As it appeared in Mining Review Africa
The need to optimise production efficiency has become a high priority for the mining industry – particularly in areas where grades are declining as ore bodies mature. Consequently, OEMs are examining their product inventories to determine how their equipment can best be improved to deliver on their clients’ needs. “Even the most commonly used tried and tested products, such as screen panels, have the potential for enhancements,” Multotec process engineer PJ Pieters tells Laura Cornish.
Pegging and blinding is one of the most common challenges in screening applications – in each and every case determined by individual ore types and processing requirements.
In response to this dilemma, raised by a prominent diamond miner, screening panel specialist Multotec has developed a new panel that effectively eliminates pegging and blinding and in doing so improves production rates. “Our client’s final recovery screening efficiency was severely impacted by this particular obstacle. We have effectively been able to resolve their issue thanks to the development of our latest panel,” Pieters reveals.
Known as the MBV panel, it was originally designed using small apertures for final diamond recovery circuits but has since then been further adapted to suit all screening applications across small and large sizes.
Unlike conventional panels, the MBV does not have a steel frame and cross-bracing which results in greater vibration and what Pieters refers to as screen deck “liveliness”.
“The screen also offers the best advantages that both screen manufacturing materials – polyurethane and rubber – have to offer. Although moulded in polyurethane, which provides an extended wear life, the screen benefits from the vibration intensity that a rubber screen delivers.
The MBV screen has been commercially available since the start of 2019 and has been successfully incorporated into diamond processing applications to date.
The locally-manufactured screen offers a variety of additional benefits Pieters explains, including ease of installation and maintenance. Because the screens fit onto a standard runner system for modular panels, only worn sections need to be changed out during maintenance periods, thus reducing operational costs.
Last, but not least, MBV’s fastening mechanism does not require the convention H-pin to install. The panels interlock on the edges, and while this speaks to installation ease as mentioned, it also enhances safety.
“The MBV screen offers the best advantages that both screen manufacturing materials – polyurethane and rubber – have to offer,” says Pieters.
Screening test rig takes risk out of process innovation
The delivery of any new product relies heavily on upfront test work to ensure its success. Through its manufacturing division, Multotec’s screening test rig helped prove the efficiency and effectiveness of the MBV panel.
“We tested our product extensively on the test rig and with this machine are able to simulate clients’ operating parameters including top size, feed rate, moisture content, screen size, aperture size, material tonnages, and so on.” Pieters outlines.
This ensures that sample sizes are representative and that the tests accurately reflect what is taking place in the mine’s processes. Tests are conducted in triplicate runs to ensure a sound scientific basis for the findings.
In the controlled environment provided by the screening test rig, customers can view the actual performance of the screen panel with material from their mining operations. Multotec’s testing protocols generate the data necessary for detailed process analysis which facilitates well-informed subsequent decisions.
The screening rig is made up of three test platforms: a vibrating screen, a sieve bend and a static drain screen platform. The vibrating screen can conduct classification tests, wet and dry dewatering tests, product development tests and plant screen simulations. The static drain screen and sieve bend screening test platforms are wet classification, drainage and dewatering tests.
“By removing the risk that mines face in trying new solutions, our testing capability smooths the way for valuable innovation to improve screening performance,” Pieters concludes.
Multotec will soon commercialise a new screen panel ideally suited to fine screening applications. Known as the FMF (fine mesh flapper) panel, it has been tested for mesh apertures ranging between 104 and 77 microns on particles with a P80 of 75 microns and has undergone four prototypes.
The need for this product has been generated by the industry’s requirement to liberate finer material that typically ends up on slimes dams.
Having extensively tested the screen, Multotec’s next step is the installation of the panel at various customer sites for final testing.