At Electra Mining Africa during September, Marnus Koorts of Weir took MechChem Africa through the advanced features of Weir’s WARMAN® large severe duty MCR® 650 slurry pump, highlighting the built-in design technology of the whole mill circuit (MC) range and the help available to mine operators in getting the best performance, uptime, flexibility and life from their mill circuits.
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Weir staff servicing a Warman MCR 400 at a copper mine.
“While there are a lot of companies that now manufacture slurry pumps, not everyone can successfully offer pumps with a discharge bigger than 350 mm. Here at Electra Mining Africa, we are showcasing our MCR 650 pump, which is specifically tailored to meeting the discharge needs of today’s very large ball- and SAG-mills, “ begins Marnus Koorts, GM for pump products at Weir in Africa. Weir, he adds, also has several of the world’s largest mill pump, the WARMAN® MCR® 760 mill circuit pump, in operation at mine sites around the world.
“The size of mills and their associated mill circuit pumps has been getting bigger and bigger in recent years,” he says.
Summarising the WARMAN® MC pump range, he says that the MCR® model is a rubber lined mill circuit pump, while the MCU® is an unlined pump made from high-chrome white iron. “The rubber liners in our MCR pumps can be swapped with metal liners, which is what we denote as our MCR-M pumps. This gives us another level of flexibility when it comes to meeting the specific needs of a particular mining operation and ore body,” Marnus Koorts tells MechChem Africa.
Pointing towards the MCR® 650 pump on show, he says that these weigh 40 t. “If for any reason, the lining material needs to be changed, it’s a huge job to move a pump of that size,” he notes. He adds that Weir has the widest range of metal and rubber lining materials, even for very large pumps such as these. “On the MCR-M pump, we have the flexibility to change the material from one of our rubber compositions to any one of our metal compositions, and we can even make the throatbush, the impeller and volute liners from different materials so as to optimise the wear life in different parts of a pump,” he informs MechChem Africa.
“Optimising the wear linings of one of these severe duty large pumps is much more complex than people think. A rubber liner might work quite nicely at first, but after time might need to be changed.”
“We have developed advanced elastomer (rubber) technologies and hypereutectic alloy (metal) technologies that allow us to offer the largest range of material options and combinations. Using wear evaluation software, we have also come up with unique designs that deliver superior reliability, performance and wear life,” he assures.
Simplifying the on-site changing of a pump’s liners to a preferred combination, Weir’s design of the WARMAN® MC range enables the whole of the clam shell – with all of the wet-end components, including the liners and impeller – to be removed without opening the pump case. “At the mine, we remove the entire clam shell, and immediately drop in a new one with a new set of liners and components. We then take the worn pump clam shell to our shop and within a few weeks, we refurbish it under tightly controlled conditions.
“This requires intricate work and the individual impellers, liners and other components are very heavy. By doing it at our facility, a mine sees only a rapid swap out that both minimises downtime and ensures that the refurbishment is done to OEM standards,” he says, adding that this approach is now standard on all WARMAN® MC pumps of this size.
Advanced features of the WARMAN® MCR® pump
Moving over to the WARMAN® MCR® pump on display, Marnus Koorts starts to outline some of the innovative features of this giant pump. “Our designs are based on more than 100 years of fundamental and applied research, which continues to include many wear performance field trials,” he says.
“Slight changes in the shape can be seen as small details, but compared to simpler impeller designs, they make a huge difference, in terms of both efficiency and wear life,” Marnus Koorts tells MechChem Africa. “While most severe duty impellers are designed to be bigger and heavier to extend their wear life, ours incorporate a host of subtle flow enhancement features that have a significant effect on performance, reliability and life,” he adds.
NEXT intelligent solution for optimising processing circuits
Weir’s NEXT Intelligent Solutions cut across all of the company’s processing equipment, optimising performance, tracking wear and monitoring machine health. “On our large pumps we use vibration sensors on the outside of the pump casing to measure the vibrations inside of the pump, temperature sensors for the bearing assemblies, and we continuously monitor the electrical parameters on the pump motor, for example,” continues Koorts.
All this data, he says can be analysed and used to determine exactly how efficiently the pump is running; how worn the impeller or the liner is; and when it makes the most sense to intervene.
When an issue is identified, Weir’s NEXT monitoring system can help operators to predict the potential consequences, how long the pump can continue to run safely, what is likely to fail and the extent of the resulting damage. “It may be possible to continue to run the plant until a scheduled shutdown, production might need to be trimmed back a little until a pump can be repaired, or if the problem is more serious, the need for an unscheduled shutdown can be properly justified and managed,” he explains, adding that NEXT solutions identify risks so that managers can take in-time decisions to protect their assets.
Properly tracking the wear life of liners can save operators a huge amount of money, he says. “A set of spares for one of our severe duty large pumps can cost a significant amount. A NEXT service contract is negligible compared to the risk of causing irreparable damage to the pump, it can also maximise the life of these spares, saving a fortune on unnecessary replacements.
“And a catastrophic breakdown on some of these critical pumps can stop the entire site, which makes the risk of not knowing what is happening inside their mill circuit pumps way too high,” he argues.
“Our WARMAN MCR 650 slurry pump is a benchmark mill circuit pump that not only offers best performance, uptime, flexibility and wear life, it also delivers high energy efficiency and lower costs of ownership, making it a flagship technology for sustainable mining,” concludes Marnus Koorts.
