Are these WASET conferences just a scam?

A few days ago I received an email inviting me to submit an abstract and attend ICMEMT 2013 : the XXXIVth International Conference on Mining Engineering and Metallurgical Technology in Venice in August.

Venice in August sounded attractive but it aroused my suspicions. Would we organise an MEI Conference in Venice at the height of the tourist season when hotel accommodation is hard to find, and what is available is extremely expensive? Very strange! Even stranger when a few hours later I received another email, inviting me to submit an abstract and attend the XXXIVth International Conference on Mining Engineering and Metallurgical Technology in Prague in July!!

The conference(s) apparently aims to bring together leading academic scientists, researchers and scholars to exchange and share their experiences and research results on all aspects of Mining Engineering and Metallurgical Technology, and discuss the practical challenges encountered and the solutions adopted. Apparently this is “the premier forum for the presentation of new advances and research results in the fields of Mining, Mineral Processing and Metallurgical Engineering”. Really? So why, especially if it is the XXXIVth in the series, have I never heard of it? My next step was to look at the conference website.

Papers from the conference will apparently be published in a special issue of World Academy of Science, Engineering and Technology (WASET) “a scholarly open access, peer-reviewed, interdisciplinary, monthly and fully refereed journal focusing on theories, methods and applications in Science, Engineering and Technology. WASET offers a single, highly recognized platform where peer-reviewed high quality scientific papers can be hosted and accessed by millions of researchers, enabling authors to keep abreast of the latest developments in their field”. I looked at the list of Editorial Board members, but recognised no one, nor many of the institutions. The only UK editorial board member listed was Kenneth Revett of University of Westminster Harrow School of Computer Science. I found their website via Google, but Mr. Revett does not appear on the list of staff.

It’s interesting that the Mining and Metallurgical event(s) is just one (or two) of around 3000 conferences that WASET are organising this year!

What is all this about? Are these legitimate conferences, or just scams to solicit registration fees? Amanda and I did a very quick Google search of WASET, and there were some interesting findings. First of all the WASET open access journal is listed on Beall’s list of potential, possible, or probable predatory scholarly open-access publishers.

Antonio Garcia-Macias found, on checking the website for the next International Conference on Artificial Neural Networks (which is run by the European Neural Networks Society every year), a WASET conference with an identical name scheduled for Amsterdam. It claims to be 34th ICANN, but so far only 22 conferences in the legitimate series have been run, and in 2013 this will be in Sophia in September, not in May in Amsterdam. Antonio concludes that the name has been hijacked and doubts that the conference in Amsterdam will ever take place.

A University of San Diego professor intended to attend a WASET conference in Singapore in 2010, as he was to be in Asia at that time.  As a prerequisite to registration he had to pay 450 Euros into to an account in Dubai. After that all attempts to register failed, as did attempts to contact the organisers and he never recovered his registration fee.

So I thought I would test the water and submit a paper which should not pass even the briefest of technical appraisals, let alone a rigorous peer-review. What better than the essence of last year’s April Fool’s Day blog? Not wanting to spend a lot of time on the “technical content”, I submitted this brief "technical note":

Technical Note
Homeopathic methods provide the key to collectorless flotation
B.A. Wills (MEI, Falmouth, UK) and R. Head (Bodmin Institute, Cornwall, UK)

Abstract
The collectorless flotation of minerals has been one of the Holy Grails of flotation scientists. Although it has been achieved with a few highly hydrophobic materials such as diamond and anthracite, it has had little success with the vast majority of minerals, which have to be persuaded to float by the use of expensive and often toxic reagents. Research in UK has shown that the science of homeopathy may provide the answer.

Introduction
Collectorless flotation of certain sulfides was shown to occur by Trahar and Heyes of CSIRO in 1977. Other authors later researched this subject. Arbiter and Vargas applied collectorless flotation to the recovery of copper from Arizona ores in the late 1980s. They showed it could work on the commercial scale but was not as efficient as flotation with xanthate collectors. Their work is summarised by Arbiter and Gebhardt, These authors concluded that "the need to consider ore geology and to control water quality and redox environments during grinding, conditioning and flotation make commercial-scale collectorless flotation impractical without advances in system controls".

Synopsis of preliminary work
Homeopathy is a controversial alternative medicine, which uses extremely diluted solutions and is claimed to work due to water having a memory, which allows homeopathic solutions to be used without any of the original substance being present (Chaplin, 2007).

We treated a 10% by volume solution of xanthate using a process called succussion, which involves serial dilution of the solution together with shaking and forceful striking on an elastic body; the exact process cannot be disclosed due to an impending patent application.

Each dilution is followed by succussion, until none of the original xanthate in the solution can be detected. However, repeated succussion produces potentization, and the now essentially distilled water memorises the initial xanthate content. We then found that the use of this water in sulphide mineral flotation was as effective as using the original, untreated xanthate solution.

Repeated trials have yet to be carried out, but this potential breakthrough could herald a new dawn in flotation technology, with negligible reagent usage and the concomitant reduction in treatment of environmentally hazardous tailings. Full details and results will be presented at the conference.

References
Arbiter, N. and Gebhardt, J.E., Requirements for Industrial Collectorless Flotation of Sulfide Minerals, Proc. 3rd Int. Symp. Electrochemistry in Mineral and Metal Processing III, R.Woods and P.E. Richardson, Eds, The Electrochem. Soc., 1992.
Chaplin, M.F., The memory of water: an overview, Homeopathy, 96(3), 2007.
________________________________

Within an hour I received an email informing me that my peer- reviewed draft paper had been accepted for presentation, as well as inclusion in the conference proceedings at the conference and for publication in the special journal issues.

Obviously the message here is to avoid such conferences at all costs. At the very best they are suspect. If they exist at all they are no doubt mediocre, and have no place on a calendar of respected international conferences, such as that published on MEI Online.

I would be grateful if you could pass this post to your colleagues, and I would certainly like to hear from anyone who has had experience of WASET, in particular anyone who has actually attended one of these conferences. I would particularly like to have feedback from the organisers!

MEI's Falmouth conferences are only 2 months away

Spring has arrived in Falmouth. The bluebells are beginning to flower, and the top of my head has turned pink, true indicators that summer is just around the corner, and a timely reminder that the next MEI Conferences are not too far away.

Computational Modelling '13 and Physical Separation '13 will run back to back at the lovely St. Michael's Hotel, directly opposite Falmouth's main beach.


Coffee break at St. Michael's Hotel

Both conferences end their first day with a guided walk along part of Cornwall's beautiful coastal path, finishing with beers in the Chain Locker, one of the oldest pubs in old Falmouth town.


Physical Separation '11 delegates on coast path walk

Physical Separation '13 delegates will also have the chance of visiting the historic Camborne-Reduth mining area on the last afternoon of the conference.


MEI delegates on mine tour

More information and useful links:

Computational Modelling '12

June 18-19 2013
Provisional technical programme
Registration details
Accommodation details
Travel details

Physical Separation '13

June 20-21 2013
Sponsored by:

Provisional technical programme
Registration details
Accommodation details
Travel details
Mine tour details

Is progress in energy-efficient comminution doomed?

There is clearly a lot happening in comminution at the moment (see also my posting Where is comminution going).

Progress, or the lack of it, in energy-efficient comminution will be the theme of the keynote lecture at next year’s Comminution ’14 conference in Cape Town. It will be presented by Prof. Tim Napier-Munn, former Director and now Consultant at Australia’s JKMRC. Tim is also a Director on the Board of the Coalition for Eco-Efficient Comminution (CEEC).

Tim’s abstract for the keynote is shown below. It is thought provoking, and we invite your comments, and hopefully your input to next year’s conference.

We are constantly told that comminution is the largest single user of energy on the minesite, and even that it consumes a significant proportion of the world’s electrical power. These two facts are indisputably true; comminution is very inefficient in its use of energy. It would therefore seem that improving comminution energy efficiency should occupy our industry’s capacity for creative thinking more than many of the issues we are asked to confront, especially in a world driven increasingly by the mantra of sustainability. So it is surprising that it barely rates as an issue when companies consider the development of a new mining project or look for operational efficiencies.

The 2012 CEEC Roadmap for Eco-Efficient Comminution taught us that although significant improvements can be made by applying what is already known, the size of the prize is not well understood within the industry. Also current project valuation and discounting practices tend not to identify comminution energy as a significant factor in project optimisation. Other than external regulatory forces, therefore, the motivation for improvement is weak.

There is good theoretical evidence that there is little we can do about it anyway; the physics is against us. In the 1970s Professor Klaus Schonert showed that the most energy-efficient way to break a rock was to place it between two opposed platens and load it until it fractured in tension. This simple mechanism seriously limits the options regarding real innovation in the comminution process. To support this view a glance at a drawing of one of to-day’s cone crushers will show that in all material respects it is identical to a cone crusher manufactured in the 1930s.

The same applies to jaw and gyratory crushers. This is good evidence that the best way to crush a rock was worked out a long time ago and the only improvements since then have been in scale, materials and process control, all of them important but peripheral to the main game.

Schonert’s work led to his invention of the HPGR as a way of increasing the rate at which the crushing action could be usefully applied. Despite intensive research, and early claims of high energy efficiencies, HPGRs have still only succeeded in niche applications in mineral processing after 30 years of trying. AG/SAG mills have dominated grinding because of their capital efficiency and operability rather than their energy efficiency. Stirred mills have been a genuine innovation in fine grinding but even they are prodigious consumers of specific energy. Novel flowsheets, especially those with more effective coarse gangue rejection, have been shown to be capable of significant reductions in overall energy consumption but they are by definition limited by the inherent efficiency of the unit operations they link together. So how are we to achieve the nirvana of paradigm change, say a 50-90% reduction in energy? And do we need to anyway?

We still do not know enough about the physics of the fracture of heterogeneous brittle materials such as mineral ores. Comminution science is really a branch of materials science, but materials scientists are only interested in the fracture event itself (read ‘failure event’), not the nature of the products of fracture as we are. The main job of comminution is mineral liberation, and recent research has taught us that liberation is a product of the texture of the ore and to only a limited extent the fracture mechanism. However we now know that the random fracture assumed by the early liberation models for mathematical convenience is not always the prevailing form. Non-random fracture leading to selective liberation of minerals along grain boundaries can also occur, and it is clearly in our interest to promote such liberation. How is this best done?

Other research has taught us much about what goes on in crushers, tumbling mills and stirred mills. But successful research does not necessarily lead to successful innovation. Innovation is a messy and expensive process with no guaranteed outcomes. How can we translate good research into good technology more effectively?

We really have no excuse for not achieving substantial progress in understanding the comminution process more completely, with the impressive array of experimental tools now available to us including computationally intensive modelling, automated quantitative mineralogy, tomography, breakage testing devices and the like. However capturing this knowledge in a useful form and transferring the lessons to industrial practice is as difficult as it ever was.

In deciding whether there is any hope for significant improvement in comminution energy efficiency, the Comminution ’14 presentation will consider the key technical and cultural impediments to progress, and speculate about how the innovation process may yet provide the long-sought paradigm change.

Call for Abstracts, IMPC 2014

The International Mineral Processing Congress in Santiago, Chile, is next year’s major mineral processing event, and MEI is proud to be media sponsor.

Over 270 abstracts have already been submitted and the deadline for abstract submission is September 30th of this year. Full details can be found on the congress website.

It is 16 years since I was last in Santiago, for Minerals Engineering ’97. It’s a great city, with friendly people, good food and wine and only an hour’s drive to the Pacific Coast and the high Andes.

Don’t miss it!

Margaret Thatcher and the demise of Britain's mining industry

Margaret Thatcher’s funeral today and I can’t remember a time when the nation has been so divided.

Well, yes I can; 1984 the time of the final set piece battle between Arthur Scargill’s mine workers union and the police, ending what was effectively England’s 4th civil war, culminating in the closure of the majority of northern England’s coal mines, and leaving a legacy of bitterness which has lasted to the present day.

Those who vilify Margaret Thatcher for this should try to remember what the 1970s, the pre-Thatcher years were like in the UK.

My late teens and University years were spent in the 1960s, one of the greatest decades to be alive. Barbara and I returned from 4 years in Zambia in 1973 to a Britain that was very much different from the one that we had left in the ‘swinging 60s’. It was a time of austerity; high rates of inflation had forced Edward Heath's Conservative government to impose pay rise capping, which in turn led to unrest amongst the powerful trade unions, as wages could not keep up with prices. The National Union of Mineworkers had ordered its members to work to rule, a result of which was dwindling coal stocks at power stations, associated power cuts, and the 3-day working week, designed to conserve fuel.

And things got worse as the 70s progressed, such that at the end of the decade the dead remained unburied, rats feasted on the refuse rotting in the streets, the Unions held the country to ransom, and politicians had virtually given up. “Crisis, what crisis?” the Prime Minister Jim Callaghan is reported to have said, in 1979 on returning from an overseas visit.

Then along came Margaret Thatcher who, love her or loath her, transformed Britain and put the country back on the international stage.

The coal mines were deep and uneconomic and were bleeding the country to death. Electricity production by North Sea gas was becoming the preferred method. All miners know that the life of a mine is finite, but the Marxist Scargill set out to be the saviour of the pits at all cost, but to no avail, the Iron Lady held out and closures were inevitable, although one can argue that the manner of their closure and the impact on communities was too rapid and severe.

What has been totally overlooked is that at about the same time the few remaining tin mines in Cornwall, which had provided employment for many in the traditional mining areas, shut down virtually overnight, due to a sudden collapse in the tin price. The legacy is similar to that in northern England, with towns such as Camborne, Redruth and St. Just effectively becoming ghost towns and unemployment rife. This is, unfortunately the nature of mining, but these closures brought to an end a long and proud history of metal mining in Cornwall, which had once been the world’s greatest producer of copper and tin.

Despite all her faults Margaret Thatcher was a politician of great conviction, who passionately strived to put England back on its feet and had the courage to stand by her convictions. She certainly polarised opinion then and does so now, although much of the vitriol since her death has been offensive and stems in great part from people who are too young to have lived through the Thatcher years, let alone the decade prior to her office, when Britain was on its knees and needed a very major change in direction and outlook.

Special Comminution issue of Minerals Engineering published

Rather belatedly, as the electronic version has been available for a while, I received Volumes 43-44 (April 2013) of Minerals Engineering this morning, a special issue containing papers presented at Comminution '12.

Comminution ’12 was the 8th in the series of international comminution symposia, and was held at the Vineyard Hotel, Cape Town, from April 17th-20th, 2012. Over 70 papers were presented, from which 19 were selected for publication in the special issue. Draft papers of all the papers presented are available on CD from MEI.

It was particularly encouraging to see industry interacting with academic researchers to develop new techniques, collaboration increasing in importance and developing as a result of networking at conferences such as this. Strong corporate support for the conference is evidenced by the 18 company logos adding colour to the front cover of the issue.

Comminution has an exciting future, and we look forward to reports of new developments at Comminution '14. It was interesting to see a quote from comminution legend Prof. Alban Lynch in this month's MetSoc newsletter :  "Future areas of innovation (in mineral processing) must be in areas like pre-concentration, very fine grinding and classification".

Froth Flotation. Why is it still so intensively researched?

Try explaining nuclear fusion or a car's SatNav to a non-scientist. It's not easy. But explaining the principle of froth flotation is not too difficult- you add chemicals to a mixture of ground ore particles and water, which makes the valuable particles 'greasy' and thus water repellent. You then blow air through the mixture, and the greasy mineral particles stick to the air bubbles and can be skimmed off and separated from the waste.

Simple! So why does this apparently fairly simple process, which was patented over a century ago, attract some of the finest scientific minds in the minerals industry and contribute to a major portion of the peer-reviewed papers published each year in mineral processing journals?

This posting is prompted in part by that of 27th March, and also by an email from Dr. Stephen Grano, of the Universityof Adelaide, Australia, one of my most respected Minerals Engineering reviewers.

Stephen writes: I think a lot of scientists dabble with flotation in their career because it has elements of hydrodynamics, surface chemistry, plant design, froths, etc for a three phase system with mobile gas/liquid interface. So it lends itself to research. But I sometimes wonder where we have got with all the research. The fact is that nowadays a plant metallurgist should be getting >90% recovery and should consider their own position if they are not, with all the tools (QEM-SCAN etc) that are common place. Thirty years ago that was not the case. Thirty years ago people suspected that pyrite in a copper concentrate was activated by Cu ions - now they have proof. But what to do about it...in a plan? I believe that the next step changes will come from new sensors which will be able to measure liberation on-line and surface chemistry on-line. If I were a company, I would not be putting my money into standard surface chemistry research any more. They need sensors in the plant. They know the mechanisms now. The trouble with current sensors like x-ray probes is that it is only a bulk assay and not a measure of liberation. So we are at 90% recovery but can we maintain that for all ores and at lowest possible cost? That means we need to maximise throughput for recovery which means floating coarse composite particles of low liberation. That is another area for research. Do we need more review articles on copper activation and oxidation, and water effects? Do we need more papers trying to increase fine particle recovery by hydrodynamics as it is possible to recover these particles given enough time? We know a lot of that already. One of these days, either next year or in 10 years time or longer, someone will have to say "this is the same as what was published in 1985 or whatever". What I am concerned about is papers that purport to be different but in reality are very derivative or that are pseudo fundamental and justified as being fundamental but in fact don't shed any new light on the matter. I am afraid to say that there are so many now doing flotation that the research has been somewhat commoditised in my view. It may be that more rigorous reviews are required. I get the impression that some researchers think that if it was not in the last 5 years it has not been done. Yet the fundamental questions remain unsolved and continue to be unsolved.

These are provocative words from Stephen, which I hope will promote some serious debate both here and on LinkedIn. Is part of the answer to my eponymous question, as Stephen implies, regurgitation - are journals publishing work similar to that carried out in the past, but now lost in the mists of time? Are we to some extent going round in circles?

I have a feeling that this might be partly true, and is evidenced by the plethora of flotation papers churned out each year at international meetings.

But there is more to it than this. I have argued before about the importance of flotation, indeed that it has my vote for being the most important technological development of the 20th century (6th June 2011). Originally developed to concentrate sulphide minerals, it is now ubiquitous in the minerals industry, treating oxidised ores, oxides, non-metallics and coal. Miners have always 'cherry picked', treating the richest and easiest ores available, such that today the available ores are often low grade and very difficult to treat, and many modern industries demand metals which were virtually unheard of 20 years ago, such as indium, lithium, germanium and neodymium. Intensive research is therefore needed to keep pace with this increasing pressure on the minerals industry.

Today's civilisation is dependent on a plentiful supply of the so- called 'base metals' such as copper, zinc, lead and nickel. Without prior concentration of the valuable minerals in the ore, extraction of the metals from these minerals would be hopelessly uneconomic, effectively making these base metals 'precious metals'. The wealth of information on the flotation of these ores is vast, but even so intensive research on sulphide mineral flotation continues, in the quest for more effective and environmentally friendly reagents, improved circuits and machines, and better ways to control and optimise the process. Base metal mines treat huge tonnages and very small improvements in recovery can lead to huge gains.

In November the world's leading flotation scientists and engineers will meet in Cape Town for Flotation '13, MEI's largest conference. Papers will be presented on the state of the art in flotation technology and the meeting will provide the opportunity for young researchers to network with the major players in this field. The deadline for abstract submission is the end of June and I look forward to receiving papers on cutting edge technology, hoping also that authors make use of the wealth of information stored in the archives over the past 100 years.

The power of Twitter

The world of networking never stands still.

In my posting of 8th January, I remembered how, when Minerals Engineering journal was initiated 25 years go, many professional people did not have email. I formed MEI seventeen years ago, and even then much of our correspondence was by ‘snail-mail’ and very few companies had their own website.

Now everyone has email and it would be inconceivable for any professional not to have a dedicated website.

I feel that Twitter currently has the same status that company websites had around 15 years ago. The problem with Twitter is that is has always had a bad press, partly due to its slightly silly name, and even sillier name for its method of messaging, by means of tweets. It also has the reputation of being trivial, actors, sportsmen etc regularly tweeting to their followers what they had for breakfast, their thoughts on world domination etc.

As networking is a major part of MEI’s business we decided to try it out some time ago, but as my posting (What is the point of Twitter) 3 years ago shows I was highly sceptical of its value, and was wary of telling anyone that I had a Twitter account as this invariably produced supercilious smirks.

However, attitudes are changing and I now see the real potential of Twitter and its power as a networking tool, particularly if you have a message that you want to get out to the wide world.

As you can see from the column on the right, MEI now tweets updates on all the latest mineral processing news from around the world. I am pretty confident when I say ‘all’ the latest news, as we now follow the tweets of the major minerals industry news agencies, and trade magazines and professional societies, all of whom now have active Twitter accounts. Relevant news from these sources is retweeted and appears in our list of tweets.

The point of this posting is that we are trawling trade magazines etc, to find companies who have Twitter accounts, in much the same way as I sought company websites all those years ago. If you are a mineral processing company, we would like to follow you, so that we can retweet your news to a global audience, so I invite you to follow us @barrywills and we will reciprocate.

I would also appreciate any comments regarding your experiences with Twitter.

Where are they now? The 1984 NATO ASI lecturers

 In the mid-1980s two NATO Advanced Study Institutes on mineral processing were held, the first in Bursa, Turkey in 1984, and the second in Falmouth, UK in 1986.

An Advanced Study Institute (ASI) is a high-level teaching activity where a carefully defined subject is treated in depth by lecturers of international standing, and new advances in a subject, not taught elsewhere, are reported in tutorial form. The teaching in ASIs is aimed at scientists at the postdoctoral level with an appropriate scientific background who wish to learn of recent developments in their fields of science.

Each of the ASIs had a duration of 2-weeks in order to give adequate time for the development of a topic and allow for sufficient interaction between the scientists.

I attended both of these ASIs, being co-organiser of that in Falmouth, and it would be interesting to know what became of the lecturers of “international standing” who contributed to these events.

In this posting, I will look at the 1984 ASI, Mineral Processing Design, which was held on a mountain top above Bursa in Turkey . It was the first conference that I ever attended, and certainly the only conference where I have attended all the presentations! It was particularly memorable as I made some life-time contacts at the meeting, but others I have totally lost contact with, and would like your comments if you know what became of them.




The NATO ASI group at Bursa, Turkey, 1984

 I remember being very impressed with a lecture on applied mineralogy given by Bill Petruk of CANMET, Canada. People at that time were only just beginning to be aware of the importance of mineralogy in processing operations, and Bill was probably the authority at the time. I don’t know what became of him, I think I may have met him a couple of times in the late 80s, but his pioneering work has led to the ‘new’ science of geometallurgy, and conferences, such as Geometallurgy ’13 and Process Mineralogy ’14, dedicated to the rapid developments in these areas.



Delegates with NATO lecturers Bill Petruk (4th left),
Gulhan Ozbayoglu (5th left) and Martin Parker (far right)

 I also met for the first time, Gordon Agar of Inco, Canada, who inspired me with a lecture on flotation circuit design which I incorporated, and is still in the latest edition, of Mineral Processing Technology. For many years Gordon was a respected member of the Editorial Board of Minerals Engineering, until his recent retirement.

I have vivid memories of a hard drinking session with Gordon, and another of the NATO lecturers, Dick Burt, during a weekend break from the conference in Istanbul. Dick I had met 10 years earlier when we were both interviewed for the post of lecturer in mineral processing at Camborne School of Mines. At that time he worked for a Cornish mining equipment manufacturer, but later moved into tantalum processing in Canada, and co-authored a book ‘Gravity Concentration Technology’. I met him again 10 years later at Minerals Engineering ’94 in Lake Tahoe, but would love to know what he is doing now.



In Istanbul with NATo lecturers S. Raghavan (far left),
Cornelius Ek (4th left),Dick Burt (5th left) and Gordon Agar (6th left)



Gulhan Ozbayoglu (far right) at last year's IMPC

 I also met for the first time Gulhan Ozbayoglu, who gave an excellent lecture on coal preparation. During our time in Bursa, I learned that our grandfathers had both fought, on separate sides, at Gallipoli in the Great War, both being wounded, Gulhan’s mortally. We took a day off from the conference and visited the war memorials at the Dardanelles with her family. I have been in touch with Gulhan ever since, and have caught up with her at many conferences, the last being at the IMPC in New Delhi last year.

Other NATO lecturers I have heard nothing of since the ASI, but would certainly like to know what became of H.W. Smith of the University of Toronto, who presented a lecture on data reconciliation, Martin Parker, of the University of Salford, UK, who was the magnetic separation specialist and S. Raghavan of the University of Arizona, who was a member of the Editorial Board of Minerals Engineering for a few years. I also totally lost contact with one of the editors of the proceedings of the conference, Baki Yarar, who I believe is now Emeritus Professor of Mining Engineering at the Colorado School of Mines.

I really would be grateful if anyone can provide the whereabouts of any of these people.

Latest design improvements increase spiral concentrator efficiency

Spiral concentrators have, over numerous years, found many varied applications in mineral processing. Until relatively recently, all spirals were very similar, based upon the original Humphreys design, which is now obsolete. However, in recent years there have been considerable developments in spiral technology, and a wide range of devices is now available. The main areas of development have been in the introduction of spirals with only one concentrate take-off, at the bottom of the spiral, and the use of spirals without added wash water.

Spirals are now made with slopes of varying steepness, the angle affecting the specific gravity of separation, but having little effect on concentrate grade and recovery. Although a simple device, the separation mechanisms are complex, stratification being due to the combined effect of the differential settling rates of the particles, the effect of interstitial trickling through the flowing bed and the mild centrifugal force, often being likened to the stratification of particles in a river as it flows around a bend.

Southern and Northern
Hemisphere Spirals

A small team of workers at the Bodmin Institute in Cornwall has shown that this centrifugal force can be enhanced by that produced by the spin of the earth. Under the leadership of research director Dr. Corrie Hayles, they have shown that the orientation of the spiral pitch has an effect on performance, an anti-clockwise flow performing better in the UK than a spiral with a clockwise flow. Dr Hayles calls these spirals northern hemisphere and southern hemisphere devices respectively. He is now keen to develop collaboration with workers in the southern hemisphere to assess performance of the two devices, and he would be interested to hear from anyone who has any thoughts on this.