Progress in the understanding of leaching reactions and reactors

Leaching and dissolution are central to hydrometallurgical processes. Over the last quarter of a century, steady progress has been made in modelling of leaching reactors, with large tank and autoclave installations across the globe. At the same time, progress in understanding the mechanisms of dissolution of both economic and gangue minerals has been made. 

At next year's Hydrometallurgy '27, Dr. Frank Crundwell, of CM Solutions, South Africa, will survey this progress. Of particular importance are progress in three specific areas: 

1. there is a growing acknowledgement that the electronic structure of sulphide minerals is crucial;
2. a novel mechanism of the dissolution of silicates and oxide minerals has been proposed; and
3. a better comprehension of the dissolution of salts, such as gypsum and carbonates, has been achieved. 

The main concepts of these models will be described, and examples provided. 

Frank Crundwell graduated with degrees in chemical engineering from the University of the Witwatersrand, Between 1985 and 1990 he worked at Mintek, where he was seconded as an objector to military service under the apartheid government. He joined the faculty of the University of the Witwatersrand in 1990. In 1999, he joined Billiton and BHP Billiton Capital. In 2002, he established CM Solutions, an engineering consultancy, which has grown steadily. 

He received the Wadsworth Award of the SME in 2020 and the Gold Medal of the South African Institution of Chemical Engineers. He was elected to the prestigious US National Academy of Engineers in 2023, for his research on the mechanisms of dissolution.

We would also like to thank our latest sponsor to Hydrometallurgy '27, mining and metallurgical services consultancy Promet101, who are already kindly sponsoring Process Mineralogy '26, Critical Minerals '26, AI in Mineral Processing '27 and Flotation '27.  Promet101 owner and process engineering consultant Stuart Saich said "the contribution of MEI Conferences to our industry deserves our support".

#Hydrometallurgy27
#MEIBlog

July Cornish Mining Sundowner: news of progress at South Crofty

It was 25°C in Falmouth yesterday, ideal conditions for the well attended Cornish Mining Sundowner at the Chain Locker.

There was some talk of England's defensive retreat in their agonising World Cup semi-final 2-1 loss to Argentina on Wednesday and there was also news of progress in developing the South Crofty tin mine in Camborne. Front-End Engineering Design has been completed by Ausenco, and the project has moved into detailed engineering. This is a significant step before full construction.

Excavation for the pre-concentration plant is around 50% complete, with civil works expected to continue through 2026. The pre-concentration plant will remove waste rock by TOMRA sorters before ore enters the main processing circuit, reducing operating costs. Orders are being placed for long-lead equipment, and Cornish Metals Inc expects construction of the main processing facilities to follow the engineering work, with procurement continuing throughout 2026.

Paterson & Cooke is designing the paste backfill plant, which mixes mine tailings with binder so they can be pumped back underground. MEI is pleased to have this company as sponsors of Hydrometallurgy '27 and Flotation '27 in Cape Town.

The first commercial production at South Crofty is still targeted for mid-2028 and once fully operational, is expected to produce approximately 4,700 tonnes of tin in concentrate per year over an initial mine life of around 14 years, making it one of Europe's few primary tin producers.

The next Cornish Mining Sundowner is on Thursday August 20th, at the Chain Locker from 5.30pm.

MEIBlog

Mining in World History

I have just been re-reading the excellent Material World (posting of 13th March 2025) and noticed this time that the book Mining in World History was cited quite a few times. The author of Material World, Ed Conway, says that this is the best book that he has encountered on the history of mining, on copper but also a panoply of other materials.

Mining in World History was published in 2002 and authored by Martin Lynch, the son of Prof Alban Lynch. 

We are very fortunate to have Martin at Critical Minerals '26, where he will make a presentation arguing that substitution with aluminium may represent the most effective response to looming global copper shortages.

Mining in World History deals with the history of mining and smelting from the Renaissance to the present day, showing the interplay of personalities, politics and technology which have together shaped the metallurgical industries over the last 500 years. 

Martin opens with the invention, sometime before the year 1453, of a revolutionary technique for separating silver from copper, an event that revived the rich copper-silver mines of central Europe and the ruling ambitions of the Habsburg emperors who owned them. The flood of silver from Spain’s newly-conquered American colonies brought about the demise of these mines, and Martin then examines the far-reaching changes brought to mining and smelting by the steam engine and the Industrial Revolution. 

The book then looks at the era of the gold rushes and the comprehensive developments in mineral extraction and technology that took place in the United States and South Africa at the end of the nineteenth century, and describes the spread of mass metal-production techniques across the world amid the violent struggles of the twentieth century and the energy crises of the 1970s. 

Mining in World History was the first book to provide an account of how and why change and advance in this global industry have taken place in different eras and locations around the world. Ed Conway's Material World builds on this and the two books are highly recommended not just for those in the minerals industry, but for anyone with an interest in how the world works.

#MEIBlog

Process Mineralogy '26: programme now available

Monday's posting contained memories of Automated Mineralogy '06 in Brisbane, the first of three annual conferences held in Brisbane, before evolving into Process Mineralogy '10 in Cape Town. 

The process mineralogy series proved very successful and the 8th in the series will be held in Cape Town in November.

The full programme for Process Mineralogy '26, including abstracts and details of the presenters, can be found on the conference website, and a pdf of the timetable is also available.  

Over 40 presentation are scheduled over the three days, including two keynote lectures from Tassos Grammatikopoulos, of SGS Natural Resources, Canada and Lucas Pereira, of the Helmholtz Institute Freiberg for Resource Technology, Germany.

As with all MEI Conferences, time has been made available for networking. The long coffee and lunch breaks will be held in the exhibition area, and there is one exhibit booth still available for rental.

Lunch in the exhibition area at Process Mineralogy '24

The late afternoon sundowner will be held in the Vineyard Hotel gardens and the conference dinner at nearby Kirstenbosch Botanical Gardens, both great locations with a background of Table Mountain.

Sundowner at Process Mineralogy '24

Process Mineralogy '14 at Kirstenbosch

We thank our sponsors, Promet101, Hitachi, Capstone Copper, AECI Mining Chemicals, Petrolab and ZEISS  and our media sponsors International Mining and Minerals Engineering.

We look forward to seeing you at Process Mineralogy '26 and to Critical Minerals '26 which immediately follows. This video of Process Mineralogy '14 will show you what to expect if this is your first time at an MEI Conference in Cape Town.

#ProcessMineralogy26
#CriticalMinerals26
#MEIBlog

Memories of Automated Mineralogy '06, Brisbane

Twenty years ago this month the Hilton Hotel, Brisbane, Australia was the venue for MEI's inaugural Automated Mineralogy '06, a follow up to Applied Mineralogy '03 in Helsinki three years earlier. Organised in collaboration with Intellection with media partner the Gold & Minerals Gazette, this was the first of three annual conferences held in Brisbane, before evolving into Process Mineralogy '10 in Cape Town. 

Automated Mineralogy '06 brought together professionals concerned with the analysis and interpretation of mineralogical data using automated techniques, as well those involved with the development of hardware and software solutions to aid automated mineralogical analysis. The meeting attracted a wide spectrum of attendees including mineralogists, geologists, microscopists, process and mining engineers, analysts, business managers, and consultants. A total of 90 delegates representing nine countries attended the two-day conference at which 27 technical presentations plus exhibits from a number of key institutions and equipment suppliers, kept delegates informed. A full report was kindly supplied by Mark Pownceby, of CSIRO Minerals and selected papers were published in Volume 16 Issue 11 of Minerals Engineering.

A few surviving photos from the event are shown below:

#MEIBlog

Critical Minerals '26 programme now available

We are pleased to announce an outstanding programme for Critical Minerals '26 in Cape Town. The full programme, including abstracts and details of the presenters can be found on the conference website, and a pdf of the timetable is also available.

Thirty-nine presentations are scheduled over the two days, including two high-profile keynotes from Prof. Jacques Eksteen and Prof. Chun-Xia Zhao, the response being such that we have closed abstract submission, any abstracts now being received being put on a waiting list.

As with all MEI Conferences, time will also be given for socialising and networking, including welcoming and closing receptions and an informal conference dinner at the nearby Wild Fig restaurant, which impressed us at the recent Mineral Processing Circuits '26.

Dinner pre-drinks at the Wild Fig restaurant at Mineral Processing Circuits '26

There will be a very small exhibition at the conference, and one booth is currently available.  

Thanks to our sponsors Promet101, Capstone Copper, Petrolab and AECI Mining Chemicals, our media partners International Mining and Minerals Engineering and our industry advocate CEEC: Coalition for Minerals Efficiency.

#Critical Minerals26
#MEIBlog