The Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) is part of the Australian Government’s Cooperative Research Centre (CRC) Program. It is co-funded by seven mining majors - Anglo American, AngloGold Ashanti, BHP, Glencore, Newcrest, Teck and Sumitomo. It also includes the support of ten research institutions and seven major METS - Metso, Orica, Hatch, Imdex, Sodern, JKTech and METS Ignited.
Originally established in 2010, CRC ORE is a not for profit co-creation partnership, which received its second phase of funding in 2015 (A$34 million from the Australian Government and the remainder from its partners, mostly the miners). It is focused on “improving the productivity, energy and water signatures of mining operations”.
Chief Executive Officer Dr Ben Adair notes: “To meet our Commonwealth funding requirements, we had to raise some A$114 million over our six-year term. With 18 months left and we will have raised in excess of A$160 million – a consequence of the traction and support we’ve gained, from our mining company sponsors in particular.”
“We are seen as independent, trusted advisors by the Mining companies, to the point that we are now often used to manage their site-based gangue rejection strategies on their behalf.”
Optimising Resource Extraction
Dr Adair explains that CRC ORE’s commitment to optimising resource extraction (ORE) is underpinned by two suites of technologies: Grade Engineering® and the Integrated Extraction Simulator (IES). The former focuses on extracting metal more efficiently by separating ore from waste before it enters comminution. The latter is a cloud-based simulation and optimisation platform across the mine to mill value chain. Grade Engineering therefore involves the implementation of practical gangue rejection technologies at production scale on sites. IES provides the opportunity to optimise downstream processing performance from this newly engineered feedstock.
Dr Adair urges that, to reduce the mining industry’s energy and water footprints, it’s important to take a “helicopter view” of where the sector is today.
“We get delusional about the current status quo,” he says. “The fact is that for base and precious metal operations, we still mine huge volumes of rock and send it into a process plant where 99% or more of this material has no value whatsoever. Further, the comminution process used on this material is in itself less than 10% energy efficient in breaking rocks and collectively consumes 3% of the worlds’ electricity – enough to keep the lights on in Germany each year!”
Dr Adair adds: “We also over-grind the material to extract the target minerals, way beyond what is necessary to efficiently separate and recover the metal. Consequently, we generate enormous volumes of ultra-fine waste. Current process plants are also water intensive and these waste streams are too fine to self-drain. As a result, we store waste in wet tailings dams and struggle to recycle the water efficiently. This brings another set of challenges – poor levels of water recycling and wet tailings dams that are a safety hazard across the Industry”.
Dr Adair’s conclusion, and where he believes CRC ORE can have an impact with its research and solutions, is that effective pre-concentration in the mine is required to dramatically reduce the volume of treated material that has no value. “We then need to apply the principles of gangue rejection into the design and operation of new energy and water efficient process equipment and circuits. This will require the realisation of co-creation partnerships between selected miners and suppliers to implement these solutions quickly. Nothing less than a complete step change in energy reduction and close to full recycling of water will suffice”. Ironically, he also states that this will actually increase metal production at sites, with cheaper capital and operating expenditures proclaiming that “sustainability really isn’t a cost!”
Success with Sumitomo
Sumitomo is a major producer globally of zinc, lead and silver from their Minera San Cristóbal (MSC) operation in Bolivia. “It’s a fascinating place,” explains Dr Adair. “It operates with a head grade of around 1.7% Zn where traditionally zinc/lead/silver operations would be looking at an equivalent of >7% Zn or more. In spite of this, the operation is one of the world’s most profitable thanks to remarkable approaches in optimising process performance, combined with world class water and energy conservation.”
Located in the south-western Bolivian province of Nor Lípez, and operating since 2007, the mine produces around 1,500 metric tons of zinc-silver and lead-silver concentrates each day. To achieve this result, MSC needs to move a daily average of 150,000 tons of rock, 52,000 tons of which goes to the process plant for treatment. “To become more productive and lower costs, this operation deploys highly sophisticated mill sensors and integrated control systems which defy conventional thinking in the comminution process. Acoustic sensors linked to infra-red imaging are used to control both the SAG and Ball Mill circuits.” reveals Dr Adair.
“As a consequence, over the past five years the site has reduced absolute power consumption within their SAG (Semi-Autogenous Grinding) mill circuit by 26%, while increasing throughput of material through the comminution circuit by over 35%! In the process, they’ve also decreased consumables (liners and grinding media consumption) by 40%. Best in class effective run time in mineral processing circuits globally is around 95%. At MSC it is 97%. In short, they have achieved substantial reductions in energy with increased metal production using conventional off the shelf technology. Why can this not be repeated elsewhere in the Industry?”
Furthermore, the site is located in an arid region of Bolivia, where access to water is at a premium. Dr Adair highlights that Sumitomo has coupled its energy efforts with a substantial reduction in water consumption from external sources – from 30% five years ago, down to just 19% today. “They're now pushing towards a 90% plus level in water recycling” he says, “all of it done by integrating existing technology, albeit in a novel and sophisticated way. Surely there is a message here for what can be achieved for the sector – the outcome of which is a more sustainable operation that actually makes more money!”
The Australian-born ingenuity of CRC ORE has been put to the test by Sumitomo during a successful full-scale production trial of Grade Engineering techniques at MSC. “Sumitomo asked us a fundamental question,” notes Adair. “Is there any way to reduce the amount of barren material that you send into a process plant in the first place?”
CRC ORE’s Grade Engineering solutions deploys a range of waste rejection technologies that integrate with a suite of separation technologies relevant to ore specific characteristics. This leads to a deeper understanding of the orebody, supporting the ability to exploit inherent ore deposit heterogeneity and variability. Describing the application of this approach at MSC as a ‘co-creation partnership’, Dr Adair underlines the need to work intimately with mining companies and their suppliers to form a genuine alliance: “Ultimately, you need supply companies of scale and mining companies with vision. In this case CRC ORE worked with the MSC site and another of our participants, Metso, to engage in a full-scale production trial of Grade Engineering.”
The outcome of this trial was the ability to reject 75% of barren components in material that was originally designated as mineralised waste (not even ore feed). A 450 tons per hour Metso Loko-Track mobile screening plant was deployed on site to assist in the production scale testing. The trial focused on upgrading this and other waste targets from the pit to determine if a metal-rich stream could be generated that could be economically combined with Run of Mine (ROM) feed to the concentrator.
“So far, results show that by applying Grade Engineering to areas previously designated as ‘mineralised waste’, 25% of the material has a feed grade to the mill some 2.5 times higher than ROM ore,” says Dr Adair. “There is now the potential to convert this waste material into high grade ore-feed, with associated opportunity to increase metal production and reduce process power and water intensities. We’re now in the process of operationalising the process for the site going forward.”
MSC Operations Director Dave King believes the opportunity for the mine is huge. “One of the exciting things about Grade Engineering is that when people hear about it, they think that it’s ‘what we can do with the mine that we have’. But we’re also thinking outside the box by applying the techniques to very low-grade material to offset mine closure costs in advance with ‘Waste Engineering’. It gives you much more opportunity to think about other applications to Grade Engineering besides what it was originally intended for.”
Dr Adair points out that Sumitomo’s culture and approach to innovation has been the key to success. “The site adopts a modular and flexible approach to rapidly test and deploy new innovations. It's very much a plug and play philosophy, more analogous with what Japanese industry in other sectors does like Toyota, for example. Every piece of equipment that they (MSC) have in their operation is bristling with sensors. They measure what they do and because of the modular scenario, they can quickly test new opportunities without impacting production. A technology can be quickly implemented or rejected if it's not working. It’s a ‘lean pivoting’ approach.”
Rising to the collaboration challenge
Dr Adair points out that historically there’s been something of a standoff between mining companies and their suppliers. “The landscape is changing,” he says. “It’s a lot more collaborative and we’re seeing more joint strategic thinking that will benefit the industry as a whole. It needs to be a win-win situation with the mining company/supplier relationship. Suppliers need to be able to sell their services and products out of co-creation partnerships. Equally, however, the mining companies are entitled to some form of competitive advantage as co-creators. Traditionally, it takes around 15 years in the sector to implement an innovation from ideation to industrial deployment. Co-creation can cut this to less than five years.”
CRC ORE deploys a variety of levers for different approaches to gangue rejection. “We’re doing a lot of work with fusing sensor technology,” confirms Dr Adair. “This goes way beyond the promotion of point solutions by individual companies, so common in the industry today. Our experience has shown we need more integrated solutions. There is no silver bullet with any one approach in gangue rejection; it’s important to integrate the best of the best.”
CRC ORE is working towards this goal on a multinational basis in a series of initiatives with mining majors in Australia, Chile, Brazil, South Africa and other parts of South America. “We’re working across different commodities and a multitude of diverse ores and waste types. It is interesting that many of the principles of pre-concentration and taking advantage of heterogeneity are common to all. Our goal at CRC ORE is therefore to make a significant contribution towards a genuinely more sustainable industry going forward.