Monitoring and Early Warning Technology for Rock Burst in Working Facewith Hard Roof

Aiming at the mining conditions of hard roof and high stress, a combined monitoring and early warning technology for near and far fields was proposed. the ARAMISM/E microseismic monitoring system was used for the monitoring of the far field, the time-space evolution regularity of the microseismic events in the working face during coal mining was analyzed, the early warning indicatorb, η, M_mand A (b) of the rock burst were determined to be 0.58, 1.52, 2.32 and 7.85 respectively, and a combined indicator system was set up for the prediction of the rock burst. The electromagnetic radiation intensity and the coal body stress were used for the monitoring of the near field, the prediction value of the electromagnetic radiation intensity of the working face and its two gateways were determined to be 154 mV, 131 mV and 136 mV respectively. The rock burst hazard was evaluated according to the the change of the coal body contours. The application examples showed that several rock bursts were successfully predicted by using the combined monitoring and early warning technology of the near and far field of the rock burst, and the better prediction effect was achieved.