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West Elk Mine <br />• areas are fracture controlled, it is extremely unlikely that they extend downward to the E Seam <br />through multiple shale and siltstone units. Using this conservative evaluation, it is now important to <br />evaluate the potential impact that subsidence may have on any pre-mining fractures. <br />Evaluation of subsidence due to downwarping of laterally-constrained strata shows that rock strata <br />with different deformation and strength characteristics deform as discrete units. For example, strata <br />of shale and siltstone behave as units discrete from sandstone. Above the fractured zone and within <br />the continuous deformation zone these units undergo continuous flexure (Figure 2, enlargement 2 of <br />Exhibits 60B and 60E). Above the neutral surfaces, in zones of convex-upward curvature, the <br />material is in tension and below them, the material is in compression. <br />Consequently, stresses change across neutral surfaces from tension to compression with each <br />successive rock unit that deforms as a plate. Fractures already present would thus tend to open <br />more in the zones of tension and close more in the zones of compression, which would close these <br />fractures more than they were prior to mining and subsidence. <br />After longwall mining is completed in the area and static conditions are attained, the zones of <br />tension and compression commonly cease, and any fractures present will likely resume the pre- <br />mining condition. Therefore, the impacts on surface flow in the drainage of the South of Divide <br />mining revision area are likely to be minimal or non-existent under even the most conservative <br />assumptions. <br />Water and Methane <br />• Observations of the north and west flanks of Mt. Gunnison during an October 1996 field trip, <br />revealed numerous talus and rock glacier deposits that occur in the valleys and lower part of this <br />intrusive body. Snow melt and rain can easily infiltrate these deposits, which may eventually enter <br />any permeable rocks, faults, fractures, and joints near the mountain. Coal beds and rocks in the <br />deformed zone around Mt. Gunnison might also contain increased methane where the coal is <br />metamorphosed to a higher rank by the intrusive body. Great quantities of water and methane may <br />therefore be expected as coal is mined closer to Mt. Gunnison. <br />Water and Methane in the Oliver No. 2 Mine <br />Because large quantities of water and methane were encountered while mining the E/DO Seam in <br />the Oliver No. 2 Mine, other sources may also be present in the Box Canyon mining area. In the <br />report on the closure of the Oliver No. 2 Mine, large volumes of water and methane began to flow <br />from fractures in the floor of the southernmost (top) entry of 6th East. The mine was evacuated and <br />closed because the water and methane flowed in quantities too costly to control. This area where <br />the large outpouring of Seater and methane occurred is located about 300 feet south of entries of the <br />South Mains that were not driven further, apparently because of roof control problems. <br />Water and methane intrusions were also common at least three years before the mine closure. Iii a <br />letter to the Director of the Bureau of Land Management (BLMI on January 25, 195111 :president <br />of Calumet Fuel Company described the following conditions in the Oliver No. 2 Mine <br />(unpublished letter written to BLM Director Marion Clawson by Claude P. Heiner, January 25, <br />• 1950): <br />2.05-141 Revised Ju»e 2005 PRIG. Rev. march 3006; R1ay 2006 PRIG, Alov. 2006TR107.Ap7-i1 2007TR108;Sep. 2007 PR12; Feb. 2008 PR-72