Monday, 10 May 2021

Flotation '21: Call for Abstracts

We still live in a time of great uncertainty, but whatever happens over the next few months, we have absolute certainty that Flotation '21 will take place in November, either as a hybrid event, or totally online.  If hybrid, authors will have the option of presenting live in Cape Town, between November 8-11, or submitting recorded presentations for viewing online. In any case, all presentations will be available on demand for 6 months after the event, via the conference website.

There is now a call for abstracts, which must be submitted online by the end of August. Authors will be notified of decisions on papers during September.

After the conference authors will be invited to submit their papers for peer-review for possible publication in Minerals Engineering. Papers will be handled exclusively by me, as the journal's Editor-in-Chief, and I will take into account discussion at the conference and effectively fast-track the reviewing process.

If your paper is accepted for publication after refereeing, it will be published immediately in the first available regular issue of Minerals Engineering, and included in the Virtual Special Issue of the conference on ScienceDirect. This is an ideal opportunity to present your work to an international audience and have your paper published in a refereed journal of high repute.

We would like to thank our sponsors, who have supported us throughout these difficult times, and welcome two new sponsors, who will be involved with an MEI flotation series conference for the first time.

Newmont is a sponsor of next month's Biomining '21 and is the world's largest gold mining company, with gold mines in Nevada, Colorado, Ontario, Quebec, Mexico, the Dominican Republic, Australia, Ghana, Argentina, Peru, and Suriname. In addition to gold, Newmont mines copper, silver, zinc and lead.

Cancha was one of the sponsors of last month's Comminution '21. Cancha is an integrated solution for geometallurgical sample selection, result interpretation, prediction modelling and reporting and is used by geologists, miners, metallurgists and geometallurgists to accurately, efficiently and transparently project metallurgical performance for mineral resources. Its unique geostatistical functions are used to ensure that samples are representative. Advanced data science is used to propose domain and regression models for parameters such as recovery, concentrate grade, and tonnage.

Current sponsors

Prof. Jim Finch, Emeritus Professor of McGill University, Canada, has been a long-standing consultant to MEI's flotation series, and we were proud to announce last year that he was the recipient of the IMPC's 2020 Lifetime Achievement Award. Jim will present a keynote lecture at Flotation '21 on the appreciation of the life and work of Prof. Graeme Jameson, of the University of Newcastle, Australia, also a holder of the Lifetime Achievement Award and a regular contributor to the flotation series.

Graeme and Jim at Flotation '15

Few can claim a process or equipment that carries their name. The Jameson Cell is a rare example: an industrial endorsement of Professor Jameson’s already secured academic reputation that sets him apart. Taking the Cell as the unifying theme, Jim's talk will assess Graeme’s contributions to the technology of flotation, from fundamental models and innovative experiments to his continuing quest for the universal flotation machine.


Sunday, 9 May 2021

Prof. D.V. Subba Rao, 1954-2021

Sad news from India of the death of Prof. D.V. Subba Rao, just one of over 215,000 people in India who have succumbed to Covid in the pandemic.
Prof. Subba Rao was a former Head of Department and Associate Professor at SDS Autonomous College (affiliated to Andhra University, Visakhapatnam), Garividi, India. An eminent academic he taught at the institute for more than three decades, his students admiring him for his unique teaching skill and simple explanations for different mineral and coal processing topics. 
Prof. Subba Rao published five textbooks on mineral and coal processing (Mineral Beneficiation, Minerals and Coal Process Calculations, The Belt Conveyor, Coal Processing and Utilization, Textbook of Mineral Processing) under different leading international publishers. 
He also trained many practicing engineers from different industries, including Vedanta Ltd, Essar Steel Ltd (Now ArcelorMittal/Nippon Steel), Tega Industries Ltd.  He also served as the Executive Council Member at the Indian Institute of Mineral Engineering and as President of the Indian Institute of Mineral Engineering Student Chapter, Garividi. 
Prof. Subba Rao is survived by his wife and two daughters.

Thursday, 6 May 2021

Gwennap to Carn Marth

Gwennap, a small village just 7 miles from Falmouth, gives its name to the surrounding area known as the Gwennap Parish, which in the 18th and early 19th centuries was the world's richest copper mining district, having the soubriquet 'the richest square mile on earth'.

It is estimated that there were around 3000 mine shafts in this area, relatively few being associated with the iconic Cornish Engine Houses which housed the massive pumping engines, and hoists to bring ore to the surface. The majority of these shaft were just small holes in the ground, wide enough to accommodate ladders down which the miners would descend a couple of thousand feet or more to their place of work.

It is hard to imagine what it must have been like to spend hours each day descending and ascending these ladders, but the 19th century author W. Wilkie vividly described what it was like and in 1787 the novelist William Beckford visited the Gwennap Parish and wrote "at every step one stumbles upon ladders that lead into utter darkness.... the miners who crawl out of the dark fissures are woeful creatures in tattered garments with pickaxes on their shoulders, while the mine officials regale upon beef, pudding and brandy'.

There is little evidence of this intensive mining now. Most of the mine shafts are either capped or fenced off and on a 6.75 mile walk towards Redruth, once the UK's richest town, former Elsevier journal manager Dean Eastbury and I passed only one lonely engine house, that of Pennance Consols, and the remains of granite quarrying at Carn Marth.

What was once a polluted area of smoking chimneys is now a quiet country landscape, a pleasant afternoon walk to the granite hilltop of Carn Marth, looking down on the village of Lanner, with a sweeping panorama from St. Agnes on the north coast, to Falmouth on the south. 

Our circular walk, directed by the excellent iWalk Cornwall app, began at the Gwennap Parish church, which dates back mainly to the 15th century, and took us north to Carn Marth.

Gwennap Parish church

Of historical significance on the walk is Gwennap Pit, an ampitheatre which probably originated from a mine collapse or an open-cast working. It is famous for being used by John Wesley, the founder of the Methodist movement, to preach on 17 occasions between 1776 and 1789. 

Gwennap Pit

Cornwall took to Methodism like no other county in England. For a community of miners, facing danger at work every day, and for farmers and fishermen, Wesley's simple doctrine of justification through faith and instant salvation offered comfort, security and hope. There are few towns and villages in Cornwall which do not have a Methodist Chapel.

The lone engine house which we passed was the pumping house of the Pennance mine, built in 1866. Pennance Consols, previously known as Wheal Amelia, was a small mine which produced copper, and later tin, and closed in 1874.

In 1877 there were four granite quarries on the top of the 235m high granite hill known as Carn Marth, and two of these merged to form a small lake at the top of the hill.

From the top of the hill, which looks down on Lanner and Redruth, the hills of Bodmin Moor can be seen and the hill was used as a beacon for centuries, and in Tudor times was an early warning system, where a chain of hilltop fire beacons, including the plainly visible beacon at St. Agnes, were used to warn of invasion.

Returning to Gwennap we walked through open countryside with the south coast and Falmouth visible in the distance.

More Cornish Walks
More on Cornwall
More on Cornish Mining


Monday, 3 May 2021

Biomining '21: Provisional programme now available

Biomining '21, MEI's 10th International Symposium on biomining, will be held online in June. Due to the interest shown in the conference, the number of abstracts received has allowed us to extend the event to 4 days, from June 7th-10th, and the call for abstracts remains open. 

Biomining '21 has been organised with the advice of Prof. Sue Harrison, of the University of Cape Town and Dr Chris Bryan of BRGM, France, and is sponsored by AFX Mixing & Pumping Technologies and Newmont. Media sponsors are International Mining and Industry Associates are the Cornwall Mining Alliance, the Critical Minerals Association and Ocean Mining Intel.

The provisional programme is now published, and the schedule contains sessions on:

  • Bioleaching of ores and concentrates
  • Biooxidation
  • Microorganisms
  • Secondary processing
  • Recycling
  • Environmental

with 3 keynote lectures:

How green was my biomining?; a personal critique of the limitations and untapped potential of applying bioprocessing techniques for metal extraction and recovery, by Prof. Barrie Johnson, of Bangor University, UK

Bridging gaps in biomining research and application, by Dr. Chris Bryan, of BRGM, France

Environmental applications of biotechnology in mining, by Dr. Anna Kaksonen, of CSIRO, Australia

Supplementing these presentations will be a panel discussion on the future of biomining.

There is also a virtual exhibition, which will be open throughout the conference and is a great way to showcase your company. 

Registration is now open and registered delegates will be able to view recordings of all presentations and the panel discussion on demand until December 31st.

We look forward to meeting you virtually in June.


Saturday, 1 May 2021

April update: Coronavirus; tin, the 'forgotten' critical metal; the increasing importance of the mining industry

Covid took a back seat in the news early in the month with the news of the death of the Queen's consort, Prince Philip, the Duke of Edinburgh, at the age of 99. I met him very briefly in 1980 during the Royal Visit to Camborne School of Mines, where we discussed froth flotation, which must have made him feel that his visit had not been in vain. The lasting impression at CSM was of a man with a keen sense of humour, who was very ready to put you at ease.

Globally there is little good news on the pandemic, India in particular suffering dreadfully, but here in UK there was a slow return to normality on the 12th of the month, with the reopening of shops and gyms, and pubs and restaurants allowing outdoor eating and drinking, perhaps not an appealing prospect in Falmouth, where the mid-day temperature was 8C.

First pint of the year

Very many businesses have had to adapt or die during the pandemic, and MEI has made an enormous evolutionary leap which we could not have envisaged just over a year ago.  After a void of 17 months, our first online conference, Comminution '21, was successfully held two weeks ago, and the necessary move to virtual events was made possible by the efforts of Amanda and Jon, the next generation. For the first time Jon opened a comminution conference, his recorded address being filmed and edited by Amanda's eldest son, William. I took a back seat and attended the conference as a delegate.

Jon and his nephew William record the opening address

Cornwall is gearing up for the G7 summit at Carbis Bay next month, and in March world leaders made pledges to tackle climate change, the US committing to halving its emissions within a decade and the UK enshrining in law a target of 78% cuts from 1990 levels by 2035.

Many environmental groups want these targets to be achieved earlier but the sad irony is that it is many of these who also demonstrate against mining, the very industry on which these targets are reliant on (Is Zero Carbon by 2050 Attainable?).

Copper in the past has not been regarded as a critical metal, but it should be now. It is the metal needed in increasingly large amounts to produce renewables and electric vehicles. But even now supply is barely keeping up with demand. Many large mines have a head grade of only around 0.5% copper, lower than the tailings of most mines not so long ago. Although ample copper supplies next year and in 2023 will keep the market balanced, mines need to start investing in new capacity soon to meet future demand.

Lithium supply is also critical and new sources must be found to satisfy the demand for battery production. Cornwall will help when the hard rock and brine developments at Cornish Lithium and British Lithium come on stream, but what of tin, which is ready to undergo a resurgence down here in the south west? Very little focus has been given to tin, which is one of the metals critical to achieving the projected green economy, but which has had little exposure compared with lithium, cobalt, nickel, copper and rare-earth elements.

Commonly thought of as having a major use as tin-plating in 'tin cans', plating now accounts for only 12-13% of total consumption, behind 15-18% for chemical use. The major use for tin today is in solder to create electrical connections, currently accounting for close to 50% of demand. It is this use in typically small-scale electronic components that makes the metal critical to the energy transition. Every component of the low-carbon economy requires tin, as without it electrons will not flow. While other metals can theoretically be used for this purpose, given the abundance and effectiveness of tin there really is no economic substitute.

What makes the developments in Cornwall so important is that while there is no shortage of existing and potential tin supply, that supply currently comes with environmental, social and governance (ESG) risk, as most tin production comes from countries that have high ESG risk. China, and Indonesia together account for over 50% of mine supply, while Myanmar is currently the third-largest supplier, and production in the DRC is rising quickly.

Tin might become important for another reason. Stanley Wittingham, jointly awarded the Nobel Prize for Chemistry in 2019 as one of the founding fathers of lithium-ion batteries, has recently reviewed potential for tin in lithium-ion batteries. In his paper published in October 2020 with colleague Fengxia Xin, Wittingham explains how “tin-based materials are strong candidates as the anode for the next generation of lithium-ion batteries”.

It is apparent that the mining industry is going to be vital in the coming decades and that there will be enormous challenges in supplying the critical raw materials, something which much of the world's media and environmental activists seem blissfully unaware of.


Thursday, 29 April 2021

Recent comments

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

Greta Thunberg's criticism of the Cumbrian coal project highlights her naivety
Comminution '21 provisional programme now live
Thank goodness lithium grows on trees
Gordon Ritcey: 1930-2021
February: the first steps to normality?
The Levant man-engine disaster of 1919: a contemporary account
Are these WASET conferences just a scam?
Top SME Awards to three well-known mineral processors
A final call for abstracts for Sustainable Minerals '21
In conversation with Chris Kelsey- mineral processing innovator
2020 MEI Young Person's Award to Ahmad Hassanzadeh
Tony Holland-Batt, 1937-2020
Return to Nchanga, Zambia's greatest copper mine
Memories of Comminution '01, Brisbane
Controversial "invisible gold" paper published
Two new editors and a new editorial structure for Minerals Engineering
The real cost of using neodymium in wind turbines
Why good technical English is important for journal papers
New book: Of Earth, For Earth: The meaning of a mine
Comminution '21: only 4 days away
No welcoming reception for comminution delegates this year unfortunately
Comminution '21 Day 2 update
Comminution '21 Day 4 update

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Monday, 26 April 2021

What is the future for biomining?

Biohydrometallurgy is an important technology used by the mining industry, mainly for the recovery of copper from low-grade ores and in the pre-treatment of gold-bearing refractory concentrates. 

However, despite the excitement of 40 years ago, it remains a niche technology; applied where it offers unique advantages or no alternative exists. Advances in competing hydrometallurgical processes, such as chloride leaching and HPAL mean bioleaching is at risk of losing ground. 

To halt this potential decline, and to make biomining more competitive in an increasingly busy space, serious scientific and technological advances are required, according to Dr. Chris Bryan, of BRGM, France. 

In his keynote lecture "Bridging the gaps in biomining research and application" at Biomining '21 in June, Chris will show that biohydrometallurgy is incredibly exciting, as few other technologies combine so many different disciplines. However, research is rather disparate, with relatively few resources. More than ever, as a community we need to consider how best to advance the state of the art: how to avoid the no-man’s land between academic knowledge and industrial needs and what are the key research questions. 

Chris has been a consultant for many years now on MEI's Biomining (formerly Biohydromet) conferences. Formerly a Senior Lecturer in Sustainable Mining at the Camborne School of Mines, he is now Head of the Geomicrobiology and Environmental Monitoring Unit, French Geological Survey (BRGM).

Chris Bryan (right) at Biohydromet '16 with
Shafiq Alam of University of Saskatchewan

Chris's keynote will complement that of Prof. Barrie Johnson (posting of 8th April 2021), who will give a personal critique of the limitations and untapped potential of applying bioprocessing techniques for metal extraction and recovery.

In a 3rd keynote at the conference Dr. Anna Kaksonen (posting of 12 October 2018) will show how biotechnology is set to have an increasingly important role in the quest for the circular economy, particularly in remediation, treatment of tailings, electronic and other wastes, and as a potential aid to processes such as flotation.

These three keynotes will provide the basis for the panel discussion "What is the future for biomining". The full programme for the conference will be published very soon.


Thursday, 22 April 2021

Comminution '21 Day 4 update

Thursday 22nd April

It was good to have Joe Pease, of Mineralis Consultants, Australia on Tuesday's panel discussion. Four years ago he and his colleague Bill Johnson (posting of 27 August 2020) were inducted into the International Mining Hall of Fame, for their pioneering work in bringing stirred milling into the minerals industry in the mid-1990s.

Joe Pease (left) with Bill Johnson

Stirred mills were introduced into the minerals industry for ultrafine grinding of refractory ores, but their use is now being extended into coarser size ranges, the subject of a paper this morning by Monday's keynote speaker Chris Rule.

It is difficult to overestimate the impact that stirred milling has had on comminution circuits, and the morning session contained 9 presentations on stirred mills and their associated ceramic media, from Australia, Canada, France, South Africa and UK, including two from conference sponsor Keramos, an Australian based company with over 20 years experience in the manufacture and supply of cutting edge ceramic grinding media into the mining and minerals industries.

Media for stirred mills is now a very competitive business, and apart from Keramos, there are three more dedicated suppliers exhibiting, sponsor Dakot from South Africa, and two from China, sponsor King's Beads, and Betterwear New Material, a welcome new company to the comminution series. It was interesting to browse their brochures in their booth.

The final session of the conference, on Mills and Circuits, began with a presentation by Glenn Stieper, of conference sponsor Glencore Technology, Australia. He stressed that as resources degrade towards complex ores, larger plants and throughputs are needed to achieve the same project economics, but this is in conflict with a concurrent demand for better safety, environmental, capital cost, operational cost and energy performance.

To address this conflict, mineral processing must evolve and Glencore Technology has developed a concentrator design that achieves a smaller volume of capital equipment, a lower profile and footprint, less environmental impact and greater safety. This is via the marriage of its first 5MW M20,000 IsaMills with a full circuit of new and larger throughput Jameson Cells.

Australia’s Russell Mineral Equipment, a global leader in the design, manufacture and supply of grinding mill relining technologies and services, has made massive contributions to recent comminution conferences, sponsoring and having three exhibit booths and 15 representatives at Comminution '18

This year has been no exception. The company is sponsoring once more, has a virtual booth, and 17 registered delegates, and in the final session a presentation by Stephen Gwynn-Jones on automated mill relining, which was followed by a presentation by Waldo Verster of Multotech, South Africa on mill liner optimisation.

Following a full day of presentations Jon Wills announced the result of the draw for the generous prize donated by conference sponsor Cancha. This was a 12 month subscription to Cancha Geometallurgy Software, including training and support, worth US$2,900. Cancha is an integrated geometallurgical toolkit for sample selection, 3D visualization, model generation, and data analysis and bridges the gap between geological knowledge and comminution simulators. The lucky winner was Ann-Christin Böttcher, of TU Braunschweig, Institute For Particle Technology, Germany.

Jon then brought proceedings to an end by thanking the sponsors once more, as well as all the presenters, exhibitors, and the delegates for being so active in the discussions. All that was missing was an invitation to adjourn to the Vineyard Hotel Gardens for a final drinks function, but hopefully this will happen next April at Comminution '22.

Memories of Comminution '18

Despite this being our first online conference we have been very pleased with the way that it progressed. The 67 presentations were very professional and there was a great deal of delegate interaction. These discussions can continue for a further 6 months, as the conference will remain online, and we invite further registrations at any time. At the moment there are 213 registered delegates and this number is increasing daily.

We would greatly appreciate your feedback on the event, and invite you to submit your comments and criticisms to this blog post, as your opinions will be of great value to us as we progress to future events.

Thankyou all of you for your support.


Wednesday, 21 April 2021

Comminution '21 Day 3 update

Wednesday 21st April

Day 3 of Comminution '21 was devoted entirely to High Pressure Grinding Rolls (HPGR) and SAG Mills (see footnote), and opened with a keynote lecture from John Starkey, of Starkey & Associates, Canada, who described how to get the best performance possible from your existing machines in order to keep down operating costs.

This was an excellent presentation, very clear and concise, which should be seen by everyone involved with SAG milling. John began by saying that the SAG mill is the heart and soul of many mineral processing plants and every engineer should know how to design a SAG mill.

He was critical of JK software for design, although he felt it excellent for optimisation, and it is a shame that we have no representation from JKMRC at the conference as this could have led to an interesting discussion.

Questions started to flow into the online discussion only 15 minutes into the presentation, and I must say that we have been very pleased by the interaction between delegates and presenters via the online text facility. Although there are obvious difficulties due to time zones, questions and replies to all presentations have been coming in not only during, but also well after the presentations, and discussion can go on for another 6 months, so we do ask the presenters to dip in occasionally.

Starkey & Associates are regular sponsors and exhibitors at the comminution series, and I visited their booth during the first break, which followed two innovative presentations from Australia on hybrid comminution machines and circuits, the presentation from Mike Daniels on Eccentric High Pressure Centrifugal Comminution being the subject of a recent article in International Mining

This week has been my first experience of a virtual exhibition, and I was initially sceptical, but I have found it to be very relaxing and rewarding to "stroll" around the exhibits and call in at the booths to browse the literature on display. The company representatives are clearly displayed in the booth, and if they are not actually within the booth at any one time, they can easily be contacted via the meeting hub. The only drawback of a virtual booth, of course, is that there is no working equipment to view.

After the 6 morning presentations on HPGR, the afternoon session contained 11 presentations on SAG milling, including another presentation by John Starkey, and one from another conference sponsor ME Elecmetal, USA, Amit Saxena describing the optimisation of discharge flow efficiency in a SAG Mill.

Another great day ends, and we look forward to tomorrow's sessions on Stirred Mills and Milling Circuits.


By clicking on any presentation in the programme, you will be able to see the abstract and the biographical details of the presenter. All presentations will be available for 6 months, so you can register for the event at any time.

Tuesday, 20 April 2021

Comminution '21 Day 2 update

Tuesday 20th April

What novel machines are to be found in the future? In the first presentation of the day, Dr. Paul Cleary, of Australia's CSIRO, described in his keynote lecture the Virtual Communition Machine, an approach which is already being used to drive the rapid evolution of comminution machine design. The presentation contained truly amazing animations of simulated comminution in various machines, which allow new ideas to be trialled in a virtual framework at a fraction of traditional cost and time. The VCM can provide much greater mechanistic insight, which can improve and accelerate development of new machines, as well as machine scale-up.

Paul at Comminution '18 with Mintek's Elizma Ford,
who will be presenting a paper on Thursday

Paul's keynote was the first paper in Modelling and Simulation, the theme of today's long technical session (see footnote). Progress in computational methods have come on at a tremendous pace in the last half century so it was a privilege to have one of the early pioneers of mathematical modelling in mineral processing, Prof. T.C. Rao with us at the conference. Prof. Rao obtained his Ph.D degree under the guidance of the JKMRC's first Director, Prof. Alban Lynch, in 1965, working on the characteristics of hydrocyclones. They published their work on hydrocyclones in a number of seminal papers, and the models are still valid today, being used in many hydrocyclone manufacturers' performance curves. 

Profs. Rao and Lynch reunited in Brisbane in 2016

Prof Lynch, who is now 91, intended to be with us today, but unfortunately was unable to do so but sent his best wishes to all at the conference. The last time Alban Lynch and Paul Cleary met at an MEI Conference was 20 years ago, at Comminution '01, and I'm sure that both Alban and TC would have loved to have spent time with Paul at this year's event, as Paul is also a pioneer of a technique which they would not have heard of in the early 1970s, but was introduced to us all at Comminution '01- DEM Modelling, the subject of a number of papers today. And they would certainly not have heard of Positron Emission Particle Tracking (PEPT) which has become a widely used tool in recent years, and two presentations from South Africa showed how PEPT has been used to validate DEM Models for tumbling mills and stirred mills.

"What will comminution circuits look like in 2050?" was the theme of the mid-day panel discussion, chaired by Mike Battersby of Maelgwyn Mineral Services Ltd, UK, and Chairman of CEEC. Giving their views were Grant Ballantyne (Australia), Joe Pease (Australia), Alex Potapov (USA), Peter Radziszewski (Canada), Paul Shelley (Australia) and Weigo Xie (USA).

There was a wide ranging discussion, but a general consensus was that coarse rejection of gangue prior to comminution, and separation at as coarse a size as possible, concomitant with recovery, would be needed to reduce energy and water consumption. It was also felt that there would be more emphasis on dry grinding and processing, although there are environmental and health concerns associated with this. Alternative technologies such as high voltage fragmentation and microwave heating, to weaken grain boundaries, might also be used but although good work at small scale has been carried out they may not be able to be fully utilised at high throughputs.

Secondary mining and processing was also touched on, and Grant Ballantyne felt that there would be much more emphasis on processing old tailings in the future, with reduced comminution requirements.

Not surprisingly there was much discussion on simulation and the use of artificial intelligence and Mike Battersby commented on Paul Cleary's keynote this morning, endorsing my opinion of the superb simulations showing how far we have come over the last couple of decades.

Grinding is evolving and changing fast, with innovations in high pressure grinding rolls and stirred mills threatening to make the tumbling mill, which has been a stalwart for well over a century, obsolete. At the panel discussion at Comminution '14 Tim Napier-Munn said that in terms of the future of comminution "we really have to get rid of tumbling mills". Are rod mills now finally obsolete? Ball mills would have dominated comminution conferences little over a decade ago, but they are mentioned only rarely now.

This question came up at the very end of today's panel discussion, and I would have liked to have heard more from the panel, who felt that tumbling mills would still play a role, but that they would be more efficient, particularly regarding the associated classification.

SAG mills are still of major importance, but I asked the question at Comminution ’12 whether ball mills would play a significant role in comminution circuits, or would they be superseded by SAG mills. Chris Rule, yesterday's keynote speaker, felt at that time that rod mills would play an insignificant role, as they are severely limited in terms of size, and ball mills may play a diminishing role as the upper feed size range of stirred mills increases. 

With HPGR grinding finer and stirred mills taking coarser feeds this is open to discussion, and we will no doubt hear more of this in the next couple of days, tomorrows sessions covering HPGR and SAG Mills, and Thursday Stirred Mills and Grinding Circuits.


By clicking on any presentation in the programme, you will be able to see the abstract and the biographical details of the presenter. All presentations will be available for 6 months, so you can register for the event at any time.

Monday, 19 April 2021

Comminution '21 Day 1 update

Monday April 19th

Although we had planned to be in Cape Town today, I am greatly looking forward to the next few days, attending MEI's first online conference solely as a delegate. Perhaps fortuitous that we are online as it is 35C in Cape Town at the moment and our thoughts are with Capetonians, and our five delegates from the University of Cape Town (UCT) as their University campus was engulfed yesterday by a raging bushfire on Table Mountain, which jumped the major M3 road between the mountain and the Vineyard Hotel, destroying the 200 year old Moster's Mill, the windmill being a familiar landmark for conference delegates travelling to the conference venue from the airport. UCT's historic library and other buildings have also been badly affected by the fire.

The last 12 months have seen the evolution of conferences into virtual and hybrid events and we’ve chosen the EventsAIR platform for our conferences as we feel that it provides delegates with the most opportunity to connect, which those who have attended one of our events in the past will know is an important feature of an MEI conference.

Despite the difficult circumstances we have a fine technical programme over the next four days, with around 65 presentations from authors from 22 countries, including 3 high profile keynote lectures.  As it is three years since our last comminution conference, Comminution '18, we expect to see and hear of many innovations as comminution continues to evolve.

Comminution '21 is MEI's 12th Comminution conference, and the first at which I have not delivered the welcoming address. That privilege has now passed on to the next generation, and it was Jon Wills who opened the conference this morning, welcoming over 200 delegates from 24 countries and thanking our sponsors, who have supported us all the way as we have had to adapt to this new reality. Without their continued support we would not be here today meeting together online.

Jon opening the conference from Cornwall

Jon highlighted that comminution is one of the most energy intensive operations in mining. Research generally shows that it accounts for around 30-50% of a mine’s overall energy consumption, and in his keynote presentation at Comminution ‘14, Tim Napier-Munn informed us that it accounts for 1.8% of global energy consumption.

This is a shocking amount of energy to be using, and although there are now moves by the industry to use more renewable energy sources, which results in a reduction in greenhouse gas emissions and increased sustainability, the drive to bring this figure down continues in an effort to reduce operating costs.  

It was appropriate therefore that the first morning was devoted to energy and breakage (see footnote), with Chris Rule, of Seymet, South Africa, starting proceedings by asking in his keynote whether mineral processing operations can make significant energy savings by adopting new technologies and challenging conventional flowsheets?  

Chris Rule at Comminution '18 with his daughter Jessica,
and Brian Chaponda of Lonmin
Chris's keynote was followed by eight papers from Australia, Canada, Germany, Namibia and UK, ending with a presentation related to the question posed in the keynote, Xinyi Tan, of the University of Toronto, asking whether energy savings can really be made by microwave assisted comminution.
During the 40 minute lunch break we had our first speed-networking session, where delegates had the option of being placed at random into a group of maximum 4 participants for 5 minutes, after which we were moved to another group, our way of recreating those random meets over a cup of coffee at a conference!

This I felt was a surprising success, due to its random placement of participants- at an old-fashioned conference groups don't normally meet at random, as people tend to gravitate towards those that they already know. This virtual networking break allowed us to take notes on new potential contacts with the option of scheduling a more formal meeting later via the meeting hub.
I hope more people will join in to the networking session tomorrow as it is a valuable way of "breaking the ice" and building new contacts.
Seven presentations on Control and Instrumentation formed the afternoon session, the last being by CiDRA Minerals Processing, who regularly exhibit at MEI's comminution and flotation events. This year they are one of the 21 virtual exhibitors and I really would like feedback on what exhibitors and delegates think of virtual exhibiting, as it is obviously much different to what we have been used to.
I think a good day in general, and look forward to being back tomorrow
By clicking on any presentation in the programme, you will be able to see the abstract and the biographical details of the presenter. All presentations will be available for 6 months, so you can register for the event at any time.

Sunday, 18 April 2021

No welcoming reception for comminution delegates this year unfortunately

April 18th and this afternoon we should have been welcoming our delegates to the Vineyard Hotel in Cape Town for Comminution '21.

Welcoming reception at Comminution '18

Covid put paid to that unfortunately but we are not downcast as tomorrow begins our new adventure, MEI's first totally online event.

There is much to look forward to, particularity the novel networking sessions, which I shall report on tomorrow.

We have over 200 delegates from 22 countries already registered, and it is certainly not too late to register, as all presentations, and the panel discussion, will be available on demand for delegates for 6 months after the event.

I will be publishing brief updates daily on the blog and if you are attending the conference we would very much appreciate your comments, which will be of great value to us as we step onto the steep learning curve. If you are active on Twitter we also look forward to regular tweets, and I would be grateful if you could use the hashtag #Comminution21.

See you tomorrow!

Thursday, 15 April 2021

Comminution '21: only 4 days away

Comminution '21 is MEI's first online conference, and I must admit to being excited about attending the 4-day meeting solely as a delegate, joining the many other delegates from around the world. Although tinged with a little sadness, as tonight we should have been boarding a plane to whisk us to Cape Town and the Vineyard Hotel.

Amanda and Jon have put the bulk of the effort into organising this virtual event, our 12th Comminution conference, and the first at which I will not be opening the proceedings. Jon will welcome delegates at 09.00 BST on Monday, the start of four days of over 65 presentations, including three state-of-the-art keynotes.

"What will comminution circuits look like in 2050?" will be the theme of the panel discussion on Tuesday, chaired by Mike Battersby of Maelgwyn Mineral Services Ltd, UK, and Chairman of CEEC. Answering questions will be Grant Ballantyne (Australia), Joe Pease (Australia), Alex Potapov (USA), Peter Radziszewski (Canada), Paul Shelley (Australia) and Weigo Xie (USA).
Although networking at a virtual conference will never replace face to face interaction, as we would be enjoying in the Vineyard gardens, there is a lot to look forward to next week in the comfort of your home or office. There will be plenty of opportunity to visit the virtual exhibition booths and interact with the exhibitors, and we will be introducing a novel way of simulating the chance encounters which happen at every conference and which can often lead to valuable contacts.

We invite you to register for Comminution '21 and take the opportunity of exploring the OnAIR platform before Monday. The timetable will be rigidly adhered to, so you can easily set your own agenda, and if you miss a presentation you can always catch up later, as all presentations will be available on demand for 6 months. You can even join the discussions on presentations well after the event, via the online chat facility.

So we look forward to your active involvement in "the cloud" next week and I look forward to 'bumping' into many of you during the virtual coffee breaks. A final thanks to our sponsors who have supported us all the way.


Monday, 12 April 2021

New book: Of Earth, For Earth: The meaning of a mine

Of Earth, For Earth is a 116-page full-colour, hardcover book, consisting of dialogue between artists, community representatives, industrialists and educators.  It aims to inspire debate about human interactions with the Earth, while our consumption of resources grows ever larger and the environments on which we depend face an uncertain future.

The book is edited by Kathryn Moore, Dana Finch and Bridget Storrie, and is part of the dissemination strategy of the IMP@CT project, led by a science and engineering team at the Camborne School of Mines on the Cornwall campus of the University of Exeter, to build security into raw materials supply through mining. The European Union H2020 science and innovation programme funded the IMP@CT project under Societal Challenge 5: climate action, environment, resource efficiency and raw materials.

The book arises from a unique interaction between artists and the mining world. The contributors intend to open conversations about our consumption of the Earth’s resources, recognising the inter-related and manifold issues. It highlights the dependence of society on mining to supply raw materials for the technologies that will combat climate change. It provides a space for all viewpoints, in the hope that through dialogue we can find solutions that are truly responsible and practicable. 

Thursday, 8 April 2021

How green is bioprocessing?

The modern era of biomining began in the 1960s, with low-tech “dump leaching” used to recover copper from what had been considered to be waste (run-of-mine) rock. “Biomining” has since evolved into a variety of more complex engineered practices, including bioheap leaching and stirred tank operations. 

Protagonists, and particularly researchers justifying support from industry and research councils, have often promulgated the notion that bio-processing is a much “greener” method of winning metals than conventional (e.g. pyrometallurgy and pressure leaching) approaches. But according to Prof. Barrie Johnson, of Bangor University, UK, such claims do not always stand up to close scrutiny. 

In his forthcoming keynote lecture “How green was my biomining?”; a personal critique of the of the limitations and untapped potential of applying bioprocessing techniques for metal extraction and recovery", at Biomining '21 in June, Barrie will give a critical overview of the environmental impact of biotechnologies in mineral processing and metal recovery, identifying areas where existing approaches have (and do not have) significant green credentials, and will also highlight where new developments, currently at the laboratory or pilot-scale stage of development, could have major environmental impact in future years.

Barrie Johnson with Bangor University colleagues at Biohydromet '16 in Falmouth

Biomining '21 will be MEI's 10th International Symposium on Biomining,the postponed Biomining '20, which was scheduled to be held in Falmouth.


Monday, 5 April 2021

Comminution '21: only two weeks away, and two new sponsors

MEI's first online conference begins two weeks today. Comminution '21 is our 12th comminution conference, and I must say that I am excited about attending as a delegate, along with the other delegates, while Jon and Amanda do the hard work of ensuring that the proceedings move smoothly.

We also welcome two late sponsors, Dakot and Cancha, who join our existing sponsors and we look forward to networking with them during the event.

South African company Dakot are sponsoring an MEI comminution conference for the 3rd time. 

Dakot was established in 1995 to manufacture high-tech ceramics for specialised applications. In 2007 it diversified into the production of ceramic micro-milling media. The company has positioned itself as one of the world leaders in the large scale production of toughened alumina and zirconia grinding media for stirred mills, which will be featured in the final morning session of the conference.

Cobus Kotze (2nd left) of Dakot, with Aubrey Mainza and Paul Bepswa, of UCT,
and Magnus Evertsson of Chalmers University, at Comminution '18

Peruvian company Cancha is a first time MEI sponsor. Cancha is used by geologists, miners, metallurgists and geometallurgists to accurately, efficiently and transparently project metallurgical performance for mineral resources, the geometallurgy software bridging the gap between orebody knowledge and comminution simulators. 

Cancha's Transmin offers professional metallurgical consulting services to the mining and mineral exploration industries and I first met consultant Adam Johnston at the SME Annual Meeting in Denver in 2019. 

With Adam Johnston, and Stuart Smith of Metifex, Australia in Denver in 2019

Adam says that he is "happy to be able to support this conference.  For many years we have enjoyed reading the papers from the Comminution conferences in Minerals Engineering, but travel and time has always been a barrier to get there in person.  Now with it being online, and us being locked-up, we are able to get involved".

It is good to have these two late sponsors involved, and I hope that others, who have been unable to travel to our conferences for whatever reason, will avail themselves of the opportunity of registering and networking with comminution experts from around the world, in the comfort of their own homes or offices.


Thursday, 1 April 2021

March update: Coronavirus, University rankings, UK mining news and a levitating ship in Falmouth Bay

Champagne corks were flying throughout the land on the 8th of the month, as many parents, Amanda and Jon included, celebrated the return of their children to school. The nation is still effectively in lockdown, but the tide seems to be turning in the UK and restrictions were eased on the 29th. However, with a resurgence of infections in Europe, Boris Johnson warned that the effects of a third wave of Coronavirus in Europe will "wash up on our shores" and that we should be under no illusion that the country will feel the effect of increasing European cases. March 23rd was the first anniversary of the initial lockdown, and since then the UK's official death toll rose from 364 to 126,172 twelve months later.

The roll out of the Coronavirus vaccines has been impressive to say the least. At the end of the month  31 million people in UK had received their first jabs and over 4 million their second. The NHS must once again be highly commended for this. Front line workers have put their lives on the line throughout the pandemic and over 150 nurses died, so it was not surprising that there was an inevitable backlash to the Government's offer of a 1% pay rise, presumably to supplement the appreciation received by clapping during the early months of lockdown, and ministers saying that their gratitude was incalculable.

Chancellor Rishi Sunak and PM Boris Johnson
clap for front-line health workers outside No. 10

This meagre offer coincided with a report from the House of Commons Public Accounts Committee showing that there was no clear evidence that the "unimaginable" budget of £37 billion for the NHS Test and Trace system had been justified and had made no measurable difference to the progress of the pandemic. In early February it was still employing around 2500 consultants at an average daily rate of £1000 with some paid £6624 per day, putting the pay rise to nurses, of around £3.50 per week, into perspective.

In other news the 2021 QS World University Rankings were published last month, and in the field of Minerals & Mining Engineering, the Camborne School of Mines had its highest ranking ever, number 8 in the world (as University of Exeter).  All the more ironic as in January, following 5 months of deliberations, Exeter University decided to continue the ‘pause’ in offering the Mining Engineering undergraduate degree programme, effectively bringing an end to CSM's proud record of training graduate mining engineers, which has its origins back to 1888, and all at a time when there is a resurgence in mining activity in Cornwall.

Cornwall has always been regarded as the birthplace of modern mining, once being the world's largest producer of copper and tin. Now of course there is also lithium, and there was good news last month that British Lithium Ltd has been awarded a grant of almost £3m by the government’s Sustainable Innovation Fund, which will allow the company to progress its plans for a pilot plant to prove the sustainability and commercial benefits of its Li-Sep technology for extracting battery-grade lithium from micaceous granite in east Cornwall. 

Progress also continues in bringing one of the county's oldest tin mines into production again. In 1998 South Crofty was the last of Cornwall's tin mines to close, and its redevelopment by Cornish Metals involves the formidable task of dewatering the miles of ancient underground workings. Extensive pilot-scale water treatment trials have been carried out and the company has successfully applied for and received the necessary environmental permits to abstract, treat and discharge mine water in order to dewater the mine.

There was good news in March that an agreement had been reached with Wheal Jane Ltd for the disposal of waste material derived from the treatment of mine water from South Crofty into the Wheal Jane tailings dam located 12 kilometres east of South Crofty at Baldhu near Truro.  In addition to that the company has also made a deal to lease a 1.2 hectare site surrounding New Roskear Shaft in Camborne for up to 23 years, together with an agreement to lease the mineral rights owned by Roskear Minerals LLP within the South Crofty Underground Permission Area for up to 25 years. 

In 1920, when further exploration of the bottom levels of Dolcoath Mine (posting of 3rd August 2015) became unprofitable, the mine was abandoned and attention was directed to the Roskear section to the north and in 1926, New Roskear, a 650 metre deep, six metre diameter shaft in the centre of Camborne was sunk to a depth of 2,000 feet between the North and South Roskear main lodes, in order to explore the ground below the copper ore zone of these mines where rich tin ores were believed to exist. During the 1980s and 1990s, much of the ore mined from South Crofty came from this part of the mine, and the new agreement secures access to the shaft, which is important for ventilation and access to South Crofty.

The capped New Roskear shaft

Not so good news in the north-west of England, however, where a public inquiry has been announced into plans for the Cumbria coal mine (posting of 14 January) after another of the government's famous U-turns. Green campaigners say the mine will increase carbon emissions and send the wrong signal in the run-up to a UK-hosted climate conference in October. Asked whether the government now backed the mine or not, Boris Johnson said he couldn't get involved as it was now a "qausi-judicial planning decision" (a shame he didn't read my posting on clear technical English).

The Conservative MP for nearby Workington, Mark Jenkinson, called the decision a "capitulation to climate alarmists". He said the "screeching U-turn" could open a "Pandora's box" over how the UK's contribution to climate change is measured, adding there was "nothing on the horizon" to replace coking coal in the process for making steel, a sector that is due to play an important role in the UK's "green recovery".  As I said in my posting of 14 January, it may seem paradoxical, but mining of coal is essential in the quest for a zero-carbon society. Metallurgical coal, which would be mined in Cumbria, is required to produce steel, but it is rarely appreciated that fossil fuels, whether from coal or gas, will also be needed for some time yet, in order to help build the electric vehicles and wind turbines of the future. There just aren't enough renewable sources of energy at present to provide the energy to mine and extract the necessary raw materials and to manufacture the multitude of renewable energy devices and electric vehicles which are proposed.

The government could still decide to approve the mine, but given the amount of anger it's caused, that seems unlikely - at least until after the UN climate conference.

And finally, on a lighter note, earlier in the month, a hovering ship was seen off the Falmouth coast, the result of a rare optical illusion known as a "superior mirage" where special atmospheric conditions bend light. Superior mirages occur because of a temperature inversion, where cold air lies close to the sea with warmer air above it. Since cold air is denser than warm air, it bends light towards the eyes of someone standing on the ground or on the coast, changing how a distant object appears, the opposite of an "inferior mirage" where the light is bent the other way, and the mirage image appears below the true object, as in desert mirages.


Sunday, 28 March 2021

Final calls for abstracts for Biomining '21 and Sustainable Minerals '21

A final reminder that if you would like to present papers at Biomining '21 and Sustainable Minerals '21 in June, abstracts should be submitted by the end of this week.

These are the conferences originally scheduled to be held in Falmouth, and more details can be found on the blog postings of 11th March (Biomining '21) and 4th March (Sustainable Minerals '21).