Mining strikes in South Africa appear to be spreading with about 15,000 gold miners walking off the job near Johannesburg.
Another illegal stoppage has hit Gold Fields, the world's fourth biggest gold miner.
Strikers marched from one mine to another on Monday. Many were armed with sticks, spears and machetes.
Riot police watched as they filled a two-lane highway for over a mile.
CNN reports that open threats were made to kill those who had gone to work.
Talks to end the Lonmin strike failed to start as scheduled when the majority of miners stayed away despite a deadline of Monday.
Labour unrest culminated on 16 August at the Marikana platinum mine during clashes with police in which 44 people were killed.
Police said they opened fire in self-defence.