2011-06-21_PERMIT FILE - M2010049 ‎(2)‎

• Permit No: M2010049
• IBM Index Class Name: PERMIT FILE
• Doc Date: 6/21/2011
• Doc Name: Adequacy Review- 07
• From: DRMS
• To: Varra Companies, Inc.
• Email Name: MAC
• Media Type: D
• Archive: No

DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
MEMORANDUM
To: Michael Cunningham, Environmental Protection Specialist
From: Tim Cazier, P.E., Environmental Protection Specialist
Date: June 17, 2011
STATE OF COLORADO
Re: Slope Stability Analyses Review of CGRS Responses to June 8, 2001 Review
for Western Sugar Reclamation Land Development Project, Permit No. M-
2010 -049
John W. Hickenlooper
Govemor
Mike King
Executive Director
Loretta Pineda
Director
The Division of Reclamation, Mining and Safety engineering staff (DRMS) have reviewed the
June 11, 2011 response letter to DRMS's June 8, 2011 Slope Stability Review for the Varra
Gravel Operation — Great Western Sugar, Greeley Colorado.
This follow -up review consisted of comparing the subject responses and the application content
with specific requirements of Rule 6.5 of the Minerals Rules and Regulations of the Colorado
Mined Land Reclamation Board for the Extraction of Construction Materials. The following
DRMS comments are presented in order of the "Item" numbers in the subject response letter:
Item 1 — Please provide further clarification as to whether any mining anywhere within the
permit boundary is proposed below a depth of 45 feet. Your response should also consider the
applicant's reclamation plan which proposes pushing up material from the bottom of the pit to
construct 3H:1V slopes. If the pit is mined to 45 feet, and no deeper, where is the material
coming from to push up the slope for reclamation?
Item 2(a) — The response provided is adequate.
Item 2(b) — The response stated "The values used were either reported by Terracon or in the
absence of measured values we used table values provided by your agency." There appear to be
some discrepancies between this statement and what was used in the STABL for Windows
model as shown in your "Soils Properties" screen capture in Attachment A of the response letter.
The attached Table 1 provides a summary of the various parameters used in the model; reported
by Terracon; and those recommended by DRMS. Please update the analyses with unit weight,
cohesion, and friction angle values for each of the five soil layers recommended by DRMS in the
attached Table 1, or provide some rationale as to why other values should be used, specifically
Office of Office of
Mined Land Reclamation
COLORADO
D I V I S I O N O F
RECLAMATION
MINING
— &—
SAFETY
Denver • Grand Junction • Durango Active and Inactive Mines