Technology and equipment of large diameter borehole construction applied to prevent and control pressure bump in coal mine

In order to solve an irrational pressure released effect problem of the borehole construction in the pressure bump seam of Changcun Mine, Henan Energ y Yima Group, a borehole forming dfficulty and key point of a pressure released borehole was analized in a pressure bump seam, a high speed, high torque and long st roke drilling rig with a wide blade auger stem was applied to realize a high efficient operation procedure with a middle rod added and a rear drilling handling and a drillin g technical method with a water drilling medium and wide blade auger stem. A trial operation of the drilling rig with a wide blade auger stem was conducted in driving fa ce of No.21220 seam lower gateway in Changcun Mine. The trial results showed that the auxiliary time of the construction was reduced by the optimized operation proc edure, the combination of the water drilling medium and the wide blade auger stem could be applied to improve the dust removal efficiency and to realize a rapid and sa fety construction target of the large diameter pressure released borehole. The max diameter borehole drilled was 193 mm and the drilling depth of the borehole was exp anded from 20 m to 40 m. The pressure released affect was obvious and the driving efficiency of the mine gateway was improved by 10% and could provided the guara ntee to the on-time connection and mining of No.21220 coal mining face.