The mining giant owns 73% of Riversdale after recently acquiring Brazilian steelmaker CSN’s 19.35% stake, while India’s Tata Steel is still holding onto its 27.14% share.

Rio’s energy chief executive Doug Ritchie was appointed as Riversdale chairman on Friday. Australian coal chief operating officer Darren Yeates and energy vice president of human resources Rosemary Fagen also joined Riverdale’s board.

With Rio Australia managing director David Peever and energy chief development officer Matt Coulter already appointed, Rio has five directors on Riversdale’s nine-member board.

Significant mine and infrastructure development of Riversdale’s flagship Benga mine in Mozambique continues to make swift progress.

The open cut mine was officially opened in April 2010 and is targeting 6 million tonnes per annum of hard coking coal and 4Mtpa of export thermal coal by 2013.

Riversdale is also advancing its nearby and bigger $2 billion Zambeze hard coking coal project, which holds more than 9 billion tonnes of resources.

Last year the company started investigating the long-term possibility that Zambeze could become a 90Mtpa run-of-mine operation.

Meanwhile, Riversdale’s Zululand Anthracite Colliery in South Africa increased run-of-mine production 6.3% to 191,083 tonnes.

Rio shares are down 5c to $82.16 this morning while Riversdale shares are down 14c to $16.36.