Fighting for better working conditions and improved pay, workers at Chile’s Escondida copper mine have gone on strike.
About 2,500 workers downed tools at the BHP Billiton operated mine when management refused to pay an annual bonus totalling about $5,000 per employee, the ABC reports.
The bonus is not covered in workers’ contracts.
Kicking off at 8am local time on Wednesday, the strike action was initially planned to last 24 hours, but organisers said it could be extended.
Union representative Marcelo Tapia said a decision on timeframes will be made in the next few hours.
"(All operations) have been halted," Tapia said.
"It's due to a variety of issues that the company has not been responding to."
Tapia added workers at BHP’s Spence and Cerro Colorado mines were also involved in the action.
BHP which has a 57.5 per cent share in the mine, the world’s largest copper producer, is yet to comment on the situation.
Fellow mining house Rio Tinto holds a 30 per cent stake in the operation.
Tapia said the bonus payments are normally at the company’s discretion.
"It now does not want to pay. We're not asking for a specific figure, but to be paid like every year," he said.
Workers’ demands also include a system to record overtime and the removal of surveillance cameras from inside mining trucks, Tapia explained.
Producing 1.1 million tonnes of copper last year, Escondida mine's 2012 earnings totalled about $AUD3.47 billion, a 14.2 percent increase from the previous year.
This is not the first strike at the operation; in 2011 union representatives staged a two-week strike, which significantly affected output.
Earlier this year employees struck a new contract agreement, which at the time eased fears of further union action at the operation.