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Dec 16 (Reuters) – Rio Tinto Ltd said on Friday it had completed its long drawn-out acquisition of remaining 49% stake in Turquoise Hill Resources, giving the Anglo-Australian firm a 66% stake in Mongolia's Oyu Tolgoi, the world's largest known copper and gold deposit.

Turquoise Hill shareholders last week voted in favour of Rio Tinto's $3.3 billion bid to take the Canadian company private after months of back and forth.

Minority shareholders were against the deal over valuation, and no. 2 shareholder Pentwater Capital Management accused Rio of concealing delays and huge cost overruns at Oyu Tolgoi.

The larger stake in Oyu Tolgoi will help Rio Tinto compete better with BHP Group over battery metals production as the world speeds up the shift towards green economy.

BHP Group last month made a renewed $6.5 bln play for copper miner OZ Minerals, potentially allowing the miner to consolidate its copper assets in South Australia if the deal goes through.

"We now have a simpler and more efficient ownership and governance structure with our partner the Government of Mongolia, as we proceed together towards sustainable production from the underground mine," Rio Tinto's copper chief executive Bold Baatar said.

Shares of Rio Tinto finished 0.8% higher on the Australian Stock Exchange. (Reporting by Sameer Manekar in Bengaluru; Editing by Rashmi Aich and Subhranshu Sahu)