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• 3.1.4.2 Highwall Mining <br /> Highwall mining is slated to occur to the east of East Ashmore pit and the Galling dip pit in 2006 and <br /> 2007. In East Ashmore pit the H seam on the floor of the last cut will be highwall mined prior to <br /> backfilling and regrading. In Gatling dip pit both the K and Q seams will be highwall mined. The two <br /> seams may be mined top-down or bottom-up depending on geotechnical considerations and the <br /> sequence of stripping and mining operations. <br /> In addition, highwall mining may be conducted in the end walls of the East Ashmore, Galling, Derringer <br /> and Flintlock pits if further geologic and geotechnical studies demonstrate feasibility, and the timing of <br /> stripping operations allows access. In the East Ashmore pit end wall the H seam would be mined. In the <br /> n di pit end wall the K andlor_the_M.and/or the Q seam would be mined. In the Derringer pit end <br /> wall the Q1 seam would be mined. In the Flintlock pit end wall the M and/or the Q seam would be mined. <br /> Use of Mining Technologies' HW H800 Addcar System is planned. A launch vehicle platform, which sits <br /> on the floor of a conventionally mined cut, controls all functions of the system, rigid conveyor cars,which <br /> are each fitted with their own belt conveyor, are fed by a full sized conventional, remote controlled <br /> underground continuous miner. Video cameras placed on the miner give real time feedback to the <br /> outside operator, a proprietary HORTA Guidance System gives continuous three dimensional locations, <br /> and Gamma Sensors in the miner's cutting head provide the ability to sense roof and floor rock and help <br /> keep the miner in the coal seam and avoid,dilution from the roof and floor. <br /> Depth of penetration and coal recovery will vary depending on coal seam splitting, thinning or pinching, <br /> coal quality, roof and floor integrity, and machine physical limitations. Penetration depths of up to 1_:400 <br /> feet are possible under optimal conditions; however with Trappers thin and steeply dipping coal seams <br /> much shorter penetrations are anticipated. <br /> • Trapper is not currently aware of any abandoned or active underground mine workings in any of the <br /> pertinent coal seams in the proposed highwall mining areas. In the event abandoned or active <br /> underground mining operations are identified, no highwall mining will be conducted within 500 feet of <br /> previous workings in the applicable seams. <br /> ✓Trapper is also not aware of any dwellings, buildings, tanks, impoundments or utilities overlying areas <br /> planned for highwall mining. <br /> Access to highwall miner entries will be blocked or buried within 30 days following coal extraction. <br /> Any highwall mining entry discharging water containing toxic-forming or acid-forming material will be <br /> plugged within 72 hours after completion by backfilling and compacting non-combustible and impervious <br /> material into the hole to a depth sufficient to form a water-tight seal or the discharge will be treated <br /> within 72 hours after completion to meet applicable effluent limitations and water quality standards. <br /> s <br /> 3-15b <br />