2010-01-28_PERMIT FILE - M2009082

• Permit No: M2009082
• IBM Index Class Name: PERMIT FILE
• Doc Date: 1/28/2010
• Doc Name: Review of Stability Analysis Report
• From: DRMS-psh
• To: DRMS-jle
• Email Name: JLE
• 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]
DATE: January 28, 2010
TO: Jared Ebert
FROM: Peter Hays
RE: Review of Stability Analysis Report, Lafarge West, Inc., Parsons Mine,
File No. M-2009-082
COLORADO
D I V I S I ON OF
RECLAMATION
MINING
SAFETY
Bill Ritter, Jr.
Governor
Harris D. Sherman
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
The Division of Reclamation, Mining, and Safety (Division) engineering staff has reviewed the critical cross
sections for the above referenced permit application. Using Clover Technology's Galena v5.01 slope
stability software, the Division has conducted further analysis of the cross sections for the Parsons Mine.
Specific comments for each mining phase are provided below.
Phase 1A
1. The depth of overburden used for the stability analysis model (6 feet) does not match the depth (4
feet) indicated on Table 1: Parsons Mine Borings and MW-03 Borehole Log. Please explain the
discrepancy.
The applicant's analysis was duplicated for verification; no potential failure surfaces with lower safety
factors than the applicant's identified critical slip circle were located. The safety factor produced by
Galena is slightly higher than that produced by Slope/W; this is due to slight programming differences in
the software packages and is not significant. Therefore, the accuracy of the applicant's analysis is
confirmed (see attached).
Phase 1B
2. Please confirm the stability analysis model labeled "Phase 1B Boring:ET02-TP05" is actually the
Boring Log for ET02-BH01 within Phase 1B.
The applicant's analysis was duplicated for verification; no potential failure surfaces with lower safety
factors than the applicant's identified critical slip circle were located. The safety factor produced by
Galena is higher than that produced by Slope/W; this is due to slight programming differences in the
software packages and is not significant. Therefore, the accuracy of the applicant's analysis is confirmed
(see attached).
Office of office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines