South Africa are trying to reach more than 200 illegal miners reported trapped underground in an abandoned gold shaft in a suburb 20 miles east of Johannesburg.
The miners may have been trapped deliberately by a rival group as they worked to try and find pieces of precious metal left behind after industrial operations in the shaft ended several years ago, a spokesman for ER24 said.
They are understood to have been trapped in the mine outside Benoni, in an industrial area known as the East Rand, since Saturday morning. They were discovered after emergency services staff heard screaming while conducting a routine drill in the area.
Around 30 miners are close to the surface, where a large boulder is blocking the entrance. They have communicated to rescue workers than they are 200 people trapped in total and the rest are down a steep tunnel.
Werner Vermaak, a spokesman for ambulance service ER24, said rescue workers had to wait several hours for specialist equipment including a crane to move the boulder without destabilising the ground around it, but they had now begun work.
"At this stage we are not sure how many miners are injured,” he said. "Once they are freed medical workers will start to assess them and proved treatment where necessary. We hope that we will be able to bring them all out without problems.”
Water has been passed through gaps to the miners – the temperature in the area was 80F (27C) by 3pm.
“We understand that they have been there since yesterday morning,” Mr Vermaak said. “Many of these guys go down for several weeks at all time, so we expect that they will have supplies with them.”
He said that the way the miners were trapped by the boulder suggested foul play. “Sometimes it happens that rival groups close the entrance off,” he said.
Mining is one of South Africa’s biggest industries and disused mines cover the landscape around Johannesburg. Mining firms are expected to secure the areas to prevent illegal access but the security is frequently breached by people eager to search for scraps left behind by the commercial operations.
As a result, such entrapments are almost a weekly occurrence, although rarely on the scale of the latest incident near Benoni.
“They are very common in this area particularly but this is probably the largest one we have seen for quite some time,” Mr Vermaak said.