The roof fell in on the two workers, who were installing an underground support structure at the Sojitz Gregory Crinum Mine, north of Emerald, the mining union says.

There was nothing rescuers could do for a 60-year-old worker, who died in the shaft.

His colleague, a 25-year-old man, was hit by falling rocks and spent hours trapped in the rubble. He suffered crush injuries to his legs and pelvis but will survive.

Stephen Smyth, from the CFMEU, said a third worker escaped the rockfall but suffered a medical episode after witnessing it. He was also taken to hospital.

Mr Smyth said the underground part of the coalmine had been in care and maintenance mode for a number of years, but work had recently begun to recommence production.

Preliminary information indicated the team had been sent into a drift - a near-horizontal underground passageway - to carry out repair and rehabilitation work.

"The initial information is that all three were working in the same area," Mr Smyth told AAP.

"My understanding, and it is preliminary, is that they were installing a roof support, which is a common thing, as part of an overall plan to re-establish the mine."

He said such work would have been the subject of careful risk assessment and planning work, and normally the work plan would have been reviewed by a geotechnical engineer to ensure the activity was safe.

"I'm assuming all that would have been in place," he said, adding safety arrangements will be a focus of the Mines Inspectorate and union investigations that are now underway.

Sojitz Blue chief executive officer Cameron Vorias has confirmed there was a rock fall, with activity at the accident site suspended until further notice.

Mr Smyth said he understood the three men caught up in the incident all work for Mastermyne, the contract mine operator for Sojitz.

RACQ CapRescue said the 25-year-old survivor was trapped for more than four hours as rescuers worked to pull him out.

He was flown to Rockhampton Hospital in a serious but stable condition.

Resources Minister Scott Stewart has paid tribute to the emergency services and other first responders.

"Any loss of life on our mine sites is unacceptable, and it is my expectation the Queensland Mines Inspectorate and Resources Safety and Health Queensland will investigate this incident thoroughly and with diligence," he told parliament.

"I extend my heartfelt condolences - and those of everyone in this house - to the family, friends, and co-workers of the man who has passed away, and I hope for a full and speedy recovery for the man who was injured."

Australian Associated Press