1992-05-29_REVISION - M1988112 (3)

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' Collection of Surface and Ground Water Quality Data, Smt Luis Gold Project, Costilla Counry, i Colorado", dated April 1992 (John C. Halepaska and Associates, Inc., April 1992). ~' I, PROPOSED ADDITIONAL GROUND WATER MONITORING WELLS ' Baseline water quality data were obtained from select surface water and ground water monitoring ~ points for approximately three years prior to initiation of the mining process. Since mining has ', been initiated, water quality data from the surface water and ground water stations has continued to be collected and, to date, has not indicated degradation to either the surface water or the ground water in the vicinity of this project. This includes ground water quality data obtained from the monitoring wells downgradient of the tailings facility and collection pond after the CMLRB issued its Notice of Probable Violation due to higher-than-expected cyanide concentrations in the tailings pond. ' However, the CMLRD has expressed concerns related to the direction of ground water flow ' beneath the tailings facility and collection pond; namely, that the location of one monitoring point below the collection pond cannot adequately serve to develop a local ground water gradient in this vicinity, even though regional ground water data indicate a gradient from east to west towards the valley fill aquifer. Therefore, additional monitoring wells in the vicinity of the tailings facility and collection pond are necessary to develop the site-specific ground water Flow magnitude and direction. Based on this concern of the CMLRD, Battle Mountain is proposing additional monitoring well ' locations to evaluate the magnitude and direction of the local ground water flow and to evaluate if these ground water monitoring sites are adequate to create a hydraulic barrier downgradient ' of the tailings facility and collection pond, thus providing a means to rernediate any potential ' contamination to the local aquifer. ' 2