2010-10-07_REVISION - M1981068

• Permit No: M1981068
• IBM Index Class Name: REVISION
• Doc Date: 10/7/2010
• Doc Name: Preliminary adequacy review ‎(TR-03)‎
• From: DRMS
• To: Water Resources Consultants, LLC
• Type & Sequence: TR3
• Email Name: DMC
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
?f0/7/2010
Paul Currier
Water Resources Consultants, LLC
244 Hutton Avenue
Rifle, CC)
81650
OCR 12 2010
" sooty
COLORADO
D I V I S 10 N OF
RECLAMATION
MINING
SAFETY
Bill Ritter, Jr.
Governor
Mike King
Executive Director
Loretta E. Pifiecla
Director
RE: Loesch Pit, File No. M-1981-068, Technical Revision Preliminary Adequacy Review, Revision No. TR-3 `-
Dear Mr. Currier:
On October 5, 2010 the Division of Reclamation, Mining and Safety (DRMS) received the Technical Revision application
submitted to DRMS addressing the use of a liner on portions of the pit walls, at the above referenced site, that will allow
the operator to better manage groundwater seepage into the pit. Staff has conducted a preliminary review of the
material submitted and has several questions regarding this issue. First, how much of the pit wall has already been
lined? Also, where are the locations of the portions of the pit that are currently lined? DRMS may deem it necessary to
hold an additional bond amount adequate for repairing any potential slope failure that may be caused by the installation
of the liner. This is due to the fact that until water is allowed to pond in the pit, there will be some net hydrostatic
pressure on the outside of the liner.
DRMS staff has determined that the following changes to the current liner installation methods will improve long-term
stability of the reclaimed slopes in areas where a liner has been installed (Figure 1).
1. Key the top of the liner into the subsurface to a minimum depth of one foot. It will not be necessary to key in
the bottom of the liner, but continue the practice of lapping the liner three to five feet onto the bedrock floor.
2. Cover the upper portion of the liner with a minimum depth of three feet of overburden and/or topsoil material.
The uppermost eight inches of material must be topsoil.
3. Commit to final grading of slopes to a minimum steepness of 4H:1V in areas where a liner has been installed.
It will not be necessary to remove any liner that has already been installed, but these changes will be required on any
future installations. If you feel that these changes are unnecessary, please provide additional information showing such.
Office of
Mined Land Reclamation
Denver • Grand Junction - Durango Office of
Active and Inactive Mines