They are a husband and wife running away from their pit.
Abandoning duties and running away from a pit was seemingly called Ketsuwari.
Such wrongs were mainly done by lazy miners who were in over their head in debt.
Some male miners ran away because they had an affair with married women, who were violently punished and made an example if they were caught by the personnel supervisor later.
However, the personnel supervisor even sometimes acted as a go-between for young couples who ran off together without punishing them.