The excavator was being used to prepare old haul truck tyres for transport across the mine, which were being stacked in piles of three.

The excavator driver was placing a tyre on the stack when he lost control of the tyre and it slipped off the stack, making a beeline for the excavator.

The driver tried to quickly reverse away from the approaching tyre, however, it smashed into the front of the excavator cab and shattered the windscreen before coming to rest on the tracks.

The driver was uninjured.

The NSW Resources Regulator said the suitability of equipment had to be considered when planning tasks.

While the risk of an unplanned movement of the tyres was noted, work instructions did not specify how the tyres were to be stored.

With ample room available, the regulator said there was no need to stack the tyres.