Comparative experimental study on drilling methods of hard rock borehole passed through strata in Huainan Mining Area

According to hard rock drilling problems with the low drilling rate encountered by borehole passed through strata in Huainan mining area，the drilling principles of three drilling methods，percussion-rotary drilling，pneumatic percussive-rotary drilling and high pressure hydraulic percussive-rotary drilling were analyzed，the corresponding drilling tools and bits were optimized.The comparative experiment of drilling rate about three drilling methods was finished in the typical mine，Pansan mine.The results showed high pressure hydraulic percussive-rotary drilling was the highest drilling rate，up to 12.47 m/h.The drilling rate of pneumatic percussive-rotary drilling was the second,and the max.drilling rate was 11.42 m/h.The drilling rate of Pneumatic percussive-rotary drilling was the second，with maximum drilling rate 11.42 m/h.The drilling rate of percussion-rotary drilling was the lowest drilling rate，with maximum drilling rate 3.75 m/h.Therefore，pneumatic or high pressure hydraulic percussive-rotary drilling method was recommended preferentially in hard rock drilling of Huainan mining area.