Around this time, the composer took an axe and hit his wife on the head

The composer was Einojuhani Rautavaara. The review of his opera The Mine is by Vesa Siren:

The music here is dark and heavy, as befits the story. Part of the reason for this darkness may be ascribed to the composer’s life situation. According to the composer’s free-form autobiography Omakuva [Self-portrait] (1989), when he completed the last act of the opera in 1963 his family life was hell. It was around this time that he took an axe and hit his then wife on the head, “in the grip of a Panic terror”…

One of the causes of the furious domestic arguments was the leading female role in Kaivos. Rautavaara wanted a young, girl-like singer, but his first wife Mariaheidi Rautavaara – an excellent singer but substantially different from Rautavaara’s vision for the part – demanded that she be cast in the TV production.

Read the full review here.