Hospitals have a choice of sensitive instruments at their disposal to see deep inside our body, all without so much as lifting a scalpel.
Whether it’s an X-ray of a broken bone, or a magnetic resonance image (MRI) of your torn ligament, a simple scan can quickly and conveniently describe the landscape beneath your skin.
The same principles are increasingly being applied on a more monolithic scale, allowing mining companies to rapidly analyse and sort material dug from the planet’s crust prior to processing.
It’s no surprise that our hunger for resources is only increasing, with demand for metals like copper expected to double by mid next decade.
For elements like lithium, the anticipated surge is closer to five-fold by 2030.
New ways of harvesting power, coupled with an ever-growing market of novel digital devices, only fans the flames of competition over the raw materials for electronic components.
Meanwhile, locating easily accessible deposits of metals and minerals that are cost-effective to refine is becoming harder year by year.
Responding to declining ore grade
Scaling up with bigger machines that can move more rock is one way to overcome obstacles, but in a society increasingly conscious of its environmental responsibilities and obligation to sustainability, it’s at a cost few are willing to pay.
“For many commodities, mined ore grades are generally declining over time,” explains the Research Director of the CSIRO’s Sensing and Sorting Program, Dr David Miljak.
“That means, without productivity improvement in mining and processing, more resources such as water and energy will be required for every kilogram of metal produced.”
Ore sensing can be a valuable lever to improve mining productivity, by providing timely ore grade information to the miner or processer.
Sensing of ore isn’t exactly novel, of course. But many existing sensing methods are slow, inaccurate, or hazardous, preventing their application to sensing large volume samples in “real-time”.
The Sensing and Sorting research program has an impressive track record in developing methods of bulk analysis that are quick and accurate, enabling ore sorting or improved process control, well within the time it takes for ore to transfer from the mine to the plant.
As our dependency grows and stocks of mineral resources become ever scarcer, those sensing methods will not only need to become more sensitive, but applicable to a wider variety of materials – some we can barely even imagine needing today.
A magnetic solution
Clanking away in the confines of many hospital basements, magnetic resonance (MR) machines use powerful magnetic fields to force the protons in a human body to line up like soldiers on parade.
With a quick pulse of radio waves, the protons are set twitching against their magnetic restraints in ways that convey a thing or two about their surrounds.
The very same trick can be applied to the contents of large ore samples, providing mining operators with real-time data on material as it is being transported for refining.
“We have adopted radio spectroscopies related to MRI that are known to occur in selected crystalline materials, but that don’t need the large magnet that is required in MRI,” says Dr Miljak.
“Also, the spectroscopies we use are traditionally confined to the analysis of small laboratory samples of a few cubic centimetres. The research challenge has been to find workable approaches to scale up measurement systems to many cubic metres that can also deal with the extremely noisy electromagnetic environments that radio technology is otherwise susceptible to.”
Delivered to the market through the company NextOre, MR sensors on conveyor belts are already making a significant difference by discarding copper ore too costly to refine.
Novel MR systems for measuring ore on hauls trucks will also soon be deployed.
Future technologies for iron, lithium and other metals
Iron, too, is the focus of other new CSIRO sensing developments, providing methods for sorting or selectively mining iron ore into grades for quality control and processing. For some ores, there are precious few sensing methods available.
And it’s a shortfall Dr Miljak is keen to see filled.
“These sensing developments are also targeted at selected critical minerals, such as lithium, V-Ti [vanadium-titanium] and possibly REEs [rare earth minerals]. The same approach to developing NextOre technologies continues and the new technologies will hopefully follow in the same footsteps,” says Dr Miljak.
Lithium, a vital component in the production of batteries, is today a billion dollar market.
By the end of the decade it’s expected to exceed US$20 billion as our desire to store and carry renewable energy expands.
Metals like vanadium, tellurium, and titanium are sought for their applications in corrosion-resistant, ductile, high-strength alloys.
In decades past, demand for mineral resources was dominated to just a few parts of the periodic table.
To meet future needs we can barely even imagine today, mining will need to continue to invest in finding ways of sensing the world in a whole new light.
Dr David Miljak is presenting a talk on 'Sensing developments for preconcentration and process control applications' at WMC 2023 on Tuesday 27 June 15.30 – 17.15pm (Optimising the Production Chain session).