Study On The Gas Drainage Technology By Crossing Boreholes In Floor Rock Roadway In Yangquan No.5 Coal Mine 8406 Mining Face

In Yangquan mining area of Shanxi Province,the coal bearing strata has high ground stress,high gas pressure and weak air permeability.It is difficult to drill holes in the coal seam,and the gas extraction effect is poor,which has become the prominent problems for the safe and efficient mining of coal in the mining area.In this paper,the 8406 working face of Yangquan Minmetals Mine is taken as the experimental research object.By means of field experiment,laboratory test,theoretical analysis and numerical simulation experiment,the gas foundation parameters of No.15 coal seam on the test working face are obtained,and the outburst risk of coal seam on the 8406 working face is analyzed.Combined with the main characteristics of the 8406 working face,the floor rock roadway and borehole through bed of the 8406 working face are designed together with the experimental mine,and the depth of the surrounding rock loosening zone of the floor rock roadway is measured.The new sealing technology of the crossing boreholes of the floor rock roadway is put forward,and the technical scheme of the gas extraction system of the crossing boreholes of the floor rock roadway is obtained.Based on the field observation data of the working face,the correlation laws of the amount and concentration of gas extraction,the negative pressure and the time of gas extraction from the crossing boreholes were studied,and the gas extraction effect from the crossing boreholes in the floor rock penetration layer in the test area was analyzed.Grasp the results of the inspection index of the outburst elimination effect in the test area and analyze the effect of the outburst elimination technology realized by different schemes.In this paper,a solid-gas coupling model was established for gas extraction from crossing boreholes in floor rock roadway.The gas extraction effect of crossing boreholes in floor rock roadway under different working conditions was analyzed,and the reasonable layout parameters and drainage technical system parameters of boreholes in floor rock roadway in test face were proposed.The research results of this project provide guidance for the regional outburst prevention technology of the outburst coal seam which does not have the condition of mining protective layer in other mining area.The paper included 53 figures,16 s tables and 71 references.