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Subsidence Evaluation for the <br />Exhibit 60E Southern Panels, Apache Rocks West & Sunset Trail Mining Areas Page 3 <br />2.0 MINING METHOD <br />The longwall mining method has and will continue to be utilized in the Southern Panels, Apache <br />Rocks West, and Sunset Trail mining areas. The E -seam longwall panel design is similar to the <br />B -seam longwall panels mined to date in the West Elk Mine, where subsidence measurements <br />were used to obtain the baseline data that were used in this report. A range of 8 to 141 feet of coal <br />will be extracted from the E -seam in the Southern Panel mining area. The four longwall panels in <br />the Sunset Trail mining area (SS1 through SS4) are proposed to have an extraction thickness <br />ranging from 9 to 14 feet. The extraction thicknesses are projected based on exploration drillhole <br />data; actual thicknesses may vary depending on mining conditions encountered. <br />E -seam longwall panels El to E8 are 1,080 feet wide and extend up to approximately 15,000 feet <br />in length. Panel E9 is projected to be 1,080 feet wide and approximately 3,200 feet long. Panel <br />E14 is projected to be 1,080 feet wide and approximately 3,300 feet long. The panels will be <br />mined by the retreat longwall mining method. Panels El to E8 and E14 are longwall mined from <br />east to west. Panel E9 is planned to be longwall mined from south to north. <br />The trend of panels El to E8 is approximately N80°W. Panel E9 trends roughly N10°E and E14 <br />trends approximately N600W. The overburden depth above the panels E1 to E4 ranges from <br />roughly 375 to 1,800 feet, whereas, the overburden depth for panels E5 to E8 ranges from 500 to <br />1,800 feet. The overburden above panel E9 and E14 ranges in thickness from 500 to 600 feet. <br />B -seam mining in the Southern Panels mining area will occur in panels B26 to B29, and will follow <br />the same orientation as the overlying E -seam panels. The panels are projected to be 1,080 feet <br />wide with lengths varying from 11,500 feet up to 14,800 feet, and mining thickness from 9 feet up <br />to 14 feet. <br />In the original Exhibit 60 (May 1995), MCC anticipated two -seam mining in the B- and E -seam <br />in the Apache Rocks West mining area. MCC has already mined the B -seam in this area (1312, <br />B13, and B13 -A); however, the layout of the E -seam panels (E10 to E12) has shifted from being <br />stacked over the B -seam panel to being offset. Panels El to E12 are projected to be 950 to 1,080 <br />feet wide and vary in length from approximately 3,800 feet to 5,300 feet. The mining thickness is <br />anticipated to vary from 10 to 14 feet. <br />E -seam mining in the Sunset Trail mining area will occur in Panels SS 1 to SS4 as shown in Figure <br />1. Panels SSI to SS4 are projected to be 1,080 feet wide with maximum lengths ranging from <br />approximately 7,200 feet up to 9,400 feet. The panels will be oriented parallel to panels E1 to E8. <br />All longwall panels are planned to be separated by two or three rows of chain pillars. The pillars <br />on both the headgate and tailgate sides of the panels are typically on centers of about 125 feet wide <br />by 200 feet long. The headgate for the adjacent panel becomes the tailgate panel on the subsequent <br />' Practically speaking, the maximum mining height with the current longwall is 13.5 feet; however, WWE is using <br />14 feet in our analysis to be conservative, except with the computer modeling. <br />2 All of the panels discussed in this exhibit are 1,080 feet wide. When evaluating subsidence, a total extraction <br />width of 1,120 feet is used to include the entries parallel and adjacent to the panel. <br />831-032.816 Wright Water Engineers, Inc. <br />October 2018 <br />