FLOTATION
Pilot scale NovaCell installed at a Capstone Copper operation in 2024
Capstone Copper ' s Pinto Valley mine , located in Arizona , USA , to NovaCell was investigated . The plant throughput is roughly 58 000 t / d , with a copper equivalent production of approximately 59,000 t Cu / y . The existing flotation circuit comprises both mechanical ( self-aspirating ) and column flotation cells .
Two samples were selected for the NovaCell test work . The first sample was feed ore comprising tertiary crushing circuit product ; the second sample was rougher tailings material from the existing concentrator plant . On the feed ore sample , the NovaCell demonstrated high overall copper recoveries at relatively coarse flotation feed grind sizes ( P80 ) of 480 µ m . In addition , the NovaCell recovered a significant proportion of the coarse valuable particles to the froth concentrate . On the rougher tailings sample , the NovaCell was able to recover economically significant amounts of copper and molybdenum minerals while maintaining selectivity and thereby limiting the likelihood of inefficiencies in downstream processing .
The potential impact of the NovaCell technology at the Pinto Valley mine suggested a significant increase in metal production , by approximately 15,000 t / y of equivalent copper and a 15 % reduction carbon emissions per tonne of copper equivalent . Based on the NovaCell test work results and predicted economic benefits , Capstone Copper decided to investigate the technology further with a NovaCell pilot plant at another one of its operations in the Americas , which was commissioned in September 2024 .
Other planned future work with Capstone Copper includes evaluation of a dedicated regrind and cleaner circuit for the NovaCell concentrate , instead of returning the concentrates to the ball mills ; detailed liberation
studies on NovaCell product streams , and analysis of NovaCell flotation kinetics with the aim of developing a scale-up model that does not require piloting ; and evaluation of filtration or other dewatering technology on the coarse NovaCell tailings .
Jameson Cell – adapting flotation to process difficult orebodies
The reality of the world ’ s remaining reserves is that they increasingly fall into unappealing categories . They ’ re large but lower-grade deposits that need huge tonnages processed to deliver an acceptable amount of concentrate . Or they ’ re small deposits and may have a limited life of mine .
In any of those three cases , the traditional flotation circuit is too large and expensive to economically process these deposits and the flotation circuit has to evolve . And Glencore Technology says its latest innovations are helping operations make such deposits economical to process .
The first innovation is its continuous development of the Jameson Cell into largerthroughput cells that enable a small unit to process a large tonnage . The B12000 / 24 is a single Jameson Cell able to process up to 3,200 t / h . With 24 downcomers , it ’ s been designed to be ideal for low-grade porphyry copper deposits where economies of scale are critical to unlocking a business case for the deposit .
In concept , it ’ s a simple idea . It ’ s more downcomers on a proven concept and it works .
But importantly , Glencore Technology didn ’ t just scale-up a cell to create a larger one . The new cell has eight more downcomers but only increased in diameter by 1.5m . So , in fact it ’ s smaller per unit of throughput delivered .
Senior Metallurgist - Jameson Innovation , Dr Chris Anderson , told IM : “ The feasibility of a project involving a difficult feed can live or die with the capital cost and space required to process it . So if we can significantly increase the concentrate we get per metre of footprint and per dollar of capex , then it can make the difference between a go and a no-go .”
The new cell can process a much larger volume than the previous B10500 / 16 cell and yet it ’ s 5 m lower than the previous design . It has built-in froth crowding for lower grade concentrates that might tend to have a lower mass pull . Access to the wash water trays is via the top of the cell , which makes them easier to maintain , while eliminating the need for walkways around the outside of the cell . And it ’ s designed to be safe for zones of higher seismic activity .
Other less critical features were also improved . Feedback suggested the washwater mats were hard to access and to clean as a contributor to keeping optimum performance . So the new cell replaces them with washwater trays that hinge .
“ We ’ re getting a lot of interest in the rougherscavenger duties and higher-volume applications in flotation circuits , because Jameson Cells are successfully delivering more concentrate from a smaller footprint . The Fruta del Norte operation , Prominent Hill , Ero Copper – all recent – are all rougher scalper duties of the Jameson Cell .”
Anderson said the recent installation of a single Jameson Cell ahead of a conventional flotation circuit at Ero Copper in Brazil was enough to increase throughput of the existing circuit by 50 % and deliver a grade of greater than 35 % and a recovery of greater than 70 % as the output of that single pass .
Anderson says a similar dynamic saw the Jameson Concentrator chosen for South32 ’ s Hermosa operation . “ When 10 cells can do the work of 22 but only needs 60 % of the footprint and 30 % less energy , it ’ s enabling an operation to deliver economies in a more difficult set of constraints .”
The second major innovation is in modular plants for brownfield expansions or temporary projects . “ Some mineral processing opportunities are difficult to realise . Their location is difficult , or the operation is old with minimal space for new equipment , or the feed is a small ‘ spotty ’ deposit that will only be feasible through some kind of relocatable asset ,” said Anderson .
Glencore Technology ’ s development of modular plants , he says , are a solution to this other class of emerging opportunities . A concentrator to process low volumes of less than 350 t / d are now feasible . A modular design is deemed ideal for low tonnage projects with a short life of mine but nonetheless with solid economic cases .
International Mining | OCTOBER 2024