coal wedge的用法和樣例：
例句
- Medium and small coal mines in north of Shaanxi Province generally adopt longwall remaining coal pillars support mining.
摘要長壁留煤柱支撐法開採是陝北中小煤礦普遍採用的一種採煤方法。 - The coal pillar has mode-soft behaviour, so it is possible to estimate the destabilization.
煤柱失穩還具有模態軟化特性，可以對失穩的可能性進行佑計。
