According to Teddy Malunga, Regional Integrated Solutions Manager at Weir Minerals Africa, mining plant performance often drops over time for various reasons. It may be that the combination of equipment is not optimal, or that the mined material being fed to the plant changes more than expected. The ad hoc replacement of individual items of equipment over the years could also lead to an imbalance in throughput capacity. All solutions, though, begin with close analysis leading to a thorough understanding of all the aspects of the circuit.
“When a client approaches us with a challenge in their circuit, we conduct a comprehensive audit in which we gather all the data we can on how the plant is currently running,” he explains. “This includes comparing its overall performance with its original design parameters.”
Where are the bottlenecks?
By analysing each stage of the processs, and each item of equipment, conclusions can be drawn about where any bottlenecks might occur. The solution that is designed should then be aimed at achieving the required key performance indicators such as throughput and target P80, while reducing downtime and raising productivity.
An important element of integrated solutions is the ability to measure where potential equipment under-performance occurs, and also to ensure optimal running conditions across the plant. Teddy points to Weir Minerals’ Synertrex intelligent platform and its ecosystem of solutions.
Tangible improvement
“Measuring wear rates, vibrations and temperatures on a pump in real time, for example, is a valuable indicator of where problems might occur,” he says. “It also creates the opportunity to monitor performance and pick up variations from the expected performance parameters.”
An integrated solution would then also be able to demonstrate a tangible and measurable improvement to the customer, he adds. Among the potential benefits that would be identified could be improvements in plant throughput, capacity, availability, efficiency or recovery – and often a combination of these.
Mill circuit
An important aspect of system optimisation is to improve energy efficiency, as mines look to reduce not only their costs but their carbon footprint. Traditional mill circuit flowsheets comprising semi autogenous grinding (SAG) mills and ball mills are inefficient, with 40 to 60% of the slurry returned to the mill for reprocessing. This recirculated load reduces the throughput and capacity of mill.
“The redesigned and reconfigured mill circuit that we envisage will see the SAG mill replaced by a more efficient HPGR, which is less energy intensive, while also reducing recirculating loads threefold,” Teddy explains. “Compared with traditional crushing and grinding methods, Enduron HPGRs can reduce energy consumption by up to 40%.”
Improving the numbers
Similarly, the development of Weir Minerals’ Cavex 2 hydrocyclones allows a 27% improvement of capacity in the latest generation design, with a reduced bypass and better cut-point. In terms of pump technology, Weir Minerals’ products improve the numbers of hours pumps can run while reducing power consumption. The Warman WRT impeller and throatbush combination, is a simple inexpensive upgrade compatible with all Warman AH, M and L Series slurry pumps.
“The aim of our integrated approach is to understand the customer’s pain points and identify ways in which we can improve their process which often leads to lower total cost of ownership,” Teddy concludes. “This leads to higher availability, throughput and profitability.”
