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<br /> <br /> <br />Impact on groundv~ater rights. No surface or groundwater rights have been identified v~ithin the New <br />Horizon 2 mine area. Therefore, there will be no direct impact from the approved mining plan on <br />any local water rights. <br />Impact afspal material on grourxMaterflavand recharge The mine pit will remain open only until <br />the coal has been removed. Following the short-term water level decline on the groundwater system <br />as a result of pumpage of groundwater inflow to the pit, a potential long-term impact to the local <br />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 v~ill be replaced using <br />techniques which will restore pemneabilities of the material. Thus, the mining operation will not <br />diminish vertical or horizontal pemieabilities but may increase these permeabilities. As a result, <br />there should be no significant impacts from the mining operation on groundwater flow 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 post <br />mining land use. <br />Corrtiinment of pit inflow and impacts on water quality. All runoff and pit pumpage from disturbed <br />areas will be routed through sedimentation pond 007. The pond is designed and constructed to <br />impound runoff and pit pumpage from areas disturbed by mining and provide sufficient residence <br />time to insure that the pond discharge water chemistry meets the effluent requirements specified in <br />the NPDES Permit. A review of the chemical and flow data indicates that the potential for any <br />discharge from Pond 007 to exceed receiving stream or federal standards is minimal. Past history <br />of mine operations at the Nucla Mine indicate very few exceedances of the standards over the years <br />of operations. As previously discussed, highest pit inflow is predicted to occur in year 5 at <br />approximately 5,600 cubic feet per day. To assess the impact of this inflow on Calamity Draw and <br />the San Miguel water quality, it was assumed that the entire flow was discharged and that the TDS <br />level for the overburden aquifer was representative of the chemical load. The duration of the water <br />quality impacts is relatively short term (5 years) and the signifcance of the impact is negligible as <br />TDS increases in the range of 0.08 to 1.5 percent are projected on the San Miguel River and <br />Calamity Draw, respectively. These increases in TDS vrill be additional magnesium/sodium-sulfate <br />type water which may result in a slight increase in salinity. These projected changes in TDS levels <br />will in noway affect the present and potential uses of the surface water and are so small that they <br />may not be measurable. <br />(Revised 4596) 2_QQ, 7-44 <br /> <br />