HEUNISSEN, Afrique du Sud — Hundreds of gold miners among almost a thousand trapped underground for more than a day in South Africa following a power-cut resurfaced on Friday, mining company Sibanye Gold said, as a rescue effort moved into full swing.

"Power has been restored," spokesman James Wellsted said, adding that "the first hoist has come up and brought the first batch of employees up."

By dawn, several buses carrying the freed miners had already left the site of Beatrix gold mine, in the small town of Theunissen near the city of Welkom.

Rescue operations are expected to continue for around another hour to bring up the entire group of 955 miners who have been trapped since Wednesday evening, Wellsted said.

Asked if there had been any casualties, Wellsted said there was "no indication so far that anyone has been in distress" although it had been a "traumatic experience."

Several ambulances arrived on-site overnight.

The Sibanye-Stillwater mining company earlier said a massive power outage caused by a storm had prevented lifts from bringing the night shift to the surface at the mine.

The miners have been underground for around 30 hours and nervous family members patiently gathered along the road to the shaft, kept at a distance by security guards. — AFP