单词：coal column
coal column的用法和样例：
例句
- Medium and small coal mines in north of Shaanxi Province generally adopt longwall remaining coal pillars support mining.摘要长壁留煤柱支撑法开采是陕北中小煤矿普遍采用的一种采煤方法。
- The coal pillar has mode-soft behaviour, so it is possible to estimate the destabilization.煤柱失稳还具有模态软化特性，可以对失稳的可能性进行佑计。
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