A DESIGN FOR WHOLE HOLE REVERSE CIRCULATION DRILLING

Air driven hollow DTH hammer is applied,along with a set of dual wall drilling pipe and a specially designed reverse circulation bit,to conduct continuous coring reverse circulation drilling.The core specimen acquired have some advantages,such as high coring recovery rate,good core quality and better representativeness.The tool was used for the exploration of gold and copper mine in complex geological environment.Drilling efficiency increased by 3 times comparing to the ordinary drilling tools.The cost of the drilling was reduced to 1/5-1/8 of the ordinary one's.The tool can be used for the ore exploration and mining in complex geological condition to derive cores.