Capital Equipment News May 2018

MINERAL PROCESSING NEWS

Total comminution to tailings solution from Weir Minerals

Adding a partnership with technology group Andritz to its range of Trio crushing equipment, Enduron screens and other established brands, Weir Minerals Africa is further entrenching its position as a total solution provider to process plants. General Manager Comminution at Weir Minerals Africa, Vernon Steenbok, says: “Our offerings to mines now span all processes from the run-of-mine tip to the tailings dams including equipment such as crushers, conveyers, screens, feeders, pumps, cyclones, linings, hoses and valves.” Steenbok emphasises that the company has been expanding into the comminution space as a vital part of its total integrated solution provided to customers across Africa and the Middle East, from the gold mines of West and East Africa to the copper mines of Central Africa. Infrastructure development in the Middle East has also been important driver of the aggregate business, with resultant demand for Weir Minerals’ crushers and screens. As regulations governing the management of mine tailings become more onerous, the solutions available from Weir Minerals now includes a range of mechanical separation technologies such as thickeners, filter presses, centrifuges and vacuum belt filters. “To ensure the effective application The correct time to change mill liners is when the efficiency of the mill drops and not when you think the lining is completely worn. Spike Taylor, managing director of Multotec Rubber, explains that the efficiency of the mill liner relates directly to recovery efficiency of the downstream equipment, and that plant operators need to adopt a far more proactive approach in this regard. “A further ramification of waiting too long to change out the mill lining is that the fresh feed rate will decrease significantly because of the higher recirculating load, and this will have an obvious impact on production throughput in a plant,” Taylor says. One of the major costs associated with operating a minerals processing plant is the cost of power or kW.hr/t, and this is significant because when the efficiency of the closed circuit mill is reduced it means that the material is essentially being treated more than once. This is a major additional

An Enduron screen, part of a sand washing plant in a quarry application.

of our growing equipment range, we place experienced process engineers at the centre of our relationship with customers,” says Steenbok. “This is key to helping customers drive down their cost of ownership while raising efficiency, productivity and profitability.” This involves building local capacity by actively developing mineral processing and other related skills in-country, nurturing young engineers in Weir Minerals Africa’s service-centred performance culture. “Our team of process engineers brings years of experience from the mining sector, and through training and mentoring prepare the next generation of engineers cost factor, but often one that is not apparent. Sam Hearn, global sales and business development manager at Multotec Rubber, says that often when speaking to plant operators, a hurdle that needs to be jumped is the misconception that the mill liner is an expensive purchase. “Once we have engaged with the plant engineers and drawn to their attention that the liners only cost between 10 to 20% of the operating cost of a mill, and that the cost of power is far greater we have their attention,” says Hearn. Power is a monthly expenditure for a plant and in most cases is not directly allocated to the mill’s operating costs, yet power accounts for about 60% of the total operating cost for that mill. Hearn says that if it is accepted that the power cost is 60% and the liner cost is 10%, then the balance of the mill’s operating costs can be attributed to the

for their role in supporting and building a sustainable mining sector,” he says. Weir Minerals Africa’s talent pipeline includes 89 black learners – one third of them women – and this programme is set to grow to 115 learners participating in 2018. They are trained and prepared through a range of initiatives from bursary students and graduates to internships and apprenticeships. “We are here for the long haul,” says Steenbok, “and our investment in developing and acquiring leading brands, alongside our commitment to world class expertise, shows our commitment to the future of our customers and the mining industry as a whole.” b grinding media. “This is an area which can be adversely affected by liner profile and charge trajectory so Multotec takes special care to ensure the design is correct,” he explains. Worn liners allow more slippage of the charge and this results in an acceleration of the wear rate which can lead to the predicted life not being achieved with sudden replacement requirements so more frequent liner measurements need to be taken as the liners near the end of their life. Multotec Rubber has a sound reputation with its customers where the use of its MultoScan system has been implemented. Using the MultoScan measurements and the SCADA data that the company receives from customers, it is possible to generate an accurate report on the performance of the mill. This enables Multotec’s technical team to engage with the mill operator directly in terms of mill performance and costs. b

Optimising mill lining changeout gives major payback advantage

CAPITAL EQUIPMENT NEWS MAY 2018 42