Striking workers at a BHP Billiton copper mine have blocked the port of Coloso in Chile.
Unionised employees from Escondida are engaged in a dispute with managers over contract terms that has lasted six weeks.
BHP said it was gradually resuming operations at Escondida, but access was blocked to Coloso, which BHP controls, after replacement workers tried to move in.
"We roundly reject the various actions that the Escondida mine is taking to break the unity demonstrated by the members of the union," Gustavo Tapia, president of Chile's FMC mining union, said in a statement.
A BHP representative told a local newspaper that it would insist on accessing the port.
Copper prices have been rising as a result of the action.
