A coal seam-roof-floor coupling destressing control method of fault coal bursts induced by deep coal seam mining

Fault coal bursts is a common type of coal bursts in coal mining. With increases in mining depths and mining intensities, the occurrence frequency and disaster degree of coal bursts in fault-controlled areas are increasing in severity. Therefore, in this article, the mechanism and control method of deep mining-induced fault coal bursts are analysed on the No. 3402 longwall panel controlled by two faults in the Shandong Mine, China. Based on the microseismic monitoring data of the longwall panel, the fault activation process induced by mining can be divided into four stages. The second energy release and fault activation stages are risk stages of fault coal bursts. Using numerical simulation, the evolution laws of vertical stress, elastic strain energy in front of the longwall panel, and the ratio of shear stress to normal stress on fault plane are investigated. The phenomenon of a 'high elastic energy section-low elastic energy section' coal pillar between faults is revealed, and the mechanism of coal pillar coal bursts induced by high elastic energy is discussed. Third, based on the above research results, coal burts risk areas of the longwall panel in the fault-controlled area are determined. The method of 'coal seam-roof-floor coupling destressing with the reduction in mining speed' to control fault coal bursts is introduced. Field test results show that the method effectively destroys the integrity and bearing capacity of the coal seam, significantly reduces the energy storage capacity of the superposition area of mining stress and fault tectonic stress, so that the coal bursts risk of the coal seam in the fault control area is relieved, ensuring safe and efficient mining of the longwall panel. The method can provide a reference for other coal mines with similar geological conditions.