At the end of day shift, three workers were driving back in the vehicle to a muster area.

The vehicle hit a soft spot in the haul road, causing it to slide.

As the driver tried to correct the slide, the vehicle went from a wet section of the haul road to a dry section.

The vehicle then rolled.

The NSW Resources Regulator said no workers were injured.

"When operating plant and equipment workers must remain situationally aware of the environment in which they are operating," it said.

"Mine operators should assess and demarcate any areas on roads and vehicle operating areas where conditions may pose hazards to vehicle operations."