Thursday, 30 July 2015

New Book- Plant Auditing

Plant Auditing: A Powerful Tool for Improving Metallurgical Plant Performance is the first book ever written to show how to get maximum benefit out of an audit. This comprehensive guide is easy to follow with numerous charts and checklists. It walks the reader through the complexities of setting up the right kind of audit, the type that will provide actionable steps to profitable outcomes. Also included are 20 case studies illustrating real-life problems typically encountered at plants that can be resolved through the audit procedures described in this book. 

The author, Deepak Malhotra, has more than 30 years of experience in metallurgical and mining auditing. A Gaudin Award recipient, he is eminently qualified to write this first book on plant auditing.

Since leaving AMAX in 1990, he has been president of Resource Development, Inc., a mining and metallurgy consulting and testing firm. He has served in several SME leadership positions, including chairing several international symposia.

The book is available from the SME.

Monday, 27 July 2015

Nickel, Cobalt and Precious Metals Conferences

MEI has for several years been a media partner for the ALTA series of conferences, held annually in Perth, Australia. These conferences are held over 5 days in May and cover the processing of nickel, cobalt, precious metals, copper, uranium and REE ores.

MEI's Precious Metals and Nickel-Cobalt conferences are held back to back over 4 days and this year were also held in May, which with hindsight was not a great idea.

In order to separate the two conferences, and to give workers in these fields the opportunity of networking with workers in opposite ends of the world, the next conferences in the MEI series will be held in October 2016, often a good time of year in Falmouth.

Precious Metals, and Nickel and Cobalt Processing are MEI's smallest conferences, but they provide excellent networking opportunities (see reports on Precious Metals '15 and Nickel Processing '15), with delegates from many countries discussing innovations and common problems with the aim of optimising plant operations. This is particularly important at times of depressed metal prices, and they could not be more depressed than at the present time, with the gold price recently falling to a 5-year low (see also an interesting discussion on LinkedIn- Low Metal Prices- Problem or Opportunity?). So we look forward once again to researchers and operators from around the world meeting in Falmouth in 15 months time.
Delegates at Precious Metals '15 relaxing in Falmouth
Full details of the conferences, including Calls for Abstracts, can be found at Precious Metals '16 and Nickel and Cobalt Processing '16.

Friday, 24 July 2015

July Cornwall and Devon Sundowners

Falmouth's Chain Locker pub was probably a hard act to follow after my two previous sundowners this month in the most exotic of locations, by and on the Zambezi River in Zambia (posting of 13th July). But it was good to be back at the quayside last night to meet up with around 20 regulars and a few CSM students who were celebrating their graduation this week.


On 3rd July over 30 Wolf employees, contractors and visitors congregated at the Miners’ Arms, Hemerdon to celebrate the start of ore commissioning at the Drakeland's Tungsten-Tin mine (see also
posting of 25th June), and Process Plant Manager Charlie Northfield has sent me this update:

Commissioning of the Drakelands process plant commenced on 23 June with the first ore introduced at the ROM bin. Commissioning of the primary and secondary crushers, rotary scrubber and tertiary crushers has been successfully completed. Commissioning of the fines gravity circuit including the deslime cyclones, spiral concentrators and shaking tables has also been completed. Preparations for commissioning of the DMS (dense medium separation) circuits is well advanced.

Renowned tin and tungsten expert Ron Goodman joined the team of consultants assisting the commissioning team. Ironically Ron assisted in the commissioning of the Wheal Jane tin processing plant in 1971 – the last metal mine to open in the UK! Ron is shown below (centre) with former AMAX project manager Roger Craddock (left) and AMAX mining engineer Paul Lister (right).

GR Engineering Services celebrated a successful week of commissioning. Shown below are process engineers Sean Sara, Alan Bax, David Ng, Graeme Perkins (commissioning manager) and Steve Hoban.

Wolf employees Henry Chalcraft, Andrew Harry, Adam Bromley,
Joseph Bentley and Tony Delany

Management software consultant John Ferris with Wolf Minerals’ Operations Manager Jeff Harrison and CFO Richard Lucas

Wolf’s Tania Bradford (training officer), Amy Hatswell (HR administrator), Dawn Parish (Senior HR officer)
and Kerry Dee (HR Manager)

Wednesday, 22 July 2015

Nature's Paradise: Chobe, Botswana

During our recent stay in Zambia's Mosi-oa-Tunya National Park for the SAIMM Copper-Cobalt Conference we spent a day in Botswana in the Chobe National Park.

The Zambian side of the border at Kazungula
The excellent Bushtracks Safaris drove us the 70 km from Livingstone to Botswana, and dealt with the chaos at the border crossing at Kazungula on the north bank of the Zambezi. The island in the middle of the river, which we crossed by ferry, is the quadripoint where Zambia, Zimbabwe, Namibia and Botswana meet. Long lines of trucks line the road on both banks of the river, and until the planned road bridge is completed wait for up to two weeks to make the ferry crossing!

A short drive took us into the Chobe National Park, named after the river which empties itself into the Zambezi. Botswana's first National Park, it has one of the highest populations of game in Africa, being particularly famous for its numerous huge herds of Kalahari elephants, the largest in body size of all living elephants. The Chobe region contains an estimated 120,000 elephants, the highest concentration in the world. Damage caused by these high numbers is obvious in this wonderful landscape and culls have been considered, but are too controversial and have thus far been rejected.

Elusive Sable Antelope

We were lucky to visit in the dry season where the huge herds were in profusion along the bank of the Chobe River. Barbara and I have visited most of the great National Parks of Africa over the years, in East Africa, South Africa, Zimbabwe, Namibia and Zambia, but never have we been to an area where wildlife literally teems, and apart from elephant we saw more hippo, crocodile and buffalo than anywhere else, and even managed to sight one of the shyest and most elusive of antelopes, the magnificent sable, only our second sighting ever, the first being 44 years ago - in Chobe!

During our day in Chobe we spent the morning on a cruise on the river, and after an excellent lunch at the Chobe Safari Lodge, an afternoon drive along the river bank.

The real purpose of this blog posting is to highly recommend this visit to any of you who are staying close to the area, be it in Zambia, Zimbabwe, Namibia or Botswana. It is a truly great experience in what is our favourite African National Park.

Below are more photos taken during our day, including very close encounters with elephants when we became completely surrounded by a huge herd.

Cape Buffalo in the dramatic scenery

A very large Nile Crocodile takes to the water







Monday, 20 July 2015

In conversation with Douglas Fuerstenau, a mineral processing legend

Prof. Doug Fuerstenau is one of the giants of mineral processing, a living legend. For six decades he has been a familiar figure at AIME/SME Meetings and International Mineral Processing Congresses (IMPCs), and presented a keynote lecture at the last IMPC in Santiago. In fact he has been an active participant in all of the International Mineral Processing Congresses, starting with the 6th Congress in Cannes in 1963 through to last year’s event.
Prof. Fuerstenau (2nd right) with Barry Wills, Pradip and Juan Yianatos in Santiago, 2014
From 1978 to 1998, he served as the American Member of the Steering Committee and the Scientific Committee of the IMPCs and he was the first recipient of the IMPC Lifetime Achievement Award in 1995 in San Francisco at the 19th IMPC.
Receiving the IMPC Lifetime Achievement Award in 1995
With Eric Forssberg and John Herbst
The Lifetime Achievement Award was just one of very many awards that he has received during his illustrious career, but he considers the proudest moment was when he was elected to the National Academy of Engineering in 1976, considered the highest honour for an engineer in the United States.
Douglas Winston Fuerstenau was born on December 6th, 1928 and raised in South Dakota, during the dust bowl days of the Great Depression. His first six years were spent on the family farm. Times were hard and he was no stranger to hard work, taking jobs where he could find them. But his parents always kept higher education in mind for their children, and becoming an academic was the key goal in his life. After living in a number of small towns, his family moved to Rapid City, SD, in 1943 during his high school years where he recalls two superb high school teachers who inspired him towards a technical career. One was his mathematics teacher and the other his chemistry teacher. 
Panning for gold in the Black Hills in May 1947
Able to graduate a year early from high school in 1945, he entered the South Dakota School of Mines and Technology as an undergraduate, with the initial aim of studying chemistry, later changing his major to metallurgical engineering. His growing interest in Black Hills minerals oriented him towards mineral processing. Two professors there come quickly to Doug’s mind: Prof. Walter Rosenblith who taught him physics (Rosenblith left for MIT where he eventually became provost and was later elected to all three U.S. National Academies) and Prof. Paul Gries who taught mineralogy. For four different summers he worked in the metallurgical industry: two summers for US Steel in Chicago (1947 for the Metallurgical Department in the rolling mills and 1948 in the open hearths), one summer at Bunker Hill Lead Smelter in Kellogg, Idaho, and the final summer in the copper-zinc-gold flotation mill of Howe Sound Co. in Holden, Wash. He feels that those summer jobs were very important in his career development.
Montana School of Mines, 1950

 After graduating in 1949, Doug continued his education at Montana School of Mines in Butte, MT, where he received an MS degree in 1950, studying under Prof. Donald W. McGlashan. He considers this to be the beginning of his conducting systematic research on flotation fundamentals. Butte was an exciting place to be at that time because all of the Anaconda mines were then in full operation, mostly underground copper mines but also lead, zinc and manganese mines.
In September 1950 he enrolled as a graduate student at the Massachusetts Institute of Technology (MIT) in the Mineral Engineering Program within the Department of Metallurgy, working directly under Prof. Antoine M. Gaudin. His doctoral thesis research involved using electrokinetic methods to delineate adsorption phenomena in the flotation of quartz. During Doug’s final year as a graduate student, Prof. Gaudin had invited Prof. J. Th. G. Overbeek (of DLVO fame) from Holland to spend a year in the mineral engineering group. He credits Overbeek with instilling in him a solid, quantitative background in interfacial science. From the lectures of Prof. Overbeek and also those of Prof. R. Schuhmann (well known to mineral processors for the Gaudin-Schuhmann size distribution), he concluded that prepared and well-organized lectures would be his own method of classroom teaching.
The photo below, taken at the time of Professor Overbeek's departure, is particularly memorable to Doug. It was taken at the end of summer in August 1953, the year in which he received his doctor's degree (ScD), became an Assistant Professor at MIT, and married Peggy.  Overbeek included this photo in a compilation many years ago about his work and his life. From the left are Harsukh Modi (Doug's first graduate student), Richard J. Charles (grad student who later formulated the Charles Law of Comminution), new Assistant Professor Doug Fuerstenau, Professor Overbeek, Assistant Professor Philipp L. deBruyn, postdoctoral researchers Dirk Stigter and Horacio Bergna, and graduate students Jean Tournesac and Ken Larson.
On his appointment as an Assistant Professor of Mineral Engineering, Doug began his extensive teaching and research activities in the extraction of minerals and metals from ores. After deciding to further his practical background, in 1956 he accepted a position as Section Leader in the Metals Research Laboratories of Union Carbide Corp. in Niagara Falls, NY, where he worked primarily on problems involving the processing of raw materials for the ferroalloy and battery industries. In 1958 he moved to Kaiser Aluminum and Chemical Corp. at Permanente, CA, as Manager of Mineral Engineering, where he directed the program for assessing potential bauxite deposits as a source of alumina. Before joining Kaiser, he had told them of his interest in returning to academia, and in 1959 Doug became a member of the faculty in the Department of Mineral Technology at the University of California at Berkeley, to which he has been associated ever since. 
One of the many visitors to Berkeley:
Prof. Prakash Kapur
At Berkeley he taught some undergraduate courses but most of his activities were at the graduate level, including not only classroom teaching but also supervising the research of graduate students at the master’s and doctoral degree level. Wanting his graduate students to have a full bag of intellectual tools, he directed his graduate students to taking courses that expanded their background either towards the broad aspects of interfacial science or to process engineering, depending on their aims and interests. In those years, Doug knew personally most of the world’s leading researchers in surface and colloid chemistry, particle technology, and extractive metallurgy as well as mineral processing; and his former students have often stated how valuable it was for them to meet and hear seminars from the steady stream of visitors to Berkeley. To date, 65 students completed their MS theses under his supervision and 60 their PhD theses, and of those 24 entered academic careers either for all or part of their professional life. Beyond his teaching duties, from 1970 to 1978, he served as the chair of the Department of Materials Science and Engineering (the department was renamed through the years).
In recognition of his teaching, Prof. Fuerstenau received the Distinguished Teaching Award from UC Berkeley and the Mineral Industry Education Award from AIME. Through his research, he has made numerous seminal contributions to mineral processing and the allied areas of particulate technology, surface chemistry, mineral processing unit operations, and mathematical modeling of processes. His early personal contributions included development of the hemimicelle concept of self-assembly of adsorbed surfactant ions at the mineral/water interface and also the electrostatic model of flotation that applies to systems where separations are controlled by surface charge in the electrical double layer. At MIT, he modified the Hallimond tube so that it could be used to obtain reproducible results and started its widespread use as a tool to help delineate the physical chemistry of flotation.
Reflecting back on his feeling that Prof. Gaudin jumped from one research topic to another, Doug’s planned approach to research when he arrived at Berkeley was to delve deeply into a given area with several consecutive graduate students continuing investigation of that topic. In the 1950s, Gaudin had a very large single research contract from the AEC (Atomic Energy Commission) that provided blanket support for the entire mineral engineering program at MIT, so he could suggest that a new student work on any topic of interest to him at the time. On the other hand, Doug received research support at Berkeley from a range of sources, including many grants from industry but mainly from such federal sources as the National Science Foundation, Department of Energy, the National Institute of Health, the Bureau of Mines, etc.
His research interests expanded in two directions: control of the behavior of mineral particles through interfacial chemistry and the engineering processing of solid particles, both generally oriented towards problems in mineral processing. With graduate students, notable contributions were made to surface and colloid chemistry, flotation fundamentals, the flotation chemistry of a wide range of minerals and coal, selective flocculation, hydrometallurgical recovery of metals from deep sea manganese nodules and carbon recovery of gold, comminution fundamentals, modeling of ball mills and high-pressure grinding rolls, pelletizing and agglomeration fundamentals, particle technology including mixing and transport of solid particles. He has published some 450 papers, mostly coauthored with graduate students. His research has not only laid out the scientific principles of many unit operations but also has pointed the way towards improving process efficiency, reducing energy consumption, and enhancing environmental remediation. His accomplishments have led to his receiving many awards from AIME/SME (the Hardy Gold Medal, the Raymond Award, the Richards Award, the Gaudin Award, the Frank Aplan Award, the Taggart Award, SME Distinguished Membership, and AIME Honorary Membership). Recently, he received the Particle Technology Lifetime Achievement Award from AIChE.
Receiving the Hardy Gold Medal from AIME in 1957
Prof. Fuerstenau has been actively involved with professional society matters, largely AIME/SME committees and programs. However, over the years he also was an active participant in Engineering Foundation Research Conferences, European Comminution Symposiums, various particle technology conferences, and domestic and international surface chemistry conferences and workshops. He has served on panels and advisory committees of the National Research Council, National Science Foundation, Dept. of Energy, Dept. of Education, and also on advisory and visiting committees to numerous universities. He has also been on the editorial boards and committees of a wide range of journals, for 25 years being Editor-in-Chief of International Journal of Mineral Processing. He edited the classic AIME book, Froth Flotation – 50th Anniversary Volume.
He served as a member of the Board of Directors of Homestake Mining Company for 22 years, until his retirement in 1999 and in recognition of his many major contributions to education and research, the South Dakota School of Mines and Technology established the Douglas W. Fuerstenau Professorship in metallurgical and materials engineering there. In 2011, the Bancroft Library of the University of California published his oral history, entitled, Mineral Processing Engineer and Scientist: In Education, Research, Industry and International Cooperation.
Underground in the Fimiston Mine, Kalgoorlie, 1992
It is evident from the above that Doug Fuerstenau is no ivory tower academic. His illustrious career has been a unique blend of industry and academia, and during this long career he has achieved much and met many interesting people, some of whom we could also describe as mineral processing legends. I know that he was inspired by Prof. Antoine Gaudin, who was first his teacher and then a colleague. I asked him what kind of a man was Prof. Gaudin, and why is he considered one of the greats of mineral processing, and what did he think Gaudin’s greatest legacy is.
Profs. Gaudin and Fuerstenau at Berkeley, 1965
Doug said that he considers three persons, all giants in their fields, to have been his primary mentors. The first was Professor Gaudin who solidified his interest in mineral processing fundamentals and after whom he broadly patterned his academic career. Doug observed that as a professor in a research university, Gaudin could work on scientific problems with students while at the same time be involved with industry. He credits Professor Overbeek from Utrecht with providing him with a rigorous background in surface and colloid chemistry and showing how to apply basic physical chemistry to solving applied problems. He credits Professor Hans Rumpf from Karlsruhe to cementing his interest in particle science and technology and applying that to mineral processing.  
With Professor Hans Rumpf in Berkeley 1972
Two other persons also influenced his professional life in mineral processing, namely, Professor Don McGlashan at Montana School of Mines and Rush Spedden briefly at MIT but mainly at Union Carbide. Spedden was a talented mineral processing engineer with a vast knowledge of applied mineral processing whose leadership role in research management influenced Doug in his approach to research managing. Two persons with whom Doug had a long association and often sought their counsel on educational matters over the years were John Elliott, Professor of Process Metallurgy at MIT, and Milton Wadsworth, Professor of Extractive Metallurgy at the University of Utah. Both were 7 or 8 years older than Doug and he valued their insight. Three very close friends, personally and professionally, who played a very major role in his life and his work, were Frank Aplan (from South Dakota) beginning in 1946, Tom Healy (Australia) beginning in 1960, and Klaus Schoenert (Germany) from 1965 until his passing in 2011.
Klaus Schoenert in Berkeley by the HPGR in 2003
What kind of a person was Gaudin? When Doug entered MIT, Gaudin was considered the world leader in mineral processing (or mineral engineering as Gaudin termed the field) and he was held in great respect not only by his students but by professionals internationally. Doug defines Gaudin as being a very understanding person who had real interest in the welfare of students and in the careers of former students. He knew how to handle people and could adroitly smooth out ticklish situations. 
Gaudin had very good vision, a penetrating mind, and an insatiable appetite for learning, as exemplified by his bringing Overbeek to MIT for a year to enhance the mineral engineering program’s background in applied surface and colloid chemistry. He was creative and had a steady stream of new ideas that led to the proliferation of research topics. He could express his ideas and concepts both with spoken and written words with clarity and force, his spoken words having a hint of a French accent. He could exhibit a bit of sly humour, with a bit of a smile. One always knew if he had walked into a laboratory because of the residual cigar aroma.
Gaudin did have a short temper that would show once in a while and he could have some volatile comments. He did not suffer fools gladly. During Doug’s years as a student at MIT, Gaudin taught three courses for graduate students; they were not prepared lecture courses but were merely discussions of chapters that he had finished in preparing the second edition of his flotation book. Perhaps consulting occupied much more of his time than it should have. With students he always maintained a certain amount of French formality. As Doug’s association with him progressed over the many years, memos and letters from Gaudin progressed through the sequence: A.M. Gaudin, Antoine Gaudin, Tony Gaudin, and finally to Tony.
Doug considers Gaudin’s legacy to be catalyzing the role of engineering science in mineral processing research and development. An example is his introduction of careful well-characterized experimentation to uncover the scientific nature of the flotation process and to his formulating many of the interfacial principles that control flotation separations. The same can be said for his 1926 seminal comminution paper. During his decade at Montana School of Mines he showed how detailed characterization of particles in industrial flotation operations could be used to improve process performance, initiated investigations of flotation collector adsorption, and wrote two ground-breaking influential textbooks, Flotation in 1932 and Principles of Mineral Dressing in 1939. After moving to MIT, he had access to using radioactive tracers and was then able to make advances through direct measurements of reagent adsorption in numerous flotation systems.
 Over those decades, Professor Gaudin certainly had the largest number of advanced students in mineral processing, and particularly in flotation in the English-speaking world. Those graduate students and their progeny students are also a part of his legacy that will last, passing on the philosophy of research. Interestingly, Gaudin himself considered his greatest achievement to have been the development of ion exchange processes for the recovery of uranium from very low-grade ores. Doug considers Gaudin’s role to have been far broader.
Doug’s career in mineral processing has spanned over 65 years during which time he has seen many, and participated in some, advances in the field. In 1950, grinding mills and flotation cells were small, and the larger the concentrator, the larger the number of ball mills and flotation cells. Once the principles of scale-up were elucidated and structural design factors addressed, there has been an ever increasing size of flotation machines and grinding mills. In the area of comminution, autogenous grinding mills and SAG mills were introduced and cyclones replaced classifiers. The major recent comminution innovation was Schoenert’s invention of energy-saving high-pressure grinding rolls (HPGR), first widely installed in cement plants but now are taking hold in the hard rock mining industry. High-gradient magnetic separators were invented. As for innovations in flotation machines, the flotation column gained acceptance in cleaner circuits and in coal flotation. Doug commented that there have been a number of process innovations during the last few years, such as transforming taconite from a rock into an ore through a lengthy investigation of grinding, mineral separating, and pelletizing. The last decades have witnessed expanded applications of hydrometallurgy such as solvent extraction for copper recovery, the carbon-in-pulp and carbon-in-leach process for gold processing, high-pressure oxidation of sulfides, heap leaching, agglomeration in heap leaching, and bacterial leaching and processing. Flotation processing has seen a steady introduction of new reagents, including collectors, depressants and frothers. Coal flotation has become a significant component of coal preparation plants.
Mineral processing research involved the engineering science related either to operations and processes or to the fundamental science underlying those processes. The engineering science investigations were heavily concerned with modeling comminution and flotation. In the latter half of the 20th Century, population balance models were applied to the accurate modeling, scale up, and simulation of ball mills and other comminution operations. Studies of particle breakage led to better understanding of comminution principles and finally to the invention of the HPGR. Circuit analysis was carried out and applied to operating mills. The engineering science underlying agglomeration was developed and applied to improving balling systems. Because mineral separations are largely based on interfacial phenomena and surface behavior has significant effects when dealing with fine particles, surface chemical investigations continue to be the subject of much work. Flotation dominated the research on mineral separations, some of that to advances in flotation kinetics but most of it directed towards investigation of collector adsorption, including delineation of the surface chemistry, crystal chemistry, electrochemistry, and solution chemistry involved. Real progress has been made for two reasons: one is that there is better understanding of the chemistry and physics of surface chemical reactions and two, as laboratory equipment becomes more advanced, there are new tools with which to probe more deeply into delineating the phenomena. Similarly many advances have been made in hydrometallurgy, including leaching and solvent extraction.
At the Centenary of Flotation Symposium, 2005 with Profs. Janusz Laskowski and Kari Heiskanen
Modern froth flotation was born 110 years ago. Professor Gaudin and Doug were involved with flotation chemistry research for 90 of those years. Doug considers that the scientific basis of flotation has been put on firm ground. Being asked if there is much life left in flotation research or are we just going round in circles, Doug pointed out that nearly all of the published research has involved representative mineral systems, and because we have moved fast there still is much left behind. For example, an area essentially left behind that has become critical and currently is receiving a lot of attention is the flotation separation of the rare-earth minerals. Future research should be addressed to try to fully understand the flotation surface chemistry of other less common but important minerals where viable separations are needed. As new concepts and understanding come onto the scene, they should be applied to mineral systems left behind. Probably more attention should be directed towards the surface chemistry of depressants, Eh control, fine particle flotation, and also coarse particle flotation to reduce the amount of energy spent on grinding. Doug considers that research is necessary because research results beget new ideas and new directions. Furthermore, it is a training ground for advanced mineral processing scientists and engineers.
With Sir Ian Wark in 1983
Areas to be targeted in mineral processing include increasing the energy efficiency of unit operations and processes in treating ores, improving recovery in mineral processing operations, consider green chemistry in reagent production, continue research in hydrometallurgy, in-situ mining, resource conservation by addressing the cradle-to-grave cycle of a metal, total resource recovery, look out for opportunities of turning a rock into an ore as was the case for taconite.
It would be remiss of me not to mention Doug’s younger brother Maurice, also a major force in mineral processing, and who I was fortunate to meet for the first time in Seattle in 2012, shortly before his untimely death at the age of 79 (posting of 9th October 2012). Doug and Maurie were very close and regularly consulted each other on professional matters. Maurice Clark Fuerstenau was born in 1933 in South Dakota. By 1955 he was a senior, majoring in geological engineering at the South Dakota School of Mines and Technology and had to do a short BS thesis. For this, Doug suggested that he measure the effect of alkylammonium chlorides on contact angles on sylvite (KCl), which eventually resulted in a joint paper on the flotation chemistry of alkali halides. Maurie did not want to pursue a career in geological engineering, and Doug suggested that he apply for graduate study in the mineral engineering program at MIT. That led to Maurie’s MS and ScD thesis research on thickening, working directly under the supervision of Professor Gaudin. Maurie had a long and successful academic career in mineral processing and was highly recognized as a leader in flotation and hydrometallurgy. 

Profs. Maurice Fuerstenau, Antoine Gaudin and Doug Fuerstenau
in Golden, Colorado, 1974
It has been a great pleasure and a privilege to interview Douglas Fuerstenau, perhaps the greatest living mineral processing legend. Although he is an outstanding scientist I found him to be a true gentleman, unassuming and very approachable. I look forward to our next meeting, probably at next year’s SME Meeting in Phoenix.

More Conversations

Thursday, 16 July 2015

The Smoke That Thunders

Of all the places that I have visited in the world, the Mosi-oa-Tunya (the smoke that thunders), better known as the Victoria Falls, is the most wondrous. "Real Africa" has become a bit of a cliché but this area of the mighty Zambezi, the 4th longest river in Africa, is just that- real Africa, wild and magnificent.

The spray from the Falls rises out of the African bush
Zambia September 1969

This month I visited the Falls for the 7th time, and the experience never palls. Barbara and I first passed through here in 1969, en route to the Zambian Copperbelt from Cape Town (posting of 25 November 2010), but in all our subsequent visits we have been based on the Zimbabwean side of the river. This time we spent a week on the Zambian bank, thanks to the SAIMM Copper - Cobalt Conference at the Avani Victoria Falls Resort near the town of Livingstone and situated in the heart of the Mosi-oa-Tunya National Park. The Zambezi forms the border between Zambia and Zimbabwe, so the falls are shared by the two countries, and the park is 'twin' to the Victoria Falls National Park on the Zimbabwean side.

Victoria Falls is roughly twice the height of Niagara, but while it is neither the highest nor the widest waterfall in the world, it is classified as the largest, based on its width of 1,708 metres (5,604 ft) and height of 108 metres (354 ft), resulting in the world's largest sheet of falling water.

To appreciate the full grandeur of the Falls you must take to the air, so we took a short helicopter tour to view the full width of the Zambezi plunging into the awesome crevice in the relatively flat plateau.

Geologically Victoria Falls is the result of soft sandstone that fills huge cracks in the hard basalt rock of the plateau. As the Upper Zambezi flowed across the plateau in ancient times, it found the cracks and started wearing away the softer rock, eventually creating a series of deep gorges. Geologists estimate that the river has been falling into these gorges for at least the last 100,000 years. As the rock wears away, the cataract follows these gigantic cracks and moves further upriver across the plateau.

The first of the series of gorges
The Victoria Falls bridge from the Boiling Pot

From the first gorge the river takes a zigzag course through the gorges. When it travels through the second gorge, it passes along a pool known as the "Boiling Pot." During high water this part of the river is filled with heavy turbulence and whirlpools. It is often at this location that objects, animals, and sometimes people, are deposited along the edge of the water after they have been unlucky enough to have been swept over the falls.

A short walk down to river level in the boiling pot is definitely worth the effort and always a good place to relax and talk to local people as the river races towards the Victoria Falls bridge which spans Zambia and Zimbabwe, and also the location of one of the world's most famous bungee jumps.

Meeting friendly locals by the Boiling Pot
The river continues zigzagging through a total of six gorges, which range from 400 to 800 feet (120-240m) deep, before settling into a steep-walled chasm known as the Batoka Gorge which is filled with wild rapids, providing one of the world's most spectacular white water trips. In the distant past, each of these gorges has been the location of an earlier version of Victoria Falls which has moved further upstream as the river has eroded away the sandstone. After travelling a further 120 miles (200km) the river empties into the man-made Lake Kariba, and then on into Mozambique and the Indian Ocean.

From the Zambian bank of the river the well maintained trail begins at the Eastern Cataract and leads to the Knife Edge bridge, which often provides a drenching due to the close proximity of the falling water, and then on to the view across the second gorge and Danger Point in Zimbabwe.

The Eastern Cataract
The Victoria Falls and Knife-Edge bridges

Crossing the Knife-Edge Bridge

The Falls viewed from the second gorge
Looking across the second gorge to Danger Point in Zimbabwe
No visit to the Falls is complete without viewing from the Zimbabwean side, and we walked across the Victoria Falls Bridge into that beautiful country, like Zambia populated by friendly people, despite its economy and tourist industry being ruined by its despotic leader. But things are obviously improving, and Victoria Falls town was vibrant with many street cafes, and new luxury lodges have sprung up since our last visits, such as the Victoria Falls Safari Lodge, where we stopped for coffee and from the decking watched shy kudu drinking from a small waterhole, watched with interest by vultures in a nearby tree.


Victoria Falls Hotel is one of the great hotels of Africa. We first stayed there in 1970, and expected faded Victorian elegance this time, but were pleasantly surprised to see it in pristine condition, and had an excellent lunch on the terrace with the Mosi-oa-Tunya in the distance.

The magnificent Victoria Falls Hotel, Zimbabwe


Then along the track from the hotel to the Rain Forest, to pay our US$30 entrance fee to view the Falls!

The Devil's Cataract

The Main Falls
Approaching Livingstone Island
Sitting in the middle of the river on the very edge of the abyss is Livingstone Island. It was here that the Scottish missionary and explorer David Livingstone was taken by dug-out canoe, and became the first European to view the Falls on 16 November 1855. As was the tradition in those times, he named them after his Queen. In his diary he wrote: “....scenes so lovely must have been gazed upon by angels in their flight.” We visited the island for High Tea and a wet and muddy tour to view the Falls from only a metre or so from the 350 ft plunge, the highlight being a rather scary, but unforgettable, dip in one of the deep pools by the long drop.

An extreme close-up view of the Falls from the Livingstone Island rock pool

A view of the rock pool from the Rain Forest
From only a short distance upriver it is hard to imagine that the river will soon take its precipitous plunge into the giant crack in the surrounding plateau, and a cruise on the Zambezi is a wonderful way to enjoy an evening sundowner, watching hippos in the tranquil waters while Africa provides one of its spectacular sunsets.

Cruising the tranquil Zambezi

Further upriver the Chobe River in nearby Botswana empties itself into the Zambezi, and we spent a day across the Botswanan border in Chobe National Park, famed for its teeming wildlife, particularly the greatest concentration of elephants anywhere in the world.
By the Chobe River, Botswana
This was a short break that I would recommend to anyone. A very relaxing way to see "real Africa" without the long demanding drives that we have experienced in East Africa, Limpopo and Namibia. However, be aware that what you see at Victoria Falls is very seasonal, due to the distinct rainy and dry seasons in this part of Africa. The minimum flow, which occurs in November, is around a tenth of the April figure; this variation in flow being greater than that of other major falls. July is usually an ideal time for visiting this area. Although it is easily accessible from Cape Town if you are attending an MEI Conference, there is a fair chance that after a November conference, at the end of the dry season, the Falls may be less than spectacular, as the photo below shows, taken during my visit in September 1995.

The "Falls" in September 1995
I can guarantee, however, that if you visit after a March or April conference you will be rewarded by an awesome spectacle of the Falls in full flood, although this is not a great time for photography, or for keeping yourself and your camera dry!

"Viewing" the Falls in full flood

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