大断面巷道掘进
large section tunnel advance
井巷掘进
tennel excavation
TUNNELLING
shaft digging
Shaft and Lane Excavation
勘探平巷掘进技术
prospecting drifting technology
煤巷掘进面
driving face of coal roadway
岩巷掘进
deading
opening drifting
stone drifting
excavation of rock laneway
rock drift driving
drift heading in rock
rock tunneling
rock driving
driving rock roadway
rock drift tunneling
deadwork
development work in coal