Mastermyne CEO Tony Caruso told the company's annual general meeting that the fall of ground occurred approximately 400m down the 800m long conveyor drift with the fallen ground contained to a very discrete area of the drifts.

"[It was a] tragic incident at Crinum Mine during September taking the life of a colleague and work mate," he said.

"Over the past three months we have safely remediated several similar localised falls in this area with this being the last area to be repaired."

Caruso said access to the mine's drifts was temporarily suspended pending the finalisation of investigations and completion of the safe re-entry plan.

"Overhauls and surface work is continuing while we work with authorities towards the safe re-entry of the mine," he said.

First coal production from Crimum is expected to be delayed by about 12 weeks. Nevertheless, the company is maintaining its FY2022 guidance.

Mastermyne chairman Colin Bloomfield told the annual meeting that the other major development was the company's entry into the hard rock industry through the PYBAR Mining Services acquisition.

"This is a natural step for us as most of the required competencies for success are already within our business," he said.

"Making a significant acquisition brings us the immediate scale to compete that would take years from a purely organic approach.

"The industry is reasonably consolidated and there are very few entry points. Hence, the acquisition of PYBAR Mining Services, which is a company with a similar DNA to Mastermyne being a founder led business of a similar age and size to ours.

"The combination of these businesses will provide additional scale to compete and allow us to leverage competencies from both sectors to improve all aspects of the combined entity."

Bloomfield said the inclusion of the Crinum and Cook whole-of-mine contracts and the acquisition of PYBAR would roughly triple Mastermyne's revenues in FY23 when compared to FY21.