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In the event the highwall proves to be unstable over the entries either a steel arch, mats, and/or concrete will be <br />installed to stabilize the area. The entries will be driven from the Main North workings, and approximately 13,000 <br />tons of coal will be mined during the development of these entries. The entries will be approximately 900 feet in <br />length. The location of the entries is shown on Map 23. <br />When the entries are no longer needed, they will be sealed consistent with the procedure outlined on page 2.05-119, <br />by constructing seals consistent with the approved "typical seal" design as shown on Figure 15. After construction <br />of the seals is completed, the site will be backfilled in accordance with the approved plan. No additional work, <br />except for seal construction, will be required as a result of developing the eastern portals. <br />Minim Method <br />The mining method planned for the Foidel Creek Mine is a combined system of room and pillar and longwall <br />mining. Both mining methods are successfully used in western U.S. coal operations having similar mining <br />conditions. <br />Room and Pillar Minine <br />Room and pillar mining refers to the extraction of rooms (mine openings), while retaining unmined pillars of coal <br />for support, using a continuous mining machine. Rooms are mined on development and the pillars are partially <br />extracted during retreat. This mining method has been the backbone of the U.S. coal mining industry and it owes <br />its popularity to its relatively low cost and flexibility. This method easily adapts to changes in the geological and <br />physical conditions of the mine. Continuous miners can negotiate tectonically disturbed areas of the mine and <br />adapt to seam variations and uneven reserve blocks. The continuous miner section equipment can be easily and <br />quickly transported to different locations in the mine, and total production is only proportionately affected by <br />stoppages of any one unit. <br />The productivity of a continuous miner unit in room and pillar extraction is less than longwall mining under most <br />conditions and thus more expensive in operating cost-per-ton. The overall coal recovery for room and pillar mining <br />seldom exceeds 55 to 60 percent, due to the necessity to leave barrier pillars and pillar stumps. <br />LonQwall Minin <br />Longwall mining has gained great acceptance and is increasing in popularity in the U.S., primarily because of its <br />inherent advantages of high productivity, low operating cost, high reserve recovery, and improved worker safety. <br />Longwall mining derives its name from the several hundred-foot long faces from which coal is cut. Longwall panels <br />are large blocks of coal laid out several thousands of feet long by several hundreds of feet wide. Extraction occurs <br />using a powerful cutting machine with rotating drums which cut slices of coal from the face of each panel. All work <br />takes place under a canopy of hydraulic steel supports. The roof supports are closely placed side-by-side in a straight <br />line to separate the working face from the caved area behind the shields. The cutting phase is followed by advance of <br />the steel supports in a continuous cycle of operation. As the shields move forward, the unsupported roof behind the <br />shields caves, relieving roof stress. Longwall mining achieves upward of 75 percent recovery because the entire seam <br />is extracted in major blocks. <br />Production <br />Annual production levels will be dictated by market demand and as such, are subject to yearly adjustments. Table <br />46, Production Schedule, shows current estimated annual production for the life of the operation. Production began <br />in 1983 with 21,500 tons mined. Production for 1984 was 187,492 tons. Production has subsequently ramped-up <br />with increasing demand for coal, and is expected to reach the maximum production level of 12,000,000 tons per <br />year in 2008, contingent on required facility upgrades and obtaining all necessary related permit approvals prior to <br />increasing production above currently permitted levels. <br />TR06-52 2.05-9 06/27/06 <br />