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West Elk Mine <br />subsidence (rather than natural) cracking would be minimal. MCC will conduct visual inspections <br />of primary public access to the USFS lands on a monthly basis, weather and ground conditions <br />allowing, when these roads could be potentially impacted by undermining. MCC will mitigate all <br />roads that may have been impacted due to subsidence and provide signage, particularly on public <br />roads, warning of potential hazards. <br />Subsidence Prediction — 2.05.6 (6)(e)(i) <br />Brief Description of Mining Method - 2.05.6 (6)(e)(i)(A) <br />Apache Rocks and Box Canyon Mining Areas - The longwall mining method was utilized in the <br />Apache Rocks and the Box Canyon mining areas. As discussed in Exhibit 60 entitled, "Subsidence <br />Evaluation of the Apache Rocks and Box Canyon Mining Areas", the panel design was similar to <br />the current West Elk Mine longwall panels. An average of about 12 feet of coal was extracted from <br />the B -seam in both areas and an average of about 11 feet will be extracted from the E -seam in the <br />western panels of the Apache Rocks mining area. The E -seam is not planned to be mined in the <br />Box Canyon mining area. In the Apache Rocks mining area, E -seam mining is planned to occur in <br />Sections 28, 29, and 30 as presented in Exhibit 60E. Top coal and bottom coal may be left in place <br />in these areas to improve roof and floor stability. <br />As further discussed in Exhibit 60, 60A and 60E, gateroad development typically entails <br />development of three entries leaving two rows of chain pillars; one row a rigid pillar design and one <br />row a yielding pillar design. Planned panel and pillar designs in the yet unmined E -seam panels in <br />the Apache Rocks mining area are subject to change depending on geotechnical conditions and <br />actual mining experience. Panel lengths and widths will be maximized as possible. <br />South of Divide and Dry Fork Mining Areas — As presented in Exhibit 60E entitled, <br />"Subsidence Evaluation for the South of Divide and Dry Fork Mining Areas", the longwall <br />mining method is also being utilized in the South of Divide and Dry Fork mining areas. The <br />current and planned panel design is similar to the B -seam longwall panels in the Box Canyon and <br />West Flatiron lease areas. As further discussed in Exhibit 60E, a range of 8 to 14 feet of coal has <br />and will be extracted from the E -seam depending on the actual seam structure, coal quality, and <br />other operating constraints encountered. <br />As with .all mining, projected pillar and panel dimensions and extraction thicknesses are based on <br />the best available exploration data and professional judgment. The mined and projected E -seam <br />longwall panel layout is shown on Map 51, along with the maximum projected areal extent of <br />potential mining within the lease and permit boundaries. Although not anticipated, should <br />mining be extended beyond the projected longwall panel layout shown on this map, the <br />associated projected impacts of subsidence have been evaluated in Exhibits 55B & 60E. <br />Planned panel and pillar dimensions may be adjusted within the lease and permit boundaries if <br />warranted by actual mining conditions, including coal thickness, coal quality, and geotechnical to <br />fulfill federal coal lease maximum economic recovery requirements. <br />2.05-119 Rev. 06/05- PRIO, 03/06- PRIG, 05/06- PR10, 11/060- TRIO7, 04/07- TR108, 09/07- PR12, 02/08- PR12; 11110-TR124 <br />