underground method是什么意思

用法例句

This paper briefly analyzed breakdowns and problems of mine shearer when it is working.

简单分析煤矿井下采煤机在采煤过程中易出现的障与问题,并提出了解决办法。

Application of downward filling mining method of using all tailings and hydrogenous solidifying material;

全尾砂高水固化材料下向充填采矿法的应用