Police were called to Curragh Coal Mine, in Central Queensland, about 3pm on Friday.
The missing worker is believed to have been inside the mine when the roof collapsed and could be trapped as deep as 1km underground.
Queensland's Acting Minister for Natural Resources and Mines Tony Perrett said emergency service and rescue crews remained on site and were doing everything possible.
He said two workers had been recovered safely following the collapse, leaving one more trapped.
"My thoughts are with all of those involved, their loved ones, the entire mining community," Mr Perrett said.
Police confirmed on Saturday morning that one of the workers had been taken to hospital with non-life-threatening injuries, while the missing man remained unaccounted for.
Curragh Coal Mine is located north of Blackwater, about 200 kilometres west of Rockhampton.
The site covers about 256 square kilometres across two separate mines, and has been in operation since 1983.
Rescue crews will continue their search operation on Saturday.
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