INSPEC25091

• Permit No: M1977215
• IBM Index Class Name: Inspection
• Doc Date: 1/5/1993
• Doc Name: HYDROLOGIC EVALUATION FOR BULLDOG MINE FN M 77-215
• From: DMG
• To: HOMESTALK MINING CO
• Media Type: D
• Archive: No

•
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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
131 3 Sherman St., Room 215
Denver, CO 80203
Phone: [phone]
FAX: [phone]
January 5, 1993
Mr. Luke J. Russell
Homestake Mining Company
650 California Street
San Francisco, CA 94108-2788
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Roy Romer
Governor
Michael8 Long
Division Director
Re: Hydrologic Evaluation for Bulldog Mine, File No. M-77-215
Dear Mr. Russell:
The Division has reviewed the materials you submitted in response
to our discussions subsequent to the August 13, 1993 inspection of
the Bulldog Mine. By and large, the submittal has adequately
addressed the Division's concerns, however, we believe that the
selection of an SCS Curve Number of 55 for the hydrologic analysis
requires further clarification.
Based on the limited soils and vegetation information contained
within the Division's Bulldog Mine Permit files, Curve Numbers from
74 to 86 would appear to be more appropriate for the contributing
sub-basins. These higher curve numbers would result in
considerably higher peak runoffs for the structures in question.
In order to assure that the tailing pond diversion ditches, and
Windy Gulch in the vicinity of the mine waste dump, are capable of
passing flows resulting from a 10-year, 24-hour storm, please
provide the Division with justification for the selection of a
Curve Number of 55. Such justification should be based upon the
hydrologic soil groups located within the sub-basins, land use and
condition of vegetation, including percentage of cover, and
antecedent moisture condition.
If you have any questions, please contact me.
Sincerely,
,. ~'
Allen C. Sorenson
Reclamation Specialist
cc: Berhan Keffelew, DMG
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