Tag Archives: pre-concentration

Metso Outotec on ore sorting’s potential ‘revolutionary change’

Metso Outotec stands out among the mining original equipment manufacturers for having publicly acknowledged ore sorting is on its radar.

The Outotec business had a relationship with TOMRA Sorting Solutions dating back to 2014 when the two companies signed an agreement that would see the particle sorting company supply Outotec-branded sorting solutions to the mining and metallurgical industry. Metso, meanwhile, has previously disclosed it was developing “breakthrough proprietary technology to address the demand of high throughput accurate sorting”.

Close to eight months after the two companies merged to become Metso Outotec, IM put some questions to Erwin Huber, Vice President, Crushing and Conveying Systems; David Di Sandro, Business Development Manager – Optimisation and Test Labs; and Rashmi Kasat, VP, Digital Technologies, Minerals, to find out the current state of play with ore sorting at the mineral processing major.

IM: Back in November at your Capital Markets Day, there was mention of ‘AI-powered Ore Sorting Solutions’ during a presentation. Can you expand on what this offering might include? What stage is it at in terms of commercialisation?

DDS: Ore sorting is one of the most exciting recent developments in our industry. With improvements in sensor capabilities and adoption of artificial intelligence (AI), this may well become the revolutionary change this industry needs to sustain itself in the face of diminishing grades and orebody quality.

EH: With our ore sorting solution development, we are targeting the ability to deliver complete offerings of hardware and sensor-fusion platforms as it relates to both bulk and particle ore sorting. These platforms would utilise AI to optimise the feed material for the downstream process. Metso Outotec is uniquely positioned to understand and optimise that plant feed stream with deep knowledge and almost complete technology coverage in both the concentrator and tailings processing areas.

We plan to bring new solutions to the market in the short term and continuously launch new technologies to increase capabilities and capacities when the developments are mature enough.

IM: Will these solutions leverage existing tools within the Metso Outotec product offering? Will they make use of existing agreements with other companies (for instance, the agreement with TOMRA that Outotec previously had in place)?

EH: Metso Outotec carries out its own development of these solutions, and some partnerships are part of it once sensoring and analysing different minerals and elements are not possible with a single or only a few technologies. Mining and concentration are becoming more and more a digital world where breakthrough innovation is finding its space towards efficiency and sustainable possibilities. Smart systems will enable improved equipment uptime, efficiency and remote diagnosis of process and maintenance, and will be the bonding element between our traditional offering portfolio and new technologies.

IM: Previously Metso has talked about the development of a bulk sorting solution: do these ‘AI-powered Ore Sorting Solutions’ fit into that category, or are they more particle sorting solutions?

EH: Bulk ore sorting enables material selection at high throughput flows and particle technology is limited by capacity while bringing the benefit of high accuracy on selectivity.

RK: Bulk sorting is in its early stages in industry and no single sensor can determine minerals content across all ore types and mine sites. This is where AI algorithms play a significant role in ‘self-learning’ ore characteristics, mine site by mine site. It also provides great opportunities to do sensor fusion and more accurately determine the minerals content based on outputs from various sensors and sensor types. AI augments our expert’s tacit knowledge and provides a more reliable way over time to analyse big data generated from online mineral analysis.

IM: Where in the flowsheet do you envisage these solutions going?

EH: The earlier we can remove the gangue from the flow stream, the better our energy efficiency will be by reducing the volume of waste material that is processed by downstream equipment. Deposits in advanced development allow for in-pit backfill bulk ore sorters that may be deployed behind mobile in-pit crushers, or before the coarse ore stockpile where backfilling is not an option. There are several pre-concentration technologies that can be applied at each stage of mineral processing and the ideal operation should combine those tools to remove the liberated gangue at multiple stages of the processing plant in order to achieve the most sustainable process (ie bulk/particle ore sorting, selective breakage, coarse flotation).

IM: Will the benefits of your solution be felt beyond the crushing and grinding stage? Do you intend to use the data generated from the ore sorting solutions to benefit the whole downstream flowsheet?

DDS: One of the benefits of ore sorting is more efficient removal of waste from the process feed. Under certain circumstances, this also means removal of deleterious material which otherwise would adversely affect downstream process performance such as flotation recoveries. In these cases, the downstream benefits are intrinsic. The key would be understanding the geometallurgical mapping of all rock types and their mineralogy, so a philosophy of ‘include or reject’ can be applied on a metallurgical response basis. This mapping can be improved with SmartTag™ and GeoMetso™ technologies from Metso Outotec.

EH: The ability to sort, the geometallurgical mapping and metallurgical response obviously feed back into the block model and allow for more options in the mine plan and life of mine resource recovery, for example with the deployment of low-grade stockpiles. This further enhances the sustainability of the mining operation.

IM: Is the market ready for and receptive to such a powerful ore sorting solution?

DDS: As we all know, for good reason, our industry is full of early adopters rather than innovators. Most operations will need to see the technology succeed elsewhere before increasing their uptake of the technology. The initial implementation will likely occur in partnership with customers whose operations need this technology to be economically viable.

EH: The key is to understand the ore variability through the deposit and through the life of mine. Adopting ore sorting as an integrated processing step does not differ that much from testing and sizing flotation circuits, where small changes in ore properties can affect the overall recovery. It is important to understand these changes and how to react to them during operations.

The confidence level in sensor-based ore sorting testing will grow over time. We already see real-life examples where customers report on ore reserves based on lower cutoff grades due to ore sorting.

IM: Anything else to add?

EH: Despite the fact that the concept of ore sorting, and the sensors required to detect the valuable ore from the waste, have existed for several years, if not decades, the implementation of these systems in full-scale operations have been relatively restricted to particular cases with the right kind of orebody to make the process viable. Implementing ore sorting more broadly remains the challenge and requires the dual application of the right sensors working effectively with the right mechanical handling systems to detect and remove the waste stream efficiently and accurately. The skills required to solve these challenges are not just for the traditional mining and mineral processing engineers, but need to include a cross-disciplinary team addressing the issues from all angles.

This Q&A interview was carried out as part of the IM March 2021 annual ore sorting feature, to be published early next month

ValeOre Metals considering Platsol, Falcon separator, Steinert ore sorting for Pedra Branca

ValeOre Metals Corp’s Pedra Branca platinum group element (PGE) project, in north-eastern Brazil, looks increasingly like leveraging the Platsol™ high temperature pressure leaching process judging by the latest test work.

Metallurgical results from sample material collected from outcrops at the Trapia and Curiu deposits areas at Pedra Branca for two preliminary Platsol tests conducted at SGS Lakefield, Ontario, have shown recoveries of 93.4-93.6% for palladium and 95.3-95.7% for platinum were achieved.

The company now plans two additional Platsol tests, to be performed by SGS, to determine the effects of adding elemental sulphur to the autoclave to optimise conditions required for PGE and gold recoveries, it said.

Platsol is a high temperature (>200°C) pressure leaching process designed to recover PGEs, gold and base metals. It has been shown to be particularly effective with PGE ore feeds characterised by high concentrations of chromium and low concentrations of sulphide, much like Pedra Branca, according to ValeOre Metals. The PGEs and gold are solubilised as chloro-complexes by the addition of chloride salt to the autoclave, while base metal sulphides are oxidised to form soluble metal sulphate complexes. The precious metals can be recovered directly from the autoclave discharge slurry by carbon absorption, or by precipitation with sulphide ions.

Platsol consists of standard, proven traditional technologies that are in use in mines around the world, according to the company.

The Platsol tests are part of a comprehensive mineralogical evaluation ongoing at SGS to characterise the speciation of palladium and platinum in Pedra Branca mineralisation to guide future process optimisation initiatives.

As part of this, the company is continuing with Falcon Ultrafine gravity separation test work as a potential pre-concentration circuit to upgrade feed material and improve mass pull.

The company has also initiated hot cyanide leach test work to assess the recovery rates of palladium, platinum and gold in a cyanide leaching process, and will shortly commence shipment of 100 representative chip samples from historic drilling at the Esbarro deposit to Steinert’s facility in Minas Gerais, to evaluate the potential of sensor-based ore sorting test work.

ValOre’s Chairman and CEO, Jim Paterson, said: “The pace of success at Pedra Branca has increased dramatically in the last three months, including today’s release of PGE metallurgical recovery rates of in excess of 93% for palladium and 95% for platinum using the Platsol process.

“Together with an aggressive property-wide exploration program, we are now focused on rapidly optimising the conditions, procedures and processes to further maximise the upside potential of the Pedra Branca project.”

Kalgoorlie-Boulder Mining Innovation Hub uncovers a fraction of processing value

Extensive testing conducted by a Kalgoorlie, Western Australia-based research hub has found Western Australian Goldfields mine sites can add value to their operations by focusing on small size fractions.

In recent decades, the primary driver to maximise profitability of mining operations has been to mine and process as much material as possible to exploit economies of scale. This has led to bigger equipment, higher throughput and greater production, but not necessarily efficient use of resources.

With the concerns of declining grades, more complex orebodies, greater haulage distances, higher energy costs and water usage, any approach that can alleviate the impact of these issues is highly desirable.

The Kalgoorlie-Boulder Mining Innovation Hub recently explored use of a pre-concentration technique known as “Grade by Size Deportment”.

“This technique exploits the propensity for some ores to exhibit preferential breakage leading to concentration of minerals in specific size fractions,” it explained.

Several sites within the Goldfields region of WA showed significant potential for separation by size to provide value to their operations, according to the hub. This is particularly the case where either marginal grades are present or growing distances from face to surface, or, from mine to mill, are subject to increasing transport costs, it said.

Research and test work by the hub show that natural grade by size deportment during coarse rock breakage and screening is a key lever for generating high-value coarse separation, it said. This, in turn, can drive better productivity and returns for mine operators.

The Kal Hub, established in 2018 by the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), enables focused collaboration between researchers; mining equipment, technology and services suppliers; and mining companies to unlock value for Australian mining through technology development.

CRC ORE Chief Operating Officer, Dr Luke Keeney, said: “In a short amount of time, the hub has been able to bring together some of the most innovative people in industry and research, enabling collaborative innovation to occur.

“This collaboration is good for the Goldfields, and for the wider mining industry, as it demonstrates the benefits mine sites can experience by deploying various aspects of Grade Engineering®, including grade-by-size deportment.”

Grade Engineering is a system-based methodology developed by CRC ORE designed to reject low value material early in the extraction value chain and pre-concentrate processing plant feed. A key lever for successful Grade Engineering is grade-by-size deportment, the hub said.

The Kal Hub Technical Advisor, Dr Laurence Dyer, said the objective of the Grade-by-Size Deportment project was to undertake initial representative sample testing to determine natural deportment Response Rankings at a range of deposits in the Kalgoorlie-Boulder region.

“This project provided an introduction for industry participants to Grade Engineering and an indication of potential opportunities that grade-by-size deportment may present,” Dr Dyer said.

“A number of companies came on board and we were able to obtain diamond drill core and reverse circulation (RC) drilling samples from a variety of sites in the Goldfields to crush, screen and assay to develop a snapshot of responses to this approach.”

Samples were crushed where necessary and screened into up to six size fractions, with a finer set of screens used for the RC samples to accommodate the difference in particle size distribution.

As expected, gold sites displayed significant variation in response, while all nickel sites tested showed significant upgrade in the finer fractions of both nickel and cobalt, the hub said.

“RC samples were a compelling sample option due to their prevalence and self-preparation for screening, however there remains a question as to the legitimacy of the results they generate,” it added.

Dr Dyer said: “Gold samples produced varied data with the majority of sites producing low to moderate upgrades on average.

“The RC samples generated greater variation and often decreased in grade at the finest size fractions, likely due to particles being below liberation size, creating issues with the response ranking fit.”

The Kal Hub research also showed nickel produced far more consistent behaviour with all sites producing moderate to high responses for both nickel and cobalt. While for some samples the nickel and cobalt response rankings matched well, in others, the nickel upgraded significantly better, it said.

Thermo Fisher Scientific joins CEEC communication hub

The addition of new industry sponsors is enabling the Coalition for Energy Efficient Comminution (CEEC) to gain greater traction in leading change and driving the uptake of more energy and water efficient, lower impact mineral processing, it says.

CEEC said this after recruiting Thermo Fisher Scientific, a world leader in supplying solutions for efficient and sustainable mining, as a sponsor of the global not-for-profit communication hub.

Employing more than 75,000 people globally, Thermo Fisher Scientific operates through four segments: Life Sciences Solutions, Analytical Instruments, Specialty Diagnostics, and Laboratory Products and Services. The company provides weighing, monitoring and sampling systems and applications expertise to help optimise process control, production monitoring and automation in mining and bulk material handling.

Thermo Fisher Scientific Field Marketing Manager, Scott Ferguson, said the company’s mission “to make the world healthier, cleaner and safer” was very much in alignment with CEEC’s vision for more efficient, lower footprint mining.

Following extensive analysis of client needs, and a solid investment in research and development, Thermo Fisher is expanding its suite of sorting and pre-concentration products for the minerals sector, according to CEEC.

In response to renewed interest in pre-concentration processes, Thermo Fisher Scientific has launched its cross belt analyser, CB Omni Fusion, using prompt gamma neutron activation analysis into bulk ore sorting applications.

The company also released a new particle size analyser (PSM-500) in June 2020 – specifically designed for comminution circuits.

“The ability to measure product out of the grinding circuit in real time can have very large benefits,” Ferguson said. “By optimising grinding control systems, operators can maximise throughput, use energy more effectively and achieve greater recovery.

“This analyser draws upon proven technology and incorporates an interactive user interface and improved reliability,” he said.

Thermo Fisher Scientific has been supplying slurry samplers, in-stream analysers and cross belt analysers for more than 40 years, CEEC explained.

CEEC CEO, Alison Keogh, said Thermo Fisher Scientific was a welcome addition to its list of valued sponsors from around the globe.

“We’re proud to partner with companies that provide solutions for efficient and sustainable mining,” Keogh said. “These relationships open the door to wider awareness and adoption of new technologies and processes that positively impact the industry.

“This support from Thermo Fisher Scientific, in conjunction with our other sponsors, helps CEEC continue its important global work of providing free and impartial online resources and low cost events that highlight best practice and emerging advances in profitable, eco-efficient mineral processing.”

Ore sorting has role to play in ‘Green Mining’ developments, TOMRA says

TOMRA says its advanced sensor-based sorting technologies can provide mining operations with the energy efficiency and ore recovery benefits they require to reduce their environmental footprints.

The ability to recover valuable ore from even sub-economic deposits or dumps has become increasingly relevant as the energy-intensive mining industry shifts towards a ‘Green Mining’ approach, according to the company.

Tord Svensson, TOMRA’s Head of Sorting Mining, explains: “For a mining company to become more sustainable and profitable, it requires a shift in focus that places more value on potentially limited commodities like water and ore.

“To achieve an environmentally-focused and efficiency-oriented production process – which is integral to Green Mining – it is necessary to implement solutions right from the beginning of the process. This is where ore sorting equipment comes in: using these technologies in the early stages of mining reduces waste material and shrinks the carbon footprint, while increasing profitability.”

TOMRA is a pioneer of sensor-based sorting technologies, offering smart technologies for sorting and separating a variety of valuable substances. Its solutions range from industrial mineral processes to sorting gemstones, ferrous and non-ferrous metals, coal and other fuels and slag metal.

The sensor-based sorting technology not only significantly reduces the amount of energy and water required, compared with more traditional methods such as grinding and dense media separation, but also maximises the efficiency and quality recovery of valuable ores, according to TOMRA.

X-ray transmission (XRT), one of TOMRA’s leading solutions, separates dry material of various ore and minerals based on their atomic density, irrespective of surface properties and thickness. This means it is not necessary to crush or grind every rock into smaller particles, which results in massive savings of energy, water, and their related costs, according to the company.

“Considering that grinding is the most energy-intensive part of the production cycle, as an estimated 50-75% of the energy used in mining is for the liberation and comminution of ore and minerals, this technology can have a significant impact on the sustainability and profitability of a mining operation,” TOMRA said.

Pre-concentration techniques like sensor-based sorting are proven to reduce energy consumption by about half, resulting in a considerable reduction of the CO2 footprint and providing a highly cost-effective solution, the company added.

TOMRA has created a Green Counter on its website that displays the total amount of CO2 reduced through the use of its sorting machines in real time. It uses the smart technology within the equipment, which records the amount of rock sorted and eliminated, as well as throughput and total hours of operation.

“With this data, TOMRA and mining companies are able to calculate the energy in kWh saved by not treating the waste which has been removed by the sorters,” the company said. “The amount of energy saved is converted into CO2 equivalents, which in turn are converted into CO2 metric tonnes.”

Through the use of TOMRA sorting machines, client companies have saved 123,696 t of CO2 in 2018 alone, the company said.

The company concluded: “TOMRA’s sorting solutions have proven to be more than just technological innovation – they are also considered the benchmark for industry standards in both efficiency and sustainability. TOMRA remains committed to evolving its technology with a clear focus towards preserving our shared natural resources.”

Granada Gold Mine brings Gekko in for “disruptive” pre-concentration tests

Toronto-listed Granada Gold Mine thinks pre-concentration by separation has the potential to lower capital and operating costs at its Granada gold project in Rouyn-Noranda, Quebec, Canada.

The company has come to this conclusion after receiving higher grades during testwork, which, it said, “may have implications for the grade of future mill feed, the size of the gold deposit, and the costs associated with future mine production.”

The company went to Gekko Systems of Ballarat, Australia, for this testwork. Granada said of Gekko: “Their innovative pre-concentration system increases recovery values, reduces ore mass and waste, reduces water use, lowers power requirements, and improves feed rates, all potentially meaning lower capital and operating costs for Granada along with higher recovery rates.”

A 260-kg sample of low-grade drill core assaying 0.6 g/t was upgraded to 6 g/t with a 60% overall recovery by this work. The Gekko laboratory processed the sample by crushing through different size fractions, homogenised, and split according to standard lab practices, Granada said. Gravity tests were conducted on coarse and fine fractions, approximately +600 μm and -150 μm, respectively.

A grade of 21 g/t Au was achieved from the coarse size fraction, with a recovery of 40%, resulting in an upgrade ratio (concentrate/feed) of 35.

Frank Basa, Chairman and CEO of Granada Gold, said: “As a result of this preliminary work, we believe that employing disruptive technologies on lower-grade ore to pre-concentrate the mineralised material for process plant feed can be advantageous. This approach can be used to evaluate the potential to increase the gold resource and other recoverable metals which, in turn, will lower project capital and operating costs.”

In a related matter, the company has also begun a test programme using the pilot plant of its sister company, Canada Cobalt Works. In this first round of tests, a 120-kg sample of low-grade mineralised rock from the Granada gold mine waste dump was processed by screening the material into three screen sizes followed by gravity separation. These concentrates were then analysed for gold, silver, cobalt, nickel, and copper.

Gravity assay test results are pending, with a particular focus on recoverable base metals.

The current feasibility study for the on-site gold mine and plant at Granada has been put on hold pending results of the metallurgical studies. The environmental studies to install a 600 t/d gravity leach plant are, in the meantime, ongoing at the Canada Cobalt Works Castle mine. The flowsheet has been completed and equipment has been sourced, the company said.

The company is in possession of all permits required to commence the initial mining phase, known as the “Rolling Start”, which allows the company to mine up to 550 t/d, capable of producing up to 675,000 t of ore over a three-year period.