small coal mines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 belated enforcement of mining safety standards has led to closure of many small mines and temporary shortage of coal.
採礦安全標準姍姍來遲后，許多小煤礦被關閉，導致了暫時性的缺煤。
