Adam Holland, CDE Meta, speaks with Waste Management Review about how wet processing can transform mining waste into a sustainable value-added resource.
While sustainable mining might appear like a contradiction to those in the stereotypically green resource recovery industry, it’s a movement that’s gaining global traction.
With rising demand for quality metals, in addition to increasingly stringent environmental legislation, protecting finite natural resources and extracting value from “waste” is not just environmentally sound, but good business.
For CDE Meta, the mining arm of international wet processing design and manufacturing company CDE, delivering sustainable mine operations via iron ore beneficiation is central to its “New World of Resource” purpose.
According to Adam Holland, CDE Meta Head of Business Development, with billions of tonnes of low-grade and overburden iron ore stockpiles around Australia, there is a growing appetite to invest in sustainable practices.
“CDE strives to make it as easy as possible for companies to use their waste products for the greater good, while also delivering return on investment,” Adam says.
“We’re committed to maximising product value while reducing environmental impact. Sustainability is at the heart of all CDE projects.”
CDE was recognised for its commitment earlier this year, winning two awards, one in Ireland and one in South Australia, for its Iron Baron and Iron Knob projects with SIMEC. The two awards, gained on the same day at opposite sides of world, are a testament to the global reach of the company and the strength of its sustainability driven purpose.
The awards, Adam says, highlight that while sustainable mining might not be taking over the sector just yet, solutions are available, and a return on investment is possible for resource companies interested in taking a greener approach.
The SIMEC projects, commissioned in 2017, involves two separate wet processing plants with a combined capacity to convert 17 million tonnes of historic low-grade iron ore overburden waste into a high-value product. Without processing, iron ore waste often sits in unused stockpiles.
“With a processing capacity of 950 tonnes per hour, the two plants are successfully recovering high-quality iron ore from 100-year-old-plus-low grade mining waste feed material,” Adam says.
“Our plants beneficiate iron ore waste at 42 to 53 per cent Fe content through washing and gravity separation up to 63 per cent, at an almost 50 per cent yield.”
CDE was approached by Arrium (shortly after it was acquired by SIMEC) in 2013, before signing a design and construction contract in 2016.
“Because they were dealing with a historic stockpile, and therefore variable feed, SIMEC recognised CDE’s modular approach as a differentiating factor with inbuild flexibility,” Adam says.
“SIMEC understood the inherent value of its iron ore waste but needed our assistance to develop a cost-effective beneficiation solution.”
While the plants, Iron Baron and Iron Knob, engage similar processes, Adam says the Iron Baron facility is more complex – beginning with a 42-millimetre down feed.
Each process module is spaced out and separated by conveyors and pipe runs. This, Adam says, provides operators with superior access and flexibility when maintaining the plant and allows additional processes to be added for optimisation with minimal downtime to cope with feed material that changes periodically.
The Iron Baron process begins with two L55 hoppers, each feeding 350 tonnes of material per hour. Conveyors then transfer material into CDE’s patented P2-108 double deck infinity screens which wash and split the ore between fine and course beneficiation circuits.
Following initial screening, the course fraction travels to CDE’s AggMax – a combination of a Rotomax logwasher and dewatering screen.
“This is where the ore is scrubbed to liberate any smaller particles and break off impurities,” Adam says.
“It has performed exceptionally well – running for well over a year before we had to change out the paddles.”
Once the material is cleaned and scrubbed, it travels up more conveyors for dry screening, and then enters a fine or coarse jig for gravity separation.
“The plant then separates material into three stockpiles: a course product, fine product and rejected material,” Adam says.
“Given the nature of our process, however, even the rejected material can be reclaimed, with SIMEC using it for road construction around the mine.”
Adam says attention to maximum reuse was also behind the decision to install AquaCycle thickeners at the site. The thickeners, he says, produce a sludge from the reject slimes and enable recycling of 90 per cent of process water back through the plant.”
Additional benefits of the unique CDE modular solution, Adam says, include minimal civils, a faster, safer and reduced risk installation due to factory testing and per commissioning process, as well as reduced capital and operational expenditure.
“What sets these plants apart is CDE’s ability to design a modular solution, tailored to SIMEC’s unique requirements, delivered on a turnkey basis for cost-effective operations in a mining and iron ore context. This provides a superior return on investment for SIMEC,” he says.
In addition to effective return on investment, Adam says CDE is committed to providing ongoing customer care, adding that it works with a “customer-for-life model”.
“As part of this project, CDE has also invested in a significant vendor-held spares consignment that SIMEC can draw down as and when required,” he explains.
“We also have two full-time employees who work at the site and support SIMEC through maintenance and manage the VHS consignment, ensuring that bin levels are replenished for optimal plant performance.”
Adam says he hopes CDE’s SIMEC plants serve as a case study for larger resource companies seeking to increase operational sustainability. He adds that for every tonne of ore waste processed, mining companies can significantly extend the life of their mine and maximise reserves.
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