Workers at Freeport-McMoRan's Cerro Verde started an indefinite strike on Friday that halted output of about 40,000 tonnes per month at Peru's top copper mine, a union official said on Friday.
Copper prices rose following the latest disruption to global supplies, amid a monthlong strike at BHP Billiton's Escondida mine in Chile and a dispute over export rights at Freeport's Glasberg mine in Indonesia.
The 1,300 unionized workers at Cerro Verde downed tools at 7:30 a.m. (12:30 GMT), said union leader Cesar Fernandez.
According to Fernandez, the company plans to mitigate the effects of the strike using non-unionized workers. He said 300 or 400 employees at the mine do not belong to the union and do not normally work in areas key to production.
Cerro Verde and Freeport representatives did not immediately respond to requests for comment.
Three-month copper on the London Metal Exchange was up 1.2 percent at $5,760 a tonne. Prices had fallen to $5,652, their lowest since Jan. 10, in the previous session.
The Cerro Verde union initially scheduled a five-day strike but voted this week to stop work indefinitely to push for family health benefits and a bigger share of the mine's profits, Fernandez said.
Freeport-McMoRan owns a 53.56 percent stake in Cerro Verde, which more than doubled its production to nearly 500,000 tonnes of copper last year because of an expansion.
Sumitomo Metal Mining Company Ltd <5713.T> controls a 21 percent stake in the mine, and Buenaventura has 19.58 percent.
(Reporting by Marco Aquino and Mitra Taj; Editing by Lisa Von Ahn)