The influence of selected mining and natural factors on the sinkhole creation hazard based on the case study

The formation of sinkholes, especially in developed areas, constitutes a considerable hazard to the public safety. Due to the above, the subject of the paper is a significant and current issue. The paper includes a case study of sinkholes forming over shallow mine galleries. Calculations of the workings’ stability and the impact of the underground mining exploitation have been conducted. The probability of sinkhole formation has been determined as well. The time of sinkholes formation did not correspond with the time in which the mining exploitation affected the gallery workings and the moment in time for which the rock mass deformations caused by the exploitation were at the highest level. The performed exploitation caused occurrence of cracks in the rock mass over the working. This allowed the transportation of the loose overburden by rainwater to workings and as a result sinkholes were created—suffosion occurred. The Quaternary overburden built of sands and sandy loams was probably washed out by rainwater, which led to the formation of sinkholes. In all locations, where shallow voids exist at a depth up to 100 m and the overburden consists of loose rocks, one should consider the probability of sinkholes formation.