LONDON, Oct 24 (Reuters) - Mining company BHP Billiton

BLT.L BHP.AX said on Thursday it was still in talks with a mining venture co-founded by the former boss of Brazil's Vale, Roger Agnelli, over the sale of BHP's slice of the Mount Nimba iron ore deposit in Guinea.

"The discussions continue," BHP CEO Andrew Mackenzie told shareholders at the group's London annual general meeting, adding Agnelli's B&A Mineracao had not yet reached a decision.

BHP selected B&A as the preferred bidder for its stake in Mount Nimba, one of the largest iron ore deposits in Guinea, last December, but at least one source familiar with the matter has since said interest on the suitor's side had cooled.

BHP, the world's largest miner, currently owns a stake of just over 40 percent in the venture behind the Mount Nimba deposit. Gold miner Newmont NEM.N owns another 40 percent.

A third party, French power plant builder Areva AREVA.PA , is currently being bought out of the venture by BHP and Newmont, leaving both with a 50 percent slice, a source familiar with the matter said recently.

BHP decided last year to pull out of its Mount Nimba iron ore project, as it reduces its presence across West African iron ore to focus on core projects.

(Reporting by Clara Ferreira Marques; editing by Sarah Young)

((sarah.young@thomsonreuters.com; +44 20 7542 1109; Reuters Messaging: sarah.young.thomsonreuters@reuters.net))

Keywords: BHP MOUNT NIMBA/