HomeMy WebLinkAbout990506.tiff GEOLOGIC AND MINERAL
EVALUATION FOR A PROPOSED
SUBDIVISION TO BE LOCATED IN
SOUTH HALF OF SECTION 14
TOWNSHIP 4 NORTH, RANGE 66 WEST
WELD COUNTY, COLORADO
Prepared for
Intermill Land Surveying
1301 North Cleveland Avenue
Loveland, Colorado 80537
June 4,1998
Commission No.: 1119-95-01-01
Prepared By
FOUNDATION& SOILS ENGINEERING, INC.
5110 Granite Street, Suite D
Loveland, Colorado 80538
EXHIBIT
I
990506
TABLE OF CONTENTS
Transmittal Letter I
Scope 1
Site Description 1
Site Investigation 2
Geology 2
Potential Geologic Hazards and Recommendations 3
Potential Mineral Resources 4
Conclusion 4
List of References 7
Vicinity and Area Geologic Map Figure 1
Sand, Gravel, & Quarry Aggregate Resources Figure 2
990Srp&
FOUNDATION Engineering,
AND SOILS II Inc.
June 4, 1998
Commission No.: 1116-95-01-01
Intermill Land Surveying
1301 North Cleveland Avenue
Loveland, Colorado 80537
Gentlemen:
The enclosed report presents the results of a geologic and mineral evaluation for a proposed
subdivision to be located in the South Half of Section 14, Township 4 North, Range 66 West, Weld
County, Colorado.
We appreciate the opportunity to be of service to you on this project. If you have any questions,
please feel free to call.
Respectfully,
Lc, `5
Thomas W. Finley,
Engineering Geologist
FOUNDATION& SOILS ENGINEERING, INC.
TWF/jle
•
•
5110 Granite Street, Suite D • Loveland, Colorado 80538 • (970) 663-0138 • Fax (970) 663-1660
515 Main Street, Suite C • Longmont, Colorado 80501 • (303) 702-0661 05-o
SCOPE
The following report presents the results of our geologic and mineral evaluation for a proposed
subdivision situate in the South Half of Section 14, Township 4 North, Range 66 West of the 6th
Prime Meridian, Weld County, Colorado.
It is our understanding that the 104.45+ acre site is to be divided into three(3) residential lots, two
(2) commercial lots and one (1) agricultural lot. The purpose of this investigation is to identify
potential geologic hazards and potential mineral resources which may conflict with the development
intended. The conclusions and recommendations presented in this report are based upon the acquired
field data, review of the available literature, and previous experience with similar geologic conditions
in this area.
SITE DESCRIPTION
The site is located northeast of Gilcrest at the northeast corner of County Road Nos. 44 and 33.
U.S. Highway 85 is located along the southeast boundary The parcel consists corn and sugar beet
fields which have gradual slopes to the south and east. An irrigation water well is located near the
center of the west side along Cqunty Road No. 33 An existing gas well and tank battery are located
near Highway 85 at the center and south ends. Pipelines and other gas facilities are located nearby.
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990576:
SITE INVESTIGATION
The site was visually inspected on June 4, 1998. The locations of geologic features are approximate
and should be considered only to the degree implied by the methods used to make those
measurements. A preliminary radiation survey was also conducted at this time.
GEOLOGY
The proposed site lies near the eastern edge of the Colorado Piedmont Section of the Great Plains
Physiographic Province. The Colorado Piedmont is an elongated trough in the Great Plains,adjacent
to the Front Range of the Southern Rockies. The Colorado Piedmont was formed when uplift of the
area in Miocene-Eocene times (20 - 50 million years ago) produced an increase of stream erosion
resulting in scouring next to the foothills and outlying areas. The Piedmont is bordered by the
southern Rockies to the west, Great Plains escarpment to the northeast, and Palmer Divide to the
south. The boundary of the eastern edge Colorado Piedmont is not well defined.
Structurally, the site lies in the Denver Basin, which is a thick accumulation of Paleozoic and
Mesozoic Era sediments involved with down warping in the basin area and uplift of the adjacent
highlands. It is our understanding that faulting has not taken place in the recent historic past in this
area. This area is classified as being in Seismic Zone 1 (Uniform Building Code- Chapter 23).
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The site is overlain with surficial alluvial sandy and gravelly soils. These soils consist primarily of
sand with gravel and silt. The Soil Conservation Service maps indicate the property is overlain with
sandy foams with low potentials for erosion.
The Upper Cretaceous Larimie Formation underlies the surficial soils. The Laramie Formation
consists of shale, sandstone and minor coal beds. The thickness of Laramie Formation is in the order
of several hundred feet in this area. Outcrops of the bedrock were not observed.
POTENTIAL GEOLOGIC HAZARDS AND
RECOMMENDATIONS
The alluvial soils are typically stable for supporting structures and roadways. Large fluctuations of
groundwater levels are often associated with alluvial soils such as these. A geotechnical investigation
should be conducted at each site to identify if these conditions exist. Our preliminary radiation survey
detected no radiation levels higher than background levels. Sandstones of the Laramie Formation
have been considered a potential uranium deposit. However,the anticipated depths of the overburden
alluvial soils should minimize the chances of radon infiltration from the underlying Laramie
Formation. In any case, we recommend that the homes be tested for radon after a normal living
routine has been established. Remedial measures could take place after those results if necessary.
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POTENTIAL MINERAL RESOURCES
The Colorado Geological Survey describes this site as being in stream terrace deposits comprised of
sands. The quality and overburden thicknesses and depths to extractable ratios were not readily
available or determined. The were no old or existing gravel mining operations observed in these
deposits within two (2)miles of the site. Therefore, we believe that the alluvial soils on this property
should not be considered extractable mineral aggregate resources at this time. Additional site work
consisting of test pits and laboratory analyses will be necessary to evaluate these deposits more
closely. These may become considered economical sometime in the far future.
CONCLUSION
The soils are considered to be generally stabile for supporting foundations and roadways.
Groundwater conditions should be determined from test boring data prior to construction. A
geotechnical investigation should be conducted for each building site to determine site specific
conditions and generate recommendations for construction. Radon tests are recommended after a
living routine has been established. The sands and gravels anticipated on the property are not, in our
opinion an economical mineral aggregate resource at this time. Additional site evaluation would be
necessary to determine the quality and extent of these deposits for a final determination if these
deposits are of economical importance.
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In conclusion, we feel that the development intended is compatible with the geologic conditions at
the site provided the recommendations in this report are met.
The data presented herein were collected to help determine the feasibility of this project. Professional
judgments on design alternatives and criteria are presented in this report. These are based on
evaluation of technical information gathered, partly on our understanding of the characteristics of the
development proposed,and partly on our experience with geologic conditions in the area. We do not
guarantee the performance of the project in any respect, only that our geologic study and judgments
rendered meet the standard of care of our profession.
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LIST OF REFERENCES
Schowochow, S.D., SchrobaR.R.,and Wicklein,P.C.,Atlas of Sand,Gravel,and Quarry Aggregate
Resources-Colorado Front Range Counties, Colorado Geological Survey, Special Publication 5-B,
1974.
Rogers,W.P.Ladwig,L.R.,Hornbaker,A.L., Schwochow, S.D.,Hart, S.S., Shelton,D.C., Scroggs,
D.L., and Soule, J.M., Guidelines and Criteria for Identification and Land-Use Controls of Geologic
Hazard and Mineral Resource Areas, Colorado Geological Survey, Special Publication 6, 1974.
Tweto, Ogden, Geologic Map of Colorado, US Geological Survey, 1979
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Project No. 1116-95-01-01
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SAND, GRAVEL 4 QUARRY
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Based on: Colorado Geological Survey
Special Publication 5-B
FOUNDATION 4 SOILS ENGINEERING FIGURE NO. 2
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Project No. 1116-95-01-tat
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VICINITY AND AREA
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FOUNDATION 4 SOILS ENGINEERING FIGURE NO. 1
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