Since the Colossus of Rhodes buckled and crashed into the sea, copper has twisted and gleamed in the domed cathedrals and spires of Europe, in the Statue of Liberty green that hues the awnings and fire escapes of New York.
Beneath the buildings and the monuments, as electrification continues apace, few are confident that enough copper can be found.
“It’s a huge part of the electrification story. It’s the most-used metal in electrification, one of the best conductors of all the metals,” says Andrew Jenkin, Research Director of Mineral Resources Processing Program.
“All the electric vehicles, wind turbines, motors, all the new power cables. They’re all copper on the inside. It’s hugely important.”
Humanity will need something like three times the amount of copper we have now. It’s thought that in the next two decades, more will be needed than has been mined so far, ever.
Across the value chain, CSIRO is changing how copper is discovered, mined, sensed, sorted and processed.
Age of discovery
As copper’s moment arrives, Australia is the sixth leading global producer. Chile is comfortably first, producing more than a quarter of the world total, followed by Peru, China, the DRC and the USA.
Copper has been produced in a similar way for a long time.
It accounts for some of the world’s largest opencut mines, some of which are decades old.
Many Australians will grasp the significance of the looming shutdown of Mt Isa’s 60-year-old underground copper mines.
It’s a big, slow-moving industry that employs thousands.
Australia’s copper exploration is increasingly targeting sedimentary basins.
“One thing that’s a challenge for the exploration industry is targeting at depth because imaging geology beneath the surface across large regions is expensive," Susanne says.
“It takes more lead-up time to pinpoint where you want to focus. So the industry has to take a different approach in the way they explore compared to hard rock exploration. You need to be more strategic to reduce the search space across a region of several thousands of square kilometres, and figure out ways of lowering the cost of exploration.”
We have fine-tuned a “mineral systems approach” to find zones to search for copper.
Much of the approach is elimination. In producing simulations of ore formation and their settings, Susanne says, it’s not about finding the needle. It’s about shrinking the haystack.
“So you cross that off your map, that area, because it does not have a potential for hosting any copper,” says Susanne.
“It helps industry focus on one area and ignore the rest, because they wouldn’t have the right ingredients or there’s something crucially missing to form a deposit.”
A few miner hurdles
Copper tends to form in large ore bodies with a very low grade. That is, the amount of metal per unit rock. Copper is often about one per cent of the rock, or less. A lot of higher-grade ore bodies have been mined out.
One challenge is to find new ore bodies and more efficient ways to mine the lower-grade ore.
“We’ve been looking at caving operations, going to the bottom of a mine and creating a grid of tunnels, breaking the rock so it falls into the grid, excavating it and the large body of ore is extracted from the bottom, leaving a surface crater,” Ewan says.
“As you go deeper, mining becomes less energy efficient. You’ve got to send trucks much further. We were in a copper mine recently in NSW that was 1,600 metres deep. It’s a long way down to the bottom to get that material. Once you bring all that to the surface there’s a lot of energy required to crush and grind that rock.”
Some points of navigation for sustainable copper mining are extraction, keeping mines safe, automating and reusing them.
When you mine deep, you get rock stress. And rock bursts.
Ewan’s team is working on automated mining to avoid sending people into these highly stressed, dangerous areas.
Each part of the world has a copper character.
Africa and the US have an abundance of opencut mines.
Chile and Peru have a wealth of copper inside mountains.
In Australia, ore bodies are often covered by deep layers of sedimentary rock like sandstone and mudstone.
“A strong ore body underneath a very weak rock,” as Ewan puts it.
“It requires more work to keep the upper levels stable while you mine below them. We have been monitoring an Australian mine for how its strains and stresses evolve, using fibreoptic technologies, and adapting its computer models. This gives you a picture of what’s happening inside the rock.”
Ewan sees these advancements as progressive, in every sense.
“We need to consider the environment in a way that mining hasn’t been done previously. We need a new way of starting out mines, moving them underground to remove surface issues. We need to take away the tailings that can cause significant problems from instability and the chemicals that can leach out of them,” he says.
We can look at mining methods that have much less waste and create more of a circular economy. We can use more of what has been considered as waste for different revenue streams for the mine and the community.”
“If you can get sorting right, you can open up new deposits that would have been otherwise uneconomic,” he says.
“We view sorting as a technological lever that can make a difference into the future.”
Getting a kilogram of copper might mean grinding down a ton of rock.
If you can sort materials before they go to the plant, you flip the economics.
The ability to discard low grade rocks early in the process means a plant makes more copper for the same amount of water and power with reduced tailings, or waste streams.
Operators can apply sorting to brownfield concerns as a retrofit. A plant with inbuilt sorting needs less capital investment to make it effective. It can mean getting copper projects off the ground.
“We don’t reinvent the wheel. We develop and prototype in the laboratory trying to tweak and improve methods that have been around for a while to make them suit what we do. Our technologies are either magnetic-resonance-based or X-ray based,” David says.
“Copper is starved of sorting solutions, generally, but we have developed a new technology for bulk copper sorting."
A CSIRO spinoff company called NextOre is taking the technology to the market. There are trials overseas, and local interest. The company is built on bulk ore sorting out waste to improve ore grade.
“If you look at other industries, they sense things all the time. We’re trying to bring that element into minerals. How do we optimise production? With really good and accurate sensing,” David says.
“There’s a very long gestation period for the minerals industry to accept any technology. It can be a decade or two. Hopefully we can quicken it up.”
Trusting the process
Andrew Jenkin thinks more than the average person about chalcopyrite.
Research into the copper iron sulphide mineral has ground on in Melbourne for more than 15 years. Specifically, how to process copper from it.
“At the moment, low grade chalcopyrite is not easily leachable, but it’s a holy grail in copper,” says Andrew.
“If you could economically leach chalcopyrite, you could significantly boost copper production around the world.”
Chalcopyrite research is an example, Andrew says, of how we are prioritising projects that “really move the dial”.
In beneficiation, which involves grinding and separating minerals, our Processing Program is advancing a semi-inverted hydrocyclone technology.
“We’ve built a pilot plant in Brisbane that is about 70 per cent full scale. We are hopeful the technology will be able to significantly improve processing economics for several minerals, including copper.”
And as this article is released, Principal Research Engineer and Energy Efficiency leader David Molenaar will be unveiling another CSIRO copper processing innovation at the Hydroprocess conference in Santiago, Chile.
It’s called the Dynamic Cell Control Platform - or DC.CoP™- and is a technology to prevent electrical short-circuiting in electrolytic tank houses.
Following successful laboratory testing, the technology will be demonstrated in a commercial tank house in 2024.
If these tests succeed as expected, DC.CoP™ will markedly boost safety, production and efficiency in the copper industry.
More than a copper penny’s worth
It’s said that a US penny minted before 1982 is 95 per cent copper. This makes it worth more than triple its face value.
In an age of batteries and climate targets, that value is growing.
An electric car is made from three times as much copper as a petrol-powered car. In the face of such demand, a supply gap seems inevitable.
CSIRO is a crucial participant in the race to close it.