COMMINUTION AND CRUSHING
Triple the life
As mines move towards using one large scalping screen between primary and secondary crushers – rather than a modular approach using multiple smaller screens – Kwatani says it has found ways to triple the panel life in these single mission-critical units .
According to Kenny Mayhew-Ridgers , Chief Operating Officer of Kwatani , any downtime in this single-line stream would require the mine to store several hours of production . While some mines schedule regular weekly production halts during which an exciter or worn screen panels can be replaced , many operations are not so lenient , he said .
“ The message from these mines is clear : the longer the scalper can run between maintenance interventions , the better ,” Mayhew-Ridgers said . “ Our research and development efforts , together with extensive testing in the field , have allowed us to extend the life of screen panels from eight weeks to over six months .”
While smaller screens use wire mesh screening media , Kwatani has evolved larger screens that use rubber or polyurethane screen panels . Although these panels present less open area , they deliver important advantages , the company says .
“ Key to the success of our design is our integrated approach – which matches the panel design with that of the scalping screen itself ,” Mayhew-Ridgers said . “ This allows us to achieve a balance between screening area , aperture layout and screen panel life – a result based on a sound understanding of screen dynamics .”
Whereas wire mesh undergoes rapid wear from abrasive materials , the rubber or polyurethane panels are more wear resistant and deliver longer life , according to the company . The latter require gentler declines for effective stratification , but a key factor is the stiffness of the screen bed .
“ The stiffness of the supporting structure must go hand-in-hand with the screen panel design to achieve our required results ,” Mayhew- Ridgers said .
Polyurethane panels , while strong and lightweight , have screening apertures that tend to be too stiff for heavy-duty scalping applications . This leads to blinding . Rubber overcomes this problem , however , while also delivering improved wear life .
Kwatani has also developed a panel replacement system , with a fastening mechanism on the underframe , that , it says , improves safety and saves time .
footprint . The wider product portfolio enables us to offer the best suited equipment for the task considering all aspects .
“ If you look at fine grinding , for example , we take into account energy efficiency , grinding media consumption and wear life as well as overall availability .”
Hoetzel says this is also applicable to primary grinding , an area many companies have put significant effort into with the development of more powerful and larger throughput HPGRs .
“ By utilising the HRC™ ’ s ( HPGR ) benefits of reduced edge effect we can , for example , produce a smaller transfer size to the ball mills and , hence , reduce the installed power for those , shifting more comminution work to the more efficient equipment ,” Hoetzel said .
These benefits are also available to HPGR users that do not currently have an HRC in their flowsheet , as Yanata indicated .
“ Customers with existing HPGR equipment can also take advantage of the benefits of the HRC by installing our flanged roll retrofit kit with Advanced Mechanical Skew Control ,” he said . “ This performance upgrade allows their non-Metso Outotec machine to operate with all the benefits of an HRC and improve their specific throughput by up to 19 %.”
Weir Minerals Netherlands ’ Managing Director , Stuart Haydon , noting a rapid increase in the number of mining projects incorporating its Enduron
Grind down your maintenance costs
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International Mining | APRIL 2021