And taking roadway protection without coal-pillars in mining engineering courses as a case, the paper described in detail the operation of this process.

并以矿业工程课程中的无煤柱护巷问题作为案例对象，详细阐述了此流程的运行过程。

youdao

And taking roadway protection without coal-pillars in mining engineering courses as a case, the paper described in detail the operation of this process.

并以矿业工程课程中的无煤柱护巷问题作为案例对象，详细阐述了此流程的运行过程。

youdao