Abstract: According to the high mining stress and seismic hazard risk in excavation operation of 10305 Island Coalface in Baodian coal mine, the relation between P-wave velocity and stress was analyzed, and the seismic hazard assessment method by using passive computed tomography in 10305 Island Coalface was established. Meanwhile, the indexes of P-wave velocity anomaly and velocity gradient anomaly were proposed to evaluate the stress concentration or seismic hazard zones, and the discrimination standards were also constructed. Finally, the assessment method was applied in 10305 Island Coalface. The results show that P-wave velocity and stress presents characteristics of positive correlation. The high velocity anomalies and velocity gradient anomalies are always located in the regions adjacent to the narrow goafing side of 10305 Island Coalface, which are basically similar to the anomaly areas of seismic hazards. The tomography detection practices show that it is feasible for seismic hazard assessment and anomaly region division during island coalface mining, and the hazard assessment accuracy is high. Thus, the passive computed tomography can improve the monitoring and pre-warning level for seismic hazards in underground mining.

Key words: island coalface, seismic hazard, wave velocity, tomography detection, velocity gradient