Mineral Processing Circuits '26: a summary of the technical presentations

Mineral Processing Circuits '26 was held at the Vineyard Hotel, Cape Town from April 23-24, 2026 and was attended by 46 delegates from 15 countries.

Following is a brief summary of the presentations delivered during the two days of technical sessions, with links, via the presenter's name, to the draft papers associated with each presentation. Accompanying photographs have been taken where possible from the conference photo album.

Unfortunately, not all presenters provided draft papers, so these presentations are not included in the summary. However, short abstracts for all the conference papers are available in the programme on the conference website.

The complete programme of presentations, including links to available draft papers, can be found in the online open-access Proceedings.

The draft papers have not been refereed, but all the presenters have been invited to submit their final papers for peer-review to a virtual special issue of Minerals Engineering.

Thursday April 23rd

Technical Session 1
Chairpersons: P. Miller (BacTech Environmental Corp., Canada) and A. Hubert (Köppern Aufbereitungstechnik GmbH & Co., Germany)

Kevin Galvin, Director of the ARC Centre Of Excellence, University of Newcastle, Australia is the inventor of the Reflux Classifier used in gravity separation of fine mineral particles. In his keynote presentation he argued that minerals processing is entering a paradigm shift, implying that there is a current paradigm, and that something new will ultimately emerge. He identified the existing paradigm, an approach forged on the back of 20th century technology and looked at understanding why it persists. In moving forward we need to consider the possibilities that arise from the emergence of new technologies. Up until now we have tended to consider new technologies and how they fit within the old paradigm, but the real innovation emerges when we let go of the past. He argued that complex, inefficient, large-scale plants should give way to simpler, efficient, smaller, more purposeful units or modules, that can be formally controlled to address variability and in turn facilitate more complex forms of decision making.

Kevin Galvin (left)

In the early stages of developing a new mining project, geometallurgical studies are crucial to assess the technical feasibility. Maria Cristina Vila, an Associate Professor at the University of Porto, Portugal, showed how this was used in the flowsheet design for the recovery of rare earth minerals from an iron-dolomite-carbonatite deposit.

Magnetic separation is commonly used in pegmatite ore processing to remove iron silicate minerals, such as amphibole and tourmaline, after dense media separation and/or flotation. Janine Figueiredo, of the Federal University of Ouro Preto, Brazil, presented a study evaluating how adding a magnetic separation step before dense media separation can improve the lithium grade in the concentrate during the beneficiation of spodumene-rich pegmatites.

Maria Cristina Vila (left) and Janine Figueiredo

Hagen Gunther Jung, Executive Director with GeoEnergy Consult, Germany, examined the various options for disposal of the naturally radioactive processing residues of a rare earths project.

Hagen Gunther Jung (left)

Richmond Asamoah, of the University of South Australia, discussed the influence of microwave pre-treatment on particle breakage and comminution efficiency of mineral ores.

Richmond Asamoah (right)

The Kanyika Niobium Project in Malawi re-evaluated its 1.5 Mtpa SABC comminution circuit due to high power consumption and high niobium losses to slimes. Rex Zietsman, Chief Technical Officer at Globe Metals and Mining, Australia, described the energy-efficient alternative comminution and beneficiation circuit for the Kanyika project.

Rex Zietsman (right)

Technical Session 2
Chairperson: G. Asbjörnsson (Chalmers University of Technology, Sweden)

Rex Zietsman was back on the podium after lunch showing how gravity-magnetic integration and selective regrinding has been used for pyrochlore recovery at the Kanyika Niobium Project in Malawi.

Scaling breakage parameters from pilot-scale SAG mill tests to industrial operations is complex due to non-linear relationship driven by internal classification and grate design differences.  Pablo Pichinao, a comminution specialist at Anglo American, Chile, proposed a phenomenological framework integrating pilot-scale test campaigns with industrial sampling to develop a robust scaling methodology. The approach establishes a scientifically grounded solution for translating pilot-scale findings to full-scale SAG operations, advancing comminution research and improving predictability in mineral processing circuits.

In a second presentation Pablo, and his colleague Sebastián Urrejola described the development and calibration of a phenomenological throughput model for the Quellaveco concentrator, a a state-of-the-art processing facility in southern Peru, part of Anglo American's digitalised open-pit copper mine. It uses high-capacity grinding (SAG/ball mills) and flotation to process around 127,500 tonnes of ore daily, producing copper and molybdenum concentrates.

Sebastián Urrejola (centre) and Pablo Pichinao (right)

Paul Shelley

Grinding media plays a large role in the energy and carbon emission story for hard rock mining. A presentation by Paul Shelley of Molycop Global, USA, makes a definitive contribution to the cast media carbon footprint discussion. Major emission contributors, scrap steel, ferro-chrome manufacturing, natural gas and electricity were discussed in detail, exploring the manufacturing route of cast media and its effect on the grinding media carbon footprint. The paper explored possibilities of reducing the grinding media carbon footprint at the customer site. Media in use options were presented that take account of the mineral characteristics, the mill dynamics, and the product metallurgy to optimise both carbon footprint and media performance.

High Pressure Grinding Rolls (HPGR) have become an integral part of flowsheets in mineral processing technology. Their proven advantages, such as low specific energy consumption, high availability, low operating costs, have led to an ever-widening range of applications for HPGR. As with the cement industry, where the use of HPGR began with simple pre-grinding,developments, the mineral processing industry ise also moving away from simple flowsheets with HPGR for pre-grinding towards more complex flowsheets in which HPGR performs the majority of the comminution work.  Artur Hubert, of the Koeppern Group, Germany, presented practical examples of successful HPGR application in grinding circuits in mineral processing and the cement industry and showed the versatility of HPGR use in flowsheets.

Artur Hubert

Taswald Moodley, Principal Engineer at Mintek, South Africa, described the repurposing of an existing stirred mill to improve PGM recovery in flotation circuits treating UG2 ore. UG2 is a chromitite reef with a shallow-dipping stratiform tabular orebody in the South African Bushveld Complex.

Taswald Moodley (right)

Friday April 24th

Technical Session 3
Chairpersons: T. Moodley (Mintek, South Africa) and A. Ojaghi (DRA Global, Canada)

Unfortunately Hongli Yang, of the Taiyuan University of Technology, China, although registered, was unable to attend the conference, but her paper describes the cyclone column separator (CCS), a novel kind of water-only cyclone characterised by compound positive and negative cone structure, which has been proved to be more efficient than traditional single-cone water-only cyclones and more cost-saving than dense medium cyclones in fine coal preparation. It has found wide application in China for coal preparation plants and also proved to be efficient in the carbon-ash separation of coal gasification slags

Process control and monitoring are essential strategies for improving profitability and minimising environmental impact in mineral processing. The effective implementation of these strategies is enhanced by sufficiently accurate dynamic process models. Although extensive literature exists on modelling mineral processing operations, they often differ in scope and complexity and are frequently presented inconsistently or incomplete. Moreover, many implementations rely on expensive software, hindering reuse and transparency. Conrad Kriel, of Stellenbosch University, South Africa,  presented a transparent, modular library that enables the integrated simulation of mineral processing systems. The library includes dynamic models for crushing, milling and flotation operations, presented in a consistent format.

Conrad Kriel (right)

A new approach on simulation of closed systems was described by Abu Huraira, of Metso, Finland. The new method allows optimisation of flotation residence times for each stage simultaneously. This can lead to improved metallurgical performance and decreased number of laboratory tests. Additionally, the proposed approach provides guidance on deciding appropriate laboratory residence times to be used as a design basis for upscaling to plant scale.

The Copperwood Project, located in Michigan’s Upper Peninsula, USA, has undergone a major process redesign integrating ultrafine flotation within a mill-float-mill-float circuit to enhance metallurgical performance and reduce energy demand. The revised flowsheet incorporates a de-sliming stage between milling circuits and Jameson Cell ultrafine flotation technology. Aghil Ojaghi, of DRA Global, Canada, showed  how the combined application of flowsheet modelling, equipment selection, and pilot validation can deliver step-change improvements in circuit performance, advancing the integration of modern flotation technologies to enhance recovery, sustainability, and operating efficiency in fine-grained copper deposits.

Aghil Ojaghi

Sands from the Ravno deposit, Slovenia, were characterised to evaluate their potential for high-purity quartz production, which is a critical raw material for EU industries. Kalyani Mohanty, a PhD student at Universitat Politècnica de Catalunya, Spain, showed how process development was focused on selective flotation using Clariant reagents, combined with gravity separation (Wilfley table and Multi Gravity Separators) to remove high-density impurities and upgrade the quartz to high-purity standards.

Kalyani Mohanty (centre)

Several critical factors define the performance of the flotation process. Among these, variability in the mineralogical characteristics, especially variabilities leading to galvanic interactions between the minerals’ surfaces and grinding media, are known to control and affect the selectivity and efficiency of the flotation process. Richmond Asamoah, of Adelaide University, showed that there is good association (linear and nonlinear) between the pulp chemistry variables and rougher feed mineral content, showing relevance to advanced sensor data before the grinding stage.

Technical Session 4
Chairperson: P. Shelley (Molycop Global, USA)

Varun Gowda

Design of aggregate production operations is often based on economic viability, while limited focus is on environmental viability. With an increasing demand for low environmental impact products (aggregates), there is a need to study the features and attributes in the design and operations of aggregates production that can achieve the same. Varun Gowda, of Chalmers University of Technology, Sweden, provided a benchmark analysis of multiple aggregate production sites in Europe based on their annual site-specific data, operational characteristics (resource consumption, production, etc.), and design characteristics (machines, process layout, etc.).

Reprocessing of phosphate mine waste has become essential due to the depletion of primary resources, the growing demand for phosphate ore, and increasing concerns about the environmental impacts of waste storage. However, its development remains challenging because of the heterogeneity of these materials, arising from their lithological variability, particle size distribution, and mineralogical complexity. Mohamed Haidouri, of University Mohamed VI Polytechnic, Morocco, presented an innovative solution for transforming mine waste into a sustainable secondary resource. The approach is based on the development and comparison of mineral processing circuits to select the most efficient configuration that maximizes phosphate recovery while meeting marketable quality criteria. The proposed flowsheets integrate classification, sorting, grinding, desliming, reverse flotation, and direct reverse flotation. 

Mohamed Haidouri

In recent years, refractory low-grade ores serve as a major source of gold. The ever-increasing ore complexity warrants smart online process adaptation and development of advanced methods for sustainable, cost-effective gold extraction process. Richmond Asamoah, of Adelaide University, investigated technological challenges linked with gold extraction from refractory, auriferous sulphide ores outsourced from a common deposit but with subtle short-term variability. The changing mineral composition and the dynamics of pre-concentration and pre-treatment techniques (e.g., flotation and bio-oxidation) in maximising the leaching performance were investigated. The findings highlight the critical importance of advanced sensor and smart process adaptation for complex variable ore processing.

Millions of tonnes of flotation tailings worldwide contain significant residual metal values locked within sulphide minerals that are uneconomic to process using conventional methods. Paul Miller, of Bactech Environmental Corporation, presented a novel process integrating bioleaching with ammonia-based chemistry to recover critical metals while converting iron and sulphate streams into magnetite and ammonium sulphate. The generation of these by-products provides additional revenue streams as opposed to waste streams that can significantly offset metal recovery costs, supporting the economic viability of total tailings reprocessing.

Paul Miller (right)

High pressure acid leaching (HPAL) is widely applied for nickel and cobalt recovery from lateritic ores using sulfuric acid under elevated temperature and pressure. However, the subsequent counter-current decantation (CCD) circuits used for solid-liquid separation are characterised by high water demand,large footprint, and potential metal losses. Richmond Asamoah, of Adelaide University, showed that the resin-in-moist-mix (RIMM) process has high efficiency in recovering valuable metals from pulps and fine minerals. Integrating RIMM into the CCD circuit following HPAL offers a novel strategy to enhance metal recovery while reducing water and reagent consumption. Introducing ion-exchange resin after the first CCD stage enables selective adsorption of dissolved metal ions, decreasing dependence on multiple wash stages and minimising solution losses.

A final thanks to all those who presented their work at the conference, and we hope to see you all again at Mineral Processing Circuits '28. Reactions to Mineral Processing Circuits '26 can be seen at #MineralProcessingCircuits26.

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