Rescuers are trying to reach at least 30 miners in Zimbabwe trapped underground after a shaft in an outdated gold mine collapsed.

Relatives of those trapped have been holding vigil since late Wednesday, when the accident occurred in the town of Bindura, well north of the capital, Harare.

The French news agency Agence France-Presse reports the head of Zimbabwe’s miners’ federation, Wellington Takavarasha, said Thursday that six people have been rescued.

Miners who are part of small-scale operations are said to work in unauthorized settings to avoid selling their gold to a state-owned buyer and receiving a reduced amount of foreign currency.

Gold mining accounts for 60% of the foreign currency coming into Zimbabwe.

VOA