According to a report in The Sunday Times, KKR is the front-runner in the $A721 million auction of BHP’s Ekati diamond mine in Canada after Gem Diamonds and Apollo Global Management dropped out of the sales process.

The newspaper also reported Stornoway Diamond Corp and Harry Winston Diamond Corp remained in the running.

The news comes after Rio announced a review of its diamond business with a view to potentially divest four assets including the Argyle mine in Western Australia’s Kimberley region.

The review includes the consideration of a number of options for the potential sale of its diamond projects.

Rio owns 100% of Argyle, 60% of the Diavik mine in Canada and 78% of Murowa in Zimbabwe, as well as 100% of the advanced Bunder project in India.

In November last year, BHP announced a review of its own diamond business and had since sold its stake in the Chidliak project in Canada but at the time continued to review its options for the Ekati mine.

Earlier this year, KKR made investments in North American oil and gas properties after entering into a definitive agreement to acquire Barnett shale and Arkoma Basin properties from WPX Energy for around $296 million.

Shares in Rio remain unchanged at $65.95 while BHP was last trading at $34.47.