Frictional Instability and Dynamic Slip in Deep Coal–Rock Systems: Mechanisms and Engineering Implications

Rapid slip along discontinuities in deep coal–rock systems releases stored energy and generates transient loading that may trigger coal bursts. This review compares intra-coal, coal–rock interface, and fault-zone slip using evidence from laboratory experiments, physical models, numerical simulations, and field observations. The comparison accounts for scale, boundary conditions, parameter calibration, and field validation. The Mohr–Coulomb criterion identifies the onset of shear failure but not the transition to unstable slip, which depends on post-peak weakening, rate dependence, contact history, and loading-system stiffness. Hazard attribution cannot rely on source energy alone. Fracture energy and frictional dissipation occur at the source, whereas only part of the radiated energy reaches a roadway after attenuation and scattering. Microseismic activity near a fault does not establish fault slip without independent evidence from a compatible source mechanism, fault displacement, or stress change. The source–path–roadway framework distinguishes source-region destressing, propagation-path modification, and roadway protection. Parameter transfer among specimen, model, and mine scales remains poorly calibrated. Most mine-scale evidence is drawn from Chinese coal mines. Prospective tests across multiple mines are needed to determine whether measurable friction and energy parameters can improve field warning and control.