Drilling Technology and Equipment of Large Diameter Borehole in Coal Seam of Underground Coal Mine

Based on the characteristics of large diameter borehole in coal mine, the construction technology of large diameter drilling with “pilot borehole construction and reaming” is proposed, and the matching ZDY12000LD high power drilling rig, φ400/127 mm large diameter spiral drilling rode and φ450/153 mm, φ650/450 mm large diameter reaming drill bit and other key equipment are also proposed, which effectively ensures the quality of large diameter borehole. The drilling with diameter borehole of 650 mm and the maximum hole depth of 75 m is completed by field test.