煤矿井下
- 网络underground mine; coal mine; coal mine underground
煤矿井下煤矿井下
underground mine
地下煤矿,Underground Coal... ... ) coal mine underground 煤矿井下 ) underground mine 煤矿井下 ) coal mine 煤矿井下 ...
coal mine
煤矿井下作业,Work in coal... ... ) underground mine 煤矿井下 ) coal mine 煤矿井下 ) underground coalmine 煤矿井下 ...
coal mine underground
井下采空区,underground... ... ) down hole 井下 ) coal mine underground 煤矿井下 ) downhole switching valve 井下开关 ...
underground coalmine
煤矿井下作业,Work in coal... ... ) coal mine 煤矿井下 ) underground coalmine 煤矿井下 ) underground coal mine 煤矿井下 ...