Soft Sensors for Decision Making in Comminution and Classification Circuits

According to Prof. Mohsen Yahyaei, a keynote lecturer at next year's Comminution '27, modern comminution and classification circuits are increasingly constrained not by a lack of data but by limited visibility into the variables that truly matter for decision-making and optimisation. Many critical states, such as mill total and ball filling, cyclone water and mass split, and circulating load, remain difficult or impractical to measure directly and reliably online. 

Prof. Yahyaei's keynote will be an overview of model based soft sensors and dynamic circuit models developed at Australia's JKMRC and deployed at an industrial scale. Using examples from SAG, ball and vertical mills, and hydrocyclone circuits, he will illustrate how soft sensors can provide robust, interpretable estimates of internal process conditions in real time. The integration of these soft sensors with dynamic models of materials handling into control rooms and advanced control systems demonstrates how enhanced process visibility and ore tracking lead to better operational decisions, improved stability, and reduced reliance on manual measurements. The presentation will highlight lessons learned from deployment, the role of dynamic modelling in closing the loop between measurement and control, and the pathway toward more autonomous comminution circuits.

Mohsen Yahyaei is Director of the Julius Kruttschnitt Mineral Research Centre (JKMRC) at the University of Queensland. He leads research and industry partnerships spanning comminution, mineral processing, and process automation, with a focus on making grinding circuits more efficient while remaining robust to ore variability. His work combines integrated ore-to-concentrate modelling, advanced sensing and soft-sensor development, and decision-support layers that translate plant data into actionable operating strategies. Prof. Mohsen’s interests include comminution classification, model-based optimisation, and practical deployment of AI and automation in safety-critical operations. He works closely with site teams and technology partners to bridge the gap between laboratory insight, simulation, and sustained plant improvement. 

At JKMRC, he also contributes to professional training and mentoring of higher-degree researchers, translating fundamental understanding into tools that deliver measurable throughput and sustainability gains. He is active in global communication forums and promotes collaboration on benchmark data, models, and best practices. He said "This (Comminution '27) is a timely forum to challenge how we think about grinding and comminution systems, not as isolated unit operations, but as ore-driven, data-informed decision systems that must remain robust under extreme variability."

#Comminution27
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February summary: Winter breaks and sad goodbyes

January had been an awful month in Cornwall with three major storms causing much devastation (January summary) so Barbara and I took ourselves off to the Spanish island of Tenerife in the first week of this month for a 10 day break in the sun and respite from the endless rain and wind.

We stayed at Los Gigantes, a small, quiet town on the west coast of the volcanic island, famous for its dramatic basalt cliffs called Acantilados de Los Gigantes, which rise 500-800 metres out of the Atlantic. To early sailors and to the island’s original inhabitants, these cliffs looked like enormous stone giants guarding the coast and Tenerife’s pre-Spanish inhabitants believed the cliffs marked the edge of the world.

Los Gigantes

Tenerife's volcanic landscape with Mount Teide, at 3715 m,
the highest point of any island in the Atlantic

Sunset over La Gomera, 15 miles from Tenerife
on the right is the Canary island of La Palma

Jon meanwhile escaped the Luxembourg winter to enjoy a few days gentle skiing with his daughter in the French Alps, before returning home for a minor leg operation, which precluded his attendance at the SME Annual Meeting in Salt Lake City, although he will be fit for April's Physical Separation '26 and Mineral Processing Circuits '26 in Cape Town.

This is the first year that I have missed the annual SME event since 2008. After 23 SME Annual Meetings I passed the baton on to Jon, but his withdrawal  meant no MEI representation this year. Hopefully Jon will be at the meeting in Denver next year.

Grandson Will continued his South American adventure. He and his girlfriend Liv, were in Peru for the first half of the month, taking in some of the famous sites

Acclimatising in Cusco

Above Machu Picchu and at 5036m on Rainbow Mountain

From Peru they flew to Canada then on to Tokyo! It's turning out to be an epic journey, so far Brazil, Paraguay, Argentina, Uruguay, Peru and Japan, with Malaysia and Indonesia next on the list.

Meanwhile Amanda has been in the county all month, enduring the endless rain, but managing to get out on the Helford River regularly to train for the upcoming World Gig Championships in the Isles of Scilly.

The passing of an old friend is always a reminder of your own mortality, and early in the month I heard the sad news that my closest friend throughout my six years at Leeds University had died at the age of 81. Bob Schofield and I shared a flat in Headingley during our undergraduate days and then we went on to spend a further three years of PhD research, after which Barbara and I took off to Zambia, and Bob and his wife Jean to Newcastle upon Tyne, where Bob spent six years with British Gas researching into the materials used for gas transmission, distribution and production. He then spent many years travelling around the world, working on major oil and gas pipeline projects in the UK, France, Netherlands and the Middle East, before becoming an independent pipeline consultant. He was still working when we met for the first time in 44 years in 2013, when he had no plans to retire. Our thoughts are with Jean and family.

Barbara and me with Bob and Jean in Leeds, 1967 and London 2013

There was also sad news of the death of pioneering mineral processor Roger Amelunxen, who I first met at Flotation '15 in Cape Town, where he and his son Peter represented their family business, conference sponsor Aminpro.

Roger and Peter (3rd and 4th left) at Flotation '15

I met Roger briefly again in Phoenix in 2024 and I am pleased that he was able to see Peter receive the SME's prestigious Antoine Gaudin Award (posting of December 22nd 2024).

Roger was 77 years old and there is little that I can add to Peter's excellent appreciation of his father on LinkedIn. Our condolences to the family.

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We welcome COMEX as a sponsor of Physical Separation '26

Electronic sorting is increasingly important in mineral processing because it enables the early separation of valuable ore from waste rock, which is especially critical as ore grades decline and energy costs rise. By rejecting barren material before energy-intensive crushing and grinding, it reduces power consumption, operating costs, water and reagent use, and the volume of tailings produced, improving both economic efficiency and environmental sustainability. Advances in sensor technologies and real-time data analysis now allow accurate, high-throughput identification of mineral composition, making pre-concentration and the profitable treatment of lower-grade or more complex deposits possible.

We are pleased to have three leading players in this field as sponsors of Physical Separation '26. Steinert came in early, followed by TOMRA (posting of 21 July 2025) and our latest sponsor is Polish industrial machinery manufacturer COMEX, that develops and sells sensor-based sorting systems and powder-processing equipment for mining, processing plants, chemical operations and recycling applications. COMEX was also a sponsor of Physical Separation '24.

COMEX founder and CEO, Jacek Kolacz, said "The main reason for sponsoring the Physical Separation series is to enhance Comex Group visibility among the decision makers and mineral industry experts.  Sensor based sorting is steadily increasing in number of applications and bringing huge benefits in many aspects, so it is critical to reach the widest possible audience during the conference or the exhibition and through other news channels. It also provides more possibilities for building proper networking, which is necessary to connect with professionals and investors in a collaborative environment. Mineral processing is still the conservative area and sponsoring conferences like this one, where new technologies are well emphasized, can only help in making new complex equipment to be more common in the future".

Jacek Kolacz (centre) at Physical Separation '24

Registration is open for Physical Separation '26 and one exhibition booth is still available for rental.

Full programme details, including abstracts, can be found on the conference website and a timetable is available in pdf format.

#PhysicalSeparation26

February Cornish Mining Sundowner with visitors from far afield

A tremendous turnout last night for the February sundowner at Falmouth’s Chain Locker, helped by a welcome break in the relentless rain.

Camborne School of Mines alumni were out in force, with visitors from outside the county, and two from as far away as Malaysia and Kazakhstan.

There is usually a good student presence at the Chain Locker, as it is only a few miles from the Camborne School of Mines in Penryn.  This week, however, they were involved with other activities, as CSM has been holding an International Student Week, with Mining and Geology students from across Europe coming here to explore the School of Mines, gain insight into the projects currently underway in Cornwall and experience the overground and underground activities our region has to offer. Students have been at CSM from International Federation of Mining & Metallurgical Students member institutions in Norway, Belgium, the Netherlands and Finland. The visits have been organised by Harry McTiernan, an Engineering Geology and Geotechnics student at CSM, who provided this photo taken early in the week in Falmouth.

Welsh company Maelgwyn Mineral Services (MMS) has been involved with MEI Conferences, particularly comminution and flotation, for many years and are sponsors of next year's Comminution '27 and Flotation '27. It was great to catch up with Chairman Mike Battersby and General Manager Steve Flatman last night. They are down from Cardiff to visit GT Jones in St Austell, specialists in designing, engineering and manufacturing process equipment, to look into the manufacture of the MMS Ro-Star ultra-fine grinding laboratory and pilot mills. The USA patent has now been granted for the Ro-Star mill concept, and in conjunction with Ersel, a Turkish mill manufacturer, MMS has just completed the construction of a 500kW Ro-Star mill for an industrial application. Mike and Steve are also meeting with Cornwall based Simon Bailey, of Comminution '27 sponsor Global Met Tech, who is helping with testing and scale-up of the Ro-Star, together with advice on the best ceramic grinding media to use.

With Mike and Steve

Finally, it takes big money to start up a mine so very good news that Cornish Metals has received a non-binding Letter of Interest from the Export-Import Bank of the United States outlining potential financing support of up to US$225m for the South Crofty tin project.

The next sundowner is at the Chain Locker on Thursday March 19th, from 5.30pm.

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The SME Annual Meeting in Salt Lake City is only a week away

The MEI blog began in February 2009. That same month, Jon and I attended the Society for Mining, Metallurgy and Exploration (SME) Annual Meeting in Denver, with snapshots from the event appearing in the February blog posts.

Jon and I at the Elsevier booth in Denver, 2009

The following year in Phoenix, I started writing annual reports on the SME meetings and have covered every one since, up to last year’s meeting in Denver (MINEXCHANGE 2025). That event may mark my final visit to the USA, and at next week’s Annual Meeting in Salt Lake City Jon was hoping to represent MEI, but unfortunately due to a minor operation he has had to pull out.

So I regret that there will be no MEI report and photos from this year's meeting but if you have news and photos that would be of interest to mineral processors, I would be grateful if you could pass them on. I particularly regret that we won't be able to photograph the Mineral Processing Division Award Winners this year:

Antoine Gaudin Award: Jan Cilliers
Milton E. Wadsworth Award: Ronel Kappes
Robert H. Richards Award: Rob McIvor

or the AIME's Frank Aplan Award winner James Gebhardt

The nearest I can get is photos from previous SMEs:

Jan Cilliers (2024), Ronel Kappes (2024), Rob McIvor (2022), Jim Gebhardt (2022)

Congratulations to you all. 

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The crucial importance of process mineralogy

It should go without saying that all mineral processors should be interested in the mineralogy of their ore because mineralogy directly controls how the ore behaves during processing. The type of minerals present, their grain size, associations, and degree of liberation determine the choice and efficiency of comminution, separation, and extraction methods. Mineralogy influences recovery, concentrate grade, reagent consumption, energy use, and the generation of deleterious elements or penalties. A sound understanding of ore mineralogy allows processors to predict processing challenges, optimise plant design and operating conditions, and respond effectively to ore variability, ultimately improving metallurgical performance and economic outcomes.

MEI’s Process Mineralogy ’26 is important because it brings together mineral processors, mineralogists, researchers, and equipment suppliers to focus on the critical link between ore mineralogy and processing performance. The conference provides a platform to share the latest advances in process mineralogy tools, techniques, and case studies that demonstrate how detailed mineralogical understanding can solve real plant problems. By highlighting how mineralogy influences recovery, efficiency, sustainability, and risk management across the mining value chain, the conference helps bridge the gap between geology and metallurgy, supports better decision-making, and promotes more efficient, cost-effective, and environmentally responsible mineral processing operations.

Process Mineralogy ’26 is relevant to a wide range of professionals who are involved in, or influenced by, ore characterisation and processing, including:

• Mineral processing engineers and metallurgists seeking to improve recovery, grade, and plant performance.
• Process mineralogists and geometallurgists working to link mineralogical data with processing behaviour.
• Geologists and exploration professionals interested in understanding how ore characteristics affect downstream processing and project value.
• Plant operators and technical managers responsible for managing ore variability and operational risk.
• Researchers, academics, and students focused on mineral processing, mineralogy, and related disciplines.
• Equipment manufacturers and technology providers offering analytical tools, software, and processing solutions.
• Consultants and project developers involved in flowsheet design, feasibility studies, and optimisation

Process Mineralogy '26 is followed by Critical Minerals '26 and there is likely to be a fair amount of overlap between the two conferences. One of the keynotes at Process Mineralogy '26 will deal with process mineralogy for critical metals in mineral processing and extractive metallurgy and the two conferences have an advisor in common, Prof Alan R. Butcher of ButcherGeologica.

#ProcessMineralogy26
#CriticalMinerals26
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