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<br />i <br />coal exiting the mine, and in increased humidities in the ventilation <br />air. Currently, coal is not exiting the mine and ventilation air volumes <br />are reduced. <br />Mining activity might affect the stream/alluvial aquifer system of the <br />Middle Fork of the Purgatoire River. The Allen and Maxwell coal seam <br />aquifer subcrops below the Middle fork of the Purgatoire River and in <br />Pete Canyon, north of the New Elk Mine. These streams and their alluvial <br />aquifers may recharge the coal aquifer. If so, the underground mine <br />workings may diminish the stream/alluvial aquifer systems through <br />increased recharge at subcrops and outcrops of the coal aquifers. <br />Dimunition of stream/alluvial aquifer systems may also occur as a result <br />of drying up of aquifer discharges (springs and seeps). Any excess water <br />entering the coal aquifer, however, is returned to the Purgatoire River <br />via the discharge of water from the mine. Impacts on quantity of water <br />available from the stream/alluvial system of the Purgatoire should be <br />minimal. <br />Impacts to Pete Canyon are expected to be short-term in nature. Once <br />mining ceases, pumpage of mine water will be stopped and the mine will <br />begin to fill. After filling of the mine, dimunition of water from the <br />surface system of Pete Canyon should cease and flows return to <br />essentially the pre-disturbance levels. <br />The applicant has predicted that the stream/alluvial aquifer system will <br />be depleted by vertical leakage of surface waters through the overburden <br />strata into the mine cavity. For the New Elk Mine, however, downward <br />flow through the overburden in the absence of open fractures or <br />subsidence was calculated to be less than 5 gpm, an insignificant portion <br />of flow in the Purgatoire River stream-alluvial aquifer system. <br />Inspection of underground workings in the New Elk Mine beneath the Middle <br />Fork by Division personnel did not identify significant inflows of ground <br />water that could be attributed to leakage through the roof from the <br />stream/alluvial aquifer system. <br />An annual inflow study for the New Elk Mine was initiated in 1983 and <br />most recently conducted in August of 1987. This study consisted of the <br />mapping of all measurable mine inflows on a mine workings map, measuring <br />or estimating inflow rates, and determining inflow sources. The most <br />current information on the New Elk Mine inflows is contained in Exhibit <br />10 of the renewal application. <br />Mine inflows are not concentrated in areas of the New Elk Mine which are <br />overlain by streams, but are dispersed throughout the mine. Thus, the <br />mine does not appear to have significant direct connection with the <br />stream or alluvial system. <br />The mapping of mine inflows indicate that faults and fractures are not a <br />source of mine inflows. No point source inflows were observed along <br />faults and fractures. This indicates that faults and fractures are <br />healed with impermeable clays and/or are not vertically extensive. <br />-22- <br />