Composite Slag Discharging Drilling Technology in Soft and Outburst Coal Seam

Abstract:

In order to improve the gas drainage hole drilling depth and the extracting effect, based on composite slag discharging technology with medium air pressure (0.7～1.2MPa), the field test was carried out by using screw drilling tool assembly with different specifications matched with corresponding process parameters. Comparing the different application conditions, the best bottom hole assembly and the matching technologies were selected to achieve high-efficient long borehole construction in whole coal seam.