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increase slightly since water from the ditch would provide additional infiltration, however, the ditch <br />area is so small (0.87 acres) compared to the area of the spoil (768 acres) and the area of irrigation <br />(422 acres), thatthe increase in infiltration would be negligible. Therefore, the worst case prediction <br />for flow in the spoil spring at the New Horizon #2 Mine is 952 acre feet per year, while the most <br />realistic flowfor the spoil spring is 490 acre feet per year. This is a potential flow of 1.31 cfs (worst <br />case) and 0.68 cfs (realistic case). <br />In both cases, the flow is higher than the previously calculated spoil spring flowfrom when the New <br />Horizon #2 mine covered a smaller area. That flowwas 0.57 cfs. The greater flow at New Horizon <br />#2 mine will lead to a lower impact on area water quality due to dilution. <br />Overall, there should be no detrimental impacts from the mining operation on groundwater flow <br />and recharge rates. It is definite that ground water flow and recharge in the spoil material will be <br />increased, since the overburden aquifers have historically had very low flow rates and also poor <br />quality. These aquifers have not been used for any wells in the surrounding area and cannot be <br />considered a water resource. The ground water aquifers below the Dakota coals, in the Burro <br />Canyon Formation, are used in surrounding wells and have better water quality buttheywill not be <br />affected by the mining and reclamation of this site. Shale layers below the mined coals prevent <br />interaction between the spoil and these aquifers, which get their recharge from long distances away <br />from the mine operation. <br />Revised August 2010 (PR06) 2.05.6(3) -25 <br />