Mining subsidence prediction for multi-seam and non-rectangular goafs based on probability integral model: a case study from China

Ground subsidence associated with underground mining has caused environmental and economic damage in coal mining areas. So it is important to predict mining subsidence prior to any coal extraction. In order to predict mining subsidence based on probability integral model, we present a triangle subsection method for mining subsidence calculation of non-rectangular goafs. In the probability integral model, multi-seam subsidence is determined by using cumulative subsidence coefficients for different coal seams that reflect the amount of mining in a given region and by adding up the subsidence for every single coal seam in the research area. In the triangle subsection method, non-rectangular goafs are divided into several triangular areas rather than approximately rectangular areas, which can avoid errors resulting from the latter approximation method. The proposed method is then used to compare with rectangular subsection method to predict the subsidence induced by multi-seam non-rectangular goafs within a coal mine in the Liu Fangzi area of China as a case study. From the comparison, results show that the proposed approach can effectively deal with subsidence prediction related to non-rectangular goafs.