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"D" Seam Longwall Subsidence Page 92 August 17, 1998 <br />• The subsidence contours plotted along the longitudinal axis of <br />Panel Group 1 on Plate 1 for each of the overburden contours were <br />based on the conservatively predicted total mid-panel ground <br />surface subsidence for each individual panel. The total mid-panel <br />vertical surface subsidence was obtained by adding the individual <br />panel vertical subsidence, the mid-panel subsidence resulting from <br />longwall mining of the adjacent panels and the vertical subsidence <br />resulting from the planned crushing of the gateroad pillars between <br />adjacent panels, following extraction of both adjacent longwall <br />panels. <br />The Panel Group 1 surface subsidence contours plotted along <br />the longitudinal axis of the of Panel Group 1 on Plate 1 were <br />obtained using the subsidence profile prediction graph in Appendix <br />B, Graph 3, plus the predicted adjacent gateroad pillar crushing <br />ground surface subsidence, tabulated on Table 7, and plus the <br />profile calculated vertical subsidence from the individual adjacent <br />longwall Panel #2 above the gateroad pillar between Panel #1 and <br />Panel #2. Table 8 presents the various Panel Group 1 components <br />and the total predicted ground surface subsidence at each of the <br />overburden depth contours. The locations of the Panel Group #1 <br />maximum tensile and compressive strains plotted on Plate #6 were <br />obtained using the horizontal strain profile prediction graph in <br />Appendix B, Graph 4 and the total predicted vertical maximum <br />mid-panel vertical subsidence. <br />Table 9 presents the vertical surface subsidence components <br />for Panel Group 2 Panels #4 - #6. Table 10 presents the vertical <br />surface subsidence components for Panel Group 3 Panels #7 - #9. <br />Table 11 presents the vertical surface subsidence components for <br />Panel Group 4 Panels #10 - #13. Table 12 presents the vertical <br />surface subsidence components for Panel Group 5 Panels #13 - #16. <br />Locations for all the predicted vertical surface subsidence <br />contour values were calculated at each position along the panel <br />group ribsides where a depth contour crossed and the predicted <br />subsidence contours and at the midpoint along each panels final <br />recovery room and starter room, using the NCB subsidence profiling <br />Graph 3 in Appendix B. The vertical subsidence contours are <br />1-foot, 2-foot, 4-foot, 6-foot, 8-foot, 10-foot, 12-foot and <br />14-foot. The vertical surface subsidence contours are plotted on <br />Plates 1 through 5. <br />The maximum tensile and compressive horizontal surface strain <br />lines were calculated at each of the panel group subsidence <br />profiling locations, using the NCB horizontal strain profiling <br />Graph 4 in Appendix B. The maximum horizontal tensile strain line <br />is the most important because it represents a prediction of the <br />location of ground surface fractures associated with the downward <br />• <br />az <br />