2022-09-29_PERMIT FILE - C1980007 (2)

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West Elk Mine Small Capacity Sumps Small capacity sumps aze routinely constructed in underground mining operations, including West Elk Mine, during both room-and-pillar and longwall mining operations. In the course of mining, there is a routine need to intercept and store expected groundwater inflows to the mine, as well as imported water after operational use that runs off the mining face. These sumps are typically open depressions or low areas in the developed entries that are deepened to intercept and temporarily store water capacities of less than 1,000,000 gallons (3 acre-feet). Examples of these sumps include three within the B Seam mine workings; one in the northeast corner of the longwall panel (used when the 1NW to SNW panels were mined), the second at the bottom of the F to B Seam slope, and the third in the northeast corner of the lONE and 11NE panels were mined). Other similaz sumps will be developed for the South of Divide longwall panels and all future mining sections. Consequently, the cumulative B and E Seam volume in the small capacity sumps will be less than 12 acre-feet. Given the total annual estimated groundwater and surface water inflows during 1996 to the mine of more than 500 acre-feet, the storage volume is insignificant (<3 percent); consequently, the rest of this section will focus on the lazge capacity sumps. In addition, an intermediate sized sump was located in the l ONE Tailgate north of the BEM Fault and east of the LONE Tailgate entries. This sump was constructed and equipped with various pumps as a result of the unprecedented inflows from the BEM Fault and had an estimated storage capacity of 1,200,000 gallons (3.7 acre-feet). Inflows from the BEM Fault flowed by gravity to this sump location. Other waters, both operational runoff and inflows, from the east side of the mine have been pumped to this location as well. From here, the water was pumped to the surface or to the NW Panels sealed sump. The NE Tailgate sump lies within the planned seal line of the IONE and 11NE longwall panels and is operational, discharging through the Sylvester Gulch facility. Large Capacity Sumps or Sealed Panels Sumps Previously mined portions of the mine which are optimally located in down-dip areas where water would accumulate to provide lazge volume storage of groundwater, such as the anomalous and unexpected inflows experienced from the BEM and 14HG Faults. There are three azeas of the mine which are presently being used or aze planned to be used as lazge capacity sumps. Presently, is utilizing the northern end of the 1NW through 7NW longwall panels as one of these large capacity sumps (see Figure 28). This azea is referred to as the NW Panels sealed sump. The second is planned for the area created by the longwall mining of the IONE and 11NE longwall panels (see Figure 28). This sump is called the NE Panels sealed sump. The third sump, the Box Canyon Panels sealed sump, is planned for the area created by the longwall mining of the Box Canyon Panels (i.e., the 18NE through 23NE longwall panels). 2.05-278 Revised June 2005 PRl0; Rev. March 2006