Analysis on feasibility of upper protective layers mining in contiguous seams with coal and gas outburst hazard

In order to solve the gas prevention of short outstanding risk for coal seams mining in Shaqu Coal Mine,this paper took theoretical analysis,numerical simul ation and field observation to analysis the possibility of the 22201 working face as the protective layer mining.The results showed that while it was a protective layer mining for No. 2 coal seam,the depth of destroyed floor would be 26 ~ 28 m,which was greater than the vertical dimension between No. 3 + 4 and No. 5 coal seam. This meant tha tNo.3 + 4 and No. 5 coal mine would be in protective layer while No. 2 coal seam was mining. The No. 3 + 4 and No.5 coal seam would decreased to be 0. 5 MPa and 1. 0 MPa while No.2 coal seam was mining. The permeability under protected coal seam in effective pumping mining range increased significantly while No. 2coal seam was mining and made the maximum 5. 2 x 10- 3μm2. At last,this paper test the gas concentration of pumping mining drilling in puncture layer floor,the results showed that the maximum of gas concentration would reach 80% and made the results better.