By DEVON MAYLIE LONDON?Rio Tinto PLC said Friday the Australian...

By DEVON MAYLIE
LONDON?Rio Tinto PLC said Friday the Australian Treasurer approved its takeover bid for Riversdale Mining Ltd., leaving the company with the task of wooing Riversdale's board to close the deal.

The Australian approval was the main regulatory hurdle the miner needed to clear its A$3.9 billion ($3.95 billion) offer for Riversdale made toward the end of last year. The miner needs to get approval from at least 50% of Riversdale's board to finalize the deal.

Support from one of the prospective coal producer's major shareholders?either India's Tata Steel Ltd. or Brazil's Cia. Siderurgica Nacional?will be key for the takeover to be approved, a person familiar with the matter said.

Riversdale has 13 billion metric tons in coking and thermal coal resources? key materials in the steel production process?in its Benga and Zambezi projects in Mozambique.

Mining analysts estimate that Mozambique will become the second-largest producer of coking coal within the next 15 years after Australia, which produces for two-thirds of all global seaborne trade of the commodity.

Earlier this month, Rio Tinto said the Riversdale board of directors recommended accepting the proposal by Rio Tinto to acquire the company for A$16 a share. Rio Tinto said all directors on Riversdale's board recommended the proposal, apart from largest shareholder Tata Steel, which abstained from voting. Tata Steel owns a 24% stake in Riversdale and said at the end of December that it's not opposed to Rio Tinto's offer.

The offer is scheduled to close Feb. 18, but could be extended, Rio Tinto said.