The drilling mining method is a new Coal-mining method.

钻机采煤法是一种新型的采煤方法。

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Coal mining method and technics are core of high production and efficient mine's building.

采煤方法及工艺是高产高效矿井建设的核心。

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Coal mining method and technics are core of high production and efficient mine's building.

采煤方法及工艺是高产高效矿井建设的核心。

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