保水采煤
- 网络coal mining under water-containing; water-preserved mining

保水采煤
coal mining under water-containing
保水采煤,coal mining under water... ... ) coal mining under water-containing 保水采煤 ) water-preserved mining 保水采煤 ...
water-preserved mining
保水采... ... ) coal mining under water-containing 保水采煤 ) water-preserved mining 保水采煤 ) hydraulic mining 水力采煤 ...
2
3
5
6