1993-11-03_REVISION - M1988112 ‎(2)‎

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 11/3/1993
• Doc Name: FAX COVER
• From: DMG
• To: ANDRE DAUCHANE
• Type & Sequence: AM1
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
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1313 Sherman Sl., Room 215 A~
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Denver, CO 80207 .
Phone: [phone] 'lab'
FA%.(3031832-8106
Roy Romcr

November 2, 1993 Governor
nlichael 8. long
Division Director
Mr. Ken Kluksdahl, Operations Manager
Battle Mountain Resources, Inc.
P.O. Box 310
San Luis, CO 81152-0310
RE: Division Review Comments, BMRI - October 13, 1993, Construction
Status Report, San Luis Project Tailings Area, Phase II, Raise I,
File No. M-SS-112
Dear Mr. Kluksdahl:
On October 18, 1993 the Division received the above captioned report
which was prepared primarily to address issues raised by the Division
in a meeting held on October 8, 1993 and identified during previous
reviews of BMRI submittals and the September 30-October 1, 1993
Phase II inspection. Allen Sorenson of our office completed a
technical review of your report,
There are three construction activities of Phase II that the Division
has concerns about, the embankment raise fill, drainage blanket, and
compacted soil liner (liner sub-base). Mr. Sorenson's concerns are
shown below. Please review them and provide appropriate responses
paying particular attention to those portions that are underlined.
DISCUSSION
The Division believes that there are two components of any liner
system that are integral to containment, they are:
1. A composite liner system consisting of a low permea:oility soil
liner directly overlain by, and in intimate contact with, a
geomembrane.
A method by which the hydrostatic head on the composite liner can
be minimized.
One of the reasons that the Division did not require a more verifiable
head minimization system at the San Luis facility, such as geogrid
sandwiched between two geomembranes for leak collection and removal,
was BMRI's assurance that the tailing liquids, (the fluid intended to
be collected by the drainage blanket), would be low in cyanide. The
early failure of the AVR system to eliminate cyanide from the tailing
entering the impoundment, has created a situation where a considerable
volume of high cyanide fluids may be migrating through the tailing
pile.
It is now evident that the hydraulic conductivity of the drainage
blanket is lower than was anticipated by the design engineer. This