Exclusive - Workers at Antamina, Peru's top copper mine, to strike -union

LIMA (Reuters) - Workers at Peru's biggest copper mine, Antamina, will begin a strike on Nov. 10 that will halt output, a union leader told Reuters on Friday.

The 1,630 unionized workers who agreed to put down their tools indefinitely are demanding a bonus to offset shrinking proceeds from a profit-sharing agreement, said Jorge Juarez, the secretary general of Antamina labor union SUTRACOMASA.

He said there are 2,860 workers in total at the mine, and that most of the unionized employees work in the mining and shipping areas.

Antamina was not immediately available for comment.

The mine produced 246,851 tonnes of copper in the first eight months of 2014, 14 percent less than in the same period a year ago.

BHP Billiton and Glencore Xstrata each have 33.75 percent stakes in Antamina. Teck owns 22.5 percent and Mitsubishi Corporation 10 percent.

Juarez said that ore grades at Antamina have slipped to about 0.8 percent of copper this year from around 1.6 percent last year.

(Reporting by Marco Aquino, writing by Mitra Taj; Editing by James Dalgleish and Gunna Dickson)