Study on Optimized Layout Plans of Floor Gas Drainage Gateway in Single Outburst Seam

Abstract：In order to investigate the outburst eliminated effect of the gas pre-drainage in the floor gas drainage gateway in a single out- burst seam, a floor gas drainage gateway was set at 10 m below the single outburst seam of a mine in Pingbao Company. There were four borehole layout plans proposed, including the center to center vertical projective distance of 0, 10 and 20 m between the two gateways, a vertical projective distance of 1 m between the outer wall of the seam gateway and the inner wall of the rock roadway and others. The re- sults showed that in comparison with No. 1 and No. 2 plans, the drilling distance of each group boreholes for No. 3 and No. 4 plans could reduce 20 -83 m and 11 -74 m individually, the construction time of No. 3 and No. 4 plans could reduce 100-180 min and 80-150 min individually, the maintenance and repair period of the 100 m gateway could reduce 2-3 days and the volume fraction of the gas drainage of No. 3 and No. 4 plans would be improved by 10%. After the No. 3 and No. 4 plans applied, though the stress distribution of the gateway would be concentrated and the deformation of the gateway would be high, but with the high strength bolt/steel mesh/anchor support, the gateway could meet the requirements of the mine production and safety.