Tag Archives: ore sorting

NextOre’s magnetic resonance tech up and running at First Quantum’s Kansanshi

Australia-based NextOre is onto another ore sorting assignment with its magnetic resonance (MR) sensing technology, this time in Zambia at First Quantum Minerals’ Kansanshi copper mine.

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

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

Having initially successfully tested its magnetic resonance analysers (MRAs) at Newcrest’s Cadia East mine in New South Wales, Australia, the company has gone onto test and trial the innovation across the Americas and Asia.

More recently, it set up camp in Africa at First Quantum Minerals’ Kansanshi copper mine where it is hoping to show off the benefits of the technology in a trial.

The MRA in question was installed in January on the sulphide circuit’s 2,800 t/h primary crushed conveyor at Kansanshi, with the installation carried out with remote assistance due to COVID-19 restrictions on site.

Anthony Mukutuma, General Manager at First Quantum’s Kansanshi Mine in the Northwestern Province of Zambia, said the operation was exploring the use of MRAs for online ore grade analysis and subsequent possible sorting to mitigate the impacts of mining a complex vein-type orebody with highly variating grades.

“The installation on the 2,800 t/h conveyor is a trial to test the efficacy of the technology and consider engineering options for physical sorting of ore prior to milling,” he told IM.

Chris Beal, NextOre CEO, echoed Mukutuma’s words on grade variation, saying daily average grades at Kansanshi were on par with what the company might see in a bulk underground mine, but when NextOre looked at each individual measurement – with each four seconds representing about 2.5 t – it was seeing some “higher grades worthy of further investigation”.

“The local geology gives it excellent characteristics for the application of very fast measurements for bulk ore sorting,” he told IM.

Mukutuma said the initial aim of the trial – to validate the accuracy and precision of the MRA scanner – was progressing to plan.

“The next phase of the project is to determine options for the MRA scanner to add value to the overall front end of processing,” he said.

Beal was keen to point out that the MRA scanner setup at Kansanshi was not that much different to the others NextOre had operating – with the analyser still measuring copper in the chalcopyrite mineral phase – but the remote installation process was very different.

“Despite being carried out remotely, this installation went smoother than even some where we had a significant on-site presence,” he said. “A great deal of that smoothness can be attributed to the high competency of the Kansanshi team. Of course, our own team, including the sensing and sorting team at CSIRO, put in a huge effort to quickly pivot from the standard installation process, and also deserve a great deal of credit.”

Beal said the Kansanshi team were supplied with all the conventional technical details one would expect – mechanical drawings, assembly drawings, comprehensive commissioning instructions and animations showing assembly.

To complement that, the NextOre team made use of both the in-built remote diagnostic systems standard in each MRA and several remote scientific instruments, plus a Trimble XR10 HoloLens “mixed-reality solution” that, according to Trimble, helps workers visualise 3D data on project sites.

“The NextOre and CSIRO teams were on-line on video calls with the Kansanshi teams each day supervising the installation, monitoring the outputs of the analyser and providing supervision in real time,” Beal said. He said the Kansanshi team had the unit installed comfortably within the planned 12-hour shutdown window.

By the second week of February the analyser had more than 90% availability, Beal said in early April.

He concluded on the Kansanshi installation: “There is no question that we will use the remote systems developed during this project in each project going ahead, but, when it is at all possible, we will always have NextOre representatives on site during the installation process. This installation went very smoothly but we cannot always count on that being the case. And there are other benefits to having someone on site that you just cannot get without being there.

“That said, in the future, we expect that a relatively higher proportion of support and supervision can be done through these remote systems. More than anything, this will allow us to more quickly respond to events on site and to keep the equipment working reliably.”

TOMRA completes the diamond recovery loop with new XRT solution

TOMRA Sorting Mining says it is breaking new ground with a “unique” X-ray Transmission (XRT) Final Recovery solution that guarantees 99% diamond recovery.

With the new introduction, TOMRA is the first company in the industry able to supply a full diamond recovery solution using XRT technology from 2-100 mm, coupled with all the benefits of cloud computing for monitoring and managing the entire process, it said.

The new TOMRA COM XRT 300/FR final recovery sorter delivers concentration factors of up to one million with limited stages and is the only solution on the market that guarantees more than 99% diamond recovery, according to the company.

“The new sorter stands out for the high sorting efficiencies, the high diamond-by-weight concentrate, and the benefits deriving from its focus on a single consistent detection principal, diamonds,” the company said. “With this new introduction, TOMRA offers a complete partnered diamond recovery ecosystem with a flowsheet covering the entire process – from concentration to final recovery and sort house – and includes custom development with the end-user all the way to installation, then continued management of the asset and support with specialised services and training.”

The TOMRA COM XRT 300/FR is the latest step in TOMRA’s long-term diamond sector strategy, Geoffrey Madderson, Diamond Segment Manager for TOMRA Sorting Mining.

“We always had this clear objective, but the technology just didn’t exist,” he said. “We knew that to achieve our goal, we would need extremely advanced sensor technology. We have been working in-house on the development the new ultra-high resolution sensor more than five years, and now we are able to close the loop: the COM XRT 300/FR is the last piece within our recovery process, covering the final recovery and sort house applications to produce an ultra-high diamond-by-weight concentrate.”

TOMRA says its holistic approach and unique offering has earned a strong market trust in its XRT technology. As a result, the first three TOMRA COM XRT 300/FR sorters produced have already been sold to customers, all of whom purchased the machines on the back of their experience of previous TOMRA sorters.

The makeup of the TOMRA COM XRT 300/FR sorters sees input material evenly fed via a vibration feeder onto a conveyor belt. An electric X-ray tube creates a broad-band radiation, which penetrates the material and provides spectral absorption information. This is measured with an X-ray camera using DUOLINE® sensor technology, which focuses on a single, constant property of the material, density, it explained.

The advanced ultra-high resolution sensor information is processed and analysed by our TOMRA’s new Image Processing Pipeline to provide a detailed “density image” of the material, allowing it to be separated into high- and low-density fractions. If diamonds are detected, it commands the control unit to open the appropriate valves of the ejection module at the end of the conveyor belt. The detected diamonds are separated from the material flow by jets of compressed air. The sorted material is divided into two fractions in the separation chamber.

The tight tolerances and accurate alignment of the new ultra-high resolution sensor results in a high-quality picture that ensures a clear discrimination between diamonds and low-density materials down to 2 mm, according to TOMRA. The sorter features high-speed valves with a fine nozzle pitch, which significantly reduces non-diamond material in the concentrate. The result is ultra-high diamond-by-weight concentrate with a guaranteed recovery of more than 99%, the company claims.

It is possible to replace multiple sorting stages with a single TOMRA COM XRT 300/FR sorter all the way down to hand sorting, according to the company. In the final recovery application, the sorter targets the highest tonnage through the sorter that can be achieved with the highest recovery efficiency, which ranges from five tonnes to one tonne. As a result, the operation benefits from a smaller footprint and achieves much better grade.

It is also possible to replace hand sorting with a TOMRA COM XRT 300/FR. In a sort house application, it targets the highest diamond-by-weight concentrate possible, with about half the tonnage than final recovery, bringing multiple benefits. It removes the traditional bottlenecks around hand sorting efficiencies and eliminates the human error factor, the company says. In addition, it provides a high level of security by protecting the product from human intervention.

TOMRA’s partnered diamond recovery ecosystem includes consultation services during the development of the system and throughout the lifecycle of the equipment, support running the sorters, and help with specialised services and training. The company has also leveraged digital technologies to provide effective support, through its Virtual Demonstration and Test Solution and features such as the TOMRA Visual Assist Augmented Reality tool for remote assistance.

“With TOMRA, the customer’s entire recovery system falls into one ecosystem,” explains Madderson. “This allows for better compatibility and interconnectivity between the different applications of the recovery process. It gives our customers the full benefit of using cloud computing through our TOMRA Insight platform, which turns our sorters into connected machines. This enables customers to monitor and manage their recovery process in one easy-to-access place for both on-site and off-site management teams.”

TOMRA has set up a showroom dedicated to demonstrations of the TOMRA COM XRT 300/FR sorter at its Test Center in Wedel, Germany. Later in the year, TOMRA will also offer virtual demonstrations for those unable to travel to the Test Center.

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.

Northern Minerals rare earth pilot plant keeps up thyssenkrupp REC deliveries

Northern Minerals’ Browns Range rare earth pilot plant in Western Australia has continued to churn out more product, with the company set to soon make a shipment of more than 40,000 kg to offtake partner thyssenkrupp Materials Trading GmbH.

The Browns Range pilot plant has now surpassed a new production milestone of 210,000 kg of rare earth carbonate (REC), Northern Minerals said.

A shipment of 40,406 kg of REC that contains 1,835 kg of dysprosium oxide and 233 kg of terbium oxide is ready at Browns Range for delivery to thyssenkrupp, bringing total production of REC from the pilot plant to 211,109 kg.

The REC produced to date contains a total 103,731 kg of rare earth oxide, which, in turn, contains 9,751 kg of dysprosium oxide and 1,245 kg of terbium oxide: critical elements in the permanent magnet motors used in E-mobility powertrain applications.

Northern Minerals CEO, Mark Tory, said: “Despite the operational and supply chain challenges in the past 12 months, the global trend toward electrification of transport continues to accelerate as a result of regulatory changes and bold decisions by car manufacturers in transition to fully-electric fleets.

“Browns Range is still the most strategically placed heavy rare earths operation in the western world, and we continue to apply our significant R&D learnings to successfully produce batches of REC for our European offtake partner thyssenkrupp from our pilot plant in the Kimberley region of Western Australia.”

Northern Minerals started producing rare earth carbonate through the Browns Range pilot plant in October 2018 as part of a three-year pilot assessment of economic and temporary technical feasibility of a larger-scale development at Browns Range.

The company expects to commission a Steinert sensor-based ore sorter at Browns Range in the June quarter as part of its latest R&D work at the pilot plant.

TOMRA boosts sensor-based ore sorting process with key updates

TOMRA Sorting Mining has introduced the TOMRA ACT user interface together with a new image processing pipeline and additional process data for TOMRA Insight, all of which will, the company says, enable improvements in the overall sorting process for greater productivity and profitability.

The new TOMRA ACT graphical user interface (UI) brings a fundamental change in the way customers interact with their machines, making it easy to control the work flow in their sorting process with simple, intuitive touch gestures and actions on the screen, according to the company.

The UI provides sorting information and real-time process data at a glance through easy-to-understand graphics. With this clear information, the operator can better monitor the sorting process and make fast adjustments at any time, the company claims. The quick feedback on machine performance and throughput enables them to optimise the process, maximising productivity and efficiency.

Ines Hartwig, TOMRA Product Manager

Ines Hartwig, TOMRA Product Manager, explained: “Throughout the development process of TOMRA ACT, we conducted many in-depth discussions with our customers to ensure we provided them with an interface that would improve the performance of their sorters, benefitting their business. We have been testing it with customers and the feedback has been very positive; in particular about the ease of use, even remotely, which facilitates controlling the process and adjusting settings.

“With the new interface, customers interact with their sorters in a much more intuitive way and they have better guidance on how to improve the overall handling of the sorters. As a result, they will be able to improve the productivity of their sorting plant and the profitability of their mining operation.”

TOMRA is introducing the new UI on all its current X-ray Transmission (XRT) sorters and is planning to extend it to other machines in its offering at a later stage. Upgrade packages to retrofit previous models of its XRT sorters will also become available.

The new Image Processing Pipeline, meanwhile, analyses the data sent by the sorter’s sensors and cameras. This solution provides TOMRA with even more flexibility to adjust and customise the image calculations according to the application and the customer’s specific requirements to achieve the best possible sorting results.

The enhanced image processing solution also collects detailed process data, such as information on particle size distribution of the feed, belt occupancy for insights on feed tonnages, or data relating to the health of the sorter. All these statistics are fed to TOMRA Insight, the cloud-based data platform, adding to the process information it has already received. TOMRA said: “This enables customers to improve the overall sorting process further, taking fast action when changes occur in upstream equipment or in the material’s composition. They are able to better monitor and control their processes, the feed material and the sorted fractions, improving their profitability.”

The new enhanced Image Processing Pipeline, and additional data fed to TOMRA Insight, have already been introduced on TOMRA XRT sorters and will in the future be extended to other products.

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

MineSense to expand XRF ore sorting presence at Copper Mountain mine

MineSense Technologies says the use of its ore characterisation and sorting technology is seeing improvements in both the ore from waste recovery and ore dilution at Copper Mountain Mining Corp’s namesake mine in British Columbia, Canada.

Having deployed the company’s ShovelSense solution on two shovels and a wheel loader in 2020, Copper Mountain now has plans to install ShovelSense on the two remaining shovels in 2021, along with the first trial installation of BeltSense to explore additional innovation concepts, Don Strickland, Chief Operating Officer at Copper Mountain Mining Corp, said.

Jeff More, President and CEO of MineSense Technologies, said: “Copper Mountain has been a fantastic partner to work with, initially to support us in our scale-up on hydraulic shovels, and then with rapid commercial deployment once the design was stabilised.

“We are thrilled that they installed three of our ShovelSense Systems in the space of five months in 2020 and will complete installation of their entire shovel fleet in 2021.”

The MineSense hardware and software went through a two-year evaluation process at Copper Mountain prior to the solution going commercial, Copper Mountain stated in a recent technical report.

The ShovelSense system improves orebody visibility bucket by bucket in real time during the loading process, according to the company. Trucks are then automatically diverted to the correct location, increasing value and revenue realised during the mining process. The technology also creates reductions of CO2 emissions per tonne of ore produced, consumption of processing chemicals and reagents, energy and water, while maximising metal recovery.

BeltSense, meanwhile, is used on conveyance at different points of the mine operation. It can be used sequentially and in conjunction with ShovelSense to maximise the ore concentrating impact, taking a first cut at the haul point and second further downstream, MineSense says.

Both systems leverage X-ray Fluorescence sensors to carry out the sorting process.

NexGen marries ESG and financials in Arrow uranium project feasibility study

NexGen Energy CEO, Leigh Curyer, says the company’s Rook I uranium project has earnt its place as one of the “leading global resource projects with an elite ESG profile” after the publication of feasibility study results on the project’s Arrow deposit in the Athabasca Basin of Saskatchewan, Canada.

The study was completed jointly by consultants including Stantec, Wood and Roscoe Postle Associates (now part of SLR Consulting), with other technical inputs completed by sub-consultants.

Financial highlights from this study included an initial capital bill of C$1.3 billion ($1.03 billion) repaid with a post-tax net present value (8% discount) of C$3.47 billion based on a $50/Ib uranium price. From years 1-5 average annual production was due to come in at 28.8Mlb of uranium oxide, with average production over the life of mine of 10.7 years of 21.7 MIb/y.
The company laid out plans for a 1,300 t/d mill processing an average feed grade of 2.37% U3O8.

Listed within the “top five feasibility study outcomes” was enhanced environmental performance, with NexGen saying an optimised facilities layout had reduced the project footprint by around 20% and lowered on-site personnel transportation and ore haulage.

Optimised shaft sizing, water usage through advanced water recycling, and plant engineering reflected elite environmental standards, it added.

“With respect to the proposed shaft, mine workings and underground tailings management facility (UGTMF) locations, geotechnical and hydrogeological testing validated highly competent rock with no significant alteration, no major structures, and low hydraulic conductivity,” the company said.

The mine plan at Arrow was based on conventional long-hole stoping using the 239.6 MIb of declared reserves, the company said.

“Geotechnical studies during the feasibility study re-emphasised the conventional long-hole stoping mining method, including the use of longitudinal and transverse stopes, 30 m level spacing, and the nominal stope strike length of 12 m to 24 m,” it said. “This represents an excellent stope stability range for underground mining in the highly competent conditions.”

Given the competency and conditions of the underground environment, all waste streams from the process plant are planned to be stored underground in the UGTMF, while process water streams will be treated on surface in the optimised effluent treatment plant, NexGen said.

The underground workings will be accessed by two shafts, with the production shaft supporting personnel movements, materials, ore, waste and fresh air. The production shaft was increased to 8 m in diameter (from 6.5 m in diameter in the prefeasibility study (PFS)) to optimise radiation and ventilation management, ensuring the mine is elite from a safety perspective, the company said.

“Additionally, the production shaft will have divided compartments, ensuring that fresh air and personnel entering the mine, remain isolated from ore being skipped to surface,” it added.

The exhaust shaft was ultimately decreased to 5.5 m in diameter (from 6.5 m in diameter in the PFS) and will be used for exhaust air and emergency secondary egress, NexGen said.

Like some other projects in the region, shaft freezing will be required to a point to secure the underground project, NexGen confirmed.

In terms of processing, NexGen said extensive test work and engineering had determined that proven technology in a conventional uranium processing flowsheet is most effective to produce uranium oxide from the Arrow deposit.

The main components of the processing plant are ore sorting; grinding; leaching; liquid-solid separation via counter current decantation and clarification; solvent extraction; gypsum precipitation and washing; yellowcake precipitation and washing; yellowcake drying; calcining and packaging; and tailings preparation and paste tailings plant.

Metallurgical testing resulted in supporting and refining process design parameters, with the process recovery of 97.6% confirming the predictable nature of the processing flow sheet, it said.

“The feasibility study also confirmed that all processed waste streams can be stored in the UGTMF and no surface tailings facility is required,” NexGen said. “The UGTMF is a reflection of NexGen’s industry-leading environmental design approach, contributing to the significant reduction of the project’s surface footprint, and representing an opportunity to implement best practice of progressive closure of tailings facilities during the operational phase of the mine.”

A feasibility study drill program validated the geotechnical conditions and favourable conditions for the UGTMF, with the study also optimising the geotechnical design, size and sequencing of the UGTMF included in the mine plan.

The study test work demonstrated paste fill strength met or exceeded all requirements set in the feasibility study design for a potential paste-backfill to be used for underground stope stability.

In terms of the timeline to production, NexGen said it planned to submit its Environmental Impact Statement in the second half of this year, along with relevant licences.

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.

Hochschild’s Inmaculada set for ore sorting pilot plant

Hochschild says it has approved a $7 million budget to construct an ore sorting pilot plant at its Inmaculada gold mine in Peru in 2021.

The investment follows previous test work carried out with both TOMRA and Steinert. This saw the company conduct initial bulk testing in Germany with both companies and a 20-t pilot scale test with Steinert in Brazil.

The company also enlisted the help of Ausenco to carry out a prefeasibility study on applying ore sorting at Inmaculada.

In the company’s 2019 preliminary results presentation back in February, Ramón Barúa, Hochschild Mining Chief Financial Officer, said ore sorting could prove particularly useful at the Millet and Divina veins at Inmaculada.

He said, in addition to consulting with TOMRA, Steinert and Ausenco, the company had been working in-house to improve the sensors and the algorithm that separates the ore from the waste in these sorters, with the technology showing a clean separation between the quartz-based mineralisation and the andesite holding the rock at Inmaculada.

In its latest financial year results released today, Hochschild said of the ore sorting investment: “We believe this project may eventually deliver significant improvements in recoveries at the mine and potentially help to optimise other key projects in Hochschild’s portfolio.”

For 2020, the company recorded overall production of 289,293 oz of gold-equivalent at an all-in sustaining cost of $1,098/oz of gold equivalent. Inmaculada remained the cornerstone of the company, producing 176,086 oz of gold-equivalent.