Influence of Mining Parameters on Stress and Fissure in Long Distance Upward Pressure Relief Mining

Based on the mining geological conditions of A₃ coal and B₄ coal in Pan’er Coal Mine, a numerical simulation model of long-distance upward pressure relief mining of A₃ coal was established. By changing the mining parameters of the model, the influence law of mining thickness and face length on stress field and displacement field distribution in long-distance upward pressure relief mining is obtained. The results show that the mining thickness of the lower relief seam is the fundamental factor affecting the movement and failure of the overlying strata and the height of fracture development. With the increase of mining thickness, the development height of caving zone and fracture zone increases, and the pressure relief range enlarges accordingly; the mining face length has a great influence on the pressure relief range of upward pressure relief mining, and to a certain extent, the face length determines whether the coal seam is fully mined or not, and the pressure relief range of the pressure relief bed under the condition of full mining is larger than that under insufficient mining condition.