The underground explosion at a Queensland coalmine that has left five men fighting for their lives could have been far more catastrophic, a union boss says.
The miners, aged in their 40s and 50s, suffered extensive burns to their upper bodies and airways in Wednesday's blast at Anglo American's Grosvenor Coal Mine at Moranbah.
Four of the men are in a critical condition in the Royal Brisbane and Women's Hospital, with a fifth listed as stable.
CMFEU boss Steve Smyth says it's sheer luck the gas explosion wasn't as devastating as the 2010 Pike River Mine disaster in New Zealand, which killed 29 men in a series of blasts.
"Gas ignition is usually like lighting your barbeque - you light it and it goes poof. But this was like the whole barbeque exploding," he told AAP on Thursday.
"That's not very common."
"People might say we are making more of this than what it is, but this was very, very serious, as shown by the injuries of those five men."
Mr Smyth said employees had previously raised numerous concerns about the amount of gas and other work practices at the mine.
"My understanding of the concerns is that they have been raised sometimes on a shiftly, daily basis," he said.
All underground workers at the Grosvenor mine were labour hire or sub-contractors, and that compromised their ability to be vocal about safety concerns, he said.
Anglo American's Australian metallurgical coal business chief executive, Tyler Mitchelson, described the incident as devastating.
"We will work through this step by step with the authorities to understand what went wrong, drawing on the best possible expert advice," he said in a statement on Thursday.
"Our priority still remains the safety and the care of our people."
But Mr Smyth said Anglo American had the worst safety record in Queensland, with the largest number of fatalities of any operator since 2000, and the explosion had to be the result of systemic failures.
"Stop beating around the bush and bull****ting us with buzzwords. Just call it for what it is."
The Queensland government is considering establishing a board of inquiry, with public hearings, to determine what happened.
Chief Inspector of Coal Mines Peter Newman said the company "informed us that there had been an ignition of gas on the long wall face", but there was little additional information about the cause.
He said inspectors had communication with the mine last month.
Asked if any safety issues were identified, Mr Newman said: "Whenever you bring a fresh pair of eyes to an operation, there are always either recommendations for improvements in certain aspects of the mine, or at the worst case, a directive in terms of the mine taking particular action."
He did not directly answer when asked if Wednesday's incident was related to concerns previously raised with the mine.
Premier Annastacia Palaszczuk also refused to speculate on the cause.
"The mines have a duty of care to ensure their workers go to work safely and return home safely, and this has not happened in this case," she said.
"Our thoughts are with the families."
The incident comes months after a report found Queensland's mining sector was in the grips of a death cycle, with more lives at risk without a safety overhaul.
The report reviewed the 47 deaths in the state's mines and quarries from 2000 to 2019 and made a series of recommendations after finding most of the deaths were entirely preventable.
A GoFundMe page has been set up by Robin Buchanan, a colleague of the injured miners, and $25,000 has so far been raised to help the workers and their families.
"This accident has shocked us all, and this is the least we can do to assist their families," Robin said.
Australian Associated Press