Union leaders couldn't be reached for comment.

"Minera Escondida is convinced the basis of this (three-year) agreement broadly exceeds the industry's conditions, ensures the stability of the business and represents benefits that will increase the quality of life for our workers and their families," the company said in a statement.

Last week, the workers voted 1,991 to one in favour of a strike to protest the company's initial contract offer.

An immediate strike was averted, however, after the mining company sought a government-mediated, five-day goodwill negotiation period, which began Monday.

If talks during the goodwill period fail, a strike would begin at the start of the first shift on Aug. 7, both the union and the company have said.

Amid a demand-driven surge in world copper prices, accidents and labour unrest have played a key role in price spikes.

Citing soaring copper prices, the miners demanded a minimum 13% wage increase, a hardship-zone wage increase and a CLP16 million net bonus. The total wage increase being sought is nearly 20%.

The company originally offered a 1.5% wage increase and a CLP4.5 million net bonus. The mining company says Escondida workers receive the highest salaries among Chilean miners.

Escondida, the world's largest privately held copper mine, produced 1.27 million metric tons of copper last year, as well as 182,000 ounces of gold.