Authorities are racing to seal at least six shafts at the burning Grosvenor Coal Mine as the union warns of the the risk of another explosion.

The inferno at Queensland's largest underground coal mine, near Moranbah, is now in its third day.

Miner Anglo American has reassured the community its exclusion zone will contain any fallout in the event of a blast similar to one that happened in 2020.

Chief executive officer Dan van der Westhuizen is at the site and says the exclusion zone has been established on technical advice from the independent Australian Coal Industry Research Program.

Plumes of smoke continue to billow from the mine and a brown haze is settling over the town.

Today the streets of the normally busy community are relatively quiet as locals follow advice to stay indoors to avoid exposure to smoke.

The mine employs about 1,400 people, many of whom call the town of 10,000 home.

Mayor Kelly Vea Vea and about 70 other locals were at the town's first park run on Saturday when word of the incident started to spread.

"What happens in mining towns is news spreads like wildfire, so it didn't take long for everyone to know there was an emergency situation," she said.

Five workers suffered extensive burns after a methane explosion at the mine in May 2020 and Cr Vea Vea said people were feeling triggered by the latest incident.

She said people were also asking how it could happen again.

"There won't be a coal mine in the country who isn't wondering how this happened," Cr Vea Vea said.

'It's out of control'

Steven Smyth from the Mining and Energy Union is at the mine and says crews face a complex and difficult task working with an unstable mine atmosphere.

"It's out of control and you've just got to seal the mine to stop the oxygen into it," he said.

Anglo American, unions, mines rescue teams and RSHQ worked round the clock on the weekend to plan how to safely seal every mine opening.

A truck mounted unit powered by the engine from a MiG fighter jet is pumping nitrogen into the mine.

Mr Smyth said the structure of Grosvenor was complex and that there were about six shafts to block off, along with the main drift and conveyor belt into the mine.

He said the community was struggling after the second major incident at the mine.

"Coal communities are close-knit communities — everyone who lives in them knows risks associated with mining," Mr Smyth said.

"People are just waiting to see what's happened.

"We're blessed no-one was injured and that people could self-escape.

"Some of the guys down there are very emotional, very upset.

"Unfortunately some of them were down there the first time.

"No-one should experience it once, let alone a second time."

'Dynamic situation'

Mr van der Westhuizen said Anglo American was collaborating with Queensland Mines Rescue, Resources Safety Health Queensland and unions to get the fire under control.

"It's going to evolve over the course of the next few days, weeks and months," he said.

"The priority is to bring the mine under control and seal the mine."

He said the company was working with Department of Environment experts to monitor air quality.

"I'm so thankful for the team for evacuating the mine in an orderly way … these workers are now home with their families," Mr van der Westhuizen.

He said the incident was particularly disturbing for the long wall crew on the scene where the fire started.

Mr van der Westhuizen said there would be "a time and place" for Anglo American to turn its attention to investigating the source of the ignition.

"We're equally as interested in understanding what has gone on here so we can ensure a safe and effective mine," he said.