3D Numerical Study of Underground Coal Mining Induced Strata Deformation and Subsequent Permeability Change

Proper understanding of mining induced change in permeability in overburden strata during advancement of longwall faces is essential to estimate the groundwater flow on the overburden strata, in order to assist with the assessment of water inrush potential and impact of mining on ground and surface water system. In this study, numerical modelling approach has been used to investigate the change in permeability on the overburden strata due to the underground extraction. The results show that the permeability immediately above the mining seam increases in excess of six orders of magnitude. Depending on the sequence of mining, either side of the longwall could have different fracturing patterns resulting in different magnitude of permeability change. A well-defined permeability curve can provide quantitative estimation of various distinct regions of change in permeability.