短語詞組短語coal seam uncovering 揭煤coal -seam uncovering 煤層剝露exposure degree during coal uncovering 揭煤暴露麪麪積rock cross -cut coal uncovering 石門揭煤uncovering coal 揭煤rise entry uncovering coal 上山揭煤uncovering coal plane 煤層裸露麪rapid uncovering coal 快速揭煤vertical shaft uncovering coal 立井揭煤 返回 coal uncovering