Transnet, which operates South Africa's freight rail network and all of the country's ports, declared force majeure at its ports on Thursday after some workers began a strike over wages.
"The strike may affect the Tshipi Borwa Manganese Mine (Tshipi) operations with regards to its rail logistics and port operations," Jupiter, which owns 49.9% of the Northern Cape mine, said in a statement.
Jupiter said while rail operations had been disrupted by the strike, ship loading was continuing.
Current port stocks of manganese ore from Tshipi are sufficient to load vessels scheduled for the next 10 days and management was exploring the use of trucks to haul the mineral to port, Jupiter said.
The United National Transport Union (UNTU) and the South African Transport and Allied Workers' Union (SATAWU), which together represent most Transnet workers, this week turned down Transnet's offer of a wage rise of 3%-4%, saying it was below South Africa's annual inflation rate, which was 7.6% in August.
UNTU started their walkout on Thursday, while SATAWU will join the strike on Monday.
(Reporting by Nelson Banya; editing by Jason Neely)
