As an integral part of a mine’s minerals extraction circuit, mill circuit (MC) pumps handle large rock fragments from the primary mill, which can rapidly wear the pump’s throat bush, impeller and volute liner.

Weir Minerals asserts that its Warman MC slurry pumps are able to withstand the harshest conditions while delivering their mission-critical function.

“If this installation is not optimised, the abrasion could reduce the pump’s wear life to a matter of weeks,” emphasises Weir Minerals Africa product manager for pumps Marnus 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 MC pump range is regarded as a global flagship for the mining sector and that a considerable investment is directed towards product improvement of the pumps.

“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 is designed to optimise the efficiency of the pump by 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.

“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.”

Weir Minerals has developed a range of materials for its throatbushes and for lining impellers and pump volutes and also offers various rubber compounds and a hybrid Warman MCR-M option, which is  a metal-lined volute that is interchangeable with a rubber lined volute.

The company uses three-dimensional scans of the mine environment and computational fluid dynamic analysis of the slurry flow so that performance improvements can be modelled even before installation takes place, says Koorts.