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Subsidence Evaluation for the <br /> Exhibit 60E Southern Panels, Apache Rocks West, & Sunset Trail Mining Areas Page 28 <br /> 9.0 WATER AND METHANE <br /> Observations of the north and west flanks of Mt. Gunnison during aerial geologic mapping and an <br /> October 1996 field trip revealed numerous talus and rock glacier deposits that occur in the valleys <br /> and lower part of this intrusive body. Snowmelt and rain can easily infiltrate these deposits,which <br /> may eventually enter any permeable rocks, faults, fractures, and joints near the mountain. Coal <br /> beds and rocks in the deformed zone around Mt. Gunnison may also contain increased <br /> concentrations of methane where the coal is deformed and perhaps metamorphosed to a higher <br /> rank by the intrusive body. Greater quantities of water and methane may therefore be expected as <br /> coal is mined closer to Mt. Gunnison. <br /> 9.1 Potential Impact of Water on Subsidence in Wet Mining Areas <br /> As discussed in Section 3.0,the moisture content of the caved and downwarped rocks controls the <br /> amount of subsidence that can be expected. In the Southern Panels, Apache Rocks West, and <br /> Sunset Trail mining areas where water might be encountered in an area equal to, or greater than, <br /> the width of the proposed longwall panels, maximum vertical displacement may be expected to <br /> approach 0.8t. <br /> 831-032.912 Wright Water Engineers, Inc. <br /> December 2020 <br />