Experimental investigation of the effects of operating factors on the internal temperature of ultra-large tires using direct measurements at the Muruntau open-pit mine
This study utilizes direct internal temperature measurements on ultra-large haul truck tires at the Muruntau mine to quantify the impact of operating factors, revealing that specific conditions like high ambient heat and haul distance significantly elevate tire temperatures, and demonstrating that implementing the resulting optimization recommendations yields substantial annual economic savings.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Deep inside the massive haul trucks that move mountains of rock in open-pit mines, a silent battle is constantly being fought against heat. These vehicles, which can carry hundreds of tons of ore, rely on enormous tires to traverse rough, steep roads. While the rubber of these tires is designed to be tough, it is also a living material that reacts to stress. Every time a tire rolls, the rubber bends, stretches, and squeezes. Because rubber is not perfectly elastic, this repeated flexing traps energy inside the material and turns it into heat, a process known as hysteresis. If this heat builds up faster than the tire can release it into the air, the rubber begins to break down, leading to cracks, separation of layers, and eventually, catastrophic failure. For mine operators, a blown tire is not just a repair bill; it is a massive financial loss and a safety hazard, as these tires can cost as much as a luxury car and take hours to replace. The challenge is that the hottest part of the tire is hidden deep inside, near the steel belts that hold its shape, making it impossible to see or feel from the outside.
To solve this puzzle, researchers at the Muruntau open-pit mine in Uzbekistan decided to look directly inside the tire. Instead of relying on estimates or surface measurements, they equipped five giant haul trucks with a fleet of specialized sensors. These sensors were thin, needle-like probes that could be inserted through the thick tread of the tire until they reached the critical interface between the rubber and the steel belts. By drilling small holes into the tires and placing these probes at nine different spots across the width of the tread, the team could record the exact temperature of the rubber while the trucks were actually working. They tested the trucks under the harsh, real-world conditions of the mine, where the ground is steep, the loads are heavy, and the summer air can reach temperatures that would make most engines overheat. The goal was to understand exactly how factors like how far the truck drives, how fast it goes, how steep the road is, and how hot the air is, combine to heat up the tire from the inside out.
The results of this direct investigation revealed a clear and somewhat surprising picture of how heat behaves in these massive tires. The researchers found that the temperature is not the same everywhere on the tire. The edges, or shoulders, of the tire run significantly hotter than the center, often by several degrees. This happens because the edges endure more twisting forces when the truck turns or drives on sloped roads, and they are less able to release that heat. Furthermore, the rear tires of the truck are consistently hotter than the front ones. This is because the rear wheels carry the heaviest load, and the way the dual rear wheels are positioned traps hot air between them, preventing it from cooling down. In the scorching summer heat of the mine, where the air temperature can soar to 38°C, the internal temperature of the rear tires can climb dangerously high, sometimes exceeding 110°C, a level that threatens the structural integrity of the rubber.
The study also quantified exactly how much each driving factor contributes to this heat buildup. The team discovered that for every additional kilometer a truck travels on a haul route, the internal temperature of the tire rises by nearly 3°C. Similarly, driving faster generates more heat because the rubber is flexing more times per minute, giving it less time to cool down between cycles. Steeper roads also play a major role; as the truck climbs a steeper grade, the engine must work harder, forcing the tires to grip the ground with more force, which generates extra friction and heat. When the researchers combined all these factors into a predictive model, they found that under typical summer conditions, a one-way haul distance of just under 6 kilometers is enough to push the tire temperature to a critical limit of 105°C. Beyond this point, the risk of the tire failing increases dramatically.
This knowledge has already led to practical changes in how the mine operates. By understanding the precise relationship between the road, the speed, and the tire temperature, managers can now make smarter decisions. They can shorten haul routes on the hottest days, slow down the trucks, or even switch to a different type of tire that is specifically designed to resist higher temperatures on the most demanding routes. The implementation of these adjustments has already extended the life of the tires and saved the mine millions of dollars in operating costs. The study proves that by measuring the invisible heat deep inside the tire, rather than guessing based on surface readings, operators can keep these massive machines running safely and efficiently, turning a hidden danger into a manageable variable.
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