strip extraction coal-pillar mining的意思|示意
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条带提取煤柱开采
strip extraction coal-pillar mining的网络常见释义
条采煤柱回收 ... strip extraction coal-pillar mining 条采煤柱回收 coal pillar mining under stress 煤柱应力下开采 pillar coal mining method 柱式采煤法 ...