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West Elk Mine <br />. Small Capacity Sumps <br />Small capacity sumps are routinely constructed in underground mining operations, including <br />West Elk Mine, during both room-and-pillar and longwall mining operations. In the course of <br />mining, there is a routine need to intercept and store expected groundwater inflows to the mine, <br />as well as imported water after operational use that runs off the mining face. These sumps are <br />typically open depressions or low areas in the developed entries that are deepened to intercept <br />and temporarily store water capacities of less than 1,000,000 gallons (3 acre-feet). Examples of <br />these sumps include three within the B Seam mine workings; one in the northeast corner of the <br />longwall panel (used when the 1NW to SNW panels were mined), the second at the bottom of the <br />F to B Seam slope, and the third in the northeast corner of the IONE and 11NE panels were <br />mined). Other similaz sumps will be developed for the South of Divide longwall panels and all <br />future mining sections. Consequently, the cumulative B and E Seam volume in the small <br />capacity sumps will be less than 12 acre-feet. Given the total annual estimated groundwater and <br />surface water inflows during 1996 to the mine of more than 500 acre-feet, the storage volume is <br />insignificant (<3 percent); consequently, the rest of this section will focus on the large capacity <br />sumps. <br />In addition, an intermediate sized sump was located in the l ONE Tailgate north of the BEM Fault <br />and east of the I ONE Tailgate entries. This sump was constructed and equipped with various <br />pumps as a result of the unprecedented inflows from the BEM Fault and had an estimated storage <br />capacity of 1,200,000 gallons (3.7 acre-feet). Inflows from the BEM Fault flowed by gravity to <br />this sump location. Other waters, both operational runoff and inflows, from the east side of the <br />mine have been pumped to this location as well. From here, the water was pumped to the surface <br />or to the NW Panels sealed sump. The NE Tailgate sump lies within the planned seal line of the <br />lONE and 11NE longwall panels and is operational, dischazging through the Sylvester Gulch <br />facility. <br />Large Capacity Sumps or Sealed Panels Sums <br />Previously mined portions of the mine which are optimally located in down-dip areas where <br />water would accumulate to provide large volume storage of groundwater, such as the anomalous <br />and unexpected inflows experienced from the BEM and 14HG Faults. <br />There are three areas of the mine which are presently being used or are planned to be used as <br />large capacity sumps. Presently, is utilizing the northern end of the 1NW through 7NW <br />longwall panels as one of these large capacity sumps (see Figure 28). This azea is referred to as <br />the NW Panels sealed sump. The second is planned for the area created by the longwall mining <br />of the LONE and 11NE longwall panels (see Figure 28). This sump is called the NE Panels <br />sealed sump. The third sump, the Box Canyon Panels sealed sump, is planned for the area <br />created by the longwall mining of the Box Canyon Panels (i.e., the 18NE through 23NE longwall <br />panels). <br /> <br />2.05-238 Revised November 2004 PR/0 <br />