PERMFILE106687

• Permit No: M2000016
• IBM Index Class Name: Permit File
• Doc Date: 4/20/2000
• Doc Name: ADEQUACY REVIEW 112 CONSTRUCTION MATERIALS APPLICATION RIVERBEND OPERATION MOBILE PREMIX CONCRETE IN
• From: DMG
• To: MOBILE PREMIX CONCRETE
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Departmem of Nawral Resources
1313 Sherman St.. Room 275
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]:-8106
DATE: April l2, 2000
TO: Gregg Squire
FROM: Allen Sorenson t"f ` 5
RE: Reservoir Liner and Mining Setbacks, Mobile Pre-Mix Concrete Inc.,
Riverbend Pit, File No. M-00-016
D I VISION O F
MINERALS
GEOLOGY
R E C L A M A T I O N
MsNSNG•SAFETY
BIII Owes
Governor
Greg E. wakher
Executive D~reaor
Michael B. Long
Drv~sion Director
The following application adequacy items are limited to the Division's review of the portions 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 azea to be deemed successful. No materials testing results and no enforceable designs,
plans, specifications, or quality asswance information is provided in the application. Thus, the
Division cannot regulate the installation of the liner to assure it 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 aze 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
16,2501ineaz foot liner around the 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 10 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,
the Applicant may provide design drawings and specificatians for the installation of the pit finer
along with a quality assurance/quality control plan. These documents would be binding under the
terms of the permit, and [he Division would require a statement that these plans and drawings, once