MechChem Africa November-December 2023

Mill circuit pumps: the key to efficient operations Marnus Koorts of Weir Minerals Africa emphasises the critical importance of support levels and pump selection for mill circuit operations.

to handle.” Recognising the advantages, Weir Minerals has made substantial investments in rubber production facilities to manufacture these liners for customers. However, when applications demand it, a wide range of metal options is also avail able. Koorts says good examples would be Hyperchrome ® A61 alloy, which is particularly good for fine particle wear that is often seen between the impeller and the throat bush, and Ultrachrome ® A05 alloy which would be used for the shell as it works well with general coarse particle abrasion. “If the wear characteristics are higher than anticipated in an application, this is where the interchangeability of components plays an important role. Most of our designs allow for interchangeability between metal and rubber components based on specific wear characteristics.” Koorts also points out that, over time, changes in the slurry composition or ore grade processed by a plant can affect pump efficiency and increase wear. He says that Warman® mill circuit pumps offer standard and low flow liner capabilities, enabling operators to adjust the flow rate as needed without compromising the original installation. Retrofit optimisations are increasingly com mon as mineral processing plants evolve and seek to reduce their total cost of ownership. Weir Minerals Africa has made substantial investments in an engineering team capable of seamlessly integrating the Warman® mill cir cuit pumps into existing installations, and they work closely with engineering, procurement, construction management (EPCM) contractors, and project houses to ensure all stakeholders can make informed decisions regarding pump selection and configuration. With over 20 branches across Africa and the Middle East, Weir Minerals Africa ensures local technical support is readily available to custom ers. This proximity allows the Weir Minerals Africa teams to gain a deep understanding of each customer's operation and provide com prehensive support to ensure uninterrupted pump operation. To facilitate easy access to parts, the com pany recommends a strategic parts list and en courages customers to keep these components on-site. Critical parts are also stocked at the nearest Weir Minerals Africa branch. www.minerals.weir

arduous operating conditions on individual customer sites and need to be configured to achieve the requisite hours between scheduled maintenance shutdowns,” he says. “Close collaboration with customers and a comprehensive understanding of the plant's operating parameters are crucial to ensure the solution provided will meet the operational requirements,” he adds. One of the primary considerations when it comes to mill circuit pumps is the ability to handle large particles and high flow rates. Wear and tear in these pumps is directly proportional to the size of particles passing through, neces sitating specific construction materials and design features. Koorts says a major differentiator is that Warman ® mill circuit pumps are physically larger for the same flow rate, reducing wear by operating at lower speeds. This strategy has paid major dividends for customers and is one of the reasons for the popularity of the brand in Africa. “Another crucial aspect is the engineering of the hydraulic chamber, which enhances wear resistance and increases efficiency. This is achieved through the unique design of the vanelet, which significantly minimises unwanted turbulence and reduces both wear and energy consumption,” he explains. The reduced energy consumption not only contributes to the bottom line but also ensures a relatively short payback period on the capital investment. “Material selection for mill pumps often sparks debate, but experience in the field has shown the undeniable benefits of rubber lin ers,” Koorts says. “Rubber liners extend wear life, handle impact associated with large par ticles, and are more cost effective and easier

T he requisite levels of support are criti cal to ensure optimal performance of a mill circuit, as is the correct selection of the mill circuit pump. Attention to both these aspects will facilitate cost efficient and optimum operation of the circuit; how ever, cautions Marnus Koorts, General Manager Pump Products at Weir Minerals Africa, each is as important as the other. Weir Minerals Africa has a focus on deliver ing reliable solutions to customers that will pro vide the required performance while facilitating the lowest total cost of ownership. This, Koorts says, has seen the Warman ® mill circuit pump become the preferred choice across numerous plants in Africa. Commenting further, Koorts says that the requisite support level often requires significant investment by the pump equipment manufac turer and means having the correct parts readily available on, or close to, a customer site. This should be backed by the technical competency required to keep the pump running, he says. “A mill circuit pump is not an off-the-shelf solution. Mill circuit pumps are engineered to provide optimum performance under the The Warman mill circuit pumps reduce wear by operating at lower speed-to-flow ratios.

Weir Minerals Africa’s large branch network enables the company to deliver local services and technical support for customers.

12 ¦ MechChem Africa • November-December 2023

to