Coal mining: early detection of internal overheating during long tramming operations

During long, high‑speed tramming operations, undercarriage rollers are exposed to a high risk of overheating.
A business case from a coal mine on a 300‑ton mining excavator.

A roller was monitored with TRUST ITM® embedded sensors during real tramming operations. The system continuously recorded internal roller temperature, external temperature and machine speed.
During a 3.29 km tramming operation, the TRUST ITM® sensor detected an abnormal increase in internal temperature and triggered an alert at 90°C, while the external temperature still appeared acceptable.

In less than 30 minutes, the internal temperature reached 112°C, with an internal‑to‑external temperature delta of up to 58°C.
A second tramming event confirmed the same behaviour. Following the alert, the roller was removed and inspected to assess its real condition.

The inspection revealed internal damage despite the absence of visible external symptoms. Shaft–bushing locking, lubricant degradation and bronze transfer confirmed that critical damage was already developing internally.
By measuring temperature directly near the bushing area, TRUST ITM® embedded sensors detected internal overheating well before it became visible from the outside, demonstrating that external temperature alone is not always a reliable indicator of roller condition.