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-1 <br />III IIIIIIIII IIII III <br />DIViS[ON OF MINERAL AND GEOLOGY <br />INTEROFFICE MEMO <br />Date: March 8, 2000 " <br />To: Bruce Humphries <br />From: Harry Pose <br />7~~. N0...we•. <br />Subject: l Reclamation and <br />Bulldog Mine, Homestake <br />Re: Allen Cox' 25 February letter to Mike Long regarding reclamation and potential <br />CERCLA actions at Bulldog: <br />As Mr. Cox' letter and the USFS letter attachments indicate, the USFS intends to use <br />CERCLA authority to address "a release or threat of release of hazardous substances <br />from Bulldog waste rock dumps in Windy Gulch." (The USFS information comes from <br />the Preliminary Assessment (PA) conducted for EPA.) The extent to which DMG will <br />become involved in a potential CERCLA action at this active site is at issue. <br />Water quality data were reviewed by DMG a couple of years ago. At that time, it <br />appeazed possible that the Windy Gulch zinc load might be from natural sources. <br />However, as this was not proven, Homestake began a study under which they installed a <br />monitor well between the 9360 and 9700 levels, injected dye tracer behind the 9360 plug, <br />and instituted surface and alluvial water sampling. This study is partially complete. <br />Windy Gulch flows subsurface through alluvium above the 9700 level. Whether Windy <br />Gulch persistently comes in contact with the 97001eve1 waste rock is not known. The <br />surface and alluvial water monitoring should answer this question. <br />Windy Gulch surface water does not flow through the 9700 level waste rock; rather, the <br />surface water is piped around the waste rock, through the alluvium. Piezometer readings <br />at the 9360 level and the dye tracer indicate that water behind the 9630 plug probably <br />does NOT enter the 93601evel waste. If it does, it contacts the waste only at the <br />outermost edge, near the seep line which is near the center of the Gulch. <br />Homestake has not yet delivered their water quality assessment for Windy Gulch so we <br />do not know whether the 9360 or 9700 level waste rock dumps are contaminant sources <br />or not. Certainly, they do release contaminants to stormwater and snowmelt, but <br />stormwater I believe would be exempt from numeric water quality standards. <br />