A New Method to Assess Coal Burst Risks Using Dynamic and Static Loading Analysis

Abstract

Mining-induced seismicity is one of the dynamic energy sources that can trigger coal burst. This paper presents a new methodology to assess coal burst risks under different loading conditions by examining seismic energy attenuation and fracture size. Two new indices are proposed: (1) Dynamic Load Index (DLI) quantifies the magnitude of dynamic loading induced by seismic events, based on the relationships between the seismic energy, peak particle velocity and dynamic stress; (2) dynamic–static loading assessment index, $$I_{\text{PD}}$$, links the DLI with passive velocity tomography (PVT) to assess the coal burst risks in a longwall panel under dynamic and static loading. A total of 3080 seismic records were examined to validate $$I_{\text{PD}}$$ in a typical burst-prone longwall panel in China. Based on the rate of occurrence of high-magnitude seismic events, $$I_{\text{PD}}$$ thresholds were determined to identify low-, medium- and high-risk coal burst zones. Using this new zoning approach, coal burst risks were assessed in the same longwall panel while mining through a fault structure. The proposed risk classes correlated well with the recorded high-magnitude seismic events with energies over 10 kJ. The analysis indicated that 69% of the high-magnitude events occurred in the high-risk zones, where $$I_{\text{PD}}$$ was between 0.35 and 1; and 31% of the events occurred in the medium-risk zones, where $$I_{\text{PD}}$$ was between 0.2 and 0.35.