Tinkler has until next week to provide the $20 million extended guarantee for the Newcastle Knights, considered to be his second biggest passion after horse racing.

His stake in Aston is worth approximately $700 million at today’s prices but analysts believe that it would be attractive for him to sell some of his stake if Aston’s share rose above its current $10.80.

While a direct sell of his stake is one avenue, another possibility is allowing a customer to buy a share of Aston’s key asset, the $2.3 billion Maules Creek project in the Gunnedah basin of NSW.

The Maules Creek thermal and semi-soft coking coal project is targeting first coal by mid-2013 and aims to ramp up to 10.5 million tonnes per annum of product coal by 2015.

Last week Aston secured $350 million in revolving credit facilities to help provide funding for construction of Maules Creek.

The $175 million corporate loan facility and the $60 million bank guarantee facility were both co-underwritten by ANZ and Macquarie Bank.

These facilities can also be increased to create a total funding pool of $350 million under certain conditions, with the main one being state environmental approval, which Aston is hoping for by December.

Ironically, takeover activity speculation in the coal sector has been spurred by Peabody Energy and ArcelorMittal’s bid for Macarthur Coal: Tinkler sold out of Macarthur for $441 million to ArcelorMittal in 2008.

The latest proposed takeover for Macarthur Coal by Peabody Energy and ArcelorMittal bid vehicle BidCo was opportunistic, Macarthur chairman Keith DeLacy said today.

“The BidCo offer appears to be an opportunistic attempt to acquire Macarthur at a time of global economic volatility and regulatory uncertainty in Australia, and fails to reflect Macarthur’s industry leading position and the growth potential of its unique assets,” he said.

“Macarthur has a portfolio of high quality producing, development and exploration assets in the highly prospective coal basins of Queensland which are not easily replicable.

“Furthermore, with access to valuable export port capacity in an increasingly infrastructure constrained environment, Macarthur believes it is well positioned to meet its stated objective of reaching production of 9.2 million tonnes per annum by FY 2014, with significant opportunities for further growth.

“The board of Macarthur believes that there is no reason for shareholders to take any action in relation to the BidCo offer at this time.”

Some analysts believe that Bandanna Energy and Bathurst Coal could be the next takeover targets, while Whitehaven Coal, which this year failed to sell to Chinese interests, could also be re-approached if it can convince buyers that it has its Narrabri longwall commissioning under control.