Tag Archives: ore sorting

Futureproofing the world’s copper supply through technology use

Realising the vision of a world of clean energy brings the issue of metal supply into sharp focus, with major and sustained increases required to meet growing demands, Thermo Fisher Scientific’s Ellen Thomson* writes.

With copper, for example, there are predictions of a shortfall of 15 Mt per annum by 2034 based on the current output. Therefore, boosting the efficiency of mining operations has never been more important, and smarter technology is undoubtedly the way forward to achieve this. Real-time sampling and measurement right across the mineral processing value chain can arm miners with analytical data, enabling them to build a robust understanding of the performance of each plant and drive continuous improvement at every step of the process. This article takes a closer look at how several of these steps could be optimised, including ore grade measurement, sorting on the mill feed conveyor, particle size analysis in the grinding circuit, the addition of reagents in the flotation circuit and elemental analysis and impurity detection in the concentrate leaving the plant.

Copper miners face the challenge of satisfying the rising demand for metal, while hitting the industry’s 2050 net zero carbon target. This is likely to require significant changes in operations through processing low-grade ore more efficiently, fully exploiting existing deposits, and bringing new mines into production. Unfortunately, higher-grade ore – with a 2-3% metal concentration – has largely been depleted, and miners now often work with concentrations of just 0.5%, meaning greater quantities of ore must be processed to extract sufficient amounts of copper. Therefore, it is essential to seek fresh opportunities to improve processes across the entire mining value chain, so that the increasing demand for copper ore will be met well into the future.

Does your ore make the grade?

Enhancing mining efficiency begins as soon as raw material is extracted from the ground, and extends through the crushing process and the mill feed conveyor. It is important to accurately measure the grade of the plant feed as this will impact both the performance of the concentrator and the production costs of the final product. However, this can be challenging, as some deposits are highly heterogeneous and unpredictable. Bulk ore sensing and sorting are, therefore, crucial steps in improving the raw feed material consistency and concentrator efficiency, since they reduce the dilution of incoming feeds and redirect low or marginal grade material away from the concentrator at the first opportunity. These stages rely on highly accurate and precise analytical technologies to rapidly differentiate material grade and minimise the loss of valuable material, moving only economically viable ore further along in the process. A high spec analyser is vital to this part of the chain and enables small and lower-grade satellite deposits to be accessed more successfully, as well as increasing profits for established plants.

Cracking down on the grinding circuit

Grinding is an essential first step in mineral liberation, but there is often no clear understanding of what the target particle size should be for a given head grade. Producing finer particles liberates more metal, but also increases media and energy costs. More than 50% of the energy consumed at a mine goes into crushing and grinding, so over grinding has definite economic and environmental implications. It is crucial, therefore, for each mine to find a balance between particle size and circuit throughput that limits consumption of grinding media and energy, while still maximising metal yields.

Grinding just enough is critical – too fine means lower throughput and/or higher energy consumption; too coarse and recovery suffers

Once a target has been established, real-time analysis of particle size and head grade elemental composition – for example, by prompt gamma neutron activation analysis (PGNAA) using a cross-belt system such as the Thermo Scientific™ CB Omni™ Agile Online Elemental Analyzer – can have a significant impact on the efficiency of the grinding circuit. In addition, by standardising particle size and controlling composition through the plant feed and grinding stages, the stability in feed forward control is increased going into the next stage – the flotation circuit.

The CB Omni™ Agile Online Elemental Analyzer (Thermo Scientific) rapidly and accurately differentiates material that is at or below the cut-off grade for ore sorting, the company says

Fine-tuning flotation

Flotation is a complicated physicochemical process where reagents – such as frothers, collectors and pH modifiers – are introduced to promote separation. The flotation feed can vary in particle size and chemistry depending on how the grinding circuit is optimised, and may contain excess fines. Miners might choose to compensate by adding more reagents, which can sometimes be beneficial but can also incur greater financial and environmental costs. Therefore, it is important to tailor the dosages of the flotation reagents in response to the incoming ore grade and particle size.

Concentrating on monitoring impurities

Certain impurities compromise the value of a concentrate, but they are often overlooked. Detecting impurities in the concentrate ahead of shipping reduces the chance of rejection at the receiving site – and the subsequent financial losses – and has the potential to improve ore quality, strengthen a company’s reputation and reduce the risk of penalty charges. In fact, representative sampling throughout ore extraction to concentrate the production process should be considered, but this can be extremely challenging owing to concentrated slurries, high tonnages, long distances between sample and analysis, and the expense and complexity of tackling head constraints.

Multi-stream analysers – like the Thermo Scientific MSA 3300 Slurry XRF Analyzer – are commonly employed in the mining industry, and can seem like an excellent, cost-effective solution. However, multiple streams can reduce efficiencies and lengthen the time to results – leading to less responsive control – and so their low upfront cost should be carefully balanced with their long-term implications. Choosing high quality analytical equipment that requires minimal manual input and has a proven record of reliability could help overcome these challenges and offer a better long-term solution. For example, a dedicated online sampling and elemental analysis station, such as the AnStat-330, provides a versatile and compact solution for addressing issues related to the process control of critical streams, time to results, the distance from sampler to analyser and the requirement for a metallurgical accounting quality sample.

 

 

The MSA 3300 Slurry XRF Analyzer (Thermo Scientific) measures up to 12 streams, with full stream separation retained throughout, Thermo Fisher says
The Anstat-330 Slurry Online Sampling and Elemental Analysis Station (Thermo Scientific) comes with options for additional process functionality, including distribution and pebble screening

Future-ready mining technology

It is vital to detect and understand why mining processes may be operating sub-optimally to know how to improve them. Relevant, reliable digital information is the foundation of an efficient operation and investing in more effective and continuous analysis is a key strategy for increasing return on investment. Digital twins, for example, integrate and collect data from sensors into a cloud platform to construct a complete and fully representative digital version of the concentrator. This allows miners to model different scenarios – such as changing process parameters – without interrupting the real-world activities of the mine. They aid in decision making and help to prevent unnecessary expenditure, as well as identifying any operational bottlenecks. Mining companies could potentially achieve 20 times – with some estimates up to 40 times – return on their initial investment through implementing digital twins, and more easily establish advanced, automated process control, increasing efficiency and depopulating mines.

Digital innovations are undoubtedly going to transform the mining industry and will help to reduce resource consumption and meet future sustainability goals. Without reliable, timely feedback, process control will always be on a ‘trial and error’ basis, which is no longer sufficient if miners are to fulfil the increasing copper demand ahead of us. Thermo Fisher Scientific supports the mining industry in adopting such technologies to enable dependable, timely and, often, real-time measurements that provide the data that miners need to track metal values, all the way from exiting the mine through to concentrate shipping.

*Ellen Thomson is PGNAA & Minerals Senior Applications Specialist at Thermo Fisher Scientific

NextOre, First Quantum fully commission ‘world’s largest bulk ore sorting system’

A 2,800 t/h MRA ore sorting installation at First Quantum Minerals’ Kansanshi copper mine in Zambia is now fully commissioned and using diversion hardware, Chris Beal, CEO of NextOre, told RFC Ambrian and Stonegate Capital Partners’ Copper Pathway to 2030 webinar on Tuesday.

Presenting alongside speakers from RFC Ambrian, Oroco Resource Corp and First Quantum Minerals, Beal revealed that the diversion process on what he said was the highest capacity bulk ore sorting operation in the world had now commenced, some 16-17 months after the magnetic resonance (MR) based system was installed and testing commenced.

“After a one year sensing-only trial, Kansanshi has now gone forward and commissioned and tested diverting hardware in May that has allowed them to fully transform into an inline bulk sorting system,” he said.

“With the validation of that having just gone by, this now represents the highest capacity sorting plant in the world.”

NextOre was originally formed in 2017 as a joint venture between CSIRO, RFC Ambrian and Worley, with its MR technology representing a leap forward in mineral sensing that, it said, provides accurate, whole-of-sample grade measurements.

Demonstrated at mining rates of 4,300 t/h, per conveyor belt, the technology comes with no material preparation requirement and provides grade estimates in seconds, NextOre claims. This helps deliver run of mine grade readings in seconds, providing “complete transparency” for tracking downstream processing and allowing operations to selectively reject waste material.

The installation at Kansanshi is positioned on the sulphide circuit’s 2,800 t/h primary crushed conveyor belt, with the system taking precise measurements every four seconds for tonnages in the region of 2.5 t to a precision of +/- 0.028%.

“Magnetic resonance technology, in particular, is very well suited to high throughput grade measurement – it is measuring all of the material that is going through,” Beal explained. “And these sensors like to be filled with more material.

“We hope to go larger from here. And we, in fact, have projects ongoing to do that.”

This wasn’t the only reveal Beal provided during the webinar, with the other announcement slightly smaller in scale, yet no less significant.

Seeking to address the lower end of the bulk ore sorting market, the company has come up with a mobile bulk sorting plant that is powered by MR sensors.

This solution, coming with a capacity of up to 400 t/h, has now found its way to Aeris Resources’ Murrawombie mine in New South Wales, Australia, where it is being used for a trial.

At Murrawombie, the setup sees an excavator feed a mobile crusher, with the crushed material then passed to the mobile ore sorting installation (the conveyor, the sensor, the diverter and supporting equipment). The system, according to Beal, provides bulk ore sorting results in a cost- and time-efficient manner.

It has been designed to suit small mines and those seeking to monetise historical dumps, or to provide a rapid test method for bulk sorting to support a potentially much larger bulk sorting plant, Beal explained.

The fully-diesel setup is destined for copper operations globally and potentially some iron ore mines, he added.

Hatch identifies opportunities to cut Australian tailings generation by as much as 30%

A new report from multi-disciplinary engineering, operational and development project, Hatch, estimates Australia’s mining waste can be reduced by 30% using already available technologies.

One of the biggest challenges currently facing the mining industry is managing the volume of tailings generated as minerals mining ramps up to meet the demands of the transition to renewable energy.

Undertaking an in-depth analysis to identify the technologies required to reduce or eliminate tailings of six key commodities (copper, gold, nickel, iron ore, coal and bauxite), Hatch investigated how tailings production would be impacted by applying the key technologies ‘themes’: advanced geometallurgy, ore sorting, advanced sensing and particle sorting, in-situ extraction, and preferential fracturing.

The company’s analysis revealed that technologies available today could reduce tailings by 20-30%, also identifying that, in the next 10-20 years, the integration of these technologies in future projects or expansions could provide an opportunity to reduce tailings by more than 50%.

Managing Director of Australia and Asia at Hatch, Jan Kwak (pictured), says the challenge of reducing tailings is a complex effort that is best solved utilising the innovative capacity of the entire mining supply chain.

“A balanced spread of researchers, METS (mining equipment, technology and services) companies, and operators in the mining industry are actively commercialising technologies,” he said. “Half (50%) of stakeholders identified are METS companies, whose core business is the supply of equipment and services of these technologies, indicating commercialisation is underway. This group was also present across the technologies that our analysis has shown to have higher TRLs (Technology Readiness Levels).”

The TRL ranking system measures the maturity of technologies, whereby Hatch graded technologies from zero (idea stage) to nine (commercial application).

For in-situ mining and preferential fracturing technology themes, there is a larger representation of research organisations and partnerships. This suggests collaboration is required to advance technological development, according to Hatch.

“It is vital that these stakeholders are highly engaged in the tailings reduction challenge in order to achieve the greatest cut through and introduce real change and advancement in the reduction of tailings, which will be needed to support the increase in mining activity while meeting emissions reduction targets,” added Kwak.

Teck’s Carmen de Andacollo goes live with MineSense shovel-based ore sorting system

Following a successful trial of a MineSense’s ShovelSense ore sorting unit at Teck Resources’ Carmen de Andacollo mine in Chile, the operation is now using the system to divert trucks in real-time, MineSense says.

The implementation of an additional ShovelSense system at CDA is now also underway, the Vancouver-based company says.

CDA is Teck Resource’s second mining operation using ShovelSense, following commercialisation in 2019 at Highland Valley Copper (HVC) in British Columbia, Canada.

“The ShovelSense results are spectacular!” Victor Araya, Teck Superintendent Geology, said, referring to the results of the trial recently completed.

All new technology introduced into the mine is rigorously tested at different stages of evaluation at scale to ensure the system works reliably in the field, according to MineSense. ShovelSense exceeded one-digit accuracy (single-digit relative error) measuring copper ore and met and exceeded expectations for all criteria in the trial: system availability; accuracy to blast hole data; and precision in the field, the company reported.

Teck CDA also recently celebrated the diversion of seven ore-from-waste trucks, which are the first of many that ShovelSense data will automatically divert to maximise ore recovery and minimise the needless transportation and processing of waste, MineSense said.

“We have now incorporated ShovelSense to decide the destination of the materials, not at the block scale, but truck to truck, due to the reading of grades on each shelf of the loading equipment… the end result is increased ore to mill tonnage and also a significant improvement in feed grade,” Araya concluded.

Claudio Toro, EVP Business Development at MineSense, added: “We are proud that Teck has chosen to partner with MineSense again, demonstrating confidence that ShovelSense is a proven and valued technology. Global mining operations are continually seeking new ways to get more value out of their mines and extend the life of mine and we are pleased to again be chosen by Teck.

“ShovelSense is a proven solution that unlocks a mine’s full potential.”

Hear more about Teck CDA’s installation on April 25 when MineSense and International Mining will be holding a joint webinar titled, ‘Ore sorting at the extraction face’ at 10 am EST/4pm CEST. Click here for more information

Tungsten West breaks ground at Hemerdon for TOMRA XRT ore sorters

Tungsten West says it has broken ground at its Hemerdon tungsten-tin mine in Devon, England, with the first sod turned for the installation of the TOMRA X-ray Transmission (XRT) sensor-based ore sorters.

This event, the company says, marks another major step in the company’s upgrade and refurbishment plans for the project’s processing plant.

Hemerdon is, Tungsten West says, the third largest tungsten resource globally, as well as being a previously producing mine that was operational from 2015-2018. Tungsten West purchased the Hemerdon Mine in 2019, and has since completed a bankable feasibility study that demonstrated an extensive reserve of approximately 63.3 Mt at 0.18% W and 0.03% Sn, as well as 37.4 Mt of saleable aggregate material. The company estimates that the life of mine is currently 18.5 years with the opportunity to extend this through future investment.

As announced earlier this month, the company took receipt of important long-lead equipment items, including the seven XRT ore sorters, which will make up part of the upgraded equipment the company plans to install into the front end of the processing plant. The XRT ore sorter will substantially improve and streamline operations once production restarts, minimising plant downtime, increasing recovery as well as a host of ESG benefits, it said.

After significant test work, Tungsten West engaged TOMRA to supply the seven units that are required to treat the run of mine throughput. This consists of six duty units and one standby unit. Orders and deposits for these units were placed in 2021 and the units have now been delivered to the UK and await final transfer to Hemerdon where they will be installed in the front end of the processing plant.

Additionally, the company is pleased to announce the appointment of James McFarlane as Managing Director of Tungsten West. McFarlane previously held the position of Technical & Operations Director of the company.

Max Denning, Tungsten West CEO, said: “We are extremely excited to have broken ground at Hemerdon this week, marking an important milestone in the project’s restart. Ensuring the UK and the western hemisphere have got access to two key critical minerals has never been more profound. We are also delighted to announce James as our new Managing Director; his extensive experience will prove invaluable in the company’s development as we move closer to first production at Hemerdon.”

TOMRA continues to build ore sorting Insight across mining space

Some 18 months after launching TOMRA Insight to mining customers, the cloud-based data platform is making inroads across the North American mining sector, Harold Cline and Jordan Rutledge told IM on the side lines of the MINEXCHANGE 2022 SME Annual Conference & Expo in Salt Lake City recently.

TOMRA rolled out the subscription-based service to mining back in late 2020, with one of the early adopters being the Black chrome mine in South Africa, one of two mining projects that form the basis of the Sail Group’s plans for long-term sustainable chrome production.

TOMRA Insight, the company says, enables sorting machine users to improve operational efficiencies through a service that turns these machines into connected devices for the generation of valuable process data.

Cline and Rutledge, both TOMRA Sorting Area Sales Managers for North America, said numerous customers were now taking advantage of TOMRA Insight across the region, with many more interested in leveraging the continuous data streams coming off a web-based portal stored securely in the cloud.

TOMRA’s Harold Cline & Jordan Rutledge

“This is seeing mine managers able to tap into how operations are performing today, while tracking that against performance over the last day, week, month, quarter, etc,” Cline told IM. “With the help of our support network, these operations are able to achieve more consistent performance.”

With more customers signing up to TOMRA Insight and more data being generated, the pair were confident future iterations of the platform would be able to offer machine-learning algorithms that helped, for example, predict failures or highlight potential areas for operational improvements.

At the show, the pair were also highlighting the ongoing demand for TOMRA’s Final Recovery sorter, the COM XRT 300/FR, which, since launch, has been successfully deployed at the Letšeng diamond mine in Lesotho, owned by Gem Diamonds. The solution has gone on to be rolled out at other operations.

The introduction of the COM XRT 300/FR, TOMRA became the first company in the industry able to supply a full diamond recovery solution using XRT technology from 2-100 mm, with the unit delivering concentration factors of up to one million with limited stages and guaranteeing more than 99% diamond recovery, according to the company.

Outside of diamonds and sorter analytics, Cline was keen to talk up demand from the gold sector for the company’s sorters.

One of the key differentiators of its offering to the yellow metal space is the ability to scan the material with a multi-channel laser sensor. In an ore sorting setup that involves both XRT and LASER sensor-based machines, the TOMRA solution can remove particles containing sulphide minerals using XRT and subsequently leverage laser sensors to remove particles containing quartz and calcite.

TOMRA says its segregated option can potentially improve recoveries in quartz-associated gold applications thanks to a laser chute-based machine that analyses rocks from both sides. Other belt-based laser machines can only analyse a maximum of 40% of the rock’s surface, according to TOMRA.

“In the gold scenario, we are using XRT to sense and sort with sulphide minerals as a proxy,” Cline said. “At the same time, our laser scanner allows further separation capabilities through identification of minerals such as quartz and calcite.”

Vista Gold, which is developing the Mt Todd project in Australia, anticipates that this combined solution could eliminate approximately 10% of the run-of-mine feed to the grinding circuit, allowing the company to decrease the grind size and thereby increase recovery of the contained gold.

The COM XRT 300/FR offers a full diamond recovery solution

Cline added: “In North America, we have three projects in the gold space we’re working on at the moment that appreciate our unit’s ability to analyse the whole of the particle through our chute mechanism, as opposed to conveyor-based systems that can only analyse one angle of the particle.”

While TOMRA offers multiple sensors on its units through its modular platform, Rutledge said the company continues to have discussions on combining its solutions with other bulk sorting suppliers to further improve the process, naming prompt gamma neutron activation analysis (PGNAA) technology as one specific area of interest.

“We very often refer clients on to other companies when our solution may not match their brief,” she said. “At the same time, we have done some flowsheet work to include our solution with others currently on the market and believe it is only a matter of time before a combination of the two comes into a flowsheet.”

Tungsten West makes EPCM progress at Hemerdon as TOMRA XRT ore sorters hit the road

Tungsten West has named Fairport Engineering Limited as its engineering, procurement and construction management (EPCM) contractor at the Hemerdon tungsten-tin project, in the UK, as well as confirmed it was soon expecting to receive seven X-ray Transmission (XRT) sensor-based ore sorters from TOMRA.

Since successfully listing on the AIM Market of the London Stock Exchange, Tungsten West has been advancing the development of Hemerdon, which is one of the most advanced mining projects in England and is expected to be a key future global supplier of tungsten and tin.

Hemerdon is, Tungsten West says, the third largest tungsten resource globally, as well as being a previously producing mine that was operational from 2015-2018. Tungsten West purchased the Hemerdon Mine in 2019, and has since completed a bankable feasibility study that demonstrated an extensive reserve of approximately 63.3 Mt at 0.18% W and 0.03% Sn, as well as 37.4 Mt of saleable aggregate material. The company estimates that the life of mine is currently 18.5 years with the opportunity to extend this through future investment.

On top of the ore sorters, Tungsten West said the rest of the long-lead items had been ordered and were scheduled for delivery within the company’s timetable. It plans to recommence mining this year.

The upgrade and refurbishment of the existing processing plant at Hemerdon is centred around the optimisation of the existing concentrator circuit as well as the introduction of a new crushing and screening circuit that will then feed into a new XRT ore sorting stage. These upgrades will streamline processing, minimise plant downtime and improve recovery rates, according to the company.

After significant test work, Tungsten West engaged TOMRA to supply the seven units that are required to treat the run of mine throughput. This consists of six duty and one standby units. Orders and deposits for these units were placed in 2021 and the units have now been delivered to the UK and await final transfer to Hemerdon where they will be installed in the front end of the processing plant.

On top of this, six new screens and 11 vibrating pan feeders have been ordered from Vibramech of South Africa at fixed prices. These will replace the existing large screens, which caused the low frequency issues, and were a key contributor to plant downtime under Wolf Minerals – the previous owner of Hemerdon. Delivery is expected in the June quarter of 2022.

Max Denning, Tungsten West CEO, said: “We are extremely pleased with progress at site, particularly the onboarding of Fairport Engineering to undertake the detailed design and construction of the project. We are looking forward to working with Fairport as we move towards restarting full production at Hemerdon, with a substantially improved processing route, through the introduction of XRT ore sorting and upgraded processing equipment. The company has assembled a strong projects and operations team, and we remain confident in our progress.”

Australian Government backs EQ Resources Mt Carbine ore sorting plan

EQ Resources Ltd says it has successfully secured A$600,000 ($422,386) in co-investment from the Australian Federal Government’s Advanced Manufacturing Growth Centre (AMGC) via the A$30 million Commercialisation Fund. Combined investment from EQ Resources, its partners and AMGC, totalling A$1.97 million, will assist in commercialising industrial-scale operations for advanced minerals processing flowsheet developed for the Mt Carbine Expansion Project, in Queensland, EQ said.

Technologies to be incorporated include the advanced X-ray Transmission ore sorting technology from TOMRA Sorting Pty Ltd, as well as hyperspectral imaging sensors developed by Plotlogic Pty Ltd. The implementation will further be supported by Cronimet Australia Pty Ltd and The University of Queensland – Sustainable Minerals Institute, it said.

The formal co-funding agreement between AMGC and the company has been finalised and signed.

AMGC is an industry-led, not-for-profit organisation established through the Australian Government’s Industry Growth Centres Initiative. AMGC’s vision is to transform Australian manufacturing to become an internationally competitive, dynamic, and thriving industry with advanced capabilities and skills at its core.

AMGC’s Managing Director, Dr Jens Goennemann, said: “EQ Resources’ project brings together industry and research leaders to commercialise a world-leading technology which will convert what was once a mining waste product into new revenue streams. The project proves that Australia’s manufacturing industry is stepping forward to develop globally relevant solutions which will improve operations and add value in the process.”

EQ Resources, as a result of the acquisition of Mt Carbine Quarries in June 2019, now has 100% ownership of the two mining leases and surrounding exploration projects at the project. In a joint venture with Cronimet, the tungsten processing plant has been refurbished, commissioned and expanded to 300,000 t/y capacity. The installation of the pilot sensor-based sorting technology has seen a 20-plus times upgrade of feedstock grade, the company says.

The company is in the process of completing the required environmental amendments to allow the operation to process 300,000 t/y and eventually 1 Mt/y. Once the bulk test work is completed, a feasibility study will be completed for the design of the 1 Mt/y operation.

Hudbay’s Constancia continuous improvement quest leads to MineSense XRF trial

Hudbay Minerals has one of the lowest cost per tonne copper sulphide operations in Peru on its hands at Constancia, but it is intent on continuously improving the mine’s margins and environmental performance through a commitment to continuous improvement. This has recently led it to exploring the potential of sensor-based ore sorting.

Hudbay’s operations at Constancia include the Constancia and Pampacancha pits, an 86,000 t/d ore processing plant, a waste rock facility, a tailings management facility and other ancillary facilities that support the operations.

The company increased reserves at the mine, located in the Cusco department, by 33 Mt at a grade of 0.48% Cu and 0.115 g/t Au last year – an increase of approximately 11% in contained copper and 12% in contained gold over the prior year’s reserves.

With the incorporation of Pampacancha and Constancia North, annual production at Constancia is expected to average approximately 102,000 t of copper and 58,000 oz of gold from 2021 to 2028, an increase of 40% and 367%, respectively, from 2020 levels, which were partially impacted by an eight-week temporary mine interruption related to a government-declared state of emergency.

Constancia now has a 16-year mine life (to 2037) ahead of it, but the company thinks there is a lot more value it can leverage from this long-life asset and it has been looking at incorporating the latest technology to prove this.

In recent years it has, for instance, worked with Metso Outotec to improve rougher flotation performance at Constancia using Center Launders in four e300 TankCells and installed a private LTE network to digitise and modernise its open-pit operations.

Peter Amelunxen, Vice President of Technical Services at Hudbay, said the Constancia ore sorting project – which has seen Hudbay partner with MineSense on a plan to trial the Vancouver-based cleantech company’s ShovelSense X-ray Fluorescence (XRF)-based sorting technology – was one of many initiatives underway to further improve the operating efficiency at Constancia.

“The ore sorting program is separate from the recovery uplift program at Constancia,” Amelunxen said, referring to a “potentially high-return, low capital opportunity” that could boost milled copper recovery by 2-3%.

He added: “The ore sorting program is expected to yield positive results at the mining phase of the operation and is expected to increase the mill head grade and reduce metal loss to the waste rock storage facility.”

Back in April 2021 during a virtual site visit, Hudbay revealed it was trialling bulk sorting at Constancia as one of its “optimisation opportunities”, with Amelunxen updating IM in mid-January on progress.

Hudbay has previously evaluated particle sorting at its Snow Lake operations in Manitoba – with the benefits outlined in a desktop study “muted” given “bottlenecks and constraints”, Amelunxen said – but, at Constancia, it considered XRF sorting from the onset for copper-grade only pre-concentration, due to its perception that this application came with the lowest potential risk and highest probability of success.

The company has a three-phase evaluation process running to prove this, with phase one involving a “bulk sorting amenability study”, phase two moving up to laboratory-scale testing and phase three seeing trials in the field.

The “bulk sorting amenability study” looked at downhole grade heterogeneity to estimate curves of sortability versus unit volume, Amelunxen detailed. Laboratory testing of drill core samples to evaluate the sensor effectiveness was then carried out before an economic analysis and long-range-plan modelling was conducted.

With the concept and application of bulk sorting having cleared all these stage gates, Hudbay, in November, started pilot testing of XRF sensors on a loader. This involved fitting a ShovelSense unit onto the 19 cu.m bucket of a Cat 994H wheel loader, with around 20 small stockpiles of “known grades” loaded onto the bucket and dispatched into a feeder and sampling system (pictured below, credit: Engels Trejo, Manager Technical Services, Hudbay Peru). With this process completed, the company is now awaiting the results.

At a similar time, the company moved onto demonstration trials of a “production” ShovelSense sensor unit on the 27 cu.m bucket of a Hitachi ECX5600-6 shovel operating in one of the pits. It has collected the raw spectral data coming off this unit since the end of November, with plans to keep receiving and analysing sensor data through to next month.

“We should have the finalised XRF calibration in February, at which time we’ll process the raw data collected during the three-month trial period and compare it with the short-term mine plan (ie grades of ore shipped),” Amelunxen said. “So, by the end of February or early March, we’ll be able to validate or finetune the economic model.”

Should the results look favourable, Amelunxen is confident that leasing additional sensors and installing them on the other two Hitachi ECX5600-6 shovels will not take long.

Credit: Engels Trejo, Manager Technical Services, Hudbay Peru

“Plans may change somewhat as the program unfolds,” he said. “For example, we may have success sorting ore, but feel additional calibration is required for waste sorting at Pampacancha, in which case we may install production sensors on Constancia ores while doing another trial program at Pampacancha.

“It all depends on the precision of the XRF calibration.”

Higher head grades and potentially higher copper recoveries may be the headline benefits of using ore sorting technology, but Hudbay is equally focused on obtaining several key environmental benefits, including reduced consumption of energy and water.

On the latter, Amelunxen said: “This is expected due to the processing of less ‘waste’ by removing uneconomic material earlier in the process and reducing the hauling and processing costs of the uneconomic material.”

Looking even further forward – past a potential commercial implementation of XRF-based ore sorting at Constancia – the company plans to evaluate the application of other sensors, too.

“For our future development copper project in Arizona, we plan to look at other sensors as well,” Amelunxen said, referencing the company’s Rosemont asset.

This ore sorting project is not the only project the processing team at Constancia are examining, as Amelunxen already hinted at.

As part of the recovery uplift project, it is installing equipment that will allow the operation to increase the overall mass recovery of the roughers, which is currently constrained by the downstream pumps and cleaning circuit.

“This will allow us to achieve an expected 2-3% increase in copper recoveries without impacting concentrate grade,” Amelunxen said.

It has various initiatives underway under the “Moly plant improvement projects” banner, too. This includes flowsheet optimisation, pH control in the cleaners and pH reduction in the bulk cleaners.

“This project has been in the works since late 2019, and the new mechanical agitator installation in the cleaning cells was completed during the August 2021 schedule mill maintenance shutdown and the new nitrogen plant was commissioned in the second half of the year,” Amelunxen explained. “The next steps are pH control in the cleaners (with CO2), water balance optimisation and potentially installing a Jameson flotation cell as a pre-rougher (the cell is already on site and not in use, it will be repurposed pending results of the pH trials).”

A flotation reagent optimisation study is also on the cards, aimed at reducing zinc and lead contamination in the copper concentrate.

“A depressant addition system is on the way to site and should be installed in February, with plant trials commencing in March,” Amelunxen said, explaining that this followed laboratory test work completed in 2021.

TOMRA Mining’s ore sorting solution helps Renison tin mine do ‘more with less’

TOMRA Mining and its X-ray Transmission (XRT) technology has, the company says, provided an effective solution for the extreme conditions at the Bluestone Mines Tasmania JV (BMTJV) Renison tin mine in Tasmania, Australia, with sensor-based ore sorting solution unlocking significant value and delivering environmental benefits.

The Renison mine is 50% owned by Metals X through the BMTJV, and is the only major tin mine in production in Australia with a mining rate of close to 1 Mt/y, according to TOMRA. While slated capacity is 1 Mt/y, the concentrator is restricted to 750,000 t/y.

The mine’s extreme humidity and highly acidic processing water (pH around 4.5) create unique challenges for the sorting process, the equipment and waste management, according to TOMRA.

A complex flowsheet

The underground mine operates a primary crushing system before the material is transported to the surface through a shaft. Once there, it enters the pre-concentration plant, where it undergoes a three-stage crushing, screening and cleaning process. The particles are split into two fractions – 10-25 mm and 25-60 mm – which are fed into two TOMRA XRT sorters. The output consists of two streams: the product, which is transferred to the wet plant, and the waste, which is fed into a TOMRA EM sorter to separate acid-forming sulphides from this waste stream.

In the wet plant, the product goes through primary grinding followed by bulk sulphide flotation. The tailings are processed downstream to concentrate the cassiterite tin mineral through gravity concentration; gravity tails are further treated via desliming and tin flotation. The combined concentrates are fed to a leaching circuit to remove carbonate minerals. After a final wash stage, the concentrate is de-watered and dispatched.

BMTJV approached TOMRA to address two key requirements at the plant. The first was the need to upgrade the tin feed to the plant, as Ben Wraith, Principal Project Metallurgist at BMTJV (pictured below), explained: “The Renison tin operation wanted to achieve economies of scale, putting more tonnes through the front end of the plant without upgrading the back end downstream – we wanted to do more with less.”

The second requirement was to address the environmental issue of removing acid-forming sulphides from the waste.

Following site visits and extensive discussions with BMTJV’s teams, TOMRA proposed a solution that addressed the tin feed quality with two COM Tertiary XRT 1200 sorters and the waste issue with a COM Tertiary EM 1200 sorter. A team from BMTJV visited the TOMRA Test Center in Sydney, Australia, where they observed what the XRT sorter operating at capacity is capable of.

Gavin Rech, Technical Manager at TOMRA, said: “Our XRT stands out for the high spatial and density resolution and its ability to do contrast sorting, identifying fine high-density tin inclusions in the ore with an accuracy that has no equal on the market. On top of that, it can separate it from the acid-forming sulphides, so that we have the ability of pulling the tin into the first product and sending the rest to the EM sorter.”

Gavin Rech, Technical Manager at TOMRA

The two COM Tertiary XRT 1200 sorters went into operation in 2018. Initially, BMTJV’s strategy focused on low reject grades, devoting less focus to achieving the mass reject rate and overall process plant throughput. However, the specific conditions at the Renison mine affected the results achieved. The large variance in run of mine (ROM) particle size distribution resulted in insufficient stability in the feed to the circuit. In addition, the extremely wet conditions in west Tasmania and consequent high ambient moisture content, combined with the high moisture of the ore delivered from underground, further affected the sorting process.

In 2019, a new investigation was conducted into the ore sorting performance and led to a change of direction, where the operation shifted away from targeting low reject grades, towards sorting as aggressively as possible, according to Wraith, moving from a “tin recovery-based” operating strategy to a “mass reduction” one.

“We are getting 20-25% mass reduction, so 75-80% of the materials are going into the wet plant, and we are still achieving 97-98% tin recovery overall across the crushing circuit,” he said. “Pre-concentration didn’t materially impact overall recovery because the tin in the material that is rejected as waste is extremely fine grained and a proportion is associated with sulphides, so it wouldn’t have been fully recovered in the downstream wet plant and would have been lost to tailings.”

This approach, he said, is best for Bluestone’s application as it provides the ability to process 15-20% more tin units without having to upgrade the downstream concentrator.

Wraith added: “Operating the sorting circuit has slightly increased our overall processing cost, but this is more than offset by the large increase in ROM throughput by 15-20% and, thus, tin production, so the unit cost per tonne of tin produced is reduced by almost 10%. We’ve broken multiple production records in the last year in tin units, and this gives us confidence in what we can achieve because the machine performs over and over again if you treat it right and if you prepare your feed correctly.”

TOMRA XRT success leads to upgrade decision

In view of the results achieved with the two TOMRA XRT sorters, BMTJV decided to upgrade the ore sorting circuit with two new, recently launched XRT models with stainless steel internal parts and advanced features such as the TOMRA ACT user interface and the TOMRA Insight cloud-based platform, according to TOMRA.

“The decision to buy new machines was easy,” Wraith said. “The stainless steel will assist prolonging the TOMRA sorter’s life by protecting the unit from our high-moisture and corrosive environment. The more ergonomic design will help our maintenance teams, which is particularly important for machinery operating in these harsh conditions.”

Wraith said the use of TOMRA Insight, the ore sorting company’s subscription-based service that relays and analyses machine data, will “enhance everybody’s understanding and experience of the machines”.

He added: “It will be more of an analytical platform for our metallurgy and maintenance staff, providing ample opportunity to gain valuable information that can be analysed and optimised over time. The one feature I am personally interested in is the particle size monitoring through the machines, which will enhance our overall circuit performance because we have an integrated circuit with the crushing and screening plant. Feed preparation is key to maintain a consistent performance – knowing how well you’re preparing your feed in a live fashion can only end up with a better result.”

TOMRA will also be able to log into the machine and check the daily reports generated by TOMRA Insight, so its technical teams will be prepared ahead of site visits for maintenance or optimisation.

Wraith concluded: “TOMRA has been working with the site maintenance team to tailor solutions to our operating environment, which has been invaluable. TOMRA supported me through site visits, which included equipment inspections, site-based training of our personnel, and an openness to continually improving the technology and finetune it to our site-specific requirements. They assisted the site with troubleshooting, optimisation, discussing the nuts and bolts of the issues as they arose, and finding a solution that works.”