1996-10-28_HYDROLOGY - M1984049

• Permit No: M1984049
• IBM Index Class Name: Hydrology
• Doc Date: 10/28/1996
• Doc Name: WATER SAMPLE FROM MILL DRAIN POND HOWARDSVILLE MILL M-84-049
• From: DMG
• To: HARRY POSEY
• Media Type: D
• Archive: No

999
STATE OF COLORADO
DIVISION MINERALS AND GEOLOGY of
Department of Natural Resources
1313 Sherman St., Room 215 n
Denver,Colorado 80203 .✓
Phone:[phone] 4P
FAX:[phone]
8 PARTMENT OF
DATE: October 25, 1996 g/�' ATURAL
Q� RESOURCES
T0: Harry Posey 46, yRomer
ernor
James S.Lochhead
FROM: Wally Erickson Executive Director
Michael B.Long
RE: Water Sample from Mill Drain Pond, Howardsville Mill, M-84-049. Division Director
Please find attached, analysis from 10/4/96 water sample, taken from the monitor well
for the mill drain pond for the Howardsville Mill. Mill drain pond monitor well is located
between the upper and lower liners of the pond. Upper and lower pond liners were
supposed to be separated by 1 ' layer of sand. After reviewing the attached analysis, I
suspected that tailings may have been substituted for inert material between the liners.
During our phone conversation on 10/25/96, you suggested that results of analysis may
also indicate leakage of the upper liner and that cyanide has been utilized at the
Howardsville Mill. You also stated a concern regarding hydrostatic pressure on the lower
liner, compounded by possible low permeability of the sand layer. Low permeability of
the sand layer was assumed by the long recharge time (1 week) for the monitor well
following well evacuation. Your recommendations included sampling and analysis of the
sand layer material to determine soil classification and chemical composition of the
material, and that I provide information on the liner material and sand layer to Allen
Sorenson.
The purpose of the mill drain pond is to contain fluids from mill building wash down and
to contain spills from the mill building. Cyanide recovery circuits are permitted in the
leach plant building, but not in the mill building. Leach plant building was designed as a
self contained structure and does not discharge to the mill building or mill drain pond.
Subsequent to our phone conversation on 10/25/96, 1 located analysis of water sample
taken from the mill drain pond on 10/14/92. The enclosed 1992 sample analysis was
apparently run on water sample from the pond, not from the monitor well.
Please review the enclosed analysis and provide recommendations for improvements
necessary to result in ensuring adequate containment of pond contents.
cc: Bruce Humphries
Jim Pendleton
Allen Sorenson