Astec’s high frequency screening technology is playing a role in New Caledonia’s circular economy by helping to refine and repurpose large volumes of nickel slag.
Some 1200 kilometres east of Queensland’s Sunshine Coast, New Caledonia is perhaps best known as a tropical South Pacific holiday destination. But what has kept the French island territory’s economy ticking since the mid-1800s is the nickel mining sector.
Nickel isn’t what originally took Salmon NC Chief Executive Officer Chris Salmon to New Caledonia – but it’s a big part of what kept him and his business there.
“The Salmon family has been involved in the rental and hiring of heavy mobile equipment in Australia for more than 70 years,” he says. “In 2004, we were engaged to hire out machinery for a large construction job in New Caledonia and from there, the business continued to grow. Today, Salmon NC has multiple customers across multiple sites.”
A recent project involves Chris and his team recycling nickel slag for SLN (Société Le Nickel), which operates one of the world’s largest nickel refineries in Doniambo, Noumea, on New Caledonia’s east coast. And that’s where Astec comes in.
Circular solutions
A granular sand-like material, nickel slag is a major by-product of the nickel refining process. Given New Caledonia’s more than 100-year history of nickel production – and the ongoing high production rate – SLN had been exploring ways to repurpose ever-growing stockpiles of slag in an environmentally conscious way. When SLN turned to Chris Salmon for help, he reached out to Astec – one of Australia’s leading equipment suppliers to the mining and infrastructure sectors.
“While earthmoving equipment hire has always been our bread and butter, I knew any avenue we explored for re-processing nickel slag would require specialty equipment,” Chris says, “and that’s why I contacted Astec.
“I was aware of Astec through my life in quarrying and through industry contacts. And I’d always heard them referred to as a highly reputable and reliable supplier.”
Chris says nickel slag has been widely used in New Caledonia for land reclamation.
“It contains no chemical nasties,” he says. “But SLN had the notion that it might have potential for other uses such as sand replacement in concrete, road base, fill and drainage material.”
The crucial piece of this circular economy puzzle was how to process raw stockpile to make it suitable for reuse.
Partners in processing
Astec’s Senior Account Manager, Materials Solutions – Northern Region, Shaun Quinn, travelled to New Caledonia to help scope the project.
“I went there a couple of times as Chris and I explored a range of options,” Shaun says. “And we established that Astec’s high-frequency screening technology would really suit this sort of application.”
The company purchased the Astec GT2612V and Chris says that, from the first engagement with Shaun and the Astec team, he felt very comfortable with the relationship.
“We were very confident the arrangement was going to work,” Chris says. “And we were impressed with Astec’s ability to provide the right after-sales support, too. Coming from an equipment hire background, we understand the importance of maintenance, parts support, and serviceability.
“And right from the start, Astec was fully across the complexities involved with shipping the unit from Australia to New Caledonia.”
The track-mounted high frequency screen was delivered and commissioned in November 2022 and has been processing large volumes of material since.
According to Shaun, the process involves feeding stockpiled raw nickel slag through the static grid to remove larger contaminants before it reaches the high-frequency screen, which then processes it into a usable material.
“A minus-50-millimetre material is sent to the high-frequency screen which separates anything bigger than four millimetres, and anything smaller is finished product in this application,” he says.
Shaun says the unit can be easily set up and adjusted to suit the specific needs of the project. “The high frequency screen used on this plant is a two-deck, six-foot wide, twelve-foot-long screen. As both decks are twelve foot in length, you end up with four independently adjustable six by six-foot media panels,” he says.
“Each media panel has several vibrators directly underneath, allowing you to adjust the RPM independently via flow control valves. And we can also adjust their throw, and the screen angle to ensure the material travel rate is optimised.”
This versatility came in useful early on, when the Salmon NC team discovered the nickel slag material was more abrasive than anticipated.
“This briefly caused some operational issues for us,” Chris says.
“But the Astec support team is fantastic. They helped us make tweaks and adjustments to settings and flow rates, and alter the way we were processing the material to best deal with its abrasive nature.
“Now we’re getting the best out of the machine itself, and the best operational efficiency.”
Protecting what matters
Gilles Rouvray, Salmon NC General Manager, says protecting the environment has always been a focus for the business, but diversifying into recycling has been a new challenge.
“We’re excited to make this project work and find the best possible ways to use this nickel slag product, while trying to limit our carbon footprint,” he says.
Gilles says working on a small South Pacific island with a lagoon listed on the UNESCO World Heritage List puts into perspective the need to consider the environment in how one does business.
“The factory and mine is ISO 14001 and IRMA (Initiative for Responsible Mining Assurance) certified, which is a good start when you’re doing business in the environmental world,” he says. “You need to be respectful of our planet from the start to the end.”
Chris echoes this sentiment.
“Finding a secondary use for this industrial product and genuinely contributing to a circular economy there is really satisfying. And having Astec as a partner who is equally committed to being part of that process and giving back to the environment – it’s a fantastic result all round.”
For more information, visit: www.astecindustries.com
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