More than 3,200 workers at Chile's huge Chuquicamata copper mine plan to go on strike this week after union-management talks broke down, state-run miner Codelco - the world's largest copper producer - said on Wednesday.
The company said in a statement it regretted the decision of the workers, who decided to reject an improved contract offer after talks aimed at averting the strike.
The company regrets the decision of the assembly. The offer made by Codelco is serious, responsible and realistic, it said.
A video circulating online shows workers at a union meeting shouting strike! strike! and voting to put down tools.
The breakdown follows two weeks of talks between management and three unions representing the workers at the sprawling mine.
Codelco producers more than a third of the world's copper.
Workers rejected as insufficient a final offer of a 1.2 per cent salary increase and a one-time benefits package worth around US$20,000.
Unions said it did not respond to workers' concerns over medical expenses and pensions.
Codelco said it made the best offer it could, given uncertainty regarding China - the world's largest copper consumer and tied up in a trade war with the US.
The strike is set to begin at the first work shift on Friday.
Located in the harsh Atacama Desert in northern Chile, the Chuquicamata deposit produces around 450,000 tons of copper a year. It is considered the world's largest open pit copper mine.
The mine is in a transition phase. After operating for more than 100 years as an open pit, in July it will shift to underground block cave mining after an investment of US$5.8 billion.