Two men believed to have been mining illegally were killed in Kleinsee in the Northern Cape on Monday.
Northern Cape police spokesperson Captain Sergio Kock said three men “were busy with mining” when the hole they were in collapsed on them.
The incident happened close to the Kleinsee traffic testing grounds.
Two men, 24 and 29, were retrieved from the hole and taken to the Komaggas Clinic in Springbok.
Kock said they were declared dead on arrival.
The third man, 21, was being treated at a hospital in Port Nolloth.
Local disaster management and police officials were on the scene.
An inquest was opened and investigations are continuing.
Kock had not yet responded by the time of publishing to questions to confirm whether the men were mining illegally, if they were looking for diamonds, and if the site was the same location as a fatal collapse six years ago.
In May 2012, the bodies of 10 illegal miners were recovered from a disused diamond mine in the small West Coast town, News24 previously reported.
The tunnels had collapsed just a month after the mine had closed them.
An illegal digger was rescued and 11 reportedly escaped and alerted police.