Study and Application on Pressure Releasing and Permeability Improved Technology with Hydraulic Flushing in Floor Gateway

In order to investigate the effect of the pressure releasing and permeability improved technology with hydraulic flushing in floor gateway to improve the s eam permeability and to improve the gas drainage rate, a trial was conducted on the pressure releasing and permeability improved technology with hydraulic flushing in No.' 1259 (3) floor gateway of Puxijing.The results showed that the radius of the pressure releasing and permeability improvement with the hydraulic flushing borehole co uld reach 4-5 m and would be 1.6-2.0 times higher than the influence radius of the gas drainage with a conventional borehole.Within half month after the hydraulic flushi ng measures conducted, the average gas drainage concentration of the borehole was 2.77 times higher than the conventional borehole, the average gas flow value was 3.43 times higher than the conventional borehole, the effect of the pressure releasing and permeability improvement was relatively remarkable, the seam permeability w as improved and the outburst danger was reduced.