Donald Wilson, Placer Dome Ltd.
The most significant hazard related to the maintenance of tires and wheels is the tremendous amount of energy released from a tire explosion. Standing close by is like playing Russian roulette. Statistically, twenty percent of incidents have resulted in fatalities.
While tire inflation cages are available for smaller residential or commercial tires, no such cage exists for the larger industrial tires commonly used in mines. Rather, variations of procedures typically recommended by the Society of Automotive Engineers and Occupational Health and Safety Association, et. al. are put in place…often based on old military cannon training…keep all personnel clear from the explosion trajectory.
To protect its employees, Placer Dome’s Musselwhite Mine collaborated with Wardrop Engineering to develop a tire inflation cage to accommodate the largest tire on site – a 3000 lb. 8 ft. diameter Firestone 41.25/70-39 tire used on the Caterpillar 990. At 69 psi, the energy stored in this tire is equivalent to the amount of energy required to lift a 3000 lb. car 285 ft.!
Considerable research revealed the paper “Could the World Trade Center have been modified to prevent its collapse?” by D. E. Newland and D. Cebon, which outlined the benefits of metallic foam. With high energyabsorbing properties per unit volume and its extreme light weight, aluminum foam from ERG Materials and Aerospace Corp. was eventually selected as the perfect solution to the energy-absorbing problem. It would dampen the impact energy from a tire explosion to levels below that which would cause damage to the cage’s structural members.
Armed with this energy-absorbing medium, Wardrop’s engineers were able to design a relatively traditional tire cage around the aluminum foam and the Caterpillar 990 tire. Fabrication of the cage took place at Dingwell’s Machinery in Thunder Bay and was delivered to Musselwhite Mine in the second quarter of 2005.