Application of medium wind pressure drilling technology for gas extraction borehole in underground coal mines

Aiming to the development of compressed air drilling technology and equipment for in seam gas drainage borehole in underground coal mines, the paper introduced the technology and selection of medium wind pressure drilling as well as the experiment carried out in Dingji coal mine and Chengzhuang coal mine. It was confirmed that medium wind pressure drilling method is an ideal technology for drilling boreholes in soft out-burst-prone coalbeds and worth popularizing in the future.