Control practice of thick and hard roof based on deep-hole pre-splitting blasting

In view of problem of strong mine pressure on working face with thick and hard roof, taking 11313 working face of Panbei Mine as engineering background, based on theoretical analysis of breakage characteristics of main roof, deep-hole pre-splitting blasting scheme of thick and hard main roof was formulated, and stress evolution law of surrounding rock under different thickness of deep-hole pre-splitting blasting and distribution of advancing abutment pressure under effective thickness of deep-hole pre-splitting blasting were studied by numerical simulation. The simulation results show that stress arch rotates to the side of transport roadway, stress arch height increases with the increase of blasting thickness and stress arch shape changed from spoon to ellipse. When thickness of main roof pre-splitting blasting is 12 m, influence range of advancing abutment pressure and distance between peak abutment pressure and coal wall of the working face increase by 8.5 m and 18.8 m respectively compared with that before the blasting, and advancing abutment pressure concentration coefficient decrease from 1.67 before blasting to 1.3 after blasting. The field monitoring results show that after the pre-splitting blasting of thick and hard main roof, the maximum load and average load of support in lower of working face decrease, dynamic load coefficient of support fluctuates significantly, and rib spalling of coal wall is effectively controlled.