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West Elk Mine: Subsidence Evaluation ojthe Revised Mine Pane! <br />Layouts in Section 2! and Sections 26 and 27 Pa Pe 4 <br />• primarily a function of the rotation of the panels allowing most of the fourth panel to fall <br />within the permit area. <br />Even with the rotated panels, the profiles of the vertical displacement (Figure 5) for the <br />two panel configurations aze very similar. The maximum subsidence is predicted to be <br />slightly larger (7.3 feet versus 7.1 feet) for the revised panel layout due to Panel 2 having <br />a smaller overburden cover. The subsidence over the chain pillazs is expected to be <br />reduced under the revised panel layout due to larger chain pillars. The maximum <br />subsidence over the chain pillazs will likely decrease from 4.2 feet with the original <br />layout to 4.0 feet with the revised layout. The differences in these parameters are <br />extremely minor. <br />As with the Section 21 panels, the lift and strain profiles (Figures 6 and 7, respectively) <br />reflect values in the same range for both the original and revised panel layouts. The <br />maximum values of these parameters aze predicted to be approximately equal for both <br />• layouts. <br />REVIEW OF SUBSIDENCE EFFECTS CAUSED BY REVISED <br />PANEL CONFIGURATIONS By C. Richard Dunrud, P.E. <br />I have reviewed and checked the results of the computer model studies by Wright Water <br />Engineers for the revised longwall panels in Section 21 and Sections 26 and 27, T 13 S, R <br />90 W, 6 PM. The following mining and subsidence pazameters were evaluated in their <br />original and revised panel layouts: <br />I. Mining Parameters in Section 11 and Sections 16 and 17. All original and <br />revised longwall mining panel widths and lengths and average overburden <br />thickness values in their original and revised panel configurations were reviewed <br />and checked for accuracy as input values to the model analyses. <br />• II. Subsidence Parameters in Section 11 and Sections 26 and 27. The following <br />subsidence parameters were checked in the computer model resulu for both the <br />Wnghi -vafer EngiKerr, lnc. 83/-03I. 50 <br />