Laserfiche WebLink
Figure 22 <br /> Subsidence Calculations , Control Point TP-1 and Longwall 102 <br /> Point TP-1 is near the center of longwall panel 101, No. 1 mine, <br /> extracted mid-1978. TP-1 was not surveyed between installation <br /> in 1981 and 9/17-20/84, when 0.97 ft of subsidence was noted. Long- <br /> wall panel 102 was begun in late 1983. Calculations assume point <br /> was stable and that all movement is due to 102 mining. <br /> Distance from 102 tailgate to TP-1 (x) : 375 ft. <br /> Surface elevation TP-1: 11,845 ft. <br /> Coal elevation at tailgate: 9,012 ft. <br /> Surface elevation over tailgate: 11,820 ft. <br /> Depth to coal (H) : 2,808 ft. <br /> x TP-1 <br /> yLwalls <br /> Hno scale <br /> • longwall 101 <br /> longwall 102 A bed <br /> Slope angle 1 <br /> � = tan X <br /> = tan-1 25 <br /> 375 <br /> = 3.810 <br /> Apparent angle of draw to TP-1 (A) : <br /> A = tan-1 x <br /> Hcos20 <br /> = tan-1 375 <br /> 2808cos23.81 <br /> = tan-1 375 <br /> 2808 1.00 <br /> = tan-1(0.13) <br /> = 7.640 <br /> • <br />