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<br /> <br />Requirement <br />Requirement <br />citation Require- <br />ment <br />complied <br />with ? <br />es / no <br /> <br />Comment <br /> Pages 2.05-185 through 293 of the permit application predict the probable hydrologic consequences <br /> that will be caused by mining at the West Elk Mine, as summarized below. <br /> 1) Surface cracks may encounter surface water resources and cause impacts that are temporary and <br /> insignificant. <br /> 2) No subsidence effects will be seen at Minnesota Reservoir. <br />V. Agreement of CDRMS 3) Subsidence may increase stream erosion rates by amounts of less than 5%. <br />observed regulation 4) The caved/fracture zone may intercept ground water-bearing stratigraphic units overlying the coal <br />hydrologic 2.05.6(2) and seam, resulting in initial mine inflows of ground water of 10 to 15 gpm, which will taper off to a <br />impacts with requirement trickle in a few weeks. <br />"probable to keep yes 5) Inter-strata] mixing of ground water via subsidence fractures may occur, but the impact to quality <br />hydrologic <br />" information <br />will be negligible. <br />consequences <br />(PHC) projected current, <br />CDRMS 6) Flows from natural springs located in the Dry Fork basin may decrease in flow rate, move to new <br />in mining regulation locations, or dry up. (The operator plans to mitigate any of these impacts that are significant.) <br />permit 2.03.3(1) 7) The mine's discharges (from ponds and mine pumping) to the North Fork of the Gunnison River <br /> will not cause exceedances of the instream standards for total iron or pH. Instream TSS will <br /> continue within its historical range. TDS may be significantly elevated, temporarily, in an extreme <br /> worst-case scenario, but will not continue long enough to reduce crop yields. <br /> Review of the 2007AHR found that impacts have been consistent with the impacts predicted in the <br /> existing PHC and, therefore, updating the PHC is not warranted. <br />W. Adequacy of Existing monitoring appears adequate. Bedrock ground water monitoring wells are positioned to <br />ground water CDRMS <br />regulation yes intercept leachate flow at the two locations most likely to be in the leachate flow path, should leachate <br />monitoring 4.05.13(1) migrate down-gradient from the mine workings after they are flooded. Alluvial monitoring wells are <br />program properly located for assessing impacts to the North Fork of the Gunnison River. <br />Page 7