Outburst Prevention Technology with Borehole Hydraulic Jet Through Strata in Floor Gateway

According to coal and gas outburst problems occurred in the heading process of the No. 14211 transportation gateway in XinDan Mine, in order to study and set up the borehole hydraulic jet technique and the outburst evaluation system suitable for the three soft seam deposit features in XinDan Coalfield, to rapidly elimi nate the outburst danger of the heading face and to improve the seam gateway heading speed, the outburst prevention measures with borehole hydraulic jet through th e strata in the floor gateway were applied.According the investigation of the borehole hydraulic jet influence radius, a layout of the borehole pattern was evenly set up a nd a partial coal and gas could be discharged.Thus the seam pressure could be released and the permeability of the seam could be improved.The experiment result sh owed that the borehole hydraulic jet technology passed through strata in the floor gateway would be well suitable for and uilization of the deposit features of the three s oft seam and could eliminate the outburst danger of the heading face.Thus the heading speed could be improved from the previous 40 m/month to 75 m/month and the heading efficiency was improved by 87.5%.