Thursday, 6 February 2025

Comminution '25 update: check out the delegate list

Comminution '25 is now only 7 weeks away, and already over 130 delegates from 24 countries have registered. The delegate list is now on the conference website and this will be updated regularly. As you will see, there is a fine mix of academia, operators and service providers.

The conference programme is now finalised, but we are still considering abstract submissions for poster presentation. Posters will be displayed in the main exhibition area, where coffee and lunch breaks take place. There will be 23 booths in this area and another 7 small booths outside the conference room. All exhibition space is now sold out.

Poster displays at Comminution '23

Although we have a packed timetable over the four days, there will be plenty of time for networking during the long coffee and lunch breaks, the evening sundowners and the conference dinner at Groot Constantia Wine Estate.

Conference sponsor Glencore Technology will run a workshop, "Expanding the capability and application of the Isamill", on the afternoon of Sunday 30th March, immediately before the conference welcoming reception.

The Coalition for Minerals Efficiency (CEEC) will also be running a full day workshop on Sunday 30th March, on "The future of comminution". 

So join us in beautiful Cape Town next month- a conference not to be missed for anyone with an interest in comminution. And Cape Town itself is an added bonus. The UK-based consumer organisation Which? asked more than 1500 of its members to rank their experiences of cities outside Europe. Of the 35 cities surveyed Cape Town came on top.

Monday, 3 February 2025

Recent comments

There have been comments on the following postings since the last update.

Health and safety could stifle scientific inspiration
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Friday, 31 January 2025

January summary

The first week of January rarely provides much professional news, but there was good news from Scotland on the first of the month, when we heard that my old friend and former Camborne School of Mines colleague, Prof. Richard Williams, was awarded the CBE in the New Year's Honours list. Commander of the Order of the British Empire is an award given to people who have made a significant contribution to the country and to their area of activity. The CBE is the highest ranking Order of the British Empire excluding a knighthood or damehood and is one level up on the OBE (Officer of the Order of the British Empire) an award which Richard has also held since 2009.

Richard is Principal and Vice Chancellor at Heriot-Watt University, UK and I first met him in 1986 in Falmouth at the NATO Advanced Study Institute Mineral Processing at a Crossroads. Richard was then a research associate at Imperial College, just after being awarded his PhD. I have followed his meteoric career progression since then and we were pleased to see him at Critical Minerals '24 in Cape Town last November, where he delivered an excellent presentation. Many congratulations, Richard, on a well deserved award honouring an outstanding career.

Richard with Barbara and me at Critical Minerals '24 dinner at Groot Constantia wine estate

The professional world awakened again in the second week of the month, after its festive slumber, but it was a week of natural disasters and chaos. Much of the UK was covered in snow, and heavy rains caused severe flooding, leading to more than usual travel chaos on road and rail. But this was nothing compared to the earthquake in Tibet, which led to major loss of life, and the apocalyptic wildfires in California, which devastated the Los Angeles area with major loss of property and lives.

West Cornwall tends to miss such extremes and our thoughts were mainly on the next MEI conference, Comminution '25, with its record number of papers, and a major exhibition, with all 30 booths sold by the end of the first week of the month. We are pleased that Glencore Technology and CEEC are running workshops on the afternoon before the conference welcoming reception. Two regulars who will be sorely missed are Sam Palaniandy, who died last May (posting of 6th May 2024) and John Starkey, who died earlier this month (posting of 15th January 2025).  John's memorial service is in Oakville, Ontario today.

All efforts are being made to ensure the success of Comminution '25, and of Flotation '25 in November, and it is a bonus that, due to the internet, we can live and work anywhere in the world.  In the middle of the month Amanda took herself off to Thailand for a 10 day working holiday, keeping in touch daily with me in Cornwall and Jon in Luxembourg, while enjoying the warmth.

On the 20th of the month Donald Trump was once more unleashed on the world, beginning his term as 47th US President by pledging a boost in fossil fuel production, vowing to withdraw the US from the Paris climate agreement, the world's most important effort to tackle rising temperatures. The US will now join Iran, Yemen and Libya as the only countries to currently stand outside the agreement, which was signed 10 years ago in the French capital. Trump's ignorance of the agreement was echoed in his statement in 2017 that he had been elected to represent the people of Pittsburgh and "not Paris". The following months should be interesting!

Monday, 27 January 2025

Does gold mining have a place in the green transition?

Way back in 1978 I descended 12,000 feet underground in the world's deepest mine, Western Deep Levels gold mine in Carletonville, South Africa. The miners toiled under arduous conditions, the temperature of the rock reaching 66°C at the greatest depths, slurry ice being pumped underground to cool the tunnel air to below 30°C. Due to the enormous pressures, rock bursts, the sudden and explosive failure of the rock mass near excavation boundaries, were a constant threat and the constant creaking of the rock was a little concerning.

Western Deeps 1978

Even then, in my early days in mining, I felt it bizarre that enormous efforts were being made to extract gold from the bowels of the earth in order to produce gold ingots which were stored underground again in vast vaults, such as those at Fort Knox, which I was very familiar with having seen Goldfinger several times.

Some thirty years later I voiced my concerns about gold mining in the first year of the blog (How do we argue the case for gold mining?). As everything we use is either mined or grown, it is easy to argue the case for mining most commodities, but I did not find it so easy for gold.

Until 2006 South Africa was the world's leading gold producer, in 2022 it languished in 10th place, China now leading the field, producing around 10% of global total gold production, which in 2023 was over 3000 tonnes. 

Source: World Gold Council

The vast majority of the gold mined today has relatively little practical use. Only about 10% of the world’s gold demand comes from industry, where it is used primarily as an efficient, corrosion-proof conductor of energy, mainly in electronic equipment such as computers and smart phones, and in dentistry. About half of the current gold in the world exists as jewellery, with the other roughly 40% hoarded in coins and bullion by investors and central banks. The US Geological Survey estimates that around 57,000 tonnes of gold are still waiting to be mined, but my question is why mine it?

At least 10% of global gold production comes as a by-product of base metal mining, mainly from copper and to a lesser extent from lead mining and this is sufficient for industrial use.   This implies that the output from gold-only mines produces metal only to satisfy the needs of the jewellery and investment businesses. 

Do we need more gold for storing in vaults? According to the World Gold Council 212,000 tonnes of gold have already been mined and 22% of this is is stored, so 47,000 tonnes is already stored in vaults. In the 2009 posting there was a report that Swiss banks were running out of secure storage space for gold bullion held by investors and institutions in their vaults. One Swiss bank reported that it was having to relocate some of its stored silver bullion to another site to make room for gold. 

Jewellery can be made more sustainable by alloying gold with other metals, as is the case with 18 karat gold, commonly used in jewellery, which is 18 parts gold and 6 parts other metals, commonly silver and copper.

The environmental impact of burning fossil fuels is well known, but fossil fuels are essential to the green transition. However the mining of gold ores also has a huge environmental footprint. Gold ores have the lowest grade of all mined metals, the average grade being between 5 and 8 grams of gold per tonne.  This is 0.0008% Au, so around half a billion tonnes of rock has to be mined annually. The energy required to mine, comminute and process this vast amount of rock is enormous. It has been estimated that gold mines emit more greenhouse gases than all passenger flights between European nations combined. 

Gold mining generates more waste than any other metal. If not properly managed, tailings can potentially affect soil, water, and air quality. They can leak toxic substances, including acid mine drainage, into the environment. Billions of cubic metres of contamination have been released since cyanide heap leaching emerged in the 1970s. 

There is much gold in waste electronic and electrical equipment (WEEE), which with more efficient recycling practices could contribute to the gold needed outside industrial use.  The recovery process can be challenging, as it often involves dismantling devices and carefully extracting precious metals from tiny components. Advances in WEEE recycling technologies are improving recovery rates, but there's still a lot of room for growth.

The minerals industry has a skills shortage and many talented mining and minerals engineers are involved with gold mining and processing, who might be better employed elsewhere, enhancing the recovery of truly critical metals and minerals and moving civilisation to the goal of a circular economy by seeking ways to facilitate recycling.

There is 100 times more gold in a tonne of smartphones than in a tonne of gold ore. It is estimated that there are around 7 billion smart phones in existence, and over 1.5 billion new ones are produced annually. Estimates suggest that over 150 million smartphones end up in landfills each year globally and many are stashed in desks and drawers, due to the high turnover rate of smartphones, with many devices discarded when users upgrade to newer models.

WEE contains critical and essential metals such as gallium, germanium and indium, which are all by-products of base metal mining, particularly zinc mining. Will we ever see a day when we say that gold, an essential metal in electronics, is also produced only as a by-product of the mining of base metals, particularly copper?

I doubt it! This is all very idealistic of course. I am sure that the allure and insatiable quest for gold, which has endured for millennia, will continue. There are very cogent arguments for gold mining, which contributes substantially to the socio-economic development of its host communities and countries. Value is created and distributed in many ways, including through employment, local procurement, tax revenues, enhanced infrastructure and better access to healthcare and education. With responsible management and investment, it can help drive growth and development while improving the lives of local communities. The lives of many artisanal miners in poorer countries are dependent on gold mining, although illegal artisanal gold mining is the biggest single source of mercury contamination in the environment.

But I will always feel uneasy when someone asks me to justify gold mining! It must rank as one of mankind’s more futile occupations, much of the gold that is dug up so expensively being destined to be buried somewhere else.

Barry Wills, MEI

Thursday, 23 January 2025

Kemtec Africa the latest sponsor of Flotation '25

In 2017 we were pleased to announce that Kemtec, a new Australian company, supplying specialty flotation reagents to tackle plant challenges, was to sponsor Flotation '17 in Cape Town. Two years later we welcomed the young company back as a sponsor of Flotation '19.

The company has grown since then and is now a global group of specialised mineral processing reagent companies, located in USA, Australia, Mexico and China, with Kemtec Africa servicing the African continent.  In 2021 we welcomed Kemtec Africa as a sponsor of Flotation '21, an online event due to Covid, and the company then sponsored Flotation '23 in Cape Town.

We are very pleased to have Kemtec Africa on board once again, as a sponsor of Flotation '25. We are currently calling for abstracts for the conference, which should be submitted via the online portal by the end of May.

"I would encourage all those young and not so young mineral processors with a passion for bubbles to put their fingers to the keyboard and write an abstract for Flotation 2025 in Cape Town. This conference is renowned for bringing academics and industry together to discuss the science of mineral froth flotation- an event not to be missed!"
Dr. Chris Greet, Global Mineral Processing Specialist at Magotteaux, Principal Consultant at Mineralis Consultants and Adjunct Associate Research Professor at University of South Australia.

Monday, 20 January 2025

Exploring Mpumalanga

South Africa is one of the most beautiful and geographically diverse countries on earth, and there are many options for exploring after an MEI Conference in Cape Town. 

One of the country’s most interesting and beautiful regions is Mpumalanga, formerly the Eastern Transvaal. Mpumalanga (Zulu name for "the place where the sun rises") is a province in eastern South Africa, bordering the nations of Eswatini (formerly Swaziland) and Mozambique. It lies north of KwaZulu-Natal (see posting of 25 November 2024) and in the northeast the land rises towards the peaks of the Drakensberg mountains and then terminates in an immense escarpment. In some places this escarpment plunges hundreds of metres down to the low-lying area known as the Lowveld.

After MEI Conferences in Cape Town in 2009, Barbara and I flew from Cape Town to Mpumalanga's capital Nelspruit (now Mbombela), rented a car and based ourselves at Sabie, from where we could easily explore the main attractions of the province, particularly the Panorama Route, a scenic road that connects many natural and cultural attractions, and ends at the border of Mpumalanga and the Limpopo province. 

There are more waterfalls around Sabie than anywhere else in Southern Africa so it is worth spending a few days visiting some of them and hiking some of the trails leading to them.

Only 9 km from Sabie on the old tarred road is the Lone Creek Falls, only a short walk through a beautiful indigenous forest. The waterfall has been declared a National Monument, and reaches 68 m.

The Horseshoe Falls are also along the Sabie River and although not very high, they have been declared a national monument.

Lone Creek and Horseshoe Falls

Further north, on the Mac-Mac River, the Mac-Mac Falls plunges 70 m into a deep pool, and can be approached by a 2km walk from the Mac-Mac Pools.

Mac-Mac Falls

Just off the Panorama Route are the  Berlin and Lisbon falls. 

Berlin Falls cascade from the centre of a sheer cliff that stands roughly 80m tall. Berlin Falls gets its name from miners who ventured to South Africa from Europe during the gold rush, and named each waterfall in the region after their home towns, or places from their home countries.

Berlin Falls

Nearby is Mpumulanga's highest waterfall, at 94 m, the Lisbon Falls, one of the most dramatic and scenic waterfalls in the region, situated on a tributary of the Blyde River.

Lisbon Falls
Relaxing by the Blyde River

A short distance east of the Berlin and Lisbon Falls is God's Window, which has inspired and awed thousands of painters and photographers from all over the world. A very steep stepped footpath along the edge of the escarpment leads to the actual view points, where the cliffs plunge down 700m, with views over the Lowveld to the Kruger National Park and towards the Lebombo Mountains on South Africa’s border with Mozambique.

God's Window

The Blyde River Canyon is the 3rd largest canyon in the world, after the Grand Canyon and Namibia's Fish River Canyon.  It begins 35km from God's Window at the bizarre natural water features of Borke's Luck Potholes, one of South Africa's major tourist attractions. They are the result of thousands of years of swirling eddies of water where the Treur River meets the Blyde River, the tumult of which has caused extensive water erosion,

Blyde River Canyon and Borke's Potholes

Perhaps saving the best to last, the Panorama Route end with the Three Rondavels, three round mountains with slightly pointed tops, very similar to the traditional round or oval African homesteads called rondavels. The viewpoint is spectacular, looking over the canyon to the Three Rondavels on the other side of the northern edges of the Drakensberg range of mountains. 

The Three Rondavels tower approximately 700 metres over the surrounding countryside and their distinctive shapes are the result of erosion, soft, underlying stone being whittled and washed away by the weather, leaving the tougher slate and quartzite layers visible.

Mpumalanga is not only beautiful, it also has a rich mining history. Gold was discovered in the province in 1883 in the mountains surrounding what is now Barberton, well worth a visit although 100km south of Sabie. The town is set in a basin surrounded by the oldest mountains in the world. The Mkhonjwa Mountains date back 3.5 billion years, with some of the oldest exposed rocks, volcanic in origin, known as the Barberton Greenstone Belt. A bacterial micro-fossil, the first form of life on earth, was found here and has been identified as being 3.2 billion years old.

Gold was found  here in 1883, and in 1884 Graham Barber discovered an incredibly rich gold reef, which created the famous 'Barberton boom' as miners flocked to the area.  Gold was also discovered in the hills above Barberton, and in 1885 the Sheba Reef Gold Mining Company was formed. The Sheba mine is still in operation, the oldest and richest gold mine in South Africa. However Barberton flourished for only a brief period, as in 1886 the Australian prospector George Harrison stumbled upon the giant Witwatersrand gold-bearing reef, which made all other deposits pale into insignificance. The miners moved on to the new town of Johannesburg, and South Africa's 20th century world dominance in gold mining had begun.

Barberton

The first large-scale production of gold began when alluvial deposits were discovered at Pilgrim’s Rest. After it was officially declared a gold field in September 1873, the town suddenly grew,  but In the 1880s the alluvial gold dwindled and prospectors were attracted to Barberton's newly discovered gold deposits.

Pilgrim's Rest is certainly worth visiting as it is only 35 km north of Sabie. Now a restored gold mining town museum it is peaceful and photogenic but in 1873 1500 diggers worked 4000 claims in grueling and unhygienic conditions.  Many of them died from malaria and dysentery after arduous treks through the Lowveld, some passing over the giant gold reef which slumbered under their feet, and would be woken a decade later.

If all this isn't enough to encourage you to visit Mpumulanga, Kruger National Park, one of Africa's largest game reserves, is only 87 km away from Sabie (see Travels in Limpopo).

Letaba River, Kruger National Park
Oliphants River, Kruger National Park