Impala Platinum (JSE: IMP) has suspended mining for four days at its Rustenburg complex in South Africa after six recent worker deaths triggered what the company described as a comprehensive safety reset.

The platinum-group metals producer recorded four fatal workplace injuries during the financial year ended June 30, followed by two underground locomotive-related fatalities in July. The Rustenburg complex employs about 51,500 people and accounts for almost half of Implats’ total production, making any interruption there material to the company’s operating base.

During the suspension, Implats said it will carry out workplace inspections, targeted training and a mass employee engagement session. The company will also appoint independent specialists to assess its safety systems and recommend improvements.

Implats said the effect on production will be assessed once operations resume. The company did not provide an output estimate for the four-day halt.

“Our aspiration is that every employee returns home safely every day,” the company said.

The halt underscores the safety challenges facing South Africa’s deep-level mining industry, where some of the world’s oldest platinum mines are also among the deepest and most expensive to operate. Mine safety performance is closely watched by companies, workers and regulators in the country because underground operations rely on large workforces, complex transport systems and continuous risk controls.

South African producers, including Implats and Sibanye-Stillwater (JSE: SSW) (NYSE: SBSW), account for most global platinum production. Platinum is used in catalytic converters that reduce harmful emissions from gasoline and diesel vehicles.