* Rio may offer around A$16 per share for Riversdale - report
* Riversdale shares in trading halt ahead of takeover announcement
* Indian consortium also eyeing possible takeover
* Hard-coking coal projects in Mozambique attractive (Releads with media report, adds fund manager quote)
By Michael Smith
SYDNEY, Dec 21 (Reuters) - Global miner Rio Tinto is talking to Australian-listed coal miner Riversdale about a higher $3.8 billion takeover bid, according to a media report, ahead of a possible bidding war for the African-focused target.
Shares in Sydney-based Riversdale, which has previously confirmed it was talking to Rio, were placed in a trading halt on Tuesday ahead of an announcement about a takeover.
Rio Tinto had formalised an offer to buy Riversdale for around A$16 per share, The Australian newspaper reported on its website. The offer, higher than A$15 per share previously on the table, would value Riversdale at $3.75 billion.
The price is a 13.5 percent premium to Riversdale's close on Dec. 3, the company's last trading price before news of Rio's interest was announced.
A Riversdale spokesman declined to comment. Rio Tinto was not immediately available to comment.
A source familiar with the situation told Reuters talks with Rio Tinto continued but declined to comment on the media report.
Investors said Rio Tinto may still have to look at a joint venture rather than a full takeover to get a deal past Riversdale's major shareholders, which include India's Tata Steel which owns about 24 percent, Brazilian steelmaker CSN and U.S. Investment firm Passport Capital.
"Rio are really long on thermal coal but short on coking coal so this would propel them into the big league over time into coking coal," said Constellation Capital Management analyst Peter Chilton.
"I think it could be some kind of joint venture or arrangement like that rather than an out-right purchase."
Riversdale has hard-coking coal projects in Mozambique that could eventually make up 5-10 percent of the global market for the key steel-making raw material.
Riversdale said earlier this month it was in talks with Rio Tinto about a takeover offer which would value the group at $3.5 billion and hinted it was also talking to other suitors.
Riversdale shares last traded at A$16.30 after rallying on news of Rio's interest.
Last week, a consortium of five state-run Indian firms, including Steel Authority of India and NTPC also said they were considering a bid for Riversdale and would make a decision by the end of the month.
Analysts have said Xstrata , Anglo-American , and Peabody Energy could also emerge as rival bidders. ($1 = 1.006 Australian Dollars) (Reporting by Michael Smith; editing by Balazs Koranyi and Lincoln Feast)