The incident happened at the end of a shift at the mine in Rustenburg, west of Pretoria, while staff were being carried back to the surface.

All the 75 injured workers were taken to hospital, with officials saying 14 of them are in a critical condition.

Nico Muller, head of mine operator Impala Platinum Holdings (Implats), described the event as "the darkest day in the history of the Implats", adding an investigation into what caused the lift to drop was under way.

All operations at the mine were suspended on Tuesday.

There is also a government investigation taking place.

A spokesperson said all 86 of those killed or injured were in the lift, and some have "serious compact fractures", adding it was a "highly unusual accident".

The lift in question has three levels, all of which can hold 35 workers, with the shaft itself being 1km (0.6 miles) deep, the firm said.

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The Impala Rustenburg mine, which has nine shafts, was the world's largest platinum mine by production last year.

Last year, South Africa suffered 49 deaths from mining incidents, government figures showed, down from 74 the year before.