More than 900 South African miners have been rescued after they were trapped in a gold mine for 24 hours due to power loss.

The incident is reportedly to have happened on Wednesday night after a violent storm that knocked out power supply was witnessed thereby trapping the miners inside Beatrix mine which is in Welkom town, 290km south-west of Johannesburg.

Angry family members had gathered near the mine waiting to hear news of their relatives, who had spent more than a full day underground, local Medias reported.

According to James Wellsted, a spokesman for managing company Sibanye-Stillwater which owns the Beatrix mine, the miners had stayed close to the shaft to ensure they were in a well-ventilated area with ready access to food and water being delivered.

“(We kept them there), rather than trying to use a secondary escape way, which would have entailed a four hour walk,” he told South African medias.

South Africa’s Association of Mineworkers and Construction Union (AMCU) had said Thursday it was “extremely concerned” about the situation.

South Africa is a leading gold producer, but safety in the industry is often questioned.