Rock drilling tools include: drill bit,drill rod, shank and coupling. The piston of drill rig directly impacts the shank, makes impact power reach the bit through rod by the form of stress wave, so as to work on the breakage of rock. The primary breaking way is impacting while the secondary is cutting; both are with high drilling efficiency. Usually the land surface of the earth is covered with loose, unconsolidated material such as soil, clay, silt, sand, gravel and boulders, which varies in depth from a few centimeters to hundreds of meters.Use concentric system can drill this complex formation very well.The systems are available through the whole product range the smallest being for 114 mm (4 1/2″) casing and largest size available at the moment is for 1220 mm (48″) casing.