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<br />Memo to Berhan Keffelew <br />CRESSON Leak Collection Audit <br />page 6 <br /> <br />One viable alternative to verifying the source of leak <br />collection system effluent is to compare the chemical <br />constituency of the fluids within the saturated pool and the <br />leak collection sump. As the Division has learned in the <br />Battle Mountain situation this involves analysis and <br />comparison of a full suite of chemical constituents, not just <br />Cyanide species. If the leak collection fluids emanate from <br />the saturated pool, the chemical constituency ("signature") of <br />the two fluids should be identical. If CC&VG's contention of <br />meteoric fluid entrained within the leak collection layer <br />during construction is valid, which the Division finds <br />plausible, the leak collection fluids would be initially <br />diluted by these meteoric waters. As the initial fluids are <br />pumped from the collection sump the dilution effect should <br />progressively decrease until equivalence is reached. If <br />equivalence is demonstrated CC&VG will have verified the <br />contention that leak collection system effluent is emanating <br />from the processing fluid. If equivalence is not reached <br />fairly rapidly, CC&VG should conduct a mass balance analysis <br />to determine the probable quantity and chemical constituency <br />of the diluting fluids. <br />Consequences of the leak collection system audit <br />If CC&VG corrects the existing leak collection fluid production <br />rate metering deficiencies, determines the actual rate of leak <br />collection system fluid production, verifies that the actual <br />leakage rate falls below the projected acceptable maximum leakage <br />for the saturated pool area and average hydraulic head, and <br />verifies that the chemical constituency of the fluids is <br />equivalent, the Division will consider the audit acceptable and <br />allow the placement of ore above the saturated pool processing <br />fluid high stand elevation. If CC&VG determines that the actual <br />leakage rate exceeds the maximum acceptable projected rate or that <br />fluids are entering from other sources CC&VG will need to propose <br />and implement appropriate remedial activities prior to proceeding <br />with the placement of additional ore. <br />attachment: <br />cc: Carl Mount <br />Bruce Humphries <br />Mike Long <br />Al Sorenson <br />Doc: M:\MIN\JAP\CRESSON\LEAKCOLL.AUD <br />JP/JP <br />