1995-06-14_HYDROLOGY - M1977378

• Permit No: M1977378
• IBM Index Class Name: HYDROLOGY
• Doc Date: 6/14/1995
• Doc Name: Control Chart for Measurement of Animas River Water Quality.
• From: Sunnyside Gold Corp
• To: CDPHE-WQCD
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

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WATER QUALITY ET' .JATIONS AT STATION A72 ON THE ANI,....S RIVER USING sss
CONTROL CHARTS
TECHNICAL MEMORANDUM �' ,V
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DATE: 9 June, 1995
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TO: William Goodhard (Sunnyside Gold Corporation)
FROM: Mark J. Logsdon (Geochimica)
RE: CONTROL CHARTING OF WATER QUALITY BASED ON
CLASSES OF FLOW AT STATION A72, ANIMAS RIVER
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BACKGROUND
Colorado Department of Public Health and Environment, through its Water Quality
Control Division (WQCD), has undertaken studies to evaluate the ambient water
quality in the upper Animas River. It is the position of the WQCD that (a) ambient
water quality should not be degraded and (b) it should be a State goal that water quality
in the Animas River improve over time. Both weathering of natural mineralization and
mining activities, both historical and current, are sources of metals and other solutes to
the Animas River.
Sunnyside Gold Corporation (SGC) has ceased operations at the Sunnyside Mine, San
Juan County, Colorado, located on streams that are tributary to the Animas River
above Silverton, Colorado. As part of mine closure, SGC intends to bulkhead the
workings and allow the mine to re-saturate; when the bulkheading is complete, there no
longer would be discharge from the mine workings. SGC and its advisors believe that
re-saturating the mine workings and forcing water to flow through the natural ground
will limit acid generation and leaching of metals and restore the ground-water regime in
the vicinity of the mine to an approximation of its pre-mining condition.
In addition to the bulkheading of the Sunnyside Mine, SGC plans to undertake a variety
of surface reclamation activities in the headwaters of the Animas drainage that are
intended to decrease loadings from historical mining activities to the Animas system.
For a period of time, SGC will continue to operate its water treatment plant, treating
water from Cement Creek above the current outfall of the American Tunnel and the
surface facilities of the Sunnyside Mine
SGC and WQCD have identified a location (called Station A72) on the Animas River
just downstream of Silverton, Colorado that appears to be a suitable location for long-
term monitoring of water quality and flow conditions in the upper basin. Both parties
agree that it is appropriate to use flow and water-quality data from Station A72 to
evaluate how conditions, including reclamation activities, across the entire drainage
basin above A72 affect the Animas River.
Geochimica, Inc. 1 ANIMAS RIVER19-Jun-95