This project involved the provision of process control productivity improvement and optimisation services at Rio Tinto’s Paraburdoo mine site. A component of the project included works to upgrade the reclaimer cross travel system.
Cross travel seeks to control the reclaimer digging rate by traversing the face of a stockpile. During this upgrade, an opportunity arose to improve the reclaimer digging control scheme.
The existing digging control scheme adjusted the reclaimer cross travel speed, based on a theoretical stockpile model and bucket wheel current feedback loop. Large errors are introduced due to stockpile parameter assumptions of the theoretical stockpile model (stockpile height, material density, and angle of repose). This resulted in frequent over- and under- digging events causing poor reclaim efficiency and machine damage.
To overcome this, the control scheme was modified to include “stockpile memory”. This ensures historical knowledge is retained on the potential rate disturbance that lays ahead and ensures the correct speed correction early so that the disturbance to reclaim rate is reduced. The control scheme improves reclaim efficiency while minimising over digging events and allows an increase in nominal dig rate while reducing peak loads.
This control scheme is similar to the logic implemented by our team on the Parker Point slewing reclaimers.
Demonstrated productivity improvements
The project enhanced reclaimer productivity, enabling an increase in maximum digging rate and a reduction in machine damage by reducing over digging events.
To date this has resulted in an overall increase in reclaimer output of 5% for Fines and 9% for Lump product. The overall improvement resulted in a 13 minute reduction in Lump and 19 minutes in Fines for the train load times.
The project was successfully completed on schedule and budget, with an exemplary safety record.