SEOUL, Dec 4 (Reuters) - South Korean steelmaker POSCO has secured exclusive negotiating rights to acquire a stake in a Canadian iron ore mine operator controlled by ArcelorMittal, a source who has knowledge of the matter said on Tuesday.

POSCO is seeking to form a consortium to buy the stake with South Korea's National Pension Service and other investors, the source said, but declined to elaborate on the size of the planned stake.

The Korea Economic Daily reported on Tuesday that POSCO has been picked as the preferred bidder for a 15 percent stake in ArcelorMittal Mines Canada, a deal expected to be worth more than $1 billion.

A POSCO spokeswoman said the company is considering a bid for a stake in the mine, but declined further comment, saying the matter is confidential.

(Reporting by Hyunjoo Jin; Editing by Edwina Gibbs) Keywords: POSCO ARCELORMITTAL/CANADA

(hyunjoo.jin@thomsonreuters.com)(82-2-3704-5685)(Reuters Messaging: hyunjoo.jin.thomsonreuters.com@reuters.net)

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