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~ II ~I~~I~II~~~~~~I~ <br />~ 999 <br />S TPTE OF GOLORA00 NIC n:.Rn n. L.~Mti, f: ^~. ~~~~^~ <br />DEPARTMENT OF NATURAL RESOURCES <br />D. Monte Pascoe, Eaecu rive Director <br />IVIL~'ED LAtiD RE~:LAIii~+,'TID:O <br />423 Centennial Builtling, 1313 Sherman Street <br />Denver, Colorado 80203 Tel. (30~) 866-3567 <br />David C. Shelton <br />Director <br />D1 E M 0 <br />T0: Dan f4athews <br />FROM: Jerry Zimpfer~y,., <br />RE: Grassy Creek Mine, <br />DATE: P1arch 11, 1983 <br />Adequacy Review <br />I have reviewed the Grassy Creek Mine permit application which includes <br />material updated August, 1981. f9y review has identified several areas <br />where additional information should be provided so that the Division can <br />write a findings document. <br />Hydrology <br /> <br />1. The application does not contain a spring and seep survey. The <br />applicant should provide a map showing the location of all springs and <br />seeps in the permit and adjacent area. In addition, as required under <br />Rule 2.04.7(2)(a), the applicant should provide sufficient baseline <br />information to identify the seasonal variations in water quality and <br />quantity for the springs. <br />2. The applicant has indicated that mining operations could effect <br />water quality in Grassy Creek (p. II. F-3). 4later percolating through <br />the mined area would discharge as springs and seeps in the Grassy Creek <br />drainage. This discharge would raise the concentration of total dissolved <br />solids in Grassy Creek. The applicant should provide a quantitative <br />estimate of this effect on the Grassy Creek stream/alluvial aquifer <br />system under normal seasonal fluctuations. In addition, the applicant, <br />should identify downstream water users that could be affected, and -. <br />propose mitigations, if appropriate. <br />(Dan - If the applicant does not provide this assessment, the Division <br />should make its own worst-case estimate when findings are written for <br />this operation.) <br />3. The application indicates that the baseline surface water monitoring <br />program would be reduced following the collection of one year's data. <br />Other aspects of the operations surface and ground water rronitor•ing ar•e <br />not discussed. The applicant should provide a plan for the collection, <br />recording, and reporting of ground and surface water quality and quantity <br />