REV92207

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 9/1/1994
• Doc Name: SAN LUIS PROJECT PN M-88-112 TR-018 GEOCHEMICAL CONCERNS REGARDING WEST PIT BACKFILL PROPOSAL
• From: DMG
• To: JIM DILLIE
• Type & Sequence: TR18
• Media Type: D
• Archive: No

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999 i
STATE OF
DIVISION OF MINERALS AND GEOLOGY
Depanmenl o! NaNral Resources
1313 Sherman 51., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX:[phone]
DATE: September 1, 1994
TO: Jim Dillie
FROM: Bill York-Feirn
RE: San Luis Project, Permit No. M-88-112 - Revi 3.on No
018 - Geochemical Concerns Regarding the W~st Pit
Backfill Proposal
II~~~
DEPARTMENT OF
NATURAL
RESOURCE
Ray Romer
Governor
lames S. Lochhead
Executive Director
Michael B. Long
Divvy ~n Dueaor
The following are some comments and concerns that I ha a regarding
the geochemical characterization of the waste rock to b backfilled
in the West Pit at the San Luis Mine. These cowmen s are based
upon review of the May 9, 1994 SRK document submitted s TR-018 to
the permit, the August 24, 1994 fax concerning t e Geologic
Evaluation of the Backfill Material, discussions with y u on August
29, 1994 and a discussion with Alana Scott, Technical
Superintendent with BMRI on August 31, 1994.
General Comments
The geochemical data provided to date needs to be suppl mented with
additional data in four basic areas: (1) Proof that th 10 samples
collected for additional testing are actually represent tive of the
volume of material to be used for backfill, (2) Doc entation of
the minimum and maximum water table elevations to be ex ected after
completion of backfilling and equilibration, (3) Adequate
mineralogical and Petrographic analyses of the l0 additional
samples are provided and (4) A sufficient number of samples are
tested in humidity cells which mimick the long term exp~sure of the
material to air and meteoric or ground water.
Comment 1
The operator needs to provide a series of crossectio~s or level
plan maps which define, in three dimensions, the volume of material
to be used for backfilling the west pit. Geology, sulf de content,
major structures, drill hole locations which penetrate he backfill
material and location of the newly submitted geochemi al samples
should be included. This information will help veri y that the
samples submitted are representative of the backfi 1 material
containing sulfides.
Comment 2
A detailed mineralogical and petrological description of the l0