Tag Archives: TOMRA

TOMRA sensor-based ore sorters shine at quartz operations

Bulk handling, Comminution of minerals, Industrial minerals, Mineral processing, Mining equipment, Mining services, Sustainable mining, Water management, , , , , , , , ,

TOMRA says its patented multi-channel laser sorting technology is helping unlock the “full potential” of quartz deposits.

Quartz is one of the most common minerals found in all forms of rock, but it does not exist in high purity in nature, according to TOMRA. The challenge for mining operations serving the metallurgical and engineered stone industries is to reliably deliver quartz of consistently high chemical purity.

The scattering effect of the multiple laser beams from TOMRA’s ore sorting technology can be used to separate quartz-bearing rock from waste rock, with the sensors recognising the glowing crystals that are the tell-tale sign of quartz or quartz veins.

TOMRA says large and pure crystals can be clearly discriminated from other rocks or minerals with a smaller crystal structure, regardless of the colour or chemical composition.

“TOMRA’s laser sorter also stands out for being a gravity system rather than the conventional conveyor belt, so that both sides of the material are scanned and multiple characteristics such as surface structure, size, shape, brightness and colour distribution are processed simultaneously,” the company said. “Laboratory tests and field experience have shown that the recovery of valuable rocks can be increased by 20% while improving the quality of the product.”

Jens-Michael Bergmann, Industrial Mineral Segment Manager at TOMRA Sorting Mining, said the advantages for mine operations are multiple, “from a longer life of the mine to lower operating costs and a reduction of waste, with consequent lower haulage costs”.

He added: “It also enables them to guarantee consistent high-quality of product to their customers.”

TOMRA’s laser sorting technology also has environmental benefits due to the reduced waste and low water use, as only a small quantity of water is required for wet washing the rocks at the beginning of the process to avoid dust in the processing plant.

Laser sorting also eliminates the need for hand picking, which is required with colour sorting in order to achieve the high purity levels demanded by the metallurgy and engineered stone industries, according to TOMRA. This has a positive impact on the mining operation’s health and safety initiatives, as personnel are not exposed to silicon dust in the sorting process.

Spanish company Erimsa, part of Elkem ASA, one of the world’s leading suppliers of silicon-based advanced materials, has over 30 years’ experience in quartz extraction using an environmentally friendly method, according to TOMRA.

It specialises in the production of aggregates for the construction industry and metallurgical quartz, which means a consistently high chemical purity of the quartz is paramount. It originally achieved this level of quality through manual sorting, but, in 2000, the company introduced colour sorting technology.

TOMRA said: “However, in order to achieve the high level of purity they required, the sorters were calibrated in a way that resulted in high rejection rates of material containing quartz. This meant that hand picking was still required in order to improve the recovery and ensure the stability in the quality of the quartz that is key for Erimsa.”

Carlos Forján, Quality Manager at Erimsa, turned to TOMRA for its laser technology, which he thought would enable the company to sort good quality quartz regardless of the colour: “The main problem we have is in the complexity of sorting automatically when the quartz and the rejectable minerals have the same colour. I thought that laser technology would be the way to address this.”

In 2016, following tests conducted at TOMRA’s Centre in Wedel, Germany, a PRO Secondary LASER Dual sorting machine was installed at its processing plant in Salamanca.

At this operation, the quartz is extracted and washed to avoid dust in the plant, then it is screened by size. Materials over 70 mm are hand-picked by four operators; materials under 20 mm are shipped to aggregates and quartz sand customers; materials between 20 and 70 mm are fed to the TOMRA multi-channel laser machine, which sorts out the waste material. A final quality check is conducted by two operators to remove the rare pieces with quartz content that may have been ejected in the waste by the sorter, as it is calibrated to maximise recovery.

Forján said: “The TOMRA machine has enabled us to reduce costs while increasing our yield; our production has easily increased by 20% compared to when we used colour sorters combined with hand picking. Material that, in the past, was lost to the waste pile is now generating profit for us.

High quality quartz after TOMRA’s laser ore sorting

“The stability of the quality is an important goal, and we have achieved this with the laser sorter. It has been such a game-changer in our operation; we are planning the purchase of a second laser machine to replace an existing colour sorter.”

TOMRA’s laser sorters can also be combined with other sensors depending on the requirements.

This is the case for Mikroman Mining Company, which uses a combination of TOMRA laser and TOMRA colour sorters to differentiate products according to four qualities: white and light grey quartz with low iron oxide content for engineered stones; grey and yellow quartz for the glass industry; coloured quartz for ferrosilicon used in the metallurgical sector; and coloured gravel, also for ferrosilicon, which currently goes into the waste pile.

These precise distinctions, resulting in higher product quality, were not possible before the acquisition of the TOMRA machines, and today the company operates 13 colour sorters and three laser sorters in its various plants, according to TOMRA.

TOMRA’s XRT ore sorting aids recoveries, costs at South Africa chrome mine

Comminution of minerals, Mineral processing, Mining equipment, Steel and iron ore, Sustainable mining, Water management, , , , , , ,

One of TOMRA’s X-ray Transmission (XRT) sensor-based ore sorters is helping improve recoveries and lower costs at a South Africa chrome operation.

As South Africa chrome mining operations have increased production in the face of rising demand from stainless steel buyers, the cost of using traditional methods for separating low-grade chromite material, such as dense media separation (DMS), cyclones and spirals, has increased. XRT ore sorting, an established technology in physical separation that has proved extremely effective in mining operations for a variety of minerals, including chrome, is another pre-concentration route they are looking into.

“Its benefits are significant: less complexity in the process, considerably lower costs, higher productivity and profitability – and the added advantage of a lower environmental impact,” TOMRA, a supplier of XRT solutions, said.

The X-ray sensor accurately establishes the density of each particle in the feed, and high-speed pneumatic ejectors separate ore with high chromite content from barren or low-grade ore at throughputs between 60-200 t/h. “The resulting output is a high-grade product that is ready to sell, with no need for additional comminution,” the company said. “It is a dry process that requires no water or reagents, and is frugal in its energy consumption, resulting in a fraction of the capital expenditure and running costs of traditional methods, as well as a smaller footprint.”

Engineering and project management company P2E Consulting has first-hand experience of the advantages of TOMRA’s XRT technology in sorting chrome ore at Eastern Chrome mines, in South Africa. It was looking for a solution to improve the efficiency of the sorting plant and turned to TOMRA.

“We have installed TOMRA sorters on diamond and copper plants in the past and we believe their technology is ahead of their competitors,” Craig Meadway, Business Development Executive of P2E Consulting, said.

P2E Consulting commissioned a TOMRA COM XRT 2.0 sorter to replace an existing drum DMS plant.

“The mine used the DMS plant to produce saleable small lumpy product from the mine’s LG6 Chromite run of mine and dumps at a minimum grade of 38%, but it was very inefficient,” Meadway explains. “The TOMRA XRT sorter has resolved this issue. It is used to upgrade under value material with a head grade of 20-28%, to produce a saleable product at a minimum grade of 38% Cr2O3. It does this efficiently and at a low cost of production.”

The TOMRA COM XRT 2.0 sorter has exceeded Meadway’s expectations, with grades being achieved in excess of 40% Cr2O3 and mass recoveries of 25-30% from scalped waste resulting in chrome-in-tails as low as 12%.

“No other technology has given us such a high recovery rate. Not only that, with TOMRA’s XRT there was no water usage at all, and we didn’t need to spend on expensive reagents, so that we are producing small lumpy product for approximately 50% of the cost compared to a DMS plant,” he said.

The environmental benefits of TOMRA’s XRT solution were also an important factor in P2E Consulting’s choice of technology. “We are looking to introduce greener technologies into the mining industry. The fact that no water or chemicals are used is a major advantage,” Meadway said. “Also, South Africa has major power limitations, and the lower energy consumption when compared to DMS is a huge driving force.”

The ease of operation of TOMRA’s XRT sorters proved to be a further advantage: “It is very easy to use: once the sorter and feed system control philosophy is set up correctly, the plant runs with very little input from the operators,” Meadway said.

TOMRA’s collaborative approach and all-round support was also an important factor in P2E Consulting’s decision to turn to them for this project, according to Meadway.

“We knew from our experience in previous projects that the support from TOMRA is very good, and with the installation of this machine in a relatively new application, it was excellent,” he said. “The local team has bent over backwards to help us make this happen.”

TOMRA strengthens southern Africa ore sorting ties with new regional HQ

Comminution of minerals, Environmental, Industrial minerals, Mineral processing, Mining services, Sustainable mining, , , , , ,

TOMRA says it has opened new regional headquarters in Johannesburg, South Africa, to strengthen its commitment to customers in southern Africa.

The initiative is designed to enhance customer care through even better technical support, service and training, and to ensure prompt availability of spare parts, it said. The move will also improve operational efficiencies by bringing together under one roof all three TOMRA business divisions: Mining, Recycling, and Food.

TOMRA’s new facilities are housed in a two-story, 1,800 sq.m building which accommodates offices, a warehouse, spare parts area, two training rooms, and three meeting rooms connected to TOMRA’s global network of more than 4,000 employees. There is also the space here to demonstrate TOMRA’s sensor-based sorting technologies.

The building’s location on the edge of the Longmeadow Business Estate, Edenvale, to the northeast of Johannesburg, is conveniently close to major road networks and the city’s airport.

The most senior executive at the new headquarters is Albert du Preez, Senior Vice-President and Head of TOMRA Mining. Du Preez said: “This investment affirms TOMRA’s wholehearted and long-term commitment to southern Africa. This is a growing market, and one we take very seriously. The 26-strong team operating out of our new headquarters will support customers in South Africa and all other countries in Sub-Saharan Africa.”

With the mineral industry such a valuable source of export earnings, it is hugely important to national economies in Sub-Saharan Africa, TOMRA said. The African continent can produce up to 500 t/y of gold and accounts for a large share of the world’s diamonds, according to the company.

In April last year, a 1,758 ct diamond, one of the largest in recorded history, was recovered in Botswana through TOMRA X-Ray Transmission (XRT) sorting technology. South Africa is also a crucial global supplier of chrome ore and ferrochrome, exporting 8.5 Mt of ferrochrome annually, mostly to China, and TOMRA’s sorting solutions are ideal for the production of these minerals, it said.

Speaking from TOMRA’s new South African headquarters, Helga van Lochem, Sales Manager of TOMRA Sorting Mining, said: “Opening new premises confirms TOMRA’s belief in southern Africa as a big player in the global market, and our commitment to supporting mining businesses here in the long term. Investment in sorting solutions pays back handsomely and now our new training facility in Johannesburg can empower customers to get the most from our profit-enhancing technologies.”

TOMRA says it manufactures sensor-based sorting solutions for almost every mineral application: diamonds, industrial minerals, ferrous metal, non-ferrous metal, slag metals, and coal and other fuels.

XRT ore sorting shows promise at Vendetta Mining’s Pegmont project

Base metals, Comminution of minerals, Environmental, Mineral processing, Mineral project development, Mining equipment, Mining services, , , , , , , ,

Following positive X-ray Transmission (XRT) ore sorting test work on the Pegmont asset, in Queensland, Australia, Vendetta Mining is looking to apply this technology in its next mining study at the lead-zinc project.

The test work, conducted at TOMRA’s testing facility in Sydney, Australia, concluded that the XRT sorters could distinguish between high-density/high-grade feed and lower-density waste material at Pegmont, the company said.

Vendetta said: “At Pegmont, the potential advantages of XRT material sorters is that they could allow plant feed material to be screened prior to grinding and flotation, removing lower density external dilution (waste) and lower-grade internal dilution (material below cutoff).”

Potential capital cost savings occur through the reduced mill throughput while potential operating costs savings occur through reduced water and reagent usage, less pumped tails and lower energy requirements, it said.

The test work envisages that sorted waste product would be ejected and stacked for dry disposal (dry stack tailings).

Vendetta said: “Flotation recovery often improves with increasing head grade. Such a relationship exists in the metallurgical test work performed at Pegmont to date. The higher head grades obtained from the ore sorted product are anticipated to result in enhanced flotation recovery.”

The testing involved material from two drill hole intersections from Zone 5 and one from Zone 2 at Pegmont. The sulphide intersections were selected in order to test different lead to zinc ratios (Zone 5 vs Zone 2) and internal grade distributions, it said. All samples included diluting quartzite material from the hangingwall and footwall.

The conclusions of the XRT ore sorting preliminary test work on the three drill intervals are it can successfully remove the external dilution from the samples; and successfully remove internal diluting material from within the higher-grade intervals.

The total mass tested amounted to 139.2 kg, with the mass pull (weight % of feed recovered) ranging from 44.3% to 70.6% (a weighted average of 62.3%).

The lead grade improved from 18% to 88%, a weighted average of 42%; zinc grade improved from 21% to 72%, a weighted average of 38%; lead recoveries ranged from 83.2% to 90.2%, a weighted average of 88.5%; and zinc recoveries ranged from 76.4% to 92.2%, a weighted average of 85.9%.

Vendetta said that while these results were highly encouraging, they are preliminary. “In order to apply material sorting results in an updated preliminary economic assessment (PEA) study, pilot scale test work is necessary,” the company said.

TOMRA recommends 600 kg of material is required for each ore type at Pegmont. Vendetta plans to pursue this test work and expects these samples will be obtained from the next drilling program. Samples will be obtained from Zone 1 transition, Zone 2-3 sulphide and Zone 5 sulphide.

Michael Williams, President and CEO, said: “At Pegmont, the XRT sorter can clearly differentiate between high density/high grade feed from lower density waste material at Pegmont. We are excited by the prospects of advancing to pilot scale test work and applying this commercially available technology to the next mining study.”

The existing Pegmont PEA contemplated a production rate of 1.1 Mt/y, which corresponds to two TOMRA COM XTR 1200 – generation one ore sorters, Vendetta noted.

Vital moves towards REO production with mining, road construction and ore sorting contracts

Comminution of minerals, Energy minerals, Mineral processing, Mineral project development, Mining equipment, Mining services, , , , , , , ,

Vital Metals says it has agreed multiple development and supply contracts that will assist it in rapidly becoming North America’s next rare earth mining company.

The ASX listed company’s Cheetah subsidiary has signed preferred mining contractor and ice-road construction contracts for its Nechalacho rare earth project, in the Northwest Territories of Canada, with Det’on Cho Nahanni Construction and Aurora Telecom Services, respectively. These contracts allow for the mobilisation of plant and equipment to site over the winter to enable site establishment works to be completed in preparation for operations to commence in 2020.

In addition to this, it has also issued a purchase order to acquire COM Tertiary X-ray Transmission (XRT) 1220/B ore sorting equipment from TOMRA Sorting Inc for C$1.4 million ($1.07 million).

All three of these moves follow close on the heels of the delivery of a 95 Mt JORC-compliant resource at Nechalacho and positive concentration and hydrometallurgy test work.

Vital Metals Managing Director, Geoff Atkins, said: “The signing of these agreements marks an important milestone in the development of the Nechalacho rare earth project as they provide the foundations for enabling Vital Metals to become a producer of rare earths in 2020 through the processing of material from the North T zone. These contracts and agreements also provide prospective customers with a far greater level of confidence in potential delivery dates to progress offtake negotiations.

“Further, by confirming the use of sensor-based ore sorting technology to produce a concentrate, it will remove the requirement for traditional reagents, process water and tailing facilities used in typical ore beneficiation.”

The decision to acquire the TOMRA ore sorter follows excellent results achieved from the recently completed ore sorting test work that produced a high grade (+35%) concentrate, Vital Metals said.

The COM Tertiary XRT 1220/B ore sorter is the same machine used in test work to produce the high-grade product, it said. The purchase order includes supply, installation, commissioning and spare parts, with delivery of the sorter to Yellowknife scheduled for June 2020.

“The ore sorting test work highlighted that the Nechalacho REO project is one of the few and the first REO project to successfully use ore sorting to produce a high grade +35% REO concentrate without the use of reagents and water,” the company said. “This will substantially reduce the cost and the lead time to bring the Necalacho REO project into production.”

Novo heralds ore sorting developments as it lines up Steinert and TOMRA trials

Environmental, IoT, Mineral exploration, Mineral processing, Mineral project development, Mining services, Precious metals, Sustainable mining, , , , , , ,

Novo Resources Corp says it is planning mechanical sorting test work on multi-tonne samples of gold-bearing conglomerate from its Beatons Creek project (pictured) and gold-bearing gravels from its Egina project, both in Australia, with Steinert Global and TOMRA.

Mechanical sorting of small particles of gold is seen as a potentially important breakthrough for Novo and its various nuggety gold projects throughout its large land holdings across the Pilbara, the company said.

An approximate 5 t sample of Beatons Creek gold-bearing conglomerate and an a similar sized sample of Egina gold-bearing gravel have been shipped to Perth for sorting trials at Steinert Global’s test facility in December. Conglomerate from Beatons Creek is being crushed and screened, and gravel from Egina is being screened in preparation for test work.

Once mechanical sorting tests have been completed at Steinert Global, bulk test material will be shipped to TOMRA’s test facility in Sydney for testing during the March quarter of 2020, Novo said.

Novo, earlier this month, said recent tests of Steinert mechanical sorting equipment had demonstrated recovery of fine gold nuggets as small as 0.4 mm, which was a significant step toward a potentially cost-effective “dry and chemical free” means of gold recovery.

The test work is designed to assess the veracity of recent advances in scanning and sorting capabilities of both companies, while determining – on Egina material, at least – the gold recovery capabilities of this technology as a means of primary separation; the applicability of mechanical sorting as a tool to support field exploration activities; and which model of mechanical sorter is preferred for deployment for field trials.

“Owing to recent rapid advancements in mechanical sorting technology, Novo has conceptualised a potentially viable alternative ‘dry’ processing pathway for Beatons Creek,” it said.

While testing is required to better assess sorter manufacturer claims that fine gold particles can be detected and sorted, according to Novo, the company said it sees considerable merit in this ‘dry’ processing model for the following reasons:

  • Potential to significantly reduce capital and operating costs compared to conventional ‘wet’ processing schemes;
  • Potential to reduce construction timeframe compared to conventional ‘wet’ processing;
  • ‘Dry’ processing schemes might be amenable to modular design suited to cost-effective mobilisation and relocation;
  • Negates or minimises use of water and chemicals; and
  • ‘Dry’ processing could help unlock Novo’s other assets in the East Pilbara region.

Successful mechanical sorter trials of Beatons Creek material are anticipated to lead to a larger metallurgical test work program to fully assess means of crushing, screening and sorting to be incorporated to a process flowsheet, the company said, adding that it foresees using proven technologies given there is a spectrum of commercially available equipment for dry crushing, grinding and screening.

Rob Humphryson, CEO and director of Novo Resources Corp, said: “The pace of development of mechanical sorting technology continues to astound us. We are fortunate that our nuggety gold deposits appear to lend themselves to ‘dry’ processing pathways involving mechanical sorters, technology that may generate favourable economic and environmental outcomes.

“Considering we can readily access outcropping gold mineralisation on all of our properties, we have a unique opportunity to quickly collect bulk samples for testing mechanical sorting technology on a meaningful scale.”

Hastings, TOMRA see potential for XRT ore sorting at Yangibana rare earths project

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TOMRA’s X-ray Transmission (XRT) ore sorting innovation has another positive industry reference to hand after Hastings Technology Metals said off-the-shelf technology had proven extremely effective at removing dilution on samples used in the testing program at its Yangibana rare earths project in Western Australia.

Testing on a 1.8 t sorted bulk sample had seen a 95.1% recovery of contained Nd2O3+Pr6O11 (neodymium and praseodymium), a 52% increase in head grade from 0.71% to 1.08% Nd2O3+Pr6O11, and a 37.1% mass rejection, Hastings said.

This shows XRT technology could be applied to separate out a barren waste stream from the ore, according to the ASX-listed company, presenting an opportunity to remove waste dilution material from the mining process before the material is fed into the processing plant – resulting in energy and reagent savings in the beneficiation circuit.

The testing involved the crushed bulk ore sample of 1.8 t being screened into two size fractions (10.5 mm) and (plus-10.5mm), with the sortable fraction (plus-10.5 mm)after being diluted with waste material at either 35% or 60% proportions screened on a TOMRA commercial sorter using XRT technology at 32 t/h feed rate.

In the base case, sorted ore samples, crushed and screened to plus-10.5 mm and diluted with 35% waste material, a total of 37.1% of the sample mass was rejected at a grade of 0.09%Nd2O3+Pr6O11, representing a loss of Nd2O3+Pr6O11 of just 4.9%, or an overall recovery of 95.1%Nd2O3+Pr6O11 in the ore. A corresponding 52% increase or upgrade in the ore head grade was achieved from 0.71% to 1.08% Nd2O3+Pr6O11.

In the sorted sample diluted with 60% waste material, the ore sorting test work program achieved an upgrade factor of 2.16 taking the feed grade from 0.43% Nd2O3+Pr6O11 to 0.93%Nd2O3+Pr6O11, while recovering 90.6% of the Nd2O3+Pr6O11, the company said.

Hasting said: “The full opportunity for including ore sorting technology into the Yangibana process flowsheet is still being assessed. Based on these test work results, technical and engineering programs will continue to investigate the benefits that can be realised across the project.”

The proposed beneficiation and hydro metallurgy processing plant at Yangibana will treat rare earths deposits, predominantly monazite, hosting high neodymium and praseodymium contents to produce a mixed rare earths carbonate that will be further refined into individual rare earth oxides at processing plants overseas, according to Hastings.

A definitive feasibility study in 2017, based on a 5.15 Mt reserve, detailed a production rate of 1 Mt/y to produce up to 15,000 t/y of mixed rare earths carbonate at Yangibana.

TOMRA XRT makes a difference at Kazakhstan coal operation

Coal technology, Mine operation news, Mineral processing, Mining services, , , , , ,

TOMRA’s X-Ray Transmission (XRT) sensor-based technology has been delivering higher yields and quality output while reducing operating costs at Gamma LLP’s coal mining operation in Kazakhstan, according to the technology company.

Gamma LLP, part of the Zaman Group, has been operating a TOMRA COM Tertiary XRT 1200 belt sorting system since 2014 at its coal mine in the Bayanaul district in Pavlodar, the main coal mining region in the Republic of Kazakhstan.

Abgujinov Bekbolat Sovetovich, Director of Gamma LLP, said: “The TOMRA XRT sorter has improved the efficiency of our operation and we are consistently achieving higher yield with a better quality of output.

“In addition, we are benefiting from lower energy and water consumption, and an overall reduction in operating costs. This equipment has made a real difference and we are planning to invest in a second unit.”

The TOMRA COM Tertiary XRT 1200 belt sorting system is based on a planar projection of X-ray attenuation of single particles in a stream to identify and separate materials according to their specific atomic density, according to TOMRA. It effectively and accurately sorts materials irrespective of size, moisture, dust or dirt on the surface, so that pre-washing or surface cleaning is not necessary.

The XRT sensor-based separation makes it possible to extract from the stream both high ash material and coal with any amount of ash content. The system analyses each particle and extracts the coal of the required quality to the concentrate.

The system was commissioned and installed by TOMRA’s partner in Russia and CIS, THRANE, which shares the company’s approach to working with its customers: “The support we have received from THRANE has also been excellent; they are always available and ready to help whenever we need it,” Sovetovich commented.

Studies conducted by THRANE at its test centre bear out Gamma LLP’s experience. The company analysed the qualitative and quantitative characteristics of de-stoning and the results, which were presented at the XVIII International Coal Preparation Congress in 2016, were impressive, TOMRA said.

When separating size fractions of -100+25 mm of K-rank coal with 17.5-16.5% initial ash content, the TOMRA XRT separator produced a concentrate of less than 10.7-11% with the output of 65 and 70%, respectively, according to TOMRA.

With size fractions of 100+10mm T-rank coal with 39-42% initial ash content, it produced a concentrate of less than 26-32.5% ash with the output of 60% and 70%, respectively.

With size classes of -70+25mm of T-rank coal with 39-42% initial ash content, the concentrate produced was 8.2% at its output of 60%. Size classes of -80+13 mm of A-rank coal with 11.1% initial ash content produced a concentrate of less than 4.3% at its output of 80%.

TOMRA seminar highlights sensor-based ore sorting benefits

Comminution of minerals, Environmental, IoT, Mineral processing, Mining events, Mining services, Sustainable mining, Water management, , , , , , , , , , ,

TOMRA recently held a seminar on sustainable mining solutions and sensor-based sorting that, it said, addressed major challenges of the mining industry, including increasing pressure to be more financially streamlined and radically more efficient, while addressing environmental and sustainability concerns.

Sensor-based sorting (SBS) is proving to be an increasingly important tool both to formulate optimal solutions for greenfield projects and to help conquer challenges for keeping brownfields operations viable, converting the mining operation’s resource into value, according to TOMRA.

During this seminar at the Colorado School of Mines, TOMRA’s specialists were joined by guest speakers to examine all aspects of a sensor-based sorting operation with a broad range of topics including sorting technology, applications, plant design, test work and economic considerations.

The 62 participants came from all across the US and Canada, and included representatives from mining companies, engineering firms and students and professors eager to learn more about the applications and technology.

Corby Anderson, Harrison Western Professor at the Colorado School of Mines, opened the seminar with an introduction of recycling, recovery and sorting. The next talk focused on sensor-based sorting technologies and their applications, as well as highlighting fully operational SBS plants in the mining industry.

TOMRA’s Mathilde Robben explained the importance of setting objectives for SBS and the financial and technical aspects to evaluate.

“The most critical factors to consider when assessing the feasibility of sorting are throughput requirements, particle size and potential water usage, as well as the mineralogy of the ore,” TOMRA said, adding that having a clear understanding of where sorting can benefit in the process is paramount when planning to use this technology.

Test work is the best way to determine if SBS will work for an application, and TOMRA’s Chris Korsten explained the company’s test work philosophy to identify the best solution that will meet the mining operation’s specific conditions and objectives.

Guest speaker Erik Stepperud of Hazen Research, the industrial R&D company specialising in the mining, chemical, energy and environmental industries, shared his expertise in assays and interpretation of test results, while Craig Murray of the Saskatchewan Research Council spoke about testing and support services for projects using sorting technology.

Downstream impacts

When designing optimal sorting plants, it is critical to understand the necessary auxiliary components for materials handling, such as screens, washing and conveying, and where to place the sorter in the flowsheet to optimise the process and get the most out of SBS, according to TOMRA.

Particle size is critical to SBS, so designing optimal crushing and screening units is vital, and TOMRA invited expert speakers to cover these topics: Jörn Rohleder of Outotec, which specialises in designing leading technologies and services for the sustainable use of natural resources, discussed crushing design and Eli Cannell of Joest, a leader in vibration technology, elaborated on screening. Greg Black of Golden Eagle Technologies, meanwhile, covered the topic of dust extraction.

SBS can have a huge positive impact on the downstream operations of a flowsheet, as more waste is rejected from the process upstream. This means waste is not carried through the rest of the process, resulting in significant savings in energy, water and chemicals. A further benefit is the reduction of fine tailings that are environmentally challenging to manage.

The seminar was very well received, according to TOMRA, and achieved its goal of providing a pragmatic foundation on SBS projects. Genevieve Gosselin, Senior Technical Metallurgist at Agnico Eagle Mines, said, “The seminar gave us keys for the implementation of ore sorting in brownfields and greenfields mining projects”. Vera Gella, Metallurgist at BBA, said: “For us, the test work preparation and flowsheet design are most relevant to what we do every day and being able to quickly assess whether or not sorting is applicable to a given project. Like Jörn pointed out, if you pick the wrong crushing/SBS circuit design up front, it can drastically change the outcome of a project. It’s critical to think carefully about how to get the most out of your sorting circuit.”

It also raised awareness of aspects that participants may not have considered in the past. For Gosselin it was “how important the geology of the deposit is, and the need to evaluate this before starting bench and pilot scale testing”. Gella, on the other hand, was struck by the sustainability aspect, which is becoming increasingly important: “One of the things that we hadn’t thought about because our scope was focused on the economic tradeoff was the environmental impacts of SBS. The environment is becoming more and more of a focus for all stakeholders and will be a key driver for mining projects going forward.”

Vista Gold sorts Mt Todd ore processing issues with TOMRA’s XRT technology

Comminution of minerals, Mineral processing, Mineral project development, Mining equipment, Mining project news, Precious metals, , , , , , , ,

Vista Gold has turned to TOMRA Sorting Mining’s ore sorting technology to reignite the Mt Todd gold project, in the Northern Territory of Australia.

Mt Todd, which was acquired in 2006, hosts one of the country’s biggest undeveloped gold resources. A recently completed prefeasibility study outlined a 50,000 t/d operation producing 413,400 oz/y of gold over the 13-year mine life at Mt Todd, with average all-in sustaining costs of $746/oz.

Mt Todd briefly operated in the 1990s, but is known for having hard ore that can prove tricky when finding an efficient processing route.

Fred Earnest (pictured below), President and CEO of Vista Gold, said: “We had a desire to find a way to only be spending money to process the rock that had gold in it. We started looking for ways that we could get rid of the non-mineralised host rock prior to the grinding circuit.”

The company looked at different technologies to address the issues at Mt Todd and contacted TOMRA to find out about its sensor-based sorting technology, Earnest said.

TOMRA invited the Vista Gold team to visit its testing facility in Germany with a sample from the project to see first-hand what could be achieved, TOMRA said.

The test was an eye opener for Fred Earnest, according to the technology company: “In every evaluation of new technology, we have ‘aha moments’. For us it was the day we were at the facility in Germany watching our rock be sorted on a production-scale machine. When we saw how fast it was happening, when we saw the product sorted and rejected, and when we were able to pick it up and look at it – we realised that this was not just a dream, this was real technology being applied at a production rate to our rock.

“All of a sudden, we realised that this was technology that would work for us at Mt Todd and that we needed to evaluate more seriously.”

Following extensive testing, Vista Gold has integrated TOMRA’s two-stage sorting solution in its planned flowsheet at Mt Todd: the system sorts 20 t/h, using X-ray Transmission (XRT) technology to remove particles containing sulphide minerals and subsequently lasers to remove particles containing quartz and calcite.

The benefits of TOMRA’s solution to the Mt Todd project are two-fold, according to the company.
On the one hand, operating costs have been reduced: “We’re getting rid of material and we’re not spending money grinding rock that has no value,” Earnest explains. On the other hand, gold recovery has improved: “We’ve been able to make design changes in the plant. Because we’re processing less material, we’re now able to do a finer size. With finer grind, our gold recovery has gone up. This has resulted in improvements of grade by 10%. Our feed grade to the mill has gone up from 0.84 g/t to now 0.91g/t.”

What’s more, the savings in operating costs have paid for the improvements to the plant, according to TOMRA.

Earnest said: “We’ve been able to achieve all of this on a capital-neutral basis. We’ve been able to incorporate the equipment for the sorting to add fine grinding equipment, all with the money that we’ve saved from the ball mills.

“And, so ore sorting has opened up a whole new window of opportunity for us with the Mt Todd project. We’re very excited about what this technology means to the mining industry and specifically to our projects in the future. And we look forward to seeing this technology grow and become even more efficient and of greater value to us.”

TOMRA says it worked closely with Vista Gold’s team to identify the best solution for the Mt Todd project – from testing rock from the mine at its facility in Germany, to analysing the situation at the project and advising on how its sensor-based sorting technology could fit in its operation to deliver the best results.

Earnest added: “We have been thoroughly impressed with the team at TOMRA. We’ve done a number of tests with them, we’ve worked with them closely. The people at the [testing] facility in Germany have been very accommodating. We’ve been able to be there on the floor, watching the test, looking at the results, asking questions. It’s helped us immensely to have this open exchange with the team at TOMRA and we look forward to a very long relationship with them.”