(Bloomberg) -- At least 11 people died at a mine owned by Impala Platinum Holdings Ltd. when an elevator transporting workers to the surface failed, the worst accident in the South African company’s history.

On Monday afternoon, a cage hoisting miners to the surface, “unexpectedly started descending,” before its plunge was halted when the lift’s counterweight became trapped, Johannesburg-based Implats said Tuesday. Another 75 workers were hospitalized.

South Africa’s mining industry has been struggling to reduce such fatalities. Deaths have climbed by almost a fifth to 52 so far this year, the highest tally since 2021, according to data provided by Implats and Minerals Council South Africa, an industry lobby group.

“This is the darkest day in the history of Implats,” Chief Executive Officer Nico Muller said in a statement. Operations have been suspended and the cause of the accident is being investigated.

The accident at Implats’s sprawling Rustenburg complex comes as falling prices add to the pressure on some of the deep-level shafts, which are running out of commercially viable ore.

In 1995, in the worst post-apartheid mining accident 105 workers plunged more than 2 kilometers (1.2 miles) to their deaths at the Vaal Reefs Mine, then operated by a unit of Anglo American Plc, after a cable supporting a cage was severed by a runaway ore train.

Implats shares fell as much as 8.7% and traded 8.5% lower by 3:44 p.m. in Johannesburg.

“The mining industry is a difficult sector, it’s a dangerous sector, it’s a dirty sector,” Mineral & Energy Resources Minister Gwede Mantashe said in a briefing broadcast on Johannesburg-based SABC. “When you get into mining, we understand that.”

Mantashe, a former union leader, said there’s been an effort to improve safety and called for patience in allowing processes to run their course. 

All safety systems on the lifts had been tested and were operational, so the investigation needs to determine how the accident happened, CEO Muller said at the briefing. There are a number of ways relatives of the deceased workers would be compensated, including offering their job to family members, he said.     

After the accident at Implats’ 11 Shaft in the northern city of Rustenburg, ambulances from other operations were sent to the mine to transport injured employees to nearby hospitals, Japie Fullard, chair of the Minerals Council’s CEO Zero Harm Forum, said in a separate statement.

Implats’s Rustenburg operations — which take place at an average depth of 870 meters (2,853 feet) underground — account for about a third of production. Impala gained control of Royal Bafokeng Platinum Ltd. in May to extend the life of the complex, from which the company has been producing platinum for more than five decades.

“It’s a painful situation that can’t be accepted,” Livhuwani Mammburu, spokesman for the National Union of Mineworkers said by phone, adding that South African mineworkers typically support 10 dependents. “It’s a big loss.”  

--With assistance from William Clowes.

(Updates with comments from minerals minister and CEO from briefing)

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