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-• , - . <br /> <br />additional samples must be provided to correlate wit the other <br />geochemical data. What are the sulfide mineral ? In what <br />proportions? What are the acid neutralizing mineralsipresent? <br />What trace elements exist in quantities that could possibly leach <br />under acid conditions into ground water? <br />Comment 3 <br />The two 1988 humidity cell sample results are inadequa a to fully <br />characterize the backfill material. The results sho weak acid <br />generating to weak acid neutralizing potential. In ad ition, the <br />trend seems to be slowly drifting to slightly more aci generating <br />conditions after 8 weeks. The tests must be run for uch longer <br />than 8 weeks. The Division would suggest on the order of at least <br />20 weeks. The 1988 humidity cell effluent was not a~alyzed for <br />metals, which is absolutely essential. The operato needs to <br />analyze the effluent from the new samples for all metal of concern <br />with respect to ground water quality standards. <br />Comment 4 <br />Ideally, it would be best to backfill <br />material back into the West Pit below <br />saturated zone of ground water. Is it <br />operator to reorganize the mining and <br />accomplish this? <br />all excava ed. pyritic <br />the upper le el of the <br />at all possi le for the <br />backfilling equence to <br />cc: Carl Mount, DMG <br />