Key technologies of drilling process with raise boring
Aug 01, 2015#0183;#32;Particularly, the successful development of the raise boring machine /600 achieves largediameter shaft construction, whilst former raise boring machines can only drill smalldiameter raises. The raise boring machine /600 constructed a ventilation shaft 5 m in diameter in a coal mine and drilled a dozen deep shafts m in diameter in hard basalt at the Baihetan hydropower