HYDRO20909

• Permit No: M1980244
• IBM Index Class Name: Hydrology
• Doc Date: 5/30/1995
• Doc Name: SUGGESTED CHANGES TO COMMITMENTS 29 30 31 AND 36
• From: DMG
• To: BRUCE HUMPHRIES
• Media Type: D
• Archive: No

• • iii iisiiiiiiiiii iii
999
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources
1313 Sherman 51 ,Room 215 lii~
Denver, Colorado 80203 II
Phone: [phone]
FA%: (3031 832-8106
DEPARTMENT OF
NATURAL
RESOURCES
Rov Romer
Governor
lames S Lochhead
DATE: May 30, 1995 e.e<~iwe ~irednr
Michael B. Long;
Drcision Dueanr
TO: Bruce Humphries
FROM: Berhan Keffelew
RE: Suggested Changes to Commitments 29, 30, 31, and 36
The following changes could make the above numbered commitments more enforceable
than the way they were written during the approval process for Amendments 5 and 6 for
Permit No. M-80-244.
(9)(29) If free or WAD cyanide is detected in the effluent from the Arequa Gulch
underdrain in concentrations that exceed baseline levely~yhich are
undetectable in the 24 inch perforated pipe and 4 inch spring water
collection pipe which carry the groundwater flow below the leach pad
facility and .03 mg/I WAD cyanide for the discharge from the solid 24 inch
in pipe which will carry surface water in any of the ground water
monitoring wells in Wilson and Arequa Gulcly~vhich are undetectable or
below detection limits in all but well CRMW-3A & B in Arequa Gulch,
which showed a .03 WAD cyanide, the Office will conclude that heap
leach containment has been lost.
If WAD cyanide contaminated effluent that exceed .5mg/ICters the leak
detection system trenches or if the rate of solution in sumps exc~d
one (1) GPD per acre for the entire watershed that will contribute flow to
each trench, the Office will conclude that heap leach containment has
been lost. The operator shall notify the Office with 24 hours in the event
of any of these occurrences. Further, the operator shall immediately cease
application of leaching solution to the heap leach and initiate detoxification
within one week. Detoxification shall continue until an acceptable remedy
has been approved by the OMLR and implemented by the permittee. All
fluid volumes collected from the leak detection sumps shall be inventoried
by sump weekly and reported to the OMLR in writing once a month.