Hundreds of members of South Africa's National Union of Mineworkers started a strike Feb. 21 at the Optimum coal mine owned by the Gupta family amid concerns over the operation's viability, Reuters reported the same day.

A spokesman for the union said workers are worried over wages after several banks cut all ties with the Guptas due to reputational risk, though the family has repeatedly denied links to former South African President Jacob Zuma, whose presidency had been plagued by corruption, or to any other wrongdoing.

The strike follows a warning from South Africa's Department of Mineral Resources that the Optimum mine could be closed for failing to operate a water desalination plant in the community, violating license terms.