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 at Comminution '23.

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.

@barrywills

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.

@barrywills

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.

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.

@barrywills

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.

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

@barrywills

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.