Process plant optimisation is critical for any mining operation throughout its lifespan, and not only in response to mining downturn periods where efficient production becomes a greater priority.

With a solutions approach that spans the entire process value chain, Weir Minerals Africa process director JD SINGLETON shares his views with LAURA CORNISH on the importance of investing in ongoing optimisation techniques.

“Mining companies should approach process optimisation proactively and not reactively. It is typically recognised as an important activity that should be conducted during recession periods when cash is tight and the need to enhance performance increases. In these scenarios however even this type of work can be neglected due to cash constraints,” Singleton starts.

Optimisation work should be implemented continuously throughout a project’s lifecycle, regardless of economic conditions, from the project study stages, through design and commissioning – as well as on an ongoing basis during production and operation, he continues.

Optimisation work can improve projects from the start, while efforts made during commissioning can reduce or remove unexpected bottlenecks – ultimately improving production output and the bottom line.

The same principle must be applied during throughout the mine’s lifespan. “A mine’s mineralogy can change regularly over the life of mine and this can affect the performance of the process plant. Optimisation procedures can reduce this. The need for this only increases as the mine and its infrastructure ages,” Singleton states.

Weir Minerals Africa provides solutions across the entire process plant including crushing and screening, mill liners, pumps, hydrocyclones, and slurry valves.

The company assists its clients with flow sheet design and operating philosophies, helping them to change their processes to maximise their production output and component wear life.

“It’s important to recognise that optimisation work does not have to be a costly exercise,” Singleton highlights.

“The basic definition of plant optimisation is removing bottlenecks which can be done through process of elimination, evaluating each section of the plant in turn. Rerouting a conveyor or simply installing a bigger screen, changing a SAG mill to an HPGR are examples of relatively small changes to make which could result in massive production output upside.”

Most critical to achieving success however is ensuring that a mine’s design and operating philosophy is understood and well communicated between the mine owner, project house and service provider. “Our greatest achievements are always realised under these circumstances – communication is key,” Singleton notes.

With specialist optimisation teams in place for its product range within process plants, this sector of the market keeps Weir Minerals Africa busy.

“There is a lot of focus  on reducing the wear life within our hydrocyclone feed pumps, which if successful, could improve the performance of a milling circuit between 10% and 30% as a result of less downtime,” Singleton shares.

The company recently conducted a two-day site visit to a large-scale mine in the Northern Cape. With a crew comprising a process engineer, pump specialist, rubber and wear specialist and a valve specialist, the team plans to help the client improve the performance across various circuits of the plant.

“Our approach is to aim for the biggest wins that require the least capital input. The process thereafter is to execute our suggested optimisation techniques, as required by the client, during their maintenance shutdowns in order to limit the plant’s downtime. This is an essential focus for all optimisation work.”

The company also recently helped a mineral sands client to resolve an operating problem with one of their hydrocyclones. This resulted in an approval to replace all 22 hydrocyclones in the client’s circuit with Cavex hydrocyclones to ensure additional production and better classification efficiency.

In addition, the client purchased a further 20 Cavex hydrocyclones for their expansion projects based on the optimisation work that was done in the existing plant. 

Fortunately, Weir Minerals Africa has an extensive geographical footprint across Africa – with a total of 20 service centres across the continent. It is important to be situated close to the client in order to establish, build and maintain relationships, a necessity when recommending regular optimisation procedures are put in place.

This is the exact process that was undertaken for one of the company’s most recent projects – the supply of a variety of equipment ranges to a new, large-scale iron ore project in Nigeria.

The order, Singleton reveals, includes the delivery of the biggest vibrating screens ever built in South Africa – 4.3 m x 9.7 m double-deck multi-slope vibrating screens.

“Our order, which we secured only recently, also includes apron feeders, heavy duty scalping screens, jaw crushers, cone crushers, various classification screens, slurry pumps, hydrocyclones as well as a 1 200 tph HPGR (the largest in Africa), and washing equipment for two clay washing plants.

“Our agreement with the client will see full-time Weir Minerals’ employees on site, responsible for constantly monitoring and looking after our equipment.

“To ensure the plant operates at an optimal efficiency from the start, we provided a lot of optimisation work on the plant design flowsheet – in conjunction with our client’s project manager,” Singleton notes.

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“Ultimately, we are trying to educate the market on the vital importance of ongoing and continuous plant optimisation work – which has minimal impact and disruption to the operation if done on a regular basis during routine maintenance shutdown periods. A proactive approach will always deliver the best results,” Singleton concludes.

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