A building collapsed above a gold mine in South Africa on Friday, trapping dozens of people before they were saved. After several hours, only three people remained missing, a union spokesman said.

Manzini Zungu, spokesman for the Association of Mineworkers and Construction Union, said the building collapse had trapped workers above ground, and dozens of miners below ground.

The incident occurred at the Makonjwaan Gold Mine in the town of Barberton in the eastern Mpumalanga province, Zungu said.

The three people who are still missing worked above ground and were trapped in the building, said Russel Meiring, spokesman for the private emergency service ER24. Paramedics estimate that 76 people were brought to surface, Meiring said. The rescued miners had no serious injuries and were taken to a local hospital for treatment, he said.

The cause of the collapse is believed to be a sinkhole, Meiring added.

This is the second accident in a South African mine in the past two weeks, Zungu said.