Johannesburg: South African rescuers raced against time on Monday to free three gold mine workers believed to still be alive after more than three days trapped underground, officials said.
The mine shaft caved in early Friday when a pillar collapsed causing a huge sinkhole at Vantage Goldfields' Lily mine in the northeastern province of Mpumalanga.
The three employees who are trapped underground were working at surface level in a steel container that plunged into the mine.
All 87 miners that were underground and working in the shaft at the time of the accident were freed within hours.
"We've received a regular audible response to signals made by the rescue team," the mine's general manager Mike Begg told a local radio news agency.
He said that the rescuers had established the location of the workers after the specialised equipment picked up audio sound on Sunday night.
"This has given us immense hope this morning... and obviously our endeavours today are flat out now focused on this area."
Abednego Magongo, of the Association of Mineworkers and Construction Union (AMCU), expressed "big hope" that his colleagues would be brought out alive.
"Everyone is working very hard. There are signs that there are people down there," he told AFP from the scene.
Thousands of tonnes of rock have been removed in the rescue effort as families of the missing workers gathered at the mine and held prayer vigils.
South Africa possesses rich mineral reserves and has some of the world's deepest mines.
The industry has been dogged by accidents, including four miners killed two weeks iago in an underground fire in a platinum mine near Johannesburg.