Case study on Mill Gearbox
This is a short success story about SPM monitoring at Bafokeng Rasimone underground platinum mine outside Rustenburg, South Africa.
On the 1st September 2003 a high SPM reading was noticed on the No 2 Primary Mill gearbox. The inlet bearing reading was 43 dbsv - normal is between 20 and 30 dBsv. Historical trend revealed that the high readings had started in July 2003, occurring about twice daily for about 3 hours at a time.
The supplier and expertise from a third-party company were called in to inspect the gearbox. They could not find a fault but detected an increase in vibration on the inlet bearing.
JHP thru BMG (Supplier of SPM) carried out further tests and declared the readings as a CODE D. Based on this evidence, a decision was made to change the box on 8th September.
| Unavoidable costs | |
|---|---|
| Gearbox repair | $39 000 |
| Avoided costs | |
| Casing | $32 000 |
| External open gears | $190 500 |
| Cost for replacement of gears | $95 000 |
| Indirect savings | |
| Production losses | Unknown |
| Direct Saving | |
| Cost for casing, external open gears and replacement | $278 500 |
Original presentation by Brian Hayward, Bafokeng Rasimone.