... All hydraulic crawler drilling jumbo is mainly used to drill blastholes for tunneling construction in coal mine, nonferrous ... is designed with two drilling booms, advanced hydraulic rock drill system, self-return and anti-jamming mechanism for ... in underground mine or tunnels, and it also can drill anchor holes upward. With modular designed, this small ... x H)5.2m x 4.5m Underground Blast Drill Rigs