坑こう内ない

noun, noun which may take the genitive case particle 'no'

inside a mine; within a pit

Refers to the interior of a mine or pit; often used in mining contexts.

• 坑こう内ないの安あん全ぜん確かく認にんは最さい優ゆう先せんだ。

  Safety checks inside the mine are the top priority.

• 坑こう内ない作さ業ぎょう員いんはヘルメットを着ちゃく用ようする。

  Workers inside the mine wear helmets.