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RRtionale-Recommendation forApproual July 26, 2000 Page 5 this amendment reclamation warranties for future ancillary disturbances. Therefore, the Division believes the operator is incompliance with the above-cited Rules and the Acts. 6.4.6 Exhibit G - tiYaler Information 1 i. Failure to analyze the full spectrum of constituents released from the VLF. (J. Berman, J. T. Cobb , E. C. Mangold, A. Weiland, K. Hughes, R. Flynn (CFV), and R. Fay) DMG Response: In considering information for both Amendments 7 and 8, the Division evaluated the constituents that are regulated in surface and groundwater. The information reviewed included analyses of rocks and waters from the project developed for CC&V, information in the files of the CDPHE and EPA and published information. Mineralogical reports provided trace element inferences. From a regulatory perspective, the primazy geochemical constituents of concern were found to be WAD cyanide and acid rock drainage (ARD). ARD parameters of primary concern were determined to be zinc and pH. Elevated concentrations of Cu, (copper) AI,(aluminum) and Mn,(manganese) were found, though only in rare cases. All these are monitored through the combined ground and surface water monitoring programs of DMG and the CDPHE. In addition, other parameters are monitored in groundwater for indications of ARD generation. 12. The magnitude of the problems with AMD will probably not be known for years. The permit application recognizes that a large portion of the rock to be excavated will be acid-generating. However, the proposed activities will not provide adequate segregation of the waste rock and/or the necessary monitoring and controls to prevent toxic materials and acid from being released to the surface and groundwater. (R. Fay, A. Weiland, K. Hughes, R. Flynn, R. Fay) DN/G Response: The combined test and monitoring data indicate that waste already placed in Arequa Gulch has a net neutralizing potential. Future water that drains through waste rock into the diatreme likely will be neutralized by carbonate in the lower part of [he diatreme. Waste rock materials from the North Cresson and East Cresson are reported to have lower net neutralization potential (NNP) values. However, change from these waste materials will also be neutralized by carbonate in the lower part of the diatreme. 13. Apparently some of the mine pits will be backfilled but backfilled materials may leach acid-forming materials. This does not comply with the Rule. Also, backfill should be done to produce controlled drainage to surface water treatment facilities, rather than uncontrolled leaching to subsurface tunnels and other release conduits. Reliance on the Carlton tunnel [o supposedly neutralize leachate from backfilled pits does not comply with Rule 3.1.5(2). The Rule specifically prevents any backfilled materials from "leaching...acid-forming materials." This is a very strict standard, arguably much more difficult to meet than the general requirement that the leachate meet all water quality requirements. (R.M. Raub, S. Crowner, R. Batiste) DMG Response: ARD may be produced from some of the pit backfill, but high NNP values in the lower part of the diatreme should result in neutral ground and surface waters at the first points of use. Above the water table, which in the mine area occurs at slightly above the Carlton Tunnel level, there is no groundwater use and no means of regulating unsaturated zone waters. 14. CC&V should ensure all water quality standards will be met. The MLRB cannot approve an operation unless the applicant has provided evidence the operation will at all times be in "compliance with applicable federal and Colorado water quality laws and regulations...", Rule 3.1.6. At a minimum, CC&V must analyze, test for, and assure full compliance with all of the standards for