Treatment technology of roof instability in the fault fracture zone of the high mining face in weak coal seams

In response to the difficulties of surrounding rock instability, coal wall caving, and roof collapse in the treatment of near parallel transverse faults in weak coal seams with high mining height, this paper takes the 22205 working face of Yanping Coal Mine of Shanxi Huaning Coking Coal Co. Ltd. as the engineering support, systematically studies the mechanical response characteristics and dynamic instability evolution laws of coal and rock in the fault fracture zone, and proposes a collaborative treatment technology system based on “advanced cement grouting reinforcement and instant chemical grouting reinforcement”. Through multi parameter optimization and refined control of the entire process, the stability of the surrounding rock in the fault zone is significantly improved. Based on the “32345” comprehensive governance framework (three principles, two methods, three advanced management, four types of control, and five character policy), the stability of the surrounding rock in the fault zone has been significantly improved by optimizing the grouting parameters (pressure 15-30 MPa, water cement ratio 0.8) and construction process, combined with on-site testing and numerical simulation verification. The research team implemented staged infiltration filling and dynamic reinforcement on 4 large faults (YD4, YD5, YD12, and YD2 edge faults) and 13 small faults within the working face, successfully reducing the coal wall caving rate by 45% and improving the efficiency by 15%. This technology can provide theoretical support and technical reference for safe mining of weak coal seams under similar geological conditions.