underground mining
短语词组
- underground col mining 地下采煤
- underground coal mining 地下采煤
- underground E mining 地下开采
- Underground melting mining 地下热熔开采
- underground d mining 地下采矿
- underground coal mining method 地下采煤方法
- underground bench mining 井下梯段采矿法
- underground trackless mining vehicle 地下无轨采矿车辆 返回 underground mining