Mechanism and Prevention Practice of Coal Burst in Deep Gradual Residual Coal Pillar Area: A Case Study

This study aimed to study the mechanism of coal burst through theoretical analysis, numerical simulation, and field practice because of the frequent occurrence of strong mining tremor events during mining in the deep gradual residual coal pillar (GRCP) area of a Chinese Coal Mine. The study established the stress model of the residual coal pillar area, theoretically calculated the stress distribution characteristics of the coal pillar area before and after mining, and determined three stress concentration areas in the coal pillar area. The stress concentration degree was as follows: area ③ > area ② > area ①. The simulation results showed that during the mining of working face, the stress concentration range of the gradual residual coal pillar area further expanded, the stress concentration coefficient increased by 23.8%–38.9%, the stress peak shifted to the goaf side, the stress in the residual coal pillar area presented a “platform” distribution, and a “high-stress residual coal pillar” was formed in the coal pillar area. The prevention scheme of directional blasting load reduction of roadway roof and coal seam in the coal pillar was formulated based on the stress distribution characteristics and coal burst mechanism in the area of gradual residual coal pillar. The prevention and control scheme effectively reduced the stress level of coal strata in the coal pillar area and avoided the occurrence of coal burst in the high-stress area of gradual residual coal pillar, providing reference and guidance for the prevention and control of coal burst at the working face under similar conditions.