The opening stability in soft weak coal layer is important to the safe production in a mine.

软弱煤层巷道的稳定性对煤矿正常安全生产起着重要作用。

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The opening stability in soft weak coal layer is important to the safe production in a mine.

软弱煤层巷道的稳定性对煤矿正常安全生产起着重要作用。

youdao