HYDRO28407

• Permit No: M1980244
• IBM Index Class Name: Hydrology
• Doc Date: 5/19/1994
• Doc Name: CRESSON GEOCHEMISTRY MILESTONES RE-REVISED
• From: MDG
• To: BERHAN KEFFELEW
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
De parlmenl of Natural Resources
1313 Sherman St., Raom 215
Denver, Colorado 80207
Phone: [phone]
FAX: [phone]
DATE: May 19, 1994
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DEPARTMENT OF
NATURAL
RESOURCES
Roy Ramer
T0: Berhan Keffelew c„~yer„~r
Ken Salazar
FRAM: Harry POSey EaecW ire Dura ur
Michael B Lonl;
RE: Cresson Geochemistry ilestones: Re-Revised oiv ision Duec^)r
Following are geochemical milestones that should be reached before CC6V proceed to
stages of their operation that may depend on successful geochemical tests. These
reflect a review by Bruce Humphries.
1. Clay liner testing.
The permit amendment indicates that the compacted "clay" liner will be
constructed of the vat leach tailings. Currently these tailings contain
process levels of cyanide and may have leachable metals and a potential for
acid generation. CC6V have committed to rinsing the tailings prior to
placement.
Prior to placement of the clay liner beneath the pad, test results
demonstrating cyanide detoxification must be approved by the Office prior to
material placement.
Prior to commencement of the rinsing operation, CCTV must submit a plan for
dealing with the rinse solutions.
As indicated in the permit amendment, representative liner samples must be
analyzed for WAD and Total Cyanide. Analyses of each unit as specified in the
Amendment #6 stipulations (commitments) must be completed and an interpretive
report submitted to the Office for approval prior to placement of the material.
Accompanying the analyses, CC&V must demonstrate that the samples are
representative of the liner material.
Metals leachability tests must be conducted on representative samples as
specified in Amendment #6 stipulations (commitments). Test results and an
interpretative report must be submitted to the Office for approval prior to
placement of liner materials.
2. Geochemical analysis of the pit floor.
Amendment #6 commits to analyzing the pit floor once the operation exposes
sulfide minerals. The results are to be used to indicate what measures must
be taken to prevent the generation and/or release of metals and acid to the
sub-pit area including the Carlton tunnel discharge.
Prior to the commencement of mining in the sulfide bearing areas, geochemical
analyses of the pit floor must be completed and an interpretation report
submitted to the Division for approval prior to mining.