JOHANNESBURG (AP) — An elevator suddenly dropped around 200 metres (656 feet) while carrying workers to the surface in a platinum mine in South Africa, killing 11 and injuring 75 — 14 of them critically, the mine operator said Tuesday.

It happened Monday evening at the end of the workers’ shift at a mine in the northern city of Rustenburg. All the injured workers were hospitalised.

Mine operator Impala Platinum Holdings CEO Nico Muller said in a statement it was “the darkest day in the history of Implats.” He said an investigation had begun into what caused the elevator to drop and the mine had suspended all operations on Tuesday.

Minister of Mineral Resources and Energy Gwede Mantashe said there would be a government investigation into the tragedy. He visited the mine and was briefed, the government said.

All 86 workers killed or injured were in the elevator, Implats spokesperson Johan Theron said. Some of the injured had “serious compact fractures,” he said. Theron said the elevator dropped approximately 200 metres, though that was an early estimate. He called it a highly unusual accident.

The huge elevator has three levels, each with the capacity to hold 35 workers, Implats said. The mine shaft is approximately one kilometre (0.6 miles) deep.

South Africa is the world’s largest producer of platinum. The Impala Rustenburg mine has nine shafts and was the world’s largest platinum mine by production last year.

The country had 49 fatalities from all mining accidents in 2022, down from 74 the year before. Deaths from South African mining accidents have steadily decreased from nearly 300 in the year 2000, according to government figures.