Mining-induced subsidence prediction by displacement discontinuity method

Abstract

It is essential to predict the mining-induced subsidence for sustainable mine management. The maximum observed subsidence having a noticeable areal extent due to Northern Upper Panels (NUP) and Southern Lower Panels (SLP) at the Barapukuria longwall coal mine is 5.8 m and 4.2 m, respectively, after the extraction of a 10 m thick coal seam. The mining-induced subsidence was simulated by the Displacement Discontinuity Method (DDM). The numerical model considered the effects of the ground surface, mining panels, faults, and the dyke. The predicted and the observed subsidence due to the mining of NUP and SLP were compared varying Young's modulus, and the 0.10 GPa Young's modulus was found to be the best match. The effects of the faults and the dyke in the calculation were found to be negligible. Future subsidence was predicted by considering 30 m extraction of the thick coal seam as 15.7 – 17.5 m in NUP and 8.7 – 10.5 m in SLP. For proper/sustainable mine management, the mining authority might need to count on this subsidence issue.