Mechanism of coal bump induced by joint slipping under static and dynamic stresses in graben structural area.

Deep coal mining activities close to a fault generally cause shear stress concentration and slipping of the fault. This increases the risk of coal bumps and severely endangers miners' lives as well as the effectiveness and productivity of mines. In this study, seismicity distribution resulting from fault slipping induced by mining in the graben structural area and the coal bump seismic precursors are investigated using high-precision seismic monitoring technology. Subsequently, the evolution of stresses in rock masses and fault reactivation characteristics during the mining process is analysed via numerical simulation. With the advancement of the working face, the maximum principal stress difference between the two sides of the fault gradually increases, resulting in shear slipping of the fault (i.e., fault reactivation). Seismicities occur frequently because of the repeated release of accumulated elastic energy. The number and total energy of mining-induced seismicities in the hanging wall of the fault are higher than those in the footwall. The frequency and number of mining-induced seismicities decrease before the occurrence of the coal bump. Additionally, the mechanism of the coal bump induced by fault slipping, caused by the superposition of static and dynamic stresses during coal mining, is investigated. [ABSTRACT FROM AUTHOR]