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West Elk Mine <br />Historically, the water pumped to Ponds MB-1 and MB-2R and water retained in the product <br />.~ and gob have been the most significant mine outflows (57.3 and 111.0 acre-feet, respectively, <br />in water year 1995). With the fault inflows, discharges from the sealed panels sumps to Lone <br />Pine Gulch and/or Sylvester Gulch will likely become the dominant mine water outflows. <br />As a result of pumping water into the NW Panels sealed sump (and eventually the NE and Box <br />Canyon Panels sealed sumps), minor groundwater seepage through the unmined coal from the <br />down-dip (north) ends of the panels could potentially occur. The Groundwater Quantity <br />section demonstrates that the calculated "worst case" amount of water (with the sealed sump at <br />full capacity) leaving the NW Panels sealed sump would be 0.7 to 8.4 gpm. Importantly, the <br />actual sump outflow rate is defined to be perhaps less that the lowest calculated rate of 0.7 <br />gpm per MCC's actual experiences. These include the relatively dry mining faces immediately <br />prior to the high pressure fault inflows, and most importantly, in early 1998, after drilling the <br />NW Sump #1 horizontal drill hole 215 feet, the first water was encountered just 17 feet from <br />the filled sealed sump (with approximately 65 feet of water head). <br />In-Mine Storare -The Groundwater Quantity section discusses the use of the mined NW, NE, <br />and Box Canyon Panels for water storage. The NW Panels sealed sump became especially <br />important when development mining in the 14SE Headgate intercepted a large fault inflow in <br />January 1997. <br />`~ <br />Beginning in late 1998, a new mine water pumping facility located in Sylvester Gulch will <br />have the capability to dischazge up to 2,000 gpm on a consistent basis, in full compliance with <br />the NPDES permit limitations. Then, most mine water runoff and inflows will be collected, <br />conveyed to the NE Panels sealed sump, and then pumped from the mine for dischazge to <br />Sylvester Gulch through the new mine water pumping facility. The pumping facility will have <br />the capability to be expanded to include a treatment system, if necessary. <br />Surface Water Quality EKects <br />Potential effects on surface water quatity from mining (relative to the overall mine) could <br />occur from: (1) runoff from disturbed areas, (2) seepage from waste rock or coal refuse piles <br />to the stream aquifer system, (3) discharge of mine water, (4) discharge of sanitary <br />wastewater, and (5) subsidence-related factors. For the Apache Rocks and Box Canyon permit <br />revision azeas specifically, factors (3), (4), and (5) apply. <br />Runoff From Disturbed Areas <br />I'• <br />Runoff due to rainfall or snowmelt from disturbed azeas would have a higher amount of <br />suspended solids and associated pollutants than undisturbed areas. However, it is required that <br />runoff from all disturbed azeas be detained in sediment control ponds or a similar system, and <br />the dischazges from the ponds comply with NPDES effluent limitations. In addition, disturbed <br />areas aze re-vegetated, which reduces sediment levels. <br />2.05-188 Revixdhm. 1995 PRO6: RevisedNm. 19987880; !/98 PROS <br />