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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 950 feet, maximum <br />subsidence (vertical displacement Sm = a - t) is predicted as follows (Table 3) for the Apache Rocks <br />West mining area of panels E10 to E12: <br />- Panels EIO to E12: These panels range in width from subcritical to supercritical (width -to depth <br />ratio (W/d) ranges from 0.86 to 2.38). <br />1. Maximum vertical displacement above the chain pillars (sop) is expected to range from 1.0 <br />to 4.0 feet (0.1 to 0.3t) where the extraction thickness is 10 feet, and 1.4 to 5.6 feet (0.1 to <br />0.3t), where the extraction thickness is 14 feet. <br />2. Maximum vertical displacement above the mined longwall panels (subsidence, Sm = a - t) <br />is projected to range from 6.0 to 8.0 feet (0.6 to 0.8t) where the extraction thickness is 10 <br />feet, and from 8.4 to 11.2 feet where the extraction thickness is 14 feet. <br />Overburden depth above the B -seam longwall centers ranges from 750 to 1,300 feet. With a <br />longwall panel width of 950 feet, maximum subsidence (vertical displacement Sm = a - t) is <br />predicted as follows (Table 3) for the Apache Rocks West mining area of panels B26 to B29: <br />• Panels B26 to B29: 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 E 10 to E 12 and B -seam panels B 12 to B 13-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 (Sp) due to both E -seam <br />and B -seam mining cannot be estimated, as the chain pillars for the E -seam and 13 - <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 1310 to E-12 and B12 to 1313-A. Due to the offset <br />alignment of the E -seam panels from the B -seam panels, the maximum subsidence <br />831-032.816 Wright Water Engineers, Inc. <br />October 2018 <br />