The dozer was working underneath the pre-split high wall conducting clean-up work for the face shovel. A rock fell from the high wall and hit the right-hand side of the dozer.
The impact caused damage to the electrical systems on the machine, shutting it down and disabling the radio.
The operator had to flag down a haul truck operator for assistance, Mine Safety NSW said in an alert.
"Risk assessments must be conducted establishing appropriate controls for hazards associated with highwalls before working under them," it said.
"Workers must remain vigilant and not rely on other workers' inspections when working near highwalls."
