Here, the working encountered large mined-out area at one side and free surface of hill slope at the other side.

在这里，工作遇到一面山坡和自由表面在对方大采空区。

youdao

Here, the working encountered large mined-out area at one side and free surface of hill slope at the other side.

在这里，工作遇到一面山坡和自由表面在对方大采空区。

youdao