The unprecedented scale of the unrest, including rioting and looting, has worried many residents who stocked up on goods, emptying supermarket shelves.

The workers voted by a majority to go on strike after rejecting a salary adjustment offer from the company and amid opposition to a flexible working hours plan.

Chile's overall copper production declined 0.4% year on year in August to 3.76 million tonnes.

The country’s mining sector has demonstrated a resilience in riding out a long storm of political and regulatory uncertainty, in addition to plummeting commodity prices.

The company says the strong nickel price had made it an opportune time to start drilling for the battery metal.

The premiums set by Chile's Codelco for physical delivery of copper to be paid over the LME benchmark are seen as a benchmark for global contracts.