2007-05-15_GENERAL DOCUMENTS - M1980244

• Permit No: M1980244
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Date: 5/15/2007
• Doc Name: Proposed Uncertified Liner Isolation Barrier- AM#8
• From: Golder Associates Inc.
• To: CC&V
• Permit Index Doc Type: Gen. Correspondence
• Email Name: BMK
• Media Type: D
• Archive: No

Golder Associates Inc.
44 Union Boulevard, Suite 300
Lakewood, CO USA 80228
Telephone: [phone]
Fax: [phone]
www.golder.com
May 15, 2007
RECEIVED
14181, MAY 15 1007
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Our Ref: 073-2140
Cripple Creek & Victor Gold Mining Company
P.O. Box 191
Victor, CO 80860
Attention: Mr. Kevin Riley Process Operations Manager
RE: PROPOSED UNCERTIFIED LINER ISOLATION BARRIER, LOCATED NEAR
THE EXISTING LOAD OUT BIN, CRIPPLE CREEK AND VICTOR GOLD MINING
COMPANY, VICTOR, COLORADO
Dear Kevin:
Golder Associates, Inc. (Golder) has prepared this letter for the AngloGold Ashanti (Colorado)
Corporations' Cripple Creek and Victor Gold Mining Co. (CC&V) to present the engineering design
for the construction of a geomembrane liner barrier and for ore placement upslope of the existing
Phase IV load out bin (LOB) uncertified liner area.
Background
The thickness of drain cover fill (DCF) required to protect the integrity of the primary LLDPE
geomembrane liner is a function of the maximum stress level anticipated. In the immediate vicinity
of the LOB, Golder's Phase IV design provided for a minimum DCF thickness of 10 feet as a result
of ore haulage being conducted with 240-ton haul trucks. When CC&V commenced haulage with
300-ton haul trucks, the minimum required thickness of DCF increased from 10 feet to 20 feet. The
DCF in the areas adjacent to the LOB, where truck haulage from 300-ton haul trucks has occurred, no
longer meets the minimum thickness requirement for the maximum equipment load at the liner
interface (8.7 psi per the design criteria). As such, the primary LLDPE in this area is now designated
as uncertified liner. Leach solution has not been allowed to come into contact with the uncertified
area due to the potential of damage to the primary LLDPE geomembrane liner from haul traffic.
The area of uncertified liner is relatively small, covering approximately 56,240 square feet. However,
the presence of the uncertified liner currently precludes placement of ore over a much larger area of
the leach pad located up-gradient from the LOB.
The LOB is located on the southeast corner of the Phase IVc heap leach pad. Moving the LOB to a
new off-pad location and then reconstructing the uncertified liner is the only technically feasible way
to regain all of the ore capacity lost due as a result of the location of the uncertified liner. CC&V has
recently evaluated this option, and has decided it is not feasible to move the LOB until later in the life
of the project. Constructing a liner barrier will allow ore to be placed over a significant portion of the
currently unusable area upgradient of the uncertified liner until such time as relocation of the LOB
occurs.
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