The 12,000 tonne per year Sandouville facility, located at Le Havre - France's second largest industrial port - is currently owned by French mining group Eramet.

Sibanye said the transaction, slated to conclude by the end of the year, was "the second step in Sibanye-Stillwater's battery metals strategy, building on the investment in the Keliber lithium hydroxide project" - a deal the company unveiled in February.

"Post a successful due diligence, the acquisition is seen as a low-risk entry into the nickel beneficiation business and the initial focus will be on ramping up throughput as per the existing Eramet plans," said Sibanye.

Analysts at Canadian investment bank BMO said Sibanye's measured approach to battery metals "reflects the technological risk in the battery metals space with respect to the evolving chemistry and make of batteries".

"However, with exposure to lithium and nickel, both key elements in different types of batteries being used or under development, Sibanye-Stillwater seems to be well positioned," said BMO.