坑こう内ない掘ぼり炭たん鉱こう

noun

underground coal mine

Technical term for a coal mine where extraction is done via underground shafts and tunnels, as opposed to open-pit mining.

• この地ち域いきにはかつて多おおくの坑こう内ない掘ぼり炭たん鉱こうがあった。

  There used to be many underground coal mines in this area.

• 坑こう内ない掘ぼり炭たん鉱こうの労ろう働どう環かん境きょうは非ひ常じょうに厳きびしかった。

  Working conditions in underground coal mines were extremely harsh.