HomeMy WebLinkAbout20101988.tiff Epviropnept,,. Inc.
LARRY E. O'BRIAN 7985 VANCE DRIVE,SUITE 205A
FOUNDER C: 25 ARVADA, COLORADO 80003
STEVAN L. O'BRIAN 303-423-7297
PRESIDENT FAX 303-423-7599
August 26, 2010
Weld County Clerk to the Board
915 10th Street CERTIFIED RETURN
Greeley, Colorado 80631 RECEIPT REQUESTED
ITEM # 70040750000256924702
Re: Adequacy Response #2
Firestone Gravel Resource
Permit # M-1996-052
Dear Sir/Madam:
We are delivering to you herewith a copy of the second
adequacy review comments and permit changes for the amendment of
the Firestone Gravel Resource, a Regular ( 112 ) Construction
Materials permit. This copy of the adequacy review packet should
be placed with our original book so it is available for public
review.
The return receipt card that was attached to theis packet
will serve as proof atht we delivered this packet to yor office.
Thank you for your help.
Yours truly,
Stevan L. O'Brian
President
enclosure
Pubk C I_ t) 2010-1988
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LARRY E.O'BRIAN 7985 VANCE DRIVE,SUITE 205A
FOUNDER ARVADA,COLORADO 80003
STEVAN L.O'BRIAN 303-423-7297
PRESIDENT FAX 303-423-7599
August 25, 2010
Mr. Eric Scott
Division of Reclamation, Mining & Safety
1313 Sherman St. , #215
Denver, CO 80215
Dear Eric;
RE: L.G. Everist, Inc.
Firestone Gravel Resource, Permit # M-1996-052
Adequacy Response #2
On behalf of our client L.G. Everist, Inc . , I will respond to
your April 30, 2010 adequacy review letter in the order and
number format presented in that document.
Exhibit C - Pre-Mining and Mining Plan Maps (Rule 6.4.3)
The Division understands that the locations and configuration of some future structures (such as concrete batch
plant and conveyor belts) is not currently known, and that it will be several years before they are constructed on
site. A Technical Revision will be required at a later date to add any of these structures/features and provide
details not specifically included at this time. Also be aware that placing structures of any kind, including
excavations and reservoirs, in the designated flood plain will be subject to approvals from Weld County and
FEMA (conditional letter of map revision, etc.) There will also be bonding implications for the removal of any
structures placed on-site.
We would like to avoid having to do a Technical Revision as
mining resumes to add the Concrete and Asphalt Batch Plants .
However, at this time the exact location of the concrete and
asphalt plants within the Plant Site are unknown. To resolve
this I have provided sketches of the typical layout of each
plant within a plant envelope (Adequacy Exhibits AD-1 , AD-2 , &
AD-3 ) . The location of each plant envelope would be within
the Plant Site area shown to the Mining Plan Map but the exact
location of each plant will be governed by the need as
operations resume and the flexibility when laying out the
plant site as needed at that time.
According to FEMA, equipment associated with mining operations
are not considered structures and therefore do not need to be
elevated. The plants proposed are temporary facilities , and
if flooding occurred would not be impacted by the water as
only the supports would be underwater and water would flow
ENVIRONMENT, INC. PAGE 2
ADEQUACY RESPONSE #2
L.G. EVERIST, INC. • FIRESTONE GRAVEL RESOURCE
AUGUST 25, 2010
around or through them. Attached is a copy of FEMA's
definition confirming these plants do not need to be elevated.
As noted in the first adequacy response L.G. Everist typically
uses 100 yds of concrete for foundations of the various
plants, buildings, scale, parking pads and support structures
associated with the plants . The conveyor is a temporary
structure that moves as mining progresses since it is used in
place of haul trucks . It has no permanent foundation as it
has to be moved regularly to accommodate mining. If mining
ended prematurely, the equipment would be removed, leaving
only the concrete foundations of the plants that would need to
be demolished. Disposal could take place on the site by
burying it in the backfill area.
Portions of the site lie within the 100 yr flood plain of the St Vrain. Any excavations created that intersect the
flood plain will need to have armored inlet-outlet structures appropriately sized and placed to allow floodwaters
to enter and exit without damage. Please address this issue in the mining plan and show required features as
appropriate on the Mining and Reclamation Plan maps.
FEMA' s currently approved and mapped floodplain shows that the
floodplain does intersect the site, however, at this time,
there are questions as to how the floodplain and L.G.
Everist ' s operations would affect or not affect each other.
The flood plain location has been placed on the revised Pre-
Mining Map, Map Exhibit - C attached for your review. A
floodplain study may or may not be required by the county.
Until that information is available we can not design the
requested inlet/outlet structures . Nor are we even sure they
are needed. We will submit the floodplain conclusions and
information once we have it. We will commit to submitting the
design of these structures, if needed, prior to moving into
the area east of the old railroad bed. At this time we have
an approved Flood Plain permit from Weld County that allows
operation west of the old railroad grade.
Exhibit D- Mining Plan (Rule 6.4.4)
Also be aware that placing structures of any kind, including excavations and reservoirs, in the designated flood
plain will be subject to approvals from Weld County and FEMA (conditional letter of map revision, etc.) It
seems likely, based on the configuration of the existing flood plain as shown on the provided FEMA map, that
the removal of the existing elevated rail-bed may have impacts on the extent of the flood plain that will also
need to be addressed as appropriate with Weld County and FEMA.
Thank you for the information. We have an approved Flood
Plain Permit from Weld County for the original permit area
west of the railroad (Permit #FHDP-263 ) . We anticipate being
in here for 3 to 5 years and do not expect to breach this
barrier. By that time we believe the county will have
resolved the floodplain location. L.G. Everist, Inc . will
address all required flood plain issues with Weld County and
FEMA as necessary.
ENVIRONMENT, INC. PAGE 3
ADEQUACY RESPONSE #2
L.G. EVERIST, INC. - FIRESTONE GRAVEL RESOURCE
AUGUST 25, 2010
Exhibit E- Reclamation Plan (Rule 6.4.5)
The Division understands that this property will now be reclaimed primarily as compacted clay-lined dry
excavations with rangeland vegetation. This differs significantly from the original reclamation plan submitted
which was primarily unlined open water lakes. It would be appropriate under these circumstances to provide this
"dry lined excavation" scenario as a primary reclamation plan, with an alternative reclamation plan to fill the
lined excavations as lakes if it becomes feasible in the future for the operator to do so. This would allow either
option (vegetated excavations or reservoirs) to be implemented without the need for another permit amendment
to modify post mining-land use. Appropriate reclamation plans and maps and will need to be provided for both
proposed scenarios.
This is a good suggestion. Attached is an addendum page to go at
the end of the existing reclamation plan and color maps for each
scenario as you suggested. The cost of purchasing water to fill
a reservoir is unknown at this time, so we believe bonding should
be based on the scenario involving revegetating the mined area as
proposed in Adequacy Response #1 .
Exhibit F- Reclamation Plan Map (Rule 6.4.6)
Reclamation Map(s) will need to be updated to show flood water inlet/outlet structures as required for
excavations/reservoirs within the 100 yr flood plain.
If a floodplain study is needed, and if it is determined that
inlet/outlet structures are needed, L.G. Everist will file a
Technical Revision to add the inlet/outlet structures to the
Reclamation Plan Map.
Exhibit G - Water Information (Rule 6.4.7)
Please provide the following information:
The adequacy comments state that "LG Everist, Inc. proposes implementing corrective actions when groundwater
levels at the exterior monitoring holes have dropped 5 feet or more from the monthly average drop established
during monitoring." Specifically, which "exterior monitoring holes" does this statement refer to? LG Everist
should evaluate/consider if their current groundwater monitoring points will be sufficient to defend them against
claims of off-site impacts to the nearby wells.
Along the east side MW-3 , MW-4 and MW-5 . On the south MW-1
and on the north MW-7 and MW-13 . L.G. Everist, Inc . is in the
process of evaluating the current monitoring points and
planning locations for additional groundwater monitoring
Piezometers around the site.
The change from unlined to compacted clay lined reservoirs also introduces the potential for groundwater
mounding/shadowing. There are currently no plans for a French drain or any other mitigation against
groundwater mounding/shadowing. Again, LG Everist should consider if their current groundwater monitoring
points will be sufficient to defend them against claims of off-site impacts from this new configuration.
The existing monitoring Piezometers and any new monitoring
points will be used to monitor changes to the ground water
table outside the liner. If ground water mounding occurs, it
would happen along the south side of the mine and would only
ENVIRONMENT, INC. PAGE 4
ADEQUACY RESPONSE #2
L.G. EVERIST, INC. - FIRESTONE GRAVEL RESOURCE
AUGUST 25, 201 0
affect property owned by L.G. Everist, Inc . , since surrounding
properties are higher then the top of the liner . If needed, a
surface groundwater collection ditch can be constructed along
the south side of the site to intercept and regulate the
mounding. The bottom of the ditch will be placed at the
maximum historic groundwater elevation we have observed during
monitoring. Water collecting in this ditch will be directed
into the seep ditch outlet on the east side of the mined area
and allowed to return to the river.
Are there any downstream users of the "Seep Ditch" that have filed for water rights that would be impacted by
its removal on-site? Will removal of the "Seep Ditch" on-site impact irrigation return flows?
There are no records of water rights listed in SEO's records
for the "Seep Ditch" . The seep ditch flows from the L.G.
Everist mine site to an adjacent mine site, and then
disappears. The adjacent mine site does not need extra water
crossing their land, and as said above, the property owners
never filed for water rights on the seep ditch. Since
irrigation on this site will end as mining progresses there
will be no irrigation runoff from the land so the ditch is not
needed. If needed, a replacement ditch can be constructed
along the southern perimeter of the liner in Stage 5 over to
where the ditch has historically crossed under WCR 17 .
Exhibit L - Reclamation Costs (Rule 6.4.12)
The revised reclamation estimate provided is much better than most, and the Division will accept the proposed
method of dewatering cost calculation/estimate. The changes proposed to the reclamation plan (clay liners,
primary/secondary scenarios) may require some modifications to the estimate breakdown to facilitate a phased
approach. The statements in the submitted adequacy letter that "resumption of mining is delayed for the next
couple of years" and "We do not believe it is necessary to post a large just before we come out of temporary
cessation" also will require some clarification. By Rule, bond to cover reclamation of the existing disturbance
(including the existing scale house, stockpile removal, draining and resloping/lining of existing excavation,
exposed surface water, revegetation, weed control, etc.) should be in place now -regardless of the site's temporary
cessation status. This site has an existing posted bond of$49,450 and is currently under-bonded. In addition, the
bond revision due to the expansion of activities in this amendment will be due within 365 days from the date the
Division approves the amendment unless the bond is phased appropriately and stated as an enforceable condition
in the amendment application.
To address these issues, the Division requires at a minimum (and as a suggested first phase of a phased
approach), adjusting the existing bond as appropriate to reclaim the existing disturbances. The second phase of
this approach could be to post adequate bond to cover the first phase of renewed mining activities as outlined in
this amendment immediately prior to bringing the site out of temporary cessation.
Let' s calculate the bond for the first two phases as the
Division suggests, so that L.G. Everist can take the site out
of temporary cessation sooner, rather than later . L.G.
Everist will post the calculated increase in bond prior to
bringing the site out of Temporary Cessation. Later, as
mining progresses into new areas, we can submit a Technical
Revision to adjust the bond accordingly. Attached is a bond
•
ENVIRONMENT, INC. PAGE 5
ADEQUACY RESPONSE #2
L.G. EVERIST, INC. • FIRESTONE GRAVEL RESOURCE
AUGUST 25, 201 0
estimate based on having most of the existing permit area west
of the old Railroad bed disturbed and partially reclaimed. I
have attached a Bond map showing the area of disturbance.
The Division understands that the excavated "lake" areas will now have a compacted clay liner to satisfy the
SEO requirements and may not, in fact, be filled prior to release. In order to qualify for the 20% bonding option
for a compacted clay liner, the operator will need to provide design specifications for the liner that satisfy, at a
minimum, the requirements of the clay backfill pit liners portion of the "Guide to Specification Preparation for
Slurry Wall and Clay Liners as a Component of a Colorado Mined Land Reclamation Permit" document dated
September 2000 and available on the DRMS web site.
Attached is a copy of, the PROJECT MANUAL FIRESTONE GRAVEL RESOURCE
SLOPE LINER containing the design specifications for the
proposed liner. This document was prepared by Deere & Ault
Consultants, Inc. to meet the requirements outlined in the
"Guide to Specification Preparation for Slurry Wall and Clay
Liners as a Component of a Colorado Mined Land Reclamation
Permit" . With the approval of these design specifications,
the 20% bonding option will apply.
Please also provide the linear feet of compacted clay liner that will be required for each excavated ("lake") area.
This will allow a much easier calculation of the bond required for each phase of the operation as well as
facilitate bond releases when any individual lined phase passes SEO testing.
LAKE LINER AVERAGE FILL PER
AREA LENGTH (FT) LINEAR FOOT. (YDS)
PHASE 2 5, 090 60 . 0
PHASE 3 12 , 245 53 . 5
PHASE 5 16, 865 40 . 5
Exhibit S • Permanent Man-made Structures (Rule 6.4.19)
The Division has received proof that the operator has pursued agreements with all structure owners within 200'.
If additional agreements are executed by structure owners in the future, please forward copies to the Division for
• inclusion in the site record.
Thank you, we will keep the file up to date if/when additional
agreements become available.
Although not specifically required, it would likely be in the best interest of LG Everist to renew old agreements
with existing structure owners that have been carried forward from the previous permittees (EnCana, Last Chance
Ditch).
Discussions are underway with all the oil companies and the
ditch company to get updated agreements for the site. Once
available, they will be submitted to the Division for the
record.
LIST OF ATTACHMENTS TO THIS RESPONSE:
Revised Pre-Mining Map, Map Exhibit -C Typical Processing Plant Layout (AD-3)
Typical Concrete Plant Layout (AD-1) FEMA"Structure" definition
Typical Asphalt Plant Layout (AD-2)
•
ENVIRONMENT, INC. PAGE 6
ADEQUACY RESPONSE #2
L.G. EVERIST, INC. - FIRESTONE GRAVEL RESOURCE
AUGUST 25, 201 0
Reclamation Plan Addendum
Reclamation Plan Addendum Maps (AD-4 & AD-5)
Exhibit L Reclamation costs (revised) & bond map
Liner design specifications
I hope these responses have addressed the adequacy questions
you had. I will place a copy of this packet with the Weld County
Clerks office as required. If you have any questions please call
me.
Sincerely,
Environment, Inc
Stevan L. O'Brian
President
cc L.G. Everist, Inc.
Weld County Clerk
file
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Structure
NFIP Policy index
• Definition/Description
• NFIP Requirement
• Other Applicable NFIP Regulations
• Guidance
• Related Keywords
• Supplemental Information for Structure
Definition/Description
For floodplain management purposes, a structure is a walled and roofed building, including a gas or liquid
storage tank, that is principally above ground, as well as a manufactured home. The terms "structure" and
"building" are interchangeable in the NFIP. Residential and non-residential structures are treated differently.
A residential building built in a floodplain must be elevated above the Base Flood Elevation (BFE).
Non-residential buildings may be elevated or floodproofed.
NFIP Requirement
• 60.3 - Flood plain management criteria for flood-prone areas
o (a) (4) - Subdivision Review
o (b) (3) - BFE Data Requirement
Other Applicable NFIP Regulations
• 59.1 - Definition
• 60.3 - Flood plain management criteria for flood-prone areas
o (a) (1) - Development Permit
o (a) (3) - Reasonably Safe From Flooding
o (c) (2) - A Zone Residential Buildings
o (c) (3) - A Zone Nonresidential Buildings
o (c) (7) - Zone AO Residential Buildings
o (c) (8) - Zone AO Residential Buildings
o (e) (4) - V Zone Structures
Guidance
• IS-9 Managing Floodplain Development Through The National Flood Insurance Program(NFIP) (page
5-28) (PDF 8MB, TXT 1MB) (entire document)
Related Keywords
• Accessory Structures
• Addition
• Basement
• Development
• Elevation
• Floodproofing
• Lowest Floor
• Manufactured (Mobile) Home
• Permit for Floodplain Development
• Substantial Improvement
Supplemental Information for Structure
"Structure" for insurance coverage purposes, means a walled and roofed building, other than a gas or liquid
storage tank, that is principally above ground and affixed to a permanent site, as well as a manufactured
home on a permanent foundation. For the latter purpose, the term includes a building while in the course of
construction, alteration, or repair, but does not include building materials or supplies intended for use in such
construction, alteration or repair, unless such materials or supplies are within an enclosed building on the
premises.
L.G. Everist, Inc.
Firestone Gravel Resource
Permit # M-1996-052
Reclamation Plan Addendum
August 25 , 2010
This addendum is a minor change to the proposed final reclamation
plan to allow for more flexible development of the site. The
revised plan is to have two options for final reclamation depend-
ing on the conditions at the mine as the liner is completed in
each excavated area. The methods and plans for grading,
resoiling and revegetation are unchanged from what is described
in Exhibit E. As originally proposed the site was to be a series
of 3 unlined gravel mine lakes . During the review process we
decided that lining the excavated area was a more practical way
to deal with evaporation off the lake surfaces and having to
supply permanent replacement water. Since we planned to install
a dirt liner around the perimeter we felt it was practical and
cost effective to just make this a compacted liner that would
seal out ground water leaving the site dry or suitable for use as
a developed water storage reservoir. The liner design submitted
was prepared following the "Guide to Specification Preparation
for Slurry Wall and Clay Liners as a Component of a Colorado
Mined Land Reclamation Permit" and the constructed liner will be
certified by the Office of the State Engineer's as part of the
reclamation process . The original Map Exhibit F shows how the
site will be graded and shaped under both options .
OPTION 1
This option is based on there being no water available to fill
the lined area at the time of reclamation thus leaving a dry hole
in the ground. Under this option the floor and side slopes of
the excavated area will be resoiled with eight ( 8 ) inches ± of
topsoil and revegetated using the proposed seed mix. The
revegetated area will remain as is until it is practical to
convert the lined areas to reservoirs . Exhibit AD-4 is a color
version showing the mined areas as being revegetated. This color
map supplements Figure E-1 in the application packet.
OPTION 2
This option is to fill the lined areas creating a developed water
storage reservoir. Since the liner will be installed according
to the design criteria provided in the permit packet. The site
would then be available for filling with water upon final certif-
ication. The various areas of reclamation will be the same as
shown in the Reclamation Timetable of the application. The above
water area would be resoiled with 8 inches of topsoil and seeded
with the proposed seed mix. The first filling would complete
reclamation on the reservoir areas . Exhibit AD-4 is a revised
Figure E-1 to show reservoirs instead of lakes other wise no
changes have been made to that figure.
L . G . LVLFRISI , INC EXHIBIT AD -A-
F I RE ST ONE GRAVEL RESOURCE
OPTION # 1 - REVEGETATED AREAS •�•�•�-,._.7 ;.—.—.—.�.-.-.-.---$
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SIDC'HILL DITCH
- - - AFFECTED LANDS/PERMIT LINE X00. 2010 - I' fl &
DITCH
REVEGETATED
ROADS & GRAVELED AREAS
NON MINING RECLAIMED AREA
NOTE: NON COLORED AREA ARE SETBACKS. DITCH AREAS. PIPELINE ROW'S AND UNDISTURBED AREAS THAT NEED NO RECLAMATION.
L . G . EVERIST , INC EXHIBIT AD-5
FIRESTONE GRAVEL RESOURCE
OPTION #2 - FILLED RESERVOIRS ••-•'+
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EXHIBIT L RECLAMATION COSTS (Revised 8/26/10)
This reclamation cost estimate in based on the assumption
that no more then 95 acres will need some form of reclamation at
any one time . Of this 95 acres, 5 . 0 would be roads, 7 . 54 acres
is a fresh water pond and the remaining 82 . 46 acres would be
stripped, partially mined or partially reclaimed area . The total
potential water area would be 26 . 04 acres . There will also be 3
acres, 8 foot deep in the settling pond area needing backfilling .
In this estimate we would have to complete bank backfilling and
compacting on 4650 linear feet at 47 . 41 cyd/linear ft . This
estimate is based on Option 1 of the Addendum to the Reclamation
Plan filed with Adequacy Letter #2 . In that option the lined
area will not be filled with water the entire site would be
revegetated. This means that 100 , 027 cubic yards of topsoil
would need disturbed on the reservoir areas, and seed beds . We
would also have to grade and shape 90 acres of seed bed area and
revegetate 90 ac . ± . The amount of topsoil that will be re-
spread is based on an average of 8 inches . The revegetation cost
figure includes fertilizer, grass seed, mulch and drilling costs .
We have included the cost to demolish 100 yards of concrete
foundations of the Concrete and Asphalt plants, a scale/scale
house and the processing plant .
A 627C Cat motor scraper or similar equipment will be used
to resoil the area and a 140G Cat motor grader or similar equip-
ment will be used to shape the seed bed, the resoiled areas and
rip the plant site . A D8N Cat dozer or similar equipment will be
used to reconstruct the compacted liner on the perimeter of the
lake areas . A Cat 988B loader or similar equipment is used to
transport fill to the settling pond area .
We have included a factor of 20% for the Division to do
remedial work on the completed liner if SEO certification is not
accomplished. We also rounded the pumping time to the next day
and used 72 , 300 gal/day as a transmissivity number to figure
inflow from the aquifer . These figures are then used in the
calculations for the bond amount . The tables below outlines the
various areas of disturbance at that the time describe3d above .
RECLAMATION ACTIVITY AREA(UNITS AC.,LFT,YDS OR PIECES)
Mining Plant Settling TOTALS
areas site pond
area
RESOIL (ac) 55.00 32.00 3.00 90.00
REVEGETATE (ac) 55.00 32.00 3.00 90.00
DEWATER (ac) 18.50 7.54 0 26.04
LAKE SLOPE CONSTRUCTION (Lft) 2,000 2650 0 4,650
LAKE SLOPING COMPLETE (Lft) 1,800 0 NA 1,800
LAKE AREA (ac) 18.50 7.54 0 26.04
CONCRETE DEMOLITION (yds) 0 100 0 100.00
ROADS (ac) 2.87 1.27 .86 5.00
1
EXHIBIT L RECLAMATION COSTS (cont}
DATA
EXPLANATION QUANTITY UNITS
Soil depth 8.00 Inches
Lake bank sloping complete 1800 Lft
Lake bank slope reconstruction 4650 cy/Lft
Bank Slope reconstruction time 84.85 days
Weed control costs $5,000.00 Per year
DEWATERING DATA
Description AMOUNT UNITS
Area 100% of lake depth 18.75 acres
maximum depth 26.00 feet
length of 3:1 slopes 1,800 feet
length of 1/2:1 slopes 4,650 feet
Unit volume of water on 3:1 slopes 1,014.00 cft/Lft
Unit volume of water on 1/2:1 slopes 169.00 cft/Lft
Gallon conversion factor 7.48 gal/oft
Transmissivity# 72,300 gal/day
Pump rate minimum 6,000 gpm
CALCULATED VOLUMES AND TIMES
Slope water volumes
3:1 slope capacity 13,652,496 gal
/ :1 slope capacity 5,878,158 gal
100% depth 171,586,350 gal
Total pumping volume 191,117,004 gal
Pumping time
Dewater lake 20.26 Days
Slope construction time 84.85 Days
Recharge factor for inflow during slop- 0.88 Days
ing time and Dewatering
TOTAL PUMPING TIME* 106.00 Days
*NOTE: pumping time rounded to next full day
2
EXHIBIT L RECLAMATION COSTS (cont)
ESTIMATED UNIT COSTS FOR RECLAMATION ITEMS:
Unit Cost
1 . Revegetation includes grass seed mix, mulch
and fertilizer and labor to drill $500 . 00/AC .
2 . Re-spreading soil and/or growth media with
627-E Motor Scraper, Haul distance less than 900 . . . 55 . 2 /YD3
3 . Rip seed bed in plant site, 140G motorgrader . . $60 . 63/ac .
4 . Grade and shape seed beds, 140G motorgrader . $59 . 54/ac
5 . Pumping costs includes, full service rental
of self contained pump, fuel, maintenance
and servicing daily. $166 . 67/day**
6 . Backfill side slopes, D8N Dozer push distance less
than 250 feet 63 . 7 /YD3
7 . Backfill settling pond area 988B LoaderHaul
distance less than 900 feet 72 . 0 /YD'
8 . Demolition & on-site disposal $7 . 00/Yd.
9 . Secondary Revegetation seeding only $500 . 00/ac
RECLAMATION COSTS
1 . Revegetation, 90 . 00 ac @ $500 .00/ac $44 , 997 . 50
2 . Resoiling, 96, 795 yd' x 1 . 12 @ 55 .2 /yd3 59, 842 . 54
3 . Rip plant site 32 . 00 ac @ $60 .63/ac . 1 , 940 . 16
4 . Grading and shaping 03 .00 ac. @ $59 .54/ac 5, 358 . 60
5 . Dewatering, 106 days @ $166 .67/day 17, 666 . 67
6 . Backfill and compact slopes
slopes, 220, 456 yd3 x 1.15 @ 63 .7 /yd' 161, 493 . 43
7 . Backfill Settling Pond 38, 720 Cy x 1 .12 @ 72 . 0 / yd 31 , 223 . 52
7 . Demolition & on-site disposal 100 yds@ $7 . 00/Yd. 700 . 00
8 . Secondary revegetation 90 . 0 ac x 25% x $500 .00/ac 11, 250 . 00
9 . Contingency fund for completed slopes
1800 Liner ft @ 47 .41 yd/lft * 63 .7 / yd * 20% 10 , 872 . 06
10 . Weed control costs 5, 000 . 00
Net Total $350 , 346 .48
11 . Indirect costs
Mobilization 3 , 574 . 14
Insurance, Bond, & Profit 47 , 366 . 89
12 . Administration costs 19 , 885 . 67
TOTAL ESTIMATE $421 , 173 . 16
RECOMMEND BOND BE SET AT $421,000.00
Equipment listed in this estimate is used for the calculations and similar types may be used in the
actual reclamation activities at the mine.
Source of figured using, Cat Handbook #38 and rental costs from Means for 83% efficiency, for eastern
Colorado
** Estimate for services from Rain for Rent, Ft. Lupton, CO (970) 535-4963
3
Notes:
1 . Locations of stockpiled materials may vary from those shown on this map.
2. Operator will maintain enough material on hand to complete reclamation ! ���\k�' _�_-----
as described in the Reclamation Plan. ___1 saws ~��
I
3. 18.00 acres of additional water surface would result if dewatering ceased i%
in the active mining area shown on this map. \�~� •
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' a L . G. EVERIST, INC .
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►ELSC24 a. GAS/OIL WELL ,�, e,ry�
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DATE: DECEMBER 25. 2009
a. SCALE: 1 'm350'
PROJECT MANUAL
FIRESTONE GRAVEL RESOURCE
SLOPE LINER
Prepared for:
L.G. EVERIST
Mountain Division
7321 East 88th Avenue, Suite 210
Henderson, Colorado 80640
D&A Job No. CG-0201.011.00
July 2010
DEERE & AULT
CONSULTANTS, INC.
600 South Airport Road, Suite A-205
Longmont,CO 80503
(303)651-1468 • Fax (303)651-1469
PROJECT MANUAL
FIRESTONE GRAVEL RESOURCE MINE SLOPE LINER
TABLE OF CONTENTS
DESIGN MEMORANDUM
TECHNICAL SPECIFICATIONS
Division 1 - General Requirements
Section 01070 - Abbreviations, Symbols and Definitions
Section 01400 - Quality Control
Division 2 - Site Work
Section 02140- Dewatering
Section 02230 - Base Course
Section 02290 - Embankment Slope Liner Construction
FORMS
Firestone Gravel Resource Mine Slope Liner Foundation Check Off Sheet
Summary of Field Density Tests
DRAWINGS
Firestone Gravel Resource Mine- Typical Slope Liner Cross Section
ATTACHMENT A
Slope Stability Results in Graphical Format
P'.A0201 IA EveretA020 I Oi l Firestone Gravel Resource MlneAPrajecI Manuanhojecl Manual TOG Doc
DESIGN MEMORANDUM
DEERE & AULT
CONSULTANTS,INC..
MEMORANDUM
TO: Matt Noteboom, L.G. Everist
FROM: Scott Palmer and Roy Spitzer, Deere & Ault Consultants, Inc.
DATE: July 23, 2010
RE: Firestone Site, Slope Liner Design; D&A Job No. CG-0201.011.00
As per our proposal dated May 11, 2010, we provided engineering services for the design of a
slope liner at the Firestone Resource Site located near Firestone in Weld County, Colorado. As
part of these services we reviewed the available project data, developed parameters for design,
and prepared a project manual. Following mining, the aggregate mine may be reclaimed as a
below grade water storage reservoir. The project manual includes select construction documents
for the design consisting of a technical memorandum, technical specifications for the
embankment construction, forms for documenting the construction, and a typical cross-section
for the slope geometry analyzed. The goal of these engineering services is to provide general
guidance in mine reclamation to support permit acquisition, and provide a general plan for
reclamation following mining. These documents do not include a site specific grading plan,
specific cross-sections, stationing, or complete reservoir design.
PURPOSE OF DESIGN
The goals for this engineering project include:
1. Design a compacted soil embankment slope liner section calculated to meet leakage
design standards as set forth by the Colorado "State Engineer Guidelines for Lining
Criteria for Gravel Pits," August 1999.
2. Design of a reclamation slope using site soils, which will meet or exceed the minimum
standards set by the DRMS for reclaimed gravel pits and which are calculated to provide
suitable factors of safety for stability over typical range of reservoir operating conditions.
To accomplish these design goals, the analysis of the soil embankment slope liner included slope
stability. This letter summarizes the results of the analysis. Below we present a brief
background and the results of our findings.
Although a site specific seepage analysis was not performed, the design delineated in this project
manual is based on experience with similar projects and a properly constructed slope liner
embankment based on the guidelines provided in this manual should meet the SEO guidelines for
600 S.Airport Road,Building A,Suite 205
Longmont,CO 80503
Phone: 303-651-1468• Fax: 303-651-1469
lined gravel pits. As mining progresses the bedrock in particular should be evaluated for seepage
potential considering the assumptions made for this design.
BACKGROUND
The site is located near Firestone in Weld County, Colorado, immediately north of Weld County
Road (WCR) 26 and east of WCR 15. The Firestone Resource Mine Site is currently not active
and is in the permit application process. Construction of a compacted soil embankment slope
liner is proposed to be completed inside the mine highwall during mining as slope areas are
exposed and the mining proceeds.
We have based our analysis on preliminary data regarding the typical soil profile at the site on
data provided by the client.
SOIL CONDITIONS
The preliminary data identified approximately 5 feet of overburden soils above the gravel
resource consisting mainly of clays. This overburden was generally underlain by approximately
26 feet of medium dense to very dense sand and gravel. An intermediate sandy clay to clayey
sand layer mud lens in the sand and gravel was not mentioned in the preliminary data. Because
this mud lens layer was not present, our analysis considered the sand and gravel layer to be
continuous. Beneath the sand and gravel the bedrock in the area is expected to consist of sandy
siltstone or silty sandstone identified on regional mapping as the Fox Hills Sandstone Formation.
Static groundwater was observed to be approximately 7 feet below the ground surface. For the
purposes of our analysis it was assumed to be 7 feet below the ground surface.
STABILITY ANALYSIS
Our stability analysis involved generating a computer model of limit equilibrium analysis using
the Slope/W computer program. Table 1 summarizes the parameters of the soils used in the
model.
Table 1: Model Parameters
Effective Friction Effective Moist Unit Weight
Soil type Angle, 0'(degrees) Cohesion, c'(psf) y,(pcf)
Overburden 27 25 110
Sand and Gravel 34 0 115
Bedrock 26 700 126
Weathered Bedrock 24 0 126
Slope liner Zone lA(core) 26 150 115
Slope liner Zone 1B (shell) 30 100 118
Stability Berm 26 50 122
These parameters are based on similar soils from other projects in the area and engineering
judgment. Based on comparison with published data (Table 1, Typical Properties of Compacted
Soils, DM-702, Foundations and Earth Structures, Naval Facilities Engineering Command,
- 2 -
1986), the strength parameters used for the compacted liner soils are reasonable and
conservative. We have assumed the liner soils will be compacted to at least 95 percent of
Standard Proctor density at or near optimum moisture content.
Our stability analysis involved modeling the slope liner configuration and evaluating the factor
of safety and failure surface orientation. Shallow surfaces (infinite slope or "raveling failures")
were excluded from the analysis, as they should not impact the overall performance of the slope
liner.
The data provided suggest, the soil conditions are generally uniform across the site. For our
analysis, the model incorporated one typical soil profile. This profile consisted of a 5-foot thick
layer of clayey overburden soils, underlain by a 26-foot thick layer of sand and gravel. A 2-foot
thick weathered bedrock layer was incorporated into the model 31 feet below the ground surface.
Then firm bedrock was modeled below a depth of 33 feet.
A 3:1 (horizontal to vertical) slope was initially analyzed. The slope geometry and configuration
are shown in the Drawing section of this Project Manual.
Four cases were analyzed for the slope configuration: an as-constructed or before water storage
case, a rapid drawdown case, a full reservoir case, and a full reservoir with earthquake loading.
For the rapid drawdown case, the shell was not considered free draining, but a thin layer of slope
protection material was considered to be free draining. Therefore, for this case phreatic surface
was raised to just below this free draining material. A pseudo-static horizontal acceleration
coefficient of 0.1 g was used to determine earthquake loading for the full reservoir with
earthquake case.
Table 2 summarizes the results of our stability analysis. Output graphics for each of the analyses
are provided in Attachment A of this Project Manual. The factors of safety required by the State
Engineers Office (SEO) for these same loading conditions on above-grade embankment dams are
listed for comparison. Considering that the consequences of failure are less for a below-grade
slope liner than for a dam, lower factors of safety may be acceptable. However, the factors of
safety for the 3:1 slope met or exceeded the SEO criteria for each case.
Table 2: Deep Seated Failure Analysis Results
Full Reservoir with
Model As-Constructed Case Rapid Drawdown Full Reservoir
Earthquake
Geometry and Model SEO Dam Model SEO Dam Model SEO Dam Model SEO Dam
Mode of Factor of Factor of Factor Factor of Factor Factor of Factor Factor of
Failure Safety Safety of Safety Safety of Safety Safety of Safety Safety
3:1 (h:v) 2.1 1.5 1.3 1.2 2.4 1.5 1.4 1.0
SUMMARY AND RECOMMENDATIONS
The stability models predict suitable factors of safety for 3:1 (horizontal to vertical) liner
geometries. A toe berm may be locally required for site specific conditions where thick mud
- 3 -
lens or other adverse conditions are encountered. We understand you plan to construct the
embankment slope liner using 3:1 (horizontal to vertical) slopes.
The soils and bedrock on the project site appear suitable to the goals of the project if placed and
compacted properly. We recommend you plan for quality control testing on a regular basis to
help ensure the liner soils are placed and compacted in accordance with the design specifications.
Care should be taken to avoid lamination between lifts of liner soils or at the bedrock soil
interface. We recommend that soils to be placed in embankment are compacted with a kneading
action compactor such as a sheepsfoot compactor to reduce the risk of lamination. Additionally
we recommend that the foundation and cut-off key trench should be wetted and rolled with a
sheepsfoot to improve bonding between the bedrock and the first lift of embankment soils.
LIMITATIONS
The design in this memo is based on the soil information provided. During mining if
significantly different conditions are encountered such as mud lenses, deeper bedrock or weak
soils we should be contacted to evaluate the need for further analysis. Depending upon the
conditions encountered in the mine highwalls, site specific stability analysis, seepage analysis,
and other analyses and design layout efforts may be required to develop final reclamation slopes
around the mine perimeter.
If you have questions regarding our design assumptions or these analyses, please feel free to call.
P.A11201 LO Esensi 0201 011 Firestone Gravel Resource MineNmject ManualSdesign memoAFirestone MEMORANDUM dose
- 4 -
TECHNICAL SPECIFICATIONS
Division 1 - General Requirements
•
DIVISION 1 - GENERAL REQUIREMENTS
SECTION 01070-ABBREVIATIONS,SYMBOLS AND DEFINITIONS
1.01 ABBREVIATION AND SYMBOLS
Wherever used in these Specifications,the following abbreviations shall have the meanings indicated:
AASHTO American Association of State Highway and Transportation Officials
AISC American Institute of Steel Construction
ANSI American National Standards Institute
API American Petroleum Institute
ASME American Society of Mechanical Engineers
ASTM American Society for Testing and Materials
CDOH Colorado Department of Highways
COSH Colorado Occupational Safety and Health Standards Board
CRSI Concrete Reinforcing Steel Institute
OSHA Occupational Safety and Health Administration
psi pounds per square inch
SEO State Engineer's Office
Where standard specifications are referenced in the Contract Documents,the latest revision is intended
unless specified otherwise.
1.02 DEFINITIONS
The project entities and personnel shall be defined as follows:
Miner-L.G. Everist
Mine Owner-L.G. Everist
Mine Operator-L.G.Everist
Contractor-L.G. Everist or subcontractor
Mining Superintendent- Roger Servold (L.G.Everist)
Project Engineer-Jim Sittner or Matt Noteboom(L.G. Everist)
Design Engineer-Deere& Ault Consultants, Inc.
END OF SECTION
6/10 Section 01070-Page 1 of 1
DIVISION 1 - GENERAL REQUIREMENTS
SECTION 01400 - QUALITY CONTROL
PART 1 -GENERAL
1.01 TESTING
Quality control testing shall be performed at the testing frequency specified by the drawings and project
specifications. The Mining Superintendent shall be responsible for ordering the sampling and testing, and
for coordinating the testing efforts with the construction. The Mine Superintendent shall inform the Project
Engineer of ongoing work. The Project Engineer will notify the Testing Laboratory and Design Engineer
of necessary quality assurance work.
A. Location Identification Requirements
The location (horizontal and vertical position)of all earthfill moisture/density tests shall be
recorded by the soils testing technician. The test location shall be identified by means of a hand
held GPS unit. The location shall be located to a degree of accuracy of 20' horizontally. The GPS
unit shall be calibrated to a local benchmark each day prior to testing and more frequently if
warranted by changes in weather to correct any weather induced drift in the unit. Vertical position
shall be recorded by referencing local reference staking established adjacent to the work area.
The soils testing firm will provide an as-built map depicting the test points with the test reference
number. The test reference number shall match the numbering system used by the soils testing
firm in their tabular listing of test results. This as-built map shall be updated annually and 3
copies submitted to the Mining Superintendent, who will forward 1 copy to the Project Engineer
and 1 copy to the Design Engineer(Deere&Ault Consultants, Inc.).
1.02 OTHER TESTING
If required by the Engineer, the following testing shall be performed:
A. Material Substitution
Any tests of basic material or fabrication equipment offered as a substitute for specified item on
which a test may be required in order to prove its compliance with the specifications.
B. Non-Specialized Fill Material
Materials in the embankment fill which are not specified by the drawings or technical
specifications shall be approved for use by the Engineer prior to placement. Such material may
include granular drainage material to control groundwater,riprap or riprap bedding material, or
random fill adjacent to the limits of the embankment fill materials. Prior to approving such
material for use,the Engineer may require specific testing be performed and the test results
provided for review. Quality control testing of the placed materials may also be required.
1.03 TEST REPORTS
Reports of all tests made by testing laboratories shall be delivered in triplicate by the testing laboratory to
the Mining Superintendent who will distribute them as follows:
1 copy-Mining Superintendent
1 copy-Project Engineer
I copy-Design Engineer
Other copies -As directed
6/10 Section 01400-Page 1 of 2
1.04 QUALITY CONTROL SYSTEM
A. General
The Mining Superintendent's quality control system is the means by which he assures
himself that his construction complies with the requirements of the contract documents. Controls
shall be adequate to cover all construction operations and shall be keyed to the embankment slope
liner construction schedule.
B. Records
The Mining Superintendent shall maintain correct records on an appropriate form for all
inspections and tests performed, instructions received from the Design Engineer and actions taken
as a result of those instructions. These records shall include evidence that the required inspections
or tests have been performed(including type and number of inspections or tests, nature of defects,
causes for rejection,etc.), proposed or directed remedial action,and corrective action taken. The
Mining Superintendent shall document inspections and tests as required by each section of the
specifications. A file containing the testing records shall be maintained in the Mining
Superintendent's site office. These records shall be updated daily or as required based on the pace
of construction. The records will be available to the Project Engineer and Design Engineer for
review during their site visits.
PART 2-NOT USED
PART 3-NOT USED
END OF SECTION
Section 01400-Page 2 of 2 6/10
Division 2 - Site Work
•
DIVISION 2 - SITE WORK
SECTION 02140 - DEWATERING
PART 1 -GENERAL
1.01 WORK INCLUDED
Furnish all labor,tools,equipment,permits,and perform all work and services necessary for controlling
groundwater and surface water, and associated dewatering requirements to provide a dry and stable
working area for all construction activities on-site. L. G. Everist shall be responsible for obtaining any
required dewatering permits and comply with all applicable federal, state, and local regulations.
1.02 RELATED WORK
A. Section 02290-Embankment Slope Liner Construction
1.03 REFERENCES (NOT USED)
1.04 SUBMITTALS (NOT USED)
PART 2-NOT USED
PART 3-EXECUTION
3.01 GROUNDWATER
It is expected that dewatering will be required during construction of the slope liner.
The Mine Superintendent or designee shall provide for dewatering as required to provide for stability and
firmness for construction of the slope liner. The water table shall be lowered prior to construction to an
elevation to permit all construction operations to be performed in relatively dry conditions. The lowered
water level shall be maintained until such time as the work is sufficiently advanced to be secure from
damage caused by groundwater. In areas where compacted embankment is required,the excavation shall
be free of water prior to and during placement of soils.
Dewatering shall be accomplished to remove detrimental water from the work area. Acceptable methods
include the use of interceptor channels, coffer dams,pumps, well points, and sump pumps. Use of rock or
gravel drains placed below subgrade foundations, or subsurface pipe drains shall be reviewed on a location
specific basis by the project and design engineers. Noise from dewatering operations shall conform to all
applicable noise ordinances. All water shall be disposed of in a suitable manner without being a menace to
public health or causing a public inconvenience. No water shall be drained into other completed work or
areas under construction.
The dewatering operations shall continue until groundwater will not damage any construction items or
materials.
Any channels,flumes,drains, sumps, wells, walkway systems, and/or temporary diversion and protective
works necessary for dewatering the excavations shall be constructed and maintained by L.G. Everist. After
having served their purpose, all temporary drainage diversion structures, sumps, wells, and channels shall
be removed, leveled, or filled in a manner approved by the Engineer.
The Mine's operation shall conform to applicable federal, state,and local requirements of the National
Pollutant Discharge Elimination System(NPDES). L. G. Everist shall obtain all necessary permits and
conform to all permit requirements,including but not limited to, monitoring, measuring, sampling,
reporting, and maintaining a dewatering system.
7/10 Section 02140-Pagel of 2
•
3.02 SURFACE WATER
Controlling, routing, and storage of surface water and storm water shall be the responsibility of the L. G.
Everist. The Mining Superintendent shall be responsible for constructing and maintaining any temporary
channels,detention ponds, and dams. All surface water shall be controlled in a manner that prevents
damage to any constructed items, items being constructed,or any neighboring structures or facilities. The
water handling facilities shall prevent sediment transport onto neighboring properties. The storm water
control measures shall not cause an increase in flooding to downstream or adjacent properties.
L.G. Everist shall acquire any permits needed for handling surface waters during construction.
END OF SECTION
Section 02140-Page 2 of 2 7/10
•
DIVISION 2 - SITE WORK
SECTION 02230-BASE COURSE
PART 1 -GENERAL
1.01 WORK INCLUDED
Extent of base course is indicated on the Contract Drawings.
This section covers base course requirements for placement on the slope liner crest road.
1.02 RELATED WORK
Section 02290-Dam Embankment and Embankment Slope Liner Construction
1.03 SUBMITTAL
The Mine Superintendent or designee shall provide a base course sample to the soil testing laboratory for
determination of gradation and Standard Proctor density.
PART 2-MATERIALS
2.01 BASE COURSE MATERIALS
The base course shall consist of a hard,durable,crushed rock or stone and filler. The composite base
course material shall be free from vegetable matter and lumps or balls of clays and shall meet the Colorado
Department of Transportation Specification Class 6 Aggregate Base Course which follows:
Sieve Size % Passing
3/4" 100
#4 30 -65
#8 25 -55
#200 3- 12
Liquid Limit-30%Maximum
Plasticity Index-6%Maximum
Base course may be obtained and processed on-site.
PART 3-EXECUTION
3.01 ROAD BASE COURSE
The upper 12" of the subgrade shall be scarified and recompacted to a maximum of 95% Standard Proctor
Density per ASTM D698.
On-site material as approved by the Engineer, is suitable for compacted fill in proposed base course areas.
Fill in base course areas shall be placed within two percent of optimum moisture content and compacted to
a minimum of 95 percent Standard Proctor Density per ASTM D698.
The base course shall be placed on the subgrade within+/-two percent of optimum moisture and
compacted to at least 95 percent of Standard Proctor Density. The base course shall be graded and shaped
so that proper drainage of the crest road is obtained.
END OF SECTION
7/10 Section 02230-Page 1 of 1
•
DIVISION 2 - SITE WORK
SECTION 02290 - EMBANKMENT SLOPE LINER CONSTRUCTION
PART 1 -GENERAL
1.01 WORK INCLUDED
Construction of the embankment slope liner as shown on the detail drawings and as specified herein,
including foundation preparation,dewatering, fill placement, moisture control, and compaction.
1.02 RELATED WORK
A. Section 02140-Dewatering
PART 2-MATERIALS
2.01 COMPACTED EMBANKMENT SLOPE LINER
The embankment slope liner shall be constructed as zoned embankments in accordance with the detail
drawings. The majority of the embankments will be constructed with Zone I soils. The more clayey
material shall be placed in Zone IA, the central portion of the slope liner. The sandier material shall be
placed on the upstream slopes of the slope liner in Zone 1B. Since some soil property specifications for
Zone IA and I B overlap, many on-site soils will be suitable for either zone.
A. Embankment Zone IA
Zone IA will be constructed of clayey soils meeting the following criteria:
035 percent or greater passing the No. 200 sieve
°No more than 40%retained on the No. 4 sieve
°Minimum plasticity index of 12%
°Unified Soils Classification: CL, SC, SC-GC,CL-CH
Sources for Zone IA embankment soils may include the following on-site materials:
°Mud Lens
°In-place overburden
°Stockpiled overburden
°Clay fill
°Claystone bedrock with a liquid limit of less than 50
°Select zones of miscellaneous fill
The material shall be obtained from required excavations, borrow areas, or stockpiles. The soils
shall be free of any deleterious materials,including rocks larger than 5", as specified by the
Design Engineer. Oversize rock fragments shall be wasted as approved by the Design Engineer or
stockpiled for use in other zones when found to be acceptable to the Design Engineer.
B. Embankment Zone 1B
Zone IB will be constructed principally of material meeting Zone IA requirements or compacted
clayey sand soils meeting the following criteria:
°Between 18 to 55% passing the No. 200 sieve
°No more than 60% retained on the No.4 sieve
°Unified Soils Classification: CL, SC. CL-SC, GC, SC-GC, SM-SC, GM, GM-GC
6/10 Section 02290-Page I of 6
Sources of Zone 1B embankment soils may include the following on-site materials:
°Mud lens
°In-place overburden
°Stockpiled overburden
°Clay fill
°Select zones of miscellaneous fill
The material shall be obtained from required excavations, borrow areas, stockpiles,or other
sources as specified by the Design Engineer. The soils shall be free of any deleterious materials,
including materials larger than 5", as specified by the Design Engineer. Oversize rock fragments
shall be wasted as approved by the Design Engineer or stockpiled for use as riprap when found to
be acceptable to the Design Engineer.
C. Embankment Zone 2
Zone 2 will be constructed of a clayey gravel soil meeting the following criteria:
Sieve Size Percent Passin?
7" 100
1-1/2" 70-95
No. 4 45-80
No.200 14- 30
°No less than 70% passing the 11/2"sieve
°Unified Soils Classification: GC, GC-SC
Zone 2 shall be a well graded mixture of 12"of sand,gravel, and cobbles left behind from mining
operations and 6" of weathered claystone bedrock. Where the gravel and cobble layer is less than
12", additional pit run will need to be added.
2.02 EMBANKMENT MATERIALS SUMMARY
Minimum
Minimum
Placement
Construction Unified Soils Class and Testing Testing
Zone Requirements Compaction Requirements Interval
Requirements
Zone lA CL, SC, SC-GC,CL-CH 95%of ASTM Density by nuclear Each 1,000 yds3
D698 gage.ASTM D2922*
Minimum PI= 12%
-200 sieve, ASTM Each 10,000 yds3
35% or greater passing the D1140
No. 200 sieve
Atterberg limits, Each 10,000 yds3
No more than 40%retained ASTM D4318
on the No.4 sieve
Zone 1B CL, SC,CL-SC, GC, GC-SC, 95% of ASTM Density by nuclear Each 1,000 yds3
SM, SM-SC, GM, GM-GC D698 gage, ASTM D2922*
18 to 55% passing the No. Atterberg limits, Each 10,000 yds3
200 sieve ASTM D4318
No more than 60% retained
on the No.4 sieve
Section 02290-Page 2 of 6 6/10
Minimum
Minimum
Placement
Construction Unified Soils Class and Testing Testing
Zone Requirements Compaction Requirements Interval
Requirements
Zone 2 GC, GC-SC 95% of ASTM Density by nuclear Each 1,000 yds3
D698 gage, ASTM 2922*
Sieve analysis, ASTM Each 10,000 yds3
D1163
*Note:The design engineer may request sand cone density tests(ASTM D1556)to calibrate the nuclear
density gage as required during the course of the quality control activities.
PART 3-EXECUTION
3.01 GENERAL
No material shall be placed in any portion of the embankment until the foundation for each section has
been dewatered, stripped, suitably prepared, and has been approved by the Design Engineer.
All cavities,depressions and irregularities, within the area to be covered by embankment and which extend
below or beyond the established lines of excavation for slope liner embankment foundations, shall be filled
with embankment materials as specified for the overlying embankment.
3.02 FOUNDATION PREPARATION
A. Mine Highwall Slopes
The mine highwall slopes shall be excavated to the lines and grades as shown on the detail
drawings.
Highwall overhangs shall be sloped back. Loose slough shall be removed prior to placement of
embankment soils. Loose or slough soils on the slope may be removed as the embankment soils
are being constructed.
B. Removal/Stripping of Weathered Bedrock
The weathered bedrock shall be stripped to a depth of 2' beneath the Zone 1A/Weathered contact.
The weathered bedrock will not need to be stripped beneath the Zone 1B/Weathered contact.
Care shall be taken that slabs of bedrock are not dislodged during the foundation bedrock stripping
process that increase the bedrock excavation depth beyond 2'. Shallower passes with excavating
equipment may be required during stripping to prevent slab dislodging along bedding planes.
Where claystone is encountered:
The entire foundation shall be watered,rolled and compacted to provide a suitable, non-
planar bonding surface for the first lift of embankment soil. Claystone foundation shall
be covered with slope liner fill soon after preparation to prevent drying and desiccation of
bedrock foundation.
Where excavations met with refusal (e.g. Sandstone material):
The entire foundation shall be cleaned of loose material prior to placement of the first lift
of embankment soil.
6/10 Section 02290-Page 3 of 6
•
C. Cutoff Trench
The cutoff trench shall extend at least 3' below the foundation surface measured after the
weathered or top 2' of bedrock is removed.
Where claystone is encountered:
After excavation the trench shall be watered,rolled and compacted to provide a suitable
bonding surface for the first lift of embankment soil. Claystone foundation shall be
covered with slope liner fill soon after preparation to prevent drying and desiccation of
bedrock foundation.
Where excavations met with refusal (e.g.Sandstone material):
The cutoff trench shall cleaned with a blade(such as a dozer blade). The bottom and
sides of the cutoff trench shall be suitably cleaned before embankment soil placement.
The Design Engineer or representative of the Design Engineer shall make the final determination
the method of foundation or cutoff trench bottom preparation.
3.03 STRIPPING
The entire area to be occupied by the embankment shall be stripped to a sufficient depth, as determined by
the Design Engineer,to remove all unsuitable materials. The unsuitable materials to be removed by
stripping shall include all surface boulders and loose rock,debris,topsoil, vegetable matter, including
stumps and roots, and all other perishable and objectionable materials that are unsuitable for use in
permanent construction required under these Specifications or that might interfere with the proper bonding
of the embankment with the foundation or the proper compaction of the materials in the embankment, or
that may be otherwise objectionable as determined by the Design Engineer.
3.04 PLACING CUTOFF TRENCH AND EMBANKMENT MATERIALS
The suitability of each part of the foundation for placing embankment materials thereon, and of all
materials for use in embankment construction, will be determined and approved by the Design Engineer.
No embankment material shall be placed in the embankment when either the material or the foundation or
embankment on which it would be placed is frozen.
In any separate portion of cutoff trench or embankment being constructed, each layer of each zone shall be
constructed continuously and approximately horizontal for the width and length of such portion at the
elevation of the layer. If transverse slopes are required in the cutoff trench or embankment, slopes shall be
no steeper than 4:1 (horizontal to vertical).
The Contractor shall maintain the cutoff trench and embankment in an approved manner, including
maintaining working surfaces free of weeds and other organic matter until final completion and acceptance
of all the work under the contract.
If,in the opinion of the Design Engineer,the surface of the prepared foundation or the compacted surface
of any layer of earthfill is too dry or smooth to bond properly with the layer of material to be placed
thereon,it shall be moistened and/or worked with harrow, scarifier, disc, or other suitable equipment, in an
approved manner to a sufficient depth to provide a satisfactory bonding surface before the next succeeding
layer of earthfill material is placed. If in the opinion of the Design Engineer, the compacted surface of any
layer of the earthfill in-place is too wet for proper compaction of the layer of earthfill material to be placed
thereon, it shall be removed,allowed to dry;or be worked with harrow, scarifier,disc, or other suitable
equipment to reduce the moisture content to the required amount; and then it shall be recompacted before
the next succeeding layer of earthfill material is placed.
Section 02290-Page 4 of 6 6/10
•
The Contractor shall be permitted to construct separate sections of the cutoff trench and embankment,
subject to the approval of the Design Engineer. Construction of the cutoff trench and embankment shall be
subject to the following conditions:
A. Longitudinal bonding surfaces(surfaces parallel to the centerline crest of embankment) between
previously constructed embankment and embankment to be constructed shall not be steeper than
2:1.
B. At any cross-section,the difference in elevation between adjacent zones of the embankment shall
be not greater than 3 feet,unless approved by the design engineer.
C. Transverse bonding surfaces (surfaces perpendicular to the centerline crest of the embankment)
shall not be steeper than 4:1.
During construction of new earthfill,the Contractor shall adequately prepare the surface of previously
constructed embankment zones, original embankment and transverse slopes by benching and/or scarifying
in a manner acceptable to the Design Engineer to satisfactorily bond the new fill to the existing fill.
3.05 MOISTURE AND DENSITY CONTROL
A. Cutoff Trench and Compacted Embankment Fill
The Standard Optimum Moisture Content is defined as"that moisture content which will result in
a maximum dry unit weight of the soil when subjected to the Standard Proctor Compaction Test as
described by ASTM D698." Material represented by the samples tested having a placement
moisture content less than two percent below standard optimum condition or more than two
percent wet of the standard optimum condition will be rejected and shall be reworked until the
moisture content is between these limits. Additional moisture as required in the opinion of the
Design Engineer may be applied by sprinkling on the cutoff trench or embankment fill soils.
Each layer of earthfill material shall be compacted as indicated in these specifications. During
compaction,the placement moisture content and dry density of the earthfill shall be maintained
within the control limits specified in each section.
To determine that the moisture content and dry density requirements of the compacted earthfill are
being met, field and laboratory tests will be made at intervals on samples taken at cutoff trench
and embankment locations determined by the Mine Superintendent subject to approval by the
Design Engineer. Density testing shall be by nuclear density gage. The results of all completed
earthwork tests will be available to the Design Engineer within one hour for nuclear density tests
and 24 hours for sand cone tests.
Materials not meeting the specified moisture content and dry density requirements, as determined
by the tests, shall be reworked until approved results are obtained. Reworking may include
removal, rehandling,reconditioning,rerolling, or combinations of these procedures.
The moisture content of the earthfill material prior to and during compaction shall be distributed
uniformly throughout each layer of the material. As far as practicable,the materials shall be
brought to the proper moisture content by adding supplementary water, if required,to the material
by sprinkling on the earthfill and each layer of earthfill shall be conditioned so that the moisture is
uniform throughout the layer.
Density control of compacted earthfill shall be such that the dry density of the compacted material,
as determined by tests performed by the Design Engineer, shall conform to not less than 95%of
its Standard Proctor maximum dry density. Material which does not meet these requirements will
be rejected and shall be reworked until a dry density equal to or greater than these requirements is
reached.
6/10 Section 02290-Page 5 of 6
•
3.06 PLACING AND COMPACTING
A. Cutoff Trench and Compacted Embankment Fill
The earthfill material shall be placed in the embankment in continuous and approximately
horizontal layers, not more than 9"loose lift thickness. The combined excavation and placing
operations shall be such that the materials will be sufficiently blended to secure the best
practicable degree of compaction and stability. To achieve sufficient blending, a disc,plow, tilted
blade, or other method approved by the Design Engineer will be required during placement of any
embankment fill.
The material shall be compacted to a minimum of 95% of the Standard Proctor as described in
ASTM D698. The method of compaction shall be submitted to the Design Engineer for approval.
Equipment for compacting and zone 1A, 1B, and 2 shall be capable of effectively achieving the
required density for the entire depth of the lift being placed as well as providing a suitable bonding
surface between lifts.
When each layer of material has been conditioned to have the specified moisture, it shall be
compacted with a vibrating sheepsfoot roller. The compacted density shall be essentially uniform
throughout the layer.
C. Upstream Slope Liner Face
The upstream slope liner face shall be cut to the lines and grades shown on the detail drawings.
After the upstream embankment is brought to final grade, the slope shall be compacted and
finished by"tracking"a D-9 Caterpillar(or approved equal)bulldozer up and down the slope.
END OF SECTION
Section 02290-Page 6 of 6 6/10
FORMS
FIRESTONE RESOURCE MINE SLOPE LINER
Foundation Check Off Sheet
Date
Dam Station
Yes No
Pre-Survey Complete
Bedrock Stripped
(where required)
Wet Bedrock Removed
Foundation Rolled with
Sheepsfoot
Post-Survey Complete
Comments
Sketch:
L.G. Everist
Deere & Ault Consultants
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STATE OF COLORADO
DIVISION OF RECLAMATION,MINING AND SAFETY
Department of Natural Resources
1313 Sherman St.,Room 215 CO LO RA D O
Denver,Colorado 80203 DIVISION OF
Phone:(303)866-3567 RECLAMATION
FAX:(303)832-8106 MINING
-&-
SAFETY
Bill Ritter,Ir.
Governor
James B.Martin
Executive Director
April 30,2010 Loretta E.Pineda
Director
Steve O'Brian
Environment Inc.
7985 Vance Drive#205A
Arvada, CO 80003
Re: Second Review of a 112 Construction Materials Reclamation Permit Amendment Application Package
AM-01,Firestone Gravel Resource,Permit No.M-1996-052
Dear Mr. O'Brian:
The Division of Reclamation, Mining, and Safety has completed its review of your responses to the initial adequacy
questions for the 112 construction materials reclamation permit amendment application. Although many questions
have been sufficiently resolved,the Division feels that clarification is still required on a few remaining points. The
decision date for this application is currently May 7, 2010. Please be advised that 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
will deny this application. In order to allow the Division adequate time to review your responses to any
adequacy issues, please submit your adequacy responses to the Division no later than one week prior to the
decision date.
Please note that any changes or additions to the application on file in our office must also be reflected in the public
review copy,which has been placed with the Weld County Clerk and Recorder.
APPLICATION FORM: Adequate as submitted
EXHIBIT A-Legal Description(Rule 6.4.1): Adequate as submitted
EXHIBIT B-Index Map(Rule 6.4.2): Adequate as submitted.
EXHIBIT C-Pre-mining and Mining Plan Map(s)of Affected Lands(Rule 6.4.3):
The Division understands that the locations and configuration of some future structures(such as concrete batch
plant and conveyor belts) is not currently known,and that it will be several years before they are constructed on
site. A Technical Revision will be required at a later date to add any of these structures/features and provide
details not specifically included at this time. Also be aware that placing structures of any kind, including
excavations and reservoirs, in the designated flood plain will be subject to approvals from Weld County and
FEMA(conditional letter of map revision,etc.) There will also be bonding implications for the removal of any
structures placed on-site.
O Office of
Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines
Portions of the site lie within the 100 yr flood plain of the St Vrain. Any excavations created that intersect the
flood plain will need to have armored inlet-outlet structures appropriately sized and placed to allow floodwaters
to enter and exit without damage. Please address this issue in the mining plan and show required features as
appropriate on the Mining and Reclamation Plan maps.
EXHIBIT D-Mining Plan(Rule 6.4.4): see previous paragraph.
Also be aware that placing structures of any kind, including excavations and reservoirs, in the designated flood
plain will be subject to approvals from Weld County and FEMA(conditional letter of map revision,etc.) It
seems likely, based on the configuration of the existing flood plain as shown on the provided FEMA map,that
the removal of the existing elevated rail-bed may have impacts on the extent of the flood plain that will also need
to be addressed as appropriate with Weld County and FEMA.
EXHIBIT E - Reclamation Plan (Rule 6.4.5): The Division understands that this property will now be
reclaimed primarily as compacted clay-lined dry excavations with rangeland vegetation. This differs
significantly from the original reclamation plan submitted which was primarily unlined open water lakes. It
would be appropriate under these circumstances to provide this "dry lined excavation" scenario as a primary
reclamation plan, with an alternative reclamation plan to fill the lined excavations as lakes if it becomes feasible
in the future for the operator to do so. This would allow either option(vegetated excavations or reservoirs)to be
implemented without the need for another permit amendment to modify post mining-land use. Appropriate
reclamation plans and maps and will need to be provided for both proposed scenarios.
EXHIBIT F-Reclamation Plan Map(Rule 6.4.6): Reclamation Map(s)will need to be updated to show flood
water inlet/outlet structures as required for excavations/reservoirs within the 100 yr flood plain.
EXHIBIT G-Water Information(Rule 6.4.7): Please provide the following information:
• The adequacy comments state that"LG Everist,Inc. proposes implementing corrective actions when
groundwater levels at the exterior monitoring holes have dropped 5 feet or more from the monthly
average drop established during monitoring." Specifically, which"exterior monitoring holes"does this
statement refer to? LG Everist should evaluate/consider if their current groundwater monitoring points
will be sufficient to defend them against claims of off-site impacts to the nearby wells.
• The change from unlined to compacted clay lined reservoirs also introduces the potential for
groundwater mounding/shadowing. There are currently no plans for a French drain or any other
mitigation against groundwater mounding/shadowing. Again, LG Everist should consider if their current
groundwater monitoring points will be sufficient to defend them against claims of off-site impacts from
this new configuration.
• Are there any downstream users of the"Seep Ditch"that have filed for water rights that would be
impacted by its removal on-site? Will removal of the "Seep Ditch"on-site impact irrigation return
flows?
EXHIBIT H-Wildlife Information (Rule 6.4.8): Adequate as submitted.
EXHIBIT I-Soils Information(Rule 6.4.9): Adequate as submitted.
EXHIBIT J-Vegetation Information (Rule 6.4.10): Adequate as submitted.
EXHIBIT K-Climate(Rule 6.4.11): Adequate as submitted.
EXHIBIT L-Reclamation Costs(Rule 6.4.12): The revised reclamation estimate provided is much better than
most, and the Division will accept the proposed method of dewatering cost calculation/estimate. The changes
proposed to the reclamation plan (clay liners, primary/secondary scenarios) may require some modifications to
the estimate breakdown to facilitate a phased approach. The statements in the submitted adequacy letter that
"resumption of mining is delayed for the next couple of years" and "We do not believe it is necessary to post a
large bond until just before we come out of temporary cessation" also will require some clarification. By Rule,
bond to cover reclamation of the existing disturbance (including the existing scale house, stockpile removal,
draining and resloping/lining of existing excavation, exposed surface water, revegetation, weed control, etc.)
should be in place now-regardless of the site's temporary cessation status. This site has an existing posted bond
of$49,450 and is currently under-bonded. In addition, the bond revision due to the expansion of activities in
this amendment will be due within 365 days from the date the Division approves the amendment unless the bond
is phased appropriately and stated as an enforceable condition in the amendment application.
To address these issues, the Division requires at a minimum (and as a suggested first phase of a phased
approach), adjusting the existing bond as appropriate to reclaim the existing disturbances. The second phase of
this approach could be to post adequate bond to cover the first phase of renewed mining activities as outlined in
this amendment immediately prior to bringing the site out of temporary cessation.
The Division understands that the excavated "lake" areas will now have a compacted clay liner to satisfy the
SEO requirements and may not, in fact, be filled prior to release. In order to qualify for the 20%bonding option
for a compacted clay liner, the operator will need to provide design specifications for the liner that satisfy, at a
minimum, the requirements of the clay backfill pit liners portion of the "Guide to Specification Preparation for
Slurry Wall and Clay Liners as a Component of a Colorado Mined Land Reclamation Permit" document dated
September 2000 and available on the DRMS web site.
Please also provide the linear feet of compacted clay liner that will be required for each excavated ("lake") area.
This will allow a much easier calculation of the bond required for each phase of the operation as well as facilitate
bond releases when any individual lined phase passes SEO testing.
EXHIBIT M-Other Permits and Licenses(Rule 6.4.13): Adequate as submitted.
EXHIBIT N-Source of Legal Right to Enter(Rule 6.4.14): Adequate as submitted.
EXHIBIT O- Owner(s) of Record of Affected Land(Surface Area)and Owners of Substance to be Mined
(Rule 6.4.15): Adequate as submitted.
EXHIBIT P-Municipalities Within Two Miles(Rule 6.4.16): Adequate as submitted.
EXHIBIT O-Proof of Mailing of Notices to County Commissioners and Soil Conservation District (Rule
6.4.17): Adequate as submitted.
EXHIBIT R-Proof of Filing with County Clerk and Recorder(Rule 6.4.18): Adequate as submitted.
EXHIBIT S-Permanent Man-Made Structures(Rule 6.4.19):
The Division has received proof that the operator has pursued agreements with all structure owners within 200'.
If additional agreements are executed by structure owners in the future, please forward copies to the Division for
inclusion in the site record.
•
Although not specifically required, it would likely be in the best interest of LG Everist to renew old agreements with
existing structure owners that have been carried forward from the previous permittees(Encana,Last Chance Ditch).
This concludes the Division's second adequacy review of this application. Other issues may arise as additional
information is supplied. Please remember that the decision date for this amendment application is May 7, 2010. As
previously mentioned,if you are unable to provide satisfactory responses to any inadequacies prior to this date, it
will be your responsibility to request an extension of time to allow for continued review of this application. If
there are still unresolved issues when the decision date arrives and no extension has been requested, the
application will be denied. If you have any questions,please contact me at(303) 866-3567 x8140.
If you wish, I would be happy to meet with you here at DRMS to discuss possible options, and what the best way to
address any of these issues may be.
Sincerely,
lietc „At
Eric Scott—Environmental Protection Specialist
LARGE MAPS AVAILABLE
FOR VIEWING
AT
THE CLERK TO THE
BOARD 'S OFFICE ,
IN THE
PUBLIC REVIEW FILE .
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