Tag Archives: Kazakhstan

Seequent expands subsurface software presence in Central Asia with Kazakhstan hub

Seequent, The Bentley Subsurface Company, has announced the establishment of a regional hub in Kazakhstan, expanding its presence in Central Asia.

Staffed by a dedicated local team, the strategic move demonstrates Seequent’s commitment to providing cutting-edge subsurface software solutions to the rapidly growing local market and wider Central Asia region, it says.

Seequent shared the news last week at an event in Almaty, which brought together partners, stakeholders and leading industry representatives. Seequent has supported the Central Asian business community since 2011, and major companies in the region are already using Seequent’s earth-modelling, analysis, data management and collaboration software, the company says. These applications help users understand the underground in the mining, energy, civil infrastructure and environment industries.

Colin Hay, EMEA, Executive Vice President, EMEA with Seequent (pictured on the left with Inna Shalovenkova, Regional Sales Director, Mining and Minerals on the right), said: “Seequent’s expansion into Central Asia marks a significant milestone in our global strategy. Kazakhstan, situated in the heart of Central Asia, serves as an ideal hub for the region. With a robust economy, rich metal reserves, advantageous location and a focus on attracting foreign investment, Kazakhstan stands out as a key market for Seequent’s solutions.”

Hay added: “We are seeing a growing demand for our solutions that support the evolving needs of industries in this market seeking digital innovation to drive efficiency and value in their operations. We will continue to hire locally as our Central Asia operations expand.”

Seequent offers software solutions for geoprofessionals including geologists, geophysicists, geochemists, geotechnical and geomechanical engineers, hydrogeologists, ecologists, as well as builders, designers of structures, quarries and underground mine workers. Products include the geological 3D modelling solution Leapfrog and Oasis montaj for working with geophysical data.

Metso Outotec to deliver VSF X technology to Kyzyl Aray Copper project

Metso Outotec says it has signed an agreement with Kyzyl Aray Copper, a subsidiary of Caravan Resources, for the supply of copper solvent extraction and electrowinning technology for a plant to be built in the Karagandy region of the Republic of Kazakhstan.

The order of approximately €35 million ($37 million) covers a technology package delivery that includes the modular VSF®X solvent extraction plant and the main process equipment for the electrowinning plant.

Mikko Rantaharju, Vice President, Hydrometallurgy, at Metso Outotec, said: “We are looking forward to working with Kyzyl Aray Copper on this project. The energy-efficient VSF X solvent extraction plant, which is part of our Planet Positive product range, reduces emissions and is safe to operate.

“The Kyzyl Aray Copper project will become an important new reference for Metso Outotec in the growing Kazakhstan copper market as a supplier of a complete production plant that uses solvent extraction and electrowinning technology for copper recovery.”

Metso Outotec says its Vertical Smooth Flow (VSF) plants offer lower lifetime costs, significantly shorter lead times and sustainable life-cycle technology built on decades of experience in solvent extraction.

RG Gold looks to quadruple yellow metal output with new processing plant

RG Gold, majority owned Kazakh private equity group Verny Capital, has launched a new processing plant at its operations in Kazakhstan that is expected to enable the company to quadruple its gold output to circa-190,000 oz in 2023.

The new carbon in pulp plant, worth more than $420 million, has an annual processing capacity of around 5 Mt/y.

The new processing plant deploys modern equipment from global industry leaders, including Metso Outotec, thyssenkrupp, FLSmidth, Weir Minerals, Roytec and Kemix, RG Gold said.

RG Gold operates the RayGorodok deposit in northern Kazakhstan, one of the country’s largest mines with 5.9 Moz of JORC Code gold reserves. Its output is set to exceed 50,000 oz this year.

Bulat Utemuratov, the key investor in Verny Capital projects, said: “The launch of the new processing plant is a key milestone for RG Gold. It is underpinned by the highest global industry standards using the latest innovation and technical expertise from Resource Capital Funds, our strategic partner. The new plant allows us not only to quadruple RG Gold’s overall output, but importantly, it also provides the opportunity to boost investment in the region.”

FLSmidth to highlight full flowsheet expertise with ShalkiyaZinc project delivery

FLSmidth has signed a contract, valued at around DKK950 million ($130 million), to supply a range of mineral processing equipment to ShalkiyaZinc, the operator of a zinc-lead mine in the Kyzylorda Region of Kazakhstan.

The equipment will transform the plant into a world-class facility that efficiently separates minerals with a minimised environmental impact, the OEM says.

Under the agreement, FLSmidth will supply two underground crushing stations with a materials handling system to the process plant; a full package of comminution and separation equipment, including SAG and ball mills, mill circuit pumps and cyclones; the zinc-lead concentrate flotation and regrinding circuit, including nextSTEP, VXP vertical mills, concentrate thickeners and Pneumapress filters; and reagents preparation and dosing area. Full plant automation is also included, as well as installation and commissioning supervision services.

The new concentrator will be supported from FLSmidth’s new in-country service Supercentre in Karaganda, Kazakhstan.

The equipment delivery is to be completed during 2024, with commissioning to start before the end of that year.

Mikko Keto, Group CEO at FLSmidth, said: “We are excited to receive this first order from ShalkiyaZinc, which highlights our full flowsheet expertise. The wide range of equipment included in the order will help ShalkiyaZinc save on both capital expenditure and operating expenditure; our new nextSTEP flotation technology will improve the quality of the concentrates, the SAG mill will provide more flexibility, while the automation and digital solutions will further enable water and energy savings alongside safer operations.

“We look forward to making this a success on so many levels.”

Assel Rakhimova, Chief Project Director of Tau-Ken Samruk, which owns ShalkiyaZinc, said: “After testing and basic design work executed by FLSmidth, we are pleased to enter this new phase of collaboration with the procurement of critical technologies to improve the productivity and sustainability of our plant. We believe in successful execution and look forward to receiving the ordered equipment according to the schedule for installation and to continue working with FLSmidth on commissioning services and spare parts.”

Multotec supplies 38 slurry pumps to Kazakh chrome project

Mineral process equipment specialist Multotec’s global reach has recently been highlighted with the supply of slurry pumps to a chrome project in Kazakhstan.

According to Gerhard Hendriksz, General Manager, responsible for slurry pumps at Multotec, an order of 38 slurry pumps was delivered in mid-December 2021 through a collaboration of Multotec’s international business team and the company’s distributor in Kazakhstan.

“The pumps were produced according to the specifications provided by Multotec’s distributor, ensuring the units will deliver the required duty for the end customer,” Hendriksz said. “This includes being designed to withstand highly abrasive operating conditions.”

Certain chrome deposits in Kazakhstan boast some of the world’s highest concentrations of chrome oxide (Cr₂O₃) – up to 62% content – making the slurry particularly abrasive. The pump range Multotec delivered includes models from the HD25 to the MD300, in metal- and rubber-lined configurations to suit their respective duties.

A turnaround time of just 10 weeks was achieved, with Multotec leveraging its local supply chain that included foundry work, machining and other suppliers, as well as collaboration with Multotec’s technical partner, 7D, based in Perth, Australia.

Andre Burger, Production Manager, responsible for pumps at Multotec, emphasised that a close working relationship with the end user and Multotec’s Russian-speaking business team ensured smooth preparation and delivery.

“Our distributor has in-depth knowledge of the customer’s applications and has the engineering expertise to ensure optimal product specification and performance,” Burger said. “Multotec will support the products with aftersales and support services, including availability of spare parts.”

Despite the trade disruptions related to the COVID-19 pandemic, Multotec has continued to perform strongly on the export front. Last year, it earned a place in the Exporter of the Year Awards – presented by the South African Capital Equipment Export Council.

Multotec supplies a complete range of pumps for medium- and heavy-duty slurry applications, including cyclone feed, spirals feed, mill discharge, tailings disposal, filter feed, effluent discharge and spillage. The range caters for flow rates from around 15 cu.m/h up to 2,000 cu.m/h.

Repair, Reuse, Recycle: ERG’s critical minerals reprocessing journey

The Musonoi River Valley in the Katanga region in the Democratic Republic of the Congo (DRC) has, for some decades, been the site of land degradation resulting from inadequate and ineffective tailings and other waste management systems.

The local water system and surrounding land has been subjected to pollution from more than 83.2 Mt of legacy tailings spread over an area 11-km long and up to 2.5-km wide. Additionally, 41.1 Mt of tailings have accumulated at the Kingamyambo Tailings Dam.

Remediating and mitigating this damage is now a primary goal of Eurasian Resources Group’s Metalkol Roan Tailings Reclamation (RTR), a reprocessing facility dedicated to cleaning up the historic tailings left by previous mining operators in the Kolwezi area of the DRC. By reclaiming and reprocessing copper and cobalt tailings in the region, the company says its approach goes beyond ‘do no harm’, actively addressing a history of environmental degradation and pollution.

The legacy tailings are extracted through hydraulic mining and dredging, reprocessed and then re-deposited into a modern, closely managed and centralised tailings storage facility. This is subject to regular inspection, monitoring and reporting, supported by a dedicated Engineer of Record and an independent laboratory. Currently Metalkol RTR can produce 21,000 t/y of cobalt, which is says is sufficient for three million electric vehicle batteries, alongside around 100,000 t/y of copper, the company says.

ERG also has reprocessing operations outside of Africa, including at Kazchrome in Kazakhstan, which, it says, is the world’s largest high-carbon ferrochrome producer by chrome content.

Established in 2019, ERG Recycling – ERG’s specialised company aiming to become the largest entity to reprocess industrial waste into commercial products in Kazakhstan – has already implemented many projects including the commissioning of a new workshop that reprocesses slag, dust and other fine waste into high-quality briquettes. This program to reprocess Kazchrome’s 14.7 Mt of slag stockpiles has been expanded, now processing over 100,000 t/y of slag.

These operations have been enhanced by the development of new technology. Having completed the first trial in 2020, the Slimes 2 Tailings Reprocessing project at Donskoy GOK has the potential to enhance Kazchrome’s output of chrome concentrate by recovering 55% of the chromium oxide in chrome-oxide bearing tailings using innovative flotation technology, the company says.

In Brazil, at ERG’s integrated project, BAMIN, which produces a premium 67% Fe grade iron ore and is ramping up to become one of the country’s largest standalone iron ore exporters, the company’s transition from an upstream to a downstream tailings model ensured continued compliance with both local regulations and international standards, it said. The group continues to study additional technological enhancements to ensure the construction and operation of a world-class facility.

The environmental benefits of reprocessing projects like these are very significant for the business and critical to local communities, according to the company.

“As more attention rightly turns towards environmental, social and governance (ESG) issues, it is crucial that tailings are dealt with and stored properly,” ERG said. “Aside from preventing significant issues, such as dam collapses, by reprocessing and responsibly storing these tailings, we are reducing local pollution risks more generally, increasing air quality and decreasing the likelihood of leaching toxic substances into surrounding habitats and water systems.”

Given the legacy of environmental degradation and serious consequences it poses, it is also necessary for mining companies to explore novel ways of rehabilitating the environment.

For example, ERG has been working with a team of agronomists from the University of Lubumbashi in the DRC to look into the experimental planting of trees and their growing potential at the Kingamyambo tailings dam.

Looking forward, these operations will support the sustainable development of affordable batteries and other clean energy technologies.

By producing critical raw materials, such as cobalt, without the risk and cost of needing to develop new mining projects, ERG says it can help make electric vehicles and other renewable technologies more accessible, helping facilitating the net-zero transition.

Pictured above is Metalkol RTR, ERG’s reprocessing facility in the DRC: the world’s second largest standalone cobalt producer

NFC China, ERG agree on EPC contract to construct ‘special coke plant’ at JSC Shubarkol Komir

Eurasian Resources Group (ERG) and China Nonferrous Metal Industry’s Foreign Engineering and Construction Co Ltd. (NFC China) have signed an engineering, procurement and construction (EPC) contract to construct a “special coke plant” at JSC Shubarkol Komir in Kazakhstan’s Karaganda Region.

The new 400,000 t/y plant will produce a reducing agent that is key to the production of ferroalloys, ERG says.

Under the ЕРС contract, the plant will be constructed on a turnkey basis and is scheduled to be put into operation in 2023. Investments in the project will total about KZT40 billion ($94 million).

Ruslan Mulyukbayev, CEO of ERG Capital Projects, the company responsible for developing and implementing large-scale investment projects in Kazakhstan, said: “The new plant will enable JSC Shubarkol Komir to manufacture a high value-added product and cut the imports of reducing agents significantly. In addition, it should help increase local content in ferrochrome production and meet ERG’s needs by supplying a domestically manufactured product. The plant will use state-of-the-art technological solutions and automation that are fully compliant with all national standards. We plan to create 120 new jobs.”

Qin Junman, President of NFC, said: “The signing of the EPC contract marks another milestone in the long-term cooperation between NFC and ERG. I am fully confident that, with our good track record of successful implementation of a number world-class projects in Kazakhstan, including ERG’s state-of-the-art Aluminium Smelter project, we will be able to deliver another exemplary project of Sino-Kazakh cooperation within schedule, with good quality and with international HSE standard.”

In addition to 400,000 t of special coke, the new plant will produce more than 70,000 t/y of coal tar and oil from Shubarkol Komir’s coal. ERG is also exploring the possibility of exporting these products.

The new enterprise will use technological solutions to enable safe and environmentally friendly production, as well as to increase electricity, heat and water conservation, ERG says. Its ventilation system will be equipped with air purifiers. All water used in the production process, as well as the contaminated wastewater, will be treated and supplied to the water recycling system.

JSC Shubarkol Komir is already home to a special coke plant with a capacity of over 200,000 t/y that was built and put into operation in 2005. The company has implemented a project to equip the plant with the newest, most efficient system for tar removal from coke oven gas, a process which involves five-stages of treatment.

ERG to acquire Hitachi EH4000 AC-3 trucks, EX5600E excavators for SSGPO operation

Eurasian Resources Group (ERG) has signed a cooperation agreement with Eurasian Machinery LLP, the official provider of Hitachi specialised equipment in Central Asia.

The agreement will see 12 Hitachi EH4000 AC-3 dump trucks and two Hitachi EX5600E hydraulic excavators delivered this year to the Kacharsky open pit iron ore mine, part of ERG’s Sokolov-Sarybai Mining Production Operation (SSGPO), in Kazakhstan.

This stands as one of the most significant acquisitions of specialised mining equipment in Kazakhstan’s history, according to ERG.

The new equipment, boasting 220 t lifting capacity, will be used for overburden operations and the transportation of iron ore, and is part of a large-scale reconstruction of the entire Kacharsky site aimed at a considerable increase in iron ore production volumes at SSGPO, ERG says.

The delivery of the specialised equipment will offer remarkable increases in load capacity and provide further advantages when working on a large scale, according to the company.

In addition to delivering specialised equipment, Eurasian Machinery will perform a wide range of maintenance works, including the construction of service infrastructure and the supply of necessary spare parts over the next 10 years. They will also offer specialised simulator training to ERG’s drivers.

As part of the agreement, which will be carried out according to the maintenance and repair contract principles, ERG will purchase up to 50 units of specialised mining equipment.

Bentley’s cloud-based tech aids AAEngineering in Altynalmas gold plant design

AAEngineering Group, utilising Bentley Systems’ cloud-based technology, has helped Altynalmas come up with a new vision for a gold processing plant in Kazakhstan.

When drilling and geological studies revealed the presence of gold ores in the surrounding Akmola region, gold producer Altynalmas invested in expanding resource extraction operations, announcing a tender to increase annual ore processing production up to 5 Mt.

The $230 million project included construction of a new gold processing plant, a dam, accommodation camp for 600 people, water pipelines, and a 220 kV electrical substation.

AAEngineering Group was tasked with overall design, procurement, and construction works that required upgrading existing energy and mining infrastructure, ensuring environmental protection and occupational safety, and determining an optimal construction site that mandated a 1,000 m sanitary protection zone from adjacent pits and uranium dams. The new plant also needed to be interoperable with the existing processing facilities in terms of equipment and materials, as well as seamlessly integrate with the operating systems.

Additionally, AAEngineering faced challenges meeting the technology demands to comply with the client’s “Digital Mine initiative” on a tight timeline, compounded by coordinating a remote team during the COVID-19 pandemic.

The company wanted to offer several conceptual models to the client for Altynalmas to visualise the infrastructure design options and make the best decision for implementing the project.

“We needed to issue several versions of the project according to their technical inquiry,” Andrey Aksyonov, Director of the Information Modelling department at AAEngineering. This situation required updating the existing plant information model, creating a digital terrain model, and incorporating components from the database of equipment and materials to provide accurate visual options for the client.

Once the client decided on the optimal design concept and selected the location for the new plant, AAEngineering moved to the detailed design stage and proposed simultaneously executing design and construction works to reduce construction time and meet the short, 22-month deadline. It also sought provide seamless integration with existing facility assets and operations using digital twins.

To develop its conceptual solutions, concurrently perform design and construction, and achieve digital deliverables aligned with the client’s smart mining initiatives, AAEngineering required integrated BIM and digital twin technology. Furthermore, given the COVID-19 global pandemic quarantine, it needed to establish a connected data environment to remotely coordinate design and construction.

Beginning early in the conceptual modelling stage, AAEngineering established a collaborative design platform using Bentley Systems’ ProjectWise to provide a connected data exchange system for all contractors and the client. It used laser scanning and unmanned aerial vehicles (UAVs) to survey the existing facilities and the new construction site, processing the captured images with ContextCapture.

“From the survey data, they assessed earthworks and generated a digital terrain model in OpenRoads,” Bentley said. “Then, using OpenPlant, they digitised existing and new pipeline layouts and equipment connections to develop several conceptual 3D models for the client.”

Aksyonov explained: “Using the survey data in ContextCapture, we built a digital terrain model, and all this was transferred to the site layout plant to generate preliminary specifications with an assessment of earthworks.”

The client used the models to determine the optimal design concept and approve the plant location, equipment and piping scheme.

Based on the client’s specifications, AAEngineering used various software applications to assemble the pipeline and structural models, along with the accommodation camp. It then integrated these models with the general plant model in OpenBuildings Designer.

“Aligned with their proposal to perform design and construction simultaneously, AAEngineering used ContextCapture to process weekly UAV-captured images into reality meshes and synchronised the models with SYNCHRO 4D for construction simulation and scheduling,” Bentley said. “Incorporating LumenRT and iTwin Services facilitated visual clash detection and provided the cloud-based platform to establish a digital twin.”

Using Bentley’s digital twin technology, the company synced the model with iTwin for the best understanding, for visualisation of changes, and for making the right decisions on the project, Aksyonov said. These open applications helped maintain project control and stay on schedule throughout quarantine, the company said.

“Using Bentley technology during the conceptual phase resulted in a well-developed visual bid for the project, providing the client with a full understanding of the design right from the start and winning AAEngineering the contract,” Bentley said. “Throughout project execution, the integrated modelling applications and digital twin solution streamlined workflows and facilitated concurrent design and construction that reduced construction costs and allowed plant commissioning to be ahead of schedule.”

Working in a collaborative digital environment and updating the development model with UAV surveys saved 30% in design time and cut travel expenses by 75%, according to Bentley. This also optimised remote coordination and construction management during the COVID-19 quarantine. Accurate modelling and visualisation reduced material quantities by 15% and eliminated clashes during construction, it added.

“Lastly, using the digital twin, the client was able to train operations staff prior to plant commissioning,” Bentley said. “In addition, the digital twin enabled seamless integration with the client’s operating system in accordance with their digital mine initiative to support intelligent mining processes and management, promoting automation and digitalisation that are transforming the mining industry.”

For AAEngineering, implementing the use of digital twin technology on this project provided economic efficiencies and has instilled new corporate processes, making advanced digital practices a company standard, according to Bentley.

Aksyonov concluded: “To sum it all up, Bentley Systems enabled us to improve our own design, construction, and operations solutions.”

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