Study on Laws of Overburden Activity in High Gas Coal Seam

To improve the effect of pressure relief gas drainage in overburden strata in goaf of gassy coal seam, the micro-seismic events of overlying strata in goaf during the mining process are monitored and recorded by micro-seismic monitoring technique. The fracture characteristics of the rock are analyzed to obtain the spatial location of the mining fractured zone, and then to determine the high gas concentration area of the overlying strata. The monitoring results show that the working face pressure step distance is about 20 m and the height of the mining fracture zone is about 45 m during the recovery period, so it is most reasonable to determine the vertical distance of the high-pumping roadway to be 38 m, and the theoretical calculation method is adopted to verify this.