Continuous improvement at Edikan (with MillROC support)

Oblokulov, Green, Van Der Spuy, Becker

Presented at the AusIMM Mill Operators Conference June 2021

ABSTRACT

One of the blessings associated with operating a modern metallurgical facility is the multitude of technologies, techniques and processes available to improve and optimise circuits. Circuit optimisation is typically an important tKPI (key performance indicator) for many metallurgical operations and its staff. Diverse process teams, often consisting of different disciplines ranging from operations experts to off-site consultants, working together to enact positive change. Underpinning this effort is the culture cultivated by management to unify the ideas and focusing the efforts toward a common goal of system improvement.

This paper provides background on the different aspects of the project, the challenges faced, the changes made and the results achieved. Specific focus is given to upgrades made to instrumentation (ieinstallation of MillSlicer), implementation of advanced process control (MillStar) and providing real time consultation and coaching (via MillROC).

The results of the project include better insights into what’s happening inside the mill, improved process stability, consistency of operation and better utilisation of mill power. Optimisation of the ball charge and steel-to-rock ratio also resulted in more efficient milling and greater throughput. Based on the actual circuit throughput trajectory before circuit optimisations, the net circuit benefit in terms of fresh feed processed was initially estimated at +8.5 percent in actual terms.

It is interesting to note that the circuit bottleneck then moved to the stockpile vibrating feeders, which were operating at maximum output, requiring physical upgrades to further de-bottleneck circuit throughput. After removal of these bottlenecks and further optimisation the circuit throughput increased to 950t/h(January 2020average) from the 814t/h average in April 2019, a further+15.8percentbenefit in average instantaneous throughput.This further benefit is attributable to a combination of MillROC consultation, improved process control, Mine-to-Mill optimisation, softer feed blends (from November 2019 onwards)and plant modifications.

All up from implementation this team ethos of optimisation in combination with state-of-the-art technology and specialist consultants has resulted in a sustainable increase of 27 percent in 8 months which will result in tens of millions of dollars in increased revenue a year at reduced operating costs, significantly improving the project economics.

Long-term benefits to liner life and media consumption are currently under investigation.Optimisation cannot be a once-off exercise; if not continuous, the results deteriorate quickly over time. The optimisation at Edikan is therefore an ongoing team effort, supported by remote data access, analysis, modelling and consultation.

ACKNOWLEDGEMENTS

The authors would like to acknowledge the operational and management team ofPerseus Mining Limitedin providing critical feedback, implementing recommendations, driving on-siteimprovements (the hard bits) and permission to publish this paper

AUTHORS

O Oblokulov1, S Green2, DVanDer Spuy3 and M Becker4

1.Processing Manager, Perseus Mining Limited, Accra Ghana. Email:This email address is being protected from spambots. You need JavaScript enabled to view it.

2.Group Operations Metallurgist, Perseus Mining Limited, Subiaco WA 6008.Email:This email address is being protected from spambots. You need JavaScript enabled to view it.

3.MAusIMM, Technical Director, Process IQPty Ltd, Balcatta WA 6021. Email:This email address is being protected from spambots. You need JavaScript enabled to view it.

4.MAusIMM, Senior Metallurgist, Orway Mineral Consultants, East Perth WA 6004.Email:This email address is being protected from spambots. You need JavaScript enabled to view it.

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