PERMFILE109046

• Permit No: M2000016
• IBM Index Class Name: Permit File
• Doc Date: 4/12/2000
• Doc Name: RESERVOIR LINER AND MINING SETBACKS MOBILE PRE MIX CONCRETE INC RIVERBEND PIT FN M-00-016
• From: DMG
• To: GREGG SQUIRE
• Media Type: D
• Archive: No

~ ~,~. iii iiiiiiiiiiiiiiii
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department o(Na(ural Resources
1313 Sherman 51., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
DATE: April 12, 2000
DIVISION O F
MINERALS
GEOLOGY
RECLAMATION
MINING•SAFETY
Bill Owens

TO: Gregg Squire Governor
Greg E Watcher
Executive Duedor
FROM: Allen Sorenson '~ ~ Michael R Long
1 Dimsion D~reaor
RE: Reservoir Liner and Mining Setbacks, Mobile Pre-Mix Concrete Inc.,
Riverbend Pit, File No. M-00-016
The following application adequacy items aze limited [o the Division's review of the portion s of the
application involving proposed mining setbacks and the installation of reservoir liners.
The proposed reclamation plan specifies the installation of two sealed reservoirs. These reservoirs
must meet the State Engineer's requirements for a lined pit in order for the reclamation of the
affected area to be deemed successful. No materials testing results and no enforceable designs,
plans, specifications, or quality assurance information is provided in the application. Thus, the
Division cannot regulate the installation of the liner [o assure i[ will meet standards. Under these
circumstances, adequate bond must be provided to line the entire pit.
• Dewatering costs for the 113.37 acre lakes with and average 30 foot water depth are 1108 million
gallons times $201.50/m.g. (1994 CDOT data) for a total direct cost of $223,262.00.
• Approximately 1,007,125 compacted cubic yards of liner material will be required to construct a
16,2501inear foot liner around [he perimeter of the lakes. This volume estimate assumes a 3:1
inslope for the wedge of liner material (see item 8 below), an average 33 foot pit depth, and
installation of a ]0 foot by 4 foot keyway. The estimated cost to rip the liner material from the pit
floor is $149,759.00 (see attached estimating sheet for ripper work).
• The ripped shale must be excavated and placed on the pit perimeters in thin lifts. The attached
estimating form for scraper work yields a cost for this task of $842,449.00 including the cost for
moisture conditioning, blending and grading of lifts, and compaction.
• Quality assurance testing and observation at $500.00 per day for 100 days yields a cost of
$50,000.00 for the project.
The total cost to reline the pits is $1,265,470.00 for 16,250 linear feet of liner. This amount should
be substituted for the Applicant's proposed lining costs in the Exhibit L cost estimate.
2. In order to reduce the amount of bond required to assure that sealed reservoirs will be constructed,
[he Applicant may provide design drawings and specifications for the installation of the pit liner
along with a quality assurance/quality control plan. These documents would be binding under the
terms of [he permit, and the Division would require a statement [hat these plans and drawings, once