36 bodies were recovered within two days from an abandoned mine in South Africa.. What happened?

Police in South Africa announced on Tuesday that they had recovered the bodies of 36 illegal miners from an abandoned well after two days of rescue operations, explaining that they had been cordoning off the site for months to remove them.
After 9 bodies were recovered on Monday using a basket and a crane, 27 of the miners who were taken out on Tuesday were declared dead, according to a police statement, while dozens were able to get out of the mine, weak but alive.
Since the operation is expected to last 10 days, this provisional death toll supports local estimates that indicate that there are more than 100 bodies in the basements of the mine located about 150 kilometers southwest of Johannesburg.

Mine shafts

“Last week we received a message from underground indicating that there were more than 109 bodies,” said Levis Belosa, 41, a spokesman for residents of the shantytown in Khoma.
A video sent Monday to Agence France-Presse by the non-governmental organization “MACOA”, which defends communities affected by mining activities, showed what appeared to be dozens of bodies in the dark mine corridors.