Workers started moving the EWP after finding it leaking large amounts of oil.
However, the movement caused the oil to start smoking.
Two other workers in the vicinity smelled the smoke and initiated emergency fire procedures, with all underground workers ordered to retreat to the mine's refuge chamber.
A fire crew working under breathing apparatus then moved in to check the situation but was unable to locate any fire.
It was then discovered the workers involved in moving the EWP had not informed mine control or other workers in the area, of their plans.
The NSW Resources Regulator said when the actions of workers might affect other workers, they needed to clearly communicate the task and any potential impacts.
"This is vital in underground environments where ventilation circuits, access and egress, and mine service impact can affect large numbers of workers," the regulator said.
