Micro-seismic characteristic and danger-relief method in rock-burst danger period of mining face under hard and thick roof of Kuangou Mine

The cause of a rock-burst in a mining face under hard and thick roof was analyzed and rock-burst prevention principle was put forward on the basis of this.Rock-burst danger period and danger area of the mining face surrounded by 3 gobs was obtained by numerical simulation and geophysical prospecting method.Micro-seismic monitoring data show that breaking height of surrounding rock in rock-burst danger period is higher than that in non-danger period,rock seismic take on a characteristic of high energy and low frequency,and mining speed should be controlled below 3.2 m/d.Roof-broken blasting between powered supports in mining face was adopted to reduce rock-burst danger degree.Electromagnetic radiation and micro-seismic monitoring show that blasting effect is perfect and coal stress ahead of mining face is reduced effectively.Mining safety in rock-burst danger period is ensured.