Seven months of data from the Maules Creek monitor, which tracks the air quality of nearby mines owned by Whitehaven and Idemitsu, was analysis by Environmental Justice Australia researcher James Whelan.

Dr Whelan found days where little or no data was collected, or readings that swung from consistently negative - an impossibility - to the maximum level recommended by the government.

“The data is wildly in error, wildly inaccurate - how would anyone know if air pollution is over the standards near the Maules Creek monitor?” Dr Whelan said.

Maules Creek farmer Libby Laird said the community was crying out for independent monitoring.

“It would give the community a confidence they don't currently possess,” Ms Laird said. 

“Even to the naked eye, it is clear our air quality has been diminished.”

Dr Whelan said the companies should be forced to pay for independent EPA monitoring that was continuous and easily accessible to the public, as was the case in the Hunter Valley and elsewhere in NSW.

Pat Murphy, a farmer who lives about a kilometre from the Maules Creek mine, said it didn't matter who paid for independent monitoring so long as it was done.

“How can the community have any confidence in the monitoring?” Mr Murphy asked.

“It really highlights the shortcomings when it's left to mines to self-police.”

A Whitehaven spokesperson said the adequacy of the air-quality monitoring framework was a question for the government and regulator.

“Real time (hourly) air quality monitoring is used in some locations, but the need for such a system in the Gunnedah Basin is yet to be demonstrated,” they said.

An Idemitsu spokesperson said the Boggabri coal mine complied with its project approval conditions.