Miners back to work at Peru’s Antamina copper mine

Antamina mine.

Unionized workers at Peru’s Antamina, the country’s biggest copper producer by output, returned to work Monday morning after a four-day strike over demands for a bonus and other benefits after this year’s decline in payments from a profit-sharing program.

In a statement (available only in Spanish), operator Minera Antamina said miners resumed work Monday morning after labour authorities said the strike had been unauthorized.

The firm alleges management has been open to negotiations and urged workers to set “a transparent process of dialogue and understanding without pressure.”

This was the second time that Antamina’s workers down their tools in about a month. They also stopped working for about three weeks in November until the government declared it illegal.

The mine, located in Peru’s central Ancash region, turned out about one-third of Peru’s copper production in 2013, according to government figures. But this year hasn’t been as good: output from Jan. to Sept. this year plummeted 16.2% compared to the same time period of 2013.

Antamina, which also produces a large amount of zinc, lead, and silver, is comprised of various stakeholders. BHP Billiton (ASX:BHP) and Glencore (LON:GLEN) each have 33.75% stakes in Antamina, which has a 370,000 tons per year production capacity. Teck Resources (NYSE:TCK) holds a 22.5% stake in the mine and Mitsubishi Corporation has10%.

Minerals represent 60% of Peru’s export revenues, but lower production, falling prices and weaker demand from Asia have taken a heavy toll on earnings, dragging the nation’s growth rates down from 5.8% last year to a forecast of 3.1% for 2014, based on figures from Peru’s central bank.

Image courtesy of Minera Antamina.