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A monthly publication devoted to scientific transactions and specialist technical topics is unlikely to be on the priority reading list of the majority of the mining and metallurgical community. But it is the ambition of the Publication's Committee to make the Journal of much wider interest to our general membership from technician trainees to mine managers to CEO's of our constituent companies. It is to entice general readership that some 1200 words of valuable space are devoted to the Journal Comment each month. This is intended to highlight some of the features and impact of the papers to excite and activate attention.

To entice this preliminary glance before confining the publication to the book shelf or even the wpb, the author has to call on a large measure of journalistic licence in style, titles and quotations. It is essential to be spicy, controversial and even provocative to separate it from the abbreviated authoritative but necessary scientific style of the bulk of the contents.
The Journal Comment aims to be an enticement to dig into some important feature of the papers in the issue. For this reason it has been decided to include it as a separate item on the Institutes Web Site. This might provoke those who enjoy twittering, blogging and googling to submit comment and criticism, all of which will be welcomed and responded to. At least it is proof that somebody has read it.
R.E. Robinson

Copper Cobalt Edition July 2023

K.C. Sole 11092023The African Copperbelt, which stretches some 500 km in length, roughly following the northwest–southeast border between the Democratic Republic of Congo (DRC) and Zambia, contains more than 10% of the world’s known copper deposits, and hosts the highest concentration of industrial activity in sub-Saharan Africa outside of South Africa.

In 1867, Scottish missionary and explorer David Livingstone first described the smelting of ore into copper ingots by people living in the Katanga area, who had
known and worked the deposits for centuries. Formal exploitation in the DRC (then Belgian Congo) began when the railway line reached Elizabethville (now Lubumbashi) in 1910, under Union Minière du Haut-Katanga (which was nationalized in 1967 as Gécamines, La Générale des Carrières et des Mines). During the early 1930s, this was the largest copper-producing company in the world. Commercial copper mining in Zambia started in 1909 at Broken Hill, Northern Rhodesia (now Kabwe, Zambia). However, exploitation of these ores has long been one of the most complicated geopolitical and economic questions of the region, not only because of colonial (and later nationalistic) rivalries, but also because of the energy-intensive requirements of smelters—pyrometallurgical processing then being the only known technology for treating copper ores.

The first hydrometallurgical operation, comprising leaching and direct electrowinning, started up at Jadotville (now Likasi) in 1929, producing 30 kt/a of copper cathode. This technology could be economically operated at smaller scale, with a lower energy requirement, and in a less technically demanding environment than the traditional pyrometallurgy route. The Luilu operation started in 1960, with leaching and electrowinning for 150 kt/a copper production, as well as producing cobalt metal. Hydrometallurgical processing of copper oxide ores took a major step forward when the inclusion of a solvent extraction step prior to electrowinning was proven at the Tailings Leach Plant (now Konkola Copper) in Zambia in the 1970s. This technology allowed much higher cathode purity to be obtained than could be achieved by pyrometallurgical processes at that time.

Much of the latter part of the 20th century was characterized by rises and falls of the copper price, nationalization and denationalization of the mining industry in both countries, brutal civil wars, assassinations, abrupt changes of governments, many decades of political and economic instability and corruption, and the DRC falling to rank among the poorest countries in the world. Some stability was finally restored to the region in the early 2000s, prompting a cautious return of investment and industrial activity.

In the past 15 years, the DRC has experienced a huge resurgence of activity, with an impressive proportion of the capital spending, project development, operational expansions, and metal value production in the Southern African mining industry now located in this region. The geology and mineralogy of the deposits differ significantly from those in other major copper-producing regions of the world, the ores often having very high grades as well as the presence of cobalt. Both mining and metallurgy present some unique difficulties, not only technical, but also with respect to logistics, supply chain, and legislative issues; however, the region is blessed with large resources of oxide ores, mainly at relatively shallow depths, and a young, ambitious, and eager-to-learn workforce.

The high-grade oxide ores have enabled relatively rapid construction, commissioning, and ramp-up of numerous Copperbelt hydrometallurgical operations in the past decade to produce London Metal Exchange Grade A copper cathode. There are now nearly fifty production sites in the DRC, where copper cathode output has grown from almost zero in 2008 to 1.77 Mt in 2022, and is anticipated to exceed 2.50 Mt by 2025. More than 70% of the world’s recent new projects are in the DRC, accounting for more than 90% of new copper cathode capacity. Earlier this year, the DRC overtook Chile as the leading global producer of hydrometallurgical copper.
Pyrometallurgical production has not been abandoned, however: Ivanhoe Mining is planning the first new smelter in several decades to treat concentrate at the giant Kamoa–Kakula project in the DRC, which is ranked as the world’s largest high-grade copper deposit. Zambian processing has traditionally also focused heavily on pyrometallurgical routes.

The DRC also produces almost 70% of the world’s cobalt. In the 1960s, the highest-quality cobalt cathode in the world was produced at the Luilu plant near Kolwezi (now Kamoto Copper), which hosted engineers from Japan and the USA who came to learn from the African operations. Today, cobalt production from this region has become highly emotive and politicized: some 20% of the country’s supply is sourced from artisanal miners (estimated to exceed 100 000 in the Kolwezi area alone), often working in highly dangerous conditions and employing child labour. Cobalt is an essential component in many formulations of lithium-ion battery cathodes, considered critical to a low-carbon future; however, the precarious nature of the supply chain is driving technological development towards elimination of cobalt from these batteries. Cooperation and good faith between governments, legislators, multinational mining companies operating in the region, and labour are required to ensure that this window of opportunity for cobalt is not missed.

Despite ongoing difficult environments in the Copperbelt mining industry, industrial investment in this region is accelerating, mainly driven by Chinese-owned companies. To supply energy and electrification requirements to meet global decarbonization and sustainability goals, demand for copper is predicted to increase by some 20% by 2030; estimated cobalt demand is somewhat lower. As a major producer of these critical and strategic metals, the African Copperbelt is now slowly positioning to regain some of its former glory as a technical leader and major player on the world mining stage.

Crooks, S., Lindley, J., Lipus, D., Sellschop, R., Smit, E., and van Zyl, S. 2023. Bridging the copper supply gap. Declercq, R. 2022. Katanga and the American world of copper: mechanization, vertical integration, and territorialization of colonial capitalism, 1900–30. Born with a Copper Spoon: A Global History of Copper, 1830–1980. Declercq, R., Money, D., and Frøland, H.O. (eds). UBC Press, Vancouver. pp. 253–273. Etheridge, L. Not dated. Copperbelt region, Africa.
Tinkler, O.S. and Sole, K.C. 2023. Copper solvent extraction on the African Copperbelt: From historic origins to world-leading status. Journal of the Southern African Institute of Mining and Metallurgy, vol. 123, no. 7. pp. 349–356.

K.C. Sole
Chair of the Organising Committee:
Copper Cobalt Africa 2023 (PhD, PrEng, FSAIMM, FSAAE)

The Value of Variety

DFD Malan 30062023This edition of the Journal contains five general papers on a variety of topics. Three of the papers deal with rock engineering issues, one deals with spontaneous combustion, and another with soiling of solar reflectors or heliostats. The three rock engineering papers each cover very different challenges faced by the mining industry.

Squeezing rock conditions occur when tunnels located in weak, ductile rock masses are overstressed. Unlike the strong, brittle rock masses typically encountered in deep South African gold mines, which fracture and burst when overstressed, these weaker rock masses deform excessively, resulting in gradual closure of the tunnels until they are no longer serviceable. Support needs to be designed to manage squeezing rock conditions without rockfall incidents, and to keep the tunnels serviceable. The paper on this topic represents an update of an earlier benchmarking exercise on squeezing ground management in Australian and Canadian mines, taking into account advancements in deformation monitoring technologies and the increased availability of yielding ground support elements. The authors provide practical guidelines for predicting the level of squeezing, selecting appropriate support systems, and rehabilitation.

Another rock engineering paper deals with pillar design in Himalayan rock salt mines. The authors describe a comprehensive field testing exercise using flat jacks to determine pillar stress.

Monitoring and predicting the performance (overbreak and underbreak) of open stopes is essential for minimizing dilution, ore loss, and disruptions to the mining cycle to ensure profitability. Most open stoping operations perform cavity monitoring surveys of all stopes. The paper on open stope performance describes an improvement on the classic empirical methods for predicting overbreak that includes prediction of underbreak. The method was developed using machine learning techniques.

Spontaneous combustion is a common problem in coal mines, which causes environmental and safety and health problem risks. Another paper deals with the potential for spontaneous combustion and ground reactivity in carbonaceous shales at an opencast iron ore mine, and highlights the importance of determining the properties of the carbonaceous shale.

The soiling of solar reflectors (heliostats) is perhaps an unusual topic for inclusion in the Journal. However, concentrating solar power (CSP) technology is likely to play an important role in the energy transition, particularly for energy-intensive industries such as smelting. This paper addresses the soiling rate due to dust from a ferromanganese smelter, and its effect on heliostat performance.

W.C. Joughin

Research on pillar strength

DFD Malan 30062023This edition of the Journal is the first of a series of planned themed editions. The South African mining industry faces several engineering challenges and it is hoped that these themes will stimulate research and groundbreaking papers. The first of these challenges is to develop local pillar strength equations and pillar design methodologies for hard rock mines. The shallow chrome, platinum, and manganese mines in South Africa typically use mechanized bord-and-pillar mining layouts. The older operations are gradually increasing in depth and this adversely affects the extraction ratios. The available design methodologies and pillar strength formulae dictate an increase in pillar size and a decrease in extraction ratio with depth. As these mining operations are vital to the South African economy, it is critical to maximize the extraction ratios and to ensure that the orebodies are optimally exploited. For outsiders, it is therefore somewhat surprising to learn that the layout designs are still mostly based on the Hedley and Grant pillar strength formula, which was originally developed for Canadian uranium mines in the early 1970s. Since then, very little research has been conducted to develop reef-type specific pillar strength formulae for the hard rock mines in South Africa. Considering the importance of this aspect, it is remarkable that a dedicated research programme to address this issue was not established a long time ago.

In contrast, extensive research into coal pillar strength was conducted in the aftermath of the Coalbrook disaster in 1960. The famous Salamon and Munro power-law strength formula was the result of this research effort. Interestingly, the selection of a power-law equation was inspired by laboratory and underground experiments that were conducted much earlier in the 1940s and 1950s. These studies indicated that the strengths of square pillars of the same height vary as the square root of their widths. The strengths of pillars of the same width also vary in inverse ratio to their height. This was generalized by Salamon in a power-law formula with the familiar exponents α and β. These exponents were subsequently calibrated using a database of failed and intact pillars. For the hard rock strength formula, Hedley and Grant used the same references from the 1940s and 1950s, as well as Salamon’s work, to motivate the use of a power-law equation. It is not clear, however, if the calibrated exponents apply to the reef types in the South African mines. Almost no collapses have been reported in the Bushveld Complex mines using this pillar formula, except where weak clay layers were present. This may indicate that the current designs are possibly too conservative. It also presents a difficult problem to researchers, as a database of failed and intact pillars for bord-and-pillar layouts cannot be compiled. The statistical approach followed by Salamon to calibrate an empirical strength equation for coal can therefore not be replicated for hard rock. Attempts have been made to use small UG2 and Merensky Reef crush pillars for such an analysis, but most of these crush pillars are at a similar mining height, they are irregular in size, and it is difficult to classify them as failed or intact based on visual observations.

This special edition of the Journal is therefore a welcome addition to the available research literature on pillar strength and we thank the authors who contributed papers. The work includes interesting studies on the use of a limit equilibrium pillar model in a boundary element code, laboratory studies to calibrate these models, underground observations of pillar behaviour, the effect of confinement on pillar strength, and the effect of pillar shape. Professor John Napier made many of these studies possible with his TEXAN displacement discontinuity code, and the authors are deeply grateful for his contribution in this regard.

D.F. Malan

Lithium – Many metallurgical challenges

MDworzanowskiAbout 40 years ago lithium was a metal of curiosity. Its production was limited due to limited demand. Lithium was only produced from spodumene concentrate. Then, of course, along came lithium-ion batteries. As the demand for lithium-ion batteries has grown exponentially, so has the need to extract lithium from different sources.

Lithium is the only metal for which production from naturally-occuring solutions is as important as production from hard rock deposits. Dissolved lithium occurs in brines across many parts of the world, in the form of lithium chloride, which has an extremely high solubility. The primary source is salar (salt lake) deposits in South America. Dissolved lithium also occurs in oil and gas field brines as well as geothermal brines. The most important form of hard rock lithium is spodumene (lithium aluminium silicate), with Australia being the leading producer.

The metallurgical extraction of lithium from these different sources poses many challenges. The most important point to remember, is that purity is king! Battery-grade lithium carbonate and lithium hydroxide require purities of >99.8% and >99.9% respectively. This places enormous demands on selectivity and purification during the processing of the various sources of lithium.

Let us start with lithum in brine. It is easy to imagine that because the lithium is already dissolved, a large part of the metallurgical work has already been done. Well, you would be mistaken. Unfortunately, all the various brines contain many impurities. When production of lithium from brine started in South America, evaporation ponds were (and still are) used to concentrate the lithium. The concentrated brine then reports to a lithium carbonate plant where a long sequence of purification steps leads to the production of battery-grade lithium carbonate.

The location and lower lithium concentration of oil and gas field brines as well as geothermal brines means that evaporation ponds are a non-starter. Over the last 5 years there has been a significant development of direct lithium extraction (DLE) technologies, using ion-sieve, ion exchange, or solvent extraction. These techniques allow the selective extraction of the lithium from the brine, and are followed also by a sequence of purification steps. DLE plants are in operation in China and there is one in Argentina. There are many DLE projects in development and its application looks promising.

The issue with extracting lithium from hard rock deposits is that it is very energy intensive. Crushing and grinding are required, followed by DMS and/or flotation, to produce a spodumene concentrate. The concentrate then requires calcining and roasting steps before leaching and purification. Alternative less energy-intensive options are being studied but their possible application is still on the horizon.

Production of waste streams is also an issue for lithium extraction. In the case of salars, the evaporation ponds produce huge stockpiles of sodium, potassium, magnesium, and calcium salts. There are no markets close enough for these salts. Hard rock lithium extraction produces DMS or flotation tailings, which require tailings dams. It also produces a sodium sulphate by-product for which there is not always a market. The beauty of DLE is that the waste product, brine minus most of the lithium, can be reinjected back into the brine reservoir.

Given the very stringent purity requirements for battery -lithium hydroxide, many lithium projects are considering the electrolytic production of lithium hydroxide from purified lithium chloride, which is based on the chlor-alkali process used for producing sodium hydroxide from sodium chloride. The problems with this approach are the significant energy consumption and the large volumes of concentrated hydrochloric acid by-product, for which there is not always a market.

In summary, lithium metallurgical extraction faces many challenges in terms of producing the required product purities for lithium batteries, reducing waste production, and also the reduction of carbon footprints.

M. Dworzanowski

Mining projects in the UK and the community

D TudorThe three major mining projects currently under way in the UK involve rail, coal, and fertilizer. They are all at various stages of the project cycle.

HS2, the controversial high-speed rail project, was originally envisaged to connect London to Manchester and Leeds via Birmingham by 2033. Economics and politics have had a major impact on the final cost – up from an initial £35 billion to over £100 billion, and on the final route – the Birmingham Leeds link has been scrapped. However, work goes on and HS2 has once again begun tunnelling under London after launching its third giant tunnel boring machine (TBM) near Euston station. Following a longstanding tradition of naming TBMs after women, members of the local community have selected the name ‘Lydia’ for the TBM. Lydia Gandaa is a former teacher at the nearby Old Oak Common Primary School and a founding member of the Bubble & Squeak social enterprise in the area. She is an active member of the local community, running after-school and holiday clubs at the Old Oak Community Centre.

The new coal mine in Cumbria is a project near Whitehaven that will produce 2.8 million tons of coking coal a year for steelmaking and create 500 new jobs. It was approved by the UK government in January 2023, despite objections from local, national, and global groups over its climate impact. The mine will emit about 9 million tons of greenhouse gases a year, equivalent to putting 200 000 cars on the road. Most of the coal mined will be exported. The UK Climate Change Committee condemned the decision and said it contradicted the global effort towards net zero. Climate campaigners have been denied the opportunity to institute a legal challenge against the government over its decision to grant planning permission for a new coal mine in Cumbria. The project was initially approved by Cumbria County Council in October 2020. West Cumbria Mining, the firm behind the project, promised to create 500 direct jobs and 1500 in the wider community.

The Woodsmith project is Anglo American’s new polyhalite fertilizer mine that is being developed in the northeast of England near Whitby. Polyhalite is a naturally occurring mineral that contains potassium, sulphur, magnesium, and calcium plus numerous micronutrients, making it an ideal natural fertilizer. The project is currently sinking two mine shafts over a mile deep near Sneaton, south of Whitby and a 37 km long tunnel to a processing area at Wilton on Teesside.

After an investment of £400 million in 2022, Anglo announced that the capital expenditure for this year will be £650 million and approximately £800 million per year for the following three years – a significant investment for the local area.
The project currently employs over 1650 people at its sites in Whitby, Teesside, and Scarborough, with the majority being from the local communities.

The Woodsmith Foundation is an independent charity funded by Anglo American and has recently awarded grants totalling almost £250 000 towards initiatives that will support local communities from Teesside to Scarborough.
Seventy organizations received grants from the Foundation to help them deliver a range of programmes. For example, Scarborough Pride will use their grant to offer meaningful support and activities for the LGBT+ community in the Scarborough Borough. The Loftus Town Council will use their grant to start a gardening club for residents.

So, mining and the community are inseparable. What happens when lithium mining starts in Cornwall will be another story!

D. Tudor

The Competent Person


The SAMREC Code (2016) defines a Competent Person as one having a minimum of five years of relevant experience in the style of mineralization or type of deposit under consideration. In addition, a Competent Person must be registered with a professional organization (SACNASP, ECSA, SAGC) or a member or a fellow of a learned society (GSSA, SAIMM, IMSSA) or Recognised Professional Organisation (RPO). These bodies have enforceable disciplinary processes, including the power to suspend or expel a member.

In recent years, the role of the Competent Person has undergone scrutiny regarding the quality of work being presented and whether Competent Persons are overstating their level of relevant competency. Some of the problems identified are as follows:

  • Incorrectly claiming relevant competency in a deposit type or situation under consideration
  • Poor application of Reasonable Prospects of Eventual Economic Extraction (RPEEE) to justify Mineral Resource classification, and improper classification of Mineral Resources
  • Documentation of overly optimistic mining schedules, estimation of capital expenditure, and operating costs
  • Overly technically worded technical reports inclusive of sale pitches, unrealistic, or misleading statements;
  • Poor reporting of Environmental, Social, and Governance (ESG) issues
  • Failure to communicate risks related to mineral deposits and projects adequately and clearly
    Failure to use multidisciplinary technical specialists to improve the quality of the technical report.

Self-assessment of relevant competency is important and is also connected to ethical considerations. Competent Persons must be clearly satisfied in their own minds that they can face their peers and demonstrate competency. The investment community is seeking transparency from Competent Persons, with many calling for the inclusion of detailed CVs to demonstrate a Competent Person’s relevant experience.

The application of RPEEE can widely vary between Competent Persons. The Competent Person must consider the geoscientific knowledge and the modifying factors, both technical and economic aspects. The establishment of RPEEE demands an Initial Assessment, not simply an inventory of mineralized material above a stated cut-off grade.

The application of modifying factors in technical studies is critical. The Competent Person must ascertain that the inputs used in technical studies are appropriate and not overly optimistic. It is recommended that technical specialists assist Competent Persons in ensuring all technical inputs are appropriate and realistic, and the associated risks are highlighted. Key inputs include ramp-up schedule, development rates, estimation of mining loss and dilution (i.e. estimation of ROM grade), metallurgical recovery factors, price assumptions, operating and capital cost estimates, economic evaluation, and risk identification.

The Competent Person must employ the plain English principle to improve the readability of technical reports so as to benefit investors who lack a scientific background. Other technical reports can be written in such a manner that they resemble a prospectus rather than a technical report. In some cases, material misstatements, omissions, and misrepresentation can occur, either by accident or deliberately. The Competent Person must be diligent in investigating and reporting all material aspects and must conduct sufficient examinations to ensure conditions are as reported by the project owner or registrant. What may not be a ‘big deal’ to an owner may be material to an investor. Competent Persons must ensure they are not unduly influenced by project owners.
ESG issues have become relevant due to the increasing global awareness of human beings’ impacts on our planet. Under the SAMREC Code, ESG issues are considered fundamental contributors to Modifying Factors that play an essential role in determining RPEEE for Mineral Resources and the declaration of Mineral Reserves.

It is important to note that all projects embody risk; therefore, Competent Persons must ensure all material risks are identified and discussed. The days of a single or two-person Competent Persons team are of the past; technical reports require several specialists that should sign off on their specific areas of expertise.

Promoting continuous professional development to ensure Competent Persons are knowledgeable about current reporting trends remains paramount. This is especially important for Competent Persons on operations which may not have internal training programmes.

In the end, Competent Persons must use their professional judgement in providing adequate disclosure of all material aspects, bearing in mind that the ‘Competent Person must be clearly satisfied in their minds that they can face their peers and demonstrate competence’ (SAMREC, 2016).

Competent Persons must demonstrate a level of ethics. The author is reminded of a quote from Theodore Roosevelt – ‘Knowing what’s right doesn’t mean much unless you do what’s right’. Knowing the SAMREC Code is not enough; one must also abide by it.

S.M. Rupprecht


The value of clear communication in an increasingly complex world

Q G Reynolds 28012023As a reader of the SAIMM Journal, you might well know that the mining and metallurgical engineering industry is one of the most complex and intricate of human endeavours. This edition’s excellent set of papers particularly demonstrates that successful enterprises routinely collaborate across disciplines. Advanced technical research and development stakeholders need to interact with economic and business entities while also considering environmental sustainability, social ethics, and corporate governance. In addition to this, the industry has become truly global, with experts from a broad array of cultural and social backgrounds, sharing knowledge via the written word.

Therefore, one of the most critical skills in our industry is the ability to clearly communicate difficult concepts between different fields of expertise. When communication is done well, it can be agile and effective with minimal oversight, even in challenging time-critical workflows; without it, misunderstandings and wasted effort are the order of the day. One way to ensure that this communication is done well, is through the use of plain language principles.

The drive to adopt plain language principles is gathering momentum in many areas where large and diverse teams execute highly cross-disciplinary projects (one example is Plain language aims to improve clarity and reduce ambiguity. In particular, it can aid with the communication of information out of pockets of expertise where domain-specific jargon and terminology often obscure the core ideas. Perhaps it’s time we looked at it for our world?

Q.G. Reynolds
Pyrometallurgy Division, Mintek
Process Engineering Department, Stellenbosch University

The future of coal

H LodewijksCoal has recently gone through a revival, with demand and prices internationally at levels not seen in years. It is obviously uncertain for how long this trend will persist, but it does illustrate the pitfalls of trying to forecast demand for fossil energy in times of uncertainty. It seems clear that coal as an energy source will be largely phased out in the medium to long term, but it is clearly in demand in the short term. In the meantime, a lot of work needs to be done to complete the transition to renewable energy, and this Journal issue addresses some of the impacts of coal mining that need to be addressed in the decarbonization journey. You will find several papers dealing with coal mine wastes. This is indeed a problem that has been building for years. Tens of millions of tons of coal discard and ultrafine coal are generated each year and stored in discard facilities that require long-term care. Re-purposing and recycling are potential solutions to this ever-growing problem and perhaps the investigations described in this Journal issue will lead to progress in this field. Some of these projects have been or are being funded by Coaltech in the realization by Coaltech members that a just transition requires innovative and sustainable solutions to mining impacts that have been generated over decades.

H. Lodewijks
Coaltech Research Association

The Potential of the Young

P Pistorius 14082022This volume is similar to previous Student Editions in that it covers a range of diverse topics, from the determination of project readiness in a mining house to the welding behaviour of ferritic stainless steels used to fabricate automotive exhaust systems. There is also significant diversity in the experimental techniques used, and the application of probability calculations is particularly noteworthy in several papers. All this illustrates the breadth, depth, and vitality of the next generation starting to contribute to the activities of the various SAIMM technical communities represented by this Journal. It is worthwhile to remember that these papers have been through the same review process as other papers submitted to the Journal.

The present Student Edition had me wondering where the careers of our students showcasing their work here will take them. How many will return to their respective topics discussed in this edition during their careers, and in what way? What other reunions might our students encounter with previous assignments and experiences they embarked on as their careers progress? These reunions between the past and the present could be unexpected and intriguing. I remembered a few examples from my own career.

My first job, in the mid-eighties, was in a now-defunct heavy foundry that produced mining equipment, such as winders, ball mills, crushers, and a range of dragline components. One of the flagship product lines was winders for the gold and platinum mining industry. Recently, 35 years after leaving the foundry, I helped to evaluate one of those winders. I immediately recognized the imprints from the mould assembly and the indifferent surface finish inherent to the Portland cement-based sand system used in that foundry. The winder did not show any evidence of cracking and was probably good for another three of four decades of service. That the component was completely overdesigned will probably stand the owner in good stead. It is almost counterintuitive, but the scarcity of sophisticated finite-element analyses techniques when this winder was designed will help to ensure a long service life.

Some years ago, I took a group of third-year students on a visit to a power station that was still under construction. We were shown around by the commissioning personnel. It was to me, probably more than to the students, a fascinating visit, with the boilers in various states of construction. We looked down on a low-pressure turbine that was shipped from the supplier as a complete unit and had been lowered into position a few days before our visit. While looking at the casing, I realized that I remembered the patternmaker’s drawings for this component. There was an incident, many decades ago, when a skip filled with chills (small steel inserts used to affect the solidification front) dropped its load through the pattern, destroying months of patternmakers’ work.

I recently helped a mechanical engineer to review the repair procedures for a very large type-316L stainless-steel tank. On working through the documentation, I discovered that the tank was fabricated by a company in Gauteng that I had visited when I started to expand the scope of welding-related activities in the Department of Materials Science and Metallurgical Engineering at the University of Pretoria. The founder and owner of the fabrication company had a very clear and useful perspective on the role that a young engineer should play in such companies: essentially, a young engineer should not spend too much time in the office, get onto the shop floor, and get some holes in his or her overalls. As far as I know, the company has disappeared, but the stainless-steel tank was still in good condition, and it was well worth repairing the few small defects that had developed in over twenty years’ service.
It would be unwise to speculate what circuitous routes the careers of the students represented in these ten papers will follow. The world, Southern Africa, and the mining and metallurgical industries are rapidly evolving, and in this dynamic environment, it is unlikely that most of these papers present first steps in a highly specialized career in the respective fields of knowledge for these students. Rather, it is likely that some of these students will again be acquainted with their work in a roundabout way, possibly similarly to what I have encountered.

From a different perspective, the students’ papers also embody and demonstrate two important skills, namely the ability to absorb and apply new knowledge and the ability to communicate it. These durable skills are only developed when the quality of investigative work and quality of presentation of the results (in this case, as a journal paper) are high. Finally, it is worthwhile to stay somewhat humble, and remember that some students may take the material that they are taught much further than their professors can ever anticipate.

P. Pistorius
University of Pretoria, South Africa

Battery metals – The Next Big Thing?

Mining and metallurgy have been linked throughout time to the development of the human race. You can argue that the First Big Thing was precious metals. Gold and silver have been symbols of wealth since at least Egyptian times. Then the Bronze Age signalled the Second Big Thing, base metals. This started initially with copper and tin to make bronze. Lead was also used during the Bronze Age. Then after this, the Iron Age brought on the Third Big Thing – ferrous metals. Initially this involved only iron. Over time platinum group metals were included with the precious metals and zinc, nickel, and aluminium with the base metals. Ferrous metals have certainly expanded the most via a vast array of alloys, notably steel and stainless steel.

So, what is the Next Big Thing? It has to be battery metals. After the interruption caused by the Covid-19 pandemic, the world has become engulfed by a green revolution. The most prominent aspect of this is rechargeable batteries, especially those for electric vehicles. These batteries require mainly lithium, nickel, cobalt, and manganese. Nickel and manganese were well established within the ferrous metals sector but lithium and cobalt were previously considered minor metals. Now, of course, lithium in particular is viewed as the ’flavour of the month’. Skyrocketing prices of lithium and cobalt in particular have caused an exploration boom, with geologists all over the world looking for lithium and cobalt, amongst many other metals.

From a metallurgical perspective battery metals bring new challenges. All battery metals have to be supplied as very pure salts, usually a minimum of 99.9%, with lithium in the form of carbonate or hydroxide and the others in the form of sulphates. This has resulted in considerable process development research to meet the ever-increasing purity requirements.

The demand for battery metals has had, and will continue to have, an enormous impact on the global mining industry. Geologists, mining engineers, and metallurgists will continue to face greater challenges in the discovery, mining, and processing of battery metals. It is also fair to say that battery metals have really highlighted the contribution of the mining industry to global economic development. And long may this continue!