Posted by Paul Moore on thirtieth October 2024
On the latest AusIMM MillOps 2024 convention held in Perth from 21-23 October, a presentation by Dr David Seaman, Supervisor Metallurgy – Know-how & Innovation at Newmont, titled ‘Purple Chris Flotation Circuit Growth – From Piloting to Full Scale’ detailed how the miner to enhance the efficiency of the mill flotation circuit for extra constant metallurgical efficiency whereas making most use of scarce floorspace on the Purple Chris gold-copper mine in British Columbia, Canada.
The unique flotation circuit at Purple Chris mine included bulk rougher flotation utilizing typical tank cells, adopted by cleaner flotation consisting of two columns. Within the unique design of the cleansing circuit, the 2 columns have been operated in sequence: the focus from the primary column have been despatched to the second, smaller column to additional improve to closing concentrate-grade. As mining operations have superior, ore mineralogy has exhibited elevated variability, necessitating a extra strong cleansing circuit, particularly to accommodate greater head grades.
To deal with this requirement, a 3rd column was piloted on-site to confirm metallurgical efficiency throughout varied configuration choices. Following profitable piloting, a 3rd column was built-in into the circuit, and commissioning was accomplished in June 2021. These are Eriez Cavitation Tube Columns, chosen for piloting for his or her small lateral house requirement and plant familiarity. Newmont piloted 5 course of streams within the cleansing circuit and validated versatile cleaner circuit configuration choices to realize closing focus grade – cleaner restoration was up +0.9% for gold and +2.1% for copper with the brand new column. Complete gold and copper restoration improved by +0.5% and +0.9%.
In parallel with the cleansing circuit growth, efforts have been directed in direction of enhancing the efficiency of the rougher flotation circuit. A benchmarking train revealed the potential for improved restoration of sulphide minerals via rising rougher flotation residence time. This discovering was additional validated by the following Orebody Information (ODK) program, which confirmed enhanced restoration charges on a laboratory scale.
Along with inherent limitations in residence time, the rougher circuit usually must be reconfigured, changing the final two flotation cells from bulk rougher flotation to pyrite flotation responsibility to generate non-acid producing (NAG) tails. This reconfiguration additional reduces accessible residence time and negatively impacts rougher restoration, as evidenced by plant knowledge.
To increase residence time and alleviate capability constraints, the implementation of Eriez StackCells was explored via piloting, owing to their compact design that aligns with the accessible plant house. Primarily based on the piloting outcomes, six full-scale StackCells® have been put in as pre-roughers and commissioned in July 2022 for parallel efficiency comparisons with the plant tank cells.
As with the cleansing circuit work, plant surveys have been carried out to optimise working circumstances and make sure the advantages of those expansions, with restoration enhancements aligning with outcomes from the piloting work. Newmont states that they achieved over 3 times sooner kinetics for copper and gold flotation, with equal or greater restoration than current tank cells. Particularly, +3.5% gold and +1.9% copper with StackCells in operation. The set up was a 1:1 scale-up at optimum air, stage and impeller pace. The addition of the StackCells enhanced sulphide restoration within the rougher circuit, resulting in improved Neutralisation Potential Ratio (NPR) compliance of the rougher tails.
Newmont provides that piloting in tandem with distributors like Eriez means efficiency together with comparisons with current gear could be assessed earlier than implementation – and this venture was aided by some sharing of knowledge and outcomes from the flotation circuit at Rio Tinto’s Kennecott Copper operation.
Eriez states that StackCell flotation reduces the traditional flotation residence time requirement by 75 to 85% and will increase the selective restoration of effective particles and slow-floating minerals, which will increase profitability and improves the environmental sustainability of mining initiatives. “For mining corporations that wish to minimise the environmental impacts of flotation circuits and maximise profitability, the StackCell presents diminished flotation circuit measurement and energy consumption whereas delivering superior mineral restoration and focus grades.” It permits customers to maximise brownfield growth throughput or improve restoration at current throughput throughout the current plant footprint with cells which can be 20% of the scale of typical cells. Customers profit from recovering extra fines to pay attention that will in any other case be discarded to tailings.
