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Probable Hydrologic consequences <br />Ground Water (Cont.) <br />5. Impact of spoil water quality on ground and <br />surface water quality. <br />Surface Water <br />1. Effects of mining on the local geomorphology. <br />2. Effects of sediment ponds on channel <br />characteristics and downstream users. <br />TABLE 2.05.6.(3) -1 (CONT.) <br />CONSEQUENCES OF THE LIFE -OF -MINE MINING PLAN <br />FOR THE NEW HORIZON MINING AREA <br />Analysis Results <br />Geochemical controls on water quality suggest that the <br />water chemistry and concentrations of most elements of <br />concern are controlled by mineralogic reactions that will <br />resist changes in water chemistry. Irrigation water will <br />enter the spoil and will increase in TDS and will <br />discharge from spoil springs but the quality will be <br />essentially the same as the current overburden water <br />quality. This will occurfor at least hundreds of years and <br />the spoil water quality will gradually improve to the <br />quality of the irrigation water as pyrite is oxidized and <br />dissolved solids are flushed out. <br />A stream channel course has been altered, the length <br />has been reduced, and the overall gradient will be <br />slightly increased after the removal of the 001 pond. <br />Watershed areas will increase, elevations and slopes <br />will be reduced, and slope lengths and time of <br />concentration will increase. <br />Channel reaches below the frequently discharging <br />ponds, will become incised with active meandering <br />channels and vegetation will encroach along the <br />channel edges. AVF study indicates that the channels <br />in Tuttle and Calamity Draws are too incised for flood <br />irrigation, hence neither Draw is determined to be an <br />AVF. Surface water impounded by the sediment ponds <br />may affect water rights downstream. <br />Revised September 2014 JR -64) 2.05.6(3) -19 <br />Significance <br />No indication of significant long or short term impacts to <br />the local ground water quality. Impact to San Miguel <br />water quality is of little significance. Impacts to Calamity <br />and Tuttle Draw water quality are measurable, but are <br />of little significance in terms of water use. See detailed <br />discussion in Probable Hydrologic Consequences under <br />Item 5) Potential impacts of replaced spoil on <br />groundwater quality <br />Adequate reclamation and channel design has resulted <br />in a stable channel. Monitoring conducted in the <br />channel since 1980 indicates noadditional contributions <br />of suspended sediment. Watershed impacts will be <br />mitigated by contour ripping, mulching and prompt <br />revegetation. The watershed impacts are expected to be <br />very minimal. Once full reclamation is done on the <br />property by 2014, the site will have no impact on the <br />local geomorphology. <br />Long term channel impacts until bond release followed <br />by short term channel readjustment period when ponds <br />are remove. Impacts are of minimal significance and <br />increased vegetation should help control sediment <br />during channel readjustment period. No mitigation is <br />necessary for AVF's (negative determination). WFC <br />has water rights to more water than required for mining <br />related uses. An augmentation plan has been <br />developed for mitigating any impacts proven on <br />downstream users. <br />