DTH Hammer Drilling

The impact rotary drilling is performed with a down-the-hole hammer (pneumatic impactor) in conjunction with a drilling rig and corresponding drilling tools. The DTH hammer is connected to the bottom end of the drill pipe, the drilling rig drives the drill pipe to rotate, and the compressed air (compressed air) enters the DTH hammer through the drill pipe to generate a certain frequency of impact force to break the rock, and at the same time use the exhaust gas to compress the hammer. The head (drill) is cooled, and the chipped cuttings are discharged out of the hole. Because the outer diameter of the down-the-hole hammer is smaller than the diameter of the drill hole, it can go down into the hole with the deepening of the drill hole (the name of the down-the-hole hammer comes from this). Compared with the air drill with impact outside the hole, the impact energy loss is very small, and it can drill deeper holes. In 1992, the No. 4 Hebei team of China Coalfield Geology Bureau used a DTH hammer to drill the hole to a depth of 410m.