The tipper dolly wheel on ore hoppers is subjected to moisture and dirt. In the past two roller bearings were used for the dolly wheel.

Unfortunately the bearings tended to rust and dirt would contaminate them. This caused wear inside the bearings. The roller bearings only provided a short life and were expensive to replace, both in terms of workshop labour and new bearings.

The tipper wheel was redesigned by increasing the bore of the housing and replacing the roller bearing with a Vesconite bush.

The following advantages resulted from using Vesconite bushes:

• Tipper wheel more accurately located with less play
• Much longer life than roller bearings
• Vesconite resistant to dirt and moisture
• Cheaper than roller bearings