REP24453

• Permit No: M1977215
• IBM Index Class Name: Report
• Doc Date: 12/27/1995
• Doc Name: MEMO-DESCRIPTION OF - SUMMARY TABLE FOR TAILING LEACHATE STUDY - HOMESTAKE MINING CO BULLDOG MINE
• From: DMG
• To: FILE
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OE MINERALS AND GEOLOGY
Depanmenl of Nawral Resources
1313 Sherman Si.. Ruum 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
DATE: December 27, 1995
TO: File No. M-77-215
FROM: Allen Sorenson TT,~
II~~~
DEPARTMENT OF
NATURAL
RESOURCES
Roy ROnier
Governor
fames 5. Lochhead
E.ecmive DlfeClOr
Michael B. long
Division Director
RE: Description of "SUMMARY TABLE FOR TAILING LEACHATE STUDY",
Homestake Mining Company, Bulldog Mine, Permit No. M-77-215
Attached to this memorandum is a Summary Table for a tailing leachate
study conducted by the Division for both the upper and lower tailing
impoundments at the Bulldog Mine. Collection of the tailing samples used
in the study is described in the Division's inspection report dated
September 11, 1995. Methods used in generation and analysis of the
leachate are described in "CHEMAC ENVIRONMENTAL SERVICES - ANALYTICAL
REPORT, State of Colorado - Division of Minerals and Geology, Spent Ore
Study" dated November 14, 1995.
To conduct the leachate study on the Bulldog Mill tailing, Chemac
Environmental Services completed single contact batch leachability testing
on tailing samples from both the upper and lower tailing impoundments.
This testing consisted of combining measured quantities of tailing and
synthetic meteoric leaching solution in one-gallon jars. A 2:1 liquid to
solid ratio was utilized, with a 24 hour contact time, and continuous
mixing achieved using a bottle roll apparatus. At the conclusion of the
24 hour contact period, the liquid was separated using a filter press, and
was further filtered through a 0.45 µm membrane: This leachate was then
appropriately preserved and shipped to Auburn Analytical, Inc. for
analysis for selected constituents. Selected results from this analysis
are tabulated in the attached table under the column heading °Single
Upper" for the single contact batch leachability testing of tailing from
the upper tailing pond, and under the column heading "Single Lower" for
the single contact batch leachability testing of tailing from the lower
tailing pond.
The leachable characteristics of the tailing sample from the lower tailing
pond were examined in more detail by conducting a sequential batch test.
One path of the sequential batch test was conducted by using the filtrate
from a single contact batch leachability test described above to leach a
fresh tailing sample, then preparing and analyzing this "double contact"
leachate in the same way as the leachate from the single contact tests.
Selected results of the analysis of the "double contact" leachate are