坑内 こうない 炭鉱 たんこうじゃありませんでした
kō nai horitankōjārimasendeshita

Noun
Desu Copula

The polite, past negative form of 坑内掘り炭鉱

1. Was not a pit coal mine.; Was not a coal pit.

Past/Perfective
Negative
Polite
Terminal Form