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Draws in the vicinity of the pit will be decreased,~but will be offset by pumpage from the pit. <br />Simulated average daily pit inflow for the coal and overburden aquifers varied from 1,255 cubicfeet <br />per day in year 1 to 5,604 cubic feet per day in year 5. W FC's approach to these potential impacts <br />is to monitor the aquifers and discharge from the pit to determine the extent of drawdown. The <br />hydrological monitoring program should provide reasonably accurate measurements of effects of <br />mining. Should the monitoring show that impacts to the groundwater aquifers are precluding its <br />use, WFC will provide alternate water sources of comparable quantity and quality. As described <br />in the water augmentation plan, WFC has a 114 acre foot consumptive use right on the Highline <br />Canal which would be used to mitigate the potential 26 acre foot impact on surface water right <br />users from pit inflow drawdown. <br />Impact on groundwater rights. No surface or groundwater rights have been identified within the <br />New Horizon 2 mine area. Therefore, there will be no direct impact.from the approved mining plan <br />on any local water rights <br />Impact of spoil material on groundwaterflow and recharge. The mine pit will remain open only <br />until the coal has been removed. Following the short-term water level decline on the groundwater <br />system as a result of pumpage of groundwater inflow to the pit, a potential long-term impact to the <br />local groundwater flow is the period of time necessary for resaturation of the spoil material and <br />reestablishment of aflow gradient. Spoil material at the New Horizon 2 mine will be replaced using <br />techniques which will restore permeabilities of the material. Thus, the mining operation will not <br />diminish vertical or horizontal permeabilities but may increase these permeabilities. As a result, <br />there should be no significant impacts from the mining operation on groundwaterflow and recharge <br />rates. The time period required for the spoil material to resaturate should be greatly reduced <br />because of the irrigation recharge as the mined area will be revegetated for an irrigation type of <br />post mining land use. <br />Containment of pit inflow and impacts on water quality. All runoff and pit pumpage from <br />disturbed areas will be routed through sedimentation pond 007. The pond is designed and <br />constructed to impound runoff and pit pumpage from areas disturbed by mining and provide <br />sufficient residence time to insure that the pond discharge water chemistry meets the effluent <br />requirements specified in the NPDES Permit. A review of the chemical and flow data indicates that <br />(REVISED 25 JuI 2002) 2.04.7-47 <br />