Rockburst risk identification and mitigation in coal mining under mountainous terrain: A case study from the Tianshan region

Rockburst poses a severe threat to underground coal mining in mountainous terrain, yet its specific mechanism under variable topographic loads remains inadequately studied. Focusing on the Kuangou Coal Mine beneath the rugged topography of the Tianshan Mountains, this work integrates theoretical analysis with multi-source field monitoring to investigate terrain-induced rockburst risk and its mitigation. Results provide field evidence suggesting that mining under high-relief mountains concentrates high-energy seismic events and extreme support pressures. These phenomena are closely associated with rockburst occurrence, which can be explained by the coupling of static compressive stress and dynamic rotating stress. A novel risk identification method is developed using a membership function that synthesizes topographic factors: mountain height, gully drop, gully width, and slope angle. Applied to the I010206 working face, the method identified five additional high-risk zones overlooked by conventional methods, three of which were validated by actual mining. Directional long-borehole hydraulic fracturing was subsequently implemented for rockburst mitigation. After fracturing, microseismic frequency increased by 32.8%, while total energy decreased by 53%, with no events exceeding 104 J. Microseismic activity shifted from “high-energy, low-frequency” to “low-energy, high-frequency”, indicating more stable energy release and reduced rockburst risk. This study provides a practical framework for managing rockburst risk in mountain mining areas.