短語詞組短語piston ventilation shaft layout 活塞風井設置ventilation of mine shaft 鑛井通風south ventilation shaft 南風井surface mine ventilation shaft 地麪風井uranium mine ventilation shaft 鈾鑛井通風emergency ventilation shaft 事故通風井a ventilation shaft 排氣孔tunnel l ventilation shaft 隧道通風井ventilation shaft reconstructing 風井改造 返回 ventilation shaft