Numerical Simulation Analysis for the Selection of Suitable Mining Method in Consideration of the Surface Subsidence and the Safety of Stop and the Mining Recovery Rate

Abstract

Selecting a suitable mining method, considering surface subsidence, stope safety, and mining recovery rate under the mining and geological conditions of the object, is very important for safe mining, protection of surface structures, and minimizing coal loss. In this paper, we numerically investigated the suitable mining method in consideration of the surface subsidence and the safety of stope and the mining recovery rate by using FLAC3D and SURPAC software with a change of stope pillar size in case of mining a thick coal seam with a dip of 30° by using the different room and pillar methods at a depth 97m from surface. First, we construct a 3D block model using SURPAC software. Then, we convert the SURPAC 3D block model into a FLAC3D 3D block model and analyze stope safety, surface subsidence, and mining recovery rate. As a result of the analysis, we proved that the stope safety is ensured. The maximum surface subsidence is about 2.2cm in the strike and dip directions, respectively. The mining recovery rate is about 86% under stope pillar sizes of 2m and stope pillar spacing of 4m. We presented the analysis results from the Gae Chon coal mine and demonstrated their reliability.