The report found damage to a hydraulic tank located under the driver's cabin caused the fire and it was not put out by the truck's automated fire suppression system because the system did not extend to that part of the truck.
The AFFF system used on the Komatsu 300 dump truck used in the mine covers major hot spots within the engine compartment, such as the turbo unit, fuel and oil lines, and the exhaust. It does not extend to the underside of the cab hydraulic componentry and therefore did not activate when the fire broke out on July 17.
The report has recommended the installation of a shield to guard the hydraulic tank and hoses on Newmont's other Waihi trucks.
A review of the fire suppression system, with possible changes to the design, has also been recommended.
A description of the event shows the driver of the truck had hauled eight loads of material to the surface before taking a one-hour lunch break at 1.30am.
After lunch, the operator made four more trips into the mine before smelling an unfamiliar burning smell as he drove up the Trio mine towards the surface.
At approximately 5.18am, the driver saw a bright spark on the right side of the engine bay and some whitish smoke.
The driver reversed the truck into a stockpile, called an emergency on the two-way radio and jumped out of the cab which had filled up with smoke.
Hitching a ride with a passing truck, the driver rode to the surface, leaving his truck to burn.
The mine was shut and all underground miners were confined to refuge chambers until they were rescued.
