Application of hydraulic reverse circulation coring in exploration of concealed geological abnormal body in coal mine

According to the characteristics of shallow depth of collapse column and fault coring borehole in mining face, the hydraulic reverse circulation coring method of horizontal hole is proposed. The working principle and technical characteristics of hydraulic reverse circulation coring under the condition of near horizontal hole in coal mine is analyzed. The Φ89Φ42 mm double-wall drill pipe, multiple specifications of diamond composite core bit, double-wall water feeder, and orifice sealing device and other reverse circulation core supporting drilling tools are designed. The underground field tests through faults and collapse columns have been carried out in Sihexi Mine, and the results show that it is completely feasible to apply near horizontal hole hydraulic reverse circulation coring to the exploration of small faults and collapse columns in mining face of coal mine.