Alistair McKay of FLS talks about latest technologies and trends in minerals processing and the company’s strong drive to support sustainability by maximising yields while minimising energy and water use, waste and carbon footprints.
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FLS’s Rail-Running Conveyors offer significant operational advantages, most notably, reduced running costs.
“Our current mission is really around the sustainability of whole mineral’s processing cycles, from managing the input pressures on the crushing side, to the screening, filtration, through to the thickening and recovery of final product and all the way to tailings management and water recovery. Our strength at FLS is our ability to manage technologies across entire processing circuits through the lens of our MissionZero strategy,” begins Alistair McKay, VP for Mining Capital Sales in Europe, Arabia and Africa.
“We are always looking to reduce the carbon footprint of the solutions we offer, to minimise water and energy losses and waste. All of our R&D is about innovation so as to consume less, to ensure sustainability while improving grade recovery and extending plant life,” he adds.
At the moment, he says, FLS has a dual focus balanced between the Greenfield environment with new mines coming on stream, and the huge task of upgrading existing mines currently in operation.
Describing how this is being achieved, he begins by outlining the wear life improvements on FLS equipment. “If you are not catering for the correct wear mechanism in a chute, vibrating screen or a mill feed circuit, an entire plant can be compromised by excessive shutdowns. So, we really try and focus on how we can improve, not only on the operational reliability side, but through advanced technologies and applications at the wear contact points. This so that production can be more continuous and equipment, consumable life and periods between maintenance shutdowns are extended,” he says.
On the screening side, we've got a new NextGen range of panels for sizing crushed ore before it gets fed into grinding mills. These panels can be sized and retrofitted to any vibrating screen and the tests we have done in the iron ore sector in the Northern Cape show that the LUDODECK® NextGen polyurethane screening panels can last up to five times longer than both traditional FLS and competitor panels. This is a game changer with respect to maintenance on vibrating screens, with the aperture size being sustained for much longer, positively affecting everything downstream,” he tells MCA.
FLS’ LUDODECK® NextGen polyurethane screen media has been developed in house and, along with the vibrating screens themselves, is locally manufactured in the company’s Delmas facility. “We have just completed several significant investments there, particularly around our new vibrating screens and the large variety of NextGen screening panels.
“We are also excited by our new trommel screens, the rotating screens that fit onto the outlet end of a grinding mill. We have re-engineered a trommel solution based on lightweight tubing to significantly reduce their weight, which in turn reduces the energy consumption and carbon footprint. Together with the NexGen screen media, which is also lighter, these offer much better uptime,” he notes, adding that this also contributes towards improved sustainability of current operations and extended mine life.
Another key focus for FLS is ensuring that asset health remains optimised. “Rather than just using digitisation technologies to monitor the condition of equipment, we strive to combine the health of a machine with its production performance. As well as picking up faults, we also look to use measurements such as temperature, vibration and pressure to look at how well a machine is running: is the pump running efficiently; is the cyclone roping; is the speed of the mill causing the grinding balls to impact onto material rather than onto the liner. From the analysed data, we can make adjustments that have a direct effect on production performance and wear life,” McKay explains.
Turning to the Greenfield side of the of the business, he cites some innovations on the conveying side. “Belt conveyors have been around forever and a day, particularly long overland conveyors. We are now looking to incorporate our new Rail-Running Conveyor system to achieve significantly better efficiencies and wear life. Instead of loading all of the rom ore onto a conveyor belt running on rollers, we use rail haulage principles – a carriage supported on wheels and running on rails – to transfer the ore over long distances.
“Compared to a belt conveyor that is constantly running over rollers, we have been able to reduce ongoing transport costs by between 30% and 60%, just because of the reduced friction from a steel on steel rail application. And we are sure there are significant wear life and maintenance advantages over and above the reduced running costs,” suggests Alistair McKay, adding that towards the end of next year, FLS should have two of these systems up and running in Zimbabwe.
He says that on a long overland belt conveyor, there might be 30 000 static rollers to lubricate, inspect and replace across the length of the belt. This makes maintenance and monitoring very difficult to manage. “With the Rail-Running Conveyor, only the rail is static and all the moving parts are traveling in a loop. This makes a digital monitoring station for all the individual wheels easy to set up. What is really innovative is that the monitoring station is linked to a ‘wagon’ swap out station, where if a fault on a wheel is detected, the whole wagon can be decoupled and replaced by a new one in a matter of minutes,” he explains.
“And in terms of curvatures and inclines, the rail-based system can significantly outperform belt conveyors, enabling inclines of up to 20° to be comfortably managed. This can often reduce the number of trucks that need to be used to bring material up from a pit,” he adds.
On the milling side, he says that FLS is moving away from the traditional SAG and Ball mill combination for fine milling, which is known to be inefficient in terms of energy and water consumption. “We have introduced our new Vertical Roller Mill (VRM), which we are very excited about. We have been using VRMs for many years in the cement industry and we have one of the largest vertical roller mill in the world operating at a cement plant in Bangladesh.”
Coupled with HPGRs (high-pressure grinding rolls), VRM technology brings a new level of size classification control to a mill circuit. Successful replacements have been done, where traditional tertiary and secondary mills are removed and the ore is taken directly from a tertiary HPGR crusher into a single VRM.
Describing the difference between the FLS VRM and traditional VRM technology, he says that instead of having smooth rolls, FLS’s VRM has a carefully designed studded roll that moves over a static table – and it incorporates a dynamic air classifier that separates out the milled fines at the preset size.
“And it is not untested. It has been used in the cement industry for many, many years,” McKay adds. Finally, he cites the company’s new coarseAIR™ flotation technology, an innovative system used for the recovery of coarse particles in flotation circuits that is based on the REFLUX™ Classifiers. “Traditional flotation cells rely on rising air bubbles to float value stream material. But coarse sinking particles tend to disrupt the bubble particle interaction and impede this recovery. coarseAIR is a low turbulence, aerated fluidised bed separator combined with the lamella plate innovation used in FLS’s REFLUX™ Classifier. This technology combination is able to float larger particle sizes of up 850 µm, enabling the target grind size to be increased to deliver significant sustainability and process benefits.
“This provides excellent efficiency through improved resource utilisation – not only in terms of air, water and energy use, but of the mineral resource itself: more value is recovered, while less grinding is required.
“Using our coarseAIR is an ultimate example of an innovative sustainability solution from FLS,” concludes Alistair McKay.
