Micro Seismic Monitoring Research on Roof Fracture at the First Fully Mechanized Mining Face in Special Thick Coal Seam Under Goaf

In view of the characteristics of complex pressure features and lack of engineering examples at the first fully mechanized face in special thick seam under goaf, taking Xiegou Coal Mine 23103 fully-mechanized working face as the background, we use high-precision micro seismic monitoring technology to study the roof fracture and its evolution process. Results show that the high energy micro seismic events at coal face occur in front of the coal wall of 80 m, and the events distributed in the high roof （from 30 m to 70 m） have obvious periodicity; the periodic fracture and sinking of high roof make the low roof（0 to 30 m） occur persistent rupture in front of the coal wall of 30 m; goaf micro seismic events are more distributed behind the coal wall within the scope of 0 to 30 m, and more focused on the material lane near to coal wall; No. 8 coal goaf above the roof of 70 m has no obvious seismic events.