The challenge of cheap imports into Africa is a serious one to local South African manufacturers as a whole, mining solutions provider Weir Minerals Africa dewatering manager Ian Farquhar tells Mining Weekly.

However, the fact that Weir Minerals Africa manufactures most of its products in South Africa gives it a major advantage as it can ensure that products and parts are manufactured to specification to meet customer requirements, while supporting the local economy and the communities in which the company operates – ensuring long-term sustainability, says Farquhar.

He adds that Weir Minerals Africa is ensuring that it retains a strong client base, owing to the company’s reputation as a high-quality manufacturer and sup- plier, which offers products that are guaranteed to last. It is the company’s philosophy to be present on the doorsteps of its customers to ensure that they have access to the company’s services and support systems. The company has fully equipped, indepen- dently International Organisa- tion for Standardisation-accred- ited sales and service centres in strategic areas throughout Africa.

Multiflo Diesel Pump Units

Weir Minerals Africa’s Multiflo self-priming diesel or electric drive pontoon and skid- or trailer-mounted unit were intro- duced onto the market in 2011. These units are modular and can be engineered to suit individual applications in the toughest operating conditions, says Weir Minerals Africa rental and submersibles manager Howard Jones.

“The Multiflo range is a standard range, which can be engineered with additions to suit customers in Africa and is typically supplied with the Warman DWU dewatering pump. It can, however, be manufactured incor- porating any of the Warman pumps. The Warman DWU range produced in South Africa has a high chrome impeller and SG iron casing which can handle pressures up to 70 bar,” Jones points out.

He explains that the Multiflo unit offers solutions for specific dewatering needs rather than a one-size-fits-all approach, with fully customised options such as skid, trailer or pontoon mount and a choice of diesel engine or electric motor.

“The Multiflo unit is best suited to opencast mining oper- ations and can reach heads of 140 m without requiring staging, but can be staged in phases to reach heads, if required,” says Jones.

Farquhar explains that the Multiflo unit can be mounted on a pontoon with an additional skid-mounted Multiflo unit placed on the side of the open pit. This allows for the pump to be pontoon-mounted at stage one on the pond, with the stage two pumping operation transferring the content to its final destination.

Pump Priming

Jones says that priming a pump unit can be a frustrating activity for an operator, which is why Weir Minerals Africa has developed the automatic Vactronic vacuum priming system, which eliminates priming problems.

“When the Multiflo unit is started, the Vactronic priming system quickly lifts the water up into the priming tank. “Once the water in the priming tank makes contact with the upper probe, the drive to the vacuum pump will disengage,” says Jones, adding that, if at any time the level in the priming tank drops below the upper probe, the drive will re-engage and lift the water up again to the high probe level.

Jones notes that through this priming system, the vacuum pump life is prolonged, as it only operates when required.

Water loss shutdown is another feature of the Vactronic priming system. If there is no more water to be pumped, the level in the priming tank will fall below the lower probe and activate a six-minute timer to shut down the pump unit.