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• • III IIIlillllllll III <br />999 <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Deparlmenl of Nalu rdl Resuuree5 <br />1313 Sherman 51., Ruom 215 <br />Dem~er, Cubn~do S1R03 <br />Phone: 13031 R66 3567 <br />FA%: (3031 831-A106 <br />DATE: November 21, 1996 <br />TO: Berhan Keffelew <br />FROM: Harry Posey ~ <br />~I~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />Roy Romer <br />Governor <br />lames 5. Lochhead <br />Eneculrve Director <br />Michael B. Long <br />Division Direcbr <br />RE: Comments, "CC&V Response About Total Sulfur Analyses," Cresson Project, <br />Permit M-80-244. <br />This memo addresses CC&V's response letter of October 26, 1996 regarding the permit conditions <br />and discussions at our recent site meeting. CC&V has provided a synopsis of sulfur data to cover the <br />Division's request. <br />To the present, no acid rock drainage problems or off-site damage from ARD have been identified at <br />this site. Based on rock leach and total sulfur tests provided by the operator, some of the rocks appear <br />to have acid rock drainage (ARD) potential. The abundance of acid generating or metals producing <br />rocks relative to non-acid generating or non-metals producing rocks is not known, and the ability of <br />the groundwater hydrologic system to buffer, dilute, or otherwise reduce metals or acid concentrations <br />to acceptable levels is not known. <br />I would suggest that the operator be advised to evaluate the potential for generation and release of <br />ARD from the pit floor, overburden storage areas, wall rocks, and surface disturbances. Previous <br />submittals do not clearly demonstrate the absence of such potential. This evaluation should predict <br />water quality at the in-place monitoring points, or at present or future points of use. The evaluation <br />should also consider the ability of ambient groundwater to mitigate the effects of rock weathering. <br />Please let me know if this topic needs further examination. <br />cc: Mike Long <br />Bruce Humphries <br />Jim Stevens <br />Jim Pendleton <br />M: \M iN\HHP\S U LFUR2. CC V <br />