Study of Drilling Technology of Serious Nozzle Parts in the Soft Coal Seam

Drilling implementation in place is the foundation of preventing outburst.However,when drilling in Hunan Yuanjia soft coal seam,with the problems of neck shrank,plugging hole and stuck drill caused by nozzle,the drilling drilled by electricity-coal rig only reach 6～7 m,and merely 4～5 m with the high power hydraulic rig.In order to solve this problem,developing a type of dragging,the method of casting follow-up into hole was used in serious section of the drilling nozzle.Its characteristic is casing and drill pipe drilling working together.Take the application in Huangniuling mining Co.,Ltd as an example,expounds the key operations and the application effect.