Influence of mining depth and panel length in longwall underground coal mining on the distribution of principal stresses along the barrier pillars

Abstract The production increase in longwall underground coal mining is in line with the dimension changes of the mining panel that subsequently affect changes in stress distribution and disrupts roadway stability. This paper studies the effect of panel dimensions on stress distribution around the roadway using the finite element method to model the panel conditions numerically, drawing height and shape of the goaf from empirical data. In this study, the length of the panels made varied between 500 and 1500 meters and the depth of the panels varied between 200 and 1000 meters from the surface. Based on the modelling results, stress changes due to differences in panel size occurred at the depth of 800 and 1000 meters, the longer the panel, the greater the stress that occurs. The further from the surface, the greater the pressure on the barrier pillar, at a depth of 200 meters the main pressure is 3.4 times the vertical pressure at the end of the excavation, while at a depth of 1000 meters the pressure increases to 5 times the vertical pressure.