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<br />established to protect the most sensitive species and also that standards have abuilt-in <br />factor of safety. Simple exceedances of water standards do not necessarily imply <br />imminent risk; ephemeral exceedances imply low risk if any, and some exceedances <br />may provide no risk to some receptors. In the current case, considering the <br />contaminants of concerns and their pathways, there is no imminent risk to human <br />health, no risk to aquatic life, and uncertain or dubious risks to agricultural uses. <br />The Reviewer employs the Operator's statement "that elevated manganese levels are <br />due to "natural" manganese loadings" as if all of the manganese was considered to be <br />natural. This was neither stated nor implied in TR-2b. The Operator noted areas <br />where naturally elevated levels of manganese have occurred in the past, and <br />incorporated those measurements into the overall study. Based on the hydrologic and <br />~eochemical evidence, the Division concurs with the operator that not all of the <br />manganese at station RS-2 is from the West Pit; some is from other sources. <br />SUPPLEMENTAL TR-26 REVIEW COMMENTS <br />1. Most of the drainage above Waste Rock C, which lies generally between and uphill of <br />the East and West Pits, is directed into the Waste Rock C facility, as designed. <br />Diversion structures, which are inscribed into the Waste Rock C facility, divert and <br />carry overland flow which falls on the waste rock. There are no diversion structures <br />upgradient of Waste Rock C. <br />Whether or to what extent this waste rock is a source of contaminants is not known. <br />BMRI has indicated in conversations that they may propose to divert this drainage in <br />some to prevent it from flowing into the Waste Rock C facility. It seems that it may <br />be feasible to direct all or part of the drainage either into the Pink Gneiss Pit or more <br />directly into the backfill of the West Pit. By so doing, this may enhance the rate of <br />rinsing of the west pit and/or pink gneiss pit waste rock. Please comment. <br />cc: Jim Stevens <br />Jim Pendleton <br />c:\hhp\geochem reviews\BMG TR-26 Review <br />