Joyce openly criticised the federal environmental approval of the vast China Shenhua Energy-led project on his Facebook page yesterday.

“I've never supported the Shenhua mine,” he said.

“I think it is ridiculous that you would have a major mine in the midst of Australia’s best agricultural land. I've done everything in my power to try and stop the mine. We brought about further investigations. We had an independent expert scientific review.

“I feel this approval is unfortunate, but at the very least it gives the Minister for the Environment [Greg Hunt] the condition that if any of the modelling does not turn out to be factual he has the capacity to stop it at that point.”

Joyce tried to divert blame to the Labor state government that awarded the 190sq.km Watermark exploration licence to the Chinese giant for nearly $300 million in late 2008.

“The fault of this goes right back to who gave the exploration licences and why, and was further exacerbated by those who deemed it proper that it should proceed and continued on with the process,” he said.

“I think the world has gone mad when apparently you cannot build a house at Moore Creek because of White Box grassy woodlands but you can build a super mine in the middle of the Breeza plains.”

Windsor, the former National party figure-turned independent who decided to not contest his long-held federal New England seat in the 2013 election over his “poor health” has seemingly gained more spring in his step.

He told News Media that Joyce faked his disdain towards the Watermark approval.

“He’s done nothing in terms of this,” Windsor reportedly said.

“When this was all put in place, and there was funding to do this, there was a full blown bioregional assessment to look at this Liverpool Plains issue that [former environment minister] Tony Burke had put in place. Barnaby Joyce stood by and allowed that to be butchered.

“This is the classic case where Barnaby Joyce ... has been allowed to disagree with his government for localised political reasons.”

Windsor told the ABC that the Watermark approval was a strong reason to return to recontest his old seat.

"I am considering it [but] haven't made a firm decision one way or the other," he reportedly said.

"The approval of the Shenhua mine yesterday was definitely a tick in the positive box in a sense that I'd reconsider.”

However, given that Joyce won New England with a record federal election swing and a margin of 64.46% it seems likely Windsor would have faced a big voter backlash had he faced the music in 2013 – especially as the so-called conservative played a crucial role in forming the Gillard minority government in 2010.

Meanwhile, some farming interests seem ready to make fresh war cries over the Watermark approval.

“It’s been war for a long time, but now it’s really war,” Caroona Coal Action Group spokesman and farmer Tim Duddy said according to News Media.

“This community will do whatever it takes. Once the Liverpool Plains is harmed – and it will be – it will no longer be about co-existence, but sequential land use and the destruction of agriculture.”

The Watermark project still has to clear more greentape challenges with operating and management plans to be filed in the December quarter.

Federal Environment Minister Greg Hunt also said the project was still subject to 18 of the strictest conditions in Australian history.

The Watermark open cut project is targeting up to 10 million tonnes per annum run of mine over 30 years with about 84% of the saleable coal to be of a metallurgical grade.

Meanwhile, a legal challenge arguing that NSW Planning Assessment Commission approval of the project had put a local population of koalas at risk is expected to be heard in the Land and Environment Court in August.