Tag Archives: sensor-based sorting

TOMRA Mining talks sulphide ore sorting in copper, zinc, lead space

When processing sulphide ores to extract copper, zinc or lead, the focus is on ensuring that the mill is always operating at full capacity. The challenge is to optimise the process by eliminating waste in the early stages and maintain a high recovery rate, TOMRA Mining says.

This means that less barren or low-content rock will be processed, consequently increasing the metal content in the input of the mill. The result: significant cost savings and reduced environmental impact per produced tonne of metal.

In the case of copper, the mineralogy and lithology of the ore will affect how effective sorting can be at removing waste. When sorting copper sulphides with a non-disseminated texture, the focus is on waste removal to maximise recovery. However, three quarters of global copper production come from porphyry deposits, where very small grains of the metal are disseminated, making detection particularly challenging. Zinc and lead sulphides present similar sorting challenges to non-disseminated copper, although the metal content in the mineral is typically higher, so the focus will be on waste removal while maintaining the recovery levels.

The technology to sort copper, zinc and lead sulphides effectively to optimise the process is available from TOMRA Mining, it says. Its X-ray Transmission (XRT) sensor-based sorting technology can effectively detect sulphides in mineralised run of mine materials as they carry elements with higher atomic densities than non-mineralised waste rocks. After crushing, the ore in a size range from +8 mm to 80 mm is fed into the sorters and the barren and low content rocks are eliminated, resulting in a higher head grade of the mill feed. In addition, the eliminated waste can be replaced in the mill with more upgraded sulphides, increasing the efficiency of the mineral process.

However, in order to maintain the capacity of the mill, it is necessary to increase the amount fed to the crusher. This will have an impact on the mine and extraction planning. Due to the lower processing costs of sensor-based sorting, it is also possible to bring this in the calculation of the resource evaluation and the final pit design, according to TOMRA Mining.

TOMRA’s XRT sorters scan the individual rocks fed into the machine on a conveyor belt with overhead X-ray sources. At the same time, detectors located inside the belt collect data from the ore. The position of sensors, close to the rocks, combined with the strong X-ray power sources result in extra high-resolution images. This enables TOMRA’s XRT sorters to effectively process even most of the challenging porphyry copper disseminated deposits. Waste rocks are ejected by high-precision, fast pneumatic module, which adds to the sorter’s efficiency.

In copper sulphides with disseminated texture, a TOMRA XRT sorter can achieve an upgrade ratio of copper content in the mill feed ranging from 20% to 100%, while separating 20%-45% of mass as the waste material. With porphyry copper, the cut-off grade is typically 0.5%, but in view of the surging demand, it is now often as low as 0.2-0.3%. With TOMRA’s XRT technology, it is possible to achieve high recovery rates even at the lower grade, as shown by the tests conducted on run-of-mine samples from at OZ Minerals’ Antas Norte mine, in Brazil, the company says. The sorter demonstrated its ability to achieve recovery rates of at least 90% or reduce the waste grade down to 0.3% copper.

Heitor Mesquita Carmelo, Plant Manager at OZ Minerals Brazil, explains: “A bulk test was conducted to evaluate TOMRA’s XRT technology, and subsequently, the company decided to test it continuously in a pilot installation at the Antas Norte site. The results were consistent in both tests, demonstrating that the technology is effective for industrial application. TOMRA’s technology holds significant potential for OZ Minerals Brazil’s strategic plan, with the possibility of making deposits with lower ore grades viable, reducing operational costs, enhancing transportation safety for pre-concentrated ore, as well as decreasing the CO2 emission resulting from this activity.”

Heitor Mesquita Carmelo, Plant Manager at OZ Minerals Brazil

In lead and zinc sulphides, tests conducted by TOMRA have shown that it is possible to achieve an upgrade ratio of two to three times lead or zinc in the output of the sorter. Here the mineralisation plays an important role and can dramatically affect the upgrade ratio, TOMRA Mining says.

TOMRA’s XRT sorter delivers multiple benefits for copper, zinc and lead mining operations, beginning with its uniquely high capacity, which can be as high as 150-200 t/h per sorting width meter – a differentiator of TOMRA’s which also meets the requirements for medium- and large-size operations, it says. The sorter’s operational efficiency can be further improved with TOMRA Insight, a cloud-based subscription service that turns the sorter into a connected device that generates process data. It enables mining operations to monitor and measure performance in real time and optimise the process as well as tracking faults to improve maintenance and keep the plant always operating at its best.

Another important benefit of the sorter is the capacity to lower operating costs through its efficiency and energy saving features such as its ejection module that uses compressed air to eject the particles – up to 80% less compared to other ejection systems – dramatically reducing energy consumption compared to conventional sorting machines.

Optimising the process also reduces its impact on the environment. In addition, TOMRA’s XRT technology is a dry process, so that the overall use of water and chemicals is also reduced.

TOMRA’s latest XRT advances open up processing options for miners

When it comes to particle sorting, size is everything. Whether used as a primary sorting method in smaller operations where product purity is paramount to profits, or in a scavenger setup downstream to capture value once lost to tailings, particle sorters are becoming more and more commonplace across the mining world.

They have featured in flowsheets in the industrial minerals space for decades, but they are now finding their way into metal operations all over the world as miners look to boost recoveries, reduce their energy consumption and, in many instances, rationalise their water use.

This makes TOMRA Mining’s latest advances in sensor-based ore sorting all the more significant.

The company is now breaking ground with a new ejection module for its COM Tertiary XRT (X-ray Transmission) sensor-based sorter specifically developed for sorting small particle sizes.

The COM Tertiary XRT Fines sorter, featuring the new TS100C module and the recently introduced image processing unit, is capable of sorting particle sizes down to 4 mm in high-capacity applications with much higher energy efficiency, delivering a high-quality product at low operating costs, according to the company.

The COM Tertiary XRT Fines sorter featuring the new TS100C ejection module has been installed at the TOMRA Test Center in Wedel, Germany

The high resolution TS100C ejection module features a new type of ejector that is four times faster than previous iterations, according to the company. Together with the new image processing unit, it delivers higher precision in sorting small particle sizes at high throughputs.

The mechanical design of the sorter has also been improved by the introduction of a new splitter plate and more precise calibration equipment to ensure the greater precision in the alignment between detection and ejection systems required for fine particles, according to TOMRA.

This has been captured in field tests that started back in May 2022, showing an up to 30 t/h boost in capacity, an increase in product recovery and a reduction in energy consumption.

Ines Hartwig, Director Product Management at TOMRA Mining, told IM on the side lines of the recent SME MINEXCHANGE 2023 Annual Conference & Expo in Denver, that the company had been able to visualise such small size particles previously, but the mechanical ejection function had not been able to keep up.

“This new ejection module is a significant leap forward for TOMRA, and we believe the whole particle sorting setup within the industry,” she said.

And, while the industrial minerals sector was the first one pushing for these developments, Hartwig said she expected the metal miners to also benefit from this.

“We have visited operations all over the world that have stockpiled fine material as they simply couldn’t process it with the technology on the market,” she said. “We’re now opening up many new opportunities for these companies.”

To gain field experience on the new ejection module, TOMRA partnered with a customer who has been running a COM Tertiary XRT to produce high-grade magnesite for more than two years. The sorter removes up to 50% low-grade and waste material from the raw magnesite feed, with particle sizes ranging from 10 to 35 mm at about 20 t/h.

Ines Hartwig, Director Product Management at TOMRA Mining

“After conducting the test work with the TS100C ejection module at the TOMRA Test Center, we were confident that it would be very beneficial for this customer,” Hartwig says. “We showed them the test results and outlined the benefits we expected the module to deliver. As soon as they saw the possible reduction in compressed air use and the consequent cost savings, they were very interested in doing the field trial!”

The customer, the magnesite operation in Turkey, completed several trials, documenting the energy savings and sorting efficiencies. The results showed a 70% reduction in air consumption with an increase in product recovery with a lower mass pull to waste by producing the same product quality, and a capacity increase ranging from 20 t/h to 30 t/h with comparable results, according to TOMRA.

The COM Tertiary XRT Fines sorter featuring the new TS100C ejection module has been installed at the TOMRA Test Center in Wedel, Germany, and is ready to run tests for customers on material samples from their mines, TOMRA says.

Hartwig said she expected existing COM Tertiary XRT customers to upgrade to the new module with the company’s retrofit solution, but there were also many new customers expected to acquire brand-new units.

“There is a significant ‘new’ market out there that we expect to take advantage of this technology,” she said. “The economic and environmental value case at many of these operations can be vastly improved by using the COM Tertiary XRT Fines sorter.”

TOMRA Mining looks at the ore sorting fine print with latest innovation

TOMRA Mining says it is breaking new ground with a new ejection module for its COM Tertiary X-ray Transmission (XRT) sensor-based sorter specifically developed for sorting small particle sizes.

The COM Tertiary XRT Fines sorter, featuring the new TS100C module and the recently introduced image processing unit, is capable of sorting particle sizes down to 4 mm in high-capacity applications with much higher energy efficiency, delivering a high-quality product at low operating costs, according to the company. Field tests have shown that it can deliver a 70% reduction in energy use on a production scale.

The new high resolution TS100C ejection module features a new type of ejector that is four times faster than previous iterations. Together with the new image processing unit, it delivers higher precision in sorting small particle sizes at high throughputs. The mechanical design of the sorter has also been improved by the introduction of a new splitter plate and more precise calibration equipment to ensure the greater precision in the alignment between detection and ejection systems required for fine particles, according to TOMRA.

The fast and highly precise ejection module uses significantly less compressed air to eject the particles, therefore, reducing the energy consumption. Extensive test work was conducted at the TOMRA Test Center, both with artificial material mixtures and real-world sample material. The tests showed a reduction in air consumption compared with industry standards, as well as an improvement in product purity of around 15%, the company reports.

“With the consequent cut in operating costs, sorting small particle sizes down to 4 mm with the COM Tertiary XRT Fines sorter is not only viable, but adds value to the process,” it said.

Ines Hartwig, Director Product Management at TOMRA Mining, said: “We are receiving a rapidly growing number of requests from customers to sort smaller particles. One of the biggest drivers of cost in sensor-based sorting is the energy used for the compressed air for the ejectors. The new TS100C ejection module successfully addresses this issue and provides an effective solution to this increasing demand. It is a groundbreaking invention to create more higher-value product and reduce product loss.”

Ines Hartwig, Director Product Management, TOMRA Mining

To gain field experience on the new ejection module, TOMRA partnered with a customer who has been running a COM Tertiary XRT to produce high-grade magnesite for more than two years. The sorter removes up to 50% low-grade and waste material from the raw magnesite feed, with particle sizes ranging from 10 to 35 mm at about 20 t/h.

“After conducting the test work with the TS100C ejection module at the TOMRA Test Center, we were confident that it would be very beneficial for this customer,” Hartwig says. “We showed them the test results and outlined the benefits we expected the module to deliver. As soon as they saw the possible reduction in compressed air use and the consequent cost savings, they were very interested in doing the field trial!”

The customer completed several trials, documenting the energy savings and sorting efficiencies. The results showed a 70% reduction in air consumption with an increase in product recovery with a lower mass pull to waste by producing the same product quality, and a capacity increase ranging from 20 t/h to 30 t/h with comparable results, according to TOMRA.

The COM Tertiary XRT Fines sorter featuring the new TS100C ejection module has been installed at the TOMRA Test Center in Wedel, Germany, and is ready to run tests for customers on material samples from their mines, TOMRA says.

TOMRA’s XRT solution creates value from waste at Mina Esperanza de Caravelí in Peru

The integration of TOMRA’s ore sorting technology at the Mina Esperanza de Caravelí mine in Peru has helped the polymetallic miner produce more metal as well as clean up its legacy tailing operations.

The close collaboration between two companies emphasises a shared philosophy, that of making the most of natural resources and embracing a circular economy.

Mina Esperanza de Caravelí, owned by MTP and operated by Minera Croacia, is a polymetallic vein deposit with a mining rate of 150 t/d. It is located in the district of Atico, in the Nazca-Ocoña geological gold belt in the southern part of Peru, and contains narrow veins with a rosary formation, of which over 30 have been discovered so far. The mineralisation is located in vein fill fractures of hydrothermal origin and are mesothermal in appearance.

In 2019, Minera Croacia contacted TOMRA to explore a solution to extract value from low-grade material previously deemed uneconomical, and to address the environmental issue of metals left in the dumps.

Marco Fernandez Concha, Senior Geologist to Minera Croacia, said: “Mining operations need to find ways to optimise the use of natural resources while reducing waste and their impact on the environment as much as possible. With TOMRA’s ore sorting technologies, this is possible.”

A sensor-based ore sorter represents a significant investment for a mine the size of Minera Croacia, according to Emilio Uribe, Senior Metallurgical Advisor at Minera Croacia.

“When we purchase important equipment, we need to analyse the solution in great detail because we can’t afford to make mistakes,” he said. “We need it to work and deliver the results we want from the start. TOMRA has adapted to our needs as a small business with limited resources. They have been an important advisor, giving us all the support we needed with highly qualified and knowledgeable staff. They have really committed to the project and found the solution that meets our operational needs and is financially viable for us.”

The teams from TOMRA and Minera Croacia worked closely to precisely analyse the requirements and identify the best solution. TOMRA’s Test Center in Wedel, Germany, conducted three series of tests on samples from the mine to narrow down the requirements. A technical team from Minera Croacia attended the final session, which gave them a better understanding of what TOMRA’s XRT technology could do for their operation.

Christian Korsten, who at the time was the Test Center’s Manager, said: “This project stands out for presenting different types of ores from different locations. Usually we test one or two different ores for a customer, but, with Minera Croacia, we had different metallogenic veins. They were all a little bit different in mineralogy, sensor response and in the customer’s objectives for each.”

Strong communication between the two companies’ teams was crucial to the successful outcome – especially since COVID-19 travel restrictions limited the opportunities for face-to-face meetings.

Mathilde Robben, TOMRA Key Account Manager, said the company ensured Minera Croacia received the support and advice they needed throughout the process.

“We did it all through online meetings,” she said. “The management team and staff at Minera Croacia were always to the point and friendly, and together we completed this fast-track project.”

Korsten agreed: “Minera Croacia had very clear objectives. All our questions were answered in a perfect, fast and professional manner, and the same applies to the discussion of the test results. This project was one of my favourites in almost 10 years in the Test Center.”

Following the detailed analysis of the test results and Minera Croacia’s requirements, Robben proposed the use of a TOMRA COM Tertiary XRT sorter as the solution: a machine suited to the particle size range of the dump material (-25 mm/+ 10 mm and -40 mm/+ 25 mm) and an investment that fitted Minera Croacia’s budget.

The test results made a clear business case for the sorter, showing that out of 1,300 t of run of mine material containing gold and copper, 21% are fines (-10 mm) and screened out. This results into a concentration of gold and copper in the fines and, therefore, this material does not need to be sorted. Of the rest of the material, 34% is enriched, going from a grade of 2.7 g/t gold-equivalent to 5.12 g/t gold-equivalent – almost double.

This leaves 45% of the material discarded as waste with very low metal content, 0.41 g/t gold-equivalent, which addresses the environmental issue, as it contains virtually no contaminants. This also shows that maximum value has been extracted from the material, as there is virtually no gold left, TOMRA said.

Uribe said: “The test has shown that TOMRA’s sorter can create value from material that would have gone to the waste dump, from 33% of the run of mine that is too low-grade for processing to be financially viable.”

The TOMRA COM Tertiary XRT sorter is now installed and has been operating since December 2021 re-processing the mine’s 800,000 t of historic dumps. It is delivering on all counts for Minera Croacia: now able to increase the grade of the dump material that was not considered economic, it has reduced freight costs of the operation as it is now transporting less low-grade material to its processing plant, and it has successfully addressed the environmental impact of its waste materials.

Uribe concluded: “All the calculations we made when we evaluated this investment are being fulfilled. The sorter’s performance is perfectly consistent with the test results, and we expect it to pay for itself as planned within two years – including the other components and infrastructure of the circuit.”

The company’s management is so impressed with the results achieved that it is considering investing in further sorters for low grade run of mine ore with the aim of extracting value from mineral that is currently considered marginal, according to TOMRA.

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.”