REV93948

• Permit No: M1980244
• IBM Index Class Name: Revision
• Doc Date: 8/23/2000
• From: WQCD
• To: DMG
• Type & Sequence: AM8
• Media Type: D
• Archive: No

STATF. OF COLORADO
Bill Owens, Governor
Jane E. Norton, Executive Director
Dedicated to protecting and improving the health and environment of the people of Colorado
4700 Cherry Creek Dr. 5.
Denver, Colorado 80246-t 530
Phone [phone]
iDD Line (307) 697 -7700
Located in Glendale, Colorado
h «p://www.cdphe.sra[e.co. us
Mazch 13, 2000
Laboratory and Radiation 6ervites Division
8100 Lowry BNd.
Denver CO 80230-6928
(7031 692-7090
Scott A. Lewis, Manager of Environmental Affairs
Cripple Creek & Victor Gold Mining Company
P.O. Box 191
Victor, Colorado 80860
RE: Reported Upset Conditions
Cripple Creek & Victor Gold Mining Company
CDPS Permit No.: CO-0043648
CDPS Permit No.: CO-0024562
Deaz Mr. Lewis:
Of'CO
Nc~
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~ la'!6 ~
Colorado Department
of Public Health
and Environment
We have reviewed the extensive additional information that Cripple Creek & Victor Gold Mining
Company (CC&V) has submitted, in response to the Division's letters dated August 23, 1999, regarding
potential upset conditions that occurred at the Cazlton Tunnel and Arequa Gulch. The Division has
reviewed this information and offers the following comments:
Carlton Tunnel
The information received included a characterization study of the upset condition at~ttte Cazlton Tunnel
performed by Shepherd Miller (SM). This study concludes that the heavy precipitation during April of
last year caused flushing of mineralized water into the tunnel that led to the high effluent concentrations
of potentially dissolved zinc in the dischazge. The Division of Minerals and Geology (DMG) evaluated
this situation and offered that hydraulic flushing of soluble minerals found in the rock drained by the
Cazlton Tunnel could have produced a flush of zinc in the overlying formation during excessive or
above normal precipitation events. We agree with Shepherd Miller's conclusion that heavy
precipitation caused a flushing condition in the native rock which, in turn, caused exceedances of the
zinc effluent limitations for Outfal1002A. Section 61.8(3)(j) of the Colorado Dischazge Permit
Regulations states that: "... a permittee who wishes to establish the affirmative defense of upset for a
violation of effluent limitations based upon water quality standazds shall demonstrate through
monitoring, modeling or other methods that the relevant standazds were achieved in the receiving
water." Since the potentially dissolved zinc permit limit at the Cazlton Tunnel is a water quality
standazds based limit, to demonstrate that an upset is applicable in this case, CC&V provided the
Division with information that demonstrates that there was no in-stream exceedance of the water quality
standard for zinc during the months of May and June of 1999. The Division has, therefore, determined
that the upset condition provisions of the regulations apply in this case. As such, the Division does not
intend to pursue a formal enforcement action for these exceedances of the effluent zinc limitations.