According to the state's Resources Regulator, the incident at the open cut coal mine occurred during daylight hours on a flat, dry road with clear visibility.

The truck driver was turning the vehicle from an old haul road onto a designated light vehicle road when the truck drove out onto the lower part of the windrow.

That caused it to overturn.

The driver escaped unharmed.

The regulator said vehicle operators needed to remain situationally aware when changing from one designated road type to another and always drive to the conditions.

Mine operators should also ensure there were traffic procedures around medium-sized vehicles travelling on roads that were intended for light vehicles.