Tag Archives: XRF

Gekko Systems releases Mark 6 Carbon Scout sampling system for CIL, CIP plants

The team at Gekko Systems has announced the release of its next-gen Mark 6 Carbon Scout solution.

The Carbon Scout is a self-contained, ground-level sampling system that measures the pH, dissolved oxygen, slurry density and gold concentration in carbon-in-leach (CIL) and carbon-in-pulp (CIP) circuits. An important new feature is the optional X-ray Fluorescence sensor to measure gold on carbon for real-time gold circuit inventory.

The self-contained device collects slurry samples from CIL/CIP tanks to determine the concentration of the activated carbon in the pulp for each tank, to an accuracy of ±0.5 grams of carbon per litre of pulp, Gekko claims. The concentration levels are then used to automate carbon movement to optimise the carbon distribution.

Gekko said: “The Carbon Scout benefits sites by providing real-time data which allows operators to significantly reduce soluble gold loss from the circuit by providing advanced measurements ahead of any unwanted excursions. The Carbon Scout also allows for automation of the carbon movement, minimising exposure to hydrogen cyanide gas and reducing the need for manual handling of samples.”

Constructed from stainless steel, the ground-level system enhances operator efficiency by removing the need to undertake time consuming manual sampling and provides a single point sampling station to improve accuracy and increase safety, according to the company. The automation of carbon movement, meanwhile, increases the efficiency of the process, ensures carbon inventory set points are achieved and reduces the need for operator, metallurgist and other processing staff input.

Some of the sites to have installed the Carbon Scout solution include Gruyere in Western Australia (pictured above on the left with the Gekko OLGA on the right) and Ity in Cote d’Ivoire.

The solution was commercially released in 2017.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Credit: Engels Trejo, Manager Technical Services, Hudbay Peru

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

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

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

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

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

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

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

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

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

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

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

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

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

Southern Innovation set for exploration scanning, ore sensing growth with Russell appointment

Southern Innovation, a developer and manufacturer of state-of-the-art real-time materials analysis equipment for the global mining industry, says it has taken a strategic step forward in sales and marketing with the appointment of Steve Russell as Head of Sales and Business Development.

Russell, currently Director of Mining at Scott Automation & Robotics, joins the Southern Innovation team in mid-January 2022 in a role that is expected to drive growth in the company’s key areas of rig-mounted exploration scanners and conveyor-mounted ore sensing/scanning, especially in bulk ores, and looking to near-term applications in base and precious metals.

An engineering professional with a strong background in mining as well as sales and marketing, Russell has previously driven several step-change innovation and automation strategies in the mining industry, according to Southern Innovation.

Southern Innovation, Managing Director David Scoullar, said this appointment will drive strategic growth that has been in the planning stage for a considerable time.

“Southern Innovation has a solid and conservative business base, built off a unique foundation of robust, patient and home-grown development of much-sought-after signal processing technology,” he said. “We have worked closely with some of the most respected and sizeable international mining companies in R&D, and we are now confidently transitioning to grow product sales.

“Our clear objective is to help our customers to improve productivity as well as reduce waste in minerals identification, extraction and processing as the industry drives to net zero emissions by 2050.”

Southern Innovation’s key proprietary products are known as DrillScan™ and GradeScan™.

DrillScan (pictured above, working in the Pilbara of Western Australia) was developed in close collaboration with BHP and is an X-ray Transmission scanner that bolts onto the drill chain of RC drill rigs, performing accurate and continuous analysis while drilling. Results from field use demonstrate more than 95% correlation between continuous, real-time analysis and post-drilling XRF lab-based grade analysis of contemporaneous samples, according to the company.

GradeScan™, meanwhile, is an online, real-time conveyor-mounted X-ray scanner capable of characterising sampled bulk ore in real time at 1 mm resolution across multiple dimensions, according to the company. It features full spectrum scanning, enabled by Southern Innovation’s patented digital signal processing technology, SITORO® Accelerated Analysis.

Evaluate ore sorting options at prefeasibility study stage, TOMRA’s Rutledge says

TOMRA Mining is making a case for its sensor-based ore sorting solutions to be evaluated earlier in the mining project evaluation phase, with Jordan Rutledge, Area Sales Manager, arguing that consideration of its use at the very beginning of flowsheet discussions can influence up- and down-stream equipment selection.

The company’s sensor-based ore sorting systems have spread across the mining sector, migrating from industrial minerals and diamond operations to base and precious metals.

Speaking at a sensor-based sorting seminar in Toronto, Canada, held late last month, Rutledge (pictured) said the use of the technology needed to be considered early in the mine development scope in order to leverage the most benefit for the operation.

“Sensor-based sorting should be considered in the flowsheet from the beginning and evaluated in prefeasibility studies to see if it is suitable for the project and will add value to the plant,” she said.

“In many cases, sorting works really well and, as we continue to go towards a green economy, the use of our resources is vitally important. In order to make the best use of them, sorting plays a critical role.”

Rutledge, an event organiser and presenter, joined 40 participants from across Canada at the seminar, which included representatives from miners such as Agnico Eagle, Capstone Mining and Cheetah Resources; from laboratories such as testing and certification company SGS and the Saskatchewan Research Council ; from engineering companies such as DRA Global, Primero, CIMA and Halyard; and students from the University of Toronto.

“The event highlighted the important role of sensor-based sorting technologies in green mining and their potential to unlock significant value in mining projects, as well as the possibilities of digitalisation for supporting customers and managing connected equipment,” TOMRA said.

Intertek opens state-of-the-art new laboratory in Western Australia

Intertek Group has officially opened its new Minerals Global Centre of Excellence, in Perth, Western Australia, bringing with it world-class technical expertise, automated technology, and pioneering innovation and services, Intertek CEO, André Lacroix, says.

The Centre of Excellence is the largest Intertek Minerals laboratory in the world and consolidates the group’s Minerals business into a 20,000 sq.m, multi-service, facility housing over 500 employees. It is powered by the latest pioneering technology to deliver a broad range of Assurance, Testing, Inspection and Certification (ATIC) services to the industry, according to Intertek.

The new centre was officially opened at an event attended by Hon Bill Johnston, Western Australia’s Minister of Mines and Petroleum.

Intertek said: “COVID-19 has intensified the world’s focus on innovative and sustainable mining practices as industries seek to Build Back Ever Better. From the steel required for the construction of wind turbines to the nickel fuelling the shift to electric vehicles, responsibly sourced commodities underpin a cleaner, more sustainable and technologically advanced future. In order to meet the needs of a growing global population while reducing greenhouse gas emissions, a variety of energy sources and commodities will be needed to power the modern world.”

Intertek’s Minerals business has, for many years, driven innovation and sustainability throughout the resource supply chain, from exploration and resource development, through to production, shipping and commercial settlement, supported by a global network of experts and a customer-centric local delivery model, it said.

“As a purpose-led company, Intertek’s mission is to make the world a better, safer and more sustainable place and these values lie at the heart of the Minerals Global Centre of Excellence, which will feature 3,030 x330 W solar panels, making it one of largest rooftop solar installations in Western Australia,” the company said.

The facility will provide miners with access to global specialists in mineralogy, XRD, XRF, FTIR, ICP and statisticians, alongside a new technology and innovation hub with world-class technical expertise and superior customer service at its core, it said.

It will also include eight robotic automated systems, including sample preparation, XRF and wet chemistry systems.

Demonstrating its commitment to investing in advanced technology, Intertek has installed two Chrysos PhotonAssay units at the Minerals Global Centre of Excellence. These units show Intertek’s unwavering focus on leveraging innovation and will provide clients with more accurate and environmentally friendly analysis of gold and complementary elements, it said.

“The need for creative solutions is becoming ever more critical to solving today’s biggest energy and infrastructure challenges,” the company said. “True to its pioneering spirit, Intertek is constantly evaluating new instrumentation and technology to continuously improve quality, safety and efficiency and deliver value for our customers. The new Centre of Excellence shows Intertek’s unwavering focus on leveraging innovation and its commitment to providing clients with industry-leading, high quality analytical data.”

André Lacroix, Chief Executive Officer of Intertek, said: “The world has reached a tipping point in terms of sustainability and it is the movement of our time. As all industries seek to Build Back Ever Better, responsibly sourced commodities today will form the building blocks of a cleaner, greener, more sustainable tomorrow. This exciting new facility will provide our customers with instant access to world-class technical expertise, automated technology, pioneering innovation and services, all in one location.

“With a strong focus on technical excellence, data analytics and superior customer service, we will help the world’s leading mining companies accelerate to a sustainable future by Unearthing Xcellence, in turn enabling us to fulfil our mission of making the world a better, safer, more sustainable place for all.”

Intertek Minerals provides mineral testing services throughout the mining life cycle from exploration geochemistry, mine site laboratory services, minerals inspection, sampling and analysis, robotic laboratory solutions, environmental services and metallurgical testing services across the mining supply chain.

New Gold to collaborate with MineSense in underground ore sorting move

MineSense is gearing up for a move underground with the help of New Gold and its New Afton gold-copper mine in British Columbia, Canada.

The Vancouver-based technology company has already established and proven its ShovelSense technology for the open-pit mining sector, with its X-ray Fluorescence (XRF) sensor-based system now operating on shovels, wheel loaders and excavators on a commercial basis across six operating mines. This includes large installations at Teck’s Highland Valley and Copper Mountain’s copper operations in BC, as well as one ShovelSense unit at the Antamina copper operation in Peru.

Designed for operation in extreme environments and retrofits on any existing mobile equipment, ShovelSense units come equipped with a human machine interface and proprietary algorithms that measure and report ore grade/characteristics. They can also connect directly to fleet management or other existing control software systems, enabling mine operators to reconcile geological block models with actual ore grade data.

Having finetuned the system for above-ground operations, the company is now embarking on its underground move, according to MineSense President and CEO, Jeff More.

A trial of the underground ShovelSense system at New Gold’s New Afton mine is first up to complete product development. The company will be installing a unit on a Cat R1600G LHD for this step. This will be followed closely by installation at a “large entity” in Chile – with More anticipating start up in the September or December quarter.

The development agreement with New Gold at the BC-based mine is looking to trial and finetune the system for underground operations, with More confident the ShovelSense system will stand up to the test.

“The core technology – all of the algorithms, software, hardware – is the same as ShovelSense for open-pit mining,” More said. “It is the ‘application package’ – looking at how we can attach the unit to the machine and protect it in an underground environment – that is what we have to test out. The design for this is already complete; it’s just a matter of trialling it.”

New Afton represents a good test for the system.

New Afton is Canada’s only operating block cave mine, with the New Afton deposit part of a larger copper-gold porphyry district in the region. The operation regularly mines 15,000-16,000 t/d of ore and waste, with the majority of this currently going to the mill.

The company has already pursued “ore segregation” projects to boost the grade of material being fed through to the processing side, but the move into the higher-grade C-Zone in 2023-2029 will place an even greater emphasis on ore/waste boundaries and milled tonnes at the operation.

At the same time, the ShovelSense deployment at New Afton will represent the first time MineSense has sent a unit into a mine that has so much payable gold, with most operations the company has worked on being primarily base metal-oriented.

In 2020, New Afton produced 64,000 oz of the yellow metal, along with 32,659 t of the red metal.

“This will be the first time we’re touching gold at this level; we have other mines that have payable gold but not at that level,” More explained.

In New Afton’s case, sampling and historical data has proven that the orebody’s copper and gold ratios tend to be consistent and unchanging over the long term. With this knowledge, New Afton has used technology in the past to determine the copper value and make ore/waste production decisions. ShovelSense allows New Afton to move the ore/waste production decision to the drawpoint, according to MineSense. This reduces mixing and blending during the crushing and conveying circuit which can homogenise the material to the point where it is not worth segregating.

Trialling new technology such as this is nothing new for New Afton.

The operation already uses automated loading through Sandvik’s AutoMine solution, is employing electrification with the use of Sandvik and MacLean Engineering battery-powered mobile equipment, and, in the process plant, has Gekko Systems’ highest volume InLine Pressure Jig IPJ3500 to improve gravity concentration.

More says the ShovelSense unit could be in the Cat LHD bucket at New Afton in August, with the machine then going through an above-ground trial ahead of the underground transition at the end of September.

“By early Q4, we should have completed the pilot,” he said.

COREM, Steinert ore sorting tests present opportunities for Cartier at Chimo gold project

Cartier Resources says ore sorting tests carried out by COREM and Steinert US on mineralised samples from the Chimo Mine property, in Quebec, Canada, have indicated gold grades could increase substantially with the use of the pre-concentration technology.

Gold from Chimo is present in two types of mineralised facies: i) quartz veins with coarse visible gold grains having an affinity for the gravity concentration of gold at the mill and ii) zones of silica-rich mafic rocks associated with non-refractory arsenopyrite having an affinity for the flotation of a concentrate of arsenopyrite for gold recovery at the mill.

To perform the sorting tests, rocks representative of the two mineralised facies, made up of the following six mineralogical facies, were first selected for static recognition of each of the facies by the sensors of the sorter:

  • Gold-bearing quartz veins;
  • Gold-bearing silica;
  • High grade gold-bearing arsenopyrite;
  • Medium grade gold-bearing arsenopyrite;
  • Low grade gold-bearing arsenopyrite; and
  • Mafic waste rock.

The detection sensors of the industrial sorter at COREM in Quebec, Canada, were the RGB camera using the optical properties of reflection, brightness and transparency to locate quartz and silica and the X-ray Transmission sensor using the volumetric property of atomic density to locate arsenopyrite. The two sensors adequately recognised the six mineralogical facies associated with the mineralisation, with dynamic calibration tests of the sorter with the moving conveyor making it possible to sort, one at a time, 2 kg samples of each of the facies, Cartier said.

The results of this first test at COREM showed the first three sorts (on a total of eight sorts) concentrated 99.1% of the gold contained in 44.4% by mass of material mass for a grade of 56.3 g/t Au, representing a percentage increase of 223% in gold content over sorter feed. The reject, representing 0.9% by mass of material, contained only 0.4 g/t Au.

The sorter was then ready to perform sorting tests on the 105.7 kg production sample, representative of the mineralised facies at an average grade of 2.16 g/t Au. This content was obtained by including 20% by mass of material with zero grade of gold, simulating dilution in the stopes. COREM’s sorting plan separated 53.9% by mass of the material in the form of a preconcentrate at an average grade of 3.68 g/t Au, representing an increase of 170% in the gold grade compared with the sorter feed. The waste disposal, separated from the mineralisation, represented 46.1% by mass of material at an average grade of 0.38 g/t Au.

Sorting tests carried out with Steinert in Kentucky using a Steinert KSS FLI XT machine with XRT, colour, laser, and induction sensors yielded comparable results.

A 80.69 kg production sample, representative of the mineralised facies at an average grade of 2.13 g/t Au, to which 20% by mass of material at zero grade of gold was added mathematically, representing the dilution in the workings, was used for testing. The new calculated diluted grade was 1.55 g/t Au.

Calculation of the results revealed that 51% by mass of the dilute grade material could be separated as a preconcentrate at an average grade of 2.72 g/t Au, representing a 175% increase in gold grade compared with the sorter feed. The waste disposal, which would be separated from the mineralisation, would represent 49% by mass of material at an average grade of 0.36 g/t Au.

Sorting tests with COREM were carried out following these tests to validate that the 20% of dilution material at zero grade of gold, mathematically added, could physically be effectively separated by the sorter, Cartier said.

The sorting tests carried out by both COREM and Steinert US were comparable, with these results providing prospects for increasing the value of the resources with ore sorting technology.

The objective of the industrial sorting of the mineralisation is to increase the grade of the preconcentrated material preceding the milling operations, which allows an increase in the recovery rate at the mill, reduces transport costs to the mill, reduces milling costs, reduces the costs of environmental restoration of mine tailings, and reduces the environmental footprint of mine tailings and, consequently, increases the social acceptability of the mining project, Cartier said.

The most recent resource estimate from Chimo included 6.6 Mt at an average grade of 3.21 g/t Au for a total of 684,000 oz of gold in the indicated category and 15.2 Mt at an average grade of 2.77 g/t Au for a total of 1.36 Moz of gold in the inferred category.

The Axora take on crushing and comminution

As we are continually told, comminution is one of the most energy intensive single steps in the resource extraction business.

One estimate is that it accounts for 36% of all the energy used in the extraction of copper and gold, which is only a shade over the 30% proposed as an average by another industry expert for all mining and mineral processing industries.

It also accounts for an estimated 3% of the global energy requirement for metal production.

These energy requirements are shocking from a sustainability and greenhouse gas emission perspective; they are also extremely costly regarding operating expenses on site.

It is with this in mind that IM touched base with Joe Carr, Industry Innovation Director of Mining at Axora.

A spinoff from the Boston Consulting Group, Axora has emerged as a business-to-business digital solutions marketplace and community for industrial innovators. It says it allows industrial companies to discover, buy and sell digital innovations and share knowledge in its community, powered by an advanced marketplace.

“We exist to transform industries to be digital, safer, more sustainable and efficient,” the company states on its website.

Having recently gone to press with the annual crushing and comminution feature (to be published in the IM April 2021 issue), IM spoke with Carr to find out what the Axora marketplace has to offer on the comminution and crushing front.

IM: What are the main issues/concerns you continuously hear from your mining clients when it comes to designing and maintaining comminution circuits? How many of these problems/issues can already be solved with existing technology/solutions?

JC: One of key issues in this area we hear from our customers at Axora is the blending quality of the input ores.

Joe Carr, Industry Innovation Director of Mining at Axora

This could be particularly relevant in the sulphide space, for instance.

I did some work years ago on Pueblo Viejo for Barrick. When I was there, one of the things we were working on was blending the sulphides as we were feeding the mill from numerous satellite pits with very different sulphide grades. Because we were processing the ore with an autoclave, high-grade sulphides would cause a temperature spike and the low-grade sulphides would lower the temperature. This constant yo-yoing of the feed into the autoclave was terrible for the recovery of metals against the plan.

Generally, the old school way of blending is setting up stockpiles of ore based on whatever variable you want to manage at your operation. You would put a defined amount of each into the primary crusher on the understanding this would create a ‘blended’ feed for the processing plant.

With the information we have at our fingertips today, this process seems outdated.

You could, for example, use HoloLens or another VR system in tandem with the shovel operator to be able to see exactly what material he or she is excavating. That can then be linked back to the geological block model, with this material then tracked in the trucks and onto the run of mine stockpile, before heading to the plant.

This is where something like Machine Max comes in. Machine Max is a bolt-on IoT sensor that tracks where your trucks are in real time – where they have been and where they are going. The processing piece requires block model integration into a mine plan system. If you have the building blocks in place – the networking, sensors, additional infrastructure, etc – Machine Max could, when integrated with this model, allow you to attempt real-time ore tracking.

“If you have the building blocks in place…Machine Max could, when integrated with this geological block model, allow you to attempt real-time ore tracking,” Joe Carr says

The issue is not that the technology doesn’t exist, but that the mining industry hasn’t yet cracked putting all of this together at an industry-wide scale, available to all miners.

You can carry out a project like this or go totally the other way and have a machine-learning or artificial intelligence algorithm in the plant that is constantly reading the incoming feed. These could be based around the block model inputs, or a digital XRF solution, which is able to constantly tweak or adjust the plant settings to the feed specifications. Process plants are generally setup to handle one type of feed. This is usually only tweaked in retrospect or for short periods of time when the mine plan moves into a different mining horizon.

We also have a comminution solution that understands the feed coming in and optimises the mill and power settings to get the optimal grind for flotation, maximising recovery at the back end. While the input is typically set up to be grind quality and hardness for optimal flotation, there is no reason why you couldn’t configure it for, say, sulphides going into an autoclave, tweaking the autoclave heat settings dependent on the feed.

Once that system is set up, it becomes a self-learning algorithm.

Saving operational costs is another pain point for mining companies we always hear about.

We have a solution on our marketplace from Opex Group, which is looking to optimise production while reducing power. Coming from the oil & gas space, this AI algorithm, X-PAS™, offers the operator an opportunity to adjust the settings while still achieving the same required outputs. This is tied to CO2 reduction, as well as power cost reductions.

Opex Group’s AI algorithm, X-PAS, offers the operator an opportunity to adjust the plant settings while still achieving the same required outputs

In mining, the plant is your largest drawer of power, hands down. Generally, if it is not powered on the grid, it is powered by diesel. Opex Group’s solution can save up to 10% of power, which is a significant amount of fuel and CO2.

The solution reads information from your pumps and motors, analyses the planned output of your plant using all the sensor feeds, and tweaks the variables while sustaining the required output. The algorithm slowly learns how you can change configurations to reduce power, while sustaining throughput. This results in lower power costs, without impacting the output.

Importantly, instead of automating the process, it offers the saving to the operator sat in the control room. Operators, in general, are incredibly reluctant to pass over control to an AI algorithm, but when faced with such power saving opportunities, they will often elect to accept such a change.

And, of course, plant maintenance is always on the agenda.

This is where Senseye, which has been used in the car industry by Nissan and the aluminium sector by Alcoa, is useful.

Essentially, this provides predictive maintenance analytics. It is also a no-risk solution with Senseye backed by an insurance guarantee. It is sold on the basis that if you do not earn your money back within the first 12 months, you get an insurance-backed refund.

There could also be openings in the plant for Razor Labs’ predictive maintenance solution, which is currently increasing the uptime of stackers, reclaimers and car dumpers for iron ore miners in the Pilbara.

IM: When it comes to future comminution equipment design, do you expect digitalisation, wear liner innovations, or equipment design to have more of a bearing on operational improvements at mine sites? Phrased another way; is more emphasis being given to refining and extending the life of existing products with digital technologies and wear solutions, than the design of brand-new equipment?

JC: We believe there is always going to be a focus on retrofit and extensions. Once a mill is built, changing the equipment, upgrading, etc is very hard and time consuming. The logistics of getting a new SAG mill to site, for example, are mind boggling. New technology will always come for new sites, but most of the world’s mining capacity is already in place. I would expect most digitalisation to focus on two areas:

  1. Getting more and longer life from all the assets. For example, extending liner life, reducing operating costs and shortening downtime between refits; and
  2. Drawing insights from the existing asset with a view to sweating it. No mill ever stays at nameplate; there is always an increase in production. One or two percent more throughput can put millions onto the bottom line of a company. No mill wants to be a bottleneck in the cycle. In a mine there are always two goals: the mine wants to produce as much ore as possible to put the pressure on the mill, and the mill wants to run as fast as possible to put pressure on the mine.

When it comes to extending liner life, we have a solution worth looking at.

One of the companies we work with out of Australia has an IIoT sensor all tied to wear and liner plates. It is a sensor that is embedded into a wear plate and wears at the same time as the wear plate itself wears. It provides this feedback in real time.

So, instead of the standard routine changeout, it gives you real-time knowledge of what it is happening to these wear parts.

We have a great case study from Glencore where they installed the sensors for around A$200,000 ($152,220) and it saved several million dollars. The payback period was just weeks.

Where I want to take it to the next level is pairing the wear plate monitoring technology on chutes and ore bins and looking into SAG mills and crushers. Relining your SAG mill or primary gyratory crusher is a massive job, which takes a lot of time and cuts your productivity and output by a huge amount. Wear plates are made as consumables, so if you can use 5% less over the space of a year, for instance, there are huge cost and sustainability benefits. You can also more accurately schedule in maintenance, as opposed to reacting to problems or sticking to a set routine.

IM: When compared with the rest of the mine site, how well ‘connected’ is the comminution line? For instance, are gyratory crushers regularly receiving particle size distribution info for the material about to be fed into it so they can ‘tailor’ their operations to the properties of the incoming feed?

JC: Generally, not really. The newer, better financed operations tend to have this. Taking the example above, when designing a plant flowsheet, the close side settings are used. But are they updated on the fly to optimise the plant? Not really. Most processes are designed with a set number of conditions to operate at their maximum.

Most plants dislike, and are not set up to handle, variation in their system, according to Carr

Most plants dislike, and are not set up to handle, variation in their system. They like consistent feed quality and grade to achieve maximum recoveries. Over the next few years, the companies that develop the best machine learning or AI models to run plants in a more real time, reactive way will see the biggest growth. A mill will always say it’s the mine that needs to be consistent, but the nature of geology means that you can never rely on this. As one geologist I knew said, “geology, she is a fickle mistress”.

IM: Where within the comminution section of the process flowsheet do you see most opportunity to achieve mining company sustainability and emission goals related to energy reductions, water use and emissions?

JC: In terms of emissions, at Axora we are actively looking at technology that can help across the entire plant. There was a great paper published in 2016 around this specific topic ‘Energy Consumption in Mining Comminution’ (J Jeswiet & A Szekeres). The authors found that the average mine used 21 kWh per tonne of ore processed. Given diesel produces 270 g per kWh, this means a plant produces 5.6 kg of CO2 per tonne of ore processed, on average. For a 90,000 t/day site, this might represent 510 t of CO2 per day (186,000 t/y), just for processing. To put that into context, you would need 9.3 million trees to offset that level of carbon.

If the industry is serious about lowering its carbon footprint, especially Scope 1 and 2 emissions, then the focus has to come into the process. There are easy wins available from proven solutions in other sectors for companies that want to take them.

Anglo American Platinum’s modernisation drive to continue into 2021

Anglo American Platinum says it is looking to deliver the next phase of value to its stakeholders after reporting record EBITDA for 2020 in the face of COVID-19-related disruption.

The miner, majority-owned by Anglo American, saw production drop 14% year-on-year in 2020 to 3.8 Moz (on a 100% basis) due to COVID-related stoppages. Despite this, a higher basket price for its platinum group metals saw EBITDA jump 39% to R41.6 billion ($2.8 billion) for the year.

As all its mines are now back to their full operating rates, the company was confident enough to state PGM metal in concentrate production should rise to 4.2-4.6 Moz in 2021.

Part of its pledge to deliver more value to stakeholders was related to turning 100% of its operations into fully modernised and mechanised mines by 2030. At the end of 2020, the company said 88% of its mines could be classified as fully modernised and mechanised.

There were some operational bright spots during 2020 the company flagged.

At Mogalakwena – very much the company’s flagship operation – Anglo Platinum said the South Africa mine continued its journey to deliver best-in-class performance through its P101 program.

Rope-shovel performance improved to 26 Mt in 2020, from 15 Mt in 2019, while drill penetration rates for big rigs increased from 15 m/h, to 16.7 m/h. Alongside this, the company said its Komatsu 930E truck fleet performance improved to 298 t/load in 2020, from 292 t/load in 2019.

These were contributing factors to concentrator recoveries increasing by two percentage points in 2020 over 2019.

During the next few years, the company has big plans to further improve Mogalakwena’s performance.

In 2020, the mine invested R500 million in operating and capital expenditure, which included commissioning a full-scale bulk ore sorting plant, coarse particle rejection project and development of the hydrogen-powered fuel-cell mining haul-truck (otherwise referred to as the FCEV haul truck).

First motion of the 291 t FCEV haul truck is still on track for the second half of 2021, with the company planning to roll out circa-40 such trucks from 2024.

Anglo Platinum said the bulk sorting plant (which includes a Prompt Gamma Neutron Activation Analysis and XRF sensor-based setup, pictured) campaign at the Mogalakwena operation is due to end this quarter.

The company’s hydraulic dry stacking project is only just getting started.

This project, which involves coarse gangue rejection before primary flotation for safer tailings storage facilities, is expected to see a construction start in the June quarter, followed by a campaign commencement and conclusion in the September quarter and December quarters, respectively.

On another of Anglo Platinum’s big technology breakthrough projects – coarse particle rejection for post primary milling rejection of coarse gangue before primary flotation – the company plans to start a campaign in the December quarter of this year and conclude said campaign by the end of the March quarter of 2022.

The company also has eyes on making progress underground at Mogalakwena, with a hard-rock cutting project to “increase stoping productivity and safety” set for Phase A early access works this year. This project is set to involve swarm robotics for autonomous, 24/7 self-learning underground mining, the company said.

Lastly, the company’s said the digital operational planning part of its VOXEL digital platform had gone live at Mogalakwena. VOXEL is expected to eventually connect assets, processes, and people in a new digital thread across the value chain to create a family of digital twins of the entire mining environment, the company says. Development is currently ongoing.

Looking back to 2020 performance at the Unki mine, in Zimbabwe, Anglo reflected on some more technology initiatives related to R26 million of expenditure for a digitalisation program. This included installing underground Wi-Fi infrastructure, as well as a fleet data management system to track analytics on primary production equipment. The company says these digital developments will enhance real-time data analysis, improve short-interval control and overall equipment effectiveness.

To step up mechanisation of its PGM operations at Amandelbult, Anglo American Platinum is also investing in innovation.

This includes in-stope safety technologies such as split panel layouts to allow buffer times between cycles, creating safer continuous operation and reduced employee exposure; improved roof support technology and new drilling technologies; a shift to emulsion blasting from throw blasting; and safety enhancements through fall of ground indicators, 2 t safety nets, LED lights, and winch proximity detection.

Meanwhile, at the company’s Mototolo/Der Brochen operations, it is working on developing the first lined tailings storage facility at Mareesburg in South Africa to ensure zero contamination of ground water. The three-phase approach adopted for construction of this facility will be completed this year.

CRC ORE simplifies complexity for value

“There are a lot more variables to bulk ore sorting than just the technology,” Jon Rutter says.

The Principal Geologist of the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), Rutter knows his stuff. He has worked underground in both narrow-vein and mass-mining operations, as well as at large scale open-pit mines; in the base and precious metal arena.

During a presentation at International Mining Events’ IPCC Virtual event in early-February, he shared a slice of this knowledge while reviewing a recent installation project CRC ORE had been involved in at a platinum group element (PGE) operation.

“The intrinsic value of bulk ore sorting comes from the delivered heterogeneity,” Rutter said. “We have got to be able to sense and divert a higher-value pod of material versus an adjacent pod of lower-grade material on a conveyor.

“You essentially want to put more material into the mill that adds value – and not what destroys value.”

Looking at the wider bulk sorting opportunity in mining, Rutter explained the sensor diversion units (SDU) in bulk ore sorting were smaller than what the mine itself can typically offer in the form of a selective mining unit (SMU), which may be comprised of a dig block totalling around 15,000 t.

A truck offers a 100-300 t opportunity, while a shovel typically comes with a 50-100 t opportunity.

Even with a modest conveyor running at a 2,000 t/h rate, an on-board sensor (eg PGNAA or PFTNA) running at a 30 second integration time (the time to analyse one grade) would provide an SDU of 16.7 t. A sensor with lower integration time (eg XRF at 10 seconds) comes in at 5.6 t.

The ability to provide analysis down to this level has enticed several major companies into testing bulk ore sorting solutions.

Anglo American has trialled bulk ore sorting solutions at copper and platinum group metal mines, while BHP recently engaged CRC ORE to examine deployment of cutting-edge preconcentration techniques under its Grade Engineering® platform at the Olympic Dam mine, in South Australia.

The SDU with bulk sorting may be that much smaller than the SMU of a typical mine plan, but lab-level precision is not required for these solutions to work, according to Rutter.

“What I need is the ability to measure the metal content adequately,” he said. “When I say adequate, this incorporates the entire error bar of the system. That system includes the inherent geology, the mineralisation style and heterogeneity. We also need to consider the precision, accuracy and integration time – which is the technology constraint; but we also need to include the weightometers, the flop gates, the diversion gates, as well as that entire mining and materials handling process right from the start – from blasting, loading, hauling and dumping to the plant.

“But for bulk ore sorting what I end up requiring from this combined data is usually a binary decision: am I above or below a certain threshold?”

He expands on the bulk ore sorting (BOS) assessment process: “The other way of looking at this is simply considering it as planned ore loss and dilution. If we go back into that dig block, in that 15,000 t of material, I’ve already incorporated planned ore loss and dilution decisions or parameters into that SMU decision. So, if we look at bulk ore sorting, I am just talking about those different attributes – the error bars of a BOS system – as the inputs or parameters for BOS planned ore loss and dilution – it’s now just at a smaller and more precise opportunity.”

The company took a two-phase approach to the BOS opportunity at the PGE operation in question.

The first phase involved carrying out heterogeneity analysis of the orebody; correlation analysis of PGEs to base metals; selection of sensor technologies (XRF and PGNAA were selected in this case), design, layout and equipment selection for the bulk ore sorting plant; natural deportment analysis of the orebody; development of a preliminary business case; the ore type selection and sampling strategy; and project planning and management.

CRC ORE and the company in question settled on a solution where a Caterpillar 992 wheel loader dropped material off to a system using a combination of grizzly, feeder, sizer, conveyors, diverter, stackers and associated equipment from MMD, used in conjunction with an ore sensing system equipped with both PGNAA and XRF sensors to continuously measure the elemental composition. The PGNAA sensor provided a “penetrative” analysis calculation whereas XRF provided a “surface” sensing calculation, Rutter explained.

An incline conveyor ahead of the diverter gate and the accept/reject stream provided the 30 second integration time the PGNAA analyser required.

Phase two of the project involved online and offline (pre-install) work; sensor calibration; proving the technology; and proving the technology can drive physical separation.

Rutter said the completion of static calibration of the sensors saw the PGNAA sensor 20-30% calibrated, and the XRF sensor 70-80% calibrated.

This outcome harked back to Rutter’s assertion that “bulk ore sorting implementation is not a plug and play opportunity”.

A dynamic calibration in online mode completed under normal conditions was required to get the PGNAA sensor up to speed. This process, meanwhile, solidified the operation of the XRF sensor.

While the two sensors were calibrated in different ways, Rutter showed data that confirmed both were in unison when it came to reading the ore/waste that came through the conveyor (see right-hand graph below).

“The two sensors are independent of each other and fundamentally very different, but they can work well together, or separately,” he said.

CRC ORE was able to prove the technology by running the same sample through the circuit a number of times, as Rutter explained: “We fed 15-20 t of run of mine material into the hopper and repeated the process 15 times, putting the same 15-20 t sample through the system. We could then start to determine the precision and accuracy of the sensors and the system.”

For further verification, the sample was crushed, sub sampled and assayed.

“We wanted a binary response to ore and waste to build confidence,” Rutter added.

Phase three involved the ramp up to production scale, going from, say, 500 t/h to 1,000 t/h; carrying out validation by campaign; and finally integrating with the operation.

There were several lessons all mining companies – and bulk sorting vendors – should keep in mind from such a project, Rutter said.

Operations need to assess the impact of mixing across the entire materials and mining handling process as soon as possible, for one.

“The earlier we can put this data into the system, the better,” Rutter said. “Without a heterogeneity signature, we cannot implement bulk ore sorting.”

He also stressed the importance of timely feedback. Sensor calibration, a secondary crushing/sampling plant and assaying were all required to build confidence in the solution.

Rutter added: “The proper calibration of sensors does require a considerable and ongoing effort…but that is no different from any other process plant or equipment.”

Operators also need to be wary of where they set these solutions up in mines, recognising this heterogeneity dynamic.

“Bulk ore sorting is quite unlikely to be universally suited to the entire deposit,” Rutter said. “The analogue for this is a flotation plant; there are ore types in the mine where you achieve better performance in the flotation plant and others where you get worse performance.”