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C~ <br /> <br />6attl2 ;lountain ~o;c <br />NOPV Abatement Requirements <br />page 3 <br />(6) Cyanide Detection, Interception, Containment and Remedial Treatment: <br />BMG originally proposed the construction of a heap leach at the San Luis <br />mine. In 1988, BMG amended its permit application to delete the heap <br />leach and implement a contained vat processing system. This amended <br />process was designed to yield detoxified tailings for disposal within the <br />tailings area. BMG replaced the originally proposed heap leac double <br />liner system with leak detection with a composite liner system without <br />leak detection. This amendment was approved by the Division r lying upon <br />BMG's representation that tailings Cyanide levels would not ex eed 3.8 <br />ppm WAD Cyanide and 4.4 ppm total Cyanide. <br />In the absence of a leak detection system, migrating leakage f'om the <br />tailings disposal ponds would only be detected by the five gro~ind water <br />monitoring wells (M-5, M-6, M-7, M-8 and M-9) located in the viicinity of <br />the tailings area. Since the inception of the approved monitoring <br />program, only monitoring well M-9 has intercepted ground water' The <br />analytical results from samples collected from well M-9 have n~t detected <br />any Cyanide occurrence. <br />The Division directs BMG to reevaluate its approved program fo ground <br />water monitoring, sampling and analysis for the tailings dispo al area. <br />At a minimum the Division believes that an expanded monitoring program, <br />including additional ground water monitoring wells, should be mpiemented <br />to ensure continuous penetration of the ground water table. F rther, the <br />Division believes that all tailings area monitoring facilities should be <br />sampled monthly and the analytical results reported expedition ly to the <br />Division. This evaluation report shall be submitted to the Di ision as a <br />technical revision prior to May 29, 1992. <br />further, BMG shall develop and submit a tailings effluent leak ge <br />interception, containment and treatment plan, to be implemente in the <br />event of contaminant migration from the tailings area. This c ntingency <br />response plan should specify methods to remedy contamination o ground <br />water, surface water and soil. This plan shall be submitted tc} the <br />Division as a technical revision prior to June 15, 1992. <br />Status: Satisfied - BMG has committed to development of remedial plan <br />(7) Modification of Ore Processing Methodology: <br />in letter of April 16, 1992. <br />- The requirements for monitoring plan modi ication <br />were only advanced by the Division on April 21, 1992. <br />- BMG verbally committed to modify the moni oring plan <br />on April 22, 1992. <br />BMG's preliminary suspicions of altered met=liic ore content, and the <br />coincidental failure of the designed processing cyanide raco w ~~ circuit, <br />