Analysis of Surface Subsidence and Relative Movements of Underground Rock Strata over an Inclined Longwall Panel

Abstract

Subsidence monitoring and analysis is an integral part of longwall operation. It provides an assessment of the effect of mining on the surface. In this study, subsidence data is recorded periodically over a longwall panel of 250m of face length and 2333m of gate roadway length for a duration of 12 months. The working seam is inclined at 10 degrees (1 in 5.5) towards tailgate side. Based on the measured data, a profile function is derived indicating vertical ground movement over the major section of the longwall panel. The bed separation of layers in the roof rock is also measured by installing Multi-Point Borehole Extensometer (MPBX) at the centre of the longwall panel and its results are correlated with those of subsidence monitored data. It is found from the analysis of subsidence and MPBX data that there is a good correlation between the bed separation sequence and the subsidence over longwall panel.