2006 Broadmeadow Roll Over
A single vehicle accident involving a 1991 model 6 cylinder diesel engine powered Mack CHR series tanker truck, Queensland registration number 795 IKD, occurred at the lower end of the main access Ramp 1 at the intersection of Ramp 4 on the surface of the Broadmeadow Underground Mine on Monday 27th February 2006.
The vehicle was travelling down Ramp 1 that has been constructed with an approximate grade of 1:10, with a full load of water in a fibre glass tank attached to the rigid tray of the truck. The water is used to consolidate the dust around the portal entries of the underground mine.
At some undetermined point on Ramp 1, the brakes on the truck apparently failed. It has been identified through witness statements that the driver informed his rescuers the truck brakes had failed and that he had tried to shift the truck gears from second to first gear, but missed the selection.
The truck continued down the ramp, scraping along the mine services pipelines on the left side of the ramp in several places. The right-side-of-the ramp has a safety bund approximately 1m high protecting a drop of varying height into the excavation. When the truck reached the bottom of Ramp 1 grade, the driver attempted to turn the truck to the left up Ramp 4. This ramp has a formed and graded road and includes the conveyor belt to the surface stockpile area.
During the process of turning to the left, the truck tipped up onto the right side wheels, leaving the left side wheels without ground contact.
The out of control truck collided with Ramp 4 conveyor and burst into flames. Preliminary information from the Police Investigator has indicated that the fire commenced in the truck engine bay.
The position of the truck, including the fibre glass water tank up against Ramp 4 conveyor structure, had restricted egress from the truck. Mr. James climbed out of the driver's cabin, through the damaged left side passenger window and
crawled under the return belt of Ramp 4 conveyor to the opposite side away from the fire.
Recommendations
The investigation has determined that extensive brake failure on the truck has occurred due to faulty maintenance procedures. This has been compounded by the ingress of contaminants into the rear bogie brake assemblies causing the seizure of critical components and preventing them from correctly operating.
The oil leak from the front right steering axle onto the brake pads significantly contributed to the lowered braking performance of this particular wheel.
The safety sign erected at the top and bottom of Ramp 1 that specifies a speed of 30 km/h and the use of second gear is open to misinterpretation by vehicle drivers. The sign should specify either high or low range selection of the gearbox for trucks that use the ramps.
The Broadmeadow Contractor Management system appears to have not been applied rigorously as per the requirements of the Coal Mining Safety and Health Regulation 2001 s66 Braking systems.
It has been recognised throughout the investigation that the initial emergency response from Broadmeadow Mine to the Emergency Procedures relating to acknowledgement of emergency radio calls was not to a high standard and that a major review of the procedures would be required, including the response from the Control Room.
Other Information
An examination of the engine has indicated that the exhaust gas driven radial flow, engine oil lubricated turbocharger has been damaged with the front segment of the turbocharger broken off through the force of the impact when the truck hit the conveyor structure.
Adjacent to the turbo charger is the power steering fluid container. This container had the top missing and it can be reasonably suspected that the fluid ran out of the container onto the hot and damaged turbocharger and ignited.
It has been suggested that the truck engine may have continued to run for a period of time after the impact. With the truck lying on its' right side and the turbocharger damaged, engine oil that is used to lubricate the turbocharger would have continued to be sprayed onto the flames.