Coal–Rock Dynamic Disaster Prevention Mechanism Based on the Dual Loads of Dynamic Barrier and Static Pressure Relief by Hydraulic Slotting

According to the characteristics of coal-rock dynamic disasters and hydraulic slotting, the mechanism of dynamic load barrier and static load pressure relief in hydraulic slotting is proposed. The stress distribution in a coal mining face and the slotted area of a section coal pillar is analyzed by numerical simulation. The results show that the slot formed by hydraulic slotting can effectively alleviate the stress concentration and transfer the high-stress area to a deeper coal seam. When slotting and blocking the dynamic load propagation path in a coal seam, the wave intensity of the stress wave transmitted into the slot is greatly reduced, so the risk of a coal-rock dynamic disaster is reduced. A field application of hydraulic slotting prevention technology was carried out in the Hujiahe coal mine. An investigation of microseismic events and an evaluation of the rock noise system show that the average event energy within 100 m mining mileage decreased by 18%, the microseismic energy per unit footage decreased by 37%, the times of strong mine pressure behavior evaluated in the working face decreased by 17%, and the number of risks decreased by 89%. In conclusion, hydraulic slotting technology can effectively reduce the risk of coal-rock dynamic disasters in mining faces and provides a more effective technical means for coal-rock dynamic disaster prevention.