Amcu is insisting that gold mines more than double the wages of entry-level workers, raising the stakes for pay talks set for early next month.
Anglo American Platinum's operations were shut after workers stayed away following violence caused by union tension, say a spokesperson and police.
Anti-apartheid activist Dr Mamphela Ramphele has resigned as chair of Gold Fields, intensifying speculation she is about to launch a political party.
Gold Fields will list most of its local assets as a separate company, testing investor appetite for a mining industry battered by labour unrest.
Harmony Gold's Kusasalethu mine could be shut permanently, ending about 6 000 jobs, after managers received death threats and police were shot at.
AngloGold Ashanti has become the latest miner to report a surge in output-disrupting safety stops as it unveiled a fall in fourth quarter earnings.