line that will be routed to one of the comingled discharge points located at the site. The pump will be powered by a diesel generator housed in the active mine area. The Operator will apply for and receive a comingled stormwater and process water discharge permit prior to dewatering at the site. (d) Estimate project water requirements including flow rates and annual volumes for the development mining and reclamation phases of the project. Water needs estimated below provide for sustained production as detailed in the Mining Plan. The Operator will adjust water supplies to account for actual demand, avoid waste, and continuously comply with laws and regulations of the Division of Water Resources and any other water agency having jurisdiction over the operation. Projected Use And Consumption: Annual evaporative depletions will be the evaporation from up to 5000 feet of 4 -foot wide de -watering trench, located inside of the slurry wall. The total area of exposed water is 0.5 acres. The gross annual evaporation at the Section 20 Mine is 42 inches according to NOAA Technical Report NWS 33, Evaporation Atlas for the Contiguous 48 United States. Monthly evaporative losses are determined using percentages specified by the State Engineer's Office for locations below 6,300 feet. The nearest weather station is in Longmont where the average annual precipitation is 15.08. Effective Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G -1 precipitation, that part of historical precipitation which was consumed by native vegetation on land to be covered by water surface, is conservatively estimated to be 70 percent of the total precipitation. The annual average effective precipitation at the property is estimated to be 9.09 inches. When subtracting the effective precipitation from the gross evaporation yields, the net annual evaporation is 31.44 inches, or 2.68 acre-feet per acre. The Fresh Water Pond is approximately 10 acres and the Siltation Pond will be utilized in 10 acre stages. The approximate acreage of open water surface is 20.5 acres. The annual amount of evaporation from open water surfaces is 54.9 acre-feet. Mining Production & Operations: The Operator expects to extract approximately 2 million tons annually of aggregate material from the site. All water retained in the recovered material will be replaced pursuant to the Substitute Water Supply Plan (SWSP). The total annual amount of water retained in the gravel product from mining activities totals approximately 27.2 acre-feet. The SWSP is renewed annually and will reflect analysis of production and depletion anticipated in each year of operation. In addition, an estimated 4.0 acre-feet of water per year will be used for dust control based (approximately) on 5,900 gallons per day for 5 days a week for 10 months. Annually the total evaporative and operational losses from mining activities (open water surface evaporation, water retained in the aggregate product, dust suppression) totals 86.1 acre-feet of depletion which must be augmented. All depletions were lagged to the Saint Vrain River using the lagging factors approved by the State Engineer pursuant to on -going Substitute Water Supply (SWSP) approvals. (e) Indicate the projected amounts of the water sources to supply project water requirements Replacement Water: The Miner will obtain an approved Substitute Water Supply Plan from the State Engineers office every year, providing annually or more frequently the opportunity to review the sufficiency of water supplies. The SWSP approvals require that the applicant provide a detailed explanation of the mining operations, a quantification of all mining activities and subsequent depletions and all legally available replacement sources. (f) Affirmatively state that the Applicant has acquired or applied fora National Pollutant Discharge Elimination System permit from the Water Quality Control Division The Operator will apply for a National Pollutant Discharge Elimination System (NPDES) permit from the Water Quality Control Division of the Colorado Department of Public Health and Environment prior to discharging water from the site. Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 2 Groundwater Sampling and Analysis Plan This information provided in this subsection of Exhibit G is intended to satisfy the requirements outlined in the Groundwater Monitoring and Protection Technical Bulletin dated November 19, 2019: Existing Groundwater Conditions The near surface groundwater is part of an alluvial aquifer in which permeable sand and gravel alluvium overlies relatively impermeable bedrock of either the Fox Hills Sandstone and/or the Laramie Formation. Groundwater, measured in 7 piezometers, occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the site. The prevailing groundwater flow at the site is to the north reflecting the site topography. Groundwater in the area is tributary to the South Platte River located northwest of the site. Locally the groundwater levels and flow directions are likely influenced by: ➢ The South Platte River is northwest of the site. For most of the year, the river likely acts as a drainage way maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the site under the intersection of Weld County Road 42 and Weld County Road 29. The ditch may act like a drain during the non - irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ The Farmers Independent Ditch traverses the southeast corner of the site and bisects Cell 5a and 5b. The ditch may act like a drain during the non -irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ Irrigation: The site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration likely recharges the groundwater. ➢ Alluvial wells: Other than the seven monitoring wells drilled at the site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the site, two wells east of the site, nine wells south of the site and one well west of the site. If pumping, groundwater will be drawn to these wells. Red Tierra Equities, LLC — Section 20 Mine — MLRB 112 Permit Application Exhibit G - 3 Potential Slurry Wall and Mining Impacts to Local Groundwater Levels For all lined cells, a properly constructed slurry wall will tend to isolate these cells from the surrounding alluvial groundwater table. The liner around these cells could cause "mounding" of groundwater (increase in groundwater elevation) on the upgradient side (southeast) of the lined cells and a potential "shadow effect" (reduction in groundwater level) on the downgradient side (northwest) of the mine. Because the liner will tend to isolate these cells from the surrounding groundwater table, the effects of dewatering when mining lined cells will tend to not extend beyond the liner. Any mounding effect on the upgradient side of the site (south and southwest) is anticipated to be on the order of a few feet or less and will dissipate with distance from the mine. Similarly, shadowing effects will be on the order of a few feet and will dissipate with distance from the mine. The shadowing effects will be minimized by the presence of the South Platte River to the northwest and the Western Mutual Ditch that runs between Cells 5A and 5B and the Farmers Independent Ditch which runs southeast of the site. Dewatering of the unlined cells (Cells 1 and 2) will result in decreases in water levels around these cells. Since there are no wells permitted within 600' of the unlined cells, the effects of dewatering the unlined cells will be minimal. Area Wells A review of the permitted wells on file with the State Engineer's Office (SEO), Division of Water Resources (DWR) indicates that there are nineteen permitted pumping wells within 600 feet of the permit boundary. All of these wells are screened in the alluvium. None of these wells are within 600 feet of the unlined cells (Cells 1 and 2). The well locations and applicants are shown on Figure G-2 attached at the end of this section. Groundwater Level Monitoring and Mitigation Plan Dewatering during mining of Cells 1 and 2 is unlikely to affect any wells in the area. However, if the miner receives a complaint, the following mitigation plan will be implemented. The site monitoring wells will be measured monthly to identify potential changes in alluvial groundwater flow or elevation associated with mining and reclamation activities. Baseline data will be collected prior to dewatering or construction of the slurry walls. Baseline data will be collected from the monitoring program will provide a range of relative water levels associated with pre -mining groundwater conditions. Experience at other mines in similar geologic settings has found that groundwater levels tend to fluctuate being highest in the summer irrigation season and lowest in the winter and early spring. The monthly measurements will be tabulated and included with the DRMS annual report for the site. If, during mining or reclamation, the relative seasonal groundwater elevation at monitoring wells 5 or 6 show mounding of more than two (2) feet, and the condition was not observed during baseline monitoring, or if the miner or the Division receives any groundwater impact complaint, then the miner will evaluate the cause and take action within 7 days and notify the DRMS. After the DRMS has been notified, the miner will review the data and available information and submit a report to the DRMS within 30 days. The evaluation will include discussions with the well owner who has contacted the miner regarding a concern and review of baseline data from the well and vicinity to evaluate whether changes may be due to seasonal variations, climate, mining, slurry wall lining or other factors. The report will identify the extent of potential or actual impacts associated with the changes. If the extent of Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 4 groundwater changes due to mining or reclamation activities is determined to be a significant contributing factor that has or may create adverse impacts, the mining associated impacts will be addressed to the satisfaction of the DRMS. Miner will begin implementing one or more mitigation measures if mining and reclamation activity is determined to be a significant factor to groundwater changes requiring mitigation. Mitigation measures may include, but are not limited to: ➢ Placing water in a recharge pond to raise groundwater levels around the well. ➢ Constructing a local clay liner at the edge of the mine Cell (i.e. between the dewatering point and the well) in order to raise water levels on the well side of the liner and mitigate dewatering effects. ➢ Cleaning the well to improve efficiency. ➢ Providing an alternative source of water or purchasing additional water to support historic well use in terms of water quantity and quality. If needed, water quality parameters will be checked in affected wells to ensure alternative sources support historic use. ➢ Modifying a well to operate under lower groundwater conditions. This could include deepening the well or lowering pumps. All work would be done at the miner's expense with the exception of replacing equipment that was non-functional prior to mining. Groundwater Quality Monitoring Plan Since mining operations at the site will take place inside of slurry wall lined cells, except for establishing the Freshwater Pond and Siltation Pond, it is unlikely that these operations will have a negative effect on groundwater quality. To establish pre -mining groundwater quality for the site the permittee will sample MW -2 on the downgradient side of the site and MW -5 on the upgradient side of the site prior to mining. To establish that mining has had no negative affect on water quality in the area, The Operator will sample MW -2 annually during the same quarter as the initial baseline monitoring. The water quality samples will be tested for the analytes listed in Tables 1 through 4 of "The Basic Standards for Ground Water," excluding the radiological section of Table 1. RMCC will notify DRMS within 7 days of receiving a lab report that indicates any of the standards set forth in Tables 1 through 4 have been exceeded. If a lab report indicates an exceedance, a new sample will be taken to verify the exceedance and discount lab contamination. Any water quality lab results will be included in the DRMS annual report for the site. Annual groundwater testing will be conducted for the life of the mine unless the requirement has been reduced or eliminated through the Technical Revision process with the DRMS. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 5 CIVIL RES'SURCES,LLC ENGINEERS S. PLANNERS December 1st, 2022 Mr. Peter Hays Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 RECEIVED DEC 02 2022 WELD COMMISSIONERS RE: Red Tierra Equities, L.L.C., Section 20 Mine, File No. M-2022-001, 112c Permit Application Adequacy Review 6 Response Dear Mr. Hays: This letter addresses the Adequacy Review letter dated November 20th, 2022 regarding the Section 20 Gravel Mine 112 Construction Materials Reclamation Permit Application Package. Responses to your comments follow in bold: Exhibit C - Pre -Mining and Mining Plan Maps - Rule 6.4.3 1. In response to Item #1, the Applicant stated a recharge pond will be utilized to mitigate the groundwater shadow effect and to receive wafer from the underdrains and or dewatering wells. a. Please provide an Operations and Maintenance (O&M) plan for the recharge pond to prevent siltation of the pond. A Operations and Maintenance Plan has been included below the infiltration pond section included on Map C-5. b. Please provide a demonstration the recharge pond is sized appropriately to receive and dissipate the anticipated 6.5 CFS inflow at final build out of the mitigation system. The calculation sheet used to size the infiltration pond has been included. The method used is described in Massman, et al, 2003, "A Manual For Sizing Infiltration Ponds." c. Please provide a cross-section(s) of the recharge pond and update the Exhibit C-5 accordingly. Cross-section has been included on Exhibit C-5. Exhibit R - Proof of Filing with County Clerk and Recorder - 6.4.18 2. Please provide an affidavit or receipt indicating the date on which the revised application information required to address this adequacy letter was placed with the Weld County Clerk and Recorder for public review, pursuant to Subparagraph 1.6.2(1)(c). Groundwater Model. The copy of the email sent to Weld County has been included with this letter. 3. In response to Item #5, the Applicant stated the option to run the proposed pipeline from south to north along the midsection line to the infiltration pond located north of the site to keep the infrastructure on Section 20 is discussed in the Recharge Option in the Groundwater Model Report. The copy of the Groundwater Model report received by the Division on November 7, 2022 was the same report received on October 27, 2022 Please provide a revised copy of the groundwater model report incorporating the statements and commitments made by the Applicant in the adequacy review 5 response letter. The Groundwater Model Report has been updated to directly address the infiltration pond model run. The recommendations from the groundwater model have not changed. Red Tierra has committed to installing the infiltration pond by including it in the exhibits and it will be included in the bonding calculation. 8308 COLORADO BLVD • SUITE 200 • FIRESTONE, COLORADO 80504 • PHONE: 303.833.1416 • FAX: 303.833.2850 Pk, bl, C Re': w1,J .4, PI. (Tr/KWf * /0A) p.'(cH /ERIC K) 2022-2370 ,2.17/22 73-16122 Page 2 Mr. Peter Hays December 1, 2022 4. In response to Item #9, the Applicant stated if the miner receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the DRMS. Please commit to investigate al groundwater impact complaints received by the Operator or the Division. Please update the groundwater model report, Exhibit D - Mining Plan and Exhibit G - Water Information and any other applicable exhibits accordingly. Exhibit G — Water Information has been updated to "...or if the miner or the Division receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the DRMS." Exhibit G has been included in the appendices of the Groundwater Model Report and language has been added in the conclusions stating that the operator will comply with the Groundwater Level Monitoring and Mitigation plan. There is no section in Exhibit D — Mining Plan that references groundwater monitoring or well owner complaints, all of this information is contained in Exhibit G, specifically the Groundwater Level Monitoring and Mitigation Plan. 5. Please provide the groundwater model outputs (head contour maps similar to Figures 9 and 10) demonstrating the proposed mitigation measures utilizing the recharge pond will mitigate the expected groundwater impacts at final build out of the site. A head contour map for the infiltration pond model run has been included with the Groundwater Model Report as Figure 11. Please feel free to contact me with any questions or concerns at Kvleacivilresources.com or my cell number 408-930-2544. Regards, CIVIL RESOURCES, LLC Kyle Regan Project Geologist J..Illnited Water& San - 1411Section 201DRMSICorrespondencelDRMSIAdequacylGroundwaterModel Response_10102022.doc 50 EEGT-0N 15 155 1.151,LNE CELLE ea us ALELL59:1, IIoI C.593:1 r•R.u:a9.+ 01 MO 05 5e 00CELL591 E!AYF5115.0L .1580 190,T55 z5 n below Call nRruRlmRmR. LEGEND: IX.51NG W5 LINE PPDPpeEO ACCESS ROAp _ IXISTING GIRT RGnp 155, EEL, i1NG 9URIED EIEClRIGL TING OVERHEAD aECTRIG FIEER OPTIC WATERWAY M 51.111NO WEIL9 6E.115.. t 905 c5.511 AO ELECT.. PO VJ CIVIL RE919URCE5 5. ET RED TIE0.RN EQUITIES, LLC cu EIpl a au O. 110 1NL swiEz ,u W� ow w Rylal[unn.�aouc ow, MINE PLAN AND TIMELINE EXHIBIT C-5 EXHIBIT G - WATER INFORMATION This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.4.7 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Locate on the map (Exhibit C) tributary water courses, wells, springs, stock water ponds, reservoirs and ditches The site is 0.4 miles east of the South Platte River. Please refer to Exhibit C for locations of water courses in close proximity to the site, including wells, springs, stock water ponds, reservoirs and ditches. (b) Identify all known aquifers The site is underlain by a shallow alluvial aquifer, typical of its position upgradient of the South Platte River. (c) Show how water from dewatering operations or runoff from disturbed areas, piled material and operating surfaces will be managed to protect against pollution of either surface or groundwater both during and after the operation. Please refer to the Mining Plan Map in Exhibit C-5 of this application. Mine areas will drain internally. Uncontrolled releases of surface water in disturbed areas will not occur. Stormwater collected in the active mine area will be managed through the dewatering system. Dewatering will be accomplished by digging a sump, generally along the base of the mine slope, which will hold a floating pump. The pump will have an HDPE discharge line that will be routed to one of the comingled discharge points located at the site. The pump will be powered by a diesel generator housed in the active mine area. The Operator will apply for and receive a comingled stormwater and process water discharge permit prior to dewatering at the site. (d) Estimate project water requirements includingflow rates and annual volumes for the development, mining and reclamation phases of the project. Water needs estimated below provide for sustained production as detailed in the Mining Plan. The Operator will adjust water supplies to account for actual demand, avoid waste, and continuously comply with laws and regulations of the Division of Water Resources and any other water agency having jurisdiction over the operation. Projected Use And Consumption: Annual evaporative depletions will be the evaporation from up to 5000 feet of 4 -foot wide de -watering trench, located inside of the slurry wall. The total area of exposed water is 0.5 acres. The gross annual evaporation at the Section 20 Mine is 42 inches according to NOAA Technical Report NWS 33, Evaporation Atlas for the Contiguous 48 United States. Monthly evaporative losses are determined using percentages specified by the State Engineer's Office for locations below 6,300 feet. The nearest weather station is in Longmont where the average annual precipitation is 15.08. Effective Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G -1 precipitation, that part of historical precipitation which was consumed by native vegetation on land to be covered by water surface, is conservatively estimated to be 70 percent of the total precipitation. The annual average effective precipitation at the property is estimated to be 9.09 inches. When subtracting the effective precipitation from the gross evaporation yields, the net annual evaporation is 31.44 inches, or 2.68 acre-feet per acre. The Fresh Water Pond is approximately 10 acres and the Siltation Pond will be utilized in 10 acre stages. The approximate acreage of open water surface is 20.5 acres. The annual amount of evaporation from open water surfaces is 54.9 acre-feet. Mining Production & Operations: The Operator expects to extract approximately 2 million tons annually of aggregate material from the site. All water retained in the recovered material will be replaced pursuant to the Substitute Water Supply Plan (SWSP). The total annual amount of water retained in the gravel product from mining activities totals approximately 27.2 acre-feet. The SWSP is renewed annually and will reflect analysis of production and depletion anticipated in each year of operation. In addition, an estimated 4.0 acre-feet of water per year will be used for dust control based (approximately) on 5,900 gallons per day for 5 days a week for 10 months. Annually the total evaporative and operational losses from mining activities (open water surface evaporation, water retained in the aggregate product, dust suppression) totals 86.1 acre-feet of depletion which must be augmented. All depletions were lagged to the Saint Vrain River using the lagging factors approved by the State Engineer pursuant to on -going Substitute Water Supply (SWSP) approvals. (e) Indicate the projected amounts of the water sources to supply project water requirements Replacement Water: The Miner will obtain an approved Substitute Water Supply Plan from the State Engineers office every year, providing annually or more frequently the opportunity to review the sufficiency of water supplies. The SWSP approvals require that the applicant provide a detailed explanation of the mining operations, a quantification of all mining activities and subsequent depletions and all legally available replacement sources. (f) Affirmatively state that the Applicant has acquired or applied fora National Pollutant Discharge Elimination System permit from the Water Quality Control Division The Operator will apply for a National Pollutant Discharge Elimination System (NPDES) permit from the Water Quality Control Division of the Colorado Department of Public Health and Environment prior to discharging water from the site. Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 2 Groundwater Sampling and Analysis Plan This information provided in this subsection of Exhibit G is intended to satisfy the requirements outlined in the Groundwater Monitoring and Protection Technical Bulletin dated November 19, 2019: Existing Groundwater Conditions The near surface groundwater is part of an alluvial aquifer in which permeable sand and gravel alluvium overlies relatively impermeable bedrock of either the Fox Hills Sandstone and/or the Laramie Formation. Groundwater, measured in 7 piezometers, occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the site. The prevailing groundwater flow at the site is to the north reflecting the site topography. Groundwater in the area is tributary to the South Platte River located northwest of the site. Locally the groundwater levels and flow directions are likely influenced by: ➢ The South Platte River is northwest of the site. For most of the year, the river likely acts as a drainage way maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the site under the intersection of Weld County Road 42 and Weld County Road 29. The ditch may act like a drain during the non - irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ The Farmers Independent Ditch traverses the southeast corner of the site and bisects Cell 5a and 5b. The ditch may act like a drain during the non -irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ Irrigation: The site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration likely recharges the groundwater. ➢ Alluvial wells: Other than the seven monitoring wells drilled at the site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the site, two wells east of the site, nine wells south of the site and one well west of the site. If pumping, groundwater will be drawn to these wells. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 3 Potential Slurry Wall and Mining Impacts to Local Groundwater Levels For all lined cells, a properly constructed slurry wall will tend to isolate these cells from the surrounding alluvial groundwater table. The liner around these cells could cause "mounding" of groundwater (increase in groundwater elevation) on the upgradient side (southeast) of the lined cells and a potential "shadow effect" (reduction in groundwater level) on the downgradient side (northwest) of the mine. Because the liner will tend to isolate these cells from the surrounding groundwater table, the effects of dewatering when mining lined cells will tend to not extend beyond the liner. Any mounding effect on the upgradient side of the site (south and southwest) is anticipated to be on the order of a few feet or less and will dissipate with distance from the mine. Similarly, shadowing effects will be on the order of a few feet and will dissipate with distance from the mine. The shadowing effects will be minimized by the presence of the South Platte River to the northwest and the Western Mutual Ditch that runs between Cells 5A and 58 and the Farmers Independent Ditch which runs southeast of the site. Dewatering of the unlined cells (Cells 1 and 2) will result in decreases in water levels around these cells. Since there are no wells permitted within 600' of the unlined cells, the effects of dewatering the unlined cells will be minimal. Area Wells A review of the permitted wells on file with the State Engineer's Office (SEO), Division of Water Resources (DWR) indicates that there are nineteen permitted pumping wells within 600 feet of the permit boundary. All of these wells are screened in the alluvium. None of these wells are within 600 feet of the unlined cells (Cells 1 and 2). The well locations and applicants are shown on Figure G-2 attached at the end of this section. Groundwater Level Monitoring and Mitigation Plan Dewatering during mining of Cells 1 and 2 is unlikely to affect any wells in the area. However, if the miner receives a complaint, the following mitigation plan will be implemented. The site monitoring wells will be measured monthly to identify potential changes in alluvial groundwater flow or elevation associated with mining and reclamation activities. Baseline data will be collected prior to dewatering or construction of the slurry walls. Baseline data will be collected from the monitoring program will provide a range of relative water levels associated with pre -mining groundwater conditions. Experience at other mines in similar geologic settings has found that groundwater levels tend to fluctuate being highest in the summer irrigation season and lowest in the winter and early spring. The monthly measurements will be tabulated and included with the DRMS annual report for the site. If, during mining or reclamation, the relative seasonal groundwater elevation at monitoring wells 5 or 6 show mounding of more than two (2) feet, and the condition was'not observed during baseline monitoring, or if the miner or the Division receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the DRMS. After the DRMS has been notified, the miner will review the data and available information and submit a report to the DRMS within 30 days. The evaluation will include discussions with the well owner who has contacted the miner regarding a concern and review of baseline data from the well and vicinity to evaluate whether changes may be due to seasonal variations, climate, mining, slurry wall lining or other factors. The report will identify the extent of potential or actual impacts associated with the changes. If the extent of Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 4 groundwater changes due to mining or reclamation activities is determined to be a significant contributing factor that has or may create adverse impacts, the mining associated impacts will be addressed to the satisfaction of the DRMS. Miner will begin implementing one or more mitigation measures if mining and reclamation activity is determined to be a significant factor to groundwater changes requiring mitigation. Mitigation measures may include, but are not limited to: ➢ Placing water in a recharge pond to raise groundwater levels around the well. ➢ Constructing a local clay liner at the edge of the mine Cell (i.e. between the dewatering point and the well) in order to raise water levels on the well side of the liner and mitigate dewatering effects. ➢ Cleaning the well to improve efficiency. > Providing an alternative source of water or purchasing additional water to support historic well use in terms of water quantity and quality. If needed, water quality parameters will be checked in affected wells to ensure alternative sources support historic use. > Modifying a well to operate under lower groundwater conditions. This could include deepening the well or lowering pumps. All work would be done at the miner's expense with the exception of replacing equipment that was non-functional prior to mining. Groundwater Quality Monitoring Plan Since mining operations at the site will take place inside of slurry wall lined cells, except for establishing the Freshwater Pond and Siltation Pond, it is unlikely that these operations will have a negative effect on groundwater quality. To establish pre -mining groundwater quality for the site the permittee will sample MW -2 on the downgradient side of the site and MW -5 on the upgradient side of the site prior to mining. To establish that mining has had no negative affect on water quality in the area, The Operator will sample MW -2 annually during the same quarter as the initial baseline monitoring. The water quality samples will be tested for the analytes listed in Tables 1 through 4 of "The Basic Standards for Ground Water," excluding the radiological section of Table 1. RMCC will notify DRMS within 7 days of receiving a lab report that indicates any of the standards set forth in Tables 1 through 4 have been exceeded. If a lab report indicates an exceedance, a new sample will be taken to verify the exceedance and discount lab contamination. Any water quality lab results will be included in the DRMS annual report for the site. Annual groundwater testing will be conducted for the life of the mine unless the requirement has been reduced or eliminated through the Technical Revision process with the DRMS. Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 5 CIVIL RES'VURCES, LLC ENGINEERS & PLANNERS MEMORANDUM TO: Robert Lembke Red Tierra Project File — Section 20 Gravel Mine FROM: Civil Resources, LLC DATE: October 14, 2022 RE: Modifications to Model in Response to DRMS Comments This memorandum summarizes the modifications to the Section 20 Groundwater Model Report dated August 2022 in response to a Division of Reclamation Mining and Safety (DRMS) comment that the Monarch DENM Gravel Mine, west of the site, be included in the Section 20 groundwater model (Adequacy Review dated September 12, 2022). Model modifications include: ➢ Added the Monarch DENM Gravel Mine slurry walls to the mitigation scenarios. ➢ An underdrain was included on the Monarch DENM Site. ➢ Due to the additional obstruction, the eastern mitigation system of an underdrain or dewatering wells pumping 2.5-3.25 cfs was modeled to be constructed at the same time as the Cell 4 slurry wall rather than during the construction of the Cell 5N slurry wall. ➢ Approximately 1,900 feet of underdrain was modeled to be constructed at the same time as the Cell 6 slurry wall to run between the Cell 6 slurry wall and Weld County Road 42. This drain was sized to remove 3.3 cfs from the model via discharge to the river which will require coordination with the Monarch DENM ownership group. The recommendations presented in the August 2022 report mitigated the groundwater mounding modeled to occur with full build -out of Section 20 slurry walls and the related rise in groundwater in the area of the Town of Gilcrest east of the Section 20 Site. The addition of the Monarch DENM resulted in further obstruction of groundwater flow around the west side of Section 20 resulting in additional regional mounding that requires a second underdrain system that conveys the flow to the river and limits the upstream groundwater rise via a westward draining underdrain beginning near the southwest corner of the Section 20 Site and carrying approximately 3.3 cfs to the South Platte River (approximately 1,900 feet long). Attachments: - DRMS Response Letter - Revised Groundwater Model Report J:IUnited Water & San-1411Section 201oRMSIGroundwaterlMEMO_Groundwater Model Modifications.docx 8308 C❑L❑RAD❑ BLVD, SUITE 200 • FIREST❑NE, C❑L❑RAD❑ 80504 • PH❑NE: 303.833.1416 CIVIL RES'URCES,LLC ENGINEERS & PLANNERS October 14, 2022 Mr. Peter Hays Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 RE: Red Tierra Equities, L.L.C., Section 20 Mine, File No. M-2022-001, 112c Permit Application Groundwater Model Review; Response Dear Mr. Hays: This letter addresses the Adequacy Review letter dated September 12, 2022 regarding the Section 20 Gravel Mine 112 Construction Materials Reclamation Permit Application Package. Responses to your comments follow: 1. On the acknowledgement page the signature and seal are missing, please provide the missing information. Signature and Seal have been included. 2. The area is modelled as one slurry wall but there are going to be up to 8 individual walled cells. The Division is concerned that during construction of the individual cells, not just cell 5S, there could be mounding and shadowing effects that are overlooked or obscured by modelling the site as one cell, please comment. The site was modelled as individual cells from Ce113 to Cell 6 to determine the phasing of the mitigation measures proposed in the August 2022 report. The tables and figures 8 through 10 from the individual model runs have been included in the modified Report. The Mining Plan report discusses the mounding resulting from the slurry walls being interconnected resulting in full obstruction of groundwater flow which represents the "worst case scenario" for mounding and shadowing effects. 3. The Division is aware there is an approved slurry wal structure that will be located immediately to the west of this site, Monarch Mountain (M2022-009). The installation of this structure needs to be included into the model and the model re -run to determine how groundwater is affected by both slurry walled structures. The inclusion of the Monarch DENM site in the model simulations results in CR recommending additional mitigation measures to include: 1) dewatering wells or an underdrain in the southeastern corner; and 2) an underdrain starting west of the Western Mutual Ditch and CR 44 intersection extending west finally daylighting into the South Platte River valley. The dewatering infrastructure (wells/underdrain) in the southeast will be designed to remove a minimum of 3.25 cfs and the underdrain to the west will remove at least 3.26 cfs. An underdrain is also needed on the Monarch DENM Site between Cell 3 and WCR 42 to offset this mine's contribution to the regional groundwater level impacts and this same alignment would be easily combined with the Section 20 discharge in a single outfall (Refer Figure 6). 4. The report states the shadowing effects to the north will be minimized by the unnamed slough and infiltration ponds. Please provide modelling that demonstrates this will be the case. Additionally, if the infiltration ponds were to go dry as a result of the shadowing the Applicant needs to provide a mitigation plan. Included in the mitigation plan for shadowing the Applicant needs to propose groundwater levels that will begin the mitigation efforts. Mitigation measures proposed to address the potentially negative impacts of constructing the subject slurry wall(s) include: 8308 COLORADO BLVD • SUITE 200 • FIRESTONE, COLORADO 80504 • PHONE: 303.533.1416 • FAX: 303.833.2850 Page 2 Mr. Peter Hays October 14, 2022 - Mounding (upgradient; south): Mitigation measures addressing the modeled mounding have been thoroughly discussed and described and include gravity underdrains and dewatering wells that can be activated in response to elevated groundwater conditions. Shadow (downgradient; north): The lower groundwater elevations modeled downgradient (north) of the slurry wall are do not pose a significant impact to the area alluvial wells because the saturated thickness of the alluvium is still eighteen (18) feet. However, a recharge area will be preserved on the Site to allow the upgradient dewatering discharge to be used to raise the groundwater level locally adjacent to the agricultural production wells. Refer Figure 7. The unnamed slough is modeled as a drain with a very large conductance which sets the upper elevation of the groundwater table and therefore it serves to limit the potential drawdown in the "shadow" area. The model results have been included with the email version of this letter (model output SW TOT SP). 5. Please provide the details (length, diameter and timing of installation) of the underdrain proposed to mitigate the mounding effects to the south of the site. Additionally, provide the modelling results that demonstrate the proposed underdrain will mitigate the mounding. The model outputs have been included in the email copy of this letter. 6. Please provide the details (diameter, depth and timing of installation) of the dewatering wells proposed to mitigate the mounding effects to the south of the site. Additionally, provide the modelling results that demonstrate the dewatering wells will mitigate the mounding. Dewatering wells or the eastern underdrain will be installed during construction of Cell 4. The finally designed system will remove a minimum of 3.25 cfs at full buildout and will require a 12" pressurized discharge line or 24" gravity underdrain. The model results demonstrating dewatering wells will mitigate mounding have been included with the email version of this letter. The west underdrain will be a 24" slotted pipe with the invert set at 4,735 in the east (west side of Western Ditch along CR 44) and 4,733 in the west. The elevations are subject to change as more data on seasonal water levels are collected. The west underdrain will be installed during construction or prior to construction of Cell 6. 7. What will determine what southern mitigation scenario will be used; underdrain, dewatering wells or a combination of both? The final design of the mitigation measures will be determined with input from the Town of Gilcrest and the local permitting process. 8. The Figures 7 and7A referenced in the report were not provided. Are they the same as Figures 6 and 6A that were provided? Please update the text as needed or provide the missing figures. Report has been updated. 9. Please provide the details of the drain recharge manhole and associated piping to be installed to mitigate the shadowing to the north of the site, also referred to as Option1. Additionally, the paragraph before Table 7 states that water will routed to the river for Option 1. Please clarify if the water will be routed to the drain recharge or to the river. Report has been updated. 10. Option 2 of the three mitigation options states water will be routed via the surface to discharge to the river. Please show the route the piping will take to get to the river and where the discharge point will be located. The possible routes have been shown on the attached mitigation maps. Page 3 Mr. Peter Hays October 14, 2022 Please feel free to contact me with any questions or concerns at Kvle(a.civilresources.com or my cell number 408-930-2544. Regards, CIVIL RESOURCES, LLC Kyle Regan Project Geologist J.9United Water& San-1411Section 201DRMSICorrespondencelDRMSIAdequacylGroundwaterModel Response_10102022.doc GILCREST AREA ALLUVIAL GROUNDWATER MODEL POTENTIAL IMPACTS OF PROPOSED GRAVEL MINING PREPARED FOR: Red Tierra Equities, LLC. 8301 Prentice Avenue Suite 100 Greenwood Village, CO 80111 PREPARED BY: Civil Resources, LLC 8308 Colorado Blvd Suite 200 Firestone, CO 80504 303.833.1416 DATE PREPARED: AUGUST, 2022 REVISED: DECEMBER, 2022 GILCREST AREA ALLUVIAL GROUNDWATER MODEL ACKNOWLEDGMENTS The technical material in this report was prepared by Civil Resources, LLC under the supervision and direction of the undersigned whose seal as a professional engineer is affixed below: ORE S Brad Hagen, P.E. ,,///1111111:10 ��1 The following members of Civil Resources, LLC staff contributed to the study and the preparation of this report: Project Manager: Project Geologist Brad Hagen, P.E. Kyle Regan, P.G. TABLE OF CONTENTS Paae 1.0 INTRODUCTION 1 2.0 AREA GEOLOGY 1 3.0 SITE GEOLOGY 1 4.0 EXISTING GROUNDWATER CONDITIONS 2 5.0 GROUNDWATER MODEL 3 5.1 Regional Topography 3 5.2 Bedrock Surface 3 5.3 Hydraulic Conductivity 4 5.4 Specific Yield 4 5.5 Boundary Conditions 4 5.6 Internal Influences 5 6.0 MODEL SIMULATIONS 6 6.1 Existing Conditions 6 6.2 Slurry Wall Installation 7 6.2.1 Monarch Mountain Minerals and Aggregates Site Impacts 8 6.3 Mitigation Alternatives 9 6.3.1 Phase 1 Mitigation 10 6.3.2 Phase 2 Mitigation 11 6.3.3 Mitigation With Recharge 12 7.0 CONCLUSIONS 13 8.0 BIBLIOGRAPHY 13 Tables Table 1 Boundary Conditions 5 Table 2 Measured and Modeled Site Groundwater Levels 7 Table 3 Mining Groundwater Level Table (Slurry Walls In -Place) 8 Table 3aMining Groundwater Level Table with Monarch DENM Site 9 Table 4 Base Model and Modeled Site Groundwater Level After Cell 3 Slurry Wall 10 Table 5 Base Model and Modeled Site Groundwater Level After Cell 3, and 4 Slurry Walls 11 Table 6 Base Model and Modeled Site Groundwater Level After Full Buildout at Both Sites 12 Groundwater Model Report — Section 20 Gravel Mine Site - ii - August 2022 Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 4A Figure 5 Figure 5A Figure 6 Figure 6A Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Appendices Regional Bedrock Contours Base Model Conditions Horizontal Hydraulic Conductivity Existing Condition Contours Existing Condition Contours(zoomed to site area) Slurry Wall Full Build Out Condition Contours Slurry Wall Full Build Out Condition Contours(zoomed to site area) Slurry Wall with Drain Condition Contours Slurry Wall with Drain Condition Contours (zoomed to site area) Slurry Wall With Drain and Recharge (zoomed to site area) and Details Cell 3 Slurry Wall Condition Contours Cell 3, 4 and Monarch DENM Cell 1 Slurry Wall Condition Contours Cell 3, 4, 5N and Monarch DENM Cell 1 Slurry Wall Condition Contours Full Buildout with Infiltration Pond Condition Contours Appendix A Monthly Water Readings and Diversion Graphs Appendix B Excerpts from Bishop-Brogden Associates, "Dewatering Improvements Study" 2016 Appendix C Excerpts from Principia, "Gilcrest Groundwater Flow Model" 2019 Appendix D Excerpts from Colorado State University, 'Study of the South Platte River Alluvial Aquifer" 2013 Appendix E Groundwater Level Monitoring and Mitigation Plan Groundwater Model Report - Section 20 Gravel Mine Site - ii - August 2022 Groundwater Model Report — Section 20 Gravel Mine Site - ii - August 2022 1.0 INTRODUCTION The Section 20 Gravel Mine (Site) is located on Colorado State Highway 60 to the west, Weld County Road 44 to the north, Weld County Road 29 to the east and Weld County Road 42 to the south. More specifically, the Site is comprised of the majority of Section 20, Township 4 North, Range 66 West of the 6. Principal Meridian. The Site is planned to be a construction aggregate material mine to accommodate growth in the area. The current mine plan calls for eight (8) soil bentonite slurry walled cells that will encompass most of the Site excluding approximately 20 acres in the northwest corner of the Site which will wet mined and backfilled with wash fines and waste material. Currently, overburden is being mined in the future Cell 8 under an approved Division of Reclamation Mining and Safety (DRMS) 111 Special Operations Permit. No groundwater is planned to be exposed during this operation. A groundwater model was prepared for Red Tierra Equities, LLC's Section 20 Gravel Mine Site (Site) to investigate the impacts of the final construction of slurry walls at the Site on the surrounding alluvial aquifer. This report details the model inputs and construction, the findings of the model and recommendations to mitigate alluvial aquifer impacts. 2.0 AREA GEOLOGY The Site is located approximately 25 miles east of the eastern flank of the Rocky Mountain Front Range. Younger sedimentary strata dip eastward off the Pre -Cambrian igneous and metamorphic rocks that form the core of the Front Range into the Denver Structural Basin. The Denver Basin is an asymmetrical downwarp of sedimentary strata with a steeply dipping west limb and a gently dipping east limb. Bedrock does not crop out at the Site, however regional geologic mapping of the area (Colton, 1978) indicates the near surface bedrock at the Site is most likely the Laramie Formation. Colton (1978) describes the Laramie Formation as mostly claystone, shale, sandy shale, and lenticular sandstone (refer Figure 1). The regional mapping indicates the bedrock is overlain by the Broadway Alluvium. Colton (1978) describes these alluvial deposits as sand and gravel deposited by the South Platte River and its tributaries. In addition to the sonic borings drilled by Cascade, Civil Resources analyzed and mapped bedrock from 177 well logs from the Division of Water Resources. As shown on Figure 2, bedrock in the area generally slopes to the northeast following the route of the South Platte River. Approximately one and a half (1.5) miles southeast of the South Platte River the bedrock drops in elevation dramatically from an elevation of 4696 feet in the northwest corner of Section 20 to an elevation of 4664 feet around the Town of Gilcrest. On the southeastem side of Highway 85 the bedrock rises to an elevation of 4719 feet on the southeast side of Highway 85. 3.0 SITE GEOLOGY A total of 23 borings were drilled to bedrock at the Section 20 Site. Depth to bedrock ranged from 39.5 feet in BH-38 in the northeast corner of the Site to 97.5 feet in BH-41 in the southeast corner of the Site. The bedrock encountered at the Site consisted of wet brown weathered claystone in the first 6 inches to 1 foot which transitioned into moist to dry, olive to grey claystone with further depth. The claystone had a high plasticity and minimal fracturing. The bedrock unit was not sampled. Depth to bedrock is mapped out in Figure 1. The alluvial aquifer at the Site consist mainly of gravelly sand which grades to sandy gravel, usually becoming more gravelly with depth. Some cobble units (grain size 4" or greater) were encountered at the Site; mainly consisting of a few feet overlaying bedrock. Aggregate unit thickness varied from 35 feet in BH-36 in the northern side of the Site to 72.5 feet in BH-27 in the eastern side of the Site. Groundwater Model Report— Section 20 Gravel Mine Site -1 - August 2022 4.0 EXISTING GROUNDWATER CONDITIONS Groundwater was measured in seven (7) piezometers, and typically occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the Site. The prevailing groundwater flow direction at the Site is to the north reflecting the Site topography. Groundwater in the area is tributary to the South Platte River located northwest of the Site. Depth to groundwater is shallower, as little as 5 feet, underlying the Town of Gilcrest likely due to the deep bedrock and low topography relative to the surrounding area. Locally the groundwater levels and flow directions are influenced by: ➢ The South Platte River is northwest of the Site. For most of the year, the river likely acts as a drainage way, or gaining river reach, maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the Site under the intersection of Weld County Road 42 and Weld County Road 29. North of Weld County Road 36, the ditch joins with a wetland drain which likely provides water year-round. During the irrigation season, the ditch diverts water from the South Platte River as well raising the water level of the ditch. ➢ The Farmers Independent Ditch traverses the southeast corner of the Site and bisects Cell 5a and 5b. The ditch flows most of the year based on diversion records for the ditch headgate located southwest of Platteville. > The Evans #2 Ditch passes southeast of the Town of Gilcrest on the eastem side of Highway 85. The ditch did not have discharge during the months of November and December but did have flow during the remainder of the year. > The Platte Valley Ditch branches off from the Evans #2 Ditch south of the Town of Gilcrest. The Platte Valley Ditch does not have a stream gage, so it was assumed that it was flowing at the same time as the Evans #2 Ditch. ➢ There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the Site during the irrigation season. > There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the Site during the irrigation season. > There are two unnamed sloughs approximately'/Z a mile to the west and another a'A mile to the north of the Site respectively. These sloughs receive groundwater flowing out from the higher terrace and act as drains moving water to the river. > There are multiple recharge ponds it the area of interest which provide groundwater recharge (refer Figure 2). ➢ Irrigation: The Site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration recharges the groundwater. Groundwater Model Report — Section 20 Gravel Mine Site - 2 - August 2022 ➢ Alluvial wells: Other than the seven monitoring wells drilled at the Site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the Site, two wells east of the Site, nine wells south of the Site and one well west of the Site. If pumping, groundwater will be drawn to these wells. 5.0 GROUNDWATER MODEL The MODFLOW program utilizes a finite -difference mathematical model to simulate groundwater flow developed by the United States Geological Survey (USGS). Groundwater Modeling System (GMS V 10.4.10) provided the graphical user interface for entering and reviewing the MODLFOW data. The model has a total area of approximately 42 square miles, extending from the South Platte River to the west, the Town of Platteville to the south, the Evans #2 Ditch to the east and the Town of La Salle to the north (refer to Figure 1). The grid size is 200 feet by 200 feet squares. The following boundary conditions were applied to the model as presented in Figure 2: ➢ South Platte River to the northwest (River Package within MODFLOW); ➢ A constant head boundary to the south; ➢ A no flow boundary to the east to simulate the rise in bedrock east of Highway 85; ➢ A constant head boundary to the north; ➢ Claystone bedrock — acting as an aquitard forming the bottom of the aquifer. The shallow alluvial aquifer was modeled as a single aquifer (sand and small gravel), with zoned hydraulic conductivities based on historical well pumping tests, underlain by impervious claystone bedrock. The model parameters and boundary conditions, such as Site topography, bedrock elevations, and hydraulic conductivities are further discussed in the following sections. 5.1 Regional Topography Surface topography was obtained from USGS digital quadrangle (the Milliken 7.5 minute quadrangle). The digital map was converted into a Civil 3d surface and imported to GMS and interpolated to the top elevations of the aquifer layer. 5.2 Bedrock Surface The bedrock surface for the Site was obtained from borings completed by Civil Resources at the Site as well as 177 wells logs retrieved from the Colorado Division of Water Resources webSite. These points were entered into Civil 3d to create a surface and smoothed using natural neighbor interpolation with a 20 -foot by 20 -foot interval. Bedrock is exposed to the west of the South Platte River, indicating that the alluvial aquifer pinches out to the west. A feature line was used to map out the bedrock outcrop to bring the bedrock surface to meet the ground surface west of the river. Corrections were made to this surface to lower the bedrock in areas in order to maintain usable cells along the river corridor and bedrock is likely shallower than the model input in this region. 5.3 Hydraulic Conductivity Hydraulic conductivity is a measure of the soils ability to transmit water within the aquifer. Some factors affecting hydraulic conductivity are: pore size distribution, grain size distribution, void ratio, roughness of mineral particles, and Groundwater Model Report — Section 20 Gravel Mine Site - 3 - August 2022 degree of soil saturation (Das, 1998). The alluvium, underlying the region, is generally a clean to silty sand and gravel, as described above with an approximate depth of 50 to 95 feet in the upper terrace and shallower than 10 feet along the South Platte River floodplain. Aquifer properties used in a previous study of the area performed by Bishop-Brogden Associates, Inc.(BBA) for the Town of Gilcrest were incorporated as this report utilized two long-term aquifer pumping tests in the vicinity of Gilcrest: the B4-66-11adc well 3 miles north of Gilcrest and the Lorenz Well approximately'% mile to the east of Gilcrest. ➢ The B4-66-011 adc well approximately 3 miles north of Gilcrest is the nearest controlled long-term aquifer pumping and showed a hydraulic conductivity of 1,270 ft/day. ➢ BBA performed an analysis of water level data from observation wells located near the Lorenz Well approximately 1/2 mile to the east of Gilcrest. Their analysis indicated a hydraulic conductivity of approximately 150 ft/day. The hydraulic conductivity was set at the lower end of the ranges provided by BBA and were increased until the model heads converged. The model is sensitive to horizontal hydraulic conductivity and operates without errors in a narrow range of values at the high end of the ranges provided by BBA. Horizontal hydraulic conductivity for the calibrated model range from a low of 65 ft/day for the hills to the east and a high of 805 ft/day underlying the Site. An area of high horizontal hydraulic conductivity. A map with the horizontal hydraulic conductivity values utilized in the model is shown on Figure 3. 5.4 Specific Yield Specific yield for the aquifer was set at 20% which corresponds to the value determined by BBA and in support of numerous water court decrees. 5.5 Boundary Conditions Boundary conditions were set based on geologic features on the east and west sides of the model. The constant head boundaries on the south and north sides were varied to match observed groundwater data sets. > Boundary conditions in a groundwater model are one tool used to approximate existing conditions at the outer extent of the model. The boundary conditions are set sufficiently far away from the area of interest to allow the aquifer to respond to local stresses and are based on hydraulic, hydrogeologic, hydrologic, geological and geographical assumptions. ➢ The model extends 3.3 miles southwest where constant head nodes were placed approximately 14 feet below the ground surface to represent existing groundwater levels taken in the area. ➢ Another constant head boundary was place approximately 3.7 miles northeast Site and constant head nodes were placed on the southeastern flank at water surface elevations approximately ten feet below the ground. > To the southeast of the model surface topography and bedrock slope up in elevation creating a natural barrier to flow. The eastern limit of the alluvial aquifer was confirmed by researching the states database of permitted wells in the area and mapping where the permitted aquifer switches from the alluvial aquifer to a deep confined aquifer. The approximate location of the shallow and deep aquifer divide is approximately'A mile east the location of the Platte Valley Ditch. ➢ The South Platte River forms a natural hydrologic boundary to the west of the model. Model inputs for the MODFLOW river package are bottom elevation, head -stage and conductivity. The bed elevation was estimated using the USGS topographic quadrangle and Google Earth top of bed elevation and subtracting 6 feet to Groundwater Model Report — Section 20 Gravel Mine Site - 4 - August 2022 account for riverbed depth. Head -stage was taken from the South Platte River at Platteville, CO (PLAPLACO) monitoring station which was approximately 4' during the period of interest. See Appendix A for the PLAPLACO station discharge graph. > River conductance is a model parameter in the river package which simulates the riverbed's ability to transfer water to the neighboring cell. The river conductance parameter is calculated by taking vertical hydraulic conductivity divided by bed thickness multiplied by river width. This value is then multiplied by GMS for the length of the river arc to which it is applied. Since the riverbed hydraulic conductivity is unknown for this reach of the South Platte River, it was necessary to calibrate this parameter to groundwater conditions at the Site. An initial conductance of 36 ft/day was determined from well test reports that occurred upstream of the Site north of Fort Lupton. Since the South Platte River acts as a drain throughout the reach, conductance values less than 150 ft/day caused unrealistic head values and flooded cells. Values higher than 160 ft/day cause head values to drop and dry cells through the area. The river conductance was modeled to increase from 150 ft/day where the river enters the model to 160 ft/day where the river exits the model. The rise in conductance was implemented to account for an increase in river width after the addition of the Saint Vrain River and groundwater inflows. A summary of the boundary conditions is presented in Table 6 below. Table 1 Boundary Conditions Area Boundary Notes North Model extends 3.7 miles to the northeast See Figure 1 West South Platte River located approximately 4,000 feet west of Site River bounds the western side of the model, see Figure 1 South Model extends 3.3 miles to the southwest Constant head nodes, see Figure 1 East Steeper Slopes to a ridge, wells change from shallow to deep See Figure 1 The model boundary conditions are shown on Figure 2 5.6 Internal Influences Surface features and activities that affect the alluvial groundwater include: ➢ Ditches — There are four (4) ditches that traverse the interior of the model. These ditches were modeled in GMS as river nodes. As discussed in the South Platte River boundary condition above, the model inputs for the MODFLOW river package are: bottom elevation, head -stage, and conductance. The bed thickness for the ditches were all assumed to be 2 feet thick and to have a relatively low vertical hydraulic conductivity to limit seepage and were used as a calibration tool to match local groundwater elevations. Head stage was estimated from the FRMDITCO, WESDITCO, EVANS2CO river diversion monitoring stations(See Appendix A). The HB12-1278 Study of the South Platte River Alluvial Aquifer, performed by Colorado State University, states that calculated ditch seepage in the ranges from 10 to 50 percent, averaging at 23 percent. In the area of interest, ditch width ranges from approximately 10 feet wide to 30 feet wide. Assuming the 2 -foot bed thickness and starting with 10 percent seepage, ditch conductance was set at 0.5 ft/day and was raised incrementally until known groundwater head elevations and gradient were Groundwater Model Report— Section 20 Gravel Mine Site - 5 - August 2022 reached. It was assumed that seepage from the ditches reduced over distance as water was consumed. See Figure 1 for inputted parameters. The Western Mutual Ditch was the main factor in determining head values at the Section 20 Site and small changes in head elevation and conductance were used to calibrate the river input to reach observed head measurements throughout the Site. > Drains — A series of drains were set at the base of three sloughs along the South Platte River. These drains were necessary to pull head elevations down to the slough elevation and not flood out the cells in the floodway. The drain inputs are bottom elevation and conductance. The bottom elevation was estimated from the USGS Quadrangle Map and were assumed to be at least 2 feet deep. The conductance input was set high enough to account for all water that was above the drain bottom to model the slough action of removing groundwater and setting groundwater head levels at the base of the terrace. ➢ Recharge — A number of upgradient recharge Sites were listed in the BBA report and were added to this model. The recharge values and location are located on Figure 2. It was assumed that pivot and flood irrigation contributed 0.001 feet per day to the groundwater table over the whole model area during irrigation season. 6.0 MODEL SIMULATIONS 6.1 Existing Conditions Steady-state modeling of average baseline conditions of April through July were used to calibrate the system equilibrium to the measured water levels. Monthly water level readings and other reported data can be seen in Appendix A. The aquifer was modeled as consisting of alluvium from the existing ground surface to the top of bedrock. Civil Resources evaluated the claystone bedrock as an aquiclude, thereby forming the bottom of the model. The observed water levels used to calibrate the steady-state model are shown on Figure 1. Calibration is the process of refining input parameters and boundary conditions, within reason, so the model reflects observed water levels. Parameters including: 1) hydraulic conductivity, 2) river conductance, 3) river head, 4) aver bottom elevations, and 5) drain conductance were adjusted during calibration. The groundwater levels to the northeast were estimated from the level of the Lower Latham Reservoir. Groundwater levels to the southwest were estimated from monitoring wells in the area. The South Platte River, ditches and drain bottom elevations were estimated utilizing the USGS Quadrangle map and water surface elevations were estimated using stream gage head information from the DWR website(See Appendix A). Figure 5 shows the modeled groundwater contours and Figure 5A shows the modeled groundwater contours zoomed in on the Site and the Town. Table 2 below reports the steady-state modeled water levels and the measured water levels at the Site. Overall, the model matched the existing groundwater gradient to a good degree of accuracy and 6 out of the 7 Site monitoring wells were within 0.5 feet of observed. MW -1 was 2' above the observed head elevation. > MW -1 was drilled approximately 50 feet from a residence at the property and a search of well permits on the DWR Site shows that there are multiple wells, 3 owned by Red Tierra Equities LLC., are located within a 400 foot radius of the monitoring well. There is also a domestic well approximately 500 from MW -1 across Highway 60. These wells may locally influence the groundwater resulting in lower water levels observed in MW -1 than modeled, especially given that the gradient matches across the rest of the Site. Groundwater Model Report — Section 20 Gravel Mine Site - 6 - August 2022 Groundwater levels for monitoring wells in the Town of Gilcrest were also utilized in calibration of the model. The BBA report contained well readings from multiple wells in the Town of Gilcrest measured in 2014. It was assumed that these readings were similar to current head elevations and four (4) monitoring wells were included to get a representative sample of the Town. Of the four(4) wells chosen, three (3) of them were within 0.5 feet of observed. BBA-EC, northeast of town on the eastern side of Highway 85 was 1.5 feet lower than the observed elevation head. The monitoring wells included in the BBA report were recorded in 1 foot intervals, which could account for the 1.5 feet difference. Table 2 below has the comparison between the measured and modeled groundwater levels at the Site. The head contours for the baseline condition are shown on Figure 4. Table 2 Measured and Modeled Site Groundwater Levels Well Observed Modeled Difference Cell (IX) MW -1 4,725.40 4727.1 1.70 146,111,1 MW -2 4,718.17 4717.9 -0.27 136,119,1 MW -3 4,725.07 4724.9 -0.17 142,136,1 MW -4 4,732.07 4732.5 0.43 153,136,1 MW -5 4,736.43 4736.7 0.27 162,133,1 MW -6 4,738.43 4737.7 -0.73 162,115,1 MW -7 4,728.92 4728.9 -0.02 148,122,1 BBA-MW4 4741 4740.3 -0.70 148,122,1 BBA-MW11 4737 4736.9 -0.10 148,122,1 BBA-MW17 4735 4734.4 -0.60 166,164,1 BBA-MW18 4738 4737.25 -0.75 148,122,1 DROU-MW-01 4741.5 4743.4 1.90 177,86,1 DROU-MW-02 4743 4744 1.00 176,94,1 DROU-MW-03 4747.1 4747.3 0.20 182,93,1 DROU-MW-04 4749.1 4750 0.90 187,93,1 DROU-MW-05 4746.6 4746.8 0.20 183,84,1 6.2 Slurry Wall Installation Simulation The Site is planned for a sequence of soil bentonite slurry wall lined cells encompassing the majority of the Site. The only area not planned to be slurry wall lined is the siltation pond in the northwest corner of the Site and a potential recharge pond north of Cell 7. The slurry walls will be constructed in stages starting in the northeast and progressing south then west (see attached Mine Plan for phasing). In order to model for the worst -case scenario, the model includes a simulated slurry wall around the whole section, minus the Siltation Pond area. To make the Site a no flow area, the horizontal hydraulic conductivity of the Site was set to zero (0) feet/day. The area where the Westem Mutual Ditch runs through the Site remained at the 805 feet/day horizontal hydraulic conductivity. The mounding and shadowing for the surrounding properties and wells is described in Table 3 below: Groundwater Model Report— Section 20 Gravel Mine Ode - 7 - August 2022 Table 3 Mining Groundwater Level Table (Slurry Walls In -Place Location Basement (y/n) Baseline After Slurry Wall Construction Difference (FT Rise or Fall) Groundwater Depth Below Surface Surface Elevation (Google Earth) Cell (IJK) Patridge House n 4736.3 4743.2 6.9 20.8 4764 161,135,1 Gine House n 4736.8 4745.1 8.3 20.9 4766 162,132,1 Harding House y 4736.6 4746.0 9.3 19.1 4765 161,129,1 Wiedeman House 13434 n 4738.2 4747.3 9.1 20.7 4768 163,121,1 Wiedman House 13218 n 4738.5 4747.0 8.5 15.0 4762 163,115,1 Sharp House I 5738.4 4745.7 7.3 13.4 3760 163,111,1 HS Land and Cattle n 4732.6 4736.1 3.5 18.9 4755 155,107,1 Karbowski Brave House n 4725.5 4724.5 -1.0 27.5 4752 145,108,1 Schmidt Well NA 4714.4 4709.6 4.8 23.4 4733 132,112,1 United Well NA 4712.0 4706.7 -5.3 41.3 4748 132,126,1 Owens Well NA 4714.2 4711.2 -3.0 34.8 4746 132,133,1 Wright House y 4717.4 4712.2 -5.2 39.8 4752 135,132,1 Schmidt House n 4718.4 4717.0 -1.4 31.0 4748 135,135,1 SmitHouse y 4718.8 4718.4 -0.4 29.6 4748 135,136,1 Kissler House y 4729.5 4733.3 3.8 21.7 4755 148,137,1 Woolverton House y 4730.8 4734.9 4.1 27.1 4762 150,136,1 Shimon House y 4733.0 4737.9 4.9 21.1 4759 154,136,1 Ken House y 4733.8 4739.0 5.1 21.1 4760 156,137,1 Rainbolt House y 4735.9 4742.2 6.3 22.8 4765 161,137,1 Gilcrest Valley HS NA 4737.0 4740.7 3.7 5.3 4746 170,155,1 As noted in the table above, groundwater elevation impacts from the installation of the slurry walls will be highly spatially variable. The southeast corner of the Site is expected to see the most amount of mounding, up to 9.4 feet above baseline levels. However, the groundwater table in this area is very deep (from 27 to 30 feet deep), so flooding is not expected to be an issue. Mounding decreases on the upgradient side from east to west, with the Sharp house on the southwest corner of the Site potentially seeing 7.3 feet of mounding. Elevation from Google Earth for the Sharp property is approximately 4760 feet which would put the potential groundwater rise at fourteen (14.4) feet below the surface. Potential shadow effects from the slurry wall are present north of the Site (downgradient). There are three (3) wells on the north side of the Site which will be in the groundwater shadow and changes in depth to groundwater vary from three (2) feet lower to five (5) feet lower for the United well. The shadow effect is likely mitigated by the proximity of the slough to the north of the Site and the infiltration ponds to the northeast of the Site. The modest shadow effect should have limited effect on the productivity local alluvial wells. The Town of Gilcrest is located between the Site and a rise in the bedrock elevation to the east which acts as a no flow boundary. It is anticipated that slurry wall construction will restrict flow to the west of Town causing elevated groundwater levels in Town as noted for "Gilcrest Valley HS" in the table above. 6.2.1 Monarch Mountain Minerals and Aggregates Site Impacts In addition to the Section 20 Gravel Mine, the Monarch Mountain Minerals and Aggregates (MMMA) Monarch DENM Gravel Mine is permitted by the DRMS on the west side of Highway 60. This site is comprised of four (4) slurry wall lined cells and three (3) unlined cells along Highway 60. To simulate the four (4) lined cells, the horizontal hydraulic conductivity in these areas was set to zero (0). To simulate the end stage of the mine it was anticipated that the Groundwater Model Report — Section 20 Gravel Mine Site - 8 - August 2022 Freshwater and Siltation ponds would be filled in with overburden at the site which would lower their horizontal hydraulic conductivity to be similar to the Eolian deposits in the area. The horizontal hydraulic conductivity in these areas was set to 65 feet per day. The additional impacts from adding this site to the model are presented in Table 3a below and a layout of the site is shown on Figure 5 and 5A. Table 3a Mining Groundwater Level Table With Monarch DENM Site (Slunv Walls In -Place Location Basement (y/n) Baseline After Slurry Wall Construction Difference (FT Rise or Fall) Groundwater Depth Below Surface Surface Elevation (Google Earth) Cell (IJK) Patridge House n 4736.3 4745.5 9.2 18.5 4764 161,135,1 Cline House n 4736.8 4747.7 10.9 18.3 4766 162,132,1 Harding House y 4736.6 4748.8 12.2 16.2 4765 161,129,1 Wiedeman House 13434 n 4738.2 4750.8 12.6 17.2 4768 163,121,1 wiedman House 13218 n 4738.5 4751.2 12.7 10.8 4762 163,115,1 Sharp House y 4738.4 4750.9 12.5 9.1 4760 163,111,1 HS Land and Cattle n 4732.6 4744.7 12.1 10.3 4755 155,107,1 Karbowski Brave House n 4725.5 4731.5 6.0 20.5 4752 145,108,1 Schmidt Well NA 4714.4 4710.4 -4.0 22.6 4733 132,112,1 United Well NA 4712.0 4707.0 -5.0 41.0 4748 132,126,1 Owens Well NA 4714.2 4711.7 -2.5 34.3 4746 132,133,1 Wright House y 4717.4 4712.8 4.6 39.2 4752 135,132,1 Schmidt House n 4718.4 4717.7 -0.7 30.3 4748 135,135,1 Smit House y 4718.8 4719.2 0.4 28.8 4748 135,136,1 Kissler House y 4729.5 4734.8 5.3 20.2 4755 148,137,1 Woolverton House y 4730.8 4736.5 5.7 25.5 4762 150,136,1 Shimon House y 4733.0 4739.7 6.7 19.3 4759 154,136,1 Kem House y 4733.8 4740.9 7.1 19.1 4760 156,137,1 Rainbolt House y 4735.9 4744.4 8.5 20.6 4765 161,137,1 Gilcrest Valley HS NA 4737.0 4742.5 5.5 3.5 4746 170,155,1 The addition of the full build out of the Monarch DENM Site increases mounding on the southern side of the Section 20 Site by limiting groundwater flow to the west. Slurry Walls along Highway 60 and the addition of the Monarch DENM Siltation and Freshwater ponds creates a groundwater corridor along Highway 60 north to the South Platte River, which causes the groundwater at the HS Land and Cattle building to rise approximately twelve (12) feet from baseline conditions. 6.3 Mitigation This section describes potential mitigation actions to decrease the mounding affect of slurry wall construction on the surrounding properties and the Town. The Monarch DENM Gravel Mine timeline submitted to the DRMS was utilized in conjunction with the Section 20 expected timeline to determine the phasing of mitigation construction. These timelines are approximate and are subject to change which may necessitate early construction of mitigation structures depending on measured groundwater conditions at the Site. The shadow affect to the north will likely be minimized by the proximity to the unnamed slough and the infiltration ponds to the northeast of the Site. During mining at the Site, an unlined siltation pond will be present in the northwest corner of the Site which will also mitigate some of the shadow affect. At this time no mitigation is recommended to address shadowing to the north unless groundwater monitoring demonstrates that the drop in groundwater head elevations is larger than anticipated. Mitigation would be warranted if any of the three well owners to the north complain about Groundwater Model Report — Section 20 Gravel Mine Site - 9 - August 2022 decreased pumping rates or their wells going dry. This is not anticipated because the modeled saturated thickness of the alluvial deposit is still eighteen (18) to twenty (20) feet at full buildout of both sites. The groundwater table to the south of the Site and underlying the Town of Gilcrest is anticipated to rise as a result of the full buildout of the slurry walls at the Site and the Monarch DENM Site. Mitigation for mounding is warranted at the southern end of the Site. The mounding is expected to be greatest towards the southwest corner of the Site and decreases to the east at full buildout. Mounding of more than two (2) feet at the south site perimeter, monitoring wells MW -5 and MW -6, coincides with an approximate one (1) foot rise in town. To mitigate against possible groundwater elevation rise in town, a two (2) foot cut off was used to implement mitigation at the south site boundary. Mitigation was modelled in two (2) phases coinciding with the construction schedule of the Site and the Monarch DENM slurry walls. The first phase is an underdrain or series of dewatering wells along the eastern half of the site parallel to Weld County Road 42. The second phase is the construction of an underdrain between Cell 6 and the Westem Mutual Ditch west of where the ditch crosses on to the property to approximately 200 feet east of Highway 60. 6.3.1 Phase 1 Mitigation Mounding at the southern end of the Site boundary and in Town is not expected to rise more than two (2) feet before the construction of the Cell 4 slurry wall so mitigation is not warranted until the Cell 4 slurry wall is constructed or Site monitoring observes a higher than anticipated groundwater elevation at the southern monitoring wells(MW-5 and MW -6). See Table 4 below and Figures 8 and 9. Table 4 Base Model and Modeled Site Groundwater Level After Cell 3 Slurry Wall Well Base Modeled Cell 3, 4 and 5N Slurry Wall Difference Cell (IJK) MW -1 4,726.9 4,726.4 -0.5 146,111,1 MW -2 4,717.8 4,716.0 -1.8 136,119,1 MW -3 4,725.0 4,725.8 0.8 142,136,1 MW -4 4,732.5 4,734.1 1.6 153,136,1 MW -5 4,736.7 4,736.8 0.1 162,133,1 MW -6 4,738.4 4,737.2 -1.2 162,115,1 MW -7 4,729.1 4,728.2 -0.9 148,122,1 BBA-MW4 4,741.3 4,740.9 -0.4 148,122,2 BBA-MW11 4,737.1 4,737.5 0.4 148,122,3 BBA-MW18 4,738.6 4,738.9 0,3 148,122,4 BBA-EC 4,732.5 4,732.9 0.4 148,122,5 A series of wells were modeled at the southeastern corner of the site after the addition of the Cell 4 slurry wall and the Monarch DENM Cell 1 slurry wall. These wells were set to pump 2.25 cubic feet per second(CFS) and removed the groundwater from the model simulating return flow back to the river. Table 5 below shows the groundwater head elevations at the monitoring well locations for this model iteration. Groundwater Model Report — Section 20 Gravel Mine Site -10 - August 2022 Table 5 Base Model and Modeled Site Groundwater Level After Cell 3, 4 SW with Dewatering Wells Well Base Modeled Cell 3 and 4 Difference Cell (IJK) MW -1 4,727.1 4,727.5 0.4 146,111,1 MW -2 4,717.9 4,716.8 -1.1 136,119,1 MW -3 4,724.9 4,726.0 1.1 142,136,1 MW -4 4,732.5 4,733.6 1.1 153,136,1 MW -5 4,736.7 4,736.0 -0.7 162,133,1 MW -6 4,737.7 4,738.2 0.5 162,115,1 MW -7 4,728.9 4,730.7 1.8 148,122,1 BBA-MW4 4,740.3 4,740.5 0.2 148,122,1 BBA-MW11 4,736.9 4,737.0 0.1 148,122,1 BBA-MW17 4,734.4 4,734.5 0.1 166,164,1 BBA-MW18 4,737.3 4,737.4 0.1 148,122,1 The quantity of water required to be pumped or gravity drained away from the southeastem corner increases as more slurry walls are constructed. After Cell 5N is constructed, the modeled pumping rate was increased to 2.5 CFS spread over three (3) wells to maintain pre -slurry wall groundwater elevations south of the Site (see Figure 10). The modeled pumping rate was further increased to 3.25 CFS with the addition of Cell 5S. 6.3.2 Phase 2 Mitigation The mitigation in Phase 2 was modeled to be completed concurrently with Cell 6. This included an addition of an underdrain in the southwest corner of the site between the Westem Mutual Ditch and the Cell 6 slurry wall. The pipe invert elevation for the underdrain was set at 4,735 feet in the east and 4,733 feet in the west. This section of pipe was modeled to remove water from the model to simulate piped gravity flow to the river. The modeled quantity of water that was removed by the drain was approximately 3.3 CFS (287,344 cubic feet per day) at full buildout of both sites. An underdrain was included at the Monarch DENM site between the Cell 3 Slurry Wall and Weld County Road 42 to account for MMMA's contribution to mounding in the area. The pipe invert elevations were set at 4,733 feet in the east and 4,732.9 feet in the west and removed approximately three (3) CFS from the model. Table 6 depicts the groundwater levels for the surrounding properties at the full buildout of the site and the site layout and phasing is shown on Figure 6 and 6A. Groundwater Model Report— Section 20 Gravel Mine Site -11 - August 2022 Table 6 Base Model and Modeled Site Groundwater Level Full Buildout Both Sites Location Baseline Full Buildout and Mitigation AI SW) Difference From Baseline Conditions Patridge House 4736.3 4736.0 -0.33 Cline House 4736.8 4737.3 0.50 Harding House 4736.6 4737.8 1.25 Wiedeman House 13434 4738.2 4739.6 1.40 Wiedman House 13218 4738.5 4738.1 -0.40 Sharp House 4738.4 4738.0 -0.44 HS Land and Cattle 4732.6 4732.1 -0.50 Karbowski Brave House 4725.5 4722.9 -2.55 Schmidt Well 4714.4 4708.9 -5.54 United Well 4712.0 4706.3 -5.69 Owens Well 4714.2 4710.2 -4.00 Wright House 4717.4 4711.1 -6.30 Schmidt House 4718.4 4715.3 -3.10 SmitHouse 4718.8 4716.5 -2.30 Kissler House 4729.5 4729.4 -0.10 WooHerton House 4730.8 4730.7 -0.10 Shin. Howe 4733.0 4733.1 0.10 Kem House 4733.8 4733.9 0.10 Rainbolt House 4735.9 4736.0 0.08 Gilcrest Valley HS 4737.0 4736.6 -0.37 6.3.3 Mitigation With Recharge It is not expected that the drop in groundwater head elevations to the north of the site will have a negative impact on the property or well owners in this area because the saturated thickness after full build out of both sites was between eighteen (18) and twenty (22) feet at the approximate well locations. If there is a complaint from the property and/or well owners, a recharge underdrain or recharge pond will be constructed north of the site (see Figure 7). The groundwater from the underdrain and/or wells to the south will be piped from the southern end of the site to the north underdrain or recharge pond to mitigate the drop in groundwater head elevation. The water would drop into a five (5) acre infiltration pond approximately twenty five (25) feet in depth north of Cell 7. The infiltration pond would be completed in native aggregate. Figure 7 depicts the modeled layout for the infiltration pond. The infiltration pond was modeled using the Recharge Module where a recharge zone was set at the approximate location of the recharge pond. The recharge rate was set to 1.45 ft/day which added 562,089 cubic feet per day into the water table and had the following effects on the wells north of the site: Table 7 Recharge Through Infiltration Pond Option Location Baseline With Recharge Change Schmidt Well 4714.4 4713.4 -1.00 United Well 4712.0 4714.0 2.00 Owens Well 4714.2 4712.3 -1.90 Wiedeman Well 4717.4 4716.6 -0.80 Groundwater Model Report— Section 20 Gravel Mine Site -12- August2022 The model was utilized to determine options and feasibility for mounding and shadow mitigation structures and are not final design. The baseline groundwater level is based on eight (8) months of piezometer readings taken at the site and further water level monitoring should be taken into account during design of the final mitigation structures. 7.0 CONCLUSION Civil Resources makes the following conclusions and recommendations based on the modeling: ➢ An underdrain or series of wells will be effective at minimizing the groundwater elevation rise south of the Site, and similarly the Gilcrest area, by removing water from the aquifer and rerouting it around the Site to the South Platte River via the unnamed slough west of the Monarch DENM Site. At total site buildout, including the Monarch DENM Site, the quantity of water to be piped to the river would be approximately 6.5 cubic feet per second. ➢ If the shadow affect to the north causes negative impacts to the wells north of the site (Schmidt and Owens wells) then a recharge drain or recharge pond could be constructed to the north of the site which would be effective at mitigating the shadow affect. ➢ The models and data presented in this report are based on eight (8) months of piezometer data collected at the site. Further groundwater monitoring of baseline conditions and after slurry wall 3, 4, 5N construction will be necessary for designing the size and invert elevation for the underdrain or spacing for Dewatering wells. ➢ Since groundwater is expected to rise(mound) south of the Site the mine operator will continue to monitor the existing monitoring wells in accordance with the Groundwater Level Monitoring and Mitigation Plan, included with this report, to catch any mounding or shadow effects at the Site before it become an issue to the surrounding properties. 8.0 BIBLIOGRAPHY Anderson, Mary P., "Applied Groundwater Modelling, Academic Press Inc., San Diego CA, 1992. Bishop-Brogden Associates Inc. & JVA Consulting Engineers, "Dewatering Improvements Study for the Town of Gilcrest Colorado," 2016. Colton, 1978, "Geological Map of the Boulder, Fort Collins, and Greeley Area, Colorado," U.S.G.S. Map I -855-G. Das, Braja M., "Principles of Geotechnical Engineering, Fourth Edition," PWS Publishing Company, Boston, Massachusetts, 1998. Fetter, C.W, "Applied Hydrogeology Third Edition,"Macmillan College Publishing Company, New York, 1994. U.S. Department of Agriculture, Soil Conservation Service, 1988, "Colorado Irrigation Guide." Waskom, 2013, `Report to the Colorado Legislature Concerning HB12-1278 Study of the South Platte River Alluvial Aquifer," Colorado Water Institute. Groundwater Model Report — Section 20 Gravel Mine Site -13 - August 2022 Figures eIG 7?OCPSOt. r GRINEi IIWCI SECTION 2C ::MvtLMlr! 7�1 MODEL 110UNDAfit ItCROCK CONTOURS OuliCE WELL PERMITS AND Wilt LOGS ISEE A➢PEN01x R82 l w.. wtul % below. Call bclote you dig ( I V I I Fit S <( t. I i 323 Sth STREET P.O. Box 680 FREDERICK, CO 6USJO 103.81) 1416 WWW.CIVII RESOURCE S.COM RED TIERRA EQUmES, LL' ',O RTC I t. ►RtNTZCL AVE I IC0 GRtf4W000 VItLAGt. CO ICI I : REVISION'. DESCIU►TI0N !j QA1t (-1fric21 CAAWN Iry S. L Watt (4 NOTEQ— CMEINI0 ft all. AS PA: != KW NO. 141AQ1S4 cwG AAMe SW MOOtI. tk112022.Op REGIONAL BEDROCK SURFACE 1 rA,ter atr.110si :6 MODELROUND/MY SOUTH PLATTE RIVER HEAL) AANL, RIVER SEC BASED ON USGS 1OIC/. ++�I CONDUCTANCE 15u 1& INCAEASTMi DOWNSTREAM AS RIVER WIDENS I NR E 4NAL 80UNCARY CONDITION / RIVER. • WESTERN MUTUAL, PITO' I CONDUCTANCE UPSTREAM 6 FT/DAY i10WNSTR E AM ; , T1'AY HUNT RECHARGE PONDS. RATE O.G15 FT/DAY YEARLY RECHARGE UNKNOWN WEIOEFAN RECHARGE VONI. RATE RDA FT/DAY it 31 ANNUAL. PErHAGGF • PATE L+..L; I', (it" :013 ANNUAL FECHARG, f:2.4 AC•PT HUNT REUMMGE PONDS RATE D•lu7 TT/DAY ,ICU? RECHARGE PONDS PATE U.015 FT/DAY ESTIMATED ANNUAL RECHARGE KAREN RECHARGE POND RATE U,L175 FT/DAY 2017 ANNUAL RECHARGE L26( AC 41 04josim POND RATE 0.015 F1'/DAY 11:13 ANNUAL RECHARGE 71.} AC "'-• SCHAFER RECHARG - rowdy RATE 0,01518/DAY IL 1 S ANNUAL. R rcHARC,F. It' INTERNAL 00lINCAPY CONDITION RIVER - PLATTE VALLEY DITCH CONDUCTANLE 7.5 FT/DAY SPEARED ►ofeA6OUNDARy AP. to' eig,APPROX. ID' BPS SURlACE MODEL BOUNDARY NO PLOW COUNDARY WHERE TOPOGRAPlgq RISES AND WELLS GO FRUN COMPLETED IN ALL1fIAL AgvIFEP TO COMPLETED IN CONFINED AQUIFERS IN IERNAL bOUK,DARY CUNUITION RIVEF - EVANS £ 2 CONDUCTANCE )4 FT/DAY WWERLATHAM RESERVOIR Knurl Mutts i1H10W. Call before you Mg ( IVII RES�UR( 323 5Th STREET P.O. Box 680 FREDERICK, CO 80510 303.8 7:1.1416 W WW.CIVIL RESOURCE S.COMI RED TIERRA EQUITIES, LLC NMI E. PRENTICE AVE ' 100 (ARLENWUUU VILIAGt. CO WI I GROUNDWATER MODEL SECTION 20 GRAVEL MIN GILCREST CO REVISIONS DESCRIPTION DAM GESIGNEO BY l651 DRAWN BY Asik CHECKED BY Auk 708 Ntl. 30),VML44 DWG MANI;GW MODEL IU1120TZ•0w GAIL /-20-10,1i SCALE RS NOTED A5 NOTED BASE CONDITIONS 2 MONARCH UEN 1,PL %it t. MINE EL P170 . SECTION l0 GRAVEL MINE 71u PT/D 65 FT/0 4.1.10 S. Corieal <.tV'II RES.1U 323 5th STREET P.G. Box 680 FREDERICK, CO 60530 303.8 33.1416 W WV1.CIVIIRESOURCE S.COM RED TIERRA Fcul IFS, LL.C. MOUNDING SHADOW MODEL SECTION 20 GRAVEL MIN GILCREST CO REVISIONS Iti4 DffCRIP1ION DATE CESIGNEC BY DRAWN 9Y III {rtCxED IV AUL 108 NO. 1(1)JICUII DWG MME GW MODEL IC111D21.9wa DATE: 1.1D-4 2Z SCAIFAS NOTED AS NOTED HORIZONTAL HYDRAULIC CONDUCTIVITY SHEET 3 dig. E14Il RFS418I,-( 1 321 Sih STREET P.O. 80K 680 FREDERICK, CO SOS SG ]03.811.1416 W WW.CIVILRESOURCCS.COM RED TIERRA EQUITIES, Lit ICI C. ►RENTICE AVE *100 GREEMYOO0 Vk/AGt, CO %GI:; MOUNDING SHADOW MODEL SECTION 20 GRAVEL MIN GILCREST CO A£V1l1 W.-. NW 6KCa:tTKIN .t-i1GPet NY 45a. '.)SAWN fY jg. CliEDI(08Y ALL JON NM 302.001.0 OATS L1k1G2L_ SCALFN NOTE➢ A6 KITED cwG N*MEuW MODEL 1f12C1Loaa_ EXISTING CONDITION CONTOURS 4 II I INFILTRATION PONDS 1 I sMS Sw00 a a 1 1 1 I 1 1 E I I. • 11 I F I ;1 II li li Ia no f: tB>• Iti B71 B11i 8� i a ti a I I I I I • , KASIRCENSAI/eILAVE POL.:.. • GRAVEL hii. 1 II I.. J11 II t I II Up —1 it I iiy. 1 r� 1 i ♦�-- _- L 11 ILS LIVID Aft CATTLE .r .tti — ti ISM — — MSS MIN WELL es a—atwa pp---••N.M• Me a ma ma M• I i S MN•1 IRSERVED 4775.4 MDOELED 4737.1 .._.N._.. —MS= SHARE HOUSE SECTION x GRAVEL KW MW -7 Oe5ERVID:4734.9 MODEM: 477Y.9 f • S S WleoeflW NOUSE WIEOEYMN MOUSE HAROING HOUSE MW -5 OISMVID: 4776.4 COMM 47)6.7 Know white below. Call before yuu asy. Sal OBSERVED. 4737 M00fLEC 4736.9 l 1, RESIPURl I S 313 5th STREET P.O. Box 660 FREDERICK, CO 80530 303.8)3.14 16 W W W.CIV IL RESOURCE S.COM 8301 E. PREN:TICE AVE 4 ICC GREEMV000 VILLAGE, COOCt11 REVISIONS DESClU►1'IOb 0ATt i•IL-Asti SCALEAS NOTED AS NOTED 3O,3 NCl tin .X1.C4 CWG NAME GW MODEL 10112022, wa EXISTING CONDITION CONTOURS ' -1.1 **4. Klswr what's below Call baton you dlq. CIV1t RES UK 323 5th STRkET P.O. Sot 680 FREDERICK. CO 80530 )03.83).1416 WWW.CIYII RFSOURCES.COM RED TIERRA EQUITIES, LAC *ME mama AVE . t00 GREEM4000 V1u•.CE. CO SG I I MOUNDING SHADOW MODEL SECTION 20 GRAVEL MIN GILCREST CO .tlfWOIL. DESCAIDTI0N DATE CESIGML P GRAVEN AY yam, CHECKED M La !C6 N0. IC 1.001.04 WG NA t..4tt_M0Di:_.:411tC22 *a DATE 1.2G•1C22 SCALE it} CEO M kOltO SLURRY WALL FULL BUILD OUT CONDITION CONTOURS 5 u • ♦ 411 IA ♦ - ♦ I 1 1 I 1 1 1 I 1 1 I 1 1 1 I 1 1 I I .- 1 1 MO/NRCXI Dt •. 1 GRAVEL HIP. 1 I 1 1k: LANC AND CATTLE 2.3' MOUNDING 1 I ,..__ a +IIMaNINOO r i I 1 1 1 1 1 1 1 1 1 1 I I I I 1 1 i MI IN!' IIIIII- t11A s t111• - Ill• SiliAINS.ca•'•• SHARP souse S.8' MOUNDING ONENS WELL -IS SHADOW JARRED WEll. 4.3 ShKDOW a s- S S a a a- SS a a a a a s a a r I • ..... ...-.. s .re• 1 i • • • • • • • i •• WIEDEMAN HOUSE 8.1' MOUNDING ti • • - • •• • • •• • • • • • • •• ♦ • • r — 4 • • • • • • o. • S. • II I I CEO. S5 MODELED SLURRY WALL LOCATION WIEOEPIAN HOIKE I.S MOUNDING ' a a a S a CUNE HOUSE 7. r MQUNDIpG • ISSLER MOUSE 4 C MOWNJINO WOOLVERTON HOUSE 4.1, MOUNDING PATRIOGE HOUSE 6.7' MOUNDING GILC*EST VALLEY NIGH SCHOOL 4.o MOUNDING ken , als. C-35) t IVII RES'IUR( '• 323 Stb STREET P.O, Box 680 FREDERICK, CO 80530 303.8 33.1416 W W W.CIVII.RESOURCES.COM RED TIERRA EQUITIES, tic net E PAENi10E AVE *100 GREENWOOD VILLAGE, CO ICI l l GROUNDWATER MODEL SECTION 20 GRAVEL MIN GILCREST CO ALVISIGN} NO DESCRIPTION DATE DESIGNED 8Y ga CRAWS IV S CHEO(ED BY DLt1. !o6 NO 103.00104 :At:. Mk OW MODEL IV112D21,0Ra DATE 1•2D•2G21 SCALEp5 NOTED AS NOTE0 SLURRY WALL FULL BUILD OUT CONDITION CONTOURS 5A MODELED UNOeRDLAIN LOCATION TOTAL WATtA REN0VEC l.ICPS CONSTRUCTEO WITH CELL 6 SW CEWATEAING WILLS IACATiON RROACWDMTE TOTAL WAttR S!_NWED 3.14 CPS O0NST1UCTEC WITH au 4 SW .m. kstn, Whats below. Call orlon dig. l IVII RI S7UIt(FS 323 Slh SIKH I P.O, Box 610 I REOERICK, CO 60S3U 303.6 33.1416 W WW.CIVIL RE SOURCES.COM RED TIER.RA EQUITIES, LLC Slat E. PRINTICE AYE •;�_ GRttWWOOD VILLAGE. CO el: I: MOUNDING SHADOW MODEL SECTION 20 GRAVEL MIN GILCREST CO REVISIONS NO DESCRIPTION DATE DESIGNED RR 1Sa. DRAWN SY• igs. CHECKED IV ELM JOD NO. IO1.00 L.C1 CMG NAM. GIN PlQOLL 1(112022.awo CATE j-20.1022 SCALE AS NOTED AS Ndf ED FULL BUILDOUT WITH MITIGATION 6 • 1 OM II• i II ,0 1 I 1 1 1 I1 l 1 /- ♦ , I / I , I 1 OPTION TO DISCHARGE TO suNicH I I • ts a e I I II 1a n mi111 mie 1n me w a se a a 1 1 1 S i• IDT WELL 55 DROP IS a MEM a a 181 / I / / / I , l 1 I I I I I I 1 1 1 I I I 1 1 1 I MONARCH DE GRAVEL MI HS LAND AND CATTLE Cs DPni, ► EAROI CElul UNDERDRAIN GROUNDWATER NSa1AL RATE Lc as SOUC CSCHARGE PIPE I I a a Ma ti m a m an gm a as m e/ m e a am r a. ••NeM• SECTION D. GRAVEL MINE UNDERD-MN DAP 471S' CONSTRUCTED WITH CELL 6 SW 24' SLOTTED PVC GROL•ICWATER REPONAL PLATE 3.1 CPS INN EL 473r SHARP HOUSE 0S DROP • • MO an S S •• •• er a a •• • s• I I I I 1 1 I $ 1 1 1 1 1 1 I 1 1 / a Il�ae ►rar.� 1 MODELLI.OtWAttliM, wEt.L. OR UNCERDRAIN GROUNDWATER REMOVAL 3.25 CRS OOHSTRUCTED WITH CELL 4 SV. a a an • LOCATION HARDING HOUSE 1.3' RISE —1- S.• 1 I KISSLEII HOUSE C.1 ORO, 911MON HOUSE C.r RISE IWNBOLT HOUSE 0.1' RISE GIICREST VALLEY HIGH 5OA0i D.4• DROP r X14 Rkti1URE IS 313 SDI STREET P.O. Box 680 FREDERICK. CO 80530 303.813.1416 W W W.CIV ILRESOURCE S.COM RED TIERRA EQUITIES, LLC 5701E PUMICE AVt '100 GREENWOOD VILLAiE. CO tic lit GROUNDWATER MODEL SECTION 20 GRAVEL MIN GILCREST CO REVWONS NO DE'SCRIPTIts DATE : si NE.r, eY Sa CMWN WI at. CrtEC11ED 5Y 1111. 708 NO 101.001.04 UA;t 1 ` SCALE'S NUtEO AS NOTED CwG wANEGW MODEL 1C113G22.O.w SLURRY WALL WITH DRAIN CONDITION CONTOURS 6A ' ' f` - tiLV . - `f x - STEEL WELL LOCKING SGiMiCT WELL : ]4.0 •2U.0' (�.0 UD SASE MEAD EU 4711,4 , BFL� MEAD EL. 4714.2 ' DROP' 1.4 HEAD EL 4; I7A BA OWENS AD DROP' 1.4 .. II(I•� 1 SLURRY WALL PLATFORM r 1 C‘)ID - 1 ►ITLISS ADAPt ER MITIGATION l3 471).4 OP0.4HEAD DROP a.lr —{ lac t V I I I RE S'SU K L. E S '' VARIES . 1 I ' ) MI NE/RC{UMATION r 323 Sly STREET �' 1 SLOPE P.O. HOZ E40 - • 1 FUTURE SLURRY WALL FREDERICK, CO SOS it.: 14• PVC UNDERORAIN 30 1.833.1416 501WN SAN= = r WWW.C(VILRFSOURCES.COH 1 OPEN BOTTOM WITHAWRPGATE BFLClNG • i � � A UNDERDRAIN TYPICAL SECTION -V rO.S•iJ _ - ) t 30- DIAMETER I 0.37S" WALL THICKNESS STD - • 0 1 r �) �r STEEL CASING •• ..1 _- 1 BEM11! — ME s 1 a Ma Me a a s »' - +O.S' • t 1 4 I 1 1 16 DIAMETER BOREHpIf fO0. S�,1 1 r••1••L•4� r•..u•r- I-! l ••r• j-- " S•••a,••••- ••A....•,` 1 -�..P1[.3e.+____— "-�-.y.� •' - - - 7' • 11 CE#1ENT 1 24 RECrARGE uNCtPDRAUJ :4- hEf11ARGt UH,UE;CRi1N ON EL 4721 • .. EXISTING GRADE ) 1 Inv EL a:r 1 1 . N -II>✓ t� L^ -1L 1hD^ RED TIERRA EQUITIES, LLC 1 _ 1 t ® , iii- i �f��- I 1 • J� iL,1t I[L - MI E. PR,ENTICE AVE • 100 1 1 1I. OPTIONAL LOCATION OF RECHARGE POND I •1 1 L OSHA SATE SLOPE/STABILIZATION �IP GREENWOOD VILLAGE. CO BC::: J ✓ - - - �IOCAnHIG TAPE - S.., ' .�� 6ACKF:L_ COMPAQ ED TO IS%OF STANDARD MOD PER 0618. • .O.S - BOTTOM 1 1 1 _ . 1 - _ - ; .. I 1 - ASTM 18- pIAMEIER O.17S WALL THIOOIESS 1 STD STEEL CASING 1 1 - ri I 1 , TRACING WIRE 15 17. 4ENTON[TE PLUG 1 1 .1 - .-- 11"•T4' PERFORATED PIPE / 1 Q44 1 • 1 (SUBMITTAL REQUIRt01 / 1 �. • 11 X7.8 z 1 ..: I i .• ( SOLID DISQARGE PIPE =8 ROCK APPROVED BY ENGINEER AND .J .--4 I 11 . UJ DELIVER/0w OWNER.5 l rm 1 1 UNDWATER MOE [ON 20 GRAVEL GILCREST CO 1 11 1 I B 1 I , ' I g UNOERORAIN TYPICAL TRENCH SECTION 1 1•_ "- — t 7 I (.,,n 4lm 1 11-———- — { 1 1 1 :.., I'' ) i 1 i 1 _ 1 •1., 1 t I 1 1 .. 1 I Ai 1 1 1 t ' 1 It 0.:SC-IN SLOT STAINLESS I 1 t ...•.r.r•.• I Stm • 704 WELL SCREEN r / _ / 1 _ I 11 f,•• I 1FREQUENCY 1 P• / VARIABLE 1 I -� -- / •• - - - - - -- - IVEMA DRIVE/ SUPPORT ObA . BOX ANC147ItE0 IN COIICIIETE PA) D IN axon -u.- DISCHARGE LINE 1 1 • 1 II 11 1 — I 1 �I 11 / REVtSIDN6 1 1 / 2.0 24 VNDtJWMIN INV EL 4733' •• 1:-03SCIAR6EPIPC 1 - I I II I r . • NO - DESCRIPTION OA1E i 1 • I D15C►ARGE ),J CPS _ • -yip- - 1114(I, 4 . MP RAPPAL vT, IS HP I 1 I II 1 roDAOI W PUMP (00. APPROVED tQWL, (O I I1 1 - ,., 1 1 µ� 1 L ._•_„ 1 a GNAVEt PACK 4 :�'i '� ■ 1 TYP. I a �_ a a �-� a aa -----_a---- a ------I - - l' 1 -, :C' DIP ~ O • 4 • I11V EL 4732 - • V 14 I II ., a,..� —�_ - .. - - DEWATERING VUF+IPS - OR UNGERURAIN DISCHARGE ),2505 - surPoar eRAa:tis ANCHORED IN CONCRETE PAL NTT) OR MANUAL START II r. • 10 SUMP • - a DESIGNED BY 619. -r DATE 1.20.2022 - .• - DRAWN BY la iCALEJS NOTED ' BY l AS NOTED .. --tHEOCED a ti QL 308 NO. )G].O191.001,G4- CWG NAME LW MODEL 10111a2I,4v>a _ - WELDED STEEL RASE _ Li PLATE 10' DIP Q SLURRY WALL • PIT _ DRAIN WITH 8j1 RECHARGE DIP Vat(TICEPT ON BURIED / \ 1ST WELL INSET) CRICK / D DEWATERING WELL 7 y •• YHC!! $*nowNTii:tS below. below. y Call before you dig. i + C OEWATEItING WELL DETAIL I M % 7 �� _ S r '� 1 'a ' 1 I 1 • r , + _U I 4v C R 44 -L-� , 1 1 i HA... Lr :- - J ri r r r w. �. I_ .-' If_ r ... in -kI I ,, 1 I CELLS II iir I 1 1 f I , 1 f f I I 1 1II 4725 ti II +-El -k- I 1 X li f I i 4-1-i-if -I- I ir --i-- 1 1 i li +�- -- I r 4 4- fi ,t e• --i- -f.. ��+� --1-- �TI�I I I SECTION 20 { +� 1 j1 ---II � - r , MONARCH DENM I +, , 4 -4 -±---1-- _4 1--' . I/ ."--1 41 i I 1 1 III I I w ^ r . a ■■ T �--- --i--1 t r-. II I t - 1 1 rN �TT� a- U -fi- Cr-r--CH' f -- __l___i_H__ i,,,,„�. W C R 42 1� ---- ■■■ ■�■ ib■�■1■■�� —..un ■r■r■■■ -1-' WESTERN MUTUAL DITCH _r4_,_i_-- I AN " _■■■■ ■■■ ■■■■ ■�i■■ ■■ -- ri■■ -,-- Wi 1-1-1\ I\ ( i 1 NOTES: 1. THIS MODEL ITERATION INCLUDES A SLURRY WALL AROUND CELL 3 2. NO MITIGATION IS MODELED IN THIS ITERATION SECTION RED TIERRA 20 GW EQUITIES MODEL DATE: FIGURE: 8 HEAD CELL CONTOURS 3 SLURRY WITH WALL Orttavitter, LL ` -� ' l- � -- -� I 1 � ` v1 C R 44 N A. r -44-x- sin-hi f-J -, �. . 4 -al. - - L. _ - _ - - -. _ _ _ "tfr4 . 1- 7-. I I l�- ffp 4% ' 1 ---I- QsIr �. �� . 1 I Ii I' ! I I I 1 � � CELL3 :11 i� i 1 1 i pH- ii 1 i Iire I I I - _,� _h_t___4__ .I i it IIII _ /( 12-Htd i I t-HuHIJ"IHr CELL 4 ' SECTION 201 , I it t- 1-- ---1- r, F- IT t- i , , , TO _44_ H- I fit �/,, ,i DISCHARGE I i' ! 11{ I___,_,__L___.__,_, I 1� i --7 yIsLouGHI!titl�b4UIbI f 1. 2444 1 _i_l__L H___ 1 a 1 I I a I MONARCH DENM I 1 ■ '� -1---,p-i-4- ------�--�- _ GRAVEL MINE 1 II I ■ I / Ul r44-1-4---i-j-'± 1 li . •■ ■ I I 0.4' MOUNDINC. 1 f : / y I �- �- eni C 1 I _I_ 7 I -A___1 I Y I I_ ��..� i .� ■ ■■■ill ter.■is ■■■■■ _ I , , mg "Sit IllJUPflhIWUSflhirnTI■■1 ■■Neill■■■r� _as! _tea ■■ - ■■■■■■iiiSaill ■ ■Ind CIS■rte t rs is M� - ■■■ - ■pea -��p. UNDERDRAIN DROPS INTO morn. 4 III._ MEOW EOW I NVi■■■■ME■■■ ■I ^ 5 DIAMETER M H ` MW V -5 Pill ■■■■■�■■■■■■ I I .! 0.4' DROP _arid _-_--. 4740 1 l l flPail-■��ld■■■��■■■,■ ■ J�_ 24" UNDERDRAIN -- I,li■C ■■WW�■■■MEMO ■■=-- �■ DISCHARGE 2.0 CFS manilla i ■■�e� OR 174,000 CUBIC FEET/DAY WESTERN MUTUAL DITCH I'm _ Mal il MONARCH I di I. -i -. �` I 'I CELL 1 EL. Illlar L., „4..,_ .. Slim-. ..- , . ...., , Imp,. , . ,,,..... . . ii _ imi liral II-- -,..4.--i - NOTES: 1. THIS MODEL ITERATION INCLUDES A SLURRY WALL AROUND CELL 3, CELL 4 AND MONARCH DENM CELL 1 2. MITIGATION WAS MODELED AS AND UNDERDRAIN DISCHARGING r RED SECTION TIERRA RRA 20 EQUITIES GW MODEL 2 CFS OR 174,000 CUBIC FEET PER DAY TO THE UNNAMED SLOUGH WEST OF THE MONARCH DENM SITE. DATE: Ott; 7O22 FIGURE: 9 HEAD CELL CONTOURS 4 SLURRY WITH WALL I1'!'1 _ 1 4 j I / e4:1 _,...'''' / � LTDJ_ _irirI I \wCR 44 O . --4-1P-- r ! I V.--.. r -1-' I ( �I 1 1 CELL 3,±-1--, I I 1 J f I i I 1 I �I I I II f i I I I 1 1 ii 1 1 l ? �-_� i _ -I1I - f 1 I I I- /1-17 iI, i- i fi 1 I I it.1I i jLI i i I 4, _,__, i 1 I �� i II _4C CELL 4 Ili SECTION 20 1 O O 'IF I . ! 1 I ri LI 1 ±` J-1" fnh-rnrri± • -- ---}-, --- DISCHARGE �: j I L � } t-L-t ii 4/'fl_TTirrT1 iill I�. F k _fi 1 1 rriett I ' 4-./4,-[ -k-E MONARCH DENM 1 -- CELL 5N 1 rill -f - GRAVEL - MIA- -�- ;-1--1--J 1NE �11 I rz-4-4,--F-1---1-1-4--E- Ilit -I- --V I II 1 tf I ,) [mop 4---. -4,-FH-1---ek- H___ 1 �- r M W - 6 -T- `_ L f I �...r y 1-4 0.2 R I S F -_� I . i �� r I-4 i - L 1 - ---h - ■ ■1 �' ■1 _ I I"■r • �.- i ■,r 4 O ■.•7■1 f .�� W C R 4 2 - -� ` Q` I ___ 3 DEWATERING WELLS -- ,----(J) TOTAL DISCHARGE 2.5 CFS ' T WESTERN MUTUAL DITCH �■■■.■ OR 216,000 CUBIC FEET/DAY T -��-�- _ MONARCH _ CELL 1 1 - ' --- ■ �i■■■■■■■■■ ■■■■■- ••-t- In■■■■■■■■■ ■ rC �` Pr , ce , NOTES: 1. THIS MODEL ITERATION INCLUDES A SLURRY WALL AROUND CELL 3, CELL 4, CELL 5N AND MONARCH DENM CELL 1 2. MITIGATION WAS MODELED AS 3 WELLS DISCHARGING RED SECTION TIE RRA 20 GW EQUITIES MODEL 2.5 CFS OR 216,000 CUBIC FEET PER CAY TO THE UNNAMED SLOUGH WEST OF THE MONARCH DENM SITE. DATE: October2022 FIGURE: 10 HEAD CELL CONTOURS 5N SLURRY WITH WALL -1 .___. _ I 1- 1 I 4 I .. U II Ji 4--4— —+" I I_ I- ■■■■-4 _ -1 —I- tri./'=_1. s S+.47 -1—i 1, /1/i%/.:= ,4Nn\IL -t 1■ I , i`.h`; CELL 3 I .,..r.- ii- il _ _ 1 i ' 4. r ai F Ii , INFILTRATION 1 / MONARCH Ii 1 POND i `.. r ; tI 1 1 i I 1 CELL 4 CELL 4 I CELL 7 SECTION 201 I I �. I i M I I I i -�---+ __ -, i �z MONARCH DENM ifi ; i CELL 5N I Z " *liSOLID PIPE GRAVEL MINE -.► -:- i -4- _, .. T-1 I 1-1 CELL 6Is _ _J >L tsp,aer_. H r 1 MONARCH CELL 3 lam- I �� CELL 5S ..r��.�' I �.� ■ ' -. , MONARCH ■I■■■■■■ ~— �■■■■ it : ! ■ a '.1" - ► ► __ CELL 2 - . __NIA NHOtE W J 3-iii—i 11 1 1 1 _a _i 1 MONARCH II CELL 1 ��.24 r L � 4 L • 65 cc II ' I :Cr NOTES: 1. THIS MODEL ITERATION INCLUDES THE FULL BUILDOUT OF SITE RED TIERRA RRA EQUITIES n SLURRY WALLS IN ADDITION TO THE FULL BUILDOUT OF THE MONARCH DENM °a SITE. SECTION 20 GW MODEL 2. 6.5 CFS OF GROUNDWATER IS COLLECTED FROM THE SOUTHERN END OF THE 5 SITE AND PIPED THROUGH THE MIDDLE OF THE SITE AND DELIVERED TO THE V INFILTRATION POND E NORTH OF CELL 7. DATE: p,r. FIGURE: 11 & INFILTRATION FULL BUILD -OUT POND Appendix A Section 20 GW Monitoring Program P ezometer Information and Water Levels Depth from Top of PVC, feet gate 'easure, - - _ -- - Dulling estimate 11/4/2021 25 24 25 23 14.00 27.00 12/28/2021 26.40 25.50 21.10 28.40 30.2 22.20 28.80 3/16/2022 26.60 25.90 21.40 28.30 30.20 22.00 28.60 5/23/2022 26.70 25.70 20.60 26.20 28.20 20.00 27.80 622/2022 26.70 24.40 19.90 24.10 27.60 18.70 26.30 7/15/2022 28.60 24.40 18.70 24.50 27.20 18.50 26.00 MW -1 MW- ' MW -3 MW -4 4,728.60 MW -5 MW -6 MW -7 4,726.82 4,725.90 4,717.50 4 723.70 4,733.90 4735.3 12/28/2021 3/16/2022 4,725.70 4,717.10 4,723.40 4.728.70 4,733.90 4735.5 4,727.02 5/23/2022 4,725.60 4,717.30 4 724.20 4,730.80 4,735.90 4737.5 4,727.82 6/22/2022 4,725.60 4,718.60 4,724.90 4,732.90 4,736.50 4738.8 4,729.32 7/15/2022 4,723.70 4,718.60 4,726.10 4.732.50 4,736.90 4739.0 4,729.62 Appendix B BBA water consultants B ISHOP-B ROGDEN ASSOCIATES. INC. DEWATERING IMPROVEMENTS STUDY FOR THE Thwn of Gilcrest, Colorado OCTOBER 2016 SECTION 2 - PREVIOUS STUDIES, DATA COLLECTION, AND MAPPING OF DEPTH TO GROUNDWATER PREVIOUS STUDIES AND DATA COLLECTION Previous studies by CGS, Brown and Caldwell, and others were reviewed to identify aquifer and groundwater data available in the vicinity of the Town. The information and data included: groundwater level data, groundwater recharge data, groundwater model input data, mapping, geologic characterizations and other information pertaining to the shallow groundwater conditions within the Town. In addition, we completed a review of groundwater information available from Town staff, Palmetto Environmental, Tetra Tech, Central Colorado Water Conservancy District, the Division of Water Resources, Colorado State University and input from residents and individuals with relevant knowledge. MAPPING OF DEPTH TO GROUNDWATER The starting point for developing the Town dewatering plan is to identify the areas within the Town that are affected by shallow groundwater conditions. Water level data were compiled to prepare maps of groundwater elevation and depth to groundwater for the recent high -groundwater condition. Previous studies have included depth to groundwater mapping, but those studies did not include water level data from the Town's wells and were of a regional as opposed to local scale. Ground level elevation data from the USGS and CDWR, were supplemented with new survey information developed from our own survey and data available from Tetra Tech and Palmetto for monitoring wells located adjacent to the Town. Additional water level data were collected from the Town's existing wells and new monitoring points in and around the Town, identified in Figure 2.1 and summarized in Table 2.1 on the following pages. Water level hydrographs were prepared for each of the monitoring wells relied upon in this study, as presented in Appendix A. Historically, the depth to water within the Town limits has been as deep as 45 feet below ground surface, based on information reported on well permit forms and information provided by the Town regarding sewer line and pump station conditions. The current depth to water within the Town ranges from 9 to 17 feet below ground surface. During 2015, groundwater levels were as shallow as 6 feet below ground surface near Main Street and 11th Street (RE -1 Well) and 4 feet below ground surface near the wastewater treatment plant (located in the northeast corner of Town). The hydrographs indicate that water levels have generally trended down since the monitoring was initiated in 2015; with the water level decline for the approximate 16 -month period ranging from 0.4 to 6.4 feet, and averaging approximately 2.5 feet. 3 R66W .a •�f 4� Y. �r . ,. T 1 //�� .Y ditch .M ♦� I A/ I I✓ e 11)11 • - - -- , Sl r •_ , . I / i I �7,�. _. - .. ••rte _ _ • - ♦ - - '- / e-- 71 / LSP-043 (11324-R) 14969 . I% . : -R -R _ o:., , 4 r ; - WIW 8 I �' .. �� t _ �-, MW ,. _ • :. Lorenz -3 - . • �~ ' ELC W W -114 _ - - st _ •.. 12939-R , •' 'LorenzL!J!j943 Lorenz , > Ili (12938-R) 953 -R -R -. A -.sue .. RE1F� • `' 10943 Z :. NO - 1. r ,' - -F -R I ' {=LSP-102 i.,"' , (246339-A) ..y r Lorenz « (12939-R) . ` Nelson -,-„ . _ . _ r, Lorenz MW _ � -2. .:.. - - - - *I 4838-F WY a vh 1 r 'M . M O 109-3 r 12791 - -R -R : . a / 108-1 - , • 61.32-R r ..... I t — Y l /,rec , J I y , I t , • •" r.. . , � e ,. - / Dt:�,ich I -f _. ►� Gan _ _.._ 00 BBA 1 J _.00.00.s:400L- 0 1,000 2. 00 e' water , a t wa r c�an.utta n .s ( 1 1 1 l t- l I I T L R; unr•fanatliK Ai.001.17ES. EPIC ;03,8116.{952 I www.hhawatcr.cnm Feet :j 4. i 3 _ A • . Legend Colorado r Main FIGURE 2. 0 Ground Water Measurement Location ■ ► 7. Town Gilcrest of .MapI Town Boundary j 1 Ground Water PLSS Section 5 , Measurement Locations Aenal Photo Date: 6/19/14 Date: 9/20/2016 Job No. 1606.00 Data Source Town of G+Icrest, BBA, CDSS, CDOT, USGS, BLM I DRAFT Table 2.1 Town of Gilcrest Well Information in Vicinity of Town Depth Pumping Rate Static Water Static Water Name Permit No. Registered Owner (ft) (gpm) Level (ft) Level Date Q40 Q160 Section Township Range Town of Gilcrest Pumping and Monitoring Wells Nelson 16163 -F -R Henry Keiser 92 1000 30 5/12/1955 NE SW 28 4 N 66 W 5th St. 12390-R Western Wholesale Produce 90 500 15 10/23/1945 NW SE 28 4 N 66 W M+E 13119 -F -R Town of Gilcrest 95 800 22 3/23/1970 SW NE 28 4 N 66 W RE1 59739-F Weld County School District RE1 60 - - 5/1/1951 SE NE 28 4 N 66 W TH 13118-F Town of Gilcrest 90 800 35 5/1/1956 SE NE 28 4 N 66 W GMP 47041-F Town of Gilcrest 92 700 20 9/26/1996 NE NE 28 4 N 66 W W/W 117787 Gilcrest Sanitation District 31 - 13 12/12/1980 NW NW 27 4 N 66 W E/C 117788 Gilcrest Sanitation District 31 - 13 12/12/1980 NE NW 27 4 N 66 W S/C 117789 Gilcrest Sanitation District 31 - 14 12/9/1980 NW NW 27 4 N 66 W Lorenz MW -1 297252 Town of Gilcrest 16 - 7.75 4/22/2015 NE NW 27 4 N 66 W Lorenz MW -2 297254 Town of Gilcrest 16 - 5.67 4/22/2015 NE NW 27 4 N 66 W Lorenz MW -3 297253 Town of Gilcrest 16.5 - 6.17 4/22/2015 SE NW 27 4 N 66 W State Monitoring Wells 108-1 19468-R Nelson Hans 66 550 12 5/6/1951 SW SW 27 4 N 66 W 109-3 10987-R Wiedman Terry 97 800 32 11/1/1968 SE SW 29 4 N 66 W LSP-043 11324-R Kaveny A J Sr 102 1000 22 7/1/1954 NW SW 22 4 N 66 W LSP-102 246339--A J Oliver Lorenz 45 10 20 1/7/2004 SE NE 27 4 N 66 W Greiman 11224-R Greiman Grant 56 600 9 8/1/1943 SE SW 27 4 N 66 W Lorenz 12938-R J Oliver Lorenz 34 450 8 7/1/1938 NW NE 27 4 N 66 W Nearby Wells West Well 1 630-R Nelson Thyra 90 800 35 5/1/1934 NE NW 28 4 N 66 W West Well 2 19957-R Western Equipment & Truck, Inc 75 1500 30 6/1/1917 NE NW 28 4 N 66 W 12939-R J Oliver Lorenz 92 2500 - 7/1/1938 NE NW 27 4 N 66 W 12791 -R -R Benman Scott & Wendy 74 800 45 7/9/1994 SW SW 28 4 N 66 W 953 -R -R Wiedman Terry 80 1200 39 4/4/1997 NW NW 28 4 N 66 W 6132-R Nelson Thyra 101 700 32 8/18/1958 SW SW 28 4 N 66 W 4838-F Hunt David & Kayleen 98 2000 18 5/12/1964 NE SW 28 4 N 66 W 14969 -R -R Weld County Rcorg School District 80 1200 25 9/3/1973 SE SE 21 4 N 66 W 10943 -F -R Scaefer Carl & Venice 94 800 21 3/20/1967 NW NW 27 4 N 66 W Notes: Depth, pumping rate and static water levels from Division of Water Resources well permit files. BBA +:ult:.ints BI5HOP'BROOOEN ASSOCIATES, INC. 8/29/2016 The depth to groundwater maps were used to identify and confirm those areas within the Town where water levels need to be lowered and to quantify the amount the water levels need to be lowered beneath the Town to achieve target water level depths. Utilizing the depth to groundwater maps and the Town's input regarding required water levels within Town, target depths for lowering the groundwater table were established, as discussed in more detail below. HISTORICAL LOW GROUNDWATER CONDITIONS Historical (1950 to 1980) groundwater levels beneath Town are reported to be 13 to 35 feet below ground surface, based upon well construction reports. Regular water level measurements begin in August 2014 for the three wells located within the wastewater treatment plant. However, regular water level measurements were not recorded in a majority of the Town's wells until April 2015. Historical pre -2015 reported groundwater level measurements for Town wells are summarized above in Table 2.1. The nearest well with a long-term continuous water level record (LSP-102) does not indicate substantial long-term water level change (see Appendix A). However, a well located less than 1,000 feet north of the wastewater treatment plant (LSP-43) has continuous water level data from 1956 through 1976 and 2013 through present (see Appendix A). That well shows an approximately 10 -foot water level rise, which is consistent with anecdotal reports from the Town. RECENT HIGH GROUNDWATER CONDITIONS A recent depth to groundwater map was prepared for the Town based upon April 2016 water level data from the Town, CSU, Tetra Tech, CDWR and BBA's field visit. April 2016 was chosen for depth to water mapping because the greatest number of water level measurements were available, including recent measurements toward the west of Town collected as part of this study. To prepare the April 2016 depth to water level map, groundwater elevations were contoured and subtracted from land surface elevations within Town. April 2016 water levels are approximately 3.5 feet deeper than the peak depth to water measured near the wastewater treatment plant during September 2014. The groundwater table was mapped at a 1 -foot contour interval, as shown in Figure 2.2. The groundwater table beneath the Town shows groundwater flow direction from the southeast on the east side of the Town and from south-southwest through Town. The USGS 10 -meter ground surface digital elevation model (DEM) was verified based upon surveyed elevation of the points within the Town, shown in Figure 2.3. The groundwater elevations from Figure 2.2 and ground surface elevations from Figure 2.3 were converted to a 15 -meter grid spacing to determine April 2016 depth to groundwater, shown in Figure 2.4. April 2016 depth to groundwater mapping shows extremely shallow groundwater five to ten feet beneath ground surface generally isolated to areas east of Birch Street and immediately north of Liberty Park (baseball field). 6 R66W watcr t•ii»ultanis 8;isi.,r•dtc,rrrNAssucltr[c INC 303.XU6.R952 I www.hhawatcr.cnm 4755:1 ' 1,300 1 I 1 Feet FIGURE 2.3 Town of Gilcrest Ground Surface Elevation Date: 8/25/2016 I Job No. 1606.00 "4769 a f Citt Legend • Survey Points Relied Upon 1 Ft. Contours (From 10m DEM, USGS) Town Boundary Data Source MSS. CDOT, USGS, BLM sr4780 FIGURE 2.4 Town of Gilcrest April 2016 Depth to Ground Water, Target Ground Water Depths and Dewatering Well Locations DEPTH TO GROUNDWATER TARGETS Depth to groundwater targets were developed based upon input from the Town for protection of critical infrastructure, shown in Figure 2.4. A depth to groundwater target of 18 feet was chosen for areas of the Town south of County Road 42 and east of Birch Street based upon a 12 -foot depth of wastewater basins at the Town's wastewater treatment plant, depth of sewer lines and existence of basements in the historically developed portion of Town. The Town has two wastewater pump stations, one located at 12th Street and Ash Street and a second located at 8th Street and Elm Street identified in Figure 2.4. A depth to groundwater target of 25 feet was chosen at these locations to protect pump station infrastructure and minimize I&I. For all other areas of Town, a 15 -foot depth to water target was chosen to prevent I&I to existing and future wastewater collection facilities. The depth to groundwater targets are conservatively deep and accommodate the relatively small water level decline observed in some wells between 2014 and 2016. GROUNDWATER LEVEL DRAWDOWN TARGETS The depth to groundwater targets were subtracted from the April 2016 depth to groundwater mapping to determine the amount of groundwater level drawdown required throughout the Town, shown in Figure 2.5. The greatest drawdown targets are at the Town's two wastewater pump stations and in the northeast portion of Town near the wastewater treatment facility. 10 P SECTION 3 - GROUNDWATER RECHARGE EXISTING SOURCES OF GROUNDWATER RECHARGE The purpose of this task was to identify sources of groundwater recharge that may most directly impact groundwater levels beneath the Town. The locations of recharge ponds, irrigation ditches and irrigated lands located near the Town were inventoried, as shown in Figure 3.1. We reviewed the DWR database and water rights decrees to identify the proposed location of additional structures and future potential infiltration (recharge) facilities and recharge rates for all structures. A summary of existing and proposed groundwater recharge facilities is presented in Table 3.1, including recharge facility location, historical recharge amount and maximum recharge rate. Recharge operations at the GMS Hunt, PVIC Hunt, Hunt W and Hunt SW recharge facilities are located immediately up -gradient from the Town and are likely to have the greatest impact on groundwater conditions. However, the historical amount of recharge at these facilities has been relatively small (25.1 to 162.1 acre-foot per year [af/yr]), compared to calculated groundwater underflow and the estimated rates necessary for dewatering described in later sections of this report. Although it is desirable to minimize recharge operations at these sites, they are not the sole cause for shallow groundwater conditions at the Town. The Evans No. 2 Ditch is located southeast of Town and previous groundwater modeling simulations have indicated that up to 5,614 af/yr of seepage from this ditch is a substantial source of groundwater flow beneath the Town. Anecdotal reports from irrigators that use the Evans No. 2 Ditch indicate that modeled ditch seepage may be overstated. The Evans No. 2 Ditch directly up -gradient from the Town can be used for recharge operations, (see decree in Case No. 05CW331, Water Division 1). However, irrigators report that this up gradient reach is not currently used for recharge. 12 R66W z N R,s„o. Rauonr Weideman 2012: 3.6 AF/Yr 2013: 82.5 AF/Yr 2015: 149.5 AF/Yr 1 , BBA .c.ii wirer . on'ulr anr, 0 A1SUi7ATfa 1144CI lot 5106 K') 2 I www hhnwaicr corn K - V'Frank a 2012: 13.9 AF/Yr 2013: 122:9 AF/Yr 2015: 212.6 AF/Yr LV 1 J. JL.L hl / 1 f A&W __ 1 _ _r 2014: 56.5 AF/Yr 2012: 18.9 AF/Yr 2015 28.1 AF/Yr 2013: 297.9 AF/Yre Hunt 2 2015: 607.4 AF/Yr union ditch 2013: 4.9 AF/Yr 2015: 188.3 AF/Yr .,7 western, mut wei ditch r Buderus Schmidt 1 ` 2012:,9 4-AF/Yr 2013i/7'1/.3 A F /Y r --- 1 2014: 61.7 AF/Yr 2015: 51.7 AF/Yr A&W East Farr 2012: 539.3 AF/Yr. 2013: 1,379.5 AF/Yr 2014: 682.9 AF/Yr 2015: 429.6 AfF/Yr• I.f .Bella.Farms.West, Hendrickson Bella Farms East 1 1 1 l 1 Miles ter-`tr , ) I 2 FIGURE 3.1 Town of Gilcrest Recharge Facilities in Vicinity of Town Date 9/1/2016 I Job No. 1606.00 Sec. 02 Legend Recharge Facilities Active with diversion records Active no diversion records Historical with diversion records Inactive no diversion records Non-existent no diversion records Data Source B&C. CDSS COOT USGS BLM �J Town Boundary .1 Area of Interest Irrigated Area - 2010 Schmidt 3 -- 2014: 46.7 AF/Yr 2015: 44.8 AF/Yr c DRAFT Table 3.1 Town of Gilcrest Active Recharge Facilities in Vicinity of Town Facility Recharge Deliveries (af/yr) Maximum Delivery Rate (cfs) 2012 I 2013 I 2014 I 2015 Farmer's Independent Ditch Weidman 3.6 82.5 0.0 149.5 2.4 V Frank 13.9 122.9 0.0 212.6 9.9 A & W 18.9 297.9 0.0 607.4 54.7 A & W Central Farr - 539.3 - 1379.5 - 682.9 - 429.6 16.6 R Ewing 0.0 31.6 0.0 0.0 2.2 D Ewing - - - - Subtotal 575.7 1914.4 682.9 1399.1 Evans No. 2 Ditch Hunt SW 0.0 0.0 94.1 0.0 1.3 Hunt W 0.0 52.2 56.5 28.1 0.9 PVIC Hunt 25.1 16.1 0.0 0.0 1.1 GMS Hunt 0.0 34.7 11.5 51.0 3.5 Schmidt 1 9.4 71.3 61.7 51.7 1.0 Schmidt 2 7.1 28.9 0.0 66.6 1.2 Schmidt 3 0.0 0.0 46.7 44.8 1.1 Subtotal 41.6 203.0 270.5 242.1 Western Mutual Ditch Haren 0.0 1260.5 5578.3 4279.4 32.8 Schafer 0.0 4.9 0.0 188.3 1.3 Subtotal 0.0 1265.4 5578.3 4467.6 Other Buderus 3 - Hendrickson J Total Recharge 617.3 3382.8 6531.8 6108,9 Notes: 1. All recharge structures identified as "active" in CDSS records. 2. Recharge calculated utilizing daily diversion records from CDSS. 3. Structures are classified as active with diversion records in CDSS, but have no diversion records. � _ BB 8/9/2016 BISHOP-BROGDFN ASSOC/Ares INC SECTION 4 - DEWATERING SYSTEMS EXISTING DEWATERING STRUCTURES An inventory was made of the existing wells and stormwater ponds that could potentially be used for dewatering. The Town's GMP, Main Street and Elm Street (M+E), Town Hall (TH) and 5`h Street wells were identified as potential dewatering wells. These wells have estimated historical pumping capacities of approximately 300 gpm to 800 gpm. Details about these and other wells in Town are presented in Table 4.1. The GMP and M+E wells located at ideal dewatering sites, but are approximately 20 and 46 years old, respectively, and would need to be replaced to achieve maximum well yields. NEW DEWATERING STRUCTURES Additional potential dewatering well sites were identified based upon current and expected future land use within Town. Figure 4.1 presents a total of 11 potential well sites that were considered for dewatering. Of those sites, only the WWTP site was included in the conceptual dewatering alternatives. Table 4.1 — Summary of Town Wells Name ' Permit No. Year Constructed ReportedRat Status 5th St. 12390-R 1945 300 Active M+E 13119 -F -R 1970 800 Operational, Inactive TH 13118-F 1956 800* Not Operational GMP 47041-F 1996 700 Active Notes: Rates and statuses reported by Town of Gilcrest. *Rate reported on Permit No. 13118. Rates and statuses reported by Town of Gilcrest 600 -FOOT SPACING Water supply wells located within 600 -feet of each potential dewatering well sites were identified based upon records available from the Division of Water Resources and communications with Town staff. Figure 4.1 identifies water supply wells located within 600 -feet ofpotential dewatering well sites and information regarding those wells is summarized in Table 4.2. Pursuant to C.R.S. 37-90-137(2)(b) dewateringrwells must be located more than 600 -feet from any water supply well unless a waiver has been obtained from the well owner. 15 PRACTICAL PUMPING RATES The maximum practical pumping rate for newly constructed dewatering wells was calculated based upon a range of assumed aquifer characteristics and two-thirds well drawdown. Table 4.3 summarizes estimated maximum pumping rates for various length pumping periods and aquifer characteristics discussed later in this report. Based upon a 1 -year pumping period, the range of expected maximum well pumping rates is 1,849 gpm to more than 2,500 gpm. Table 4.2 — Wells Within 600 Feet of Proposed Dewaterina Wells Permit No. Owner Depth (ft) Pumping Rate (gpm) Proposed Well Within 600 feet 16163 -F -R Keiser Henry 98 1000 South Nelson 159311--A Keiser Henry 95 15 South Nelson 14968-R Cogburn Earl 73 1200 Vine + 11th 14967-R Cogburn Earl 80 1000 SW 4838-F Hunt David W 98 2000 SW 630-R Nelson Thyra 90 800 West Basin 19957-R Western Equipment 70 1500 West Basin 14969 -R -R Weld School District 80 1200 North School 432-WB Mcleod Royal 70 GMP 47041-F Town of Gilrest 91 700 GMP 13119 -F -R Town of Gilcrest 95 800 M+E Notes: Depth and pumping rate from Division of Water Resources well permit files. Table 4.3 — Summary of Estimated Maximum Pumping Rates Transpdift) ity (gpd/ft) Storage Radius (ft) Saturated Thickness (ft) Maximum Rate m / Pumping Period (days) (gpm)p g 1 7 30 180 365 1826 100,000 0.2 1 90 > 2500 > 2500 2277 2039 1958 1796 300,000 0.2 1 90 > 2500 > 2500 > 2500 > 2500 > 2500 > 2500 Notes: Maximum drawdown is 2/3 of saturated thickness. Jacob equation is used for maximum pumping rate calculations. Transmissivity is adjusted for declining saturated thickness. 17 SECTION 5 - INITIAL DEWATERING RATE ESTIMATES Quantitative evaluation of groundwater flow conditions was evaluated using three methods: (1) groundwater underflow calculation based upon groundwater mapping prepared in the 2014 CGS Report and 2015 CGS Report, (2) calculations based upon the water budget mass balance presented in the 2015 Brown and Caldwell Report and (3) superposition well drawdown analysis. These analytical methods allowed the study team to estimate the magnitude of dewatering rates required to achieve the Town's target depths and identify optimal dewatering sites. Estimated dewatering rates were refined through groundwater model analysis, summarized in Section 6. Aquifer characteristics were evaluated to support the dewatering rate estimates. The results of the analyses are presented in Tables 5.1 and 5.2, and discussed further below. AQUIFER CHARACTERISTICS Aquifer characteristics of saturated thickness, hydraulic conductivity and specific yield strongly influence groundwater flow and dewatering rates required to achieve the Town's depth to groundwater targets. Long-term aquifer pumping tests are the best source for data regarding aquifer characteristics, however there are limited aquifer pumping test data available in the immediate vicinity of the Town. Based upon reported depth to bedrock and mapped groundwater levels in the vicinity of the Town, the average aquifer saturated thickness ranges from approximately 75 to 95 feet. Aquifer hydraulic conductivity was estimated to range from 400 to 800 ft/d in the vicinity of the Town based upon the 2014 CGS Report. The nearest controlled long-term aquifer pumping was completed 3 miles north of Town near the intersection of County Road 35 and U.S. Highway 85 in 1957, identified in Figure 5.1. That test is documented in Circular 11 (Pumping Test in Colorado, USGS, 1965) as B4-66-11 adc, and shows a hydraulic conductivity of 1,270 ft/d, a transmissivity of 370,000 gpd/ft and storage coefficient of 0.03. During September 17 through November 1, 2015 water levels and pumping rates monitored near -continuous operation of the Lorenz well. Analysis of water level data from observation wells located near the Lorenz well indicate a hydraulic conductivity of approximately 150 ft/d and a transmissivity of approximately 100,000 gpd/ft. Based upon published values and analysis of well pumping test data, a transmissivity (product of hydraulic conductivity and saturated thickness) ranging from 100,000 to 300,000 gpd/ft was used for groundwater analyses for the Town. That range is based upon an average saturated thickness of approximately 90 feet and a hydraulic conductivity ranging from 150 to 470 ft/d. Specific yield was assumed to be 20%, which is the same value used in regional groundwater models and in support of numerous water court decrees. 18 Table 5.1 — Underflow Calculation Un a (cf) Rate (cfs) Underflow Rate Per foot of Saturated Thickness (cfslft) Hydraulic Conductivity (ft/d) rated Thickness 4) ` Transmissivity (OPdlft) Hydraulic .. Gradient ) 2.55 0.03 149 90 100,000 2.6E-03 3.37 0.04 149 90 100,000 3.4E-03 7.65 0.08 446 90 300,000 2.6E-03 10.10 0.11 446 90 300,000 3.4E-03 Notes: Hydraulic gradient from Appendix C, 2013 Time -Series Historic Groundwater Elevation Contour Map, CGS Report. Transmissivity from CGS Report and Lorenz monitoring well calculations. Town width is 6,375 feet. Saturated thickness estimated at 90 feet based on nearby well depths and water levels. Underflow rate = transmissivity * hydraulic gradient ` town width. Table 5.2 — Summary of Theis Equation Superposition Model Results Location Target Drawdown (ft) T o 100,000 gpdift T = .300,000 g lft s Rate (gym) Simulated Drawdown (ft) Rate (gpm) Simulated Drawda Proposed Wells WWTP 9.4 785 27.1 2200 25.2 GMP / Pump St. 1 15.3 1540 45.5 2200 25.9 West Basin 4.0 7.5 8.8 RE1 10.6 10.6 695 14.8 Vine + 11th 8.3 13.2 12.5 Baseball Field 0.5 8.2 9.1 M+E 5.8 1022 29.5 2200 23.8 South Nelson 5.4 7.8 8.7 SW 0.0 5.2 6.6 Observation Points SW -Town Boundary 0.0 2.9 4.6 NW -Town Boundary 0.0 5.4 -, 7.0 SE -Town Boundary 1.5 4.5 6.0 E/C 10.4 10.4 10.5 Pump Station 2 12.6 12.8 12.6 South Birch 4.1 6.2 7.4 North Birch 1.3 9.3 10.4 Total (gpm): 3307 Total (cfs): 7.4 7295 16.3 Note: Target drawdown calculated as the target water level at location less April 2015 water level. 19 Saturated Thickness Saturated Thickness (ft.) <25 25 - 35 35-45 45-55 55 - 65 65 • 75 MI 75-85 1 I 85 - 95 95 105 Transmissivity Computed Transmissivity (gpd'fti 50,000 50,000 - 150,000 150.000 - 200,000 200.000 - 250.000 250,000 - 300,000 z, 300.000 ►P SMITH 20,000 DSS02MLK AP SMIT-I 1111 I yr.d - 1 B4-66-11 adc Lorenz (12939=R) 100,000 Hydraulic Conductivity Distribution tt/day 200 2C0 -40U r' k 400 - 600 !. 600 -800 AP WILSON gpd/ft AP.SMITH,1 t1 695 (N/A) 1121 (2f0 @:0m) B4-66-11 adc AP.AWILSON 91 1,192 (N/A) AP SMITE 11 ILCRES Lorenz (12939-R) 150 ft/day (N/A) Figure 5.1 Town of Gilcrest Aquifer Characteristics Date: 8/25/2016 I Job No. 0403.25 Legend U Well Location Town Boundary Base map from 2014 CGS Report 0 N w MIN IMO 2 Miles BBA �l water consultant s R l siins' R itminIN A, Ni,4 14 1'FS. ?NC' 303.806.8952 I www.bbawatcr.com Appendix C PRINCIPIA November 22"d, 2019 Gilcrest Groundwater Flow Model Hypothetical Pumping Wells & Drains Hypothetical Pumping Wells Extracting from the October 2016 Dewatering Improvements Study' by JVA, Inc and Bishop-Brogden Associates, Inc. for the Town of Gilcrest, Colorado, three hypothetical pumping wells were selected to evaluate the effects of pumping. Three wells were simulated in the groundwater flow model to pump at varying rates for three years of operations to evaluate the effects of pumping on water level elevations in the immediate vicinity of the Town of Gilcrest. The locations of these three pumping wells were selected to match the locations of the Town of Gilcrest Waste Water Treatment Plant (WWTP), Pump Station 1 (PS1) and Pump Station 2 (PS2), as depicted in Figure 2.4 of the Dewatering Improvement Study report. The three hypothetical pumping wells and monitor wells in the vicinity are depicted in Figure 1. Pumoine Rates of the three wells: Well Pumping Rate (gpm) Pumping Rate (cfs) WWTP 450 -1.0 PS 1 2500 -5.6 PS2 1400 —3.1 The hypothetical pumping rates for these three wells are shown in Figure 2. These three wells were each simulated to pump at their varying rates for a period of 36 months. Hypothetical Drains In addition to simulating pumping from three wells, a set of hypothetical drains were placed along the west and south-east perimeter of the Town of Gilcrest. The locations of the modeled drain cells are depicted in Figure 3. Two separate groundwater model simulations were undertaken with these perimeter drains, with the bottom drain elevations set at 2' and 5' below the starting water table. The locations of the pumping wells and drains, in relation to the model transmissivity, are depicted in Figure 4. PRINCIPIA MATHEMATICA INC. 445 UNION BLVD, SUITE 230 LAKEWOOD, COLORADO 80228 WEB www.prinmath.com TELEPHONE (303) 716-3573 FAX (303) 716-3575 Model Simulation Results: Pumping & Drains The predicted head changes from the pumping simulations are depicted in Figure 5, at 6 month intervals. After 36 months of pumping, the predicted drawdown at PS1 is —25', at PS2 is —20', and at WWTP is —19'. Within the 15' Target Groundwater Zone, the predicted drawdown after 36 months ranges from —17' to —25' at PS1. Within the 18' Target Groundwater Zone, the predicted drawdown after 36 months ranges from —8' to —20' at PS2. The predicted change in water levels from the two separate drain simulations (2' and 5') are depicted in Figures 6 and 7, at 6 month intervals. After 36 months of drain operations (2' drain elevation), drawdown in the 15' Target Groundwater Zone is —2', while in the 18' Target Groundwater Zone, drawdown ranges from —1' to —1.5'. For the simulation with a drain elevation of 5', drawdown in the 15' Target Zone is —5', while in the 18' Target Zone, drawdown ranges from —2.5' to —4.5'. The model predicted water level changes for the pumping and drain simulations, at monitor wells in the vicinity of the Town of Gilcrest are shown in Figures 8-29. The table below provides a tabulation of the predicted drawdown at each of the monitor wells, after 36 months of pumping/drain operations. Water Budgets: Monthly water budget results for the well pumping simulation are depicted in Figure 30. Well pumping was approximately 600 Acre-Feet/Month. Inflow from storage was approximately 600 Acre-Feet/Month initially, with storage inflow decreasing to approximately 275 Acre-Feet/Month after 36 months. Inflow from (or depletion to) the South Platte River was initially 0 Acre-Feet/Month, with inflow increasing to approximately 215 Acre-Feet/Month after 36 months. Initial constant head inflow (south and north ends of model domain) was initially 0 Acre-Feet/Month, with inflow approximately 110 Acre-Feet/Month after 36 months. Monthly water budget results for the drain simulation with a bottom elevation of -2' are shown in Figure 31. Outflow from the aquifer to the drains was approximately 245 Acre-Feet/Month initially, with outflow decreasing to approximately 60 Acre-Feet/Month after 36 months. Initial inflow from storage was approximately 245 Acre-Feet/Month, decreasing to 20 Acre-Feet/Month after 36 months. Inflow from the South Platte River was initially 0 Acre-Feet/Month, increasing to approximately 25 Acre-Feet/Month after 36 months. Constant head inflow from the southern and northern boundaries was initially 0 Acre-Feet/Month, increasing to approximately 15 Acre-Feet/Month after 36 months. Monthly water budget results for the drain simulation with a bottom elevation of 5' are shown in Figure 32. Outflow from the aquifer to the drains was approximately 615 Acre-Feet/Month initially, with outflow decreasing to approximately 145 Acre-Feet/Month after 36 months. Initial inflow from storage was approximately 615 Acre-Feet/Month, decreasing to 45 Acre-Feet/Month after 36 months. Inflow from the South Platte River was initially 0 Acre-Feet/Month, increasing to approximately 65 Acre-Feet/Month after 36 months. Constant head inflow was initially 0 Acre-Feet/Month, increasing to approximately 35 Acre-Feet/Month after 36 months. JVA, Inc. and Bishop-Brogden Associates, Inc, Dewatering Improvement Study, October 2016, 101 p. 2 Predicted Drawdown (After 36 Months) Well Pumping Simulation Drain Simulation (-2') Drain Simulation (-5') MW1: Lorenz West 9.2' 1.0' 2.6' MW2: Lorenz South 13.4' 1.5' 3.6' MW3: Lorenz North 14.7' 1.5' 3.8' MW4: Fritzler East 5.9' 0.6' 1.6' MW5: Fritzler Central 7.6' 0.8' 2.1' MW6: Fritzler West 9.1' 1.0' 2.4' MW7: Weideman 11.6' 1.3' 3.3' MW8: Ulrich West 4.6' 0.5' 1.4' MW9: Ulrich East 3.5' 0.4' 1.1' Nelson 13.1' 1.5' 3.8' Main & Elm 17.3' 1.9' 4.8' 5th Street 14.8' 1.8' 4.4' Town Hall 18.2' 2.0' 5.0' , Pumping Well PS1 25.0' 1.8' 4.6' Pumping Well WWTP 18.5' 1.7' 4.4' WWTP South 19.2' 1.8' 4.5' WWTP East 18.7' 1.8' 4.5' RE1 16.7' 1.9' 4.8' Lorenzo 12938-R 9.5' 1.0' 2.6' CDA WL-M-003A 8.3' 1.0' 2.6' Greiman 11224-R 6.3' 0.75' 1.9' Pumping Well PS2 19.8' 1.9' 4.8' 3 Hypothetical Pumping Wells & Monitor Wells Pumping & Monitor Wells 1698000 1700000 I I 15' Target Groundwater Zone 18' Target Groundwater Zone I Hypothetical Pumpiig Well Existing Monitor Wells 0 0 0 CO M to K Weideman O 0 M 40 v 0 0 ao N t0 0 0 0 to N CO Nclson SPDSS Alluvial Groundwater Model (UTM83-N13 Survey Feet) 1702000 1704000 Mary Sr: Elm 1698000 1700000 1702000 1704000 (UTM83-N13 Survey Feet) r tzlei Wesi'. WWTP Wet PS2"•'S4.4t ow rl jet CDA W L -M-00 3A Figure 1 WWTP East 1706000 n zor Central GREIMAN 11224-R 1706000 1708000 orenzo 12938-R Lorer West lair ch est 1-'08000 rich East 1710000 17100 14636000 O O 4 M t0 14.630000 0 0 CO N t0 0 0 0 to N O O O 0 O O o E o O_ O ii � N E O O Q_ Lf) O O 0 O 0 LU O Hypothetical Pumping Rates SPDSS Alluvial Groundwater Model 4.50 WWTP T 2500 PS1 1 } 400 Figure 2 4350 P52 Tota Hypothetica Drains (2' or 5') I 0 0 0 tfl_ M UP I - w S m L- 0 y0 Zit) - (OW M r- Z M CO I- o- n 0 0 to V O 0 ,O W N to 1698000 Hypothetical Drains & Monitor Wells 1700000 15' Target Groundwater Zone 18' Target Groundwater Zone Hypothetical Drains Existing Monitor Wells 1698000 1700000 SPDSS Alluvial Groundwater Mod I' i (UTM83-N13 Survey Feet) 1702000 1704000 L I ritzier West I I 1702000 1704000 (UTM83-N13 Survey Feet) Figure 3 1706000 GREIMAN 11224-R 1706000 1708000 orenro 12938-R 1708000 1710000 14636000 O 0 O d re) tD d 0 CO O N to Model Transmissivity: Hypothetical Pumping Wells & Drains 14660000 O O 0 O u) t0 14620000 O O O O r cO 1680000 Transmissivity, Wells & Drains SPDSS Alluvial Groundwater Model 1690000 1680000 1690000 1700000 1710000 (UTM83-N13 Survey Feet) 15' Target Groundwater Zone 18' Target Groundwater Zone Hypothetical Drains Hypothetical Pumping Wells (UTM83-N13 Survey Feet) 1700000 1710000 1720000 1730000 Figure 4 1720000 1730000 14660000 14650000 O^.. O 47 O OV- CA >- tC tr V: 6%1M, I M, O0C 0 � O M tO 0 8 0 t4 CO It r O O 0 O to get Appendix D Report to the Colorado Legislature HB12-1278 Study of the South Platte River Alluvial Aquifer December 31,E 201 GROUNDWATER PUMPING Key Points The SB06-193 study conducted by the Colorado Water Conservation Board (CWCB) estimated 10 MAF of water is stored in the S. Platte alluvial aquifer. Prior to 2003, approximately 8,200 high capacity wells pumped on average nearly 500,000 AF/yr from the alluvial aquifer. There are now approximately 6,500 highcapacity wells in the alluvial aquifer, and total annual groundwater pumping in the basin is now closer to 450,000 AF/yr, with agricultural pumping estimated in the 400,000 AF/yr range. In 2005, 60% of the 830,000 irrigated acres in the basin were watered solely with surface water, 18% solely with groundwater, and 22% with a mix of surface and groundwater. Most of the irrigation wells in adjudicated augmentation plans now have full or near full allocations in most years, however, the Central Colorado Water Conservancy District has approximately 1,200 wells in the WAS and GMS plans that are on a restricted quota and not able to pump 100% of full crop ET. The greatest groundwater pumping occurs in Water District 1, which correlates with the large amount of acreage served only by groundwater. The greatest percentage reduction in pumping has occurred in Water District 2 as Central WAS and GMS and other augmentation plans work to develop reliable augmentation supplies. Water District 64 has the most recharge and surface augmentation sources due to their downstream position in the basin. Pumping amounts have returned to previous levels in District 64. Groundwater pumping has shown a rebound in Water Districts 2, 1, and 64 since 2009 as additional augmentation supplies have been acquired and adjudicated. Groundwater pumping and consumptive use estimates were developed for the HB1278 study by the Wilson Water Group in collaboration with Leonard Rice Engineers. The well metering rules enacted in 2013 will enhance future pumping analyses. Description of the South Platte Alluvial Aquifer The S. Platte alluvial aquifer consists primarily of silt, sand, and gravel deposits of alluvial and aeolian origin that cover an area of over 4,000 square miles. Drilling logs indicate the deposits near the base of the alluvium are coarsest and become finer towards the surface, with considerable heterogeneity in the aquifer materials, particularly with respect to clay and silt. Clay layers are common throughout the basin, both laterally and vertically, and although clay layers may not be laterally continuous over great distances, they can affect pathways of groundwater movement. In addition, the aquifer grades from coarsest material in the west to finer material in the east. The ancient S. Platte River and its tributaries, swollen with snowmelt at the end of the last ice age (Pleistocene), left extensive alluvial deposits ranging in width from two to six miles wide and up to 200 feet deep in the main river channel. The flood plain of the S. Platte River east 41 of the Front Range averages about a mile in width and has an irregular surface that consists of swamps, oxbow lakes, abandoned meander scars, and low, indistinct terraces (Smith et al., 1964). The overall surface drainage in the region is toward the northeast. Surface topography consists of many terraces and subtle changes in topographic relief that can make differences in water table depth over short horizontal distances. The major perennial tributaries of the S. Platte River in the project area are Clear Creek, Big and Little Dry Creeks, St. Vrain Creek, the Big Thompson River, Cache la Poudre River, Lone Tree Creek, and Crow Creek. Several intermittent streams also enter the river below Kersey, including Kiowa, Bijou, Badger, Wildcat, Beaver, Pawnee and Cedar Creeks. The alluvial aquifer is in hydraulic communication with the surface water system throughout the basin, and the extensive development of irrigation, reservoirs, transbasin diversions, and wells has resulted in gaining conditions for the majority of the river since application of irrigation water results in deep percolation, and resulting return flows to the river. The maximum thickness of the alluvial deposits increases in a downstream direction on the mainstem with saturated thickness of 20 to 40 feet in the upstream region near Denver to more than 200 feet near Julesburg (Map 4). Well depths in the lower S. Platte River basin alluvium average about 75 feet below ground surface. The hydraulic characteristics of the aquifer are such that high -capacity irrigation wells may yield 1,200 to 2,000 gallons per minute. Hydraulic conductivity is the main physical parameter that governs the rate of groundwater flow, varying considerably within relatively small areas in the alluvial aquifer. Hydraulic conductivity (K) values in the S. Platte alluvial aquifer range from approximately 20 to 2,000 feet per day (with a median value near 500 ft/day) depending on the materials present. Infiltration from precipitation, irrigation, canal seepage, and pond seepage recharge the alluvial aquifers whereas groundwater tends to discharge to the main channel of the river. Groundwater discharge to the river channel creates baseflow for the river. All groundwater in Water Division 1 that is not either Designated groundwater or Denver Basin groundwater is presumed to be tributary groundwater, in direct hydraulic connection to the surface stream system. However, there are a number of water right decrees in Water Division 1, generally entered from 1910 to 1970 that specifically declare the groundwater to be nontributary. The almost 500 so-called Coffin Wells in Water District 1 and 3 were decreed as non -tributary by Judge Coffin in 1953, although today we know they are in the alluvial aquifer and are indeed tributary to the S. Platte River. 42 GREELEY A DENVER Miles 0 10 20 40 FQR'T MORGAN ULESBLIR STERL4NG High Capacity Irrigation Wells (>50gpm) Division 1 Water Districts District 1 District 2 District 64 South Platte River Cache la Poudre River South Platte River Alluvial Extent Datum/Projection NAD83/UTM Zone 13N Data Source: Colorado Division of Water Resources I i►„«;f. Map 3. High Capacity Wells in the S. Platte Alluvial Aquifer. Data Source: CO DWR HydroBase Version 20130710 43 Base from U S Geologrca Survey digital data. 2009.1 100.000 lambert Conformal Conic prolectIon (Colorado State Plane Central) Standard parallels 38 27' N and 37' 45 N. central meridian 105 0(1W Map area terling PNll 1) EXPLANATION Water division 1 S. Plane Aquifer Water district 1 Water district 2 Water district 64 S. Plane Aquifer depth, in ft High : 300 Low : 10 0 10 10 MILES Ill , , t 0 10 20 KILOMETERS USGS science for a changing world Map 4. Aquifer Depths Across the S. Platte Alluvial Aquifer Showing Greatest Depths at the Channel Center to the East and Central Regions Near Fort Morgan and Along Lower Sections of the Lost Creek Tributary. 44 800000 700000 800000 500000 400000 300000 200000 100000 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Figure 1. Estimated Groundwater Pumping for Irrigation from the S. Platte Alluvial Aquifer, 1950 — 2006. Source: Historic Crop Consumptive Use Analysis South Platte Decision Support System (Final Report), p.44, by Leonard Rice Engineers, Inc., 2010, Denver, CO. A number of studies have examined the alluvial aquifer of the S. Platte River and its tributaries. Stratigraphy of the alluvial deposits was originally described by Hunt (1954) and Scott (1960) and later by Scott (1963a). Several workers developed maps of the S. Platte alluvial aquifer extent, thickness, and depth to water beginning in the 1950s (Bjorklund and Brown, 1957; Smith and others, 1964; Duke and Longenbaugh, 1966; Nelson and others, 1967; Hurr, Schneider, and others, 1972a, 1972b, 1972c; Hun and others, 1975; Konikow, 1975; Nadler and Schumm, 1981; Robson, 1996; and Robson, Arnold, and Heiny, 2000a, 2000b; Robson, Heiny, and Arnold, 2000a, 2000b). The South Platte Decision Support System (SPDSS) compiled selected maps of these features into Geographic Information System (GIS) data sets (CWCB, 2006b). Robson (1989) described the interconnection between bedrock and alluvial aquifers in the study area. The SB06-193 study conducted by the CWCB revealed that there is an estimated 10 MAF of stored water in the S. Platte alluvial aquifer; 14 MAF if the designated basins are included. The study also estimated there is some 7 MAF of unsaturated alluvium that some fraction of which would be available for aquifer storage (Table 1). 45 Table 1. Estimated Storage Volumes in the S. Platte River Basin Alluvium'. Mainstem Unsaturated Volumes. Saturated Volumes° Denver Metro Metro to Greeley Greeley to Ft. Morgan Ft. Morgan Area Balzac to State Line Total 353,000 169,000 94,000 968,000 890,000 2,474,000 479,000 920,000 1,143, 000 2,055,000 4,058,000 8,655,000 Tributaries Cache la Poudre River Upper Beebe/Box Elder Lower Beebe/Box Elder Badger/Beaver Creek Total 291,000 268,000 61,000 311,000 931,000 859,000 494,000 259,000 600,000 2,212,000 Designated Basins Upper Lost Creek Lower Lost Creek Upper Kiowa Creek Lower Kiowa Creek Upper Bijou Creek Lower Bijou Creek Total 1,260,000 157,000 234,000 806,000 466,000 1,067,000 3,990,000 925,000 348,000 298,000 580,000 450,000 1,406,000 4,007,000 Total Volume Total Volume minus Designated Basins 7,395,000 14,874,000 3,405,000 10,867,000 Source: Based on data from the SPDSS and SB06-193 studies I. Volumes rounded to the nearest 1,000 AF. 2. Sub -Regions defined in Figure 4 of SB06-193 Study Unsaturated volumes exclude the upper 10 feet; from Table 2 of SB06-193 Study. Saturated volumes are from average water table surface to base of alluvium. 46 Map 5. Aquifer Cross -Sections at Five Locations along the S. Platte River. Source: Colorado Groundwater Atlas, Colorado Geological Survey. Groundwater Use Prior to 2003, on average nearly 500,000 AF of groundwater was pumped annually in the S. Platte basin from approximately 8,200 high capacity wells (Figure 1 and Map 3). Agricultural pumping between the years 1950 to 2000 was calculated to average 438,000 AF/yr with municipal and industrial pumping growing to approximately 50,000 AF/yr during this same period. There are now approximately 6,500 high capacity wells in the basin and total annual groundwater pumping in the basin is now closer to 450,000 AF/yr with agricultural pumping in the 400,000 AF/yr range (Table 2). Approximately 1,000 high capacity wells were abandoned through the 2010 Abandonment List, many of these were former GASP wells and of these, many had low pumping rates and were supplemental for drought insurance. Central Colorado Water Conservancy District has approximately 1,200 wells in the WAS and GMS plans that are on a quota system and not able to pump anywhere near 100% of full crop ET (GMS quota has been in the 35% range since 2006; WAS quotas have been even less). Most of the other irrigation wells in adjudicated augmentation plans have full or near full allocations in most years. While rules now require well owners to meter and provide pumping records, it will likely be several years before we have accurate accounting of wells metering records to determine exactly how much individual wells are pumping and how much water is extracted from the various reaches of the alluvium in the basin. 47 For the purposes of augmentation plans, two methods are generally used to determine the amount of stream depletion caused by well pumping: 1. crop potential consumptive or 2. presumed depletive factor. The crop potential consumptive method involves determining the potential crop consumptive use for the land irrigated by the wells in the plan. Any available surface water is subtracted from the potential consumptive use and the remainder is assumed to be the stream depletion caused by wells. This method was commonly used prior to 2003 but is not generally used in recent augmentation plans. The second and currently most commonly used method for estimating stream depletion is the presumed depletive factor (PDF). In this method, well volume is recorded or calculated and a specified percentage of that pumping is assumed to be consumptively used by the crop depending upon irrigation method (and hence the streamflow depletive amount). In most plans, sprinkler irrigation is assumed to have an 80% PDF and surface irrigation is assumed to have a 60% PDF. Table 2. High Capacity Irrigation Well Count in Hydrobase by Water District in Division 1 Before and After Adjudication of the 2010 Abandonment List. Wells Wells Water Needing Needing District Augmentation Augmentation Before 2010 After 2010 Coffin Wells Total Wells After 2010 WD 01 2279 2092 236 2328 WD 02 1939 1613 0 1613 WD 03 800 695 211 906 WD 04 112 77 0 77 WD 05 82 48 0 48 WD 06 91 25 0 25 WD 07 156 132 0 132 WD 08 591 456 0 456 WD 09 31 26 0 26 WD 23 24 24 0 24 WD 48 0 0 0 0 WD49 4 4 0 4 WD 64 980 944 0 944 WD 65 0 0 0 0 WD 76 0 0 0 0 WD 80 13 12 0 12 Total for 7102 6148 447 6595 Div. 1 48 Appendix E EXHIBIT G — WATER INFORMATION This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.4.7 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Locate on the map (Exhibit C) tributary water courses, wells, springs, stock water ponds, reservoirs and ditches The site is 0.4 miles east of the South Platte River. Please refer to Exhibit C for locations of water courses in close proximity to the site, including wells, springs, stock water ponds, reservoirs and ditches. (b) Identify all known aquifers The site is underlain by a shallow alluvial aquifer, typical of its position upgradient of the South Platte River. (c) Show how water from dewatering operations or runoff from disturbed areas, piled material and operating surfaces will be managed to protect against pollution of either surface or groundwater both during and after the operation. Please refer to the Mining Plan Map in Exhibit C-5 of this application. Mine areas will drain internally. Uncontrolled releases of surface water in disturbed areas will not occur. Stormwater collected in the active mine area will be managed through the dewatering system. Dewatering will be accomplished by digging a sump, generally along the base of the mine slope, which will hold a floating pump. The pump will have an HDPE discharge line that will be routed to one of the comingled discharge points located at the site. The pump will be powered by a diesel generator housed in the active mine area. The Operator will apply for and receive a comingled stormwater and process water discharge permit prior to dewatering at the site. (d) - Estimate project water requirements including flow rates and annual volumes for the development, mining and reclamation phases of the project. Water needs estimated below provide for sustained production as detailed in the Mining Plan. The Operator will adjust water supplies to account for actual demand, avoid waste, and continuously comply with laws and regulations of the Division of Water Resources and any other water agency having jurisdiction over the operation. Protected Use And Consumption: Annual evaporative depletions will be the evaporation from up to 5000 feet of 4 -foot wide de -watering trench, located inside of the slurry wall. The total area of exposed water is 0.5 acres. The gross annual evaporation at the Section 20 Mine is 42 inches according to NOAA Technical Report NWS 33, Evaporation Atlas for the Contiguous 48 United States. Monthly evaporative losses are determined using percentages specified by the State Engineer's Office for locations below 6,300 feet. The nearest weather station is in Longmont where the average annual precipitation is 15.08. Effective Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G -1 precipitation, that part of historical precipitation which was consumed by native vegetation on land to be covered by water surface, is conservatively estimated to be 70 percent of the total precipitation. The annual average effective precipitation at the property is estimated to be 9.09 inches. When subtracting the effective precipitation from the gross evaporation yields, the net annual evaporation is 31.44 inches, or 2.68 acre-feet per acre. The Fresh Water Pond is approximately 10 acres and the Siltation Pond will be utilized in 10 acre stages. The approximate acreage of open water surface is 20.5 acres. The annual amount of evaporation from open water surfaces is 54.9 acre-feet. Mining Production & Operations: The Operator expects to extract approximately 2 million tons annually of aggregate material from the site. All water retained in the recovered material will be replaced pursuant to the Substitute Water Supply Plan (SWSP). The total annual amount of water retained in the gravel product from mining activities totals approximately 27.2 acre-feet. The SWSP is renewed annually and will reflect analysis of production and depletion anticipated in each year of operation. In addition, an estimated 4.0 acre-feet of water per year will be used for dust control based (approximately) on 5,900 gallons per day for 5 days a week for 10 months. Annually the total evaporative and operational losses from mining activities (open water surface evaporation, water retained in the aggregate product, dust suppression) totals 86.1 acre-feet of depletion which must be augmented. All depletions were lagged to the Saint Vrain River using the lagging factors approved by the State Engineer pursuant to on -going Substitute Water Supply (SWSP) approvals. (e) Indicate the projected amounts of the water sources to supply project water requirements Replacement Water: The Miner will obtain an approved Substitute Water Supply Plan from the State Engineers office every year, providing annually or more frequently the opportunity to review the sufficiency of water supplies. The SWSP approvals require that the applicant provide a detailed explanation of the mining operations, a quantification of all mining activities and subsequent depletions and all legally available replacement sources. (i) Affirmatively state that the Applicant has acquired or applied fora National Pollutant Discharge Elimination System permit from the Water Quality Control Division The Operator will apply for a National Pollutant Discharge Elimination System (NPDES) permit from the Water Quality Control Division of the Colorado Department of Public Health and Environment prior to discharging water from the site. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 2 Groundwater Sampling and Analysis Plan This information provided in this subsection of Exhibit G is intended to satisfy the requirements outlined in the Groundwater Monitoring and Protection Technical Bulletin dated November 19, 2019: Existing Groundwater Conditions The near surface groundwater is part of an alluvial aquifer in which permeable sand and gravel alluvium overlies relatively impermeable bedrock of either the Fox Hills Sandstone and/or the Laramie Formation. Groundwater, measured in 7 piezometers, occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the site. The prevailing groundwater flow at the site is to the north reflecting the site topography. Groundwater in the area is tributary to the South Platte River located northwest of the site. Locally the groundwater levels and flow directions are likely influenced by: ➢ The South Platte River is northwest of the site. For most of the year, the river likely acts as a drainage way maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the site under the intersection of Weld County Road 42 and Weld County Road 29. The ditch may act like a drain during the non - irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ The Farmers Independent Ditch traverses the southeast corner of the site and bisects Cell 5a and 5b. The ditch may act like a drain during the non -irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ Irrigation: The site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration likely recharges the groundwater. ➢ Alluvial wells: Other than the seven monitoring wells drilled at the site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the site, two wells east of the site, nine wells south of the site and one well west of the site. If pumping, groundwater will be drawn to these wells. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 3 Potential Slurry Wall and Mining Impacts to Local Groundwater Levels For all lined cells, a properly constructed slurry wall will tend to isolate these cells from the surrounding alluvial groundwater table. The liner around these cells could cause "mounding" of groundwater (increase in groundwater elevation) on the upgradient side (southeast) of the lined cells and a potential "shadow effect" (reduction in groundwater level) on the downgradient side (northwest) of the mine. Because the liner will tend to isolate these cells from the surrounding groundwater table, the effects of dewatering when mining lined cells will tend to not extend beyond the liner. Any mounding effect on the upgradient side of the site (south and southwest) is anticipated to be on the order of a few feet or less and will dissipate with distance from the mine. Similarly, shadowing effects will be on the order of a few feet and will dissipate with distance from the mine. The shadowing effects will be minimized by the presence of the South Platte River to the northwest and the Western Mutual Ditch that runs between Cells 5A and 5B and the Farmers Independent Ditch which runs southeast of the site. Dewatering of the unlined cells (Cells 1 and 2) will result in decreases in water levels around these cells. Since there are no wells permitted within 600' of the unlined cells, the effects of dewatering the unlined cells will be minimal. Area Wells A review of the permitted wells on file with the State Engineer's Office (SEO), Division of Water Resources (DWR) indicates that there are nineteen permitted pumping wells within 600 feet of the permit boundary. All of these wells are screened in the alluvium. None of these wells are within 600 feet of the unlined cells (Cells 1 and 2). The well locations and applicants are shown on Figure G-2 attached at the end of this section. Groundwater Level Monitoring and Mitigation Plan Dewatering during mining of Cells 1 and 2 is unlikely to affect any wells in the area. However, if the miner receives a complaint, the following mitigation plan will be implemented. The site monitoring wells will be measured monthly to identify potential changes in alluvial groundwater flow or elevation associated with mining and reclamation activities. Baseline data will be collected prior to dewatering or construction of the slurry walls. Baseline data will be collected from the monitoring program will provide a range of relative water levels associated with pre -mining groundwater conditions. Experience at other mines in similar geologic settings has found that groundwater levels tend to fluctuate being highest in the summer irrigation season and lowest in the winter and early spring. The monthly measurements will be tabulated and included with the DRMS annual report for the site. If, during mining or reclamation, the relative seasonal groundwater elevation at monitoring wells 5 or 6 show mounding of more than two (2) feet, and the condition was not observed during baseline monitoring, or if the miner or the Division receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the DRMS. After the DRMS has been notified, the miner will review the data and available information and submit a report to the DRMS within 30 days. The evaluation will include discussions with the well owner who has contacted the miner regarding a concern and review of baseline data from the well and vicinity to evaluate whether changes may be due to seasonal variations, climate, mining, slurry wall lining or other factors. The report will identify the extent of potential or actual impacts associated with the changes. If the extent of Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 4 groundwater changes due to mining or reclamation activities is determined to be a significant contributing factor that has or may create adverse impacts, the mining associated impacts will be addressed to the satisfaction of the DRMS. Miner will begin implementing one or more mitigation measures if mining and reclamation activity is determined to be a significant factor to groundwater changes requiring mitigation. Mitigation measures may include, but are not limited to: ➢ Placing water in a recharge pond to raise groundwater levels around the well. > Constructing a local clay liner at the edge of the mine Cell (i.e. between the dewatering point and the well) in order to raise water levels on the well side of the liner and mitigate dewatering effects. > Cleaning the well to improve efficiency. > Providing an alternative source of water or purchasing additional water to support historic well use in terms of water quantity and quality. If needed, water quality parameters will be checked in affected wells to ensure alternative sources support historic use. ➢ Modifying a well to operate under lower groundwater conditions. This could include deepening the well or lowering pumps. All work would be done at the miner's expense with the exception of replacing equipment that was non-functional prior to mining. Groundwater Quality Monitoring Plan Since mining operations at the site will take place inside of slurry wall lined cells, except for establishing the Freshwater Pond and Siltation Pond, it is unlikely that these operations will have a negative effect on groundwater quality. To establish pre -mining groundwater quality for the site the permittee will sample MW -2 on the downgradient side of the site and MW -5 on the upgradient side of the site prior to mining. To establish that mining has had no negative affect on water quality in the area, The Operator will sample MW -2 annually during the same quarter as the initial baseline monitoring. The water quality samples will be tested for the analytes listed in Tables 1 through 4 of "The Basic Standards for Ground Water," excluding the radiological section of Table 1. RMCC will notify DRMS within 7 days of receiving a lab report that indicates any of the standards set forth in Tables 1 through 4 have been exceeded. If a lab report indicates an exceedance, a new sample will be taken to verify the exceedance and discount lab contamination. Any water quality lab results will be included in the DRMS annual report for the site. Annual groundwater testing will be conducted for the life of the mine unless the requirement has been reduced or eliminated through the Technical Revision process with the DRMS. Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 5 C3) CIVIL RLS1URCI " 323 Sth STREE I P.O. Boa 600 FREDERICK, CO 8053L 3C3.a33.1A16 W W W .CIV ILR ESOURCE S.COM RED TIERRA EQUITIES RIOT E PRENTICt AVE 9120 GREENWOOD Vt:SAGt., CO RCM )03.771_ 1C07t•i CONTACT DREW DAMIANO SECTION 20 DRMS 112 RECLAMATION PERMIT GILCREST, COLORADO AEV1510Ni MO Dtftil►ttON DATE 1 Cts:GM Hi N la DRAW% •v sit_ caeca(' Iv RIM CATE ti[:U]Cii SCALERS NOTED AS NOTEQ MI NO. 1C1.001.04 CWG NAME jyal A*L* Gt + OL..OW,, • 'a a 1 • NM Know what . below. Call beton you WELLS WITHIN 600 FEET OF PERMIT BOUNDARY EXHIBIT G-2 Section 20 Infiltration Pond - Sizing Calculations Hydraulic Conductivity(ft/day): Pond Size(Acres): Hydraulic Gradient(L/L): 80.51 5.2 (dh/dz)= D„d + D,ov CF s,ze 138.62(K° f ) = 0.05116668 where, D wt = 10 depth from the base of infiltration facility to the water table 2 D pond= 1 depth of water in the pond K= 80.5 saturated vertical hydaulic conductivity CF size= 0.21 correction factor for pond size CF size = O.73(A poed) -o. 7s = 0.21 where, CF size= correction factor for size of the pond A pond= area of the pond bottom in acres Infiltration Rate(f): Discharge Rate(Q): Massmann et al. (2003) f= K(dh/dz) Darcy's Law = 4.1189174 ft/day = 4.7673E-05 ft/sec Q= 10.8046736 CF(siltationbiofouling)- 0.6 Corrected Q= 6.48280414 Massmann et at. (2003) Vertical hydraulic conductivity was assumed to be an order ofmagnatute less than the horizontal hydraulic conductivity used in the MODFLOW model for the area. 2 Assumes water table drop of 10' due to slurry wall installation. CIVIL RES'URCES,LLC ENGINEERS & PLANNERS November 4th, 2022 Mr. Peter Hays Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 RECEIVED NOV 0 4 2022 WELD COUNTY COMMISSIONERS RE: Red Tierra Equities, L.L.C., Section 20 Mine, File No. M-2022-001, 112c Permit Application Adequacy Review 5 Response Dear Mr. Hays: This letter addresses the Adequacy Review letter dated November 3rd, 2022 regarding the Section 20 Gravel Mine 112 Construction Materials Reclamation Permit Application Package. Responses to your comments follow: The following items will need to be addressed to the Division's satisfaction prior to the decision date. If you are unable to satisfactorily address any concerns identified in this review before the decision date, it will be your responsibility to request an extension of the review period. If there are outstanding issues that have not been adequately addressed prior to the end of the review period, and no extension has been requested, the Division may deny this application. Exhibit C - Pre -Mining and Mining Plan Maps (Rule 6.4.3): 1. Please update the Exhibit C maps to show the underdrains and other potential groundwater mounding/shadow mitigation structures discussed in the Groundwater Model. The Exhibit C maps have been updated to show the underdrains/dewatering wells, manhole and infiltration pond discussed in the full mitigation scenario with recharge. A recharge pond will be utilized to mitigate the groundwater shadow effect and to receive water from the underdrains and or dewatering wells. The infiltration pond will be constructed prior to the Cell 4 slurry wall. Exhibit D - Mining Plan (Rule 6.4.4): 2. Please update the Mining Plan according to item 8 below. Included, see response to item 8. 6.4.18 Exhibit R - Proof of Filing with County Clerk and Recorder 3. Please provide an affidavit or receipt indicating the date on which the revised application information required to address this adequacy letter was placed with the Weld County Clerk and Recorder for public review, pursuant to Subparagraph 1.6.2(1)(c). Exhibit N - Source of Legal Right to Enter (Rule 6.4.14) Attached. 4. The Applicant is proposing to install a solid discharge pipe through the Monarch DENM site during Phase 2 of the proposed groundwater mitigation plan. Please provide documentation of the legal right to enter to conduct mining and reclamation, for Owners of Record described in Rule 1.6.2(1)(e)(i). This may include a copy of a lease, deed, abstract of title, a current tax receipt, or a signed statement by the Landowner and acknowledged by a Notary Public stating that the Operator/Applicant has legal right to enter to conduct mining and reclamation. Please note the inclusion of addition affected lands as defined by Rule 1.1(3) would require the Applicant to submit an amendment to the application pursuant to Rule 1.8.1. In order to keep all infrastructure inside the affected area the applicant proposes that water from the eastern underdrain / dewatering wells and the western underdrain will flow to a 5' manhole between Cell 5S and Cell 6. The water collected in this manhole will flow into a 24" solid pipe to the Infiltration Pond north Cell 7. 8308 COLORADO BLVD • SUITE 2❑0 • FIRESTONE, COLORADO 80504 • PHONE: 303.833.1416 • FAx: 303.833.2850 Pu6I;C ReV:ecJ cc:PL(T•/MMu),va(cH/EWc>,c) 2022-237o itfq/22 it/16/2.2 Page 2 Mr. Peter Hays November 4, 2022 The proposed mitigation infrastructure will remain within the affected area and the infiltration pond will mitigate groundwater shadowing to the north. Groundwater Model: 5. As noted on the memorandum cover page, a second underdrain is required to mitigate mounding on the west side of the Section 20 site and will require coordination with Monarch DENM ownership group. If the applicant is unable to get approval from the Monarch ownership an alternate pipeline alignment needs to be proposed. The proposed pipeline will run from south to north along the midsection line to the Infiltration Pond located north of the site. This will keep the infrastructure on the Section 20 site and will mitigate drop in groundwater elevation north of the site. This option is discussed in the Recharge Option in the Groundwater Model Report and is demonstrated in the COMMENTS_INFILPOND model output included in the email version of this letter. The model shows that with the rerouted groundwater being infiltrated north of the site the elevation drop in the wells north of the site is expected to be less than two (2) feet. 6. Please note on page 8, first paragraph, the Sharp house/property spelling is not consistent with Table 3, Table 3A, Table 6 and Figure 6A. Please review the spelling and update the groundwater model text and figures and the Exhibit C maps as required. Spelling has been changed to be consistent with the Weld County Assessor website. 7. On page 8, second paragraph, the Applicant states there are three (3) wells located on the north side of the site that will be in the groundwater shadow. In Exhibit G, the Applicant states there are seven (7) wells located north of the site. What are the groundwater shadow effects on the other four (4) wells located to the north of the site? The Wiedeman Well (# 267997-) is located cross gradient from the site and sees a 0.9 foot rise at full build out of both sites with no mitigation(4717.4' Base condition to 4718.3' at full build out and no mitigation). With the proposed mitigation included in the Mining Plan and Exhibit C the well sees a 0.8' drop from the Base condition(4717.4' base condition to 4716.6' Mitigated condition). Wells 15656-R, 12461-R and 487-WCB are all shown at the same location on the DWR map. These wells were combined to be the Schmidt Well in the Groundwater Model Report since they will see the same drop in groundwater and to avoid confusion of listing multiple wells in the same location. Wells 10222-R and 10223-R are shown at the same location on the DWR map. These wells were combined to be the United Well for the same reason listed for the Schmidt wells. 8. In Section 6.3, first paragraph, the Applicant states the mitigation actions discussed later are "potential" options. The Division expects these mitigation actions to become part of the approved permit and will need to be installed to minimize impacts to hydrologic balance. Therefore, the Applicant needs to commit to installing the mitigation actions and update the Mining Plan (Exhibit D - 6.4.4) to discuss timing and installation of underdrains and/or pumping wells, and address the possible need to install infiltration pond(s) or infiltration gallery along the north side of permit boundary. The Mining Plan (Exhibit D) and the Mining Plan Maps (Exhibit C) have been updated to include the following mitigation structures and timeline: ➢ Infiltration Pond to be mined out during Phase 2 before the construction of the Cell 4 slurry wall. ➢ Eastern underdrain or dewatering wells to be constructed concurrently with the Cell 4 Slurry Wall. Will be piped to a 5' manhole located between Cell 5S and Cell 6. From the Page 3 Mr. Peter Hays November 4, 2022 manhole the water will be piped to the Infiltration Pond to mitigate drop in groundwater elevation to the north. ➢ Western underdrain to be constructed concurrently with the Cell 6 slurry wail. Water will drop into the 5' manhole located between Cell 5S and Cell 6 and will take the solid discharge pipe utilized by the eastern underdrain. 9. Please provide a summary table of monitoring well levels that if exceeded will initiate mitigation efforts. Please note if mitigation actions are planned what the timing of installation is anticipated to be. Mitigation actions will be taken according to the schedule outlined in the Mining Plan (Exhibit D) and above. With the inclusion of the Infiltration Pond in the Mining Plan and Reclamation Plan it is not expected that more mitigation than what is listed will be necessary unless a complaint is made by a property owner or well owner. Red Tierra is still performing baseline monitoring of water levels at the site and will set mitigation initiation water levels for each well once more data is collected and prior to construction of the first slurry wall. The Groundwater Level Monitoring and Mitigation Plan has been updated to state that, "if relative seasonal groundwater elevation at monitoring wells 5 or 6 show mounding of more than two (2) feet, and the condition was not observed during baseline monitoring, or if the miner receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify DRMS." 10. Section 6.3.1, Phase 1 Mitigation, please clarity where the groundwater removed from the southeastern comer will be conveyed to. It appears from Figure 9 the water will be discharged to a 5 foot diameter manhole but from there what happens to the groundwater? The Groundwater Model Report was written to give Red Tierra options on ways to mitigate groundwater mounding and shadow. Phase 1 assumed water would be piped off site and removed from the model. Red Tierra proposes to construct an infiltration pond and thus the Mitigation With Recharge Scenario(Section 6.3.3) will apply. The scenario modeled in Section 6.3.3 utilized the river module to simulate a perforated pipe set in the aggregate, with the bottom of the river set at the pipe invert and the head stage set at the head elevation south of the site. Since Red Tierra is proposing an infiltration pond to the north of Cell 7 the modeling is similar to the scenario described in Section 6.3.3. A separate model run was performed in order to confirm the effects of an infiltration pond versus a perforated pipe and has been included in the email version of this letter (COMMENTS_INFILPOND.gpr). For this iteration of the model, a recharge zone set where the infiltration pond will be located (see Exhibit C). In order to recharge the same amount of water that was removed from the model to the south of the site the infiltration rate was set to 1.45 ft/day. This recharged 562,089 cubic feet per day(6.5 cubic feet per second) into the water table and had the following effects on the wells north of the site: WELL BASELINE WITH RECHARGE CHANGE Schmidt Well 4,714.4' 4,713.4' 1.0' Drop United Well 4,712.0' 4,714.0' 2.0' Rise Owens Well 4,714.2' 4,712.3' 1.9' Drop Wiedeman Well 4717.4 4,716.6' 0.8' Drop 11. Section 6.3.3, Mitigation with Recharge, the Applicant states mitigation efforts will not be initiated until a complaint is received. Mitigation efforts include the installation of an infiltration pond and/or gallery to recharge groundwater. These efforts may take a long enough time to take effect that the Page 4 Mr. Peter Hays November 4, 2022 complainant will be without sufficient water for an unacceptable amount of time. Please propose a near term mitigation solution until the long-term mitigation proposed can take full effect. Red Tierra proposes installing an infiltration pond as described above to mitigate shadowing north of the site. Near term mitigation solutions are included in Exhibit G and include: ➢ Cleaning the well to improve efficiency. > Providing an alternative source of water or purchasing additional water to support historic well use in terms of water quantity and quality. If needed, water quality parameters will be checked in affected wells to ensure alternative sources support historic use. ➢ Modifying a well to operate under lower groundwater conditions. This could include deepening the well or lowering pumps. All work would be done at the miner's expense with the exception of replacing equipment that was non-functional prior to mining. 12. All mitigation underdrains, pumps and associated infrastructure appear to overlap the proposed locations of various gas pipelines. Please explain how the timing of installation will be effected and what the possible impacts of one on the other are. The mitigation underdrains will cross some existing gas lines. The underdrains will likely be significantly deeper than the existing gas lines and Red Tierra will work out an agreement for crossing these lines with the owner. It is not anticipated that existing or future gas lines will be an impediment to installation of the mitigation structures. 13. Conclusions, the first bullet indicates the quantity of water to be pumped to the river at full build out will be 6.5 cubic feet per day or about 49 gallons per day, this volume appears to be incorrect. Please update value. Conclusion has been changed to 6.5 CFS. Please feel free to contact me with any questions or concerns at Kyleacivilresources.com or my cell number 408-930-2544. Regards, CIVIL RESOURCES, LLC Kyle Regan Project Geologist J:IUnited Water& San-1411Section 201DRMSICorrespondencelDRMSIAdequacylGroundwater Model Response_10102022.doc CLMA7IA.'tr0 M7GL'fSS u T .NO $tcws IR•Jra DISCHARGE Paul Q LrSCINN!.E POW! l 1 OVl SBYRDIN flocs tat 8 BERM O 4.97 ) SWIM WALL 1.177 V 1--T MOTES. MIMING AT A 3.1 Mut L,/ L1. MAILS A INt 0 EACH L 10 MIME [ACM rMSt 1111.1E NOTE.C:63 AM AG! RATE W LOOC,. TOSS TONS GAT OF Of AGGREGATE PH YEAR AND 1.3 TOMS OF AGGREG AGGREGATE PER CYSIC Maki.� e�CR-N l_�_ � �f� a Ma a-ataa a-�a aea l; SWIM WALL CYRTAW YEAS ASSUME THAT ADJACENT CELLS WELL LIMA! ONE LI.S ONE I s.a+ I JO. 00 ONIOING SWIM MALL a. swim ri.CO { 1 1 t { wAu Curia A mAu ASSuMt Tit! t FOLLOWING AVERAGE DEPTH To mow 1 I •ail3 so CIVIL RE S IPU R C E: S w • CELL. S3' 1* tY' _ _ V • CELL 3 Sr ALONG wHH 1M �BlER. YO AI0NG SOYTNEAN Ali _- _ _ I - CELL / - - -CIiLr SS' Stn STREET MASI 2 WrITRAT10N POYD ,�.•• J. • CELL 7 S3'323 ` •A 't• ctu r so' P.O. Bo>r 610 I .:, 1, PHASE �) i C,`\ _r , • 1 , 707.1]7.1416 _11 CELL 2 . -.�-v ' WWW.CIVILAESOURCES.COM SILT POND DISCHARGE u t r ' INFILTRATION 1 APPROX 35 - POND CELL 3 Ni: I' CELL ) ' I ACRES Q Olt) 5TOR Stl2 AC -FT I SECTION 20 14313 WattT ►[ARSES LW. 1 PMSt 1 I )..A.A. 1 •2.B CAL ) •'� 1 1 II I rHwu , Via 40..1., 3.7918S TO CURT AN SW . CELL A SLUM w ELL I 1 MINT 1 411E C=_LL I PNA� AfffASQ•FT I3.374 LP 4 I _ 8 Lett / I s �-ti a-- R - N.rt S 'LL t PAP NA RED TIERRA EQUITIES, LLC I ►MALE l }..r-��- -__. -_ —� :- r)01t►RENT�t AVE inc IA'C L2W NA M 1\___.____________- _-,� me -„«,-+yy._� �- _ - - _. •�� ` - -I GrltMWOOD VItLAf2. co /0311 CELL 1 - -- r " W. 00 SSi00 - - . . C y 301.711.1005 Hp) h I FRESH WATER • ++ crtr•. I i CONTACT DREW DANIANO POND APPROX } I�� II cPs w ' 1: 3 3 II ACRES TO BE r►rna INCLUDED I M- Cru st I •�- ,� r -�, � I r AGGREGA Ig ` . CELL 7 STORAGE: 1,619 AC -FT �su�a, MOO lAsleRN urDCROMIM OM PLANT I R_ t' ( l 3 t CEWATtIING WMILS IMSTAUID CONCURNANT WITH CtLL • f� C3 ! (A1MAOR )otWATtlING WELLSJl OR2.L00Or2sSLDTton►t) 3STORAGE:1713aC-FT`;, L XLJLUPIW CKL • it ,D ,v p jsc: PMAS[ �1 • • xVPr. WILL. I 0 ,I 03 + 2 •CELL ,• 1.1Ce to O 1.L J ') O ' ASPHALT r PLANT t 10 • ter.. tc SCOILTR LIrE CELL a Cci1371 512D00 N Q O ' ACRES •: •- �. O 1M.lilMTiDM 1 5TOkAGC °,6] 7 AL -FT hu 1.1 I ••� L c O >,• POND •.721U G• T I on-mReo Wall TH! SWt1MS/ON 01. O U - - 11 ? , I} j' _ g OrJICE ANC SHOT _ ... _ - -a-acct. L =a-7 II�Lti�.� _ —�_ _ El 38ICEIL6531 NA I�.C.1111. ; • p ..--- W F . ail_ ., ,..IW ' 1 + I .,:j LU • ....._-_...—..� .._ ti `I �rN+r►.y !' �....rs��.-� rur.��... .�r�� GA 1 _—s. '//1 1/ ��.�1 __ �• - _ )►.51 -� J 1T^ „• �J. Qi �` lm �. • ]br I . _ j 1 1 ? NAME S. uB.n r.a - _�. — . -"r title OAT! Ni C.� — 9" • A r rt R. J - _• - 0 — .- (TAW I... 69 4 QYAWIEO AS A PROFESSIONAL CEOIOGIST AS ri i z t lb �~1•t1 - - _- - - EX wtu {ACIUTr crib,,,,. WHTERN fNOEWMAIN DEFINED W COLORADO SIATYTL. V rlbw.r tenants r�'- '• , ^ N I 10 ACRES . 1 11 3 t11{ • 11.0 4 IS 00 4 SLOTTED PIPE S 11 o ' CELL SN I ►ARSE 1 au" /•1 I LEGEND: • MALE 3 CM III s17 4. CaL411 365300 PHASE• I I to N In I B� PROPOSED PERMIT BOUNDARY PHASE 1 ;; _ Ii-P-T*4*i H I+i+F•H-ri H1 1 SLURRY WALL ALIGNMENT CNL 3 SLURRY WAWALLMD CELL • ' 1 r4.711f Is PHASE I • • ED 1 . . r 09 4 - — PROPOSED MINE LIMIT REVISIONS , (+ NO DlfCR1►Yi0M ISM CELL SN ,I PROPOSED MAJOR CONTOUR PROPOSE RELVCATEL Df F STORAGE: 2,575 AC -FT ; 1. CELL771 27[.110 GAS UNE • MSS LF PROPOSED MINOR CONTOUR p C 9 I I15 Li ; EXISTING BARBED WIRE FENCE - - +t.- 4 -1EXISTING EDGE Of PAVEMENT G►s t, ZEIP2P4-4•• TD kE rCMO,itL 6 1 - 'Ili N FloM J 1 G _ /18)00 EXISTING EASEMENT STORAGE: 5,747 AC -FT O 1 r wAu _- / ti SECTION LINE C S , r CELL S OINKING SLUM WALL SLURRY )C.0 + 2CJTiAIESTOTAI EXISTING RIGHT OF WAY ` 7.190 LF CCU 2.102 Lf PRASE • 1 Jr L' ctiLPriAS 1NPHASE :PHASCELL SS . • ... : 3 9 • , AC 1 n ttLL Xn __►UTUM NMI! ASlil / I N TO SE INCLUDED IN 1 EXISTING DIRT ROAD Dlz104ta rV DATC/(k2C21 CO A'AFTER SOLO OR01 DI TO S M. Ut TO 1 1 fr{+ r Sul Duwr BY rcwLEAs NOTED MART IEMOVAS4 wEs11w. • ,33.0' 8 1 : ` EXISTING BURIED ELECTRICAL r III EAS111W: •.)is.l' � CH[iMtD in )u((_ /LS NOM I •', III)1451.04 NOM I EXISTING OVERHEAD ELECTRICAL No. wA:` , 43 • I ,,- • DWG MME GILCRISTWICA-GIOLOG1.Dwi DWG es,tMA I 1 1 ... •-,..e., - _ EXISTING FIBER OPTIC rstNi. qr., C WATERWAY -'- ��`� 5 � / JO •00 ■,�, rlrvr — — cc�`7.a I.: a°'°� ��Jvj1S • MINE PLAN % .f _ _ MONITORING _ • 1 URTI AND _ -mat l�a^�_.- # s �- -_ RLANDSG►tD ELECTRICAL _ __�. - _ _.._ .- _a _ _ ,,.•t a BOX TIMELINE EL: 4. ir 811 0 OVERHEAD ELECTRIC POLE INv El pp QNDERWA2N TRANSITION TO urDERORAIr A n MIMING ALONG • IC FROM SLURRY WALL SOLID PIPE 1W FROM SLURRY WALL OE SERIES OF RING WELLS ` NEIGHBORS TO It CONSTRUCTED V PROPERTY UNE • o at c Ito TO St CONSTRUCTED SHEET CONCURRENTLY WITH . CONCURRENTLY w[TH CELL 1 (OtSIGN WILL u CELL•SE boa PROVIDED TO DIMS PRIOR TO CONSTRUCTION) illOW Wes PROV to DINS :104 TOC CONSTRUCTION[ day. EXHIBIT C- 5 t-1 CC 1 1 I I 1 i I 1 I I n CQMNc4f0 ARXfSS I O S.UAWArwfw 06c.4At ( agvr 8 OVEtnlaOtN STOCKPILE a>:-=.EIF Fa C[.4 1 ae n• la Me or as _ stiim Pt_ Al TOPSOIL STOCKPILE CELL 2 Cell t PHASE 1 OVERSUROtN STOCKP122 CELLI CELL 0 PHASE ) O CELL• PHASE 2 COLLt PHASE FUTURE ROME AIWA TO WI INCLUDED IN Cal t (AFTER SOCAt ARRAY REMOVAL) aw --.. ►- - _- `s _ ems_ r-� Jr—+� TOPSOIL STOCKPILE CELL / as ena AV a s 4'f r. irr ^C /Aril ril4tA, e CELL SS PHASE I O L fJ ❑ O 00 RI CELL SS PHASE 2 3•00 ~ 10 A7 u a -1 •0D 2$•W _�-tt f- 11y I .1 I P •t..y.0 f rA •. Ifs. Cl f We. Erie.. C I•I-.e, CELL SS PILAU I INI1.—.. (C3. CELL SS PHASE 4 I I I $ Oc Sow '°'irisisai.g.4 JO' Ntr[ Sion // I I I I/ I T// I T I I I\1 Lion, TYPICAL MINE SECTION LEGEND: 0)• S S 01• 51• S a PROPOSED PERMIT BOUNDARY I+++I l I l H I+1 1 1 I l l 1 I F I ♦♦ K i l l SLURRY WALL ALIGNMENT PROPOSED MINE LIMIT PROPOSED MAJOR CONTOUR PROPOSED MINOR CONTOUR EXISTING BARBED WIRE FENCE EXISTING EDGE OF PAVEMENT EXISTING EASEMENT SECTION LINE EXISTING RIGHT OF WAY PROPOSED COPWEYOR EXISTING GAS LINE EXISTING WATER LINE PROPOSED ACCESS ROAD EXISTING DIRT ROAD EXISTING BURIED ELECTRICAL EXISTING OVERHEAD ELECTRICAL EXISTING FIBER OPTIC WATERWAY { MONITORING WELLS O3 ELECTRICAL BOX A OVERHEAD ELECTRIC POLE / PREPAIEO UNDER The SUPERVISION OP: NAME KIN S. Row P.C. DATE QUALIFIED AS A PROFESSIONAL GEOLOGIST AS DEFINED ET COLORADO STATUTE. ertool LI%It RI.S1URCCS 323 5th STREET P.O. Boa 600 FREDERICK. CO 00530 303.533.1416 www.civiLREsouRCEs.com RED TIERRA EQUmES, LLC 2101E ►RENTICE AVE 1110 GREENWOOD VILLAGE. CO 00111 102.271.1001 IN) CONTACT DREW DAMMED SECTION 20 DRMS 112 RECLAMATION PERMIT GILCREST, COLORADO NEVISIONS 160 DESCRIPTION DATE DESIGNED tY HEEL DRAWN IY ja_ CHECKED IV RuL JOB NO. 101.OOLD4 DAR. j/1W20II SCALISE NOTED AS NOTPD DWG NAME-clLCRtST•AREA-GZOKOGY.DWE MINE PLAN STOCK PILE LOCATIONS EXHIBIT C-6 ee..ur reuro.s Rne b _ j PH3 9114 Ts1 n 4t�ecs�oe�ELL D� I❑ MCI. IOM _mtaY 7. vn E 1 lilccE F NiNOPRI3E CM CHI csvluDl�'1 145455 It 15 EFLLBNFr CI CF l�l el 11 el el s,Si14 LL4D66 tl CELL rx p to yrw,l tl 11 el IP xlvN tl tl ctLLtlrx EI 41 11a LEGEND b191D cEuryrwxl Hm uaPI 11 mLwPwsl r4uavw.l •IIaPw11 rwm��wmw�. s< 011 PROPOSE. n1xOR CON CI., I. EASENEM IMI - E[ISTEN-7,7 wAv ..a.—� �..,.� �. �.� PROPOSE D t l(ISi1NG s LINE I t x EYISIINO WATER LINE /� I j _ — PItOPOeE. A¢Ess IFw0 ,g ®�®�� ' J t t Evlsrlxc BIRi Rw. P ,11 .:,, El£C)R1GL B"o 1 a E.l,iwERnEA.ELLRR1�, II O lip, D E.I=<I-,..ER.r,I. mV J� � _ _ wA)ERwAi --..,-,,,,,,,,-_,--_—_,,,,,,,,7,—,J_ § no,..... weus - - � _ � EIEnAtul. sax OVE0.nEA. ELERRIO POLE CC RE�T1E0.0.A EQUIi1E51 ,LC Q W a U J- ry Z 52' � E e u. wn LLIIOll_ Sun4yypp_ AsnRnR__ RECLAMATION PLAN AND TIMELINE F-1 EXHIBIT D — MINING PLAN The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.4.4 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Description of the method(s) of mining to be employed in each stage of the operation as related to any surface disturbance on affected lands; The permit area includes a significant deposit of sand and gravel located in the alluvium of the South Platte River in Weld County. The site is located south of Highway 66, west of Weld County Road 19, north of Weld County Road 28 and east of Weld County Road 17. It encompasses 631.58 acres (plus or minus) and consists of seven slurry wall lined, and an unlined silt pond. Prior to starting construction of any slurry wall, a Technical Revision to update the site bonding will be applied for and will include the slurry wall design report. Site Preparation: Initial disturbance on the property will be stripping overburden in the eastern portion of Cell 8 to establish the plant footprint. Concurrently with establishing the plant, the first phase of the Fresh Water Pond and the first phase of the Siltation Pond will be stripped of overburden and mining will commence in these phases once the plant has been established. After the initial preparation of the Plant, Fresh Water Pond and Siltation Pond, the Concrete Batch Plant and Asphalt Plant areas will be established and constructed. Customer roads will be established from the entrance to the plant areas. The current house on the west side of the property will be utilized as the office and a shop will be constructed in the early phases of site development. A parking area for employees will be constructed adjacent to the office and shop area. Mining: Scrapers will strip the topsoil and overburden material from a given phase and place stockpiles in the processing area. Any excess material not needed for reclamation may be sold or hauled off -site during the life of the mine. There will be no mining below the groundwater table until the slurry wall is complete, tested and approved for each slurry wall lined cell. For unlined cells, there will be no mining below the groundwater table until an approved Substitute Water Supply Plan(SWSP) has been obtained. Each slurry wall lined phase will be dry -mined using scrapers, bulldozers, front-end loaders, excavators, or similar equipment. The Fresh Water Pond and Siltation Pond will be unlined an wet mined with excavators. Mining at the site will progress in eight major stages comprised of minor phases expected to last approximately one year. A map depicting the phases can be found in Exhibit C-5. Stage 1 - will establish the Aggregate Plant, the Siltation Pond, the Freshwater Pond, and will mine out the future commercial area in the south-west comer of the site. These areas, excluding the Aggregate Plant, will be wet mined with excavators. Stage 1 is expected to last approximately 2 years. Topsoil mined from phase one will be segregated and utilized to establish a berm along the north-western boundary of the site along Weld County Road 44 and Colorado State Highway Section 20 — Gravel Mine — MLRB 112 Permit Amendment Exhibit D -1 66. After the berm has been established the remaining segregated topsoil will be stockpiled in the northern portion of Cell 7. Overburden, clay and any other material that is uneconomical to sell will be stockpiled in the northern portion of Cell 7 to be used in Stage 2 slope reclamation. Stage 2 - will consist of mining out Cell 3 in the north-east corner of the site. Mining will be completed in three (3) year long phases and will progress from west to east. Cell 3 will be a slurry wall lined cell and will be dry mined. The Infiltration Pond north of Cell 7 will be mined out concurrent with Cell 3. The Infiltration Pond will be mined to approximately 10 to 15 feet deep and will not encounter the water table. If the groundwater is encountered the area of the pit below the groundwater table will be filled with aggregate to approximately two (2) feet above the elevation where groundwater was encountered. Topsoil from this stage will be segregated and stockpiled in the northern portion of Cell 7. In the initial phase, overburden will be stockpiled existing stockpile in Cell 7. Once the first phase has been completely mined out, reclamation will begin on that phase and overburden material from the other phases will be placed directly in the reclamation slopes or sold. Stage 3 — will consist of mining out Cell 4 and concurrently reclaiming Cell 3. Cell 4 contains three (3) approximately one (1) year phases. Cell 4 will be a slurry wall lined cell and will be dry mined. Concurrent with Cell 4 slurry wall construction the southeast underdrain or series of dewatering wells will be constructed south of Cell 5S. Water from this area will be rerouted to the infiltration pond excavated in Stage 2 to mitigate the drop in groundwater elevation north of the site due to slurry wall construction. Topsoil from this stage will be segregate and stockpiled in the northern portion of Cell 7 as indicated on the map. Slope reclamation of the previous phases will be concurrent with mining. Overburden will be placed in the reclamation slope or stockpiled in the bottom of the pit next to the current reclamation phase. Excess overburden will be placed in the southwest corner of Cell 6 to fill in the future commercial area. Stage 4 — will consist of mining out Cell 5 and concurrently reclaiming Cell 4. Cell 5 contains seven (7) approximately one (1) year phases. Cell 5 will be a slurry wall lined cell and will be dry mined. Topsoil from this stage wilt be segregate and stockpiled in the northern portion of Cell 7 as indicated on the map. Slope reclamation of the previous phases will be concurrent with mining. Overburden will be placed in the reclamation slope or stockpiled in the bottom of the pit next to the current reclamation phase. Stage 5 — will consist of mining out Cell 6 and concurrently reclaiming Cell 5. Cell 6 contains four (4) approximately one (1) year phases. Cell 6 will be a slurry wall lined cell and will be dry mined. The southwest underdrain will be constructed during the construction of the Cell 6 slurry wall. Water will be rerouted from the southern end of the site by the underdrain and piped to the Infiltration Pond to mitigate the groundwater shadow affect north of the site. Section 20 — Gravel Mine — MLRB 112 Permit Amendment Exhibit D - 2 Topsoil from this stage will be segregate and stockpiled in the western portion of Cell 2(Siltation Pit) to be utilized in reclamation of the silt pond back to native grade. Slope reclamation of the previous phases will be concurrent with mining. Overburden will be placed in the reclamation slope or stockpiled in the bottom of the pit next to the current reclamation phase. Any overburden not used in slope reclamation will be placed in the unused portion of Cell 2(Siltation Pond). Stage 6 — will consist of mining out Cell 7 and concurrently reclaiming Cell 6. Cell 7 contains four (2) approximately one (1) year phases. Cell 6 will be a slurry wall lined cell and will be dry mined. Topsoil from this stage will be segregate and stockpiled in the western portion of Cell 2(Siltation Pit) to be utilized in reclamation of the silt pond back to native grade. Slope reclamation of the previous phases will be concurrent with mining. Overburden will be placed in the reclamation slope or stockpiled in the bottom of the pit next to the current reclamation phase. Any overburden not used in slope reclamation will be placed in the unused portion of Cell 2(Siltation Pond). Stage 7 — the final stage will begin with mining out the aggregate under the Asphalt Plant, the Concrete Batch Plant and the office area. The last portion to be mined out will be the Aggregate Plant. Stage 7 will take approximately two (2) years and will establish Cell 8. Topsoil from this stage will be segregate and stockpiled in the western portion of Cell 2(Siltation Pit) to be utilized in reclamation of the silt pond back to native grade. Once mining is complete at the site, the topsoil berm will be mined and used in any areas needing topsoil for reclamation. Slope reclamation of the previous phases will be concurrent with mining. Overburden will be placed in the reclamation slope or stockpiled in the bottom of the pit next to the current reclamation phase. Any overburden not used in slope reclamation will be placed in the unused portion of Cell 2(Siltation Pond). The operator will develop and comply with a Stormwater Management Plan and Spill, Prevention, Control and Countermeasures Plan. The operator will notify the Division of Reclamation and Mine Safety and in the event of a reportable spill. Processing: The material will be dry screened or not screened at all and transported offsite by truck. The processing area will be located on the south side of the site in Cell 8. Import Material: The Operator may import material from and export material to other sites. The applicant is aware that in accordance with Rule 3.1.5(9) of the Construction Material Rules and Regulations, if any offsite material is used as backfill, a notarized letter will be submitted to the Division indicating the materials are inert. The applicant will supply such a letter to the Division if, at the time of Reclamation, the applicant intends to use off -site material as backfill. (b) Earthmoving; Section 20 - Gravel Mine — MLRB 112 Permit Amendment Exhibit D - 3 Topsoil and overburden will be stripped with scrapers or bulldozers and stockpiled in segregated piles at the edge of the active mine phase or as described above and shown in Figure C-6. Excavators, front-end loaders, and bulldozers will be used to excavate the material. Haul trucks will be utilized to transport the raw material from the active mine phase to the processing area. See Exhibit C-6 for a cross-section of side -slope mining; mining will take place at a 3 to 1 mine slope and reclaimed at a 3:1 reclamation slope. The Miner may, in the future, decide to mine at a 1.5 to 1 slope and reclaim with a 4:1 slope in which case the mine plan will be updated through the Technical Revision process. Since the Minerforsees this as a possibility, the slope stability analysis was conducted at the worst case scenario of a 1.5 to 1 mine slope. (c) All water diversions and impoundments; Storm water will be discharged per a CDPHE discharge permit. There are no planned diversions or impoundments of existing water bodies. A wash cycle for the aggregate processing area will be established using the freshwater pond as a source and the silt pond for return flow, with natural groundwater filtration between the source pond and the return pond. Any water consumed will be provided by the existing water rights associated with the property and/or a groundwater well with associated substitute water supply plan (see Exhibit G). (d) The size of area(s) to be worked at any one time. Each phase is approximately 25-30 acres in size. The Operator will mine multiple phases concurrently in order to obtain a range of material for production. In addition to mining, the Operator, will begin reclaiming slopes as mining is finished in each stage. Since multiple phases will be being worked at any one time, the approximate size of the areas to be worked at any one time will range from 25 acres to 120 acres and will depend on market conditions. (e) An approximate timetable to describe the mining operation. The timetable is for the purpose of establishing the relationship between mining and reclamation during the different phases of a mining operation. The Operator anticipates that mining will commence as soon as all permits are in place. The Operator anticipates extracting approximately 2,000,000 tons of aggregate in a typical year, up to 3,000,000 tons at peak capacity. Production rate will vary based on market demands. Section 20 — Gravel Mine — MLRB 112 Permit Amendment Exhibit D - 4 Timetable for Mining and Reclamation MINING AND RECLAMATION TIMETABLE YEAR MINING PHASE RECLAMATION PHASE 1 CELL 1 CELL 2(PHASE 1) CELL 8(PHASE 1&2) OB 2 CELL 3(PH-1) 3 CELL 3(PH-2) CELL 3(PH-1) 4 CELL 3(PH-3) CELL 3(PH-2) 5 CELL 4(PH-1) CELL 3(PH-3) 6 CELL 4(PH-2) CELL 4(PH-1) 7 to 8 CELL 4(PH-3) CELL 4(PH-2) CELL 2(PH-2) 9 CELL SN(PH-1) CELL 4(PH-3) 10 CELL 5N(PH-2) CELL 5N(PH-1) 11 CELL 5N(PH-3) CELL 5N(PH-2) 12 CELL 5S(PH-1) CELL 5N(PH-3) 13 CELL SS(PH-2) CELL 5S(PH-1) 14 CELL SS(PH-3) CELL 5S(PH-2) 15-16 CELL SS(PH-4) CELL SS(PH-3) CELL 2(PH 3) 17 CELL 6(PH-1) CELL 5S(PH-4) 18 CELL 6(PH-2) CELL 6(PH-1) 19 CELL 6(PH-3) - CELL 6(PH-2) 20 CELL 6(PH-4) CELL 6(PH-3) 21 CELL 7(PH-1) CELL 6(PH-4) 22 CELL 7(PH-2) CELL 7(PH-1) 23 CELL 8(PH-1)CS ONLY+ CELL 7(PH-2) 24 CELL 8(PH-2)CS ONLY+ Cell 8(PH-1) 25 aspami Cell 8(PH-2) (t) Use Mining Plan Map in conjunction with narrative to present: Section 20 — Gravel Mine — MLRB 112 Permit Amendment Exhibit D - 5 Nature, depth and thickness of the deposit and thickness and type of overburden to be removed Overburden consists mainly of silty fine grain sand transitioning to sandy silt. Overburden thickness varied across the site from non-existent in the southwest corner to 15 feet thick in the southeast. The aggregate reserves at the site consist mainly of gravelly sand which grades to sandy gravel, usually becoming more gravelly with depth. Some cobble units (grain size 4" or greater) were encountered at the site; mainly consisting of a few feet overlaying bedrock. Aggregate unit thickness varied from 35 feet in BH-36 in the northern side of the site to 72.5 feet in BH-27 in the eastern side of the site. There is a large contiguous clay seam that encompasses almost the entire site. The clay seam varies from only 1 foot of thickness in the northwest to 23 feet of thickness in the southeast corner of the site. (ii.) Nature of the stratum immediately beneath the material to be mined in sedimentary deposits Depth to bedrock ranges from 39.5 feet in BH-38 in the northeast corner of the site to 97.5 feet in BH-41 in the southeast corner of the site. The bedrock encountered at the site consists of wet brown weathered claystone in the first 6 inches to 1 foot which transitioned into moist to dry, olive to grey claystone with further depth. (g) Identify the primary and secondary commodities to be mined/extracted and describe the intended use. The primary commodities are sand, gravel and fill; intended for construction materials. (h) Name and describe the intended use of all expected incidental products to be mined/extracted by the proposed operation. Gold may be extracted as an adjunct component of any wash equipment installed at the site. (►) Specify if explosives will be used in conjunction with the mining (or reclamation) No explosive material will be used on -site. (j) Specify the dimensions of any existing or proposed roads that will be used for the mining operation. Describe any improvements necessary on existing roads and the specifications to be used in the construction of new roads. New or improved roads must be included as part of the affected lands and permitted acreage. Affected land shall not include off -site roads which existed prior to the date on which notice was given or permit application was made to the office and which were constructed for purposes unrelated to the proposed mining operation and which will not be substantially upgrades to support the mining operation. Describe any assocated drainage and runoff conveyance structures to include sufficient information to evaluate structure sizing. Section 20 — Gravel Mine — MLRB 112 Permit Amendment Exhibit D - 6 The affected land and permitted acreage is inclusive of over one and one-half miles of land directly abutting public roadways; there is no need for any additional driveways, and on -site haul roads will be incidental to mining areas depicted on the Mining Plan Map. No roadways are affected by the mining operation other than access roads within the permit boundary and existing public roads to the site. The Operator will apply for a Weld County Access Permit for the site. Section 20 — Gravel Mine — MLRB 112 Permit Amendment Exhibit D-7 EXHIBIT G — WATER INFORMATION This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.4.7 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Locate on the map (Exhibit C) tributary water courses, wells, springs, stock water ponds, reservoirs and ditches The site is 0.4 miles east of the South Platte River. Please refer to Exhibit C for locations of water courses in close proximity to the site, including wells, springs, stock water ponds, reservoirs and ditches. (b) Identify all known aquifers The site is underlain by a shallow alluvial aquifer, typical of its position upgradient of the South Platte River. (c) Show how water from dewatering operations or runoff from disturbed areas, piled material and operating surfaces will be managed to protect against pollution of either surface or groundwater both during and after the operation. Please refer to the Mining Plan Map in Exhibit C-5 of this application. Mine areas will drain internally. Uncontrolled releases of surface water in disturbed areas will not occur. Stormwater collected in the active mine area will be managed through the dewatering system. Dewatering will be accomplished by digging a sump, generally along the base of the mine slope, which will hold a floating pump. The pump will have an HDPE discharge line that will be routed to one of the comingled discharge points located at the site. The pump will be powered by a diesel generator housed in the active mine area. The Operator will apply for and receive a comingled stormwater and process water discharge permit prior to dewatering at the site. (d) Estimate project water requirements including flow rates and annual volumes for the development, mining and reclamation phases of the project. Water needs estimated below provide for sustained production as detailed in the Mining Plan. The Operator will adjust water supplies to account for actual demand, avoid waste, and continuously comply with laws and regulations of the Division of Water Resources and any other water agency having jurisdiction over the operation. Projected Use And Consumption: Annual evaporative depletions will be the evaporation from up to 5000 feet of 4 -foot wide de -watering trench, located inside of the slurry wall. The total area of exposed water is 0.5 acres. The gross annual evaporation at the Section 20 Mine is 42 inches according to NOAA Technical Report NWS 33, Evaporation Atlas for the Contiguous 48 United States. Monthly evaporative losses are determined using percentages specified by the State Engineer's Office for locations below 6,300 feet. The nearest weather station is in Longmont where the average annual precipitation is 15.08. Effective Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G -1 precipitation, that part of historical precipitation which was consumed by native vegetation on land to be covered by water surface, is conservatively estimated to be 70 percent of the total precipitation. The annual average effective precipitation at the property is estimated to be 9.09 inches. When subtracting the effective precipitation from the gross evaporation yields, the net annual evaporation is 31.44 inches, or 2.68 acre-feet per acre. The Fresh Water Pond is approximately 10 acres and the Siltation Pond will be utilized in 10 acre stages. The approximate acreage of open water surface is 20.5 acres. The annual amount of evaporation from open water surfaces is 54.9 acre-feet. Mining Production & Operations: The Operator expects to extract approximately 2 million tons annually of aggregate material from the site. All water retained in the recovered material will be replaced pursuant to the Substitute Water Supply Plan (SWSP). The total annual amount of water retained in the gravel product from mining activities totals approximately 27.2 acre-feet. The SWSP is renewed annually and will reflect analysis of production and depletion anticipated in each year of operation. In addition, an estimated 4.0 acre-feet of water per year will be used for dust control based (approximately) on 5,900 gallons per day for 5 days a week for 10 months. Annually the total evaporative and operational losses from mining activities (open water surface evaporation, water retained in the aggregate product, dust suppression) totals 86.1 acre-feet of depletion which must be augmented. All depletions were lagged to the Saint Vrain River using the lagging factors approved by the State Engineer pursuant to on -going Substitute Water Supply (SWSP) approvals. (e) Indicate the projected amounts of the water sources to supply project water requirements Replacement Water: The Miner will obtain an approved Substitute Water Supply Plan from the State Engineers office every year, providing annually or more frequently the opportunity to review the sufficiency of water supplies. The SWSP approvals require that the applicant provide a detailed explanation of the mining operations, a quantification of all mining activities and subsequent depletions and all legally available replacement sources. (f) Affirmatively state that the Applicant has acquired or applied fora National Pollutant Discharge Elimination System permit from the Water Quality Control Division The Operator will apply fora National Pollutant Discharge Elimination System (NPDES) permit from the Water Quality Control Division of the Colorado Department of Public Health and Environment prior to discharging water from the site. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 2 Groundwater Sampling and Analysis Plan This information provided in this subsection of Exhibit G is intended to satisfy the requirements outlined in the Groundwater Monitoring and Protection Technical Bulletin dated November 19, 2019: Existing Groundwater Conditions The near surface groundwater is part of an alluvial aquifer in which permeable sand and gravel alluvium overlies relatively impermeable bedrock of either the Fox Hills Sandstone and/or the Laramie Formation. Groundwater, measured in 7 piezometers, occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the site. The prevailing groundwater flow at the site is to the north reflecting the site topography. Groundwater in the area is tributary to the South Platte River located northwest of the site. Locally the groundwater levels and flow directions are likely influenced by: ➢ The South Platte River is northwest of the site. For most of the year, the river likely acts as a drainage way maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the site under the intersection of Weld County Road 42 and Weld County Road 29. The ditch may act like a drain during the non - irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ The Farmers Independent Ditch traverses the southeast corner of the site and bisects Cell 5a and 5b. The ditch may act like a drain during the non -irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ Irrigation: The site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration likely recharges the groundwater. ➢ Alluvial wells: Other than the seven monitoring wells drilled at the site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the site, two wells east of the site, nine wells south of the site and one well west of the site. If pumping, groundwater will be drawn to these wells. Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 3 Potential Slurry Wall and Mining Impacts to Local Groundwater Levels For all lined cells, a properly constructed slurry wall will tend to isolate these cells from the surrounding alluvial groundwater table. The liner around these cells could cause "mounding" of groundwater (increase in groundwater elevation) on the upgradient side (southeast) of the lined cells and a potential "shadow effect" (reduction in groundwater level) on the downgradient side (northwest) of the mine. Because the liner will tend to isolate these cells from the surrounding groundwater table, the effects of dewatering when mining lined cells will tend to not extend beyond the liner. Any mounding effect on the upgradient side of the site (south and southwest) is anticipated to be on the order of a few feet or less and will dissipate with distance from the mine. Similarly, shadowing effects will be on the order of a few feet and will dissipate with distance from the mine. The shadowing effects will be minimized by the presence of the South Platte River to the northwest and the Western Mutual Ditch that runs between Cells 5A and 5B and the Farmers Independent Ditch which runs southeast of the site. Dewatering of the unlined cells (Cells 1 and 2) will result in decreases in water levels around these cells. Since there are no wells permitted within 600' of the unlined cells, the effects of dewatering the unlined cells will be minimal. Area Wells A review of the permitted wells on file with the State Engineer's Office (SEO), Division of Water Resources (DWR) indicates that there are nineteen permitted pumping wells within 600 feet of the permit boundary. All of these wells are screened in the alluvium. None of these wells are within 600 feet of the unlined cells (Cells 1 and 2). The well locations and applicants are shown on Figure G-2 attached at the end of this section. Groundwater Level Monitoring and Mitigation Plan Dewatering during mining of Cells 1 and 2 is unlikely to affect any wells in the area. However, if the miner receives a complaint, the following mitigation plan will be implemented. The site monitoring wells will be measured monthly to identify potential changes in alluvial groundwater flow or elevation associated with mining and reclamation activities. Baseline data will be collected prior to dewatering or construction of the slurry walls. Baseline data will be collected from the monitoring program will provide a range of relative water levels associated with pre -mining groundwater conditions. Experience at other mines in similar geologic settings has found that groundwater levels tend to fluctuate being highest in the summer irrigation season and lowest in the winter and early spring. The monthly measurements will be tabulated and included with the DRMS annual report for the site. If, during mining or reclamation, the relative seasonal groundwater elevation at monitoring wells 5 or 6 show mounding of more than two (2) feet, and the condition was not observed during baseline monitoring, or if the miner receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the DRMS. After the DRMS has been notified, the miner will review the data and available information and submit a report to the DRMS within 30 days. The evaluation will include discussions with the well owner who has contacted the miner regarding a concern and review of baseline data from the well and vicinity to evaluate whether changes may be due to seasonal variations, climate, mining, slurry wall lining or other factors. The report will identify the extent of potential or actual impacts associated with the changes. If the extent of Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 4 groundwater changes due to mining or reclamation activities is determined to be a significant contributing factor that has or may create adverse impacts, the mining associated impacts will be addressed to the satisfaction of the DRMS. Miner will begin implementing one or more mitigation measures if mining and reclamation activity is determined to be a significant factor to groundwater changes requiring mitigation. Mitigation measures may include, but are not limited to: ➢ Placing water in a recharge pond to raise groundwater levels around the well. ➢ Constructing a local clay liner at the edge of the mine Cell (i.e. between the dewatering point and the well) in order to raise water levels on the well side of the liner and mitigate dewatering effects. ➢ Cleaning the well to improve efficiency. ➢ Providing an alternative source of water or purchasing additional water to support historic well use in terms of water quantity and quality. If needed, water quality parameters will be checked in affected wells to ensure alternative sources support historic use. ➢ Modifying a well to operate under lower groundwater conditions. This could include deepening the well or lowering pumps. All work would be done at the miner's expense with the exception of replacing equipment that was non-functional prior to mining. Groundwater Quality Monitoring Plan Since mining operations at the site will take place inside of slurry wall lined cells, except for establishing the Freshwater Pond and Siltation Pond, it is unlikely that these operations will have a negative effect on groundwater quality. To establish pre -mining groundwater quality for the site the permittee will sample MW -2 on the downgradient side of the site and MW -5 on the upgradient side of the site prior to mining. To establish that mining has had no negative affect on water quality in the area, The Operator will sample MW -2 annually during the same quarter as the initial baseline monitoring. The water quality samples will be tested for the analytes listed in Tables 1 through 4 of "The Basic Standards for Ground Water," excluding the radiological section of Table 1. RMCC will notify DRMS within 7 days of receiving a lab report that indicates any of the standards set forth in Tables 1 through 4 have been exceeded. If a lab report indicates an exceedance, a new sample will be taken to verify the exceedance and discount lab contamination. Any water quality lab results will be included in the DRMS annual report for the site. Annual groundwater testing will be conducted for the life of the mine unless the requirement has been reduced or eliminated through the Technical Revision process with the DRMS. Red Tierra Equities, LLC -Section 20 Mine — MLRB 112 Permit Application Exhibit G - 5 Mariah Higgins From: Sent: To: Subject: Attachments: Follow Up Flag: Flag Status: Kyle Regan <kyle@civilresources.com> Thursday, October 27, 2022 11:02 AM Mariah Higgins RE: Red Tierra Equities LLC - Section 20 DRMS 112 File No. M-2022-001 Section 20_ADQ3_Stitched.pdf Follow up Flagged Caution. This email originated from outside of Weld County Government. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi Mariah, Please see the attached DRMS Adequacy Review Response for the Red Tierra Equities, LLC Section 20 DRMS 112 application. Please file this with the application for public review. Thanks! Kyle Regan (m) 408.930.2544 From: Mariah Higgins <mhiggins@weldgov.com> Sent: Tuesday, July 26, 2022 10:14 AM To: Kyle Regan <kyle@civilresources.com> Subject: RE: Red Tierra Equities LLC - Section 20 DRMS 112 File No. M-2022-001 Received. Thank you! Mariah Higgins Deputy Clerk to the Board Clerk to the Board's Office Weld County 1150 O Street Greeley, CO 80631 Tel: (970) 400-4225 Email: mhiggins(d weldgov. com Confidentiality Notice: This electronic transmission and any attached documents or other writings are intended o nly for the person or entity to which it is addressed and may contain information that is privileged, confidential o r otherwise protected from disclosure. If you have received this communication in error, please immediately n otify sender by return e-mail and destroy the communication. Any disclosure, copying, distribution or the Pv6l;G RevJ it/q/22 1 cc: PLCIP/t1P4), Qt,a 0-micti/E-RicK) tI/7iaa 2o22 - 23740 taking of any action concerning the contents of this communication or any attachments by anyone other than the named recipient is strictly prohibited. From: Kyle Regan <kyle@civilresources.com> Sent: Tuesday, July 26, 2022 10:08 AM To: Mariah Higgins <mhiggins@weldgov.com> Subject: Red Tierra Equities LLC - Section 20 DRMS 112 File No. M-2022-001 Caution: This email originated from outside of Weld County Government. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi Mariah, Please see the attached second adequacy review response to be added to the Red Tierra Equities LLC Section 20 DRMS 112 permit application on file with the county for public review. Let me know if you have any questions. Thanks, Kyle Regan 8308 Colorado Blvd Suite 200 Firestone, CO 80504 Phone: (303) 833-1416 x210 www.civilresources.com 6' CIVIL RESWURCES S► ROSS DESK% f WDUK6 Mg 2 CIVIL RESURCES,LLC ENGINEERS & PLANNERS October 27, 2022 Mr. Peter Hays Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 RE: Red Tierra Equities, L.L.C., Section 20 Mine, File No. M-2022-001, 112c Permit Application Adequacy Review 3 Response Dear Mr. Hays: This letter addresses the Adequacy Review letter dated September 12, 2022 regarding the Section 20 Gravel Mine 112 Construction Materials Reclamation Permit Application Package. Responses to your comments follow: The Division of Reclamation, Mining and Safety (Division/DRMS/Office) reviewed the content of the Red Tierra Equities, L.L.C. 112c permit application second adequacy response received on August 25, 2022 for the Section 20 Gravel Mine, File No. M-2022-001 and submits the following comments. The Division is required to issue a recommendation no later than September 22, 2022, therefore a response to the following adequacy review concerns should be submitted to the Division as soon as possible. 1.6 Public Notice 3. Pursuant to Rule 1.6.2(e), please submit proof of the notice to all owners of record of surface and mineral rights of the affected land and the owners of record of all land surface within 200 feet of the boundary of the affected land including all easement holders located on the affected land and within 200 feet of the boundary of the affected land. Proof of notice maybe retum receipts of a Certified Mailing or by proof of personal service. Please provide proof of notice to the owners of record of the surface and mineral rights of the affected land as indicated in Exhibit O. a. CAW Equities, L.L.C. b. Red Tierra Equities, L.L.C. Certified mail receipts have been included with this letter. 6.4.1 Exhibit A - Legal Description 5. The Applicant's response is adequate. 6.4.3 Exhibit C - Pre -Mining and Mining Plan Maps of Affected Land 6. The signed copy of the Exhibit C-2 map omitted several parcel identifications indicated on the previous map in the southeast corner of the site including; • Parcel 105729100002, Owner Strear Farms CO • Parcel 105729000025, Owner Boney MacGillivray LLC. Portions of both parcels appear to be within 200 feet of the proposed affected boundary. Please review the omitted parcel information from the previous map and revise the Exhibit C-2 map accordingly. Revised map included. 8308 COLORADO BLVD • SUITE 2❑❑ • FIRESTONE, COLORADO 80504 • PHONE: 303.833.1416 • FAX: 303.833.285❑ Page 2 Mr. Peter Hays October 27, 2022 Parcel 105721300026 is listed being owned by Leighton Wyscaver on the Exhibit C-2 map. Based on the Exhibit C-3 map, the owner of the parcel is Neil Shimon. Please review the Exhibit C-2 map and revise the map accordingly. Revised map included. Please update the Exhibit C-2 map to include the following noticed property owners: • Donald and Bonnie Deibel • Mack WCR 43 LLC • Zabka Farms The map C-2 has been revised and is included. Zabka Farms is listed as co-owner of Parcel 105720000015 along with CAW Equities, LLC. Mack WCR 43 LLC used to be listed as co-owner of Parcel 105720000019 along with CAW Equities, LLC but has subsequently been removed since the initial submittal of this map. This has been added to the map. Donald and Bonnie Deibel are at Parcel 105721000023 which is located to the southeast of the site and is technically outside of the 200' notification boundary. They have been added to the map. 6.4.4 Exhibit D - Mining Plan 8. The Applicant's response is adequate. 6.4.5 Exhibit E - Reclamation Plan 10. The Applicant's response is adequate. 6.4.6 Exhibit G - Water Information 14. The Applicant's response is adequate. 15. The Gilcrest Area Alluvial Groundwater Model dated August, 2022 is under review by Division staff. Any adequacy concerns related to the report will be sent under separate cover. Response to the Groundwater Model comments have been included with this letter. 6.4.18 Exhibit R - Proof of Filing with County Clerk and Recorder 20. Please provide an affidavit or receipt indicating the date on which the revised application information required to address this adequacy letter was placed with the Weld County Clerk and Recorder for public review, pursuant to Subparagraph 1.6.2(1)(c). Copy of the email to Weld County has been included with this letter. 6.4.19 Exhibit S - Permanent Man-made Structures 24. The Applicant's response is adequate. 6.5 Geotechnical Stability Exhibit 28. Please update the Exhibit C - Mining Plan Maps to indicate the required offsets from the gas lines and the slurry wall based on the stability analysis results. The indicated annotation has been included in the attached Exhibit C-5 and C-7 Maps. The Cell 6 slurry wall alignment has been shifted slightly and the gas lines in cross-section B are closer to the slurry wall but still greater that the 40' required for FOS. 5S. Based on the Exhibit C-7 map, cross-section B should be labeled Section - Cell 6. Please review the Exhibit C-7 map and revise the map accordingly. 6.4.6 Exhibit G - Water Information (New) 30. On Page G-5, the Applicant states to establish pre -mining groundwater quality for the site the permittee will sample MW -2 on the downgradient side of the site prior to mining. Please commit to sampling an upgradient groundwater well prior to mining to establish pre -mining Page 3 Mr. Peter Hays October 27, 2022 groundwater quality for the site. Please identify the upgradient well to be sampled and update Exhibit G accordingly. MW -5 was identified to be sampled prior to mining to establish pre -mining groundwater quality for the site. Please feel free to contact me with any questions or concerns at Kylena,civilresources.com or my cell number 408-930-2544. Regards, CIVIL RESOURCES, LLC Kyle Regan Project Geologist J:IUnited Water 8 San-1411Section 201DRMSICorrespondencelDRMSIAdequacylGroundwater Model Response_10102022.doc PARt:El. 21/51,14:420110.36 c',WIR HS :AVG d, CAME I AWE,. lu1 t99HAW; CAIri£R •IS LANG J CAM( tt'` t. "ic'..'rx.ti;) i J Y.ti nb'Lni. R PNIcf ICI 719O00U1J Ora nS :AND a Ct/71t icc #M4 I1 103410IOOt7a OWNE,. t Cw• u re__ 11 1 1 1 11 111/ / I,E I PARR" AA 105.11 7.I/1000.1 OwNIR Alet 1504 '3A/tie& 1057,7JCLXh1, FxtiCft . I057? 1.00005 LA/1V"R Ret a Mt' PARCEL. /0571740X06 Owe AYYWAM recto a a a a a a a a a a a a a lills a as a a-aa-illie a t.NOIS PERMIT NOUNMOY PARCEL 105720000015 OWI*R :ABAA FARMS AND(AWEQt00ES tic "AAT1'1 C. lr.140QWJ OWNER . 'V ' 1.1j .V/ 2 SUN =MISS= a IS ari al -a -s-a .-a -a S SECTION . MINE a a a a an -a a♦ 'a a al am ass Inn a ~CU LOS 7292000. .1 OWNER tAuR£N SHARP I I' PARCEL 1.)5729.100GJ1 QWWIR. IfRRr IMEDEALAN ARAYft I t75292LA'XI21 OWNER IERRY w;(OEY4N AWES& 103/291000.16 OwA'WR. WAR/ wWOC4pW PARCEL 106120000019 OWNER CAW EQUITIES LLC MO MAC% WCR 4) LLCINCI LONGER LASTED AS OWNER' /WPCEz - 105 74100000 16 CW$ER .4.l it n4Rt.LW a s a a 1 1 a a a IS a a a a a Aik Li "';r;'/.KKQ?J: O WNE R &LANE } MACGILLVR4'w LLi PA.CC£t. 1057: 2XtX.'?6 C *WIN 1h4NC Cc WI a RN.l.fL 1U571000rX 5 — OWNfR Akt%40 PAIRCa 7 a a RARtft '05;19100010000/-/ JWWR bp/ t: C-i.EWlr PARCEL $ 129t00002 OWNER smEMc,vws .t th0 PAAlft 105/IILXXXIJ ' OWNER L'Ot. JW5 SCHN,JI PAA'(:Li 105716o'C J? O MER LEL *cv SieIS FIANCE: 105716JOP:.+?: cJANER CR.6G may'+•'. ?CC OFFSET FROM PERMIT LINE PARCEL . 057.7 20YX?J4 C*PWCR MARL(F KISSt ER PARCft 'OS 72I1000JJ OwnaR NuSSftt A,5Sit I PARCEL l057210'XX12• OrrfR' O4VIO wO(X PFRlcev / PARCEL 06/27Joao 27 OWNER MAR4If 'uSSLIR PARCEL 105121300026 i:IVAER NEIL SHMOV %'ARC& 105711JOOOJI L *WW frOdfWT Ire" R.CE. ,05'21 JV703. *NEN P4011A RA'MXJ1 I PARCEL 705 72 700002 3 OWNER DONALD L IBE L W' BONNIE ROLES DEI&L Mr:PAHLC L,Tao71. 1 tlt '.J' = 51014 Ct tMC K'; 5 taw, P G L1.LMJPJtt3 ALS A ►kOtt iS1t3tlAl IatOtO 4ST AS C€F.VE'J Es,'_O_^41AL0 STiTJ'E Ierams.lai I IN PRr1 know what s below. Call before you ON. toe'Cis LIVIL RES71tiRCES 323 5th STREET P.O. Box 66C FREDERICK, CO 80530 303.633.1416 WWW.CIVILRESOURCES.COM W.CIVI LRESOURCES.COM RED TIERRA EQUITIES,LLC 8101 E PRENTICE AVE 7110 GREENWOOD VILLAGE, CO 80111 )01.771.100S LRI DREW CAMARO SECTION 20 DRMS APPLICATION GILCREST, COLORADO REVISIONS NO DESCRIPTION DATE Lii iIGNED 89 RA DATE 01,01111011 DRAWN IN SCALEPSNOTEO - C..tCtEC 5V BLit AS NOTED AA NO. )19.001.01 I';1'l i, NAME •.DRl' S arggs, affirm. y,DA; PROPERTIES WITHIN 200' EXHIBIT C-2 s �At -+x z IR maBJ1':, 11 OR 3P0 YEARS IIIIAI } • CIVIL RES,URCLS REOTf "EQum'LLC oC O D � O Q Q � U U � w w N U H J BUL sc�t� MINE PLAN AND TIMELINE EXHIBIT C-5 TYPICAL MINE SECRON n....mnekxL E DRMS 112 RECLAMATION PERMIT ERE E MINE PLAN STOCK POI,: EXHIBIT C-6 0+00 0,0 1+00 1+s0 z+00 z+s0 3+00 3,0 SECTION • 0,,1 �surnnax rouo� sroaacE. »ns ac rr December 30, 2021 Mr. Drew Damiano Red Tierra Equities 8301 East Prentice Ave., #120 Greenwood Village, CO 80111 Re: Stability Analysis for the Section 20 Gravel Mine Dear Mr. Damiano: This letter has been prepared to address the Mined Land Reclamation Board (MLRB) Construction Materials Rule 6, Section 4, Subsection 19, Exhibit S - Permanent Man -Made Structures (6.4.19, Exhibit S) for the proposed Section 20 Gravel Mine located northeast of the intersection of State Highway 60 and Weld County Road 42 in Weld County, Colorado. This letter describes the project and slope stability analyses utilized to evaluate the minimum distance between the edge of mining and adjacent structures to avoid damage to the structure. The site is located approximately'/. of a mile west of the town of Gilcrest. More specifically, the site occupies nearly all of Section 20, Township 4 North, Range 66 West of the 6th Principal Meridian. The mine is in an area of irrigated agricultural land with common oil and gas wells and related infrastructure and is bound by Weld County Road (WCR) 42 on the south, State Highway 60 on the west, WCR 44 on the north, and WCR 29 on the east. The mine will consist of eight (8) cells. One (1) of the cells will be wet mined at a mine slope of 2 horizontal to 1 vertical (2h:1 v) and backfilled with the silt byproduct of the wash plant operation. The other seven (7) cells will be lined with slurry walls and will be dry mined at slopes of 1.5h:1. Based on the stability analyses, this report indicates that the setbacks and perimeter slopes in the mining plan are sufficient to protect structures within 200 feet of the permitted mining boundary. Actual setbacks may be greater due to permit limitations, zoning requirements, construction issues, agreements with owners, and extent of economically mineable aggregate or other issues. GEOLOGY The Site is located approximately 21 miles east of the eastem flank of the Rocky Mountain Front Range. Younger sedimentary strata dip eastward off the Pre -Cambrian igneous and metamorphic rocks that form the core of the Front Range into the Denver Structural Basin. The Denver Basin is an asymmetrical downwarp of sedimentary strata with a steeply dipping west limb and a gently dipping east limb. Bedrock does not crop out at the site, however regional geologic mapping of the area (Colton, 1978) indicates the near surface bedrock beneath the site is most likely the Laramie Formation. Colton (1978) describes the Laramie as mostly claystone, shale, sandy shale, and lenticular sandstone. The Lower Laramie is described as sandstone, sandy shale, and claystone with several coal beds. The regional mapping indicates the bedrock is overlain by the Broadway Alluvium. Colton (1978) describes the Broadway as sand and gravel deposited by the South Platte River and its tributaries that is terraced typically lying about 40 feet above major streams. Along the South Platte River, the Broadway is typically on the order of 35 feet thick but can range up to 125 feet thick. GEOTECHNICAL CONDITIONS Based on the site investigations, the natural site stratigraphy generally consists of four main units: 1) Overburden: generally consisting of near surface fine to medium grained sand locally grading to silty or clayey sand; 2) Sand and Gravel: alluvial deposits that underlie the overburden and overlie the bedrock; 3) Mud Lens: silty to clayey sand Mr. Drew Damaniano December 30, 2021 Page 2 commonly interbedded within the sand and gravel unit; and 4) bedrock usually consisting of sandy claystone and sandstone that is commonly weathered in the top 1 foot and is commonly interbedded and interlaminated. Overburden The overburden is typically a fine to medium grained sand that locally grades to silty or clayey sand typically ranging from 0 to 7 feet in thickness. This unit is usually slightly moist to moist, loose to medium dense with the top 6 to 8 inches containing significant organics. Of the overburden samples tested, the range of percent passing the No. 200 sieve ranged from 4.1% to 31.9%. Atterberg Limits testing ranged from granular non -plastic to Liquid Limits of 26 and Plasticity Indices of 9. Sand & Gravel The sand and gravel is present throughout the site locally occurring at the surface, but typically underlying the overburden and overlying the bedrock. This unit typically consists of slightly silty, fine to medium grained sand overlying or grading to a a fine to coarse grained sand and/or gravelly sand. This unit is typically medium dense but locally dense. This unit is commonly fifty (50) feet thick but is locally as thick as eighty-five (85) feet. Mud Lens The mud lens unit is locally interlensed within the sand and gravel unit. This unit typically consists of clayey to silty sand. Thickness varies from one (1) foot to as much as fifteen (15) feet. This unit tends to be thicker on the south part of the site. Bedrock The bedrock encountered in the exploratory borings was generally weathered in the upper foot typically became harder in unweathered zones. The bedrock consisted of sandy claystone. Groundwater Groundwater was encountered in all of the borings at approximately 15 to 25 feet below ground surface. The groundwater levels will vary seasonally and will typically rise during the irrigation season and when recharge is applied. Groundwater will be controlled with the proposed below grade slurry wall and by pumping down the water level on the interior of the slurry wall. After slurry wall construction, groundwater mounding is anticipated on the upgradient (south and southeast) side of the site and a groundwater shadow (deeper water table) is anticipated on the downgradient (north and northwest) side the site. From a geotechnical standpoint, the sand and gravel will form the majority of the mine slopes. These soils are generally strong and stable, particularly when dewatered. With the exception of the silt pond, dry mining is planned in the cells as the slurry wall will control water level in the main cell and mining will be above the water table in the other cell. STRUCTURES WITH 200 FEET OF DISTURBED AREAS The known, permanent, man-made structures within 200 feet of the proposed mine areas that are not owned by the miner are shown on the attached map(Exhibit C-3) STABILITY ANALYSES Division of Reclamation and Mining Safety (DRMS) staff drafted a policy regarding stability analyses of neighboring structures. The draft summarizes adequate factors of safety (FOS) for non -critical and critical structures. The structures around the Section 20 mine are, for the most part, considered critical structures. The FOS are for both static and seismic (from an earthquake) stability analyses. For generalized strength assumptions and critical structures, an FOS of 1.5 is considered sufficient for static conditions and an FOS of 1.3 is considered suitable for seismic conditions. The stability of structures within 200 feet of the proposed mining limits was evaluated at three representative sections under anticipated loading conditions around the perimeter of the site as discussed below. The computer program Mr. Drew Damaniano December 30, 2021 Page 3 XSTABL was used for the analysis. The method for selecting the critical failure surface for each analyzed loading condition is the following. The Modified Bishop's Method of Analysis is used to find the critical failure surface by randomly searching with 20 termination points and 20 initiation points (400 failure circles) with 7 -foot line segments over a broad range of the slope surface and at the structure in question. This procedure is repeated over different initiation and termination locations until the most critical factor of safety failure surface is identified. The range is narrowed and 20 initiation points and 20 termination points (400 failure circles) with 7 -foot line segments for the final run of 400 circles to determine the lowest factor of safety. Therefore, prior to submitting the final stability run, at least 800 failure surfaces were analyzed to determine the lowest factor of safety. Both static stability under anticipated mining conditions and seismic stability under peak ground acceleration loads were performed. Seismic loading was obtained from the U.S.G.S. Unified Hazard Tool attached to this report. Review of the Hazard Tool indicated a maximum horizontal acceleration of 0.082g with a return period of 2,475 years for the site. The three cross section locations were selected and analyzed as described below. ► Section 1: This section is in the northwest corner of the site in an area that will be wet mined prior to being backfilled with silt. This section considers a 50 -foot tall highwall at a point where the mine limit is 40 feet from a gas line. The overburden is modelled at 5 -feet thick and a 2 -foot thick mud lens is modeled within the sand and gravel. This is the most critical section to be wet mined as it marks the point where a tall highwall (deepest bedrock) and closest structure coincide. ► Section 2: This section is the most typical section at the site. This section considers a 50 -foot tall highwall at a point where the mine limit is 30 feet from the slurry wall. The nearest structure is a gas line located 47.6 feet beyond the slurry wall (total distance 77.6 feet from the highwall). The Western Midstream gas line running through Cell 6 may potentially be rerouted around Cell 6 to 20 feet beyond the slurry wall (total distance 50 feet from the highwall. The overburden is modelled at 5 -feet thick and a 5 -foot -thick mud lens is modeled within the sand and gravel. The analysis was run with failure circles starting at 40 -feet from the highwall. Because the FOS meets DRMS standards, structures can be as close as 40 -feet from the highwall. The nearest structure is actually 77.6 -feet from the highwall. ► Section 3: This section is on the southeast part of the site and is the section with the greatest highwall. This section considers an 85 -foot tall highwall at a point where the mine limit is 73 -feet from the slurry wall. The nearest structure is a gas line located 20 feet beyond the slurry wall (total distance 93 -feet from the highwall). The overburden is modelled at 5 -feet thick and a 15 -foot -thick mud lens is modeled within the sand and gravel. The analysis was run with failure circles starting at the slurry wall. Because the FOS at the slurry wall meets DRMS standards and all structures are further from the highwall than the slurry wall, all structures in this area will be stable. MATERIAL PROPERTIES The material index and engineering strengths assumed in this slope stability report are discussed below. Overburden and Mud Lens The strength properties for the in situ silty to clayey sand overburden and mud lens were based on field testing data and on our engineering judgment; the following parameters have been used to model the overburden. Dry Unit Weight (pct) 103 Moist Unit Weight (pct) 114 Saturated Unit Weight (pct) 126 Cohesion C' psf 50 Friction Angle 4,'° 29 Mr. Drew Damaniano December 30, 2021 Page 4 Alluvial Sand and Gravel The sand and gravel is generally a fine to medium -grained sand overlying a fine to coarse grained sand that is typically medium dense and locally gravelly. The alluvial sand and gravel unit was modeled as follows: Dry Unit Weight (pct) Moist Unit Weight (pct) Saturated Unit Weight (pct) Cohesion C' psf Friction Angle 0'. 115 119 129 0 35 Bedrock Bedrock below the alluvium is sandy claystone, sandstone and interlaminated to interbedded claystone and sandstone bedrock. Sandstone is typically stronger than claystone. Claystone is generally a weak bedrock. To be conservative, we modeled the bedrock as claystone. For the claystone bedrock, two potential strength conditions were considered. These strength conditions are referred to as: 1) peak strength, and 2) residual strength. Peak strength is the maximum shear strength the claystone bedrock exhibits. The shear strength is made up of both cohesion (diagenetic bonding) and internal friction. Under short-term conditions for unsheared claystone, peak strength governs behavior. If a sheared surface or sheared zone is present within sandy claystone because of faulting, slippage between beds due to folding, past shrink -swell behavior, stress relief, weathering, or from a landslide, the cohesion along the sheared surface is reduced to zero, and the angle of internal friction is decreased, due to alignment of clay minerals parallel to the shear plane. Under these conditions a claystone exhibits its lowest strength known as residual strength. Residual strength bedrock occurs in discrete zones, parallel with the sheared surface or zone, whereas fully softened strength occurs over a broader area (not used in this modeling). Based on data from site investigations, the residual strength claystone was modeled in a 3/4 -foot thick, weathered layer overlying the peak strength bedrock as follows: Dry Unit Weight (pct) Moist Unit Weight (pct) Saturated Unit Weight (pct) Cohesion C' psf Friction Angle 0'. 116 Peak =126 Residual =110 Peak =135 Residual = 133 Peak =100 Residual = 0 Peak = 29 Residual =18 Soil-Bentonite Slurry Wall The proposed slurry wall will consist of a mix of the overburden clayey to silty sand, alluvial sand, and imported bentonite. The resulting mix will produce a non -Newtonian fluid with some shear strength characteristics based on a reduced friction angle of the overlying overburden. Based on engineering judgment, we modeled the slurry wall as follows: Dry Unit Weight (pct) Moist Unit Weight (pct) Saturated Unit Weight (pct) Cohesion C' psf Friction Angle 0'. NA 112 115 0 0 STABILITY ANALYSES RESULTS The stability analyses assumed the mining will be per the mine plan. The plan includes wet mining in the cell to receive silt and dry mining in the other seven (7) cells as the water level in these cells will be controlled by slurry walls. The mine slopes in the wet mined cell will not exceed 2h:1v. Mine slopes in the slurry wall lined cells will not exceed 1.5h:1v. Setbacks listed in Table 1 (below) indicate the setback from the structure to the mining limits. The setback distance can be increased as needed to address other restrictions. The factor of safety shown below is the minimum factor of safety of the three conditions listed above. Mr. Drew Damaniano December 30, 2021 Page 5 TABLE 1 - SLOPE STABILITY RESULTS AND SETBACKS Section Location Critical Structure Structure Setback From Mine Limit (ft) Static Factor of Safety at Structure Seismic Factor of Safety at Structure (0.082g horizontal) DRMS Draft FOS Requirement Static/Quake 1 Unlined Cell to be wet mined (50', 2h:1 v) Gas Line 40 1.75 1.32 1.5/1.3 2 Lined Cells Dry Mined (50', 1.5h:1v) Gas Line 40 1.60 1.32 1.5/1.3 3 Lined Cells Dry Mined (85', 1.5h:1 v)) Slurry Wall/ Gas Line 73 1.67 1.37 1.5/1.3 CONCLUSIONS Based on the Factors of Safety listed in the table above, the mine will not be a hazard to neighboring structures provided the structure and slurry wall offsets, as well as the perimeter mine slopes, follow the mine plan. LIMITATIONS Our review is based on regional geologic mapping, present mining plans, and in part borehole data by Civil Resources. Stability analyses were performed using typical strength parameters for the various strata in the critical sections. Should the mining plans change or subsurface conditions vary from those portrayed in this letter, we should be contacted in order to re-evaluate the potential affects on permanent man-made structures. Stability analyses were run at the structure in question and were not run on failure surfaces closer to the highwall. Note also that surcharge loads due to temporary material stockpiles and overburden berms were not considered in the analysis. Please call with any questions or comments. Sincerely, Civil Resources, LLC Gary Linden, P.G. Senior Engineering Geologist Attachments: U.S.G.S. Uniform Hazard Tool Earthquake Acceleration XSTABL Model Outputs: Sections 1, 2, and 3 J:1BrannanlGilcrest Geology1Stability AnalysisIStability analysis report - Sec 20.doc EXHIBIT G — WATER INFORMATION This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.4.7 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Locate on the map (Exhibit C) tributary water courses, wells, springs, stock water ponds, reservoirs and ditches The site is 0.4 miles east of the South Platte River. Please refer to Exhibit C for locations of water courses in close proximity to the site, including wells, springs, stock water ponds, reservoirs and ditches. (b) Identify all known aquifers The site is underlain by a shallow alluvial aquifer, typical of its position upgradient of the South Platte River. (c) Show how water from dewatering operations or runoff from disturbed areas, piled material and operating surfaces will be managed to protect against pollution of either surface or groundwater both during and after the operation. Please refer to the Mining Plan Map in Exhibit C-5 of this application. Mine areas will drain internally. Uncontrolled releases of surface water in disturbed areas will not occur. Stormwater collected in the active mine area will be managed through the dewatering system. Dewatering will be accomplished by digging a sump, generally along the base of the mine slope, which will hold a floating pump. The pump will have an HDPE discharge line that will be routed to one of the comingled discharge points located at the site. The pump will be powered by a diesel generator housed in the active mine area. The Operator will apply for and receive a comingled stormwater and process water discharge permit prior to dewatering at the site. (d) Estimate project water requirements including flow rates and annual volumes for the development, mining and reclamation phases of the project. Water needs estimated below provide for sustained production as detailed in the Mining Plan. The Operator will adjust water supplies to account for actual demand, avoid waste, and continuously comply with laws and regulations of the Division of Water Resources and any other water agency having jurisdiction over the operation. Projected Use And Consumption: Annual evaporative depletions will be the evaporation from up to 5000 feet of 4 -foot wide de -watering trench, located inside of the slurry wall. The total area of exposed water is 0.5 acres. The gross annual evaporation at the Section 20 Mine is 42 inches according to NOAA Technical Report NWS 33, Evaporation Atlas for the Contiguous 48 United States. Monthly evaporative losses are determined using percentages specified by the State Engineer's Office for locations below 6,300 feet. The nearest weather station is in Longmont where the average annual precipitation is 15.08. Effective Red Tierra Equities, LLC - section 20 Mine — MLRB 112 Permit Application Exhibit G -1 precipitation, that part of historical precipitation which was consumed by native vegetation on land to be covered by water surface, is conservatively estimated to be 70 percent of the total precipitation. The annual average effective precipitation at the property is estimated to be 9.09 inches. When subtracting the effective precipitation from the gross evaporation yields, the net annual evaporation is 31.44 inches, or 2.68 acre-feet per acre. The Fresh Water Pond is approximately 10 acres and the Siltation Pond will be utilized in 10 acre stages. The approximate acreage of open water surface is 20.5 acres. The annual amount of evaporation from open water surfaces is 54.9 acre-feet. Mining Production & Operations: The Operator expects to extract approximately 2 million tons annually of aggregate material from the site. All water retained in the recovered material will be replaced pursuant to the Substitute Water Supply Plan (SWSP). The total annual amount of water retained in the gravel product from mining activities totals approximately 27.2 acre-feet. The SWSP is renewed annually and will reflect analysis of production and depletion anticipated in each year of operation. In addition, an estimated 4.0 acre-feet of water per year will be used for dust control based (approximately) on 5,900 gallons per day for 5 days a week for 10 months. Annually the total evaporative and operational losses from mining activities (open water surface evaporation, water retained in the aggregate product, dust suppression) totals 86.1 acre-feet of depletion which must be augmented. All depletions were lagged to the Saint Vrain River using the lagging factors approved by the State Engineer pursuant to on -going Substitute Water Supply (SWSP) approvals. (e) Indicate the projected amounts of the water sources to supply project water requirements Replacement Water: The Miner will obtain an approved Substitute Water Supply Plan from the State Engineers office every year, providing annually or more frequently the opportunity to review the sufficiency of water supplies. The SWSP approvals require that the applicant provide a detailed explanation of the mining operations, a quantification of all mining activities and subsequent depletions and all legally available replacement sources. (t) Affirmatively state that the Applicant has acquired or applied fora National Pollutant Discharge Elimination System permit from the Water Quality Control Division The Operator will apply fora National Pollutant Discharge Elimination System (NPDES) permit from the Water Quality Control Division of the Colorado Department of Public Health and Environment prior to discharging water from the site. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 2 Groundwater Sampling and Analysis Plan This information provided in this subsection of Exhibit G is intended to satisfy the requirements outlined in the Groundwater Monitoring and Protection Technical Bulletin dated November 19, 2019: Existing Groundwater Conditions The near surface groundwater is part of an alluvial aquifer in which permeable sand and gravel alluvium overlies relatively impermeable bedrock of either the Fox Hills Sandstone and/or the Laramie Formation. Groundwater, measured in 7 piezometers, occurs at depths usually ranging from 17' to 25' feet below surface with shallower groundwater to the north of the site. The prevailing groundwater flow at the site is to the north reflecting the site topography. Groundwater in the area is tributary to the South Platte River located northwest of the site. Locally the groundwater levels and flow directions are likely influenced by: ➢ The South Platte River is northwest of the site. For most of the year, the river likely acts as a drainage way maintaining groundwater levels at elevations greater than water elevations in the river. In shorter periods of high run off, usually in the spring, river water levels will locally recharge the groundwater table. ➢ The Western Mutual Ditch passes southeast of the site under the intersection of Weld County Road 42 and Weld County Road 29. The ditch may act like a drain during the non - irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. > The Farmers Independent Ditch traverses the southeast corner of the site and bisects Cell 5a and 5b. The ditch may act like a drain during the non -irrigation season maintaining water levels at or above the water levels in the ditch. During the irrigation season, the ditch may serve as a source of recharge to the water table. ➢ There is a pond south of Weld County Road 42. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. ➢ There is a pond north of Weld County Road 44. This pond likely causes elevated groundwater levels at the south of the site during the irrigation season. > Irrigation: The site is located in an area of irrigated cropland. Applied irrigation that is not lost to evaporation and transpiration likely recharges the groundwater. ➢ Alluvial wells: Other than the seven monitoring wells drilled at the site for monitoring groundwater levels, there are also nineteen pumping wells permitted within 600 feet of the mine property. There are seven wells north of the site, two wells east of the site, nine wells south of the site and one well west of the site. If pumping, groundwater will be drawn to these wells. Red Tierra Equities, LLC —Section 20 Mine — MLRB 112 Permit Application Exhibit G - 3 Potential Slurry Wall and Mining Impacts to Local Groundwater Levels For all lined cells, a properly constructed slurry wall will tend to isolate these cells from the surrounding alluvial groundwater table. The liner around these cells could cause "mounding" of groundwater (increase in groundwater elevation) on the upgradient side (southeast) of the lined cells and a potential "shadow effect" (reduction in groundwater level) on the downgradient side (northwest) of the mine. Because the liner will tend to isolate these cells from the surrounding groundwater table, the effects of dewatering when mining lined cells will tend to not extend beyond the liner. Any mounding effect on the upgradient side of the site (south and southwest) is anticipated to be on the order of a few feet or less and will dissipate with distance from the mine. Similarly, shadowing effects will be on the order of a few feet and will dissipate with distance from the mine. The shadowing effects will be minimized by the presence of the South Platte River to the northwest and the Western Mutual Ditch that runs between Cells 5A and 5B and the Farmers Independent Ditch which runs southeast of the site. Dewatering of the unlined cells (Cells 1 and 2) will result in decreases in water levels around these cells. Since there are no wells permitted within 600' of the unlined cells, the effects of dewatering the unlined cells will be minimal. Area Wells A review of the permitted wells on file with the State Engineer's Office (SEO), Division of Water Resources (DWR) indicates that there are nineteen permitted pumping wells within 600 feet of the permit boundary. All of these wells are screened in the alluvium. None of these wells are within 600 feet of the unlined cells (Cells 1 and 2). The well locations and applicants are shown on Figure G-2 attached at the end of this section. Groundwater Level Monitoring and Mitigation Plan Dewatering during mining of Cells 1 and 2 is unlikely to affect any wells in the area. However, if the miner receives a complaint, the following mitigation plan will be implemented. The site monitoring wells will be measured monthly to identify potential changes in alluvial groundwater flow or elevation associated with mining and reclamation activities. Baseline data will be collected prior to dewatering or construction of the slurry walls. Baseline data will be collected from the monitoring program will provide a range of relative water levels associated with pre -mining groundwater conditions. Experience at other mines in similar geologic settings has found that groundwater levels tend to fluctuate being highest in the summer irrigation season and lowest in the winter and early spring. The monthly measurements will be tabulated and included with the DRMS annual report for the site. If, during mining or reclamation, the relative seasonal groundwater elevation at any monitoring wells shows mounding of more than two (2) feet, and the condition was not observed during baseline monitoring, or if the miner receives a complaint from any well owner within 600 feet of the site boundary, then the miner will evaluate the cause and take action within 7 days and notify the DRMS. After the DRMS has been notified, the miner will review the data and available information and submit a report to the DRMS within 30 days. The evaluation will include discussions with the well owner who has contacted the miner regarding a concern and review of baseline data from the well and vicinity to evaluate whether changes may be due to seasonal variations, climate, mining, slurry wall lining or other factors. The report will identify the extent of potential or actual impacts associated with the changes. If the extent of Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 4 groundwater changes due to mining or reclamation activities is determined to be a significant contributing factor that has or may create adverse impacts, the mining associated impacts will be addressed to the satisfaction of the DRMS. Miner will begin implementing one or more mitigation measures if mining and reclamation activity is determined to be a significant factor to groundwater changes requiring mitigation. Mitigation measures may include, but are not limited to: ➢ Placing water in a recharge pond to raise groundwater levels around the well. ➢ Constructing a local clay liner at the edge of the mine Cell (i.e. between the dewatering point and the well) in order to raise water levels on the well side of the liner and mitigate dewatering effects. ➢ Cleaning the well to improve efficiency. > Providing an alternative source of water or purchasing additional water to support historic well use in terms of water quantity and quality. If needed, water quality parameters will be checked in affected wells to ensure alternative sources support historic use. > Modifying a well to operate under lower groundwater conditions. This could include deepening the well or lowering pumps. All work would be done at the miner's expense with the exception of replacing equipment that was non-functional prior to mining. Groundwater Quality Monitoring Plan Since mining operations at the site will take place inside of slurry wall lined cells, except for establishing the Freshwater Pond and Siltation Pond, it is unlikely that these operations will have a negative effect on groundwater quality. To establish pre -mining groundwater quality for the site the permittee will sample MW -2 on the downgradient side of the site and MW -5 on the upgradient side of the site prior to mining. To establish that mining has had no negative affect on water quality in the area, The Operator will sample MW -2 annually during the same quarter as the initial baseline monitoring. The water quality samples will be tested for the analytes listed in Tables 1 through 4 of "The Basic Standards for Ground Water," excluding the radiological section of Table 1. RMCC will notify DRMS within 7 days of receiving a lab report that indicates any of the standards set forth in Tables 1 through 4 have been exceeded. If a lab report indicates an exceedance, a new sample will be taken to verify the exceedance and discount lab contamination. Any water quality lab results will be included in the DRMS annual report for the site. Annual groundwater testing will be conducted for the life of the mine unless the requirement has been reduced or eliminated through the Technical Revision process with the DRMS. Red Tierra Equities, LLC - Section 20 Mine — MLRB 112 Permit Application Exhibit G - 5 Weld County Property Information (970) 400-3650 PROPERTY PORTAL Technical Support (970) 400-4357 Account: R0909301 October 26, 2022 Account Parcel Space R0909301 105720000019 Agricultural Legal Assessed Value 38,773 I 10,240 PT SE4 20-4-66 LOT B REC EXEMPT RE -3000 (2.08R1.27D) Subdivision Account Owner Name Address GREELEY RURAL i R0909301 CAW EQUITIES LLC 8301 E PRENTICE AVE STE 100 GREENWOOD VILLAGE, CO 801112904 Reception Rec Date Type Grantor Grantee Doc Fee Sale Date Sale Price MC CLELLAN MC CLELLAN 2427367 04-21-1995 QCN GEORGE B GEORGE B 0.00 02-15-1995 0 JR & BETTY JR & BETTY J 2842709 04-24-2001 RE RECORDED EXEMPTION RE -3000 0.00 0 2842709 04-24-2001 RE RE -3000 RE -3000 0.00 04-24-2001 0 MCCLELLAN MCCLELLAN 3720483 09-23-2010 QCN GEORGE B BETTY J 0.00 09-22-2010 0 JR TRUST MCCLELLAN MCCLELLAN 3883486 10-24-2012 TRUN GEORGE B FAMILY 0.00 10-19-2012 0 TRUST TRUST MCCLELLAN JACK R DYNASTY TRUST; 4199315 04-28-2016 QCN ARESCO JEAN MARIE MACK WCR 43 LLC 0.00 04-27-2016 0 DYNASTY TRUST; KELLER R et al. 4643529 10-23-2020 SWD MACK WCR CAW EQUITIES 120.80 10-22-2020 1,208,000 43 LLC LLC 4809170 03-10-2022 SURV SURVEY SURVEY 0.00 10-05-2020 0 *If the hyperlink for the reception number does not work, try a manual search in the Clerk and Recorder records. Use the Grantor or Grantee in your search. Copyright © 2022 Weld County, Colorado. All rights reserved. Privacy Policy & Disclaimer I Accessibility Information August 1st, 2022 Board of County Commissioners 915 Tenth Street P. O. Box 758 Greeley CO 80632 VIA: Email RECEIVED AUG 01 2022 WELD COUNTY COMMISSIONERS RE: Division of Reclamation Mining and Safety, Mine Land Reclamation Board (111) Special Operation Reclamation Permit Application, Weld County, Colorado; Section 20 Gravel Mine Dear Board: Jalisco International, Inc. is applying fora MLRB permit amendment to mine sand at the project site for a Colorado Department of Transportation roadway project at Weld County Road 44 and Highway 85. The mine site is located on the east side of Highway 60 about one half mile west of the Town Of Gilcrest. More specifically, the site is within parts of Section 20, Township 4 North, Range 66 West of the 6th Principal Meridian. The mine is in an area of irrigated agricultural land with common oil and gas wells and related infrastructure and is east of Highway 60, north of Weld County Road 42, south of Weld County Road 44 and west of Weld County Road 29. As required by the DRMS regulations, we have enclosed the following the full Construction Material Special (111) Operation Reclamation Permit Application Package for your review. If you have any questions, please feel free to contact me at 303-833-1416 ext. 210 or email me at Kyle@civilresources.com. Sincerely, CIVIL RESOURCES, LLC Kyle Regan Project Geologist J:1United Water & San-141\Sedan 201Jalisco Project Permit App\Notices\NOTICE Cltr Cnty Cmmsrs.doc Pub 1, C Rev". et.) cc : PL(Tr/MM), (mtIGH/ER /GK) V17 422. V12/22 2022-2370 August 1st, 2022 Clerk to the Board of Weld County Commissioners 915 Tenth Street, Rm 317 Greeley, CO 80632 RE: Section 20 Gravel Special (111) Operation Reclamation Permit Application Dear Clerk to the Board: RECEIVED AUG 01 2022 WELD COUNTY COMMISSIONERS As a requirement of the Division of Reclamation Mining and Safety (DRMS), the complete Section 20 Gravel Mine Special (111) Operation Reclamation Permit Application Package must be on file at the County Clerk's Office and be available for public viewing. A copy of the complete application on behalf of Jalisco International, Inc is attached. As always, thank you for your assistance. Sincerely, Civil Resources, LLC Kyle Regan Project Geologist J:IUnited Water & San -141 \Section 201DRMS1NoticeslProof Of Mailingletter to cler_signature regted.doc COLORADO DIVISION OF RECLAMATION, MINING, AND SAFETY: CONSTRUCTION MATERIALS SPECIAL 11'I RECLAMATION PERMIT PREPARED FOR: Jalisco International, Inc. 6663 Colorado Blvd. Commerce City, CO 80022 PREPARED BY: Civil Resources, LLC 8308 Colorado Blvd, Suite 200 Firestone, CO 80501 303.833.1416 DATE PREPARED: July 2022 CIVIL RES URCES,LLC ENGINEERS & PLANNI=RS STATE OF WLO?ADO DIVISION OF RECLAMATION, MINING AND SAFETY Department of Natural Resources 1313 Sherman St, Room 215 Denver, Colorado 80203 Phone: (303) 86 3567 FAX: (303) 832-3106 CONSTRUCTION MATERIALS SPECIAL (111) OPERATION RECLAMATION P.ER.MIT APPLICATION FORM COLORADO D1VlSiON 0I RECLAMATION MINING SAFETY The application for a Construction Materials Special 111 Operation Reclamation Permit contains four major parts: (1) the application form; (2) Exhibits A -L, Addendum I , and any sections of Exhibit 6.5 (Geotechnical Stability Exhibit), as required by the Office, and outlined in Rules 6.1, 6.2, 6.3, 6.5, and 116.2(1)(b); (3) the application fee; (4) the Performance Warranty and if required a FinancialWarranty_ When you submit your application, be sure to include one (1) completed., Signed and notarized. ORIGINAL and one (1) copy of the completed application form, two (2) copies of Exhibits A -L,, Addendum 1, appropriate sections of Exhibit 6.5 (Geotechnical Stability Exhibit), as required, a check for the application fee described under (4) below, and the fully executed Performance Warranty and Financial Warranty, if required. Exhibits should NOT be bound or in 3 -ring binders; maps should be folded to 8 2" X 117 or 8 2" .X 14" size. To expedite processing, please provide the information in the format and order described in this form. GENERAL OPERATION INFORMATION Type or print clearly, in the space provided, all information described below 1, Applicant/operator or company name (name tot be used on the permit): Jalisco International, Inc. 1.1 Type of organization (corporation, partnership, etc.): Corporation 2.Operation name (pit, mine or site name): Section 20 Mine Permitted acreage: 4. New Application 5. Prin i a.ry commoditie(s) to be mined; Overburden, Sand and Gravel 6.. Name of owner to the surface of affected land: 7. Name of owner to the subsurface rights of affected land: CAW Equities, L.L.C. 29.73 Permitted Acres $898.00 Application Fee Red Tierra Equities, L.L.C. 8. Type of min.in2 operation: 1 I Surface Underground. I. -situ 9. Location information: The center of the area where the majority of mining will occur: ' OU r\1, Weld PRINCIPAL MERIDIAN (check one): SECTION (write number). TOWNSHIP (write number and check direction): RANGE (write number and check direction): QUARTER SECTION (check one): QUARTER/QUARTER SECTION (check one): 6th (Colorado) 20 T 4 R 66 HNEL 10th (New Mexico) _ 7H North I East I NW NE MV RI r ElSE F SE Ute r SW SW GENERAL DESCRIPTION: (the number of miles and direction from the nearest town and the approximate elevation): Approximately 1/2 miles to the Town of Gilcrest at elevation 4746' Office o Mined Land Reclamation Denver • Grand Junction * Durango Office of Active and Inactive Mines 10. Primary Mine Entrance Location (report in either Latitude/Longitude OR UTI` : L atitude/Longitude: Example: (N) 39° 44' 12.98" (W) 104° 59' 3.87" L atitude (N) : deg 104 48 12 47 Longitude (W : deg min sec . (7 decimal places) 40 OR Example: (N) (W) 39136910 -104.98449° min 18 sec 15 65 (P) decimal places) Latitude (N) (5 decimal places) L ongitude(W) (5 decimal places) OR Universal Tranverse Mercator (UTI D Example: 201336.3 E NAD27 Zone 13 4398351.2 N NAD83 ad 83 UTM Datum (speedy NAD27, or WOS 84) Zone Easting ti.. Northing 11. Primary Future (Post -mining) Land Use (check only one): ✓ r Cropland(CR) Rangeland(RL) Residential(RS) Pastureland(PL) Forestry(FR) Recreation(RC) Developed Water Resources(WR) Primary Present Land Use (check only one): ✓ n Cropland(CR) Rana eland(RL) ) Residential(RS) Pastureland(PL) Forestry(FR) Recreation(RC) Developed Water Resources(WR) 13. Estimated Beginning Date of Contract: 13.1 Estimated completion date of contract: r 12 General Agriculture(GA) Wildlife Habitat(WL) Industrial... Commercial(IC) Solid Waste Disposal(WD) General Agriculture(GA) Wildlife Habitat(WL) Industrial/Commercial(IC) Mining(MN) August 2022 December 2023 3 15. Correspondence Information: APPLICANT/OPERATOR (name, address, and phone of name to be used on permit) Contact's Name: Richard Ledezma Title: President Company Name: Street/P.O. Box: City: State: CO Zip Code: 80022 Jalisco International, Inc. 6663 Colorado Blvd Commerce City P.O. Box: Telephone Number: (303 ) - 287.8905 Fax Number: ( PERMITTING CONTACT (if different from applicant/operator above) Contact's Name: Kyle Regan Company Name: Street/P.O. Box: City: State: Civil Resources, LLC Title: Project Geologist 8308 Colorado Blvd Firestone P.O. Box: CO Zip Code: 80504 Telephone Number: (408 ) - 930-2544 Fax Number: ( ) - INSPECTION CONTACT Contact's Name: Company Name: Street/P.O. Box: City: State: Telephone Number: Fax Number: Pete Kubiak Title: Senior Project Manager Jalisco I nternation, Inc. 6663 Colorado Blvd P.O. Box: Commerce City CO Zip Code: 80022 (303 ) _ 287.8905 ( ) - CC: STATE OR FEDERAL LANDOWNER (if any) Agency: Street: City: State: Telephone Number: Zip Code: CC: STATE OR FEDERAL LANDOWNER (if any) Agency: Street: City: State: Telephone Number: Zip Code: ( ) 4 14. Maps & Exhibits: Submit two (2) complete, unbound copies of the following application exhibits: 6.3.1 6.3.2 6.3.2 6.3.4 6.3.5 6.3.6 6.3,7 6.3.8 6.3.9 6.3.10 6.3,11 6.3.12 1.6.2(1)(b) 6.5 EXHIBIT A - Legal Description and Location Map EXHIBIT B - Site Description EXHIBIT C - Mining Plan EXHIBIT D - Reclamation Plan EXHIBIT E - Maps, to include the location of any recorded easements EXHIBIT F - List of Other Permits and Licenses Required EXHIBIT & - Source of Legal Right -to -Enter EXHIBIT H - Municipalities Within a Two -mite Radius EXHIBIT I - Proof of Filing with County Clerk EXHIBIT J - Proof of Mailing Notices of Permit Application EXHIBIT K - Terms of Governmental Contract EXHIBIT L - Permanent Man-made Structures ADDENDUM 1 - Notice Requirements Geoteehnical Stability Exhibit (as required) Responsibilities as a Permittee: Upon application approval and permit issuance, this application becomes a legally binding document. Therefore, there are a number of important requirements which you, as a permittee, should fully understand. These requirements are listed below. Please read and initial each requirement, in the space provided, to acknowledge that you understand your obligations. If you do not understand these obligations please contact this Office for a full explanation, I I. Your obligation to reclaim the site is not limited to the amount of the financial warranty. You assume legal liability for all reasonable expenses which the Board or the Office may incur to reclaim the affected lands associated with your mining operation in the event your permit is revoked and financial warranty is forfeited; 2. The Board may suspend or revoke this permit, or assess a civil penalty, upon a finding that the perinittee violated the terms or conditions of this permit, the Act, the Mineral Rules and Regulations, or that information contained in the application or your permit misrepresent important material facts; 3. If your mining and reclamation operations affect areas beyond the boundaries of an approved permit boundary, substantial civil penalties, to you as permtttee can result; 4. Any modification to the approved mining and reclamation plan from those described in your approved application requires you to submit a new permit application and obtain approval from the Board or Office; 5. It is your responsibility to notify the Office of any changes inyour address or phone number; 6. Upon permit issuance and prior to beginning on -site mining activity, you must post a sign at the entrance of the mine site, which shall be clearly visible from the access road, with the following information (Rule 3.1.12): a. the name of the operator; b. a statement that a reclamation permit for the operation has been issued by the Colorado Mined Land Reclamation Board; and, c. the permit number. 5 - 7. The boundaries of the permit boundary area must be marked by monuments or other markers that are clearly visible and adequate to delineate such boundaries prior to site disturbance; 8. It is a provision of this permit that the operations svill be conducted in accordance with the terms and conditions listed in your application, as well as with the provisions of the Act and the Mineral Rules and Regulations in effect at the time the permit is issued. 9. Annually, on the anniversary date of permit issuance, you must submit an annual fee ($504), and an annual report which includes a map describing the acreage affected and the acreage reclaimed to date (if there are changes from the previous year), any monitoring required by the Reclamation Plan to be submitted annually on the anniversary date of the permit approval. Annual fees are for the previous year a permit is held. For example, a permit with the anniversary date of July 1, 1995, the annual fee is for the period of July 1, 1994 through June 30, 1995. Failure to submit your annual fee and report by the permit anniversary date may result in a civil penalty, revocation of your permit, and forfeiture of your financial warranty. It is your responsibility, as an operator, to continue to pay your annual fee to the Office until the Board releases you from your total reclamation responsibility. NOTE TO COMMENTORS/OBJECTORS: . / BJE TO : It is likely there will be additions, changes, and deletions to this document prior to final decision by the Office. Therefore, if you have any comments or concerns you must contact the applicant or the Office prior to the decision date so that you will know what changes may have been made to the application document. The Office is not allowed to consider comments, unless they are written, and received prior to the end of the public comment period. You should contact the applicant for the final date of the public comment period. If you have questions about the Mined Land Reclamation Board and Office's review and decision or appeals process, you may contact the Office at (303) 866-3567. Certification: cation: As an authorized representative of the applicant, .1 hereby certify that the operation described has met the minimum requirements of the following terms and conditions: l ►.l.l necessary approvals from local government have been applied for (Section 34-32.5-111(i)(a)(1 )B; 2. This entire mining operation will not affect more than 30 acres; 3. This mining operation will not adversely affect the stability of any significant, valuable and permanent man-made structure(s) locatedwithin do hundred (200) feet of the affected lands. (However, where there is an agreement between the applicant/operator and the persons having an interest in the structure that damage to the structure is to be compensated for by the applicant/operator (Section 34-32.5-11.5(4)(c), C.R.S. 1984, as amended), then mi,ning may occur within 200 feet. Proof of an agreement must be submitted to the Office prior to the decision date.) 4,. No mining operation will be located on lands where such operations are prohibited by law (Section 34-32.5-115(4)( , C.R.S. 1984, as amended); 5. As the applicant/operator,1 do not have any mining/exploration operations in this state of Colorado currently in violation of the provisions of the Colorado Land Reclamation Act for the Extraction of Construction Materials (Section 34-32.5-120, C.R.S. 1984, as amended) as determined through a Board finding. 6. I understand that statements in the application are being made under penalty of perjury and that false statements made herein are punishable as a Class 1 misdemeanor pursuant to Section 18-8-503, C.R.S. 1984, as amended. This form has been approved by the Alined Land Reclamation Board pursuant to section 34-32.5-i I i, C R. S., of the Colorado Lurid ec anritlorr /let for the Extraction of onstructiorn Materials. Any alteration or mudr' icati fehiti nn shall result in voiding any permit it issued on the altered or modifiedf form and subject the operator to cease an T� 9 ?f ivil penalties for operating without apermritpursuant to section 34J2.5-123, H.S. 41/4' s dia r O a .. Iv . nod and dated this 1st day of August 2022 c *4 SEA 3 .� 1985 85 ;' " i if cor-ptior.` 'a 1 � ) be . etre * Nk.' I Corporate Sc.ry or Equ ` ,lent Towniri unty Clerk Jalisco International, Inc. r3 President Title: State d Colorado County of Ad s ) ss. B The foregoing rn torment was acknowledged before me this 1st day of August gust f 0 2 Richard Lodezeta. as President of Jalisco International, Inc. KACIE SANCHEZ CASTANON NOTARY PUBLIC STATE OF COLORADO NOTARY ID 2022 267 MY COMMISSION EXPIRES JANUARY 04 2026 y li My Commissi SIGNATURES MUST BE IN BLUE INK Sink Opt 7 OUe ExHIBIT A EXHIBIT A - LEGAL DESCRIPTION This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.1 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: LEGAL DESCRIPTION PARCEL 1: A PORTION OF THE NORTHWEST QUARTER (NW114) OF SECTION TWENTY (20) TOWNSHIP FOUR (4) NORTH, RANGE SIXTY -51X (66) WEST OF THE 6TH P.M., COUNTY OF WELD, STATE OF COLORADO PROPOSED CENTER AREA WHERE THE MAJORITY OF MINING WILL OCCUR IS IN THE SOUTHEAST QUARTER (SF1/4) OF THE NORTHWEST QUARTER (NIW1/4) OF SECTION TWENTY (20) TOWNSHIP FOUR (4) NORTH, RANGE SIXTY-SIX (66) WEST OF THE 6TH P.M., COUNTY OF WELD, STATE OF COLORADO MINING PERMIT BOUNDARY See Exhibit A Map MINING ENTRANCE UTM Datum NAD 83 Zone 13 Easting: 516701/54 Northing: 4461556.18 Section 20- Gravel Mine — MLRB 111 Permit Application Exhibit A -1 EXHIBIT B USDA United States a Department of Agriculture NKS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Weld County, Colorad Southern Part August 31, 2021 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.goviwpsi portal/nres/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.govllocator/app?agency=arcs) or your NROS State Soil Scientist (http://www.nres.usda.govfwpslportal/nres/detaillsoils/contactusl? aid=nres 14.2 p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other f=ederal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (N RCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the N RCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface 2 How Soil Surveys Are Made 5 Soil Map 8 Soil Map 9 Legend 10 Map Unit Legend 11 Map Unit Descriptions 11 Weld County, Colorado, Southern Part 13 1 Altvan loam, 0 to 1 percent slopes 13 11 Bresser sandy loam, 0 to 3 percent slopes 14 29—Julesburg sandy loam, 0 to 1 percent slopes 15 30—Julesburg sandy loam, 1 to 3 percent slopes 16 39 —Nunn loam, 0 to 1 percent slopes 18 76 —Vona sandy loam, 1 to 3 percent slopes 19 References 21 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil -vegetation -landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 Custom Soil Resource Report scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil -landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil -landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field -observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and 6 Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 Custom Soil Resource Report MAP LEGEND Area of Interest (01) Area of Interest (AO!) Soils pabo • Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features a - Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide orSlip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways sozossis US Routes Major Roads Local Roads Backgr a nd Aerial Photography MAP INFORMATION The soil surveys that comprise your AO1 were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Weld County, Colorado, Southern Part Survey Area Data: Version 19, Jun 5, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 19, 2018 Aug 10,2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 10 Custom Soil Resource Report Map Unit Legend Map Unit Symbol Map Unit Name Acres in Aol Percent of AOI 1 Altvan slopes loam, 0 to 1 percent 14.0 1.8% 11 Bresser sandy percent slopes loam, 0 to 3 23.6 3.0% 29 Julesburg sandy percent slopes loam, o to 1 613.0 77.5% 30 Ju lesbu rg sandy percent slopes loam, 41 to 3 123.7 15.6% 39 Nunn slopes loam, 0 to 1 percent 13.9 1.8% 76 Vona sandy loam, percent slopes 1 to 3 2.9 0.4% Totals for Area of Interest 791.0 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it 11 Custom Soil Resource Report was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha -Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 12 Custom Soil Resource Report Weld County, Colorado, Southern Part 1 Altvan loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 361j Elevation: 4,500 to 41900 feet Mean annual precipitation: 14 to 16 inches Mean annual air temperature: 46 to 48 degrees F Frost -free period: 130 to 150 days Farmland classification: Not prime farmland Map Unit Composition Altvan and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the rcaunit. Description of Altvan Setting Landform: Terraces Down -slope shape: Linear Across -slope shape: Linear Parent material: old alluvium Typical profile I - 0 to 10 inches: loam H2 - 10 to 25 inches: clay loam H3 - 25 to 60 inches: gravelly sand Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class. Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 2.00 inthr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None calcium carbonate, maximum content: 5 percent Available water supply, 0 to 60 inches: Low (about 5.7 inches) Interpretive groups Land capability classification (irrigated): 3s Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Minor Components Cascajo Percent of map unit: 9 percent Hydric soil rating: No 13 Custom Soil Resource Report Aquic haplustolls Percent of map unit: 1 percent Landform: Swales Hydric soil rating: Yes 11 Breer sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2swl0 Elevation: 4,050 to 6,800 feet Mean annual precipitation: 12 to 18 inches Mean annual air temperature: 45 to 55 degrees F Frost -free period: 135 to 190 days Farmland classification: Prime farmland if irrigated and the product of I (soil erodibility) x C (climate factor) does not exceed 60 Map Unit Composition Dresser and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Bresser Setting Landform: Drainageways Landform position (three-dimensional): Tread Down -slope shape: Linear Across -slope shape: Linear Parent material: Coarse sandy alluvium derived from igneous, metamorphic and sedimentary rock Typical profile Ap - 0 to 9 inches: sandy loam Bt - 9 to 25 inches: sandy clay loam BC - 25 to 30 inches: sandy loam C - 30 to 79 inches: loamy sand Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (sat): Moderately high to high (0.60 to 2.00 in/I-1r) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of pending: None Calcium carbonate, maximum content: 10 percent Maximum salinity: Nonsaline (0.0 to 0.1 mmhoslcm) Available water supply, 0 to 60 inches: Low (about 5.8 inches) 14 Custom Soil Resource Report Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4c Hydrologic Soil Group: B Ecological site: R067BY024CO - Sandy Plains Hydric soil rating: No Minor Components Truckton Percent of map unit: 5 percent Landform: Drainageways Landform position (three-dimensional1) Tread Down -slope shape: Linear Across -slope shape: Linear Ecological site: R067BY024CO - Sandy Plains Hydric soil rating: No Vona Percent of map unit: 5 percent Landform: Stream terraces Landform position (three-dimensional): Tread Down -slope shape: Linear Across -slope shape: Linear Ecological site: R067BY024CO - Sandy Plains Hydric soil rating: No 29—Julesburg sandy loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 3626 Elevation: 4,700 to 4,800 feet Mean annual precipitation: 15 to 19 inches Mean annual air temperature: 48 to 52 degrees F Frost -free period: 145 to 155 days Farmland classification: Prime farmland if irrigated and the product of I (soil erodibility) x C (climate factor) does not exceed 60 Map Unit Composition Julesburg and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Julesburg Setting Landform: Terraces Down -slope shape: Linear Across -slope shape: Linear Parent material: South plane river alluvium 15 Custom Soil Resource Report Typical profile Hi - 0 to 12 inches: sandy loam H2 - 12 to 27 inches: sandy loam H - 27to 60inures: sand Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Very low Capacity of the most limitin ► layer to transmit water (sat) High (2.00 to 6.00 inihr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water supply, 0 to 60 inches: Moderate (about 6.5 inches) Interpretive groups Land capability classification (irrigated): 2s Land capability classification (non irrigated): 3e Hydrologic Soil Group: Ecological site: R067BY024CO - Sandy Plains Hydric soil rating: No Minor Components Valent Percent of map unit: 4 percent Hydric soil rating: No Remmit Percent of map unit: 4 percent Hydric soil rating: No Edgar Percent of map unit: 4 percent Hydric soil rating: No Vona Percent of map unit: 3 percent Hydric soil rating: No 30—Julesburg ulesburg sandy loam, to 3 percent slopes Map Unit Setting National map unit symbol: 2tIpz Elevation: 4,200 to 4,320 feet Mean annual precipitation: 15 to 20 inches Mean annual air temperature: 46 to 52 degrees F Frost -free period: 144 to 163 days Custom Soil Resource Report Farmland classification: Prime farmland if irrigated and the product of I (soil erodibility) x C (climate factor) does not exceed 60 Map Unit Composition Juiesburg and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Julesburg Setting Landform: I nterfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Linear Across -slope shape: Linear Parent material: Eolian sands Typical profile A - g to 5 inches: sandy loam BA - 5 to 12 inches: sandy loam Bt1 - 12 to 30 inches: sandy loam Bt2 - 30 to 39 inches: sandy loam C - 39 to 80 inches: loamy sand Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Very low Capacity of the most limiting layer to transmit water (sat): High (2.00 to 6.00 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Maximum salinity: Nonsaline to very slightly saline (0.1 to 2.0 mmhoslcm) Available water supply, 0 to 60 inches: Low (about 5.9 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification fnonirrigated,): 4s Hydrologic Sod Group: Ecological site: R07 Y111 KS - Sandy Plains Hydric soil rating: No Minor Components Haxtun Pe rcen t of map unit: 5 percent Landforrr: Interfluves, drainageways Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Linear Across -slope shape: Concave Ecological site: R07 XY111 KS - Sandy Plains Hydric soil rating: No Custom Soil Resource Report Valent Percent of map unit 5 percent Landform: Interflcves Landform position (three-dimensional): Interfluye Down -slope shape: Linear Across -slope shape: Linear Ecological site: Ro72 Y199K - Rolling Sands Hydric soil rating: No Manter nter Pe rcen t of map unit: 5 percent Landform: I nterfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): I nterflcye Down -slope shape: Linear Across -slope shape: Linear Ecological site: RO72 Y111 - Sandy Plains Hydric soil rating: No 39 Nunn loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2tl n3 Elevation: 3,900 to 6,250 feet Mean annual precipitation: 13 to 16 inches Mean annual air temperature: 46 to 54 degrees F Frost -free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform: Terraces Landform position (three-dimensional): Tread Down -slope shape: Linear Across -slope shape: Linear Parent material: Pleistocene aged alluvium and/or eolian deposits Typical profile Ap-0to 6inches: loam Bt1 - 6 to 10 inches: clay loam Bt2 - 10 to 26 inches: clay loam Btk - 26 to 31 inches: clay loam Bkl - 31 to 47 inches: loam Bk2 - 47 to 80 inches: loam 18 Custom Soil Resource Report Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat)Moderately low to moderately high (0.06 to 0.20 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 7 percent Maximum salinity: Nonsaline (0.1 to 1.0 mmhoslcm) Sodium adsorption ratio, maximum: 0.5 Available water supply, 0 to 60 inches: High (about 9.2 inches) Interpretive groups Land capability classification ('irrigated): 3e Land capability classification (nonirrigated): 4c Hydrologic Soil Group: Ecological site: Ro 7BY002CO - Loamy Plains Hydric soil rating: No Minor Components Haverson, rarely► flooded Percent of map unit: 10 percent Landform: Drainageways Down -slope shape: Linear Across -slope shape: Concave Ecological site: R067BY036CO - Overflow Hydric soil rating: No Heldt Percent of map unit: 5 percent Landform: Terraces Landform position (three-dimensional) Tread Down -slope shape: Linear Across -slope shape: Linear Ecological site: R067 BY042CO - Clayey Plains Hydric soil rating: No 76 Vona sandy loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: 363w Elevation: 4,600 to 5,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 55 degrees F Frost -free period: 130 to 160 days Farmland classification: Farmland of statewide importance 19 Custom Soil Resource Report Map Unit Composition Vona and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Vona Setting Landform: Terraces, plains Down -slope shape: Linear Across -slope shape: Linear Parent material: Alluvium and/or eolian deposits Typical profile H9 - 0 to 6 inches: sandy loam H2 - 6 to 28 inches: fine sandy loam H3 - 28 to 60 inches: sandy loam Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Very low Capacity of the most limiting layer to transmit water'Ksat,): High (1.98 to 6.00 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to slightly saline (0.0 to 4.0 mmhoslcm) Available water supply, 0 to 60 inches: Moderate (about 6.8 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: A Ecological site: R067BY024CO 0 4CO - Sandy Plains Hydric soil rating: No Minor Components Remmit Percent of map unit: 9 percent Hydric soil rating: No Olney, Percent of map unit: 3 percent Hydric soil rating: No Julesburg Percent of map unit: 3 percent Hydric soil rating: No References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wpsiportali nresldetaillnationallsoilst'acid=nres142p2_U 54262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nres.usda.gov/wpsiportallnresldetail/national/soils/ ?cid=nres142p2_0 77 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.goviwpsiportalinrcsidetailinationalisoilsncid=nrcs142p2 053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.goviwpsiportalinrcsidetailisoilsi home/?cid=nresl 42p2_OS3374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http:IIwww.nres.usda.goviwpslportallnresl {detail/national/I and use/rang epasture/?cid=stelprdb104 0► 4 21 Custom Soil Resource Report United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430 -VI. http://www.nres.usda.gov/wps/portal/ nres/detail/soilslscientists/?cid=nres14 'p _054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. J.S. Department of Agriculture Handbook 296. http://www.nres.usda.gov/wpslportal/arcs/detail/nationallsoiIs!? cid =nres 142 p2_0 53624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/InternetiFSE D U M E NTS/n res 142p _052290. pd f 22 EXHIBIT J- Vegetation Information Site Description A Savage and Savage botanist and plant ecologist conducted an on -site vegetation assessment for the proposed Red Tierra Equities project site on October 26, 2021. The project site is comprised of an approximately 650 acre site within Section 20 of Township 4 North, Range 66 West of the 6t1i PM, Weld County, Colorado. The center of the project site is located at 40.297143' latitude and -104.8014700 longitude. The property is located west of Gilcrest, Colorado between Colorado Highway 60 on the west. Weld County Road 44 on the north, Weld County Road 29 on the east, and Weld County Road 42 on the south (Figure 1.). The project site is accessed from any of the above roads. Weather during the site investigation was warm, dry and clear with a temperature in the mid -60's (°F). The topography of the site is dominated by the primary alluvial terrace of the South Platte River. The elevation of the center of the project area is 4760 feet and slopes gently to the west toward the river. The soils that dominate the site are formed from alluvium, with the predominant soils being sandy barns (Julesburg and Bresser map units) and loam (Nunn map unit) and are underlain by aggregate with varying groundwater levels. The significant hydrologic feature near the site is the South Platte River. The project site has been developed for irrigated agriculture, oil and gas production, and a solar energy array, with very little native vegetation remaining. The project site has no tree canopy or shrub understory, with the only trees and shrubs located within the yards of homesteads at the edge of the agricultural fields. Agriculture within the project site is irrigated by pivot and flood irrigation methods. Only one vegetation community or type is found within the proposed Red Tierra Equity project site: irrigated agriculture, either flood or pivot -irrigated. Vegetation Community Irrigated Agriculture Agricultural fields within the project area were in various states of production during the on -site evaluation. The majority of the fields had been harvested for the season, and disked or tilled and left fallow, or replanted. The exception was the northwest quarter section which has been planted to specialty lettuce crops and was in the process of being harvested b variety (Figure 2.). t Several fields within the project site have been planted to winter wheat. and germination of the crop was noted (Figure 3.) . Additional fields were noted to have been planted to corn during the 2021 season which has been harvested and the fields disked and tilled prior to anticipated planting. Several irrigation tailwater ponds are located within the project area. These ponds did not contain any native vegetation communities. One irrigation canal and a number of secondary irrigation ditches traverse the project site. None contain areas of native vegetation. Exhibit J Page 1 The Natural Resource Conservation Service soil survey reports yields for common crops (1980) as follows for the Julesburg, Bresser, and Nunn map units; alfalfa hay (5.5 tons/acre), sugar beets (23-24 tons/acre), corn (150-180 bushels/acre), corn silage (33-35 tons/acre), dry pinto beans (2400-2700 pounds/acre), onions (525-550 sacks/acre), and potatoes (325-350 hundredweight/acre). Threatened and Endangered Species and Critical Habitat Potential habitat for the Ute ladies' -tresses orchid (Spiranthes diluvialis), the sole threatened or endangered plant species known in the area, is not present within the project site. There are no subirrigated hay fields with native vegetation containing typical plant associates of the orchid. The current proposed project site does not include disturbance to Ute ladies' -tresses orchid potential critical habitat; therefore, no further evaluation was undertaken. Exhibit J Page 2 Figure 1. Red Tierra Equity Project Site -Vegetation Types and Land Uses Land Us Pin Ag Agriculture ''' , O/G Oil & Sas Production 0 S Solar Energy Array Vegetation Types Cr Annual crops - f6. • ae ^ _ air a _ a• I �• i. _ _tri .— saisizr tip } f '-'!---‘e. Cn� - > - ° � -° J a 1- y r •if y.f- n ra- I — Se - a r eye- Iii ate" ir - . tr. °a r. - Pfr T 41— aSmall. .e2 Ts r _ as I I. :1• , - nr'' a E ^ f n a - Figure 2. Agricultural Field with Specialty Lettuce Crop (October 26, 2021) IPOM•MIIIL Figure 3. Agricultural Field Planted to Winter Wheat, (October 26, 2021) Ea._ - •1aG .- a• - - - `1 1 r s _ Z -Y' +.x-•1,4 aim -S 2! •••6 - -- :•!_- E,,,, - -. allf.5 A_ wc—. -.— - — ` m L ?T- r ' Inadir Exhibit J Page 4 EXHIBIT C EXHIBIT C - MINING PLAN The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.3 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (a) Specify the estimated dates that mining will commence and end. If the operation is intended to be an intermitted operation as defined in C.R.S 34-32.5-103(11)(b), b), the Applicant should include in this exhibit a statement that conforms to the provisions of Section 31-32,5- 1O3(11)(b), C.R.S; Mining will commence as soon as possible after the approval of this application which is estimated to be in February. The owner of the property is concurrently applying for a DRMS 112 permit and mining under this DRMS 111 permit will end after approval of the 112 permit or once the permittee has reached the grade shown on the mining plan map. The expected end date for the project is December 2023 or earlier if the above conditions are met. (b) the estimated depth to which soil, suitable as a plant growth medium, will be salvaged for use in the reclamation process. This description must be consistent with information provided in Exhibit B. Sufficient soil must be salvaged to meet the vegetation establishment criteria of Rule ..1.10. If plant growth medium is not reapplied on a graded area immediately after salvage, then the Operator/Applicant must specify how the topsoil will be stockpiled and stabilized with a vegetative cover or other means until used in reclamation. Plant growth medium stockpiles must be located separate from other stockpiles, out of the way of mine traffic and out of stream channels or drainageways. The location of plant growth medium stockpiles must be shown on Exhibit E - Map; From the exploratory borings that were drilled at the site in 2021, the estimated suitable sail for plant growth is approximately 12 inches. The top 12 inches of soil will be stockpiled to the southern side of the affected area as shown on the Mining Plan Map in Exhibit E. In the event that the topsoil is not utilized within 180 days vegetative cover will be planted. The Weld County seed mix for areas south of County Road 68 will be used. Areas South of County Road 68 • Mix Western Wheatgrass (Arriba, Barton, Rosana) 2.50 lbs pis/acre Blue Drama (Hachital, Lovington) 1.50 lbs pis/acre • Sideoats Crania (Vaughn, Butte, Niner, El Reno, Haskell) 2.25 lbs pls/acre • Smooth Brame (Lincoln, Manchar) 2.00 lbs pis/acre • Sand dropseed 0.25 lbs pls/acre Perennial Ryegrass (Calibra or Garibaldi tetraploid) 0.75 lbs pis/acre • Slender Wheatgrass (Pryor, Revenue or San Luis) 2.50 lbs pis/acre • Alkaligrass (Fults II, Salt on Sea) 1.25 lbs pis/acre • Switchgrass (Nebraska 28, Blackwell) 1.00 lbs pis/acre Total: 14.00 pound pis/acre (c) specify the thickness of overburden or quantity of waste rock, if any, to be removed to reach the deposit, The location of any overburden stockpiles or waste rock fills must be shown on Exhibit E Map; Section 20 - Gravel Mine — MLRB 111 Permit Amendment Exhibit C Exploratory borings drilled on the site show that overburden is approximately 5 feet deep in the affected area. The permittee is expecting to utilize overburden for the highway project. Any overburden material not suitable for the permitted end use will be stockpiled in the southern end of the affected area adjacent to the topsoil stockpile. (di specify the thickness of the deposit to be mined; Bedrock in the affected area is approximately 48 feet deep and groundwater levels in the area are approximately 18 to 26.0 feet deep depending and depends on season. The pit is expected to be mined to a depth of 10 feet or shallower to avoid exposing groundwater. No groundwater will be exposed during mining under this permit and excavation will remain at least two (2) feet above the groundwater elevation. If groundwater is encountered by the mining operation, the area will be backfilied at least two (2) feet above the groundwater elevation. (e) describe the major components of the mining operation such as: roads and access routes, pit, office, shop/maintenance buildings, plant, processing facilities, and any underground openings such as adits or ventilation facilities. These components must be located on Exhibit E - Map; The access route to the site will be located to the north side of the site and will enter the site off of Weld County Road 44. There will be one pit located to the east of the entrance. The pit will be approximately 29 acres. The location of the access route and pit are shown on Exhibit E-1. (f0 specify the dimensions of any significant disturbances to the land surface such as pit excavations, mine benches, impoundments, stockpiles, waste rock disposal areas, etc; The pit will be approximately 29 acres and the access road area will be approximately 0.73 acres. (g) specify the dimensions of any existing or proposed roads that will be used for the mining operation. Describe any improvements necessary on existing roads and the specifications to be used in the construction of new roads. New or improved roads must be included as part of the permitted acreage. Describe any associated drainage and runoff conveyance structures to include sufficient in forma tion to evaluate structure sizing; An existing 30 feet by 740 feet farm access road will be utilized for the mining operation. No improvements will be made to the existing road. (h) specify how much water will be used in conjunction with the operation, and the source of this water; There will be no onsite processing. The only water used will be for dust suppression at the site. Water will be sourced from United Water and Sanitation's Milliken Reservoir. (i0 if groundwater will be encountered and/or surface water intercepted or disturbed, describe how mining will affect the quantity and quality of the surface or groun dwa ter and the methods to be used to minimize disturbance to the surface and groundwater systems including proposed dewatering, sediment -containment or chemical treatment systems, storm water run-off controls, and groundwater points of compliance; Section 20 - Gravel Mine — MLRB 111 Permit Amendment Exhibit C No groundwater will be encountered, and stormwater run-off will be directed into the pit. No other surface water features will be intercepted or disturbed. UI specify how you will comply with applicable Colorado water laws and regulations governing injury to existing water rights; No groundwater will be exposed during the operation under this permit and no existing surface water conveyances will be disturbed. (k) if refuse and acid or toxic producing materials are exposed during mining, describe how they shall be handled and disposed of in a manner that will control unsightliness and protect the drainage system from pollution; No refuse or add or toxic producing materials are expected to be exposed during mining. If any of these materials are exposed during mining they will be segregated and loaded in the pit to control for unsightliness and to protect the drainage system from pollution. These materials will be disposed of at the appropriate disposal facility. ( describe what measures will be taken to minimize disturbance to the hydrologic ►logic balance, prevent off -site damage, and provide for a stable configuration of the reclaimed area consistent with the proposed future land use; The permittee will not expose groundwater at the site and will direct stormwater from disturbed areas back into the pit. The site is concurrently applying for a DRMS 112 permit along with this ARMS 11i 1i permit. The pit covered in this permit application will ultimately be incorporated into a larger soil-bentonite lined cell that is covered in the DRMS 112 permit. The ultimate final land use for this area is a below grade soil-bentonite lined reservoir. In the event that the DRMS 112 permit application is postponed or denied, the mining pit will be reclaimed as an infiltration pond. (m) specify whether the deposit will be processed on -site. If the deposit will be processed, then describe the nature of the process, facilities and chemicals utilized. The process area and any structures must be described on Exhibit E - Map; There will be no on -site processing. (n) identify the primary and secondary commodities to be mined/extracted and describe the intended use; and The primary commodities to be mined are overburden, sand, and gravel for use as construction aggregates. There will be no secondary commodities mined. (o) name and describe the intended use of all expected incidental products to be mined/extracted by the proposed operation. Topsoil will be stockpiled in the southern portion of the pit. All other materials that are mined are expected to be utilized by the roadway project. Section 20 — Gravel Mine - MLRB 111 Permit Amendment Exhibit C 03) Specify if explosives will be used in conjunction with the mining or reclamation. In consultation with the Office, the Applicant must demonstrate, pursuant to Subsection 6.5(4), Geotechnicaii Stability Exhibit, that off site areas will not be adversely affected by blasting during mining or reclamation operations. No explosives will be used in conjunction with the mining or reclamation. Section 20 - Gravel Mine — MLRB 111 Permit Amendment Exhibit C Exhibit D Reclamation Plan EXHIBIT D - RECLAMATION PLAN The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.4 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: (1) The purpose of the Reclamation Plan is to describe the timing, procedures, criteria and materials that will be used to reclaim the affected land to the proposed future land use. This plan must be correlated to Exhibit E - Map. The description of the Reclamation Plan must be adequate to satisfy the requirements of Section 3.1 and demonstrate compliance with Rule 3. At a minimum, the Application shall include the following information: (a) specify at what point in the mining plan and to what depth(s) overburden will be replaced in relation to ongoing extraction. Overburden will be utilized offsite as a primary commodity and will not be replaced in the mine pit. The pit will be located within the future mine limit of a soil-bentonite lined mine cell under a DRMS 112 permit which has been submitted to the DRMS and is currently under review. In the case that the DRMS 112 permit is delayed or not approved, the mine pit will be reclaimed to an infiltration pond and no overburden will be utilized. (b) specify the maximum gradient of reclaimed slopes (horizontal:vertical). If the Application proposes slopes steeper than 3:1, the Operator/Applicant must include a justification that supports steeper slopes for the proposed post -mining land use, and demonstrates compliance with the applicable performance standards of Section 3.1. The maximum gradient of the mined and reclaimed slope will be at a 3:1. (c) specify the measures that will be taken to revegetate the site, if applicable, including: The site is currently utilized as flood irrigated farmland. The final end use for this area is planned to be water storage or as an infiltration pond. In disturbed areas above the highwater line and outside of the pit the land will be revegetated with the Weld County upland seed mix utilizing the stockpiled topsoil. In the case that the DRMS 112 permit is delayed or not approved, and the mine pit is reclaimed to an infiltration pond the side slopes above the zone used for infiltration will be replaced with 12 inches of topsoil and reseeded with the Weld County upland seed mix. (i) state the thickness of plant growth medium to be replaced. Sample and analyze available soils sufficiently to establish quantity and quality; The affected area is currently flood irrigated cropland that is tilled yearly and left fallow in the winter. The permittee will replace 12 inches of topsoil and reseed disturbed areas outside of the pit with the Weld County Upland Seed Mix, attached to this Exhibit. In the case that the DRMS 112 permit is delayed or not approved and the mine pit is reclaimed to an infiltration pond the side slopes above the zone used for infiltration will be replaced with 12 inches of topsoil and reseeded with the Weld County upland seed mix. Section 20 - Gravel Mine — MLRB 111 Permit Application Exhibit D -1 (ii,)state at what point in the mining plan the site will be seeded. Explain how the seedbed will be prepared to eliminate compacted conditions (e.g., plowed, chiseled, disced). State the type, application rate, and soil incorporation methods of fertilizer application, if any. NOTE: Soil amendments shall only be applied where soil tests indicate nutrient deficiencies for the plant species to be established; The pit will be located in the future mine limit of what will be Phase -1 of a DRMS 112 permit which is currently under review. In the event that mining under this permit is complete prior to approval of the DRMS 112 permit or the DRMS 112 permit is not approved, reclamation will begin and the side slopes above the sand and gravel used as the infiltration zone and outside of the pond will be reseeded. (iii) state the grass, forb, shrub and tree species to be planted and the applicable quantities. Specify the quantity of each grass and forb species as pounds of pure live seed per acre; Areas South of County Road 68 • Mix Western Wheatgrass (Arriba, Barton, Rosana) 2.50 lbs pls/acre • Blue Grama (Hachital, Lo in ton)1. 0 lbs pis/acre • Sideoats Grama (Vaughn, Butte, diner, El Reno, Haskell) 2.25 lbs pis/acre • Smooth Brome (Lincoln, Manchar) 2.00 lbs pis/acre • Sand dropseed 0.25 lbs pls/acre • Perennial Rye rays (Calibra or Garibaldi tetraploid) 0475 lbs plsla re • Slender Wheatgrass (Pryor, Revenue or San Luis) 2.50 lbs pis/acre • Alkaligrass (Fults II, Salt on Sea) 1.25 lbs pis/acre • Switch rays (Nebraska 28, Blackwell) 1.00 lbs pls/acre Total: 14.00 pound pis/acre (iv) specify the application method for grass and forb seeding. If the seed is to be broadcast, the application rate shall be twice the rate required for seed drilling. If the seedbed has not been adequately roughened prior to seeding, the seed shall be raked or harrowed after broadcast application; The seed mixture will be drilled and mulched. (v) if a mulch is needed, specify the kind to be used, the crimping method, and rate of application; and Straw mulch will be at 2 tons/acres and will be incorporated into the soil with a studded roller or crimper. (vi) explain the establishment methods for each species of shrub and/or tree, and state the number of each to be established per acre. Not Applicable (d) Specify which ponds, streams, roads and buildings, if any, will remain after reclamation. Section 20 - Gravel Mine — MLRB 111 Permit Application Exhibit D - 2 These features must be shown on the Exhibit E - Map. If ponds are pad of the Reclamation Plan, slopes from 5 vertical feet above to 10 vertical feet below the expected average water level cannot be steeper than 3H:1V; remaining slope lengths may not be steeper than H: 1V. Where wildlife habitat is the proposed future land use, shorelines should be irregularly shaped to promote a diverse wildlife habitat The Colorado Division of Wildlife (DOW) must be consulted where wildlife use is the proposed future land use. The main pit will remain after reclamation and will either be water storage or a infiltration pond. The whole reclamation slope will be reclaimed at a 3:1 slope. (e) specify the reclamation treatment of any waste rock dumps, underground mine openings, ditches, sediment control facilities, buildings and other features specified in your mine plan but not previously addressed in the Reclamation Plan narrative. These features must be shown on Exhibit E - Map. This should describe the measures taken to minimize disturbance to the hydrologic balance, prevent off -site damage, and provide fora stable configuration consistent with the proposed future land use. All features have been addressed. Section 20 - Gravel Mine — MLF&B 111 Permit Application Exhibit D - 3 EXHIBIT E EXHIBIT F - OTHER PERMITS AND LICENSES The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.6 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: The Operator has obtained or will apply for the following permits prior to mining: Weld County Grading Permit — Weld County Grading Permit will be updated or obtained along with this 111 application Nix — Gravel Mine — MLRB 112 Permit Application Exhibit M - 1 EXHIBIT G - SOURCE OF LEGAL RIGHT TO ENTER The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.7 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: See the attached notarized letter from CAW Equities L.L.C and Red Tierra Equities, L.L.C. stating that Applicant has the legal right to enter. Mx Gravel Mine MLRB 112 Permit Application Exhibit M -1 CAW Equities, L.L.C. Red Tierra Equities, L.L.C. 8301 E. Prentice Ave., Suite #100, Greenwood Village, CO 80111 Telephone (303) 773-1005 • Telecopier (303) 773-1176 January 18, 2022 Jalisco International, Inc. 6663 Colorado Blvd. Commerce City, CO 80022 RE: Legal Right to Enter To Whom it May Concern: In exchange for good and valuable consideration, CAW Equities, L.L.C., and Red Tierra Equities, L.L.C. (collectively the "Property Owners}") hereby grant to Jalisco International, Inc. the right to enter into the real property situated in Section 20, Township 4 North, Range 66 West In The 6th P.M., County Of Weld, State of Colorado. Refer to Exhibit for legal description and Limit of Distance. You and your officers, employees, contractors, and agents have permission to enter upon the Property to borrow (excavate) material within the designated mining pit area as shown in Figure 1 attached hereto. We hereby confirm that you have authority and right to execute all documents required to apply for and obtain permits and to access the property. The permission granted by this letter shall be effective immediately, and shall remain in effect until superseded by a Sand, Gravel and Aggregate Mining Lease or until written notice from the Property Owners, whichever comes first. CAW Equities, L.L.C Red Tierra Equities, L.L.C. Robert A. Lembke, Manager Robert A. Lembke, Manager STATE OF ootfli O ) ss. COUNTY OF Ar�ynihoe ) The foregoing instrument was acknowledged before me on January le, 2022, by obert A. Lembke, as Manager of CAW Equities, L.L.C. and Red Tierra Equities, Witness my hand and seal. My commission expires: 10 ! 1 1 2024 Notary Public MARY BATES NOTARY PUBLIC STATE OF COLORADO NOTARY JD 202 5076 hitr Cor rnfssibn c s # r 07, 2024 Rr5lIURG::4 2 Q Fr '1S3liTIIs NO1iVDflddV' 1ICI'kiad ITT SIAM CI 3NIW "liaNurtiD Ut NOLLD3S Y r I Riti • ala la --aonasir !a tea MED 41•2 1:1 It cw`vi,.• \\ ous a e i e i am • S ti a 4. U VI 41 l-0I5'EMVO LJl'IS&rI4104V AMMAN y5'tmIs smokrEa ?!ISi5'upie Ia VA+oMNU' EXHIBIT - LEGAL DESCRIPTION OF LEGAL RIGHT TO ENTER LANDS 0 fwilpitypescrintion: LEGAL DESCRIPTION SOUTHEAST QUARTER (SE 114) OF SECTION TWENTY (20}, TOWNSHIP FOUR (4) NORTH, RANGE SIXTY-SIX (66) WEST OF THE 6TH P,M, WELD COUNTY, COLORADO LESS AND EXCEPT LOT A, RECORDED EXEMPTION NO, 1057 -24 -4 -RE 1699 AND LESS AND EXCEPT LOT A, RECORDED EXEMPTION NO 1057 -24 -4 -RE 3000 COUNTY OF WELD, STATE OF COLORADO. PARCEL, CONTAINS 6,8'!3,688 SO FT OR 156,40 AC MORE OR LESS And, LEGAL DESCRIPTION PARCEL 1: THE NORTHWEST QUARTER (NW1/4) OF SECTION TWENTY (20) AND THAT PART OF THE NORTHEAST QUARTER (NE1/4) OF SECTION TWENTY (20) LYING WEST OF THAT CERTAIN IRRIGATION LATERAL AS NOW CONSTRUCTED AND EXISTING ACROSS SAID LAND MOWN AS THE BOB CHESTNUT DITCH, ALL IN TOWNSHIP FOUR (4) NORTH, RANGE SIXTY- SIX (66) WEST OF THE 6TH P.M,, COUNTY OF WELD, STATE OF COLORADO, EXCEPTING THEREFROM A STRIP OF LAND 30 FEET WIDE OFF THE ENTIRE NORTH SIDE OF THE N112 OF THE NW1/4 IN DEED RECORDED MARCH 2, 1898 IN BOOK 130 AT PAGE 66, WELD COUNTY RECORDS, AND A STRIP OF LAND 40 FEET WIDE ALONG THE WEST SIDE OF THE NWT 141N DEED RECORDED MAY 25, 1938 IN BOOK 1026 AT PAGE 433, WELD COUNTY RECORDS, PARCEL 2: THE NEI/4 OF SECTION 20, TOWNSHIP 4 NORTH, RANGE 66 WEST OF THE 6TH P.M.; EXCEPT A TRACT OF LAND CONSISTING OF TWO ACRES, MORE OR LESS, LYING IN THE NORTHWEST CORNER OF THE N1N1J4 OF THE NEW OF SAID SECTION 20, BEING ALL THAT PART OF SAID NW1/4 OF SAID NE114, OF SAID SECTION 20, LYING NORTH AND WEST OF THAT CERTAIN IRRIGATION LATERAL CONSTRUCTED ACROSS SAID LAND KNOWN AS THE "BOB CHESTNUT DITCH", AND USED TO CARRY WATER ACROSS SAID LAND FROM THE CANAL OF THE WESTERN DITCH AND LAND COMPANY TO LANDS FORMERLY OWNED BY ROBERT S. CFfESTNUT, AS CONVEYED TO SAMUEL 0. GRIFFITH BY WARRANTY DEED RECORDED IN BOOK1450 150 AT PAGE 369, COUNTY OF WELD, STATE OF COLORADO And, LEGAL DESCRIPTION A PARCEL OF LAND LOCATED IN THE SOUTHWEST QUARTER OF SECTION 20, TOWNSHIP NORTH, RANGE 66 WEST OF THE 6TH PRINCIPAL MERIDIAN, COUNTY OF WELD, STATE OF COLORADO, SAID PARCEL BEING MORE PARTICULARLY DESCRIBED AS FOLLOWS: COMMENCING AT THE WEST QUARTER CORNER OF SAID SECTION 20, WHENCE THE SOUTHWEST UARTER CORNER OF SAID SECTION 20 LIES S 0014'59" WA DISTANCE OF 2647.47, SAID LINE BEING THE BASIS OF BEARINGS; THENCE ALONG THE NORTH LINE OF THE SOUTHWEST QUARTER OF SAID SECTION 20 N 89 42'071 E, A DISTANCE OF 4fl,0D' TO A POINT ON THE WEST RIGHT OF WAY FOR HIGHWAY 80, SAID POINT ALSO BEING THE POINT OF BEGINNING; THENCE CONTINUING ALONG SAID NORTH LINE OF THE SOUTHWEST QUARTER N 89°42'07" E, A DISTANCE OF 2,632.31', TO THE CANTER QUARTER CORNER OF SAID SECTION 20; THENCE ALONG THE EAST LINE OF THE SOUTHWEST QUARTER OF SAID SECTION 20 S 00°33'36' E, A DISTANCE OF 2,815.5$' TO A POINT ON THE NORTH RIGHT OF WAY LINE FOR COUNTY ROAD 42; THENCE ALONG SAID NORTH RIGHT OF WAY LINE S B9°38'42" Val, A DISTANCE OF 2,631 .25' TO A POINT ON THE WEST RIGHT OF WAY FOR HIGH WAY 60; THENCE ALONG SAID WEST RIGHT OF WAY N 0p°34'59" VII, A DISTANCE OF 2,817A' TO THE POINT OF BEGINNING* SAID PARCEL CONTAINS 158,08 ACRES. EXHIBIT H - MUNICIPALITIES WITHIN A Two -MILE RADIUS The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.8 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: The municipalities within a two-mile radius of the site are: The Town of Milliken 1101 Broad Street, Milliken, CO 80543 970-587-4331 The Town of Gilcrest PO Box 128 Gilcrest, CO 80623 970-737-2426 The Town of Plattteville 400 Grand Avenue Platteville, CO 80651 970-785-2245 Mx Gravel Mine MLRB 112 Permit Application Exhibit M -1 EXHIBIT I PROOF OF FILING WITH THE CLERK TO THE BOARD This information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.9 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: The attached letter and full application package was sent by email to the Clerk to the Board of County Commissioners to be placed for public review in Weld County on July 29, 2022. The proof of electronic transmission is attached to this Exhibit. Section 20 - Gravel Mine — MLRB 111 Permit Amendment Application Exhibit I -Proof oH Piling With the County Clerk EXHIBIT J PROOF OF MAILING OF NOTICES TO BOARD OF COUNTY COMMISSIONERS AND SAIL CONSERVATION DISTRICT This information provided in this Exhibit is intended to satisfy► the requirements outlined in Section 6.3.10 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations: The attached letter was sent by email to the Clerk to the Board of County Commissioners to be placed for public review in Weld County on July 29, 2022. The proof of electronic transmission is attached to this Exhibit. The attached letter to the West Greeley Soil Conservation District was hand delivered on July 29, 2022. Section 20- Gravel Mine — MLRE 111 Permit Amendment Application Exhibit I -Proof of Piling With the County Clerk EXHIBIT K - TERMS OF GOVERNMENT CONTRACT The information provided in this Exhibit is intended to satisfy the requirements outlined in Section 6.3.11 of the Colorado Mined Land Reclamation Board Construction Material Rules and Regulations See the attached Notice to Proceed from the Colorado Department of Transportation dated September 23, 2021. Mx Gravel Mine MLRB 112 Permit Application Exhibit M -1 PO #: 461001713 Routing #: 22-HA4-76-0002 3 COLORADO Department of Transportation Contracts and Market Analysis Branch 2829 W. Howard Place, Suite 300 Denver, C,olorad0 80204 Telephone (303) 757-9354 NOTICE TO PROCEED September 23, 2021 JALISCO INTERNATIONAL INC" 6663 COLORADO BLVD COMMERCE CITY, CO 80022 NHPP 0853-107 Peckham Grade Separated Intersection Project Code: 21907 You are hereby notified that on September 22, 2021, the Department of Transportation received a fully executed Contract and Bond, and acceptable evidence of insurance naming Travelers Indemnity Company as the insurer for Colorado Project No. NHPP 0853-107 on US85 AND WCR44 NORTH OF GILCRE.ST IN PECKHAM, WELD COUNTY. We enclose herewith one duplicate original of the contract between this Department and your company. This letter is to verify "Notice to Proceed" was given by email on September 23, 2021, to the Region Construction Office. Work on this project may proceed. Time will be started as provided for in the contract, or when work is started, as authorized by the Engineer. Regards, /Isola 5a)tan, Tracie Benton Con tract Administrator I I T cc: CCU (Trade Benton) Sarah Wintei-/att. (Federal Aid) Business Office (Region 4) Federal Highway Administration Document Builder Generated Rev. 12/09/2016 EEO (Staff Constr.) Traffic Engineer (Region 4) Finals Engineer (Region 4) Risk Management Page 1of3 GEOTECHNICAL STABILITY EXHIBIT December 30, 2021 Mr. Peter Kubiak Jalisco Internation 6663 Colorado Blvd Commerce City, CO 80022 Re: Stability Analysis for the Section 20 Gravel Mine Dear Mr. Kubiac: This letter has been prepared to address the Mined Land Reclamation Board (MLRB) Construction Materials Rule 6, Section 4, Subsection 19, Exhibit S - Permanent Man -Made Structures (6419, Exhibit 8) for the proposed Section 20 Gravel Mine located northeast of the intersection of State Highway 60 and Weld County Road 42 in Weld County, Colorado. This letter describes the project and slope stability analyses utilized to evaluate the minimum distance between the edge of mining and adjacent structures to avoid damage to the structure. The site is located approximately 3/4 of a mile west of the town of Gilcrest. More specifically, the site occupies nearly all of Section 20, Township 4 North, Range 66 West of the 6th Principal Meridian. The mine is in an area of irrigated agricultural land with common oil and gas wells and related infrastructure and is bound by Weld County Road (WCR) 42 on the south, State Highway 60 on the west, WCR 44 on the north, and WCR 29 on the east. The mine will consist of eight (8) cells. One (1) of the cells will be wet mined at a mine slope of 2 horizontal toil vertical (2h:lv) and backfilled with the silt byproduct of the wash plant operation. The other seven (7) cells will be lined with slurry walls and will be dry mined at slopes of 1.5h:1. Based on the stability analyses, this report indicates that the setbacks and perimeter slopes in the mining plan are sufficient to protect structures within 200 feet of the permitted mining boundary. Actual setbacks may be greater due to permit limitations, zoning requirements, construction issues, agreements with owners, and extent of economically mineable aggregate or other issues. GEOLOGY The Site is located approximately 21 miles east of the eastern flank of the Rocky Mountain Front Range. Younger sedimentary strata dip eastward off the Pre -Cambrian igneous and metamorphic rocks that form the core of the Front Range into the Denver Structural Basin. The Denver Basin is an asymmetrical downwarp of sedimentary strata with a steeply dipping west limb and a gently dipping east limb. Bedrock does not crop out at the site, however regional geologic mapping of the area (Colton, 1978) indicates the near surface bedrock beneath the site is most likely the Laramie Formation. Colton (1978) describes the Laramie as mostly claystone, shale, sandy shale, and lenticular sandstone. The Lower Laramie is described as sandstone, sandy shale, and claystone with several coal beds. The regional mapping indicates the bedrock is overlain by the Broadway Alluvium. Colton (1978) describes the Broadway as sand and gravel deposited by the South Platte River and its tributaries that is terraced typically lying about 40 feet above major streams. Along the South Platte River, the Broadway is typically on the order of 35 feet thick but can range up to 125 feet thick. GEOTL CHNICAL CONDITIONS Based on the site investigations, the natural site stratigraphy generally consists of four main units: 1) Overburden: generally consisting of near surface fine to medium grained sand locally grading to silty or clayey sand; 2) Sand and Gravel: alluvial deposits that underlie the overburden and overlie the bedrock; 3) Mud Lens: silty to clayey sand Mr. Peter Kubiak December 30, 2021 Page 2 commonly interbedded within the sand and gravel unit; and 4) bedrock usually consisting of sandy claystone and sandstone that is commonly weathered in the top 1 foot and is commonly interbedded and interlaminated. Overburden The overburden is typically a fine to medium grained sand that locally grades to silty or clayey sand typically ranging from 0 to 7 feet in thickness. This unit is usually slightly moist to moist, loose to medium dense with the top 6 to 8 inches containing significant organics. Of the overburden samples tested, the range of percent passing the No. 200 sieve ranged from 4.1% to 31.9%. Atterberg Limits testing ranged from granular non -plastic to Liquid Limits of 26 and Plasticity Indices of 9. Sand & Gravel The sand and gravel is present throughout the site locally occurring at the surface, but typically underlying the overburden and overlying the bedrock. This unit typically consists of slightly silty, fine to medium grained sand overlying or grading to a a fine to coarse grained sand and/or gravelly sand. This unit is typically medium dense but locally dense. This unit is commonly fifty (50) feet thick but is locally as thick as eighty-five (85) feet. Mud Lens The mud lens unit is locally interlensed within the sand and gravel unit. This unit typically consists of clayey to silty sand. Thickness varies from one (1) foot to as much as fifteen (15) feet. This unit tends to be thicker on the south part of the site. Bedrock The bedrock encountered in the exploratory borings was generally weathered in the upper foot typically became harder in unweathered zones. The bedrock consisted of sandy claystone. Groundwater Groundwater was encountered in all of the borings at approximately 15 to 25 feet below ground surface. The groundwater levels will vary seasonally and will typically rise during the irrigation season and when recharge is applied. Groundwater will be controlled with the proposed below grade slurry wall and by pumping down the water level on the interior of the slurry wall. After slurry wall construction, groundwater mounding is anticipated on the upgradient (south and southeast) side of the site and a groundwater shadow (deeper water table) is anticipated on the downgradient (north and northwest) side the site. From a geotechnical standpoint, the sand and gravel will form the majority of the mine slopes. These soils are generally strong and stable, particularly when dewatered. With the exception of the silt pond, dry mining is planned in the cells as the slurry wall will control water level in the main cell and mining will be above the water table in the other cell. STRUCTURES WITH 200 FEET OF DISTURBED AREAS The known, permanent, man-made structures within 200 feet of the proposed mine areas that are not owned by the miner are listed below: • PDC Energy- Flowline, Flare Stack, Tanks, Oil/Gas Well • DCP Energy- Gas Line • Weld County Public Works- Weld County Road 44 STABILITY ANALYSES Division of Reclamation and Mining Safety (DRMS) staff drafted a policy regarding stability analyses of neighboring structures. The draft summarizes adequate factors of safety (FOS) for non -critical and critical structures. The structures around the Section 20 mine are, for the most part, considered critical structures. The FOS are for both static and seismic Mr. Peter Kubiak December 30, 2021 Page 3 (from an earthquake) stability analyses. For generalized strength assumptions and critical structures, an FOS of 1.5 is considered sufficient for static conditions and an FOS of 1.3 is considered suitable for seismic conditions. The stability of structures within 200 feet of the proposed mining limits was evaluated at three representative sections under anticipated loading conditions around the perimeter of the site as discussed below. The computer program XSTABL was used for the analysis. The method for selecting the critical failure surface for each analyzed loading condition is the following. The Modified Bishop's Method of Analysis is used to find the critical failure surface by randomly searching with 20 termination points and 20 initiation points (400 failure circles) with 7 -foot line segments over a broad range of the slope surface and at the structure in question. This procedure is repeated over different initiation and termination locations until the most critical factor of safety failure surface is identified. The range is narrowed and 20 initiation points and 20 termination points (400 failure circles) with 7 -foot line segments for the final run of 400 circles to determine the lowest factor of safety. Therefore, prior to submitting the final stability run, at least 800 failure surfaces were analyzed to determine the lowest factor of safety. Both static stability under anticipated mining conditions and seismic stability under peak ground acceleration loads were performed. Seismic loading was obtained from the U.S.G.S. Unified Hazard Tool attached to this report. Review of the Hazard Tool indicated a maximum horizontal acceleration of 0.082g with a return period of 2,475 years for the site. The three cross section locations were selected and analyzed as described below. Section 1: This section is in the northwest corner of the site in an area that will be wet mined prior to being backfilled with silt. This section considers a 50 -foot tall highwall at a point where the mine limit is 40 feet from a gas line. The overburden is modelled at 5 -feet thick and a 2 -foot thick mud lens is modeled within the sand and gravel. This is the most critical section to be wet mined as it marks the point where a tall highwall (deepest bedrock) and closest structure coincide. Section 2: This section is the most typical section at the site. This section considers a 50 -foot tall highwall at a point where the mine limit is 30 feet from the slurry wall. The nearest structure is a gas line located 20 feet beyond the slurry wall (total distance 50 feet from the highwall). The overburden is modelled at 5 -feet thick and a 5 -foot -thick mud lens is modeled within the sand and gravel. The analysis was run with failure circles starting at 40 -feet from the highwall. Because the FOS meets DRMS standards, structures can be as close as 40 -feet from the highwall. The nearest structure is actually 50 -feet from the highwall. D Section 3: This section is on the southeast part of the site and is the section with the greatest highwall. This section considers an 85 -foot tall highwall at a point where the mine limit is 73 -feet from the slurry wall. The nearest structure is a gas line located 20 feet beyond the slurry wall (total distance 93 -feet from the highwall). The overburden is modelled at 5 -feet thick and a 15 -foot -thick mud lens is modeled within the sand and gravel. The analysis was run with failure circles starting at the slurry wall. Because the FOS at the slurry wall meets [ARMS standards and all structures are further from the highwall than the slurry wall, all structures in this area will be stable. MATERIAL PROPER TIES The material index and engineering strengths assumed in this slope stability report are discussed below. Overburden and Mud Lens The strength properties for the in situ silty to clayey sand overburden and mud lens were based on field testing data and on our engineering judgment; the following parameters have been used to model the overburden. Dry Unit Weight (pc) Moist Unit Weight (pci) Saturated Unit Weight (pct) Cohesion C' psf Friction Angle Om 103 114 126 50 29 Mr. Peter Kubiak December 30, 2021 Page 4 Alluvial Sand and Gravel The sand and gravel is generally a fine to medium -trained sand overlying a fine to coarse grained sand that is typically medium dense and locally gravelly. The alluvial sand and gravel unit was modeled as follows: Dry Unit Weight Oct) Moist Unit Weigh (pc0 Saturated Unit Weight (pcf) Cohesion C'psf Friction Angle E V 115 119 129 g 35 Bedrock Bedrock below the alluvium is sandy claystone, sandstone and interlaminated to interbedded claystone and sandstone bedrock. Sandstone is typically stronger than claystone. Claystone is generally a weak bedrock. To be conservative, we modeled the bedrock as claystone. For the claystone bedrock, two potential strength conditions were considered. These strength conditions are referred to as: 1) peak strength, and 2) residual strength. Peak strength is the maximum shear strength the claystone bedrock exhibits. The shear strength is made up of both cohesion (diagenetic bonding) and internal friction. Under short-term conditions for unsheared claystone, peak strength governs behavior. If a sheared surface or sheared zone is present within sandy claystone because of faulting, slippage between beds due to folding, past shrink -swell behavior, stress relief, weathering, or from a landslide, the cohesion along the sheared surface is reduced to zero, and the angle of internal friction is decreased, due to alignment of clay minerals parallel to the shear plane. Under these conditions a claystone exhibits its lowest strength known as residual strength. Residual strength bedrock occurs in discrete zones, parallel with the sheared surface or zone, whereas fully softened strength occurs over a broader area (not used in this modeling). Based on data from site investigations, the residual strength claystone was modeled in a 3/4 -foot thick, weathered layer overlying the peak strength bedrock as follows: Dry Unit Weight (pcf) Moist Unit Weight (pcf) Saturated Unit Weight (pcf) Cohesion C' psf Friction Angle On 116 Peak = 126 Residual = 110 Peak = 135 Residual = 133 Peak =100 Residual = o Peak = 29 Residual = 18 Soil-Bentonite Murry Wall The proposed slurry wall will consist of a mix of the overburden clayey to silty sand, alluvial sand, and imported bentonite. The resulting mix will produce a non -Newtonian fluid with some shear strength characteristics based on a reduced friction angle of the overlying overburden. Based on engineering judgment, we modeled the slurry wall as follows: Dry Unit Weight (pcf) Moist Unit Weight (pcf) Saturated Unit Weight (pcf) Cohesion C'psf Friction Angle On NA 112 115 0 0 STABILITY ANALYSES RESULTS The stability analyses assumed the mining will be per the mine plan. The plan includes wet mining i'n the cell to receive silt and dry mining in the other seven (7) cells as the water level in these cells will be controlled by slurry walls. The mine slopes in the wet mined cell will not exceed h:1v. Mine slopes in the slurry wall lined cells will not exceed 1.5h:1v. Setbacks listed in Table 1 (below) indicate the setback from the structure to the mining limits. The setback distance can be increased as needed to address other restrictions. The factor of safety shown below is the minimum factor of safety of the three conditions listed above. Mr. Peter Kubiak December 30, 2021 Page TABLE 1- SLOPE STABILITY REST TS AND SETBACKS Section Location Structure Critical Setback Mine Structure Limit From (ft) Static Factor Safety Structure at of Seismic Factor Safety at Structure (0.082g horizontal) of DRMS Requirement Static/Quake Draft FOS 1 Unlined be (50', wet cell mined 2h:1 v) to Gas Line 40 1.75 1.32 1.511.3 2 Lined Mined 1.5h:lv) Cells (50°, Lary Gas Line 40 1.60 1.32 1.511.3 3 Lined Mined Cells (85', 1.5h:1 Dry v)) Slurry Wall/ Line Gas 73 1.67 1.37 1.5/1.3 CONCLUSIONS Based on the Factors of Safety listed in the table above, the mine will not be a hazard to neighboring structures provided the structure and slurry wall offsets, as well as the perimeter mine slopes, follow the mine plan. LIMITATIONS Our review is based on regional geologic mapping, present mining plans, and in part borehole data by Civil Resources. Stability analyses were performed using typical strength parameters for the various strata in the critical sections. Should the mining plans change or subsurface conditions vary from those portrayed in this letter, we should be contacted in order to re-evaluate the potential affects on permanent man-made structures. Stability analyses were run at the structure in question and were not run on failure surfaces closer to the highwall. Note also that surcharge loads due to temporary material stockpiles and overburden berms were not considered in the analysis. Please call with any questions or comments. Sincerely, Civil Resources, LLC Gary Linden, P.G. Senior Engineering Geologist Attachments: U.S.G.S. Uniform Hazard Tool Earthquake Acceleration XSTABL Model Outputs: Sections 1, 2, and 3 J: Brannan Gilcr st Geology\Stability AnalysiskStability analysis report - Sec 20.doc U.S. Geological Survey - Earthquake Hazards Program Unified Hazard Tool Please do not use this tool to obtain ground motion parameter values for the design code reference documents covered by the U.S. Seismic Design Maps web tools (e.g., the International Building Code and the ASCE 7 or 41 Standard). The values returned by the two applications are not identical. Input Edition Conterminous U.S. 2014 (v4.0.x) Latitude Decimal degrees Longitude Decimal degrees, negative values for western longit... Site Class 760 m/s (B/C boundary) Spectral Period Peak Ground Acceleration Time Horizon Return period in years Hazard Curve Frequency of Exceedence C c C 1e-1 - 1e -2- 1e -3 - le -4- 1e -5 - Hazard Curves Time Horizon 2475 years —e— Peak Ground Acceleration 0.20 Second Spectral Acceleration -ii- 1.00 Second Spectral Acceleration 1e-2 Ground Motion (g) View Raw Data 1e+0 Ground Motion (g) 0.30 - 0.25 - 0.20 - 0.15- 0.10- 0.05- 0.00 - Uniform Hazard Response Spectrum Spectral Period (s): PGA Ground Motion (g): 0.082aii. 0.0 0.1 0.2 0.3 OA 0.5 0.6 0.7 0.8 0.9 1.0 Spectral Period (s) SILTS1 1 - 30-21 7:27 4800 _ 4760 is< 4680 I 4640 4600 Section 20 Silt Pond Static 10 most critical surfaces, MINIMUM BISHOP FOS = 1.745 I u 40 S(} 120 160 200 240 2.80 320 PROFIL Section 20 11 . 0 80.0 90.0 150.0 154.0 180.0 .0 . 0 SOIL 5 114.0 119.0 112.0 110.0 126.0 WATER 1 2 Silt Pond 6 4746.0 4746.0 4741.0 4711.0 4709.0 4696a0 4741a0 4711.0 . 0 4709.0 . 0 4696.0 .0 4695.3 126.0 129.0 115.0 133.0 135.0 62.40 .0 300.0 CIRCL2 20 170.0 4680.0 Static 50.0 . 0 . 0 . 0 100.0 4721.0 4721.0 20 195.0 7.0 80.0 90.0 150.0 154.0 180.0 300.0 90.0 150.0 154.0 180.0 300.0 29.00 35.00 .00 18,00 29,00 35.0 -5.0 FILE: SILTS1 12-30-21 7:26 ft 4746.0 4741.0 4711.0 4709.0 4696.0 4696.0 4741.0 4711.0 4709.0 4696.0 4695.3 . 000 . 000 . 000 , 000 a000 40.0 -45.0 1 1 2 1 2 4 2 1 2 4 5 a a 0 0 0 0 0 1 1 1 1 1 XSTABL File. SILTS1 12-30-21 7:27 * ******4.4-4.4* **4-4-4*********4.4-4************ XSTABL * Slope Stability Analysis using the * Method of Slices * * Copyright (C) 1992 - 2002 * Interactive Software Designs, Inc. * Moscow, ID 83843, U.S.A. * * All Rights Reserved * * Ver. 5.206 96 - 1952 Problem Description : Section 20 Silt Pond Static SEGMENT OUNDARY COORDINATES 6 SURFACE boundary segments Segment x -left y -left x -right y -right Soil Unit Below Segment 1 1 2 1 2 4 No. 1 2 3 4 5 (ft) (ft) (ft) (ft) .0 4746.0 80.0 4746.0 80.0 4746.0 90.0 4741.0 90.0 4741.0 150.0 4711.0 150.0 4711.0 154.0 4709.0 154.0 4709.0 180.0 4696.0 180.0 4696.0 300.0 4696.0 SUBSURFACE boundary segments Segment x -left y -left -right y -right Soil Unit Relow Segment 7 1 7 4 5 Pressure Constant (psf) 29.00 35.00 115.0 18.00 29.00 No. 1 3 4 5 (ft) (ft) .0 4741.0 .0 4711.0 .0 4709.0 .0 4696.0 .0 4695.3 ISOTROPIC Soil Parameters 5 Soil unit (s) specified (ft) 90.0 150. f-, 154.0 180.0 300.0 Soil Unit Weight Cohesion Friction Water Unit Moist Sat. Intercept Angle Surface No. (pcf) (pcf) (psf) (deg) No. 1 114.0 .000 2 119.0 .000 3 112.0 .0 .00 4 110.0 133.0 .000 5 126.0 .000 126.0 .0 129.0 .0 1 1 .000 50.0 .0 .0 .0 1 135.0 100.0 .0 1 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pot) (ft) 4741.0 4711.0 4709.0 4696.0 4695.3 Pore Parameter Ru 1 Water Surface No. 1 specified by 2 coordinate points PHREATIC SURFACE, 2 Point x -water -water No. (ft) (ft) random specified. spaces 1 2 .00 4721.00 300.00 4721.00 A critical failure surface searching method, using a technic ue for generating CIRCULAR surfaces has oeen 400 trial surfaces will be generated and analyzed 20 Surfaces initiate from each of 20 points equally along the ground surface between x and x 170.0 ft 195.0 ft Each surface terminates between x = 35.0 ft and x = 40.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is = 4680.0 ft surface i inclined 7.0 ft line segments define each trial failure ANGULAR RESTRICTIONS The first segment 9f each failure surface will k_>e within the angular range defined Lower angular limit Upper angular limit 3 • • • a -45.0 degrees -5.0 degrees surfaces Factors of safety have * * * * been calculated by the SIMPLIFIED BISHOP MET OD * * * * The most critical circular failure surface is specified by 24 coordinate points Point No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 x -surf (ft) 177.89 170.94 163.96 156.96 149.96 142.97 136.01 129.08 122.19 115.37 108.62 101.96 95.39 88.93 82.60 76.39 70.33 64.42 58.68 53.12 47.74 42.56 37.58 37.09 **** Simplified BISHOP FOS -surf (ft) 4697.05 4696.25 4695.75 4695.54 4695.63 4696.02 4696.70 4697.68 4698.96 4700.53 4702.38 4704.52 4706.95 4709.65 4712.62 4715.87 4719.37 4723.13 4727.13 4731.38 4735.86 4740.56 4745.48 4746.00 1.746 The following is a summary of the TEN most critical Problem Description : Section 2 F0S Terminal Resisting Circle Center 0 Silt Pond Static Radius Initial coord (ft) 37.09 39.86 39.90 39.80 39.62 39.45 39.43 39.97 39.17 38.72 (BISHO Moment (ft -lb ) 0 1. 1.746 2.670E+07 2. 1.748 2.922E+07 3. 1.750 2.845E+07 4. 1.757 2.719E+07 5. 1.759 2.860E+07 6. 1.762 2.705E+07 7. 1.763 2.942E+07 8. 1.764 2.587E+07 9. 1.764 2.932E+07 10. 1.765 3.022E+07 -coorc y-coord (ft) (ft) 155.59 4859.86 169.66 4885.03 164.98 4871.60 157.41 4850.78 162.22 4862.63 154.05 4840.72 165.03 4869.84 149.47 4826.62 164.21 4868.71 169.50 4886.59 (ft) 164.33 190.24 177.34 157.61 169.33 148.74 176.41 135.93 175.21 191.96 END OF F LF x-coord x (ft) 177.89 191.05 189.74 187.11 192.37 188.42 195.00 187.11 193.68 192.37 SILTQl 12 -30- 1 7:22 4800 4760 _ w 4720 a� )7<- 4650 I 4640 4600 Section 20 SlIt Pond Seismic 10 most critical surfaces, MINIMUM ISIS I - OP F0S = 1.322 40 80 120 160 200 XAXLES (feet) 2$Q 320 PR0FIL Section 20 Silt Pond 11 6 * 0 4746.0 80.0 4746.0 90.0 4741.0 150.0 4711.0 154.0 4709.0 180.0 4696.0 .0 4741.0 . 0 4711.0 . 0 4709.0 . 0 4696.0 .0 4695.3 SOIL 5 114.0 119.0 112.0 110.0 126.0 WATER 1 2 126.0 129.0 115.0 133.0 135.0 62.40 .0 300.0 EQUAKE .082 CIRCL2 20 170.0 4680.0 .000 Seismic 50.0 . 0 . 0 . 0 100.0 4721.0 4721.0 20 195.0 7.0 80.0 90.0 150.0 154.0 180.0 300.0 90.0 150.0 154.0 180.0 300.0 29.00 35.00 ,00 18,00 29,00 35.0 -5.0 FILE: 5ILTQ1 12-30-21 7:22 ft 4746.0 4741.0 4711.0 4709.0 4696.0 4696.0 4741.0 4711.0 4709.0 4696.0 4695.3 . 000 . 000 . 000 . 000 . 000 40.0 -45.0 1 1 2 1 2 4 2 1 2 4 5 a a 0 0 0 0 0 1 1 1 1 1 XSTABL File. SILTQ1 12-30-21 7:22 * ******4.4-4.4* **4-4-4*********4.4.4** ********* XSTABL * Slope Stability Analysis using the * Method of Slices * * Copyright (C) 1992 - 2002 * Interactive Software Designs, Inc. * Moscow, ID 83843, U.S.A. * * All Rights Reserved * * Ver. 5.206 96 - 1952 Problem Description : Section 20 Silt Pond Seismic SEGMENT OUNDARY COORDINATES 6 SURFACE boundary segments Segment x -left y -left x -right y -right Soil Unit Below Segment 1 1 2 1 2 4 No. 1 2 3 4 5 (ft) (ft) (ft) (ft) .0 4746.0 80.0 4746.0 80.0 4746.0 90.0 4741.0 90.0 4741.0 150.0 4711.0 150.0 4711.0 154.0 4709.0 154.0 4709.0 180.0 4696.0 180.0 4696.0 300.0 4696.0 SUBSURFACE boundary segments Segment x -left y -left -right y -right Soil Unit Relow Segment 7 1 7 4 5 Pressure Constant (psf) 29.00 35.00 115.0 18.00 29.00 No. 1 3 4 5 (ft) (ft) .0 4741.0 .0 4711.0 .0 4709.0 .0 4696.0 .0 4695.3 ISOTROPIC Soil Parameters 5 Soil unit (s) specified (ft) 90.0 150. f-, 154.0 180.0 300.0 Soil Unit Weight Cohesion Friction Water Unit Moist Sat. Intercept Angle Surface No. (pcf) (pcf) (psf) (deg) No. 1 114.0 .000 2 119.0 .000 3 112.0 .0 .00 4 110.0 133.0 .000 5 126.0 .000 126.0 .0 129.0 .0 1 1 .000 50.0 .0 .0 .0 1 135.0 100.0 .0 1 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pot) (ft) 4741.0 4711.0 4709.0 4696.0 4695.3 Pore Parameter Ru 1 Water Surface No. 1 specified by 2 coordinate points PHREATIC SURFACE, 2 Point x -water -water No. (ft) (ft) random specified. spaced 1 2 .00 4721.00 300.00 4721.00 A horizontal earthquake loading coefficient of .082 has been assigned A vertical earthquake loading coefficient of .000 has been assigned A critical failure surface searching method, using a technique for generating CI CULAR surfaces has oeen 400 trial surfaces will be generated and analyzed. 20 Surfaces initiate from each of 20 points equally along the ground surface between x and x 170.0 ft 195.0 ft Each surface terminates between x = 35.0 ft and x = 40.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y = 4680.0 ft surface. inclined 7.0 ft line segments define each trial failure ANGULAR RESTRICTIONS The first segment of each failure surface will be 3 within the angular range defined by Lower angular limit Upper angular limit r -45.0 degrees -5.0 degrees Factors of safety have been calculated by the * * * SIMPLIFIED HIS OP METHOD * * * * * The most critical circular failure surface is specified by 24 coordinate points Point x -surf y - surf ur f Na. (ft) (ft) 1 177.89 4697.05 2 170.94 4696.25 3 163.96 4695.75 4 156.96 4695.54 5 149.96 4695.63 6 142.97 4696.02 7 136.01 4696.70 8 129.08 4697.68 9 122.19 4698.96 10 115.37 4700.53 11 108.62 4702.38 12 101.96 4704.52 13 95.39 4706.95 14 88.93 4709.65 15 82.60 4712.62 16 76.39 4715.87 17 70.33 4719.37 18 64.42 4723.13 19 58.68 4727.13 20 53.12 4731.38 21 47.74 4735.86 22 42.56 4740.56 23 37.58 4745.48 24 37.09 4746.00 * *** Simplified BISHOP FOS = 1.322 * 4 The following is a summary of the TEN most critical surfaces Problem Description : Section 20 Silt Pond Seismic Terminal coord (ft) (ft -lb) 37.09 39.86 39.90 39.62 39.8 0 39.45 39.43 39.17 38.72 38.66 F0S Resisting (BISHOP) Moment 1. 1.322 2.556E+07 2. 1.329 2.801E+07 3. 1.331 2.727E+07 4. 1.336 2.743E+07 5. 1.336 2.608E+07 6. 1.338 2.594E+07 7. 1.339 2.822E+07 8. 1.340 2.812E+07 9. 1.341 2.898E+07 10. 1.341 2.814E+07 Circle Center x-coord y-coord (ft) (ft) 155.59 4859.86 169.66 4885.03 164.98 4871.60 162.22 4862.63 157.41 4850.78 154.05 4840.72 165.03 4869.84 164.21 4868.71 169.50 4886.59 164.64 4873.48 Radius Initial x-coord x (ft) (ft) 164.33 190.24 177.34 169.33 157.61 148.74 176.41 175.21 191.96 179.24 * * * END OF FILE 5 177.89 191.05 189.74 192.37 187.11 188.42 195.00 193.68 192.37 189.74 •S 50 S4 12 - 0 - .1 11:13 4800 len% it 4700 4650 460C1 4550 0 Section 20 Slurry Wall 50 ft Static 10 most critical surfaces, MINIMUM BIS 50 100 150 200 X AXES (feet) OP FOS = 1k604 300 400 PROFIL Section 20 31 . 0 200.0 215.0 222.5 267.5 275.0 304.0 307.0 304.0 307.0 267.5 307.1 304.1 307.1 222.5 307.2 304.2 307.2 215.0 307.3 304.3 307.3 200.0 307.4 304.4 307.4 . 0 307.5 304.5 307.5 304.6 SOIL 5 114.0 119.0 112.0 110.0 126.0 WATER 1 4 CIRCL2 20 Slurry all 50 S 4696.0 4696.0 ^ 4706.0 4711.0 4741.0 4746.0 4746.0 4746.0 4746.0 4746.0 4741.0 4741.0 4741.0 4741.0 4711.0 4711.0 4711.0 4711.0 4706.0 4706.0 4706.0 4706.0 4696.0 4696.0 4696.0 4696.0 4695.3 4695.3 4695.3 4695.3 4692.0 126.0 129.0 115.0 133.0 135.0 62.40 .0 201.0 305.0 308.0 20 50.0 . 0 . 0 . 0 100.0 4696.0 4697.0 4699.0 4731.0 ft Static 200.0 215.0 222.5 267.5 275.0 304.0 307.0 350.0 304.1 307.1 304.1 350.0 304.2 307.2 304.2 350.0 304.3 307.3 304.3 350.0 ' 304.4 307.4 304.4 350.0 304.5 307.5 304.5 350.0 304.6 307.6 307.6 29.00 35.00 .00 18,00 29.00 FILE: 515054 12-30-21 11:13 ft 4696,0 4706.0 4711.0 4741.0 4746.0 4746.0 4746.0 4746.0 4741.0 4741.0 4741.0 4741.0 4711.0 4711.0 4711.0 4711.0 4706.0 4706.0 4706.0 4706.0 4696.0 4696.0 46-96,0 4696.0 4695.3 4695.3 4695.3 4695.3 4692,0 4692.0 4692.0 . 000 • 000 a 000 a000 . 000 4 2 1 2 1 1 3 1 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 3 5 a a a 0 0 0 0 0 1 � 1 1 1 1 190.0 4680.0 205.0 7.0 315.0 -5.0 320.0 -45.0 XSTABL File: SW50S4 12-30-21 11:13 * ******4.4-4.4* **4-4-4*********4.4.4** ********* XSTABL * * Slope Stability Analysis * using * the * Method of Slices * * * * Copyright (C) 1992 - 2002 * * Interactive Software Designs, Inc. * * Moscow, ID 83843, U.S.A. * * * * All Rights Reserved * * * * Ver. 5.206 96 - 1952 * * * * * * * * **************************4(****** Problem Description : Section 20 Slurry Wall 50 ft Static SEGMENT BOUNDARY COORDINATES 8 SURFACE boundary segments Segment x -left y -left -right y -right Soil Unit Below Segment 4 2 1 2 1 1 3 1 No. (ft) (ft) (ft) (ft) 1 .0 4696.0 2 200.0 4696.0 3 215.0 4706.0 4 222.5 4711.0 5 267.5 4741.0 6 275.0 4746.0 7 304.0 4746.0 8 307.0 4746.0 200.0 215. f -, 222.5 267.5 275.0 04.0 307.0 350.0 4696.0 4706.0 4711.0 4741.0 4746.0 4746.0 4746.0 4746.0 23 SUBSURFACE boundary segments Segment x -left y -left x -right y -right Soil Unit Below Segment 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 No. 1 2 3 4 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 (ft) 304.0 307.0 267.5 307.1 304.1 307.1 222.5 307.2 304.2 307.2 215.0 307.3 304.3 307.3 200.0 307.4 304.4 307.4 .0 307.5 304.5 307.5 (ft) 4746.0 4746.0 4741.0 4741.0 4741.0 4741.0 4711.0 4711.0 4711.0 4711.0 4706.0 4706.0 4706.0 4706.0 4696.0 4696.0 4696.0 4696.0 4695.3 4695.3 4695.3 4695.3 (ft) (ft) 304.1 4741.0 307.1 4741.0 304.1 4741.0 350.0 4741.0 304.2 4711.0 307.2 4711.0 304.2 4711.0 350.0 4711.0 304.3 4706.0 307.3 4706.0 304.3 4706.0 350.0 4706.0 304.4 4696.0 307.4 4696.0 304.4 4696.0 350.0 4696.0 304.5 4695.3 307.5 4695.3 304.5 4695.3 350.0 4695.3 304.6 4692.0 307.6 4692.0 3 23 304.6 4692.0 307.6 4692.0 5 ISOTROPIC Soil Parameters 5 Soil unit (s) specified Soil Unit Weight Cohesion Friction Pore Pressure Water Unit Moist Sat. Intercept Angle Parameter Constant Surface No. (pcf) (pcf) (psf) (deg) Ru (psf) No. 1 114.0 126.0 50.0 29.00 .000 .0 1 2 119.0 129.0 .0 35.00 .000 .0 1 3 112.0 115.0 .0 .00 .000 .0 1 4 110.0 133.0 .0 18.00 .000 .0 1 5 126.0 135.0 100.0 29.00 .000 .0 1 1 Water surface(s) have been specified Unit weight of water 62.40 (pcf) Water Surface No. 1 specified. by 4 coordinate * * * * * * * * * * * * * * * * * 4- 4- * * * * * 4- * ***4-* PHREATIC SURFACE, Point x -water y -water No. (ft) (ft) 1 2 3 4 .00 4696.00 201.00 4697.00 305.00 4699.00 308.00 4731.00 3 points A critical failure surface searching method, using a random specified. spaced technicue for generating CI CULAR surfaces has been 400 trial surfaces will be generated and analyzed. 20 Surfaces initiate from each of 20 points equally along the ground surface between and x Each surface terminates between x and x Unless further limitations elevation at which a surface extends surface. inclined 190.0 ft 205.0 ft 315.0 ft 320.0 ft were imposed, the minimum y = 4680.0 ft 7.0 ft line segments define each trial failure ANGULAR RESTRICTIONS The first segment of each failure surface will within the angular range defined Lower angular limit Upper angular limit • _ . - oy 45.0 degrees -5.0 degrees Factors of safety have been calculated by the * * * SIMPLIFIED BISHOP MET:OD 4k * * * * The most critical circular failure surface is specified by 21 coordinate points 4 oe surface Static Terrni nal coord (ft) 315.10 316.30 315.57 C-4 Point No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Simplified x -surf (ft) 193.95 200.90 207.88 214.88 221.87 228.84 235.76 242.61 249.36 256.01 262.53 268.90 275.10 281.12 286.92 292.51 297.85 302.94 307.76 312.30 315.10 PIS OP FOS y -surf (ft) 4696.00 4695.16 4694.70 4694.63 4694.93 4695.63 4696.70 4698.15 4699.97 4702.16 4704.71 4707.61 . 710.86 _'14.45 -'8.35 4722.57 4727.09 4731.90 4736.98 4742.31 4746.00 1.604 The following is a summary of the TEN most critical ._::blem Description : Section 20 FOS Resisting (BISHOP) Moment (ft -lb) 1. 1.604 2.242E+07 2. 1.605 2.380E+07 3. 1.607 2.307E+07 Circle Center x-coord y-coord (ft) (ft) 212.76 4822.39 209.02 4833.10 212.67 4821.81 Slurry Wall 50 ft Radius Initial x-coord x (ft) ( ft) 127.78 138.20 127.84 193.95 191.58 190.00 316.16 316.27 316.13 315.82 316.48 315.39 315.34 4. 1.609 2.374E+07 5. 1.612 2.282E+07 6. 1.612 2.323E+07 7. 1.613 2.295E+07 8. 1.614 2.349E+07 9. 1.614 2.246E+07 10. 1.619 2.206E+07 210.40 4828.82 212.83 4825.59 213.92 4819.73 213.78 4820.29 211,40 4828,07 215.14 4816.41 217.79 4809.61 134.38 130.54 126.02 126.26 133. 33 122.54 116.42 4- END OF L LE 4- 190.00 197.11 190.00 191.58 193.16 192.37 192.37 S 5004 12: .30- 1 11 4800 4750 _ len% it 4700iner 4 650 I 460C1 4550 Section 20 Slurry WWII 50 ft SeismIc 10 most critical surfaces, MINIMUM BIS I - OP F0S = 1..322 50 100 150 200 X AXES (feet) I 300 400 PROFIL Section 20 31 . 0 200.0 215.0 222.5 267.5 275.0 304.0 307.0 304.0 307.0 267.5 307.1 304.1 307.1 222.5 307.2 304.2 307.2 215.0 307.3 304.3 307.3 200.0 307.4 304.4 307.4 . 0 307.5 304.5 307.5 304.6 SOIL 5 114.0 119.0 112.0 110.0 126.0 WATER 1 4 [QUAKE .082 Slurry all 50 S 4696.0 4696.0 ^ 4706.0 4711.0 4741.0 4746.0 4746.0 4746.0 4746.0 4746.0 4741.0 4741.0 4741.0 4741.0 4711.0 4711.0 4711.0 4711.0 4706.0 4706.0 4706.0 4706.0 4696.0 4696.0 4696.0 4696.0 4695.3 4695.3 4695.3 4695.3 4692.0 126.0 129.0 115.0 133.0 135.0 62.40 .0 201.0 305.0 308.0 .000 50.0 . 0 . 0 . 0 100.0 4696.0 4697.0 4699.0 4731.0 ft Seismic 200.0 215.0 222.5 267.5 275.0 304.0 307.0 350.0 304.1 307.1 304.1 350.0 304.2 307.2 304.2 350.0 304.3 307.3 304.3 350.0 ' 304.4 307.4 304.4 350.0 304.5 307.5 304.5 350.0 304.6 307.6 307.6 29.00 35.00 .00 18,00 29.00 FILE: SW50Q4 12-30-21 11:05 ft 4696,0 4706.0 4711.0 4741.0 4746.0 4746.0 4746.0 4746.0 4741.0 4741.0 4741.0 4741.0 4711.0 4711.0 4711.0 4711.0 4706.0 4706.0 4706.0 4706.0 4696.0 4696.0 46-96,0 4696.0 4695.3 4695.3 4695.3 4695.3 4692,0 4692.0 4692.0 . 000 . 000 a 0 0 V a 0 0 0 . 000 4 2 1 2 1 1 3 1 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 3 5 a a a 0 0 0 0 0 1 � 1 1 1 1 CIRCL2 20 20 + 190.0 205a0 4680.0 7a0 315.0 -5.0 320.0 -45.0 XSTABL File: ST/150Q4 12-30-21 11 * ***4 **4.4-4.4* **4-4-4*********4.4.4** ********* XSTABL * Slope Stability Analysis using the * Method of Slices * * Copyright (C) 1992 - 2002 * Interactive Software Designs, Inc. * Moscow, ID 83843, U.S.A. * * All Rights Reserved * * Ver. 5.206 96 - 1952 Problem Description : Section 20 Slurry Wall 50 ft Seismic SEGMENT BOUNDARY COORDINATES 8 SURFACE boundary segments Segment x -left y -left -right y -right Soil Unit Below Segment 4 2 1 2 1 1 3 1 No. (ft) (ft) (ft) (ft) 1 .0 4696.0 2 200.0 4696.0 3 215.0 4706.0 4 222.5 4711.0 5 267.5 4741.0 6 275.0 4746.0 7 304.0 4746.0 8 307.0 4746.0 200.0 215. f -, 222.5 267.5 275.0 04.0 307.0 350.0 4696.0 4706.0 4711.0 4741.0 4746.0 4746.0 4746.0 4746.0 * * * * * * * * * * * * 23 SUBSURFACE boundary segments Segment x -left y -left x -right y -right Soil Unit Below Segment 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 No. 1 2 3 4 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 (ft) 304.0 307.0 267.5 307.1 304.1 307.1 222.5 307.2 304.2 307.2 215.0 307.3 304.3 307.3 200.0 307.4 304.4 307.4 .0 307.5 304.5 307.5 (ft) 4746.0 4746.0 4741.0 4741.0 4741.0 4741.0 4711.0 4711.0 4711.0 4711.0 4706.0 4706.0 4706.0 4706.0 4696.0 4696.0 4696.0 4696.0 4695.3 4695.3 4695.3 4695.3 (ft) (ft) 304.1 4741.0 307.1 4741.0 304.1 4741.0 350.0 4741.0 304.2 4711.0 307.2 4711.0 304.2 4711.0 350.0 4711.0 304.3 4706.0 307.3 4706.0 304.3 4706.0 350.0 4706.0 304.4 4696.0 307.4 4696.0 304.4 4696.0 350.0 4696.0 304.5 4695.3 307.5 4695.3 304.5 4695.3 350.0 4695.3 304.6 4692.0 307.6 4692.0 3 23 304.6 4692.0 307.6 4692.0 5 ISOTROPIC Soil Parameters 5 Soil unit (s) specified Soil Unit Weight Cohesion Friction Pore Pressure Water Unit Moist Sat. Intercept Angle Parameter Constant Surface No. (pcf) (pcf) (psf) (deg) Ru (psf) No. 1 114.0 126.0 50.0 29.00 .000 .0 1 2 119.0 129.0 .0 35.00 .000 .0 1 3 112.0 115.0 .0 .00 .000 .0 1 4 110.0 133.0 .0 18.00 .000 .0 1 5 126.0 135.0 100.0 29.00 .000 .0 1 1 Water surface(s) have been specified Unit weight of water 62.40 (pcf) Water Surface No. 1 specified. by 4 coordinate * * * * * * * * * * * * * * * * * 4- 4- * * * * * 4- * ***4-* PHREATIC SURFACE, Point x -water y -water No. (ft) (ft) 1 2 3 4 .00 4696.00 201.00 4697.00 305.00 4699.00 308.00 4731.00 3 points A horizontal earthquake loading _fficient of .082 has been assigned A vertical earthquake loading coefficient of .000 has been assigned A critical failure surface searching method, using a random specified. spaced technic ue for generating CIRCULAR surfaces has been 400 trial surfaces will be generated and analyzed. 20 Surfaces initiate from each of 20 points equally along the ground surface between x and x 190.0 ft 205.0 ft Each surface terminates between x = 315.0 ft and x = 320.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y= 4680.0 ft surface. inclined 7.0 ft line segments define each trial failure ANGULAR RESTRICTIONS The first segment of each failure surface will be within the angular range defined by Lower angular limit Upper angular limit 4 •._ • • 45.0 degrees -5.0 degrees surfaces Seismic Terminal coord Factors of safety have S I MPL I FI E been calculated by the D BI S OP MET OLD The most critical circular failure surface is specified by 22 coordinate points Point No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 x -surf (ft) 191.58 198.54 205.53 212.53 219.53 226.49 233.41 240.26 247.04 253.72 260.28 266.72 273.00 279.12 285.06 290.81 296.34 301.65 306.73 311.55 316.11 316.30 **** Simplified BISHOP FOS y -surf (ft) 4696.00 4695.29 4694.94 4694.94 4695.30 4696.00 4697.07 4698.48 4700.23 4702.33 4704.76 4707.52 4710.60 4714.00 4717.70 4721.70 4725.99 4730.55 4735.37 4740.44 4745.75 4746.00 1.322 **** The following is a summary of the TEN most critical Problem Description : Section 20 Slurry Wall 50 ft FQS Resi sting (BISHOP) Moment Circle Center Radius Initial x-coord y-coord x-coord x (ft) 316,30 315.10 315.57 316.16 316.27 316.48 316.13 315.82 315.39 316.35 (ft -lb) 1. 1.322 2.306E+07 2. 1.324 2.173E+07 3. 1.326 2.237E+07 4. 1.326 2.301E+07 5. 1.328 2.212E+07 6, 1,329 2.277E+07 7. 1.330 2.252E+07 8. 1.331 2.225E+07 9. 1.333 .178E+07 10. 1.335 2.235E+07 (ft) (ft) 209.02 4833.10 212.76 4822.39 212.67 4821.81 210.40 4828.82 212.83 4825.59 211.40 4828.07 213.92 4819.73 213.78 4820.29 215.14 4816.41 213.41 4823.59 k 4- � ( f `-` ) 138.20 12!.78 127.84 134.38 130.54 13.33 126.02 126.26 122.54 128.95 END OF L' LE (ft) 191.58 193.95 190.00 190.00 197.11 193.16 190.00 191.58 192.37 194.74 � -k SW85S12-30 1 11: 4 49OO Section 20 Slurry Wall 85 Ft Static 10 most critical surfaces, MINIMUM BIS 48OO .. ta3 47OO 0 57‹ 4600 4500 44OO I p r _ I - OP FOS = 1..669 I I 10-0 20.0 0 400 50.O 600 700 800 X. AXES (jeep PROFIL Section 20 31 . 0 200.0 252.5 275.0 320.0 327.5 400.5 403.5 400.5 403.5 320.0 403.6 400.6 403.6 275.0 403.7 400.7 403.7 252.5 403.8 400.8 403.8 200.0 403.9 400.9 403.9 . 0 404.0 401.0 404.0 401.1 SOIL. 5 114.0 119.0 112.0 110.0 126.0 WATER 1 5 CIRCL2 Slurry Wall 85 8 4670.0 4670.0 4705.0 4720.0 4750.0 4755.0 4755.0 4755.0 4755.0 4755.0 4750.0 4750.0 4750.0 4750.0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670a0 4670.0 4669.3 4669.3 4669.3 4669.3 4666a0 126.0 129.0 115.0 133.0 135.0 62.40 .0 201.5 400.8 403.6 600.0 50.0 . 0 . 0 . 0 100.0 4670.0 4671.0 4673.0 4742.0 4743.0 Ft Static 200.0 252.5 275.0 320.0 327.5 400.5 403.5 600.0 400.6 403.6 400.6 600.0 400.7 403.7 400.7 600.0 400.8 403.8 400.8 600.0 400.9 403.9 400.9 600.0 401.0 404.0 401.0 600.0 401.1 404.1 404.1 29.00 35.00 .00 18.00 29.00 FILE: SW8SS 12-30-21 11:54 ft 4670.0 4705.0 4720.0 4750.0 4755.0 4755.0 4755.0 4755.0 4750.0 4750.0 4750.0 4750a0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670.0 4670a0 4669.3 4669.3 4669.3 4669.3 4666.0 4666.0 4666.0 . 000 . 0 0 0 a 0 0 V a000 . 000 4 2 1 2 1 1 3 1 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 3 5 a a a a 0 0 0 0 0 1 1 1 1 1 20 20 180.0 205.0 4650.0 7a0 400.0 —5.0 410.0 —45a0 XSTABL File: SW855 12-30-21 11: Static Soil Unit 17 * ******4.4-4.4* **4-4-4*********4.4.4** ********* XSTABL * * Slope Stability Analysis * using * the * Method of Slices * * * * Copyright (C) 1992 - 2002 * * Interactive Software Designs, Inc. * * Moscow, ID 83843, U.S.A. * * * * All Rights Reserved * * * * Ver. 5.206 96 - 1952 * * * * * * * * **************************4(****** Problem Description : Section 20 Slurry Wall 85 Ft SEGMENT BOUNDARY COORDINATES 8 SURFACE boundary segments Segment x -left y -left -right y -right Below Segment 4 2 1 2 1 1 3 1 No. (ft) (ft) (ft) (ft) 1 .0 4670.0 200.0 4670.0 2 200.0 4670.0 252.5 4705.0 3 252.5 4705.0 275.0 4720.0 4 275.0 4720.0 320.0 4750.0 5 320.0 4750.0 327.5 4755.0 6 327.5 4755.0 400.5 4755.0 7 400.5 4755.0 403.5 4755.0 8 403.5 4755.0 600.0 4755.0 23 SUBSURFACE Segment x -left Soil Unit Below Segment 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 No. 1 3 4 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 (ft) 400.5 403.5 320.0 403.6 400.6 403.6 275.0 403.7 400.7 403.7 252.5 403.8 400.8 403.8 200.0 403.9 400.9 403.9 .0 404.0 401.0 404.0 boundary segments y -left (ft) 4755.0 4755.0 4750.0 4750.0 4750.0 4750.0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670.0 4670.0 4669.3 4669.3 4669.3 4669.3 x -right y -right (ft) 400.6 403.6 400.6 600.0 400.7 403.7 400.7 600.0 400.8 403.8 400.8 60 0.0 400.9 403.9 400.9 600. 4 f-, 1.0 404.0 401.0 600.0 401.1 404.1 (ft) 4750.0 4750.0 4750.0 4750.0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670.0 4670.0 4669.3 4669.3 4669.3 4669.3 4666.0 4666.0 3 5 Pressure Constant (psf) 29.00 25.00 115.0 18.00 29.00 23 401.1 4666.0 ISOTROPIC Soil Parameters 5 Soil unit (° } Soil Unit Water Unit Moist Surface No. (pcf) No. 1 114.0 .000 2 119.0 .000 3 112.0 .0 .00 4 110.0 133.0 .000 5 126.0 .000 specified Weight Sat. (pcf) 126.0 . 0 129.0 . 0 .0 135.0 .0 404.1 4666.0 Cohesion Friction Pore Intercept Angle Parameter Ru .0 1 1 00 psf) 50.0 .0 .0 1 100.0 1 (deg) .0 1 1 Water surface(s) have been specified Unit weight of water 62.40 (pcf) Water Surface No. 1 specified by 5 coordinate * * * * * * * * * * * * * * * * * 4- 4- * * * * * 4- * ***4-* Point No. 1 2 3 4 5 PHREATIC SURFACE, x -water (ft) .00 201.50 400.80 403.60 600.00 3 y -water (ft) 4670.00 4671.00 4673.00 4742.00 4743.00 points A critical failure surface searching method, using a random technique for generating CIRCULAR surfaces has been specified. 400 trial surfaces will be generated and analyzed. 20 Surfaces initiate from each of 20 points equally spaced along the ground surface between x and x Each surface terminates between x and x 180.0 ft 205.0 ft Li 00 10 . • 0 ft ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y = 4650.0 ft surface. inclined 7.0 ft line segments define each trial failure ANGULAR RESTRICTIONS The first segment of each failure surface will within the angular range defined oy Lower angular limit :- -45.0 degrees Upper angular limit :- -5.0 degrees Factors of safety have been calculated by the * SIMPLIFIED BISHOP METHOD The most critical circular failure surface 4 se is specified by 37 coordinate points Point No. 1 2 3 4 5 6 7 8 V 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 y -surf (ft) 181.32 188.26 195.23 202.21 209.21 216.21 223.20 230.20 237.17 251.07 244.13�/ 1rr� � 257.97 L'�� r^5 �1 . 0 7 2 5 f . 9 / 264.84 271.67 278.44 285.17 291.83 298.43 304.95 311.40 317.77 324.05 330.24 336.33 342.31 348.19 353.96 359.60 365.13 370.52 375.78 380.91 385.89 390.73 395.42 399.95 400.14 * * Simplified PIS I C P FOS y -surf (ft) 4670.00 4669.12 4668.44 4667.97 4667.69 4667.63 4667.77 4668.11 4668.65 f 4669.4 0 4670.35 4671.51 4672.86 4674.42 4676.17 4678.12 4680.27 4682.61 4685.14 4687.86 4690.76 4693.85 4697.13 4700.58 4704.21 4708.01 4711.98 4716.12 4720.42 4724.88 4729.50 4734.27 4739.18 4744.24 4749.44 4754.77 4755.00 1.669 The following is a summary of the T surfaces EN most critical Problem Description : Section 20 Slurry Wall 85 Ft Static FQS Terminal Resisting (BISHO coord Moment (ft) (ft -lb) 400.14 401.15 400.72 400.68 402.29 402.56 400.41 402.84 402.95 402.90 D 1. 1.669 1.264E+08 2. 1.675 1.275E+08 3. 1.678 1.247E+08 4. 1.680 1.226E+08 5. 1.685 1.286E+08 6. 1.686 1.327E+08 7. 1.689 1.208E+08 8. 1.692 1.271E+08 9. 1.693 1.322E+08 10. 1.693 1.246E+08 Circle Center x-coord y-coord (ft) (ft) 214.97 4907.36 218.54 4900.19 221.67 4892.34 226.62 4879.83 220.78 4896.11 211.67 4921.42 227.03 4880.66 226.84 4883.20 214.81 4915.29 233.03 4865.66 Radius Initial x-coord x (ft) (ft) 239.73 181.32 233.40 180.00 225.74 182.63 21 Li .39 229.76 253.10 214.26 218.01 247.23 202,72 * * END OF FILL 182.63 180.00 182.63 187.89 181.32 183.95 180.00 4 4- SW850 12 30-21 11:49 4900 4800 14700 0 4600 4500 4400 Section 2 0 Slurry WaN 85 Ft Seismic 10 most crfical surfaces, IHINIMUM BIS 0 100 200 600 300 400 500 AXES (jeep I - OP FOS = 1.373 700 800 PROFIL Section 20 31 . 0 200.0 252.5 275.0 320.0 327.5 400.5 403.5 400.5 403.5 320.0 403.6 400.6 403.6 275.0 403.7 400.7 403.7 252.5 403.8 400.8 403.8 200.0 403.9 400.9 403.9 . 0 404.0 401.0 404.0 401.1 SOIL. 5 114.0 119.0 112.0 110.0 126.0 WATER 1 62.40 5 EQUAKE Slurry Wall 85 8 4670.0 4670.0 4705.0 4720.0 4750.0 4755.0 4755.0 4755.0 4755.0 4755.0 4750.0 4750.0 4750.0 4750.0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670a0 4670.0 4669.3 4669.3 4669.3 4669.3 4666a0 126.0 129.0 115.0 133.0 135.0 .0 201.5 400.8 403.6 600.0 50.0 . 0 . 0 . 0 100.0 4670.0 4671.0 4673.0 4742.0 4743.0 Ft Seismic 200.0 252.5 275.0 320.0 327.5 400.5 403.5 600.0 400.6 403.6 400.6 600.0 400.7 403.7 400.7 600.0 400.8 403.8 400.8 600.0 400.9 403.9 400.9 600.0 401.0 404.0 401.0 600.0 401.1 404.1 404.1 29.00 35.00 .00 16.00 29.00 FILE: SW8SQ 12-30-21 11:48 ft 4670.0 4705.0 4720.0 4750.0 4755.0 4755.0 4755.0 4755.0 4750.0 4750.0 4750.0 4750a0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670.0 4670a0 4669.3 4669.3 4669.3 4669.3 4666.0 4666.0 4666.0 . 000 . 0 0 0 a 0 0 V a000 . 000 4 2 1 2 1 1 3 1 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 3 5 a a a a 0 0 0 0 0 1 1 1 1 1 .082 .000 CIRCL2 20 20 180.0 205.0 4650.0 7.0 400.0 -5.0 410.0 -45.0 XSTABL File: SW85Q 12-30-21 11:49 • 4.4- - -X4.4-4-*- -X4.4-4-*- - 4.4-4-*- - 4- 4- 4- - - 4-4 ** XSTABL * * Slope Stability Analysis * using * the * Method of Slices * * * * Copyright (C) 1992 - 2002 * * Interactive Software Designs, Inc. * * Moscow, ID 83843, U.S.A. * * * * All Rights Reserved * * * * Ver. 5.206 96 - 1952 * * * * * * * * **************************4(****** Problem Description : Section 20 Slurry Wall 85 Ft Seismic SEGMENT BOUNDARY COORDINATES 8 SURFACE boundary segments Segment x -left y -left -right y -right Soil Unit Below Segment 4 2 1 2 1 1 3 1 No. (ft) (ft) (ft) (ft) 1 .0 4670.0 200.0 4670.0 2 200.0 4670.0 252.5 4705.0 3 252.5 4705.0 275.0 4720.0 4 275.0 4720.0 320.0 4750.0 5 320.0 4750.0 327.5 4755.0 6 327.5 4755.0 400.5 4755.0 7 400.5 4755.0 403.5 4755.0 8 403.5 4755.0 600.0 4755.0 23 SUBSURFACE Segment x -left Soil Unit Below Segment 1 3 2 2 2 3 1 1 1 3 2 2 2 3 4 4 4 3 5 5 5 No. 1 3 4 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 (ft) 400.5 403.5 320.0 403.6 400.6 403.6 275.0 403.7 400.7 403.7 252.5 403.8 400.8 403.8 200.0 403.9 400.9 403.9 .0 404.0 401.0 404.0 boundary segments y -left (ft) 4755.0 4755.0 4750.0 4750.0 4750.0 4750.0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670.0 4670.0 4669.3 4669.3 4669.3 4669.3 x -right y -right (ft) 400.6 403.6 400.6 600.0 400.7 403.7 400.7 600.0 400.8 403.8 400.8 60 0.0 400.9 403.9 400.9 600. 4 f-, 1.0 404.0 401.0 600.0 401.1 404.1 (ft) 4750.0 4750.0 4750.0 4750.0 4720.0 4720.0 4720.0 4720.0 4705.0 4705.0 4705.0 4705.0 4670.0 4670.0 4670.0 4670.0 4669.3 4669.3 4669.3 4669.3 4666.0 4666.0 3 5 Pressure Constant (psf) 29.00 25.00 115.0 18.00 29.00 23 401.1 4666.0 ISOTROPIC Soil Parameters 5 Soil unit (° } Soil Unit Water Unit Moist Surface No. (pcf) No. 1 114.0 .000 2 119.0 .000 3 112.0 .0 .00 4 110.0 133.0 .000 5 126.0 .000 specified Weight Sat. (pcf) 126.0 . 0 129.0 . 0 .0 135.0 .0 404.1 4666.0 Cohesion Friction Pore Intercept Angle Parameter Ru .0 1 1 00 psf) 50.0 .0 .0 1 100.0 1 (deg) .0 1 1 Water surface(s) have been specified Unit weight of water 62.40 (pcf) Water Surface No. 1 specified by 5 coordinate * * * * * * * * * * * * * * * * * 4- 4- * * * * * 4- * ***4-* Point No. 1 2 3 4 5 PHREATIC SURFACE, x -water (ft) .00 201.50 400.80 403.60 600.00 3 y -water (ft) 4670.00 4671.00 4673.00 4742.00 4743.00 points A horizontal earthquake loading coefficient of .082 has been assigned random specified. spaces A vertical earthquake loading coefficient .000 has been assigned A critical failure surface searching method, using a technique for generating CIRCULAR surfaces has oeen 400 trial surfaces will be generated and analyzed 20 Surfaces initiate from each of 20 points equally along the ground surface between x and x Each surface terminates between x and x 180.0 ft 205.0 ft Li Li k1 1 0.0 ft 0.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is = 4650.0 ft surface i inclined 7.0 ft line segments define each trial failure ANGULAR RESTRICTIONS The first segment 9f each failure surface will k_>e within the angular range defined Lower angular limit Upper angular limit 4 • • • a -45.0 degrees -5.0 degrees Factors of safety have * been calculated by the SIMPLIFIED BISHOP MET OD The most critical circular failure surface is specified by 37 coordinate points Point No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 x -surf (ft) 181.32 188.26 195.23 202.21 209.21 216.21 223.20 230.20 237.17 244.13 251.07 257.97 264.84 271.67 278.44 285.17 291.83 298.43 304.95 311.40 317.77 324.05 330.24 336.33 342.31 348.19 353.96 359.60 365.13 370.52 375.78 380.91 385.89 390.73 395.42 399.95 400.14 5 y -surf (ft) 4670.00 4669.12 4668.44 4667.97 4667.69 4667.63 4667.77 4668.11 4668.65 4669.40 4670.35 4671.51 4672.86 4674.42 4676.17 4678.12 4680.27 4682.61 4685.14 4687.86 4690.76 4693.85 4697.13 4700.58 4704.21 4708.01 4711.98 4716.12 4720.42 4724.88 4729.50 4734.27 4739.18 4744.24 4749.44 4754.77 4755.00 surfaces Seismic Terminal coorc (ft) 400.14 401.15 400.72 400.68 402.29 402.56 402.84 402.95 400.41 402.90 Simplified BISHOP EQS = 1.373 4 - The following is a summary of the TEN most critical Problem Description Section 20 Slurry Wall 85 Ft FOS Circle Center Radius Initial Resisting (BISHOP) x -coo rd y-coord x-coord x Moment (ft) (ft) (ft) (ft) (ft -lb) 1. 1.373 1.226E+08 2. 1.378 1.237E+08 3. 1.381 1.210E+08 4. 1.383 1.190E+08 5. 1.385 1.248E+08 6. 1.385 1.287E+08 7. 1.390 1.233E+08 8. 1.390 1.283E+08 9. 1.391 .172E+08 10. 1.392 1.209E+08 214.97 6907.36 218.54 4900.19 221.67 4892.34 226.62 4879.83 220.78 4896.11 211.67 4921.42 226.84 4883.20 214.81 4915.29 227.03 4880.66 233.03 4865.66 239.73 233.40 225.74 214.39 229.76 253.10 218.01 247.23 214.26 202,72 * * END OF FILE 181.32 180.00 182.63 182.63 180.00 182.63 181.32 183.95 187.89 180.00 Hello