The Association of Mineworkers and Construction Union (AMCU) announced on Monday that it is planning to strike at Sibanye-Stillwater's local platinum operations, expanding an earlier stoppage affecting its gold facilities.
The new strike would begin on Jan. 22 and involve around 12,500 of its members, AMCU said.
"Our South African PGM operations have been preparing for this outcome and as such have strike contingency plans in place to minimize the possible impact of a strike," Froneman said in a statement.
Froneman added that the firm's U.S. platinum group metals (PGM) operations were providing support during the strike.
Sibanye-Stillwater said while the expanded strike is allowed under the Labour Relations Act, it is within constrained parameters and the company would seek legal advice on the merits of the strike in the platinum division.
The company said it currently employs about 17,400 people at its local PGM operations, with AMCU representing about 56 percent of the staff at the Kroondal operations and 71 percent of the employees at its Rustenburg operations.
Sibanye-Stillwater's shares fell 1.73 percent to 10.23 by 0831 GMT, compared with a 0.21 percent rise in the All Share index.
(Reporting by Nqobile Dludla; Editing James Macharia)
