1986-03-03_REPORT - C1981013 (4)

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of water at the mouth of each canyon. Further studies will be conducted during 1985 to estimate more precisely the vertical and lateral extent of side canyon alluvial aquifers. From this work additional assessments will be made regarding mining impacts on the hydrologic balance. In terms of water quality of the Purgatoire River and associated alluvium, mine discharges and leachate from refuse contribute to higher ionization of the water and increased amounts of trace elements. The main parameters of interest are sodium and other dissolved salts which may effect downstream use of the water for irrigation. Obviously, these increases will have a greater impact as flows in the river are low. However, even at low flow conditions, effects of ionization caused by mining are insignificant when compared to the natural deterioration of water quality as the river flows to the east (see hydrologic assessment as presented in the 1981 permit application). Water quality in side canyons of the river should not be effected by mining operations because of limited surface disturbance contributing to water quality deterioration. Assessments of springs and seeps (Appendix 3) and area water users (Appendix 5) indicate that mining at the New Elk and Golden Eagle Mines should not effect current uses of surface and ground waters. 4.0 MITIGATIVE MEASURES Various designs of mine operations and facilities have been incorporated to minimize disturbance of area hydrologic function at the New Elk and Golden Eagle Mines. The primary mitigative measure is the surface water control plan which is discussed in the 1981 mine permit application. This plan provides for the implementation of ditches and impoundment structures which control the quantity and quality of runoff generated from the mine affected area. These affected areas include mine discharges, refuse disposal areas, coal stockpiles and sediment control from disturbed areas. -26-