More than 30 people – mostly Liverpool Plains farmers – wielding anti-mining placards gathered at Tamworth Airport yesterday morning to call for Mr Baird’s “personal intervention” on the project.

The controversial $1 billion open-cut coalmine last week received approval from the state’s independent Planning Assessment Commission (PAC) and was referred to the federal government for a final decision.

Police officers were called to the airport about 8am and kept a close eye on the demonstrators as Mr Baird exited the plane, entered the terminal and stopped briefly to shake hands and speak to a few.

Caroona Coal Action Group chairwoman Susan Lyle presented Mr Baird with a letter on behalf of farmers, saying that in 2012-13 the Liverpool Plains accounted for $2.4 billion – or 20 per cent – of the state’s gross agricultural production value.

“It is unthinkable that any government would jeopardise our state’s and nation’s food security for the sake of one mine under any circumstances, let alone in the current climate and bleak future for coalmining globally,” the letter read. 

“The people of the Liverpool Plains want certainty and security and the protection promised by our elected representatives.”

Mr Baird told a press conference in Tamworth later in the morning that the PAC’s determination was made “at arm’s length” of government and that the process “is working”. He said the PAC had safeguarded the region’s famed black soils from mining and his government would heed the PAC’s advice to afford the plains enhanced protections.

“I understand (the farmers’) concerns,” he said. “I do not support any mining activity on the black soil of the Liverpool Plains – that is my position. We have established, very clearly, an independent process. 

“That independent process is determined by experts (and) they have determined that it should proceed.

“Obviously, not everyone is going to agree with every decision that comes out ... (but) subject to the final environmental considerations in Canberra, it is one that is proceeding.”

Shenhua Watermark, which is owned by the Chinese government, needs only federal government approval to start extracting up to 268 million tonnes of coal from deposits at Breeza, about 25km south-east of Gunnedah.

The PAC concluded the impacts on the region’s groundwater had been “comprehensively assessed” and while conceding there would “always be uncertainties” in modelling predictions, was satisfied the impact on private bores would be “minimal”.

“After seeking expert advice on the potential groundwater impacts, and as the project proposal does not intrude onto the blacksoil plains, the commission is satisfied that this mine would not preclude the continuation of significant agricultural production occurring on the blacksoil plains,” it read.