2013-07-30_REVISION - M1985112

• Permit No: M1985112
• IBM Index Class Name: REVISION
• Doc Date: 7/30/2013
• Doc Name: ADEQUACY REVIEW - SLOPE STABILITY ANALYSIS
• From: DRMS
• To: OPERATOR
• Type & Sequence: TR1
• Email Name: PSH
• Email Name: TAK
• 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- (303) 832 -8106
DATE: July 30, 2013
TO: Peter Hayes, DRMS
FROM: TC Wait, DRMS
SUBJECT: Loloff Pit (M -1985 -112)
Review of Slope Stability Report (7/2013 by J &T Consulting)
COLORADO
D I V I S ION OF
RECLAMATION
MINING
SAFETY
John W. Hickenlooper
Governor
Mike King
Executive Director
Loretta E. Pineda
Director
Per your request, I have reviewed the slope stability report for the Loloff Pit prepared by J &T
Consulting, dated July 2013. This stability report was prepared as part of the Techincal Revision
No. 1 Request. The comments below should be considered as part of the adequacy response for
DRMS.
• The TR -1 request included changing the mining method to dewater the existing pond to
mine under dry conditions at a 3:1 slope. It is my understanding that the final land use
will remain wildlife habitat and include a pond. In general, the stability report was well -
written and adequately addressed the slope stability for the pit during the proposed
mining activity described in the TR.
• Basalm Avenue runs along the eastern edge of the site. There are a number of
underground utility lines associated with this road alignment. The analysis should be
sure to include effects on and from these utilities, including the possibility of water being
introduced from a leaking sewer or water line.
• The water level used in the analysis is approximately 12 ft below the ground surface on
the unaffected ground. This may not accurately reflect seasonally high conditions, or
conditions after the mine is flooded with water.
• The analysis sections are depicting "dry" conditions that would be found during mining
while the site is being de- watered. The stability should also be analyzed in "wet"
conditions that would represent post- mining conditions for longfterm stability.
• The report includes good recommendations for monitoring of slope stability. However, it
may be prudent to modify the inspections outlined in recommendation #1 and #4 on page
5 to a weekly basis for the duration of mining, then for 6 months post- mining.
Office of
Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines