Mr McIlwain was managing director and CEO of Lafayette Mining when it established the Rapu Rapu mine in April 2005. He was then reported to have made commitments to best practices in environmental management for the mine.

However, work was suspended six months later following two cyanide-laden spills in October.

A 2008 report by Oxfam’s mining ombudsman states the discharged mine waste (tailings) contained up to 633 times the standard for cyanide set by the Philippines Department of Environment and Natural Resources (DENR) and was “high enough to cause the death of many kilograms of fish and other marine organisms”.

“The DENR later found that ‘Lafayette had wrongfully started to operate fully even before its completion of the required environmental infrastructure’,” the ombudsman’s report states.

“The company claims that one to two kilograms of thumb-sized fish and marine creatures were found after the first spill and 15 to 17kg after the second, whereas many in the community claim that the numbers of fish were much higher.”

It goes on to say Lafayette accepted responsibility for the 2005 fish kills.

On announcing his decision to step down as CEO from Unity Mining on Tuesday, Mr McIlwain told the Bay Post/Moruya Examiner he was surprised Rapu Rapu mine’s past had not come to light earlier.

He said it had not been a factor in his decision to step down at the end of the month.

“It was a long and involved… and there was no cyanide spillage,” he said.

“What happened in the Philippines was one of sabotage.

“In fact it didn’t hurt anyone and it didn’t kill any fish.”

Mr McIlwain left Lafayette in 2006 and the company was placed into administration in December 2007.