Efficiency gainsJameson Cell drives higher recovery at Glencore’s Mount Isa mine
Jameson Cell drives higher recovery at Glencore’s Mount Isa mine
By Kylie Williams
January 14, 2019
The Jameson Cell generates a stable, fine froth and a higher-grade concentrate than other cell types, according to Glencore Technology, therefore fewer cells are required to yield the same amount of concentrate. Courtesy of Glencore Technology
The 33 conventional flotation cells in the copper concentrator cleaner circuit at Mount Isa Mines (MIM) in Queensland, Australia, posed a structural risk in their last few years of operation for Glencore. “We had little opportunity to maintain it because it was essentially a full plant shut-down to access that equipment,” explained mine manager Mark Peterson, who has worked on the MIM copper concentrator for the past 18 years.
So when it came time to replace the cells that had been operating continuously for 40 years, Glencore went with just five new cells, including three of the latest Jameson Cell models. “The Jameson Cells provided the opportunity to replace the old cells with modern technology, a smaller footprint and lower operating maintenance costs,” Peterson said.
Due to the unique way each Jameson Cell generates a stable, fine froth, it yields a higher-grade concentrate, and more of it, than other cell types. Therefore, fewer Jameson Cells are required to produce the same amount of concentrate, saving physical space.
Over the last 30 years, more than 350 Jameson Cells have been installed at operations in 30 countries. Having started out primarily for base metals and adopted early by coal operators, the Jameson Cell has since expanded to the flotation of zinc, nickel, lead, silver and platinum worldwide, and to a number of industrial and environmental applications.
Small but mighty bubbles
The Jameson Cell was originally developed in the late 1980s when MIM commissioned Professor Graeme Jameson from the University of Newcastle to develop what became known as the Jameson Cell. The key was the downcomer, said Virginia Lawson, Jameson Cell technology manager at Glencore Technology, what was once MIM Technologies and is now a Glencore-owned company. “The downcomer is a novel way of bringing together slurry and air using a plunging jet that creates its own bubbles.”
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Rather than using a stirrer to mix and inject air into the base of the flotation tank, the Jameson Cell pumps slurry through a restricted opening called the slurry lens to create a drop in pressure that draws air in from the atmosphere to mix with the slurry. The process is like water running out of a tap into the kitchen sink and producing foam at the point where the flow hits the water accumulating in the sink. In a Jameson Cell, the resulting jet produced by the downcomer generates an even mix of slurry and air contained in fine bubbles, which more effectively recovers and floats the mineral particles.
“There’s very little opportunity for particles to miss being slammed into a bubble and then recovered,” said Lawson. Recovering all the value in ore – no matter how tiny – is critical as ore grades decline and increasingly complex, fine-grained ore is sent for processing.
The Australian coal industry quickly adopted the new technology and Jameson Cells have been the main method of flotation used to separate coal during the last stage in the coal wash for the past 20 years.
“The very, very fine material that can’t be recovered through a gravity or screening system is recovered by flotation,” said Lawson. “That step was incredibly successful with the Jameson Cell able to recover fine coal very cheaply and very efficiently.”
Not so quick to catch on in Canada
Jameson Cells are now installed at over 100 coal operations in Australia and at various base and precious metal operations around the world. The cell has also been used for industrial applications, including potash processing and oil sands operations in Canada. Despite this global success, there are currently no Jameson Cells at base metal or coal operations in Canada.
“Canada has been slow to pick up on this technology,” said Lawson. “Probably because of the very first work at Kidd Creek.”
Lawson said the very first cells were not as easy to operate and that while metallurgical results have always been good, the cells at Kidd Creek in the mid-1990s did not provide the results in all of the copper roughing and copper cleaning testing situations.
Since then, even though the Mark I was a big improvement on conventional flotation, it still needed to be more robust, said Lawson.
Glencore Technology has gone through four generations of advancements in the intervening 25 years. Advancements have included widening the diameter of the downcomer, automating flow and wash water flow control, and making the downcomer easier to service. The latest iteration, the Mark IV, was introduced in 2009. The Mark V is under development and due for release in 2019.
No complaints at Mount Isa
Since commissioning in late 2015, the operation of the new circuit has improved both the grade of the concentrate and the recovery of the copper concentrator at Mount Isa. In parallel with several other process improvement initiatives, overall copper recovery has increased by 0.77 per cent since the new Jameson Cells were installed and residence time in the cleaner circuit has been reduced by 70 per cent.
“It is extremely difficult to quantify recovery improvement in this plant because there is a high degree of variability in the ore,” said Peterson. “We’ve incrementally improved our performance against model. To say that that was due to the Jameson Cell is difficult, but there are certainly stability improvements around the Jameson Cell, that’s for sure.” The Jameson Cell is designed such that an individual downcomer unit can be isolated for service or inspection without shutting the whole circuit down.
Peterson and his team used 3D modelling to arrange the new cleaner circuit, consisting of one B5400/18 Jameson Cell cleaner/scalper, one B5400/18 Jameson Cell cleaner and three cleaner/scavengers (one B5400/18 Jameson Cell and two existing 100 m3 Wemcos), before the physical installation, which took about 12 months to complete.
“In terms of commissioning, there weren’t a lot of hurdles,” said Peterson. “There were challenges in understanding the new maintenance, reagent and operational strategies, and some specific hurdles around some of the valves, but overall it’s a really simple retrofit.”
Maintenance is much easier with the new cells, said Peterson. The older cells had “hundreds” of belts and motors and barrels, whereas the new cells have no moving parts and no external air supply, which keeps maintenance simple and low cost.
Another feature that Peterson is pleased with is the scalability of the new Jameson Cell circuit. “It’s a modular system, quite compact in terms of footprint, and flexible in terms of tailoring the needs of the plant,” said Peterson.
To increase the carry capacity – how many tonnes of concentrate a cell can recover in a square metre of a surface area – of older plants, many small cells were needed to recover the required mass of concentrate.
“The Jameson Cell at Mount Isa is capable of recovering five and a half tonnes per hour per square metre of surface area,” said Lawson. “Most flotation systems are designed based on residence time. But the Jameson Cell is not residence-time dependent because it’s contact dependent. The contact is instantaneous, and that’s why it scales up directly.”
Glencore Technology sets its sights on South American copper operations
Glencore Technology currently has new Jameson Cell installations going into copper, lead and zinc operations in Africa and Mexico and are seeing interest from copper mines in South America, where molybdenum is a particular challenge.
“There are two particular benefits of [incorporating] the Jameson Cell into some copper operations,” said Lawson. “One is that they recover fine gold exceptionally well, and the other is that they recover molybdenum exceptionally well. We think the way forward in marketing the Jameson Cell is into areas where we know we can exceed the performance of other technologies.”