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Subsidence Evaluation for the <br /> Exhibit 60E Southern Panels, Apache Rocks West, & Sunset Trail Mining Areas Page 13 <br /> 1. Maximum vertical displacement above the chain pillars (Scp) is expected to range <br /> from 0.9 to 2.7 feet (0.1 to 0.3t) where the extraction thickness is 9 feet, and from <br /> 1.4 to 4.2 feet (0.1 to 0.3t)where the extraction thickness is 14 feet. <br /> 2. Maximum vertical displacement above the mined longwall panels(subsidence, Sm <br /> a • t) is projected to range from 5.4 to 7.2 feet (0.6 to 0.8t) where the extraction <br /> thickness is 9 feet, and from 8.4 to 11.2 feet (0.6 to 0.8t) where the extraction <br /> thickness is 14 feet. <br /> Overburden depth above the projected B-seam longwall centers ranges from approximately 600 to <br /> 1,500 feet. With a projected longwall panel width of approximately 1,080 feet, maximum <br /> subsidence (vertical displacement Sm = a • t) is predicted as follows (Table 2) for the Southern <br /> Panels mining area of panels B26 to B29: <br /> • Panels B26 to B29: These longwall panels range in width from subcritical to supercritical <br /> (width-to depth ratio (W/d) ranges from 0.72 to 1.80). <br /> 1. Maximum vertical displacement above the chain pillars (Scp) is expected to range <br /> from 0.9 to 2.7 feet (0.1 to 0.3t) where the extraction thickness is 9 feet, and from <br /> 1.4 to 4.2 feet(0.1 to 0.3t)where the extraction thickness is 14 feet. <br /> 2. Maximum vertical displacement above the mined longwall panels(subsidence, Sm <br /> a • t) is projected to range from 5.4 to 7.2 feet (0.6 to 0.8t) where the extraction <br /> thickness is 9 feet, and from 8.4 to 11.2 feet (0.6 to 0.8t) where the extraction <br /> thickness is 14 feet. <br /> The E-seam panels E1 to E5 and B-seam panels B26 to B29 occur on top of one another, but are <br /> not stacked based on the current panel layout(Figure 1). Therefore,while the subsidence(vertical <br /> displacement Sm = a • t) of the two seams is additive, the maximum subsidence due to mining in <br /> each seam will not occur at the same location. The closer the alignment of the B-seam panel occurs <br /> in a stacked manner relative to the E-seam panels,the more additive the maximum subsidence will <br /> be. <br /> The superposition of the subsidence curves for the longwall mining of the E-seam and B-seam <br /> indicates that the combined maximum subsidence will be roughly 80 percent of the sum of the <br /> maximums for each seam. To be conservative, the maximum for the two-seam mining will be <br /> estimated by summation of the maximums for each seam. <br /> 1. Maximum vertical displacement above the chain pillars (Scp) due to both E-seam <br /> and B-seam mining is conservatively estimated to be the summation of the <br /> subsidence for each seam,as the chain pillars for the E-seam and B-seam are nearly <br /> located on top of one another. For the two seam panel area, the maximum vertical <br /> displacement is estimated to range from 2.8 to 8.4 feet (0.1 to 0.3t) where the <br /> extraction thickness is 14 feet. <br /> 2. Maximum vertical displacement above the mined longwall panels(subsidence, Sm <br /> a•t)for the B-seam and E-seam mining is projected to range from 10.8 to 14.4 feet <br /> (0.6 to 0.8t)where the extraction thickness is 9 feet, and from 16.8 to 22.4 feet(0.6 <br /> 831-032.912 Wright Water Engineers, Inc. <br /> December 2020 <br />