When a new girth gear was urgently required at the Wiluna gold mine in WA, the mine’s new owners were confident that a segmented girth gear from SEW-EURODRIVE would fit the bill.
As this was a non-traditional girth gear design, reputations were on the line. However, with the backing of its global operation, SEW-EURODRIVE’s local team delivered in spades.
Perhaps the most unusual aspect of the SEW-EURODRIVE solution was the construction of the girth gear. Most conventional girth gears are fabricated in two parts. In contrast, the girth gears from SEW-EURODRIVE are formed from several identical segments.
This approach has a number of clear advantages. The segments are constructed from Austempered Ductile Iron (ADI), which has a higher tensile strength than the usually employed materials.
Because of this, the girth gears from SEW-EURODRIVE are thinner. Less material means less initial cost. It also means that less lubrication is required when the mill is running, therefore operating costs are reduced as well.
The major challenge for the engineering team was to design a girth gear that would precisely match the existing mounting arrangements of the mill.
Rather than relying on archival documents or approximate manual measurements, the SEW-EURODRIVE engineers chose to bring in an external contractor to take three-dimensional scans of the mill, using highly accurate laser technology.
This allowed the international team of designers from SEW-EURODRIVE to customise the new girth gear to fine tolerances.
When the time came to put this to the test, the results were outstanding. So much so, that representatives from SEW-EURODRIVE’s project engineering team, who had travelled from Perth specifically to witness the girth gear being mounted, missed out on seeing it.
Normally, girth gears need a little ‘coaxing’ to align. However, at Wiluna, the segments were assembled and mounted so quickly that it was all over before they arrived.
With Australia’s first segmented girth gear from SEW-EURODRIVE installed successfully, two more have been ordered for mines in WA and more are expected. It is clear that this alternative girth gear design is now gaining acceptance in Australia.
