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been reclaimed, water qualities will return to pre-mining conditions over time. <br />During and after mining, [he exposed disturbed soils and rock strata will impact the <br />quality of ground water in aquifers within the permit and hydrologically adjacent <br />areas. Pit waters and deep percolation through spoils and the fill will impact <br />ground water qualities during mining. The degree of impact to ground water <br />quality depends on: 1) the residency time of water exposed to disturbed soils and <br />rock strata and 2) the residency time of spoils waters and pit waters within the <br />recharge area ofthe aquifers. <br />The coarse fill and spoils materials will allow rapid infiltration and deep percolation <br />of surface waters. Water which infiltrates the spoils will flow down the dip of the <br />spoils-bedrock contact to the low end of the pit during mining, be discharged to <br />sediment pond 1 and then to the stream. The flow rate of infiltrating waters to the <br />pit will be rapid and exposure time will be minimal. Thus, water quality <br />degradation will be minimal. <br />The residency time of spoils and pit water over aquifer rechazge areas will be <br />minimal during the mining operation, since water collecting in the pit and water <br />stored in sediment ponds will be discharged to the surface stream. <br />After the pit and fill slopes have been backfilled and reclaimed, a spoils water <br />aquifer will be established within the rechazge area of the bedrock aquifers. <br />infiltration will be minimized due to the construction of a compacted impermeable <br />layer of clay and silt beneath the reconstructed stream channel. The extent of <br />degraded spoil water incursion into the aquifers will be minimal. Dilution and <br />dispersion by ground water within the aquifers will further diminish the water <br />quality impacts. <br />Wastes from the coal facility could potentially impact the quality of surface and <br />ground water. The sulfur content of the coals and their associated over and <br />underlying strata range between'/z and 3 percent. These levels are higher than <br />most active coal mines in the State of Colorado. Also, abandoned coal mine <br />records for the Durango, Colorado, area document problems with acid mine waters <br />and barren and burned spoil piles. Both of these facts indicate that the coal <br />processing wastes generated by the Carbon Junction Mine will probably be <br />acid-forming and have a high probability of being combustible and toxic-forming. <br />Coal processing wastes will be trucked to two temporary storage piles above the <br />proposed pit highwall. Surface runoff from the piles will be diverted into the pit <br />and eventually discharged after meeting NPDES discharge requirements. The <br />waste piles will be approximately 10,000 cubic yards, and hold wastes until the pit <br />has been backfilled above the level of the reconstructed stream channel. The <br />wastes will be pushed in the pit by dozers once the pit has reached an elevation of <br />is <br />