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Subsidence Evaluation for the <br /> Exhibit 60E Southern Panels, Apache Rocks West, & Sunset Trail Mining Areas Page 14 <br /> to 0.8t)where the extraction thickness is 14 feet. This estimate is only for the areas <br /> over panels E2 to E5 and B26 to B29. <br /> Apache Rocks West Mining Area: Overburden depth above the projected E-seam longwall centers <br /> ranges from 400 to 1,100 feet. With a projected longwall panel width of approximately 1,080 feet, <br /> maximum subsidence (vertical displacement S. = a • t) is predicted as follows (Table 3) for the <br /> Apache Rocks West mining area of panels E10 to E12: <br /> • Panels EIO to E12: These panels range in width from subcritical to supercritical (width-to <br /> depth ratio (W/d) ranges from 0.98 to 2.70). <br /> 1. Maximum vertical displacement above the chain pillars (s,,P) is expected to range <br /> from 1.0 to 4.0 feet (0.1 to 0.3t) where the extraction thickness is 10 feet, and 1.4 <br /> to 5.6 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 6.0 to 8.0 feet (0.6 to 0.8t) where the extraction <br /> thickness is 10 feet, and from 8.4 to 11.2 feet where the extraction thickness is 14 <br /> feet. <br /> Overburden depth above the B-seam longwall centers ranges from approximately 750 to 1,300 <br /> feet. With a longwall panel width of 950 feet, maximum subsidence (vertical displacement Sm=a <br /> • t) is predicted as follows (Table 3) for the Apache Rocks West mining area of panels B 12 to <br /> B 13A: <br /> • Panels B12 to B13A: These panels range in width from subcritical to supercritical (width- <br /> to depth ratio (W/d)ranges from 0.73 to 1.27). <br /> 1. Maximum vertical displacement above the chain pillars (Scp) is expected to range <br /> from 1.2 to 4.8 feet(0.1 to 0.3t) where the extraction thickness is 12 feet. <br /> 2. Maximum vertical displacement above the mined longwall panels(subsidence, Sm <br /> a • t) is projected to range from 7.2 to 9.6 feet (0.6 to 0.8t) where the extraction <br /> thickness is 12 feet. <br /> The E-seam panels E10 to E12 and B-seam panels B12 to B13-A occur on top of one another,but <br /> are not stacked based on the current panel layout (Figure 1). However, to be conservative, the <br /> maximum subsidence(vertical displacement Sm=a•t)of the two seams is assumed to be additive. <br /> 3. Maximum vertical displacement above the chain pillars (Scp) due to both E-seam <br /> and B-seam mining cannot be estimated, as the chain pillars for the E-seam and B- <br /> seam are not located on top of one another. <br /> 4. 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 13.2 to 17.6 feet <br /> (0.6 to 0.8t)where the E-seam extraction thickness is 10 feet, and from 15.6 to 20.8 <br /> feet (0.6 to 0.8t) where the E-seam extraction thickness is 14 feet. This estimate is <br /> only for the areas over panels E 10 to E-12 and B 12 to B 13-A. Due to the offset <br /> 831-032.912 Wright Water Engineers, Inc. <br /> December 2020 <br />