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• <br />Memo to Harry Posev -3- Januarv 24. 1997 <br />(below the 9360' portal) are natural and possibly mining impacted <br />ground water discharges to the stream, as well as non point source <br />runoff from altered or mineralized bedrock exposed in the gulch <br />walls. In addition, a potentially higher rock:water ratio in the <br />downgradient, talus-dominated stream could contribute higher. <br />concentrations of dissolved metals. Below the 9360' portal, Windy <br />Gulch parallels a segment of the Bulldog Mountain Fault for <br />approximately 1000 feet. The Bulldog Mountain Fault is known to be <br />mineralized. Windy Gulch also crosses over two or three other <br />faults before reaching sample station 16. Ground water seepage at <br />the surface traces of these faults, or dissolution of metals from <br />the mineralized faults where the stream passes over them, could <br />contribute significant metals loading to Windy Gulch. Also, <br />between the 9360' portal location and the confluence with Willow <br />Creek, windy Gulch passes through the elevation of the top of the <br />mine pool in the flooded underground workings of the Bulldog Mine. <br />The mine pool elevation was last measured in November of 1992 at <br />9176'. It is possible that mine pool water is moving through <br />fracture systems and discharging to Windy Gulch or other surface <br />streams in the area surrounding the mine. The Division of Minerals <br />and Geology determined in 1994 that this potential for <br />environmental impact needed to be investigated. This determination <br />was made under the Division's ground water authority at mine sites. <br />Homestake appealed the Division's determination to the Mined Land <br />Reclamation Board and a formal public hearing was held at which the <br />Board found in favor of Homestake. <br />Some potentially useful information for lower Windy Gulch was <br />developed prior to the Board's decision, and is provided here. <br />During July of 1994, Homestake commissioned a spring and seep <br />survey of Windy Gulch from the 9360' elevation down to the mouth of <br />Windy Gulch. At the time of the study, most of Windy Gulch was <br />dry. The only flowing reach was observed from about elevation <br />9080' to 8870'. Flows were estimated to be from about 5 to 15 gpm <br />over this reach of stream. A water quality sample was collected <br />from the flowing reach at approximate elevation of 8890'. The <br />following dissolved metals were detected in the sample at the <br />listed concentrations: <br />Zinc - 4.4 mg/L <br />Cadmium - 0.019 mg/L <br />Arsenic - 0.012 mgfL <br />This flow in Windy Gulch is an emergent ground water forced to the <br />surface at a bedrock exposure in the stream bed. The most likely <br />causes of the metals contamination of this water are (1) flow past <br />or through mineralized or altered rocks naturally present <br />upgradient from the ground water emergence, (2) that this water is <br />a surface expression of the Bulldog Mine pool, or (3) that this <br />water had picked up metals through contact with the Bulldog Mine <br />