New reaming technology for high position and large diameter directional drilling in roof

In view of the problems of low drilling efficiency and short service life of the drill tools in the construction of large diameter roof directional drilling，this paper puts forward the technology of torsion impact rotary reaming and reverse pulling reaming.On the basis of analyzing the feasibility of the existing torque hammer products for reaming in coal mines and the technical difficulties of reverse broaching and reaming，the selection and modification of torque impactor were completed，and a reverse broaching reamer with ø216/110 mm type was developed，and the exploration test was carried out.The test results show that the torque impactor has remarkable effect on improving the reaming efficiency of the high directional hole in the roof，which is 65% higher than that of the conventional reaming technology.The developed reverse broaching reamer has the advantages of feasible working principle，reliable operation，ensuring the efficiency of broaching and reaming，and improving the working condition of reaming drill tools，which has positive significance for improving the service life of reaming drill tools.