At present, large-diameter pneumatic rock drills with a drilling diameter of 75-100mm or even larger diameters are used in marble mines to drill through holes for wire ropes. With the application of wire saw machine in granite mining, it is also necessary to drill a large hole through-hole, and hard granite can not use ordinary hydraulic drill drilling, so it must be used for large hole pneumatic drill used in granite mining Large-diameter pneumatic rock drills with a drilling diameter of 90-104mm are used in granite mines. Because the diameter of the borehole increases, the rock drilling powerhead of the large-aperture pneumatic rock drill adopts the down-the-hole pneumatic impactor. The feed propulsion adopts a chain-type feed mechanism driven by an air motor, and another air motor is specially used for the rotary drive of the drill pipe to ensure a strong enough feed propulsion force and reliable rotary motion of the drill bit. Therefore, the air consumption of all-pneumatic large-diameter rock drills is between 7-12 cubic meters per minute, and mines must be equipped with air compressors with sufficient capacity. The control unit of the rock drill adopts a separate structure, and the rock drill is equipped with a dust collection device. The large-aperture pneumatic rock drills currently used in marble and granite mines are designed as multi-functional models that can perform vertical, horizontal, and any angle drilling operations. The order of intersection hole drilling is related to the number of intersection holes, drilling depth, etc. Usually, the horizontal hole is drilled first, and the vertical hole is drilled later. This is because the drilling speed of the horizontal hole is slow, the positioning is difficult, and the vertical hole is relatively easy to drill. If the holes do not intersect, the cost and difficulty of re-drilling vertical holes are low. Or in accordance with the order of drilling deep holes first, then drilling DTH, this is also because if drilling is needed, the cost and difficulty of drilling DTH are low and less. If three holes are drilled to intersect, regardless of whether the last remaining vertical hole or horizontal hole, the shallowest hole should be selected as the most drilled hole, which is also considered to reduce the cost of hole repair and the difficulty of hole repair.
