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~: <br />[he sediment ponds or the sewage lagoons. <br />Surface WaterOuality <br />Possible hydrologic impacts on quality of surface water due to tfte Roadside and Cameo Mines <br />include impacts [o: <br />I. Colorado River water due to mine water discharge, and <br />2. Runoff from surface disturbance. <br />As discussed in Section C.II.A. of this document, Powderhom Coal Company has <br />submitted a report to the Colorado Department of Health (CDOH) addressing [he <br />feasibility of diminishing salt contribution to the Colorado River. This report was prepared <br />as required by the mines' NPDES permit and has been reviewed by the Colorado <br />Department of Health at this time. CDOH has determined that no action be required of <br />Powderhom Coal Company to reduce salt contributions to the river and has exempted the <br />Roadside Mines from specific numeric limitations or construction of new treatment <br />facilities. Quarterly total dissolved solids monitoring is still required. <br />Mine discharge from the Roadside Mines were estimated to increase soluble salts in [he <br />river by 0.1 percent and dissolved iron by 0.2 percent (November 4, 1982 DMG Findings <br />Document). These predictions have proven to be accurate to date. <br />[n its 1982 Findings, [he Division also predicted that water quality effects would be <br />"minimal and will not significantly decrease water quality in the Colorado River." Surface <br />and groundwater monitoring to date (February, 2000) have supported these <br />projections. <br />Water monitoring conducted by Powderhom since 1982 has not identified any <br />unanticipated effects on river water quality. Portions of the water monitoring plan were <br />suspended when the mine was placed in temporary cessation from 1987 to 1989. Mine <br />water discharges from the four approved NPDES points for mine water discharge will be <br />analyzed annually for the list of parameters in Table 18-2 of the permit. <br />2. Surface water runoff from disturbed areas on the mine site passes through sediment ponds, <br />with the exception of the small areas discussed in Section C.li. A. of this document. <br />Discharges from these ponds have historically met effluent limits in the mines' NPDES <br />permit except for discharges related to severe storm events. Effects on water quality due <br />to disturbed-area runoff have been and should continue to be insignificant. <br />Groundwater <br />Groundwater Ouali <br />Four hydrologic units have been identified as aquifers that may be effected by the mining <br />operation. These are: Colorado River alluvium, strata overlying the Cameo coal seams, Cameo <br />coal seams, and the Rollins sandstone unit. Each of these will be addressed below as to the <br />mines' probable hydrologic impact. <br />33 <br />