A welcome to Computational Modelling '15 delegates

Good to see so many familiar faces, and some new ones, at this afternoon's welcoming cheese and wine reception at the St. Michael's Hotel. Hopefully the delegates will now be taking advantage of the glorious evening sunshine, and sampling the delights of Falmouth.

 

Beautiful Falmouth awaits our international audience

Falmouth is looking glorious at the moment, warm and sunny, so we look forward to welcoming around 90 international delegates for this week's two MEI Conferences.



This evening is the welcoming wine function for Computational Modelling '15, the 2-day conference beginning tomorrow. This will be followed by Physical Separation '15 on Thursday, and I am hoping that the weather will hold for the tour around the Camborne-Redruth copper and tin mining district on Friday afternoon.

As always, there will be daily updates on proceedings on Twitter (@barrywills) and on the blog.

Direct leaching of PGM ores and concentrates

Jacques Eksteen

Last month's Precious Metals '15 conference got off to a fine start with a keynote lecture, given by Jacques Eksteen of Curtin University, Australia, who reviewed recent innovations in the processing of difficult and low grade gold ores, and we look forward to seeing this paper published in the special issue of Minerals Engineering.

Jacques and his co-workers at Curtin University have another excellent paper on precious metals processing, this time platinum group metals (PGMs), in Volume 78, the latest issue of Minerals Engineering. PGMs, often with associated gold, have very few occurrences where they are present in an ore deposit at economically extractable levels. They are classified as both precious and critical metals due to their scarcity and their wide industrial use. With deteriorating socio-political environments in most primary PGM producing countries, PGM deposits that are smaller but in less risky jurisdictions have to be evaluated. However, the lower PGM grades, increased mineralogical complexity of the ores, capital intensity and strict environmental regulations in other international jurisdictions, limit the implementation of conventional metallurgical processing options, particularly smelter-based operations. The conventional smelter-based process options are justifiable for high grade, low chromite, large resource and long life-of-mine operations.

In the present paper, Eksteen and his co-authors review some of the most recent literature on the predominantly hydrometallurgical approaches to PGM extraction. A number of metallurgical processes that generate either a PGM rich leachate or a residue containing metal values, and the various methods in use for their recoveries from pregnant rich solutions are reviewed. Sixteen process flowsheet variants combining conventional and proprietary unit process technologies are provided, and their process chemistries and key technical operating parameters are compared. Where appropriate, the key thermodynamic and kinetic factors are given and compared.

Another eminent keynote speaker for Flotation '15

We are pleased to announce that we have already received a record number of abstracts for Flotation '15 in Cape Town in November, and that 22 exhibition booths have been reserved, leaving only two available at the moment.

We are also delighted to welcome Dr. Janusz Laskowski who will deliver a keynote lecture Anisotropic surface-property minerals in flotation circuits.

Dr. Laskowski, Professor Emeritus of mineral processing at the University of British Columbia, Canada, obtained all his degrees, including Ph.D., from the Silesian University of Technology in Poland. His education also included one year stay as a postgraduate student with Department of Colloid Chemistry, Lomonosov University, Moscow, and one year stay as a post- doctoral fellow with Dr. J.A. Kitchener at Imperial College, London.

In 1979, he chaired the 13th Int. Mineral Processing Congress in Warsaw. In 2002 he started his own research company, Laskowski Research Inc.

Dr. Laskowski was awarded the Lifetime Achievement Award of the International Mineral Processing Council at the 24th International Mineral Processing Congress in Beijing (2008), and is a recipient of the Antoine Gaudin Award (2011).

I would also like to thank all our sponsors, also a record number, for their support of what is likely to be MEI's biggest conference to date.

 

In memory of Richard Mozley and his wonderful machines

Physical Separation '15 starts one week today in Falmouth. This is the 4th of MEI's Physical Separation conferences, but not the first on this theme to be held in Falmouth. Eighteen years ago this month the Institution of Mining and Metallurgy hosted Innovation in Physical Separation Technologies, a memorial symposium in remembrance of Falmouth minerals engineer Richard Mozley.

Richard Mozley and Roger Parker, 1986

Richard had died two years previously, and on the second morning of Minerals Engineering '95 (posting of 28th May) I had the sad duty of announcing his death to the international audience, and a few days later acting as a pall-bearer at his funeral in the little church at Carbis Bay, close to the beautiful cliff-top golf course where Richard would play regular golf with his friend Roger Parker, Vice-Principal at CSM.

In his keynote lecture at the symposium, the Director of Australia's JKMRC, Tim Napier-Munn, spoke of invention and innovation in mineral processing, appropriately as Richard Mozley was a great inventor and innovator, in the mould of other illustrious engineers in Cornwall, notably Sir Humphry Davy and Richard Trevithick (posting of 25th April).

Richard Henry Mozley MBE was not, however, a Cornishman. He was born in Sussex in 1933, and studied mining engineering at the Camborne School of Mines in the 1950s. During his time there he undertook a final year project with the then head of engineering, Dr. G.H. Jones, who was working on a prototype wet high intensity separator, which evolved into the well-known Jones Separator. This must have ignited Richard's passion for R&D work as he then spent 2 years at the University of Bristol, working on spiral related gravity concentration, leading to the development of the Shaken Helicoid, an orbital concentrator for the recovery of fine tin particles, which was subsequently licensed to the Cornish company Bartles (Carn Brea) Ltd, who went on to sell over 200 units.

A brief spell as a mining engineer with the Indian Copper Corporation, and in 1961 at the Amalgamated Tin Mines in Nigeria, convinced Richard that his future career lay in mineral processing, and he took a position at the Warren Spring Laboratory in Hertfordshire, where he was involved in the development of gravity devices, before returing to Bristol University as a Research Fellow. It was here that his interest in developing gravity concentrators to treat ultrafine cassiterite in the Cornish tin mines took over and he developed a modern separator to replace the round frames and vanners traditionally used in Cornwall. The result was the first machine to bear his name, the Mozley Table, developed further by Bartles and marketed as the Bartles-Mozley Concentrator, initially installed in the Geevor tin mine, and then in many concentrators around the world. As this was essentially a roughing or scavenging device, Richard went on to develop the Bartles Cross-Belt Separator to upgrade concentrates from the B-M Concentrator. Again this was commissioned at Geevor but was soon taken up on several chromite installations in the Philippines and Europe.

After meeting and marrying a local girl, Abigail, Richard settled in Cornwall and took up residence in Falmouth. He joined nearby Hydraulic Tin as a mineral processing engineer in 1971 and became General Manager and Director, but in 1975 he decided to go it alone as an independent consultant, concentrating on inventing and developing processes for recovery of fine heavy minerals. He initially worked from home, and it was always a treat to visit his large house in Wood Lane, Falmouth, and to see Abigail in the kitchen surrounded by centrifugal pumps, pipes and prototype hydrocyclones and other machines. He soon set up Richard Mozley Ltd and in 1986 he and his technical staff moved from Falmouth to new premises in Redruth.

The company initially concentrated on the development of small hydrocyclones for desliming feeds to gravity concentrators, and the sand separator, a development of the conventional shaking table, which was tested at the South Crofty tin mine. This was eventually licensed to GEC Mechanical Handling as the Duplex Concentrator, although Richard Mozley Ltd developed a small laboratory version, the laboratory mineral separator, which I used extensively for testwork at CSM, as did several hundreds of institutions and mine laboratories around the world. The Mozley cyclones also became world famous, particularly the 1 inch and 2 inch diameter plastic hydrocyclones assembled in a high-capacity housing.

I particularly remember Richard talking enthusiastically, over a few beers, about his latest invention, a shaking table wrapped through 360 degrees into a circular drum which was not only shaken, but rotated to produce a high-G force - one of the first of the enhanced gravity concentrators, which competed with the Knelson and Falcon concentrators. To develop this he recruited a bright experienced minerals engineer, Billy Chan, and the Mozley Multi Gravity Separator (MGS) was tested at the Wheal Jane mine, under the supervision of concentrator superintendent Mike Hallewell, and then showcased at the 1988 IMPC in Stockholm. The device has been used successfully around the world for the recovery of ultrafine heavy minerals, and soon made the B-M and Duplex Concentrators redundant.

Stockholm, 1988. Billy Chan demonstrates the MGS, with Sales Manager Don Hepburn and Richard Mozley

At the IMPC in Dresden, 1991, with Richard and his PA Joan Brookes

After Richard's untimely death in June 1995, the company struggled on until it was taken over by Axsia in 2000 and became Axsia-Mozley. When Axsia was taken over a few years later by oil and gas company NATCO it looked like the death-knell for Richard's inventions, but his loyal Executive Director Paul Salter stepped in and Salter Cyclones, based in Cheltenham now proudly carries on the Mozley tradition, concentrating on manufacture and sales of the original Mozley cyclones and of course the MGS, the most recent installation of the 5 tph unit being in Finland at Outokumpu's Kemi chromite mine.

The 5 tph MGS

Richard was a larger than life character who is still sorely missed. I am sure many of you have memories of him, and I invite you to share them. I would also be interested to know if any of his early machines, the B-M Concentrator, the Cross-Belt Separator and the Duplex Concentrator are still in use anywhere in the world. And does anyone know the whereabouts of Billy Chan?

Bridging the gap between science and engineering

Of all the changes that have taken place in mineral processing during the last 20 years or so, ranking very highly must be the development of powerful and sophisticated models for simulation, control and optimisation of operations. It has been apparent, however, that many operators have been wary of many of these developments, viewing them as clever academic exercises with no real practical value beyond the experienced operators' hands-on approach to optimisation and control. This has inhibited the development, validation and implementation of some potentially very useful techniques.

Bridging the gap between academic science and practical engineering is a problem which needs to be addressed, by bringing together academics and operators, the conference circuits being the obvious forums. We try to do this at MEI Conferences, but still we get the criticism that operators are not there in force, and the perception often is that academics are talking to academics.

There is a lot to be gained by operators attending major conferences. After attending Comminution '14 Clifford Mutevhe, of Anglo Platinum, Zimbabwe commented "[Comminution '14] not only enhanced my knowledge but also helped me identify solutions to the milling circuit I manage. Some of the discussions we had, we have carried them forward as part of the business process improvements. I also managed to identify with a huge pool of knowledgeable people from across the world. I could not imagine communicating daily and interacting with people from SA, USA, France, Iran, China, Australia and various other countries."

But we realise that we need to do more to bring scientists and engineers together, and hence bridge that gap, and we would like to see operators presenting case studies on their operations, particularly relating their experiences in utilising modern sophisticated models and techniques. At next year's Comminution '16 we are hoping to attract interest in a potential session devoted to short presentations from operators, describing how innovative techniques have benefited their circuits.

At Flotation '15 in November Prof. Jan Cilliers, of Imperial College, UK will ask in his keynote lecture "what have models and measurements ever done for us?" and will show how advances in theory and experiment take some time to move from the laboratory to the literature and on to the plant.  Immediately prior to the conference, Dr. Stephen Gay will be running a 3-day Simulation Course covering all aspects from basic data accumulation and analysis to advanced software development. Stephen will show how simulation can be used for plant optimisation, plant trouble shooting, feasibility studies and plant design. Importantly the course will give plant managers an approach by which they can obtain guidance on how to improve plant performance via reduced energy costs, and better recovery.

Immediately prior to Comminution '16, two half-day workshops will attempt to bridge the science-engineering gap. In the first of these the Coalition for Eco-Efficient Comminution (CEEC) has invited one of the conference keynote speakers, and a Director of CEEC, Joe Pease, to review the practices available to improve processing efficiency, from mining operations through to mineral processing and smelting.  Attendees will become familiar with the CEEC energy curve and how to assess their own performance.  Procedures to compare energy productivity against other operations and to track the impact of improvements using the CEEC energy curve will be discussed. Examples of practices to improve efficiency will be discussed, along with techniques to find the improvement potential at your site.  Joe will elaborate on this in his conference keynote lecture, showing how the search to improve comminution efficiency will undoubtedly include some novel new technologies.  Significant benefits are also likely from evolving existing technologies, new ways of operating, and combining the old with the new.   He will ask whether advances in drilling, blasting, crushing, HPGRs and stirred milling could relegate the SAG mill to a curiosity during our careers?

Rob McIvor, of Metcom Technologies, USA will present a keynote at the conference aimed squarely at operating metallurgists and company management. He will show how the successful development of new comminution science into real business practice is well exemplified by inventions such as high-pressure grinding. But beyond new plants and capital expansions, how is the science helping industry make the best use of the equipment at their immediate disposal? Plant operations present numerous rewards and challenges to the people who run them. Among their many tasks, metallurgical staff are responsible for the processing performance of the grinding circuits, both daily production and continuous improvement. Means to identify viable process improvement opportunities, and to engage management when needed to achieve implementation, are needed. These include the use of meaningful technical terminology, appropriate metrics, clear economic analysis, and means for follow-up validation that improvements were achieved. Rob will present practical tools for plant staff and company management to bridge the gap between grinding science and daily plant practice, demonstrated by numerous case studies.

Rob will also present the second of the pre-conference workshops, on the Sunday afternoon prior to the conference welcoming reception. The “Functional Performance Equation for Ball Milling” was first introduced in 1988, and now has been applied in scores of mineral processing plants to improve ball milling circuit performance. This powerful, yet simple, tool provides a new level of understanding of closed circuit grinding, whereby plant metallurgical staff and equipment/material suppliers can manage and improve the processing performance of ball milling circuits with clarity and confidence. This workshop is certified by The Engineering Institute of Canada, which provides each participant with a certificate of course completion and registration of 0.3 CEU’s into their training database. It is intended for plant metallurgical staff and management, grinding circuit equipment and material suppliers, and others interested in industrial circuit design and optimisation including circuit designers and researchers. 

A 3rd conference keynote will be given by Prof. Malcolm Powell, of Australia's JKMRC, one of the world's leading experts on comminition modelling. He specialises in mill liner design, charge motion and DEM modelling, SAG mill modelling, and classification, with a strong link into applying the research knowledge in extensive site work and consulting to industry, aiming to link fundamental research into applied outputs through the development of practical and robust process models. He will discuss comminution modelling in the context of integrated process prediction.

 

So this is what we are trying to do, but what are your views- what more can we do to bridge the gap between science and engineering?