Laserfiche WebLink
0 P <br /> 0.2 <br /> 0.4 0 <br /> S/S. o <br /> NCB, 1975 o <br /> -1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 <br /> X/d <br /> Figure 11. Subsidence development curves relative to a point (P) from the 5NW longwall panel <br /> at the West Elk Mine (squares), and Somerset room-and-pillar (circles, subsidence more than 90 <br /> percent complete and triangles, subsidence only 60 percent complete) as compared to the average <br /> National Coal Board curve (1975). This relationship is shown as the ratio of subsidence to <br /> maximum subsidence (S/Sm)versus the ratio of face position to overburden depth (X/d). <br />