目前煤矿岩巷开拓任务重，岩巷机械化掘进成为各矿普遍存在的技术难题。

Developing rock roadway of coal mine is a hard task at present. Mechanized drivage of rock roadway has become a common technical problem of every coal mine.

youdao

目前煤矿岩巷开拓任务重，岩巷机械化掘进成为各矿普遍存在的技术难题。

Developing rock roadway of coal mine is a hard task at present. Mechanized drivage of rock roadway has become a common technical problem of every coal mine.

youdao