Mine subsidence as a post-mining effect in the upper Silesia coal basin

On the basis of three selected examples, some problems attributed to the presence of voids resulted from mining operations in already commissioned underground coal mines are discussed. Continuous and discontinuous deformations of the ground surface (sinkholes and subsidence troughs) of anthropogenic origination implicate hazards for the ground surface, even many decades after completion of mining work. Nowadays, when decommissioning and flooding of numerous mines happens, ground movements as well as seismic events related to flooding of abandoned underground mines can be observed. The first case study draws attention to the problems of effective voids localisation methods as well as the reliability of grout injection operations for road construction purposes. The second case emphasizes a problem occurring often in areas with long and complex mining histories, meaning appropriate determination of origin, process and protective measures regarding occurred ground deformations, or damage to buildings. The third case describes specific effects on the surface (shocks and ground surface elevation) generated by the flooding of decommissioned mines.