In its damning “Operation Jasper” report, the Independent Commission Against Corruption also found that coal mining directors Travers Duncan, John Kinghorn, Richard Poole, John McGuigan and John Atkinson acted corruptly in securing the Mt Penny lease, which lies in the Bylong Valley near Mudgee.

ICAC has referred the case of the directors to the Department of Public Prosecutions, which may charge them for fraud offences and breaching the Corporations Act.

A spokesman for the ASX told the Sydney Morning Herald that it would closely review ICAC’s report, having raised concerns about disclosure by the relevant entities in 2011.

“The findings point to individual instances of alleged breaches rather than anything systematic,” he said.

McGuigan said in a statement: “I completely reject the findings of …[ICAC] against me…and had complied with all obligations”

Atkinson said: “I have reservations and concerns about the general process and propose to now consider the report in detail and consult my lawyers on the most appropriate action.”

Macdonald and Obeid’s cases have also been referred to the DPP, which may raise charges against them of “conspiracy to defraud”

Macdonald was found to act corruptly by ignoring department advice and creating the Mt Penny tenement to benefit the Obeid family, by providing insider information about his plans to grant an exploration lease on the property.

Obeid then negotiated a deal with the Cascade Coal directors to sell the lease for four times what he had paid.

The deal has already netted the Obeid family $30 million and it stands to make a total of $100m if it is followed through and mining on the lease begins.

The Cascade Coal directors tried to conceal the involvement of the Obeid family before trying to offload Mt Penny to publicly listed White Energy.

O’Farrell is due to make a public announcement on the ICAC findings today.

Any move to revoke the exploration licence could set a dangerous precedent in the awarding of licenses in the state, which is already under suspicion by investors because of a recent Land and Environment Court ruling that stopped the development of Rio Tinto’s Warkworth mine extension.

O’Farrell had foreshadowed in February that evidence tendered in ICAC would be considered with the development application to mine coal at Mt Penny.

NSW Greens MP John Kaye said the coal mine should not be approved because it was “officially mired in corruption”

“Approval should be withdrawn and development abandoned,” he said.