The death total from the unrest rose to 48 when a striking miner died after being shot by a police rubber bullet near the platinum-belt town of Runstenburg.
The rand fell 2% against the dollar as investors pulled back from Africa's biggest economy amid fears the ruling African National Congress (ANC) cannot stop the spreading unrest.
President Jacob Zuma has been criticised for his low-key response to the most damaging bout of industrial action since the end of apartheid, after police killed 34 strikers at Lonmin's Marikana platinum mine in August.
More than 75,000 miners are out on unofficial strikes and tensions with security forces and mining bosses are running high.
"There is fuel available across the country, so the issue is not fuel supply, but the challenge is delivering it safely to our retail sites," Shell said yesterday after invoking a "force majeure" clause that allows it to break contracts due to situations beyond its control.