Tag Archives: Crushing

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.

eHPCC: the future of grinding in mining?

A lot has been made of the potential of high pressure grinding rolls (HPGRs) to facilitate the dry milling process many in the industry believe will help miners achieve their sustainability goals over the next few decades, but there is another novel technology ready to go that could, according to the inventor and an independent consultant, provide an even more effective alternative.

Eccentric High Pressure Centrifugal Comminution (eHPCC™) technology was conceived in 2013 and, according to inventor Linden Roper, has the potential to eliminate the inefficiencies and complexity of conventional crushing and/or tumbling mill circuits.

It complements any upstream feed source, Roper says, whether it be run of mine (ROM), primary crushed rock, or other conventional comminution streams such as tumbling mill oversize. It may also benefit downstream process requirements through selective mineral liberation, which is feasible as the ore is comminuted upon itself (autogenously) in the high pressure zone via synchronous rotating components. Significant product stream enrichment/depletion has been observed and reported, too.

As IM goes to press on its annual comminution and crushing feature for the April 2021 issue – and Dr Mike Daniel, an independent consultant engaged by Roper to review and critique the technology’s development, prepares a paper for MEI Conferences’ Comminution ’21 event – now was the right time to find out more.

IM: Considering the Comminution ’21 abstract draws parallels with HPGRs, can you clarify the similarities and differences between eHPCC and HPGR technology?

MD & LR: These are the similarities:

  • Both offer confined-bed high-pressure compression comminution, which results in micro fractures at grain boundaries;
  • Both have evidence of preferential liberation and separation of mineral grains from gangue grains at grain boundaries; and
  • Both have an autogenous protective layer formed on the compression roll surfaces between sintered tungsten carbide studs.

These are the differences:

  • eHPCC facilitates multiple cycles of comminution, fluidisation and classification within its grinding chamber, retaining oversize particles until the target product size is attained. The HPGR is a single pass technology dependent on separate materials handling and classification/screening equipment to recycle oversize particles for further comminution (in the event subsequent stages of comminution are not used);
  • Micro factures around grain boundaries and compacted flake product that are created within HPGRs need to be de-agglomerated with downstream processing either within materials handling or wet screening. In some instances, compacted flake may be processed in a downstream ball mill, whereas, in eHPCC, preferential mineral liberation is perfected by subsequent continuous cycles within the grinding chamber until mineral liberation is achieved within a bi-modal target size (minerals and gangue). The bi-modal effect differs from ore type to ore type and the natural size of the minerals of interest;
  • The preferential liberation of mineral grains from gangue grains generally occurs at significantly different grain sizes, respectively, due to the inherent difference in progeny hardness. eHPCC retains the larger, harder grains, hence ensuring thorough stripping/cleaning of other grain surfaces by shear and attrition forces;
  • eHPCC tolerates rounded tramp metal within its grinding chamber, however does not tolerate high quantities of sharp, fragmented tramp metal that create a non-compressible, non-free-flowing bridge between roll surfaces, which risks the damage of liner surfaces;
  • The coarse fraction ‘edge effect’ common in HPGR geometry is not an issue with eHPCC. In fact, the top zone of the eHPCC grinding chamber is presumed to be an additional portion of the primary classification zone within the grinding chamber. The oversize particles from the internal classification process are retained for subsequent comminution;
  • The maximum size of feed particle (f100) entering the eHPCC is not limited to roll geometry as is the case with HPGRs (typically 50-70 mm). eHPCC f100 is limited to feed spout diameter (for free flow) and dependent of machine size ie eHPCC-2, -5, -8 and -13 are anticipated to have f100 60 mm, 150 mm, 240 mm and 390 mm, respectively. The gap between rolling surfaces is greater than the respective f100; and
  • eHPCC technology shows scientifically significant product stream enrichment.

IM: What operating and capital cost benefits do you envisage when compared with typical HPGR installations?

MD & LR: Both operating and capital cost benefits of the eHPCC relative to HPGR technology are due to the eHPCC not requiring the pre-crushing and downstream classification equipment required by HPGRs.

The eHPCC operating cost benefits are associated with eliminating maintenance consumables, downtime, reliability issues and energy consumption associated with the equivalent HPGR downstream equipment listed above.

The eHPCC capital cost benefits are associated with eliminating the real estate (footprint) and all engineering procurement and construction management costs associated with the equivalent HPGR upstream/downstream equipment listed above. eHPCC flowsheets are likely to be installed as multiple ‘one-stop’ units that maintain high circuit availability due to ongoing cyclic preventative maintenance.

IM: Where has the design for the eHPCC technology come from?

LR: It was invented in early 2013 by me. I then pioneered proof-of-concept, prototyping, design and development, culminating in operational trials in a Kazakhstan gold mine in 2020. A commercial-grade detailed design-for-manufacture has since been undertaken by a senior team of heavy industry mechanical machine designers and engineers.

IM: In your conference abstract, I note that the eHPCC technology has been tested at both laboratory and semi-industrial scale with working prototypes. Can you clarify what throughputs and material characteristics you are talking about here?

LR: The first iteration of the technology, eHPCC-1, was tested at the laboratory scale from 2013-2015. This proof-of-concept machine successfully received and processed magnetite concentrate, copper-nickel sulphide ore, alkaline granite, marble and a wolfram clay ore dried in ambient conditions. The typical throughput was between 200-400 kg/h depending on the feed size, particle-size-reduction-ratios (dependent of grain size) and target product size. The feed size was limited to a maximum of 25 mm to ensure free flow of feed spout.

Alkaline granite: eHPCC-2 coarse product (left) and fine product (right)

MD & LR: From 2016-2020, we moved onto the semi-industrial scale testing with the eHPCC-2 (two times scaled up from eHPCC-1). This was designed for research and development (R&D) and tested on magnetite concentrate, alkaline granite, and hard underground quartz/gold ore. The throughput capabilities depended on the geo-metallurgical and geo-mechanical properties of feed material, such as particle size, strength, progeny (grain) size and particle size-reduction-ratios (subject to confined bed high pressure compression). Larger-scale machines are yet to be tested against traditional ‘Bond Theory’ norms.

The eHPCC, irrespective of the outcomes, should be evaluated on its ability to effectively liberate minerals of interest in a way that no other comminution device can do. The maximum feed size, f100, at the gold mine trials was limited to 50 mm to ensure free flow through the feed spout. R&D culminated in pilot-scale operational trials at the Akbakai gold mine (Kazakhstan), owned by JSC AK Altynalmas, in 2020, where SAG mill rejects of hard underground quartz/gold ore were processed. The mutual intent and purpose of the tests was to observe and define wear characteristics of the eHPCC grinding chamber liners (roll surfaces). These operational trials involved 80% of the feed size being less than 17 mm and a variety of targeted product sizes whereby 80% was less than 1 mm, 2 mm, 2.85 mm and 4.8 mm. The throughput ranged from 1-5 t/h based on the size.

IM: What throughputs and material characteristics will be set for the full-scale solution?

LR: There will be a select number of standard eHPCC sizes. Relative to the original eHPCC-1, the following scale-up factors are envisaged: -2, -3, -5, -8, and -13. These are geometrical linear scale-up factors; the actual volumetric capacity is a cube of this factor, with adjustments for centripetal acceleration. Currently -13 times seems to be the maximum feasible size of the present detailed design philosophy, but there are no foreseeable limitations in terms of feed materials with exception to moist clay. Clay was successfully processed after drying the feed in ambient temperatures during testing. Further testing of moist clays blended with other materials that can absorb the moisture as they comminute would be desirable.

IM: Other HPGRs can also be equipped with air classification technology to create dry comminution circuits. What is the difference between the type of attrition and air classification option you are offering with the eHPCC?

MD & LR: Two modes of comminution occur in the particle bed of eHPCC repetitively and simultaneously. First, confined bed pressure compression breakage occurs at a macro level that promotes shear/compression forces greater than the mineral grain boundaries. Second, Mohr-Coulomb Failure Criteria (shear/attrition) that completes the separation of micro fractures on subsequent cycles takes place.

The nip angle between the rotating components of eHPCC technology never exceed 5°. During the decompression and fluidisation portion of the cycle, the softer species – which are now much smaller – are swept out of the fluidised particle bed against centrifugal and gravitational forces by process air. The larger species, influenced by centripetal acceleration, concentrate at the outer diametric and lower limits of the conical rotating grinding chamber, continuing to work on each other during each subsequent compression phase.

HPGRs are limited to one single-pass comminution event, requiring downstream external classification and subsequent recycling/reprocessing of their oversize and/or flake product.

IM: How will it improve the mineral liberation and separation efficiency compared with other grinding solutions that combine both?

MD: eHPCC technology could compete with the Vertical Roller Mill and Horomill, however, eHPCC is likely to be more compact with high intensity breakage events contained within the all-inclusive system of breakage, classification and removal of products.

IM: When was it most recently tested and over what timeframe?

LR: The eHPCC-2 pilot plant was mobilised, setup and commissioned in March 2020, but its operation was suspended until June 2020 due to COVID-19 quarantine restrictions and a need to cater to abnormal amounts of ball fragments in the feed, the latter of which pushed the treatment of tramp metal to the extreme. The machine operated for the months of June and July using liners constructed of plasma transferred arc welded (PTAW) tungsten carbide (TC) overlay. During this period, a total of 795 t was processed at various targeted product sizes, with, overall, an average throughput of 3 t/h (nominally 265 operating hours) processed.

Side view of pilot system including feed hopper and weigh-scale feeder (right), feed conveyor (middle foreground), control and auxiliaries (middle background), eHPCC-2 (left foreground), dust bag-house (left background) and product conveyor and stockpile (not shown left background)
Front-end loader filling feed hopper with SAG mill rejects f80 18 mm

The PTAW-TC overlay was deemed unsustainable as it was consumed rapidly and demanded continuous rebuilding due to the high pressure intensive abrasive wear on the convex cone. The pilot plant operation was mostly suspended during the month of August while an alternative tungsten carbide studded liner, analogous to HPGR studded rolls, was manufactured for simulating a trial of this studded liner philosophy. The studded liner philosophy was operated in the eHPCC-2 in Kazakhstan for sufficiently long enough to ascertain the creation of the autogenous protective wear layer of rock between the studs, with the simulation trial deemed a success. The design philosophy shall be adapted on the commercial-grade eHPCC.

eHPCC-2 TungStud™ as-new (left) high-pressure-air-cleaned (middle) and brushed (right)

The pilot plant was demobilised from the Akbakai site laydown area on September 10, 2020, to release the area for construction of a non-related plant expansion. The operational experiences of the pilot plant at Akbakai provided valuable knowledge and experience pertaining to mechanical inertia dynamics and design for eliminating fatigue within eHPCC components.

IM: Aside from the test work on trommel oversize at the Kazakhstan gold mine, where else have you tested the technology?

LR: eHPCC has no other operational experiences so far. Investment and collaboration from the industry to progress the commercialisation of eHPCC is invited. The commercial-grade eHPCC-2.2 is designed and ready for manufacture.

IM: Is the technology more suited to projects where multiple streams can be produced (fines, coarse piles, etc)?

LR: eHPCC is configurable to meet the demands and liberality of a diverse spectrum of feed materials and the potential downstream extractive processes are complementary to eHPCC product streams. Therefore, it would be incorrect to categorise it as more suitable in any one niche; it is configurable, on a case-by-case basis, to meet the liberality of the specific progeny of the feed.

IM: What energy use benefits do you anticipate by creating a one-step comminution and classification process over the more conventional two-step process?

MD & LR: The energy saving benefits include:

  • Elimination of tumbling mill grinding media consumption;
  • Elimination of the liberal wastage of randomly directed attrition and/or impact events that indiscriminately reduce the size of any/all particles (gangue or precious mineral) with the conventional tumbling mill; and
  • Elimination of energy consumption of the materials handling systems between the various stages of comminution and classification, be it dry belt conveying, vibrating screens, classifiers, cyclone feed pumps, cyclones and their respective recirculating loads that can be upward of 300% of fresh feed.

IM: Do you anticipate more interest in this solution from certain regions? For instance, is it likely to appeal more to those locations that are suffering from water shortages (Australia, South America)?

MD & LR: We suspect the initial commercialisation growth market to be from base metals producers seeking to expand or retire existing aged/tired comminution classification capacity, followed by industry acknowledgement of the technology’s potential to shift the financial indicators of other potential undeveloped projects into more positive territory. This latter development could see the technology integrated into new projects.

In general, the technology will appeal to those companies looking for more efficient dry comminution processes. This is because it offers a pathway to rejection of gangue at larger particle sizes, early stream enrichment/depletion and minimal overgrinding that creates unnecessary silt, which, in turn, hinders or disrupts the integrity of downstream metallurgical extraction kinetics, and/or materials handling rheology, and/or tailings storage and management.

LR: There are a number of rhetorical questions the industry needs to be asking: why do we participate in the manufacture and consumption of grinding media considering the holistic end-to-end energy and mass balance of this (it’s crazy; really why?)? Why do we grind wet? What are the barriers preventing transition from philosophising over energy efficiency, sustainability etc and actually executing change? Who is up for a renaissance of bravely pioneering disruptive comminution and classification technology in the spirit of our pioneering forefathers?

The more these questions are asked, the more likely the industry will find the solutions it needs to achieve its future goals.

Dr Mike Daniel’s talk on eHPCC technology will be one of the presentations at the upcoming Comminution ’21 conference on April 19-22, 2021. For more information on the event, head to https://mei.eventsair.com/comminution-21/ International Mining is a media sponsor of the event

Metso Outotec cuts cost and size with SUPERIOR MKIII 6275UG primary gyratory crusher

Metso Outotec has launched a new extension to its primary gyratory crusher range that could find a home in open-pit and underground mines where space constraints are an issue.

The SUPERIOR™ MKIII 6275UG can be used in different types of applications and provides large capacity with significant savings in capital expenditure and operating costs, the company says.

Jim Bathie, VP Mining Crushers at Metso Outotec, said: “We are very excited about the SUPERIOR MKIII 6275UG. As a direct response to the market demand, we’ve designed a more compact primary gyratory crusher reducing capital expenditure that is applicable to both underground and above ground applications for the mining industry.

“We think that we have achieved our goal and upheld the superior standards we are known for.”

The crusher was born out of a need for a high capacity underground primary crusher that did not require a primary feeder, scalper, and the associated infrastructure therein, the company said. Minimising the need for high cost stationary grids to control topsize underground was a requisite, and the large topsize acceptance was met with the UG design, it claimed.

Additional requirements for an underground crusher were the ability to transport the components down shafts with spacial restrictions, assemble the crusher with minimal need for welding and hot works, and the ability to feed the crusher from 360° around the feed opening – “these were all met with the 6275UG MKIII”, the company said.

The 6275UG crusher’s feed opening is 15% larger than similar crushers, while also reaching up to 30% more capacity than comparable crushers, according to the company. The up to 10% reduction in station height translates into capital cost reductions of as much as 20%, Metso Outotec claims.

Some additional key design targets for this new crusher were less downtime and easy maintenance. With the MKIII UG, downtime can be reduced by up to 70% thanks to concave replacements with another Metso Outotec proprietary innovation, the Rotable Topshell.

The SUPERIOR MKIII 6275UG is designed to be part of a SmartStation, where productivity and availability are optimised with sophisticated automation in each phase of the process, the company says.

Incoming material analysis can be carried out automatically with VisioTruck™, and Metso Outotec Metrics provide analytical dashboards and condition monitoring to ensure optimal crusher performance. A consistent vault level is ensured with automatic crusher adjustments, while VisioRock™ and control system are used for wear compensation.

Fortuna keeps Lindero on track for first gold pour in early October

Fortuna Silver Mines says it has started the irrigation and leaching of ore placed on the heap leach pad at the Lindero gold project, in Salta Province, Argentina.

This is ahead of the first gold pour, expected in early October.

Jorge A Ganoza, President, CEO and Director, said: “In spite of all the restrictions and challenges brought by the COVID-19 pandemic, we are managing to successfully advance Lindero in a safe and secure manner for our personnel and neighbours.

“With the start of irrigation, we achieved one more key milestone in the pre-production phase as we prepare for what follows, the first gold pour at our third producing mine.”

Back in July, Fortuna said it had completed the primary and secondary crushing circuits at Lindero and it had started stacking ore on the heap leach pad.

The night shift operations at the primary and secondary crushing circuits began in mid-August and, at month’s end, daily throughput peaked at 17,400 t/d or 93% of design capacity of 18,750 t/d, Fortuna said.

This has seen 277,000 tonnes of ore averaging 0.87 g/t Au, containing an estimated 7,750 oz of gold, placed on the leach pad as of August 31.

Meanwhile, irrigation and leaching of ore on the leach pad commenced on September 1. The company also noted that pre-commissioning of the ADR (adsorption, desorption and regeneration) plant was 80% complete.

Sandvik cone crushers go circular with recycled wear parts

Sandvik Group is encouraging circularity in the mining industry through the recycling of steel from used cone crusher parts to make new crushing equipment.

While extractive industries such as mining are responsible for 50% of global carbon dioxide (CO2) emissions, recycling steel from mining equipment could make all the difference, according to Anders Åkesson, QM EHS Manager, Crushing & Screening at Sandvik Mining & Rock Technology (SMRT).

Circularity is becoming vital in the reduction of CO2 emissions, and can help improve the environmental position of many industries. With the mining industry contributing a large percentage of global CO2 emissions, implementing circularity could help it make vital reductions, Åkesson says.

To produce equipment, the mining industry predominantly uses manganese steel, which is renowned for its work-hardening properties and resistance to abrasion. This means the material becomes harder with the more impact it receives, creating a low friction surface suited to crushing. For this reason, manganese steel has been used in high impact applications for over 100 years, making it an ideal material for cone crushers.

Cone crushers are used to grind down rocks, which are fed into the top of the crusher and pressed between the mantle and the cone. This breaks the rock down into smaller fragments, which are then passed through lower levels of the crusher where they are broken down further.

“It’s vital that cone crushers are made from a material that provides the necessary force to grind the rocks, while withstanding the abrasive nature of the process,” Åkesson said.

Using recycled steel from used cone crusher parts to make new cone crushers, Sandvik SMRT has demonstrated and improved circularity of steel production for mining equipment, he explained. The division was nominated for Sandvik’s first sustainability award in April 2020, which recognises sustainable innovations from its employees.

Sourcing manganese steel from one of the world’s most sustainable manganese foundries, based in Sweden, was the first step SMRT took towards its sustainable innovation. A total of 91% circular steel was used to manufacture wear parts, such as the cone and mantle of a cone crusher. These wear parts are reused to produce new wear parts for the cone crushers – creating a continuous cycle, Åkesson said.

Moving away from a linear model, Sandvik increased the circularity and sustainability of its products and eliminated 79% of production emissions, according to Åkesson. “In addition, Sandvik cone crushers help SMRT’s customers to lower their environmental impact as they are buying from the circular economy – contributing to their own sustainability goals,” he said.

Åkesson concluded: “With mining contributing towards CO2 emissions in more ways than one, it’s essential that the industry uses methods that reduce emissions. Reusing and recycling steel to manufacture mining equipment has demonstrated an opportunity that helps meet the sustainability goals of both equipment suppliers and their customers. If the industry wants to become circular, taking a look at equipment a good place to start.”

MRL and Metso Outotec NextGen II crushing plant installation on track

Mineral Resources and Metso Outotec’s plans to deliver their NextGen II modular crushing plant to BHP’s Mt Whaleback mine remain on course, with the fabricated steelwork having arrived in Western Australia.

In January 2020, the joint venture awarded a fabrication contract to three separate companies in Turkey: Birikim and Mass Makina, in Ankara, and Bilim Makina, in Bursa, around 100 km south of Istanbul.

The contract was to procure, fabricate, trial assemble, surface treat, and deliver to the port about 1,400 t of fabricated steel work. This effort was led by Mineral Resources Technical Director, David De Haas, and Fabrication Manager, Michael Killeen.

Mineral Resources’ wholly-owned subsidiary, CSI Mining Services, has now received this infrastructure, with all NextGen II works to be assembled at CSI’s Kwinana workshop during a six-week period, working 24/7.

The assembly of the 12 Mt/y plant will be completed on site at BHP’s Mt Whaleback mine, replacing the existing CSI crushing plant at the iron ore operation. This contract was announced last month.

“The manufacture of NextGen II has been completed in very difficult times internationally as the coronavirus pandemic swept the world and the whole team is to be congratulated for their efforts,” Mineral Resources said.

“We look forward to the successful construction, installation and commissioning of the new plant at Mt Whaleback, and are confident this will be the first of many opportunities for this ground-breaking approach to deliver safe, reliable production for the hard-rock crushing industry.”

The company concluded: “CSI is already the world’s largest crushing contractor and NextGen II will help us maintain our position as the partners of choice for the mining industry.”

The first 12 Mt/y portable and modular NextGen crushing plant was installed in 2018 at the Pilgangoora lithium project, owned by Pilbara Minerals, in Western Australia.

TOMRA makes recovery promise to diamond miners

TOMRA is offering diamond mining customers a guaranteed diamond recovery of greater than 98% with the use of its sensor-based ore sorting technology.

The company is making this guarantee alongside a promise of 100% detection in the specified range, irrespective of luminescence profile or coating.

As the company says, maximising diamond recovery while optimising costs is the top priority for every diamond producer.

“With TOMRA’s holistic approach and cutting-edge technologies, both can be achieved to deliver outstanding results,” it said, adding that its X-ray Transmission (XRT) diamond recovery technology has helped recover some of the largest and rarest gemstones in history.

TOMRA says it approaches every project as a partnership with the customer to deliver a complete solution that meets their operational and business requirements.

This begins with a detailed analysis of the customer’s requirements and operational needs.

TOMRA – Operations Hub Johannesburg

Working collaboratively, it assists in developing a tailor-made flowsheet redesign that combines its XRT technology with its Near Infrared (NIR) and Laser solutions as needed. This collaborative approach continues throughout the project, with testing at its Test Center in Germany and, on-site, as required, through to installation and beyond.

More recently, this approach has been enhanced with the development of a remote testing option.

“The complete solution can also include the web-based TOMRA Insight platform that turns all the sorters into connected devices for monitoring and tracking the system’s performance,” the company said.

Once the system is fully operational, TOMRA offers its Service Level Agreement to ensure its solution continues to deliver the desired results.

“The tailored agreement can include on-site presence as required, seven days a week product support, application engineer visits, tiered urgency support, targeted site response, training, as well as spare and wear parts coverage to ensure maximum uptime and protect the customer’s investment,” the company said.

Advanced technologies adding value

TOMRA’s XRT technology recognises and separates material based on its specific atomic density. It uses a cutting-edge X-ray camera with DUOLINE® sensor technology to measure spectral absorption information.

TOMRA’s proprietary high-speed X-ray processing unit uses the data to produce a detailed “density image” of the material. The result is a high level of purity in sorting materials, irrespective of size, the degree of moisture or surface pollution present, TOMRA says. This makes TOMRA’s XRT high-capacity sorters effective in the recovery of free, liberated diamonds at high feed rates up to 300 t/h.

TOMRA’s NIR sorters recognise and separate kimberlite and waste rock based on their chemical composition. This technology is useful in upgrading lower grade run of mine and stockpiles, producing a kimberlite concentrate for further processing, the company says.

Marie-Claude Hallé had first-hand experience of how TOMRA’s solutions can add value to diamond mining operations when she held the role as Marketing Operations Manager for diamond exploration and producing company, Stornoway Diamonds.

“You have to really envision that TOMRA has actually changed the game in terms rough diamond recovered around the world and allowed producers to access large exceptional quality goods that perhaps in the past would be crushed to pieces,” Hallé said.

Customised solutions for kimberlite, lamproite and alluvial applications

With its customised approach, TOMRA says it can deliver on its promise of guaranteed results both in hard-rock kimberlite/lamproite and alluvial deposits – each of which presents their specific challenges.

In kimberlite, the challenge is to recover “needle in a haystack” diamonds, which requires controlled crushing of kimberlite ore to avoid damaging or breaking the diamonds, the company says.

“High waste dilution impacts the crushing energy needed and further increases diamond breakage risk,” TOMRA says. “Utilising TOMRA NIR technologies, we can remove non-diamond bearing material, not only improving the crushing profile of the ore, but also increasing the value of each tonne of ore processed. TOMRA NIR waste sorting technology can make diluted marginal kimberlite deposits economic.”

Additionally, complex, energy- and water-intensive kimberlite liberation processes, and the cost of transportation for crushing and processing, are challenges facing modern diamond miners today.

“TOMRA’s XRT and NIR technologies, which offer extremely high concentration factors, allow the production of hand sortable, ultra-high grade concentrates in as little as two stages compared to up to seven in traditional methods,” the company claims.

The challenge of economically mining low-grade alluvial deposits is due to their typically lower grade and the sporadic nature of the deposits.

The high recovery performance of TOMRA’s XRT technology enables single-stage or double-stage diamond recovery, offering a drastically lower operating cost and capital investment so that mining marginal deposits becomes economically viable, according to TOMRA.

“Another advantage of TOMRA’s XRT solution is that it can operate as a dry process, which dramatically reduces its environmental impact and operational complexity,” it says. “Besides, it opens the door to new opportunities, making it possible to mine deposits in arid areas where water access is minimal.”

TOMRA XRT machines have proved effective in alluvial operations, the company says.

One such case is that of the Lulo mine in Angola, operated by Lucapa Diamonds, where TOMRA XRT technology is used to process material between 18 and 55 mm in size and allows the recovery of diamonds of up to 1,100 ct – and where it has recovered Angola’s second-biggest diamond on record, a 227 ct stone in 2017.

Stephen Wetherall, Lucapa Diamonds Managing Director at the time of the recovery, said: “The recovery of the 227 ct diamond using the new XRT circuit justifies our investment in TOMRA’s large diamond recovery technology, which has more than paid for itself with the recovery of this one stone alone.”

Optimised flowsheet

TOMRA is in the unique position of being able to offer diamond operations a full XRT recovery flow sheet to 2 mm that delivers concentration factors up to 1 million with a much-reduced number of concentration stages, it says.

Geoffrey Madderson, Diamond Segment Manager for TOMRA Sorting Mining, explains: “TOMRA XRT technology replaces multiple stages of diamond concentration by virtue of its ability to concentrate diamonds to a hand sortable product after only a single step. This concentration factor allows for the removal of multiple recovery steps, drastically reducing both the capital investment and operational costs to recover diamonds.”

Geoffrey Madderson, Diamond Segment Manager for TOMRA Sorting Mining

TOMRA’s XRT technology can replace traditional methods such as dense media separation (DMS), wet magnetic separation and XRL final recovery with single-stage solutions for +8 mm and double-pass for -8 mm +4 mm particles, it claims.

“TOMRA’s solution eliminates up to seven concentration stages, dramatically reducing the complexity of the supporting plant and infrastructure,” the company says. “This results in significantly lower power and water consumption, which not only reduces costs, but also the environmental impact of the recovery process.”

An additional benefit of TOMRA’s solution is that it is a fully automated process, so there is no manual handling during pre-concentration and recovery, which has positive implications on security and eliminates human error, resulting in greater accuracy, the company says.

Recoveries

TOMRA’s sorters process these volumes with great efficiency, finding more diamonds than other, traditional separation methods – including coated and low- or non-luminescent diamonds, the company says.

The performance of its XRT sorters is independent of the “heavies” content in the feed, and is ideal for processing high-yielding ores unsuitable for DMS. The result is an exceptionally high recovery rate, it claims.

“TOMRA guarantees >98% recovery: that is how confident we are in our technology,” Madderson states.

With TOMRA’s sorting solutions, diamond producers can install large diamond recovery systems with a small capital investment and operate with a fraction of operating expenditures per tonne compared with traditional recovery methods such as DMS and XRL, it claims. In addition, the economic recovery of ultra low-frequency exceptional diamonds of +32 mm is now possible.

“TOMRA’s ability to deliver not only a technology that can detect such large diamonds, but also an economical process solution for the recovery of ultra-rare, exceptional diamonds is what sets it apart from its competitors,” Madderson said.

“This is the reason that, to date, TOMRA XRT has become synonymous with the recovery of extraordinary diamonds from all around the world.”

Filling the mineral processing flowsheet gaps

Crushing, grinding, flotation, solvent extraction, electro winning, tailings management…Metso Outotec covers it all.

The new mineral processing entity might be less than a week old, but many in the industry would have, no doubt, had some burning questions to ask since the planned merger was announced on July 4, 2019.

IM had a chance to put some of these questions to Stephan Kirsch, President Minerals business area, Metso Outotec, gaining an initial impression of what the combination of the two companies means for the Minerals business he heads up.

IM: What big mining industry challenge will the combined group be better placed to tackle? What equipment/solutions/expertise within the group are the most important in achieving these goals?

SK: One issue – although not technology-focused – is community engagement.

Some mining operations in the world face challenges in terms of engaging with local communities and returning benefits to them. There is a social responsibility for mining companies, as they are the operators, but also for mining industry supporters involved in such projects.

That said, the vast majority of the mining industry runs initiatives that ensure communities understand mining companies are not just there to extract the iron, copper or gold and make money from it. They give back to local stakeholders and help improve community standards.

Stephan Kirsch, President Minerals business area, Metso Outotec

From a technology perspective, an industry issue we are well equipped to tackle is tailings management. With our combined offering, we look very seriously into solutions that can involve dewatering, dry stacking, and the reprocessing of tailings.

You asked about the products involved in solving these challenges…that includes filtration technologies, bulk materials handling products for conveying and stacking, and then various ore sorting technologies for the reprocessing.

Another trend to highlight is the use of energy or, more specifically, the need to reduce power consumption. There is some work to do here.

When you go and buy a car, you tend to focus on the fuel consumption. The mining industry, however, aims for high installed power because there is a sentiment that more power in the mill means more product out of the mill, more fines and, as a result, better downstream recoveries. In a way that is true for technologies like horizontal mills, ball mills and SAG mills, but when you turn to different, newer technologies it is not always the case.

One of these technologies is HPGRs which were introduced in the minerals industry in the mid-80s. Today, HPGRs are used in high tonnage, competent, abrasive ore applications due to their lower specific power draw and other downstream benefits compared to conventional technologies.

One can add to this, conserving other natural resources such as water. Water scarcity is obviously a problem and we should look at the recycling of process water wherever possible (that is where the filtration technology comes into play again) at the same time as examining more energy-efficient flowsheets.

There is quite a bit we can do to solve some of these challenges from a mineral processing perspective, but, the problem is, the industry remains conservative and anything new takes time to be implemented sustainably.

IM: I know Metso has previously talked about creating a bulk ore sorting solution for industry. Considering this, do you as Metso Outotec expect to continue leveraging the agreement Outotec has in place with TOMRA to carry out more sensor-based ore sorting projects? Alongside this, will you continue with your own bulk sorting projects?

SK: Early removal of tailings/overburden from the processing plant feed has been the operator’s dream for probably a century! This concept of preconcentration has been a consideration for many years, but in the last 30 or so years, technologies with different sensors have been developed to help with this separation process.

It is the ability to use sensor technology to single out particles on a conveyor belt at an appropriate speed and quantity that is the industry challenge. After all, when it comes to mining, we are talking about bulk materials that must be processed, not single elements like you have in the recycling and food sectors where much of this sensor technology originated from.

You need to look at the operating economics of such plants. When I say economics, I am factoring in throughput and recovery rates: you want a high tonnage and you don’t want to waste your ore, which is already low grade compared with what was being mined, say, 30 years ago.

The answer to your question is that Metso has been looking into preconcentration technologies for some time – we have R&D projects and partners looking at it. The same is the case with Outotec. Going forward, we will analyse this and make a call on whatever is the best combination to continue with such work.

Personally, I am a big believer in segregating waste as early in the process as possible to save energy downstream. But there are technical challenges to this.

IM: Both companies have been expanding their modular offering in recent years (Metso with its flexible FIT™ stations and the smart Foresight™ stations/Outotec with its modular paste backfill plants and HIGmill): is a lot of your mining and metals R&D currently focused on reducing the footprint of your solutions?

SK: Our R&D budget – as you probably heard on the webcast last week – is quite significant when put together. As Metso Outotec committed to keep both of our budgets unchanged, the spend comes to about €100 million ($112 million). A market survey we carried out revealed that, in terms of R&D spend, we are at the top of the industry.

Then, we must spend this money wisely wherever we see it being applied most economically for the benefit of our customers and for Metso Outotec. The modular crushing stations you mention are an area of interest we started developing years ago. We see good potential for this modular offering and will continue to develop it.

As for the percentage of the budget we will dedicate to it, this will – like all R&D projects – be analysed alongside others for crushing, grinding and all separation technologies with a strong focus on product innovations, digitalisation and sustainability.

IM: As you hinted at earlier, do you see tailings management being one of the combined group’s core strengths?

SK: It is one big focus area for us, but only one.

Crushing and grinding, which I mentioned earlier, is another strong area. We are a market leader in some of the crushing technologies we offer, and high up the industry when it comes to grinding technologies. We plan to really expand on this side.

I mentioned HPGRs where we have brilliant, world-class technology, but are missing the installed base. With 20-25 years of HPGR experience, I know we have the technology to make a difference, we just need to effectively bring it to market.

The whole re-grind space is really a future area for us to pursue due to industry-wide issues of falling grades, the need to reduce power consumption and fine grinding requirements.

Back to the original question, I expect Metso Outotec to be a strong player for dewatering and tailings management solutions.

IM: Outotec has a much more developed downstream business in areas like hydrometallurgy and smelting, etc in mining than Metso – will this remain a core part of the combined group?

SK: The front-end strength of Metso for mineral processing plants and the wet processing business focus of Outotec shows how well both companies complement one another. From a technical perspective, this is one of the reasons why the merger of Metso and Outotec makes much sense.

IM: In what segments of the mining and metals market do you see the most complementary solutions within Metso and Outotec?

SK: When we brought these two companies together it is amazing how many renowned international mineral processing experts came with it. We can provide much more comprehensive services to the industry because we can look at the entire flowsheet – from run of mine ore, to metal.

Why is this so important for our customers? You can bundle equipment together to make tenders and dealing with OEMs more economical for mining companies. But, more than that, we can bring a much larger pool of experts to a project to interact and talk with each other to provide the right innovations. This is the ‘one plus one equals three’ effect.

We can also look at balancing the equipment so, for example, the primary crusher is appropriately configured to produce the right ore for the secondary crushing process and the screens are amply sized to effectively carry out their job. That then leads to finding the optimal operating point for the HPGRs and milling equipment and then the downstream processing segment. This type of equipment balancing is highly interesting for the market, creating win-win situations for customers and us as an OEM.

IM: Do you see your relationship with mining customers changing because of this holistic approach?

SK: Yes and no. There are companies that will appreciate this wider offering and there are others that will continue to come to us as part of a more traditional way of tendering for mineral processing equipment.

I see a trend where larger companies are coming back to reliable OEMs because the availability, sustainability and reliability of equipment is much more important than saving a dollar in capex in the first place. That is a trend we have seen strengthen even more recently with COVID; we all know when a plant is not running, it costs operators hundreds of thousands of dollars per day in lost revenue.

Yet, there are always customers that say capex is king. They will do everything they can to tender it most competitively from a capital expense perspective, regardless of the long-term total cost of ownership benefits choosing another solution will have.

IM: How will your digital offering be strengthened through the combination?

SK: At Metso, we started, especially in South America, with a strong operation and presence in terms of remote control and remote operating and maintenance support for processing plants.

The service solutions that have been developed and established in some countries, specifically for Metso and for Metso equipment, in the new company will, of course, be transferred into the installed base of Outotec (for example, a facility previous owned by Outotec in Espoo, Finland, is now a Metso Outotec Performance Center facility).

We often heard from customers: ‘We have great equipment from the Outotec side, but we have never experienced the great Metso services.’

What is so encouraging to see is that there is demand from the industry for such a combination of equipment and services.

IM: Where do you see an overlap of solutions (for instance, possibly crushing and grinding equipment (SAG/AG/ball mills), vertical crushing tech (Vertimill/HIG mill)) or flotation (Outotec has a greater market share but Metso supplies some interesting options like column flotation, plus is the leader in flotation camera monitoring with VisioFroth)? Historically, have you been competing against each other for contracts in these market segments?

SK: As you know, for 12 months or so, there was intense scrutiny from the regulatory authorities to find out if the companies could merge or not because of an overlap, and the answer that came back is yes.

From a regulatory authority perspective, there is no overlap, and, from a technical perspective, I view it in a similar way.

One prime example to give would be the Vertimill (below, left) and the HIGmill (below, right). If you look at both in detail and you talk to customers – which has happened when we have our project meetings and negotiations – you often find that the applications being examined are so specific that both mills, although close when it comes to operating process, have their own sweet spots.

                      

Most of the cases where we, as Metso and Outotec, won or lost a tender, the argument was not around price or sentiment; it was always technical where, for example, the feed was too coarse for the HIGmill, or the end product needed to be so fine that the Vertimill was ruled out.

We, therefore, want to continue offering both technologies; we will not shelve one because we believe there is room for both solutions.

IM: Could this combination then enable you to offer a more customised solution for customers?

SK: That is where the benefit (from the combined Metso Outotec) for the industry really kicks in; our customers are not just getting standard solutions; some tailoring is involved. They will be able to get more specific and solution-oriented, performance-balanced pieces of equipment.

IM: Would you like to add anything else?

SK: I need to say that I am quite excited about the opportunities for the new company, Metso Outotec. There are benefits for both us and the wider industry.

Personally, I am humbled to be elected to run such a large organisation of industry experts and high-quality equipment. It is exciting times ahead.

Nordgold automates crushing and sorting ops at Suzdal

Nordgold says it has automated its crushing and sorting facility (CSF) at the Suzdal gold mine in Kazakhstan as part of the operation’s safety and production management improvement program.

The CSF uses a vibration feeder that distributes the ore evenly and feeds it into a jaw crusher, two cone crushers, vibration screens that screen for the required ore size, conveyor belts transporting the material, and a stacker. The facility processes around 550,000 t/y of gold-bearing ore.

Fully automating the facility means improved management and control of the ore crushing, milling and sorting process despite the increase in ore hardness, the company said.

Suzdal Plant Manager, Valery Pavlov, said: “CSF automation enables the operator to control key equipment parameters through the use of sensors. If the plant stops, the operator will see the root cause without leaving their desk. This makes the process more efficient and safer.”

Suzdal already employs BIOX gold processing at its operation, along with the innovative Outotec HiTeCC (high-temperature caustic conditioning) process.

“The new crushing and sorting automation technology will further improve the mine’s safety and processing performance,” it said.

Superior Industries deepens relationship with Kimball Equipment

Superior Industries, a US-based manufacturer and global supplier of bulk material processing and handling systems, has announced an expanded product partnership with its long-term conveyor dealer, Kimball Equipment Company.

The respected dealer, which celebrates 75 years of operation next year, will now sell, service and support Superior’s crushing, screening and washing equipment in addition to the conveying equipment and components lines throughout Utah, Nevada, Arizona and southern Idaho.

“Kimball Equipment is a well-respected company and we’re honoured they’ll represent our growing line of aggregate processing and handling equipment,” Jarrod Felton, President of Superior, said. “Together, we’re both excited to serve customers with the region’s best application advice, robust stocking plans and most efficient customer support.”

The relationship between dealer, Kimball Equipment, and manufacturer, Superior Industries, started in 2004. Since then, the Salt Lake City-based dealer has sold almost 1,500 Superior conveyors and thousands of idlers, pulleys and conveyor accessories, according to Superior.

Kimball Equipment offers an extensive inventory of new and used heavy equipment, parts and supplies, repairs and rebuilds, field service and engineering capabilities.