The dozer operator communicated with a haul truck that he was about to clean up across the face behind the truck.
The dozer operator completed one push and reversed back to start a second.
The truck operator saw the dozer reversing out of the area and assumed it had finished cleaning up.
The truck operator then reversed towards the face, narrowly missing the dozer cab with the dovetail of the truck.
The NSW Resources Regulator said the truck operator assumed the dozer was clear without waiting for positive communication from the dozer operator.
"Operators of mobile plant must establish positive communications with other plant operators before moving into impact zones," it said.
"There is no room for assumption when the consequences could be fatal.
"Mine operators should consider periodic refreshers in positive communications protocols for operators using mobile equipment."