MINING SCREENS
Furthermore , each attempt to increase the throughput in the circuit also increased the frequency of repairs .”
With a stretch target of 50,000 t / d , CMM knew that the current screen bottleneck would need to be addressed . The new SAG mill discharge screen would need to achieve a sustained capacity of 2,400 t / h , with periodic surges to 2,700 t / h . This increase in capacity represents a 30 % increase over the existing screen ’ s sustainable capacity - in the same screen footprint .
To raise operational uptime and increase average daily capacity , the Operations & Maintenance team determined that reducing downtime associated with the screen was an essential requirement . Finally , the new screen would require minimal changes to the existing support structure , saving installation time and financial resources .
“ After extensive research , CMM selected General Kinematics ’ STM-SCREEN™ , featuring Two-Mass Technology . The engineering principles behind Two-Mass Technology are inherently more suited for the rigors of heavyduty screening applications like the SAG mill discharge . The Two-Mass drive system responds to rapid increases in material loading by sustaining stroke . Whereas the brute force screen loses stroke and screening efficiency during surge conditions . Since the STM- SCREEN™ does not dampen , screening efficiency and production continue to be maintained even during surge conditions .”
General Kinematics provided a 3.6 m x 8.5 m STM-SCREEN™ for CMM ’ s application . GK designed the screen to fit the existing mounting arrangement to reduce modifications and the related downtime during the switch . The new GK STM-SCREEN™ required no significant changes to the support structure to facilitate installation . Screen cracking issues have also been eliminated ( successful operation for more than two years with no structural problems ). “ The Two-Mass drive system distributes drive forces evenly along the length and across the width of
Copper Mountain Mining successfully deployed General Kinematics ’ STM-SCREEN™ featuring Two-Mass Technology to up capacity and reduce maintenance costs the screen and , therefore , dramatically reduces concentrated forces at any point . The reduction of these concentrated forces reduces / eliminates the cracking of side structures that lead to planned and unplanned downtime as well as the related expense .”
CMM reports maintenance costs have been significantly reduced by eliminating the quarterly screen rebuild program . With zero structural failures since installation , CMM has saved an estimated $ 800,000 annually in time , material , and labour annually since installation . CMM also reports that the screen is no longer the bottleneck restricting the increased daily throughput of the mill . The successful operation of the new screen will allow CMM to increase hourly / daily tonnage to an average hourly capacity of 2,400 t / h ( including circulating load ) with surges to 2,700 t / h once the new ball mill ( BM # 3 ) comes online .
“ Screening efficiency has improved , allowing the operators to ‘ manage ’ the screen panel apertures to achieve higher recoveries throughout the overall comminution circuit , resulting in more ‘ sized ’ material reporting correctly to the ball mills . The STM- SCREEN™ will allow mill operators to increase throughput as soon as the downstream processes are expanded with the installation of BM # 3 .”
GK concludes : “ Both immediate and longterm average capacity goals have been exceeded , and the screening quality has improved due to the longer retention time of material on the screen deck . General Kinematics ’ STM- SCREEN™ retains material for approximately 26-33 seconds versus a typical brute force screen that retains material for approximately 6-8 seconds . The longer retention time allows for an optimised material separation as fines have more time to drop out . Equally as important is the ability of the STM-SCREEN™ to process at a higher bed depth without sacrificing throughput .
The STM-SCREEN™ stroke stays consistent even with large variations in the product infeed . This allows for uniform screening to always occur with no reduction in efficiency
The material spreads out evenly at the feed end , even at higher bed depths . The increased retention time of the evenly spread material allows for increased screening efficiency at the required capacities .”
Metso Outotec to provide ‘ unique ’ sustainable screening tech to iron ore project
Metso Outotec says it will supply unique sustainable screening technology for an iron ore project in the Southern Hemisphere . The order
Metso Outotec BSE Series screens are part of its Planet Positive solution
for the product screening and scalping application covers 12 Metso Outotec BSE Series™ ( Banana Screen Elliptical ) tandem screens and 4 MF Series™ screens , all equipped with 305PS screening media . In addition , the contract covers Metrics monitoring system for screens , expert support and installation services , the company says . Metso Outotec explained : “ The need to reduce water in iron ore production and other minerals processing is a critical global challenge . The innovative and patented BSE Series screens enable iron ore processing even with higher natural moisture content without adding water .”
The order value , which is not disclosed , has been booked in Minerals segment ’ s September 2021 quarter orders received . The start-up of the project is scheduled for the first half of 2024 .
30 International Mining | OCTOBER 2021