Know About the Overburden Drilling System at Fr-Steel.Com
The technique Overburden Drilling Management was developed in Sweden that entails the sinking, by percussive-rotational drilling, of a drill casing through the overburden to where it seats in the essential rock. A rotary percussion drill hole is then continued to the desired depth in the rock. While the casing is being sunk through the overburden it is coupled to the drill rod and rotates and reciprocates with it. The rock bit on the end of the drill rod projects about an inch beyond the end of the ring bit with which the casing is fitted and acts as a pilot bit for the casing bit. For more than 20 years Changsha Friend Industrial Co. Ltd is a specialized and veteran integrated drill enterprise which involves in the design, make inquiries, growth developed and marketing of different kinds of product in better-quality, ready for action price and wonderful service. Friend staff all share the same quality, purpose and target, assume the same accountability and obligation. We embrac...