Microseisms detection and application of high-level gas enrichment region in overlying strata of goaf under low-permeability coal seam

In order to improve the extraction effect of pressure relief gas in overlying strata of goaf under low-permeability coal seam, using micro-seismic monitorin g technology, the evolution process of micro-seismic events in overlying strata of goaf were monitored in the process of working face advancing, then the space rupture characteristics of overlying strata were analyzed, and on the basis of micro-seismic monitoring analysis of mining fissure zone position and periodic weighting length, th e parameters of high-level boreholes for gas extraction were designed, the effects of gas extraction were checked. The results show that periodic weighting length is ab out 16 m, height of mining fissure zone is about 50 m, the quantity and concentration of gas extraction increase by 100% and 150% respectively, the microseismic monit oring technology can accurately detecting the spatial position of gas enrichment region, which can provide reliable guidance and reference for design of gas extraction boreholes.