(Adds context, union quote, company comment)

LIMA, Nov 10 (Reuters) - Workers at Antamina, a major copper mine in Peru, said on Tuesday contract talks with the company had broken down and that they would prepare to strike.

Labor negotiations at Antamina -- a joint venture between BHP Billiton Ltd <BHP.AX> <BLT.L>, Xstrata Copper <XTA.L>, Teck Cominco Ltd <TCKb.TO> and Mitsubishi Corp <8058.T> -- are among the first to be held at a major mine since the global economic crisis hit the sector last year.

The union and the company were negotiating a new contract to replace a three-year deal that expired in late July, and industry analysts had been watching the talks closely for signs of what might happen with contract deals at other big mines.

"The general assembly has agreed to break off direct dialogue and to go on strike," union leader Francisco Marinas told Reuters, declining to say when the walkout might start.

He said three other workers assemblies, which are due to take place in the coming days, still need to approve the stoppage.

Antamina spokesman Gonzalo Quijandria said contract talks have not broken down and that he expects a response from the union on the company's latest offer.

In Chile, the world's No. 1 copper producer, recent labor negotiations at several large mines have been tough and the unrest has added to supply concerns in global markets.

Peru, a major global metals exporter, ranks No. 3 in copper production. (Reporting by Patricia Velez; Writing by Dana Ford; editing by Jim Marshall)

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