2009-06-18_PERMIT FILE - C1981018A (6)

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• The drill holes (including vent holes) will be plugged by placing a cement plug in the casing from a depth of 10 feet to the surface. Excessive casing will be removed to about 2 or 3 inches above the surface. An identification cap will be grouted in the top of the remaining casing. This permanent sealing method for drill holes is shown on Figure V-2. If a drill hole is completed through an aquifer, and that aquifer is not lost as a result of mining the plugging will be consistent with Rule 4.07.3(2). Sloping ventilation shafts and portal entries will be plugged by one of two approved methods (Section 4.07.3). The first method utilizes an unreinforced wall of concrete, bricks, the or concrete block 2 feet thick or greater. The second method is to backfill the opening with incombustible material for a distance of at least 25 feet from the mouth. See Figure V-1. All mine entries will be sloped in and the entry faces will be above all ground water levels, therefore ground water cannot exit through the mine entries. The elevation of the bottom of the "D" Portal entries at the face is approximately 5636 feet. The estimated 50 year flood level is 5629 feet, the 100 year flood is 5630 feet, and the 500 year flood is 5632 feet. The elevation at the bottom of the Ventilation Area entries at the face is approximately 5380 feet. The estimated 50 year flood level is 5372 feet, the 100 year flood is 5373, and the 500 year flood is 5375 feet. All of the proposed entries are above the 50 year, 100 year and 500 year floods, therefore no surface water is likely to enter the mine entries. Also the sealing method proposed for the sloped entries will prevent any significant amounts of water from entering the mine after abandonment. (Estimated flood levels from the U.S. Army Corps of Engineers). The B-Vent Shaft opening was found to be well above the flood line of the Scullion Gulch during an inspection by DMG. Vertical shafts will be filled for the entire depth of the shaft and, for the first 50 feet from the bottom of the coalbed, the fill shall consist of incombustible material. Surface facility demolition rubble may be used for fill if suitable and available. Coal refuse may be used above the first 50 feet from the bottom of the coalbed. See Figure V-2. All vertical shaft openings will be above any possible flood levels. This plan applies to the B-Vent Shafts and other large diameter shafts. RS-1 and RS-2 were filled in 2003 in response to a heating incident in the gob. Incombustible fill material was barrowed from the RS-2 pad to fill both shafts. RS-1 pad was recontoured and seeded that fall. The fill material from RS-2 was replaced by material generated from recontouring County Road 65 -Haul Road intersection. Sufficient material was also hauled from this intersection to RS-3 to plug the full depth of the hole at a later date. A plan for mine sealing will be submitted to and approved by MSHA before the shutdown of any major mine ventilation system. All mine openings large enough for human access required for monitoring or for ventilation purposes which are located in areas without controlled access will be adequately fenced or posted with conspicuous signs prohibiting the entrance of unauthorized persons. • Minor Revision #139 (12/2008) V-18