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Bulldog Mine Tal(ings Ponrls Evaluation <br />Associates summary report did not provide sufficient information to conclude that the tailings do <br />• not present a potential impact to ground water. The DMG agreed with Homestake that the <br />placement of wells in fractured flow system beneath the tailings would be unpredictable and <br />unreliable and that the chazacterization of the tailings was an acceptable alternative. <br />In June 1996, the DMG agreed to a tailings chazacterization program to assess the characteristics <br />of the tailings and site conditions at the Lower Tailings Pond. Although the focus of the program <br />was the Lower Tailings Pond, Homestake decided to conduct a concurrent evaluation of the <br />Upper Tailings Pond as well. <br />1.2 Sequence of 1996 Activities <br />The objectives and scope of the initial tailings evaluation were documented in a Work Plan <br />submitted to Homestake on June 21, 1996, and subsequently to the DMG for concurrence. Based <br />on the results of this initial evaluation, a Supplemental Work Plan was submitted to Homestake <br />on September 9, 1996. The two work plans aze included in Appendices D and E of this report. <br />• Work performed under the original Work Plan included drilling, logging and sampling of tailings <br />in both the Lower and Upper Tailings Ponds, and geochemical and geotechnical testing on <br />selected tailings samples. Work performed under the Supplemental Work Plan included <br />measuring oxygen concentration profiles and oxygen flux rates in the tailings and sampling <br />natural soils and tailings pore water for metals attenuation testing. <br />1.3 Use of Evaluation Results <br />The results of the field and laboratory testing conducted under the two work plans were used to <br />evaluate the following conditions. <br />The moisture and density conditions of the tailings in the ponds were measured to <br />assess the potential for significant drainage of tailings pore water with continued <br />consolidation. <br />?. The leachability chazacteristics of the tailings were assessed using batch leaching <br />testing procedures to simulate the water quality of seepage from the tailings resulting <br />from precipitation. <br />• 3. The current and future acid generation potential of the tailings was measured. <br />Homesmke ,Mining Company Shcplmrd Ililler. Inc. <br />p:v-dr~u„ud.~.n~ 2 .~pnl N, 199i <br />