Senior officials from Aluminum Corp. of China, or Chinalco, downplayed speculation Thursday that the state-owned metals producer is pursuing talks with Rio Tinto Ltd. (RIO.AU) on a joint investment in Mongolia's copper and gold Oyu Tolgoi mine, but stopped short of ruling out the possibility.

"I'm not sure, but probably not," said Wang Wenfu, president of Chinalco Overseas Holdings, the company's foreign investment arm, when asked if the pair had begun cooperation talks.

Lu Youqing, Chinalco's vice president, said he was uncertain on the issue.

Australian media reported Thursday that Rio Tinto has begun talks with Chinalco on possible cooperation at the $4 billion Oyu Tolgoi mine.

Rio Tinto and its joint venture partner in Oyu Tolgoi, Ivanhoe Mines Ltd. (IVN), signed an investment agreement with the Mongolian government earlier this month and plan to produce 450,000 tons of copper and 300,000 ounces of gold a year from the mine.

Officials from Rio Tinto and Ivanhoe declined to comment.

-By Chuin-Wei Yap, Dow Jones Newswires; 8610 8400 7704; chuin-wei.yap@dowjones.com