Workers at the world’s largest copper mine in Chile are embracing strike actions after pay talks with Australian resources giant BHP fell apart, casting a shadow of uncertainty over the market for the commodity.

The Escondida mine in northern Chile yearly digs up around five per cent of the world’s copper, a coveted metal used in everything from electrical wiring to rechargeable batteries.

Australian-based BHP, which owns a majority stake in the vast open-air mine, said scaled-back operations would continue as non-union staff put contingency plans into action.

Production ground to a halt at the Escondida mine when workers downed tools for 44 days in 2017, costing BHP $740 million and wiping 1.3 per cent off Chile’s annual economic output.

Encouraged by surging global prices earlier this year, union representatives have requested for a bigger slice of profits for the 2,400 workers they reportedly represent at Escondida.

The union said it launched a legal strike over unmet demands that included bigger bonuses, shorter work days, and compensation tied to total years worked at the mine.

Media reports in Chile said BHP had offered a one-off bonus of nearly $29,000, lower than the $36,000 demanded.

Nicknamed the “Big Australian”, BHP has been increasingly eager to snap up new sources of copper.