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"D" Seam Longwall Subsidence Page 62 August 17, 1998 <br />ail ~~. 2 <br />Ate. GRAPHS USED TO PREDICT SUBSIDENCE EFFECTS <br />• 1) Vertical subsidence correction graph for longwall panel width <br />with respect to depth (NCB, 1975) <br />2) Maximum extension (+E) and compression (-E) multipliers for <br />panel corrected maximum vertical subsidence divided by panel <br />depth for the specific panel width/panel depth conditions <br />3) Subsidence profile construction graph for panel specific <br />width/height ratio, distance from panel centerline in terms of <br />depth and proportion of maximum predicted vertical subsidence <br />and at that distance from the panel centerline <br />4) Horizontal ground surface tensile and compressive strain <br />profile construction graph for panel specific width/height <br />ratio, distance from panel centerline in terms of depth and <br />proportion of maximum predicted horizontal tensile (positive <br />values) compressive (Negative values) and at that distance from <br />the panel centerline <br />• <br />• <br />62 <br />