GENERAL47060

• Permit No: M1980244
• IBM Index Class Name: General Documents
• Doc Date: 10/17/1994
• Doc Name: CRESSON PROJECT PN M-80-244 PROVISION OF ADDITIONAL LARGE SCALE INTERFACE SHEAR TESTS RESULTS INCORP
• From: CRIPPLE CREEK & VICTOR GOLD MINING CO
• To: DMG
• Media Type: D
• Archive: No

Golder Associates Inc.
200 Union Boulevard. Suife 500
Lakewood, CO USA 80228
Telephone [phone]
Fax [phone]
October 10, 1994
Pikes Peak Mining Company
2755 State Highway 67
Victor, Colorado 80860
Attention: Mr. John Hardawav
ocr i > >ss4
Division o. Minerals & Geology
RE: CRESSON HEAP LEACH PAD -INTERFACE SHEAR TEST RESULTS USING VARYING
PERCENTAGES OF CARLTON AND GOLDSTAR TAILINGS
Dear Mr. Hardaway:
This letter transmits the results of additional large-scale interface shear testing that was performed
at the request of the Mined Land Reclamation Division (MLRDI. The testing was performed to
quantify the effect of the Carlton mill tailings and Goldstar tailings that have been sparingly placed
on the surface of the prepared Ironclad tailings (soil liner) to provide a smoother interface prior to
geomembrane liner placement.
The large-scale interface shear testing was performed for Golder Associates Inc. (Golder) in
Atlanta, Georgia by GeoSyntec Consultants IGeoSyntecl. The materials used in the interface shear
tests were obtained directly from the site and shipped to GeoSyntec. The materials were: 11 2-5
gallon buckets of liner cover fill obtained from Pad No. 2; 2) 2-5 gallon buckets of soil liner fill
obtained from the fill area; 3) 1-5 gallon bucket of Carlton mill tailings obtained from a small
temporary stockpile within the footprint of the Phase 1 pad; 41 1-5 gallon bucket of Goldstar
tailings obtained from a small temporary stockpile within the footprint of the Phase 1 pad; and 51
apiece of 80-mil VLDPE with approximate dimensions of 4 foot by 8 foot salvaged from a piece
of scrap geomembrane trimmed on the leach pad.
The testing configuration was assembled by compacting the soil liner fill to 95 percent of
maximum dry density (ASTM D698) at optimum moisture content and covering the prepared
surface of the soil liner fill with varying percentages (30 and 60) of Carlton and Goldstar tailings.
The surface was wetted prior to placement of the 80-mil VLDPE. The VLDPE was covered with
the liner cover fill from Pad No. 2 and wetted. The configuration was immediately sheared at 0.04
inches per minute.
Results obtained from the large-scale testing are presented in the following table:
Conligurasion Peak ~ Int. Fncfion 1°1 Peak - CoM1esion Ipsfl Revtlual Internal Fricsmn 1°1 Residual - CoM1eslon lpsfl
Carson Tails 30% 23 1010 23 1010
Carlson Tails 60% Z4 1045 34 1045
Goldssar Taas - 30% R4 )q0 24 ]q0
Goldssar Tans ~ 60% Pending Pending Pentlmg Pendng
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