Modern Mining August 2021

SUPPLY CHAIN News

Decades of innovation elevate Warman mill circuit pumps

He highl ights 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. “Over the years, we have devel - oped 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 effi- ciency of the pump, ensuring that the gap between the rotating impeller and the cas- ing is kept at the minimum specified. This, in turn, reduces recirculation and ensures that the pump’s operating efficiency is rou- tinely 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.  The latest crane for Gamsberg Zinc will be a 20-t, double-girder electric overhead travelling crane once again of Condra design, but this time manufactured by BB Cranes at its Cape Town factory. To be delivered in September 2021, it will span 18,2-m and deliver a 12-m lifting height over a long-travel distance of 40 m. The crane will be used for maintenance and repair duties in Mota-Engil’s workshops. BB Cranes will manage manufacture, then deliver, install and commission its lat- est order as a turnkey project, supporting it with technical service and maintenance from Cape Town. The company has man- aged the lion’s share of Gamsberg Zinc’s crane maintenance requirements since the first machines were commissioned. Three to four service teams are avail- able to all BB customers, one of them on round-the-clock standby. The company employs two lifting machinery inspectors for certification. 

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 rela- tively 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 sig- nificance of wear life is high, as the whole mill circuit comes to a halt when the primary mill’s circuit pump stops – potentially affect- ing minerals extraction for the whole mine.”

The Warman mill circuit pump is designed to withstand the harshest conditions.

14 th overhead crane for Black Mountain Zinc

Cape Town lifting equipment company BB Cranes has secured an order for the 14 th overhead crane to be installed at Gamsberg Zinc Mine in Northern Cape Province.

Placed by Mota-Engil, the order is asso- ciated with a contract signed between this Portuguese mining and construction group and Black Mountain Mining for further drill- ing, excavation and transportation work at Gamsberg. Black Mountain Mining is the mine owner. The 13 cranes already installed were designed and manufactured in Johannesburg by BB’s parent company Condra. They were installed by BB Cranes. The first 11 were delivered to the mine dur- ing its initial development in 2017, and a further two units were commissioned as a separate order last year. There are currently two 10-t double- girder overhead cranes in service, one 40/8 t crane also of double-girder con- figuration, a number of 5-t single-girder machines and various hoists and lifting beams.

The 13 cranes already installed were designed and manufactured in Johannesburg by BB’s parent company, Condra.

42  MODERN MINING  August 2021