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M N <br />A <br />John Hardaway <br />-2- <br />April 13, 1995 <br />2. Certain action must be taken by the operator to. inhibit the generation of <br />acid and toxic materials (dissolved metals) to the extent that release of those <br />materials would violate applicable water quality standards for the receiving <br />streams. <br />The Division maintains again that leachability data must be evaluated relative to some <br />reasonable measure. CC & VG chose to evaluate the data in terms of "Ambient water <br />quality" at Station AG-1 in Arequa Gulch. We have determined that this is not an <br />appropriate measure. The most reasonable one, we believe, is the proposed water quality <br />standards for AG 1.5 and Squaw Gulch, namely, the same as Segment 21 of the Arkansas <br />River. We recognize the fact that the Division has no jurisdiction over surface water <br />quality standards. <br />The results of the leaching studies confirm that the leachates exceed water quality <br />standards, according to the following: <br />1. Many samples produced leachates with pH below 6.5, which is the regulated <br />lower limit for surface water. <br />2. Many samples produced leachates that had metal concentrations that were <br />higher than would be allowed by surface water quality standards as explained <br />previously. <br />3. The detection limits of several metals were not low enough to detect metals <br />at the levels that would be regulated under the proposed scheme for the <br />CDPS discharge permit. <br />Conclusions <br />It is the Division's conclusion that "It is incumbent upon CC fr VG to prepare for the <br />Division a reclamation plan to prevent the generation and release of acid and toxic material. <br />Capping of the heap and waste rock piles which include Iron Clad and Globehill pits, would be <br />acceptable provided the caps are su~ciently impermeable to slow the generation and release of <br />acid and toxic material to meet water quality compliance criteria. The simple monitoring plan, <br />as proposed in the document under review, is not an acceptable solution to the likely generation <br />of acid and toxic substances ". <br />CC & VG stated in their December 1, 1994 memo that '7t makes no sense for CC & VG to <br />propose, and bond for, a "cap" in addition to the soil cap that is currently planned and <br />required by the approved permit. The soil cap will certainly reduce infiltration of water <br />