Sensor based electronic sorting proves itself yet again

We can expect electronic sorting to feature in next year's Comminution '25 conference, as X-Ray transmission sorting has become the process of choice for the pre-concentration of crushed ore prior to grinding.

Basic electronic sorting has been around for some time now, being first introduced in the late 1940s with fairly limited applications. Way back in 1979 it gets a mention in the 1st edition of Mineral Processing Technology with a diagram showing a typical sorter of the time, in which the ore was fed in a monolayer, as display of individual particles to the sorting device was essential. Things have progressed a great deal since then with  multi-layer beds and sensors to manage all kinds of ore properties.

1970s ore sorter

Originally their main use was for sorting diamond ores, making use of the fluorescence of diamonds under a beam of X-rays, and I remember my visit to the Premier Diamond Mine at Cullinan in South Africa in 1978, when a few months earlier the recently installed electronic sorter had picked up its first major find, the 353.9 carat Premier Rose. 

The Premier Mine was famous for the largest gem-diamond ever found, the 3106 carat Cullinan Diamond, prised out of the mine face in 1905. Last week there was news that Canada’s Lucara Diamond has recovered the second largest diamond ever found, at 2,492 carats, from its Karowe mine in Botswana. It is the largest diamond ever recovered by a mechanical process.

Lucara diamond

The diamond was detected and recovered by the company’s Mega Diamond Recovery (MDR) X-ray Transmission (XRT) technology, installed by TOMRA in 2017 to identify and preserve large, high-value stones. A computer processes the data gathered from the scan and creates a series of images that identifies individual stones by shape and density. If the density is close to that of a diamond, as the ore falls off the end of the belt, a jet of air blows the candidate into a collection bin.

According to the company, MDR XRT is particularly good for sorting out large, gem-quality diamonds and has already found some exceptional stones, including the 1,758-carat Sewelô diamond and the 1,109-carat Lesedi La Rona. It reinforces the unparalleled value XRT offers not only diamond mining companies but many other operations, making it arguably the most important mineral processing development in recent years.

Negative publicity does not help the skills shortage

As the world transitions to green energy the role of the mining industry increases in importance in supplying the minerals needed for renewables and electric vehicles.

But also of increasing importance, and a major worry, is the need to recruit bright young people into the industry. Many young people are shying away from choosing careers in the mining sector due to negative perceptions of the industry, mining often being perceived as dangerous and dirty and associated with oil and gas. A 2023 McKinsey Report revealed that 70% of young participants said they would definitely or probably would not work in mining with many saying they believe it does more harm than good!

The mining industry should be an attractive option for young people, due to its generous salaries, abundant opportunities, and an overall great career path. However, regardless of the opportunities, there remains a tarnished image of mining careers among young people. And not just young people: a recent article in The Times describes the new career path of former Conservative Foreign Secretary Dominic Raab, who has left politics to take on a role with a private equity firm helping the West lay its hands on the critical minerals needed to achieve net zero. It is an interesting article but what hit me was the statement from the author, who has a BA in History, that rather than cutting big-money City deals, Raab has plumped for the "distinctly unglamorous world of mining".

This is typical of the negative approach to mining adopted by the media and I doubt that the many young people that I meet, who have spent a few years in the industry, regret not having taken up opportunities in the more glamorous areas of banking and accountancy.

The future is in their hands- Camborne School of Mines students at a recent Cornish Mining Sundowner

I am looking forward to the keynote lecture Critical Skills for Critical Minerals, from Diana Drinkwater, of Metecelerate, Australia, at the IMPC in Washington, who will show how the mining industry is currently riding a wave of opportunity generated by new technologies, and how it is encouraging to see policymakers around the world highlighting the importance of a secure supply of so-called critical minerals and making some startling predictions about the increasing demand for these minerals. Diana will show how it is encouraging to see an acknowledged need for investment in education, not only in mining and exploration activities but in the opportunities in concentration, extraction and purification of minerals and metals.

Last year in the USA the Mining Schools Act of 2023 was introduced and on July 10th the bill made its way to the House of Representatives after passing through the Senate. The act aims to boost the ability of mining schools to train and recruit individuals, as well as support studies, research projects, and demonstration projects to shape the nation’s future generation of mining experts. To do so, it will establish a grant program for mining schools, authorising $10 million for each fiscal year from 2024-2031. 

"The passage of the Mining Schools Act will enhance our recruiting efforts as it provides a specific point of reference to students and their parents, explaining why entering our programs is important to our country", said Michael Moats, professor of metallurgical engineering at Missouri University of Science and Technology.

According to figures from the Society for Mining, Metallurgy & Exploration (SME), there has been an estimated 43% decrease in the number of graduates since 2015, with geological engineering programs dwindling to only 13 and metallurgical engineering at eight. Although these numbers highlight a steady decline in industry interest, the Mining Schools Act provides hope for its future.

Here in the UK, the reinstatement of the mining engineering degree at the Camborne School of Mines will allow school leavers to pursue a career in the industry, and coupled with CSM's existing MSc in Mineral Processing a great career path into mineral processing will be available.

There is an urgent need to work either directly with young people through schools or target them through a social media marketing campaign. By showing the diverse roles and opportunities available and the positive impacts of sustainable practices being made, the industry can not only attract, but also empower the next generations.

The future of our resources sector depends on how we engage with the innovative spirit of young people. Without their fresh perspectives and innovative thinking, we risk stagnating in a world that demands progress.

Rapid leaps in AI methods are accelerating comminution modelling

In recent years, artificial intelligence has been revolutionising many fields, including comminution, by predictive modelling, AI driven calibration, optimisation and process control or via the use of surrogate models. 

By building quick to apply digital twins of experiments, simulations or translations of both, iteration speeds can be leveraged by orders of magnitude.  Very recently, in addition to these narrow AI systems, specialising on one task only, another kind of general purpose AI, of much greater impact, is emerging. 

Many researchers see these generative AI systems such as large language models (LLM) or large multi-modal models as well as diffusion models, as early examples of the holy grail of AI research, Artificial General Intelligence (AGI).  

In a keynote lecture at Comminution '25, Carsten Schilde, Heisenberg-Professor at TU Braunschweig, Germany, will give an overview of both narrow AI as well as general purpose AI, showing practical examples of surrogate and predictive models as well as LLM and agent based systems in comminution.

Prof. Schilde is the 2019 holder of the Friedrich Löffler Award in recognition of outstanding achievements in the field of particle technology, particularly in the area of experimental and digital methods and in relation to technically relevant particle systems.

#Comminution25

MEI keynote speakers honoured by keynotes at IMPC 2024

Only six weeks now before IMPC 2024 commences in Washington and MEI is proud to be a media partner for the event. Leading the technical sessions will be 14 keynote speakers and I am pleased that half of these have been keynote speakers at MEI Conferences.

Megan Becker is MEI's consultant to the process mineralogy series of conferences. She leads the geometallurgy and process mineralogy research activities in the Centre for Minerals Research, and the Minerals to Metals Initiative in the Department of Chemical Engineering at the University of Cape Town. In 2018, Megan was nominated as one of the top 100 Global Inspirational Women in Mining, having numerous academic and industrial collaborations on projects in geometallurgy, process mineralogy, flotation and comminution, hydrometallurgy, and environmental mineralogy. 

Megan will be co-authoring two papers at Process Mineralogy '24 and at Process Mineralogy '22 in Spain she gave a keynote on the contribution of mineralogy to sustainability in the mine life cycle. At the IMPC she will present a keynote on the importance of process mineralogy and geometallurgy in enabling the energy transition.

Megan with Norman Lotter at Process Mineralogy '22

Diana Drinkwater, of Metcelerate, is a mineral processor with over 30 years’ experience in mining operations, engineering and consulting. Her principal interest is professional education and technology transfer, and she has delivered targeted education programmes in Australia, Africa, the Americas and Europe. She has served on the board of the Australian Institute of Mining and Metallurgy  and currently chairs the Education Commission of the International Mineral Processing Council which is overseeing a global review of Mineral Processing education. She presented a keynote lecture at Flotation '23 and at IMPC her keynote will address the critical skills needed for production of critical minerals.

Diana Drinkwater (centre) with her Metcelerate colleagues,
Jenny Wiese and Katja Freitag at Flotation '23

Kevin Galvin, of the University of Newcastle, Australia, is the inventor of the Reflux Classifier and the Reflux Flotation Cell. His numerous awards include the Ian Wark Medal, ATSE Clunies Ross Award, and the SME's Antoine Gaudin Award. He has presented keynote lectures at MEI's Physical Separation '09 in Falmouth, and at Physical Separation '22, which was online due to the pandemic. At IMPC he will look at the application of the Boycott Effect in maximising grade and recovery.

Kevin Galvin (right) at Mill Circuits '24 with the team from FLSmidth,
the service provider for the Reflux Classifier and Reflux Flotation Cell

Kym Runge

Another MEI conference which was held online due to Covid was Flotation '21 and a keynote lecture by Kym Runge. leader of the Separation Research Program at the SMI-JKMRC, Australia discussed developments in flotation circuit diagnostic practice. At IMPC Kym will discuss advances in flotation which have the potential to address the challenges associated with the energy transition.

Jacques Eksteen, of Curtin University, Australia,  has been a regular contributor to many MEI Conferences and was a keynote speaker at Precious Metals '15 in Falmouth. His keynote lecture at IMPC will look at the development of sustainable hydrometallurgical technologies for critical minerals and precious metals, focusing on glycine. In the photo below, taken at Precious Metals '15, Jacques Eksteen (right) is talking to Corby Anderson of Colorado School of Mines, USA (centre) and Dave Dreisinger of the University of British Columbia, Canada. Dave Dreisinger will also be a keynote lecturer at the IMPC, discussing new strategies for recovery of nickel and cobalt for a low carbon future.

Ted Bearman and his wife Claire are good friends who I have known since their student days at Camborne School of Mines.

With Ted and Claire at Asia-Pacific 2022 in Melbourne

Ted presented a keynote lecture at Comminution '12 in Cape Town, and at IMPC his keynote lecture will be "Changing the Face of Comminution – Insurmountable Hurdles or Just Speed-humps on the Journey"?

Finally, I must mention Pablo Brito-Parada, of Imperial College, UK,  who will present a keynote at the IMPC on advances in model predictive control for flotation. Although he has never presented a keynote at an MEI Conference, he fulfills a very important role with all the conferences as Editor-in-Chief of Minerals Engineering, a position that he took over from me at the end of 2022. In this role he also acts as editor of the special issues of the MEI Conferences, which are published online via ScienceDirect.

Pablo Brito-Parada (2nd left) at Computational Modelling '19 in Falmouth

A full listing of all 14 keynote lectures at IMPC 2024 can be found on the congress website.

August Cornish Mining Sundowner: alumni surprises and news of South Crofty progress

Despite the Cornish mizzle, there was an excellent turnout at last night's Cornish Mining Sundowner, at Falmouth's Chain Locker,  with welcome appearances of several Camborne School of Mines mineral processing alumni.

With CSM mineral processing alumni Nick Wilshaw (1980), Phil Moore (1982),
Pete Flitcroft (1984), Jim Turner (1984) and Dave Wardle (1984)

It was good to see Mike Hallewell back at the sundowner, having missed the last few due to pressure of work. He is a busy metallurgical consultant, involved with Eloro Resources in Bolivia and, closer to home, the revival of South Crofty tin mine. He told me that progress is being made with the new mill flowsheet at South Crofty based on practical experience operating the historical circuits before the mine closed in 1998 and incorporating modern technologies that have evolved in the interim period.

With Mike Hallewell

The original flowsheet used dense medium separation (DMS) as a preconcentration method; the proposed flowsheet will likely use a combination of DMS and XRT ore sorting. After coarse grinding via a rod mill, spiral concentration (previously used at South Crofty Mill) will be used to remove coarse liberated cassiterite prior to ball milling, with Mozley Multi-Gravity Separation (C902 MGS) units replacing shaking tables in the finer size fractions, as the capacity and efficiency of shaking tables decreases with decreasing particle size. The original fine tin flotation circuits were technically challenging and sensitive to pulp temperature and water chemistry so a study is currently underway to look at a simpler and lower cost gravity roughing stage using Falcon Continuous Concentrators, followed by C902 MGS cleaning. 

Mike was the longest serving Mill Superintendent at Wheal Jane (1991-1998) where he oversaw the metallurgical developments in 1993 which brought the tin recoveries to record highs that were the envy of the world. He is very proud and delighted to be back as part of the Cornish Metals team, which continues to progress work plans and accomplish key milestones, particularly the completion of the Preliminary Economic Assessment of the South Crofty tin project that confirms the Project’s potential to be a low-cost and long-life tin mining operation. Mine dewatering is still proceeding, with treated water being discharged to the Red River exceeding the standards permitted by the Environment Agency. The priority and focus is on advancing South Crofty towards commencement of production in 2027.

It was a great Sundowner last night, and the next one, at the Chain Locker, will be on Thursday September 19th.

Four high profile plenary speakers for the IMPC in Washington

The XXXI International Mineral Processing Congress (IMPC) is now only seven weeks away. Covid severely disrupted the sequence of these biennial events, the last IMPC being held in Moscow in 2018, so it will be good to be in Washington for IMPC 2024 which will draw together the world’s leading experts to promote and discuss the latest advances in the science and technology of mineral processing. 

The structure of global energy supply and demand is undergoing a dramatic transformation with shifts towards renewable and alternative sources of electric power and the electrification of transportation and this will be reflected in the high profile plenary and keynote lectures which will supplement the 409 technical presentations and posters over the 4 days.

Of the four plenary lectures, which will be held on the morning of Monday September 30th, I particularly look forward to that of Richard Williams, I first met Richard in 1986, when he attended the NATO Advanced Study Institute in Falmouth. He was then a Research Associate with Imperial College, UK, but it was obvious even at that early stage that he was destined for great things and I had the pleasure of interviewing him for the blog in 2015.

Prof. Williams is Principal and Vice-Chancellor at Heriot-Watt University, Scotland and his plenary lecture will examine a delivery pathway to sustainable minerals processing, looking at the future impact of research and innovation. The following month he will be in Cape Town to further develop this theme at MEI's Critical Minerals '24. He is pictured below at SRCR'11 in Falmouth with Prof. Markus Reuter, who will immediately precede Richard's presentation at Critical Minerals '24 with his opening keynote on fundamental limits of the supply chain of critical metals and minerals within the circular economy.

Richard Williams and Markus Reuter in 2011

The British Geological Survey (BGS) will be represented at Critical Minerals '24 with a presentation on graphite-rich metasediments. At the IMPC, Karen Hanghøj, the first female Director of the BGS, will show in her plenary lecture how mineral raw materials are important for society in general, and for the transition to a green economy in particular. They are key for achieving the goals set out in COP21 and for achieving several of the United Nations Sustainable Development Goals.

Karen Hanghøj

Despite Metso being a regular sponsor of MEI Conferences I have never met Markku Teräsvasara, who is the President Minerals and Deputy to the CEO at Metso Corporation (formerly Metso Outotec Corporation). In his plenary presentation Markku will show how maximising process circuit productivity requires a systematic and methodical approach as well as breaking away from conventional thinking. By integrating key elements such as optimised sustainable flowsheets, high-performance process equipment, digitalisation, and automation, substantial improvements can be achieved. 

Markku Teräsvasara

In the fourth plenary lecture Mallory Clites, Technology Deployment Manager with the United States Department of Energy, will discuss batteries, critical mineral supply chains and the energy transition.

Mallory Clites

There is much to look forward to in Washington next month, the first IMPC in the USA since 1995 in San Francisco.

Frothers: from fundamentals to practice

Frothers provide three key functions: maintaining small bubble size, reducing bubble rise velocity, and contributing to froth stability. Studies have linked these functions to frother structure. The first two will be the focus of a keynote lecture at Flotation '25 by Jim Finch, Hatch Professor Emeritus in Mining and Metallurgical Engineering at McGill University, Canada. 

Bubble size is tracked by critical coalescence concentration (CCC) and rise velocity by the concentration at minimum velocity (CMV). Both measures will be briefly explained and CCC and CMV shown to be related. Two theories help link to frother structure, the Marongoni effect and the hydration effect. Including impact of molecule conformation and H-bonding on molecule transport either theory provides an explanation. For alcohols, as an example, the link shows an advantage of branched over straight chain structures. Hydration theory does have an advantage: through ordering water it provides an interpretation of why different size bubbles can rise at the same speed dependent on frother type. Evidence that the volume of water carried per bubble varies with frother type will be presented, water transport aiding froth stability and influencing frother choice.

Jim Finch is one of the most well known figures in mineral processing, being ranked #3 in the world by ScholarGPS. MEI is proud to have him as a consultant to the flotation conferences and I had the pleasure of interviewing him for the blog in 2015. A graduate of Birmingham University, UK, he has been associated with McGill University since 1973. He is the co-author of two books Column Flotation (1990) and 8th Edition of Wills’ Mineral Processing Technology (2016). 

Among his many awards are the SME Antoine Gaudin Award and the IMPC Lifetime Achievement Award and he is currently a CIM Distinguished Lecturer, an honour he holds for the second time. He was General Chair of the XXVIII IMPC, Québec City, 2016.

Jim Finch with Lucas Pereira at Flotation '23

#Flotation25

Forty-four mineral processors in top 0.5% of all scholars worldwide. But how seriously should we take these ranking lists?

This is an update to the posting of 9th May where four mineral processors were listed in the top 0.05% of all scholars worldwide, the so-called Highly Ranked scientists who are the most productive in terms of number of publications and whose works are of profound impact (citations) and of utmost quality (h-index), and have ScholarGPS ranks of 0.05% or better. 

ScholarGPS is a California-based company that applies artificial intelligence, data mining, machine learning, and other data science techniques to its massive database of over 200 million publications and 3 billion citations to rank over 30 million scholars worldwide. The data used to rank the Scholars weight each publication and citation by the number of authors, excluding self-citations. Using AI removes the possibility of bias often associated with human assessments.

ScholarGPS has now published a wider list of Top Scholars by Expertise, the top 0.5% ranked scholars, and 44 mineral processors are in this list, although not all of the affiliations are accurate! 

Congratulations to all concerned, but how seriously should we take these rankings? An article in The Times 3 days ago highlighted the online profile of Larry Richardson, a young mathematician with significant potential. According to Google Scholar, a website widely used to evaluate academics for jobs and promotions, he had produced a dozen research papers in the past four years, which had been cited by his peers scores of times. His career appeared to be blossoming. 

There was just one issue: Larry was a cat! In fact, he was the most highly cited feline in the world of academia, thanks to an experiment designed to expose long-standing flaws in how researchers are ranked, the fake profile exposing flaws in the Google Scholar website that allows scientists to fraudulently boost their credibility.

The story began when Reese Richardson, a PhD candidate at Northwestern University in the US, and Nick Wise, a research associate at the University of Cambridge, spotted services being advertised on Facebook that promised to boost the careers of scientists by fraudulently inflating their standing on Google Scholar. They worked out that these  fraudsters were using easily available software to generate sham research papers, which were then uploaded to ResearchGate, a well known social media platform for academics. 

These papers consisted almost entirely of nonsense, but they also included citations of studies purportedly produced by the fraudsters’ customers. When Richardson and Wise realised that Google Scholar was recognising these bogus papers and citations as legitimate, they marvelled at how easy it seemed to be to game the system. It might even be possible, speculated Wise, to transform a family pet into a rising academic star.

So, what do you think of ranking lists? Should we take them seriously?

July summary: political history and a glimpse of dystopia

July was a momentous month in the UK's political history, when after the general election of July 4th Labour overturned 14 years of Conservative rule with a massive landslide victory, making Sir Keir Starmer the 7th Labour Prime Minister and the 7th Prime Minister to serve the UK in the past 14 years.

King Charles officially appoints Sir Keir Starmer as Prime Minister

What was particularly remarkable about Labour's huge majority was that 5 years previously Boris Johnson's Conservatives had effectively wiped out Labour with its own huge landslide victory. Down here in Cornwall, the Conservatives held all six seats on July 4th. One day later they had none, four going to Labour and two to the Liberal Democrats, who became the 3rd place party with the highest number of MPs in 100 years.

Let's now hope that Labour's promise of change is one for the better. Maybe a good omen: Sir Kier Starmer is the first Prime Minister to have graduated from my alma mater, Leeds University, and his deputy leader, Angela Rayner is the MP for my home town of Ashton-u-Lyne!

And political history was made across the Atlantic when former President Donald Trump escaped death by millimetres when a bullet from an intended assassin scraped his ear at a Republican convention. Citing "divine intervention" his popularity soared above his Democratic rival, President Joe Biden, who stepped down from the Presidential race a week later due to failing health and endorsed his vice president, Kamala Harris, as Trump's opponent in the election contest.

Just when you think you have seen everything: Trump supporters the day after the shooting

Sporting history was made in July when the England Men's football team reached a major final for the first time on foreign soil. After a very dull start in the tournament they came alive in the semi-final of Euro 2024 to beat The Netherlands 2-1 to take them to Berlin and the final against Spain. But all credit to Spain, who were the better side and proved worthy of their 2-1 victory, England failing at the final hurdle as they did 3 years ago against Italy in Euro 2020 in London, which was delayed a year due to Covid. Spain had much to celebrate on July 14th, as a few hours before their football victory 21 year old Carlos Alcaraz demolished Novak Djokovic in the Wimbledon tennis final, denying the Serbian his 25th Grand Slam victory.

We were lucky in June to have unseasonable winter sunshine in Cape Town for Physical Separation '24 and Mill Circuits '24, but the weather a few weeks later in July was horrendous with torrential rain and flooding in the area around the Vineyard Hotel.

Flooding at Newlands, Cape Town

And July was pretty miserable here too, but we managed to dodge the rain and drizzle in the middle of the month with family visitors from Luxembourg and northern England.

Matt: The Telegraph

At the Chain Locker, Falmouth: Barbara, Amanda and son Will and my sister Pat and her husband Bill

At home with Amanda and sons, Jon and Kathryn and family and Barbara's sister and husband

My dystopian nightmare has always been a total collapse of the world's computer systems, caused by massive solar activity or a malicious cyber attack, and on the 19th of the month the world's biggest ever computer outage grounded thousands of flights, stalled banking and healthcare services, and badly hit other sectors. The cybersecurity firm, CrowdStrike, was responsible for the worldwide outages, a minor software update affecting many MS Windows users and providing a strong warning of how fragile our digital world is, our total reliance on electronics to sustain society and our daily lives.

Summer bloomed again on the last week of the month and Barbara and I made use of the hot and sunny weather to visit the surf capital of the UK, the bustling tourist mecca of Newquay, 25 miles from Falmouth on Cornwall's north coast. It is noisy and crowded in summer, but we found  tranquility in a one and a half mile walk from the busy harbour in the town to Fistral, the country's number 1 surfing beach.

Newquay harbour

Approaching the famous Headland Hotel at Fistral beach

Fistral beach

En route to Fistral we passed the historic Huer's Hut, thought to date from the 14th century. The hut was used by a huer at the time of year when shoals of pilchards were expected in the bay, a call on his horn raising the hue and cry alerting the townsfolk to the arrival of the fish. The hut also made history in 1967 when it was used as one of the locations for the Beatles Magical Mystery Tour during the group's 3 day stay in Newquay.

The Huer's Hut: with (right) George Harrison and John Lennon and crew members in 1967