Sibanye Stillwater said on Friday it had raised the estimated total cost of its Keliber lithium project in Finland by 17% to 783 million euros ($880 million), mainly due to additional regulatory requirements and changes to the scope of the venture.

The Johannesburg-based company owns 79.8% of the Keliber project, which is expected to produce about 15,000 metric tons of battery-grade lithium annually for at least 16 years, starting in 2026.

"Revised total capital for the development or construction stage of the project to the hot commissioning stage of the refinery ... has increased by 116 million euros to 783 million euros," Sibanye said in an operational update.

A total of 508 million euros had been spent on the project by the end of March 2025, Sibanye added.

The 2025 capital expenditure forecast for the Keliber project has also been increased to 300 million euros from 215 million euros.

Last August, Sibanye said it had secured 500 million euros of debt financing, partly funded by the European Investment Bank, to help bring the Keliber project to production from 2026.

Construction of the project is "well advanced", Sibanye said, with commissioning of the refinery on schedule for the first quarter of 2026.

Sibanye, which mines gold and platinum group metals used to curb toxic emissions from vehicles, has recently diversified its portfolio to include metals such as lithium, which are key in clean energy technologies amid a global drive to fight climate change.