Experiment Study on Rapid Drilling and Borehole Completed in Mine Medium Hard Rock Roadway Heading

In order to improve the drilling completed speed during the heading of the air returning roadway in the west No.4 mining block of North Mine ventilation shaft in Liliangdian Mine,a theoretical analysis,mineral composition measurement and site drilling test methods were applied to the study on the rapid borehole drilling completed.The results showed that the sum of quartz and sodium feldspars was taken over 60% of the total amount of minerals in the rock,the rock hardness was medium and the wear of the drilling bits was high.When a bull bit was applied,the borehole drilling speed would fast and the borehole completed quality would be good.During the drilling operation of the 2.5 m depth blasting borehole,the 2.5 m long drilling rod could be selected for the drilling operation.When the drilling depth reached at about 2.3 m,the 3.0 m long drilling rod shall be applied to the continued drilling and a fast borehole drilling could be realized.The completed time of a single borehole drilling could be reduced from 14 min to 8 min and thus the borehole completed speed could be improved.