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• hghwall mining areas than the values from the limited ATT testing program. The ATT <br />results for shale and sandstone are consistent with the database, although stiffness values <br />aze significantly lower. <br />Slake durability values for the Wolf Creek floor suggest that trafficability should <br />not be a problem. Results for the Sage Creek floor are lower, suggesting a softer floor. <br />The fact that groundwater is rarely encountered should help with floor stability. <br />3.0 HIGHWALL MINING CONSIDERATIONS <br />Current plans are for Seneca to utilize the Superior Highwall Miner (SHM), <br />owned by Peabody Energy (herein referred to as a PM). This machine is manufactured <br />by Superior Highwall Miners, Inc. (SHM), of Beckley, WV. <br />3.1 System Overview <br />The launch vehicle of the Superior Highwall Miner (Figure 28) is mounted on a <br />set of four hydraulically powered crawlers (Fiscor, 2002). A continuous miner-type <br />cutterhead is Bumped into the seam using two hydraulic cylinders with a 20-ft stroke and <br />380,000 ]b of force. Coal cut by the miner is propelled out of the hole first by a short <br />• chain conveyor, and then by a pair of 18-in-diameter horizontal augers. As each 20-ft cut <br />is completed, the powerhead on the launch vehicle is disengaged from the cutting system, <br />and a 20-ft pushbeam, complete with horizontal augers, is automatically inserted between <br />the powerhead and the cutterhead. This process is repeated until the desired hole depth is <br />realized. At this point, the powerhead pulls the string out of the hole, and pushbeams are <br />removed one at a time. Pushbeams are added and removed from the pushbeam transfer <br />mechanism by a front-end loader equipped with forks. The PM is a rear dischazge ?_ <br />machine, and requires a bench width of 75 ft to 85 ft. <br />" All of the sumping force is provided by the hydraulic cylinders on the launch <br />vehicle; the cutting head is not equipped with crawlers. As such, the miner has no <br />steering capability. <br />Within the operator cab on the launch vehicle, a PLC allows the operator to set <br />cutting height, sumping force, etc., and let the machine mine automatically. Machine <br />performance is observed with a video monitor, and the operator can change mining <br />parameters as warranted. The system is equipped with a methane detector that <br />automatically shuts the cutterhead off if 2% methane is detected. <br />3.2 Mining Parameters <br />NSA contacted the manufacturer, Superior Highwall Miners, Inc., to ]earn the <br />. basic specifications of the PM. NSA spoke with Stewart Myers, Engineering Manager, <br />and Steve Antoline, President. The PM is equipped with a 14CM 15 cutterhead with a 38- <br />in drum. Table 4 lists its basic operational specifications/capabilities. <br />Seneca Coal Company 6 NSA Engineering, Inc. <br />Highwall Mine Design Repon June 2003 <br />