落らく盤ばん

noun, noun or participle which takes 'suru', intransitive verb

cave-in; roof collapse; rockfall

Mining and tunneling term for a collapse of the roof or wall. Used as a noun or with する to describe the event.

• 坑こう道どうで落らく盤ばんが発はっ生せいし、作さ業ぎょう員いんが閉とじ込こめられた。

  A cave-in occurred in the mine tunnel, trapping the workers.