Workers at Peru's Antamina copper mine began an indefinite strike at midnight, Monday, after they were denied bonuses and shares from a profit-sharing agreement.
Jorge Juarez, secretary general of the Antamina union, Sutracomasa, told the Reuters news agency that the stoppage would halt copper output. The mine, one of the world's largest copper sources, had been extracting around 30,000 tons per month.
Talks had been ongoing, but ended last week as no agreement had been reached.
The company running the mine had said that its profit-sharing plan has been hit by falling production and lower prices.
The Australian mining giant BHP Billiton Limited has the major 33.75 percent stake in the Antamina, which makes up almost 30 percent of Peruvian copper output.
Peru is the world's third biggest copper producer.