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

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West Elk Mine • plan view) matches the panel outline on the north and east with a southwestern boundary perpendicular to the dip of the coal seam (i.e., from northwest to southeast). In the Box Canyon Panels sealed sump, the storage area is defined by the panel outline on the north and the strike of the coal seam on the south. In this portion of the mine, the coal dips neazly due north. All three sumps' southern boundaries are predicated by the elevation of the existing or proposed seals. Because of the dip on the coal seam, the deepest portion of the NW and NE Panels sealed sumps is in the northeast corner, and is in the northwest corner of the Box Canyon Panels sealed sump. In the NW Panels sealed sump this depth is approximately 65 feet below the seal elevation, in the NE Panels sealed sump the depth will be approximately 120 feet below the seal elevation and in the Box Canyon Panel sealed sump the depth could be as much as 270 feet. Details of these large capacity sumps are as follows: 1VW Panels Sealed Sump Mining began in the 1NW longwall panel in 1992. Operational water used for cooling and dust suppression on the longwall face was allowed to flow down-dip to an operational sump at the northeast comer of the 1NW panel The water was then pumped to the slope sump and out of the mine to the sedimentation ponds. This practice continued during mining of longwall panels 2NW and 3NW. Water management changed slightly while mining the 4NW and SNW longwall panels. Since all water would not flow via gravity along the dip to the northeast corner of 1NW, water was pumped M with air-powered pumps from each of the northeast corners of the 4NW and SNW panels to the north end of the 3NW panel where it would gravity flow to the northeast corner of 1NW and then was pumped out of the mine, as above. In addition, process water from development mining in the Jumbo North Mains and small inflows below Dribble Gulch were pumped into the southwest corner of the 3NW panel at crosscut 29 in the B West Mains while longwall mining the 4NW and SNW panels. Water from this location flowed via gravity through the caved INW through 3NW panels, along the dip to the northeast comer of INW and then was pumped out of the mine, as above. Small, isolated groundwater inflows were encountered during mining of the INW through SNW longwall panels. Initial inflows were typically on the order of 5-10 gpm and typically stopped flowing within a few days. Upon completing longwall mining of the SNW panel, removed the pumps and terminated access to the operational sump in this azea by constructing ventilation seals, as required by MCC's MSHA approved Ventilation Plan. Panels 1NW through SNW were completely sealed in May 1995. Therefore, the minor groundwater inflows and the process water from outside this sealed area that was pumped in through crosscut 29 began to accumulate within the 1NW through SNW panels in May 1995. Ventilation seals were constructed across entries and crosscuts to block gas movement from the previously mined 1NW through SNW longwall panels to the fresh air systems in the B West Mains and active mining sections. These seals are constructed specifically for ventilation purposes. Atypical seal is comprised of wood block or cribbing approximately 30 inches thick onto which is blown approximately 4 to 6 inches of expansive foam as a sealant. While this construction is an effective ventilation seal, it is not designed to be an effective hydraulic seal. A 2.05-28( Revised June 2005 PRIO; Rev. March 2006; Rev. May 2006 PRI G