1.Downhole drilling machine: When drilling a downhole gun hole with a aperture less than 150 mm, in addition to the application of a rock drill, it can also be used to drill a small diameter of 80 ~ 150 mm. When drilling a gun hole with a diameter of less than 70 mm in coal or softer mineral rock, it is generally used to drill or air drill, driven by a motor (or air motor) to drill the drill pipe, and the rock (coal) chips drilled out are discharged through the spiral groove on the drill pipe.
...
2025-08-16 03:49
2665