HYDRO30202

• Permit No: M1980244
• IBM Index Class Name: Hydrology
• Doc Date: 11/28/1994
• Doc Name: OFF SITE OF DETOXIFED LEACH PAD MATERIALS FROM CRIPPLE CREEK AND VICTOR GOLD MINE AS ROADBASE TELLER
• From: COLO DEPT OF PUBLIC HEALTH AND ENVIRONMENT
• To: DNR
• Media Type: D
• Archive: No

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STATE OF COLORADO
Roy Romer, Gwemor
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Patricia A No
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RECEIVED flealr6
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November 23, 199a NOV 2 8 1994
Mr. Berber Keffelew Division or Minerals & Geology
Environmental Protection Spxialist
Colorado Department of Natural Resources
Division of Minerals and Geology
1313 Sherman Street, Room 215
Denver, CO 801A3
Re: Off-Site Use of Detoxified Leach Pad Materials from Cripple Creek and Victor Gold Mine as Roadbase
Teller County
Dear Mr. Keffelew;
This letter is in response to your communication of November 4, 1994, in which you requested an assessment of the
water-quality impacts that might result from the use of detoxified heap leach materials as roadbase by the City of
Victor.
Any water quality impacts that might arise from the use of this material would likely be limited to those that are
caused by rain or snowmelt coming in contact with the material, and then either flowing to surface waters or
groundwater.
With respect to surface runoff, it is our understanding that the detoxified materials will be covered with some other
gravels or soils, which would minimize the potential for direct surface runoff of water that has come into contact
wiW the detoxified material. However, it is still possible for water that has infiltrated past the top layers of gravel
on the roads to come in contact with the heap leach material and then resurface as runoff. The meteoric water
mobility test results that you supplied show that there is the potential for concentrations of manganese, nitrate and
sulfate in water flowing over or through the leach pad material to exceed surface water stream standards, and it is
not known if dilution provided by water flowing in the receiving streams would prevent instream concentrations
from exceeding standards.
Therefore, should the detoxified material be used for base course, best management practices for the control of
stormwater would need to be implemented in order to prevent such runoff from directly entering surface streams.
Also, prior to any final approval, it should be verified that the acid genereting potential of the material is low
enough to prevent any increase in metals mobility over time.
With respect to the potential for impacts to groundwater, the Division's Crroundwater Unit bas indicated that they
would need to see some additioml types of enalyses,.such as TCLP or acid generation potential, in order to perform
an adequate evaluation. Also, and perhaps more importantly, it needs to be determined whether or not the
Department's Solid Waste Management Section would have the regulatory authority to control the placement of the
detoxified materials, and what types of analyses they would want to review.