Doing duty as an integral part of a mine’s minerals extraction circuit, Weir Minerals’ Warman® mill circuit (MC) slurry pumps withstand the harshest conditions while delivering their mission-critical function.
Marnus Koorts, Weir Minerals Africa’s product manager for pumps, emphasises that a mill circuit pump must deal with relatively large rock fragments from the primary mill, which can rapidly wear the pump’s throat bush, impeller and volute liner.
“If this installation is not optimised, the abrasion could reduce the pump’s wear life to a matter of weeks,” says Koorts. “The significance of wear life is high, as the whole mill circuit comes to a halt when the primary mill’s circuit pump stops – potentially affecting minerals extraction for the whole mine.”
He highlights that the company’s Warman® MC pump range is regarded as a global flagship for the mining sector, evolving over more than eight decades of continual development and innovation. A considerable portion of Weir Minerals’ total R&D investment – which sees 1,3% of its total global sales being ploughed back into product improvement – is directed toward these pumps.
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“Over the years, we have developed many unique and ground-breaking innovations,” he says. “For instance, we developed the adjustable throatbush, a technology that we have advanced ahead of our competitors.”
This innovation optimises the efficiency of the pump, ensuring that the gap between the rotating impeller and the casing is kept at the minimum specified. This, in turn, reduces recirculation and ensures that the pump’s operating efficiency is routinely restored.
The addition of deep expelling vanes on the high-pressure side of the throatbush diminishes the formation of eddies, which means less turbulence and better hydraulic efficiency. Minimising recirculation also cuts the pump motor’s energy consumption, generating savings on electricity costs that quickly justify the investment on a Warman® pump with this capability.
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“Ease of maintenance is another priority with the Warman MC pumps, allowing for quick and safe repair procedures,” he says. “The quick changeout system of the pump’s wet end is a key innovation, as the entire wet end can be unbolted and removed from the bearing and drive assembly shaft – taking hours off the time required to replace wear parts.”
With respect to the materials used, Weir Minerals has developed a wide selection of materials for its throatbushes and for lining impellers and pump volutes. While most slurry pumps on the market use high chrome metal in these applications, the company also offers various rubber compounds and a hybrid Warman® MCR-M option – a metal-lined volute which is interchangeable with a rubber lined volute.
An in-house optimisation team – using 3D scans of the mine environment and computational fluid dynamic (CFD) analysis of the slurry flow – helps customers achieve the full benefits of Warman® MC pump innovations. In this way, performance improvements can be modelled even before installation takes place, says Koorts.