Tuesday, 17 August 2021

Prof. Raj K. Rajamani, 1948-2021

There was very sad news this week from USA of the sudden death last Friday of popular University of Utah Professor Raj Rajamani. He was well known for his work on comminution, particularly the discrete element simulation of ball mills and semi-autogenous mills, and for his contribution to computational fluid dynamics.  Most recently his successful research included contributions on high pressure grinding and electrodynamic sorting of light metals and alloys.

Prof. Rajamani at Comminution '10 in Cape Town

Raj graduated from the Dept. of Chemical Engineering at Annamalai University, Madras, India, in 1969. He obtained an M. Tech. in Chemical Engineering from the Indian Institute of Technology, Kanpur, in 1971, before moving to the University of Utah, where he completed his M.E. Chemical Engineering in 1973 and a Ph.D. in Metallurgy, in 1979. He then joined the staff of the Department of Metallurgical Engineering, becoming a full Professor in 1994.

In 2009 Raj was the recipient of the SME's Antoine M. Gaudin Award, “For his seminal work in the application of discrete element methods in the modeling of charge motion in semi-autogenous and ball mill grinding, and for his contribution to the basic science of comminution and classification”. Other awards include the SAG High Flyer Award in 2001 for outstanding contributions toward the development of autogenous and semi-autogenous grinding technology, and the Mellow Met Award for Excellence in Teaching in 1995, Department of Metallurgical Engineering, University of Utah.

Our thoughts at this time are with Raj's wife, Sudda, and their two daughters, and I invite all of you who knew Raj to leave your memories in the comments below.

Sunday, 15 August 2021

Developments in flotation circuit diagnostic practice

An important role of a site metallurgist is to diagnose reasons for problems in a flotation circuit and devise strategies to overcome these problems. Traditionally this has involved performing and analysing information from a flotation circuit survey. 

It is difficult to determine from this information alone definitive flotation mineral recovery mechanisms and strategies for circuit improvement. There are, however, new analytical and modelling techniques that can be used to complement traditional survey data. These techniques are able to determine the effect of mineralogy, surface chemistry and circuit design on flotation circuit recoveries and grades. They can suggest strategies for improvement which would not have been identified via a conventional circuit audit. 

In her keynote lecture at Flotation '21 Dr. Kym Runge will review these new approaches and use an industrial example to demonstrate the type of conclusions that can be derived. The developments that are required to improve analysis turnaround times and enable assessment of alternative flotation circuit options will be outlined.  

Associate Professor Kym Runge is the leader of the Separation Research Program at the SMI-JKMRC, Australia.  This program aims to develop novel separation processes that will make a step change in mining and involves research into high voltage comminution, coarse particle flotation, improved classification and novel flotation chemistries.  Prior to this appointment, Kym worked 25 years as a flotation specialist.  Her research has involved the development of flotation simulation and diagnostic procedures at the SMI-JKMRC, including the development of JKSimFloat, a flotation simulation program.  She also worked 10 years for Metso, the biggest mining equipment supplier, as a flotation consultant and researcher.

Updates on the conference are at #Flotation21 and the deadline for abstracts is the end of this month.

Thursday, 12 August 2021

"Diseases to which Miners of Metals are Exposed": the observations of Bernardino Ramazzini (1633-1714)

I am grateful to Dr. Franklin White for the following historical review of the early 18th century De Morbis Artificum: Diseases of Workers by Bernadino Ramazzini.

Franklin is the author of the recently published biography of his father, Frank White, Miner with a Heart of Gold (posting of 21st September, 2020) and of the historical reviews of De la Pirotechnia and De Re Metallica.

Introduction: Emerging Sciences of the Late Middle Ages

Expanding European economies during the fifteenth and sixteenth centuries spurred demand for gold and silver, as a basis for currencies as well as for jewelry.  As underground mining expanded to meet this demand, recognition and concern for the health and safety of miners and metal workers increased. 

The first publication dealing with the hazards of an occupation was a brochure written in 1472 by Ulrich Ellenbog, a physician of Augsburg, Germany.  His focus was preventive: to inform goldsmiths and others working with gold and silver how to avoid the toxic effects of such metals as mercury and lead.[1]

The first published account on the ill-health of miners and ways of preventing this was published by Agricola in 1556, in his famous treatise De Re Metallica.  However, this account was secondary to his detailed descriptions of mining and smelting.[2] 

Eleven years later, in 1567, the first monograph on the occupational diseases of miners and smelter workers, appeared in Germany. Its author was Theophrastus Bombastus von Hohenheim, also known as Paracelsus. Entitled Von der Bergsucht oder Bergkrankheiten (on Miners’ Sickness and other Diseases of Miners), he discussed etiology, pathogenesis, prevention, diagnosis and therapy.[1]

Agricola and Paracelsus were “renaissance men”: broadly educated in the arts, botany, mineralogy, mining, medicine, and natural philosophy.  Among other initiatives, they inspired a movement among physician-scholars focused on the health hazards and consequences of different fields of work.  

The first full scale treatise focused entirely on occupational health was De Morbis Artificum diatriba, a dissertation by Bernadino Ramazzini (1633-1714), a physician-scholar of Modena, Italy.[3] 

About Bernardino Ramazzini

Ramazzini was born in 1633 at Carpi, an ancient town dating from the Etruscan culture of north-central Italy. It was then known for its straw plaiting industry, and today remains an active industrial and crafts centre. Earning a medical doctorate at Parma in 1659, he continued his studies in Rome. He then practised as a public physician in the towns of Canino and Marta in Viterbo province. On moving to Modena in 1671, he was in favour with the ducal family of Este.[1] When the University of Modena was established in 1678, he was appointed Professor of the Theory of Medicine.[4] Addressing public health issues such as epidemic typhus, he can also be viewed as an epidemiologist. 

In 1700 he was appointed chair of Practical Medicine at the University of Padua, where he launched his De Morbis Artificum diatriba (published at Modena in the same year). Based not only on his clinical observations, it drew from his innumerable visits to worksites where he observed actual hazards associated with different occupations. From this he developed his core principle: 

“a prudent diagnostician will inquire first of all as to a new patient’s occupation, since the condition of the humours… is profoundly affected by the kind of work in which he is engaged.”[3]

He recognized that how people lived and worked directly influenced their health:

“Many an artisan has looked at his craft as a means to support life and raise a family, but all he has got from it is some deadly disease, with the result that he has departed this life cursing the craft to which he has applied himself”[3]

At that time, when the attention of doctors was devoted to the most wealthy patients, it was unexpected and unusual that a doctor devoted his attention to investigate workers’ health issues.[4]

“…many of our own clinicians would laugh at any… professor… if they saw him… descending to explore regions underground so as to investigate the hidden recesses of nature… But let them learn from… Galen (129 – c. 216) …who went down into… (a ferrous sulphate cave-mine)… to a depth of about one-eighth of a mile and observed… green water dripping into a pool… of a suffocating and almost intolerable odor…” workmen hastily carrying out this acidic water.[3]

He understood the connection between working conditions, health and public policy: 

“Not only in antiquity but in our own times also laws have been passed...to secure good conditions for workers; so it is right that the art of medicine should contribute its portion for the benefit and relief of those for whom the law has shown such foresight...”[3]

De Morbis Artificum diatriba 

Each chapter of the “diatriba” describes a disease(s) associated with a particular type of work followed by supporting literature where it existed, workplace descriptions, questions and advice for workers, and remedies. He recognized that not all workers' diseases were attributable to exposures to chemical or physical agents in the work environment: many appeared to be caused by motions and postures. 

In the first edition, Ramazzini discusses 42 groups of workers, the very first chapter – perhaps most notably - being devoted to miners. Of potential interest to modern miners are chapters on gilders, chemists, potters, tinsmiths, glass workers, sulphur workers, blacksmiths, gypsum and lime workers, stone cutters, and salt makers. A second edition, published in 1713, added 12 more groups, including coppersmiths, grinders, and brick makers.[3]  He died in the following year, at the venerable age of 81 years. 

"Diseases to which Miners of Metals are Exposed."

This chapter opens with the generic statement:

“Various and manifold is the harvest reaped by certain workers from the crafts and trades that they pursue; all the profit they get is fatal injury to their health… from two causes. The first and most potent is the harmful character of the materials that they handle, for these emit noxious vapours and very fine particles inimical to human beings and induce particular diseases; and second I ascribe to certain violent and irregular motions and unnatural postures of the body, by reason of which… serious diseases gradually develop therefrom.”[3]

He quotes the ancient Roman poet Ovid (43 BC – 17/18 AD):

“Men go down into the bowels of the earth, and what she has hidden away and consigned to the Stygian shades they dig out, wealth, provocative of evils.”[3]

He immediately acknowledges that Ovid was referring to moral evils, but then argues that the same statement may be applied to “the evils that attack men’s bodies”, listing examples such as the following (my medical translations in parentheses):[3] dyspnoea (shortness of breath), phthisis (tuberculosis), apoplexy (unconsciousness), paralysis (loss of motor function), cachexy (wasting), swollen feet (self-explanatory), joint pains, and palsy (loss of motor control e.g., tremors). He emphasizes:  “…the lungs and brain of … workers are badly affected, the lungs especially.”[3]

He considered mercury mining the most lethal, citing Gabriele Falloppio that “mercury miners can hold out for barely three years”, and Michael Ettmuller that within four months “they become subject to palsy of the limbs, paralytic, and suffer from vertigo” … caused by “the mercurial spirits which are… injurious to the nerves.”[3]   These descriptions remain consistent with 21st century medical science. 

He notes: 

“…mines are either damp because water keeps settling at the bottom of the shaft, or they are dry, and… fire sometimes has to be used… in splitting the rocks.  In damp mines that contain stagnant water the legs of the miners are affected, not only by the dense and poisonous vapours… but also… when the fragments of split rock fall… and… workers are suffocated and fall headlong… Moreover… when (fire)… is needed to soften rocks it elicits… pernicious fumes from the mineral substances, so that the… miners are plagued by every one of the elements.”[3]

He makes the following social commentary: 

“The mortality of those who dig minerals is very great, and women who marry men of this sort marry again and again.”[3]

Among his sources, he cites Agricola, Lucretius, Bernardo Cesi, Jesuit author of Mineralogia (1636), and Ramelow who wrote a German treatise on paralysis and palsy among metal workers, among others. He refers to works of art depicting slavery in ancient mining, pointing out that the conditions of his own day are not necessarily improved upon this. He advocates to church leaders.[3] 

Conclusion

Bernadino Ramazzini is considered the founder of the field of occupational medicine. His “diatriba” gave prominent attention to the diseases of metal miners, while addressing ultimately the health implications of some 54 occupations. He is aligned with the “scientific revolution”, a transformative period for ideas across mathematics, physics, astronomy, and biology based on verifiable evidence. Translated into French, German and English, Ramazzini’s book remained the major text for this branch of preventive medicine until the early 19th century when industrialization created new complexities requiring new approaches.

References

1. George Rosen.  Introduction to the Translation. Diseases of Workers by Bernardino Ramazzini. New York Academy of Medicine. The History of Medicine Series. No. 23 Hafner Publishing Company. New York, London 1964.
2. Franklin White. De Re Metallica: treatise of Georgius Agricola Revisited. Annals of the Royal College of Physicians and Surgeons of Canada. 1994;27:163-6.
3. Bernardino Ramazzini. Diseases of Workers. Translated from the Latin text. De Morbis Artificum of 1713 by Wilmer Cave Wright. 546 pages. Academy of Medicine. The History of Medicine Series. No. 23 Hafner Publishing Company. New York, London 1964.
4. Giuliano Franco. Editorial. A Tribute to Bernardino Ramazzini (1633-1714) on the tercentenary of his death. Occupational Medicine. 2014; 64(1):2-4. 

Monday, 9 August 2021

Future flotation circuits and machines

There have been major innovations in flotation machines over recent years, which has led to developments and improvements in flotation circuits.

So where is all this going, what will flotation circuits look like in future years, and what will be the major developments in flotation machine design?

This will be the subject of one of the panel discussions at Flotation '21 in November and we seek your views on this, which will be of help to the chairman of the conference, Peter Amelunxen, Vice-President of Technical Services for Flotation '21 sponsor Hudbay Minerals, Canada, and the first recipient of the MEI Young Person's Award back in 2011.

Peter Amelunxen with the 2018 Young Person's Award winner,
Dr, Zhiyong Gao, at Flotation '19

Under Peter's guidance a flotation plant consisting entirely of Jameson Cells has been built at Hudbay's New Britannia operation (posting of 7th April 2020), with Glencore Technology engaged for technical support. Flotation '19 gave the Hudbay team an opportunity to discuss results, share ideas, and build relationships with Glencore and with Prof. Graeme Jameson, the inventor of the eponymous cell.

We are privileged to have Prof. Jameson on the panel. A Laureate Professor at the University of Newcastle, Australia, he has been honoured as a Fellow of perhaps the most prestigious scientific organisation in the world, the Royal Society (posting of 15th May 2018) . He has presented research papers at all MEI’s Flotation conferences and was a keynote lecturer at Flotation ’09 with his paper New Directions in Flotation Machine Design. He is a long-standing member of the Editorial Board of Minerals Engineering and is the recipient of many major awards, including the Australian Prime Minister’s Prize for Science.  In 2013 he was awarded the SME’s prestigious Antoine Gaudin Award in Denver and I was pleased to nominate him for International Mining’s Hall of Fame, into which he was inaugurated in 2014. In 2016 he was the recipient of the IMPC's Lifetime Achievement Award. Prof. Jameson's life and work will be the subject of the first keynote lecture at the conference, given by Prof. Jim Finch, also a recipient of the  IMPC Lifetime Achievement Award and the Antoine Gaudin Award.

Profs. Jameson and Finch at Flotation '15

Professor Jameson has made an outstanding contribution to the Australian economy and the environment as the inventor of what is considered by many to be the nation's biggest export earner in the last 25 years. In the true mark of a scientist, 30 years on from his initial breakthrough discovery, and at the age of 85, he is still fine-tuning and improving the Jameson Cell, and pushing the boundaries of flotation with his new invention the coarse flotation NovaCell, which he feels is much more important, because if flotation can be achieved at coarser particle sizes less grinding is needed, using less energy and resulting in less wear and tear on the grinding equipment. 

There should be interesting discussion on coarse flotation between Prof Jameson and fellow panelist Dr. Eric Wasmund, the Vice President of Global Flotation Business with Flotation '21 sponsor Eriez Flotation Division, Canada. Eriez invented and market the Hydrofloat Cell, for flotation at coarse particle sizes, and the Eriez Flotation product line encompasses flotation cells, gas spargers, mini-pilot plants, slurry distributors and flotation test equipment. The company has designed, supplied and commissioned more than 900 column flotation systems worldwide for cleaning, roughing and scavenging applications in metallic and non-metallic processing operations.  It is also well known for its StackCell®, a small stackable mechanical cell offering reduced mixing in the cell and shorter residence times, which was featured, along with the Hydrofloat Cell, at Flotation '19

Eric Wasmund (2nd left) at the Eriez booth at Flotation '19

Dr. Dariusz Lelinski, the Global Product Director of sponsor FLSmidth, USA, has been a regular contributor to the flotation series. A respected mineral processing expert with international experience in product and process design, test planning, results evaluation, survey and industrial operation support, he will lead the FLSmidth team which will launch the WEMCO nextGEN flotation machine at the conference.

Dariusz Lelinski (2nd left) at Flotation '19. Also in the picture are Martin Rudolph (left)
and Romke Kuyvenhoven (2nd right) who will be involved
with the first panel discussion at Flotation '21

Prof. Juan Yianatos, of Santa Maria University, Chile, is the 4th member of the panel. Juan was President of the XXVII IMPC, which was held in Santiago, Chile in 2014. A long serving member of the Minerals Engineering Editorial Board, he will bring to the panel his expertise in applied research on process modelling, diagnosis and control, particularly in flotation including column flotation.

Juan Yianatos with Prof. John Monhemius
at the IMPC in Quebec, 2016

We look forward to a dynamic panel discussion, and a reminder that if you would like to make a presentation at the conference, abstracts should be submitted by the end of this month.  Updates can be found at #Flotation21.

Thursday, 5 August 2021

Major green company Metso Outotec to sponsor Sustainable Minerals '22

Sustainability is a top priority for Metso-Outotec, so it is great to be able to announce that they will be sponsoring Sustainable Minerals '22 next year, joining ZEISS Microscopy as early sponsors.

The year 2020 was transformational for Metso Outotec, who started as two companies and by the 1st of July had formed the new company, whose vision is to be the customers’ number one choice for sustainable use of earth’s natural resources. The company has set Science Based Targets (SBT) in alignment with limiting global warming to 1.5°C. They aim to reduce CO2 emissions by 50% in their own production by 2030, 20% in logistics by 2025 and 20% in product use phase by 2025. They are also targeting that 30% of the supplier spend by the end of 2025 is with partners who have set a SBT emission target. 

In January Metso Outotec was ranked 8th on the Corporate Knights 2021 Global 100 Index of most sustainable companies in the world, and placed as a top-ranking company among its peers. We are more than proud to have Metso Outotec involved with Sustainable Minerals '22.  Thanks also to our media partner, International Mining, and industry associates CEEC, Critical Minerals Association and Cornwall Mining Alliance.

There is now a first call for abstracts for the online conference, and updates will be posted at #SustainableMinerals22.

Sunday, 1 August 2021

July update: no end in sight for the pandemic

The pandemic still rages on, fueled in England by mass gatherings, such as the G7 summit in Cornwall in June (posting of 1st July) and July's major sporting events in London. The 2-week Wimbledon tennis tournament was watched by thousands, while at Wembley Stadium the semi-finals and final of Euro 2020 were attended by tens of thousands of football fans. There were egregious scenes inside and outside the stadium during the day of the final, where thousands of ticketless louts broke down barriers and entered the stadium, swelling the anticipated 60,00 attendance who watched England, in their first major final since the World Cup in 1966, lose on a penalty shoot-out to Italy. Days after the match it was reported that swathes of England fans had tested positive for Coronavirus

The final was part of a Government trial to test the safety of large events, allowing 60,000 fans to attend with no social distancing or masks after producing a negative test result. However, this did not allow for the thousands more who congregated outside and the dozens of ticketless fans who stormed the stadium.

Fans leaving Wembley stadium during Euro 2020

Despite Covid infections having risen to their highest level since early February, one of the highest in the world, hospitalisations and deaths are low, thanks to the NHS and the impressive vaccine roll-out, over 65% of adults in UK being fully vaccinated by the middle of the month. PM Boris Johnson therefore declared a very contentious 'freedom day' on July 19th, where virtually all Coronavirus restrictions were lifted, and we mere mortals were advised to behave sensibly and to make our own decisions on wearing masks, social distancing etc.

Crowds behaving sensibly during Euro 2020

Ironically two days before 'freedom day' the new Health Secretary Sajid Javid tested positive for Coronavirus, and Johnson and chancellor Rishi Sunak were both contacted by the NHS Track and Trace but decided not to self-isolate as it was said that they were taking part in a pilot programme where daily tests replace self-isolation, once more strengthening the feeling that there is one rule for the elite... Three hours later, amidst a tide of criticism, they decided that self-isolation was indeed the right thing to do!

Johnson's lifting of restrictions has been widely condemned worldwide, health experts calling it "a threat to the world", some experts worrying that the UK could become a breeding ground for variants. Even England’s chief medical officer, Prof. Chris Whity, conceded that the number of people in hospital with Covid in the UK was doubling about every three weeks and "could soon reach quite scary numbers”. He said “I don’t think we should underestimate the fact that we could get into trouble again surprisingly fast.” Having said that, there was a puzzling and rapid decline in infections on the last week of the month, giving rise to cautious optimism that the third wave of Covid might have turned the corner in the UK. The next few weeks will tell.

No matter what happens, the world is still a long way off opening to international travel and even some easing of restrictions hasn't reduced the nightmare of border control where people have been queuing for hours to show they are Covid-negative.

Although there have been a number of hybrid conferences- a mixture of online and face-to-face activities- none have been truly international, and it is likely to be a very long time yet before this happens. All MEI Conferences this year have been online, as will November's Flotation '21, originally scheduled for Cape Town. Comminution '22, also scheduled for Cape Town, has been postponed for a year, and Physical Separation '22, IntegratedMinPro '22 and Sustainable Minerals '22 are all online. Who know what will happen after that?

@barrywills