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Vertical permeability of the overburden on the mine property <br /> has been estimated at 0. 00021 ft/day (mine permit application) . When <br /> this low permeability is multiplied by the horizontal surface area of <br /> saturated alluvium of the area, downward flow of water is estimated at <br /> 2. 3 gpm. With the flow measured in the Purgatoire River, this small <br /> water loss would not be detectable. This would also be true for the <br /> Purgatoire alluvium. Flows of the river will continue to replenish the <br /> amount of water lost to seepage. <br /> The effects on the side canyon drainages should be similar to <br /> the Purgatoire alluvium. Based on general geologic mapping , the <br /> alluvial area of each canyon was multiplied by the permeability, the <br /> water lost to seepage in Apache , Ciruela and Santistevan Canyons has <br /> been estimated 0.3, 0. 07 and 0. 09 gpm, respectively. In all cases, <br /> this represents less than one percent of the calculated runoff for each <br /> system. However, in those canyons which have surface entries into the <br /> coal (Ciruela and Apache) , seepage from shafts may add to the alluvial <br /> water loss. The mine inflow studies (Appendix 3) indicate that 19. 4 <br /> gpm entering the Golden Eagle Mine comes from shafts located in Ciruela <br /> Canyon and 8 gpm entering the New Elk Mine comes from shafts located in <br /> Apache Canyon . These flows are significant when compared to the <br /> calculated runoff available for these two canyons; suggesting a <br /> localized impact on surface and alluvial flow of water at the mouth of <br /> each canyon. <br /> In terms of water quality of the Purgatoire River and <br /> associated alluvium, mine discharges and leachate from refuse <br /> contribute to higher ionization of the water and increased amounts of <br /> trace elements. The main parameters of interest are sodium and other <br /> dissolved salts which may effect downstream use of the water for <br /> irrigation. Obviously, these increases will have a greater impact as <br /> flows in the river are low. However, even at low flow conditions, <br /> effects of ionization caused by mining are insignificant when compared <br /> to the natural deterioration of water quality as the river flows to the <br /> east (see Introduction Discussion) . <br /> 17 <br />