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By P. W. J. van Rensburg

COLLOQUIUM AND GENERAL MEETING A General Meeting and Colloquium on comminution was held on March 13th, 1974, at Kelvin House, Johannesburg. Mr P. W. J. van Rensburg (President) was in the chair. The Colloquium was attended by 140 delegates and was opened by the President at 9.15 a.m. MINUTES The minutes of the general meeting held on November 14th, 1973, as published in the December issue of the Journal, were confirmed.

Jan 5, 1974

By M. Krasowska, W. Skinner, R. K. Asamoah

Understanding chemical interactions at solid-liquid interfaces have played a pivotal role in improving mineral flotation performance, increasing the rate of mineral crystallisation and profitable leaching of valued minerals and metals. This paper highlights gold leaching with links to surface and interfacial chemical processes occurring, and opportunities to maximise extraction while reducing usage of more recent scarce resources. From the review, there is a significant link between surface and interfacial processes and gold leaching performance. Evidently, gold leaching kinetics could be increased by changing leaching conditions, including manipulating the surface and interfacial interactions. Control of surface and interfaces during gold extraction could enhance rapid, smarter gold extraction and mitigate formation of passivation layers. Keywords: Surface and interfaces, refractory ores and concentrates, gold leaching, reaction mechanism and kinetics

Jan 1, 2020

By C. M. Sellars, W. E. Stumpf

SYNOPSIS The effects of concurrent recovery, prior creep deformation and concurrent high temperature fatigue on the coarsening of some carbides in steels have been studied. It was found that concurrent recovery enhances the coarsening rate by orders of magnitude and prior creep deformation causes an enhancement of about two times. Finally, concurrent fatigue causes an initial greatly enhanced coarsening rate but after prolonged cycling dissolution of the carbides occurs.

COUNCIL The following served on Council during the year under review: Office bearers: Prof D. D. Howat (President), Dr J. P. Hugo and P. W. J. van Rensburg (Vice-Presidents), V. C. Robinson (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Ordinary Members of Council: H. P. Carlisle, R. C. Espley-Jones, G. H. Grange, Dr D. I. Legge, W. W. Malan, Prof R. P. Plewman, Dr R. E. Robinson, Dr M. D. G. Salamon, L. W. P. van den Bosch and P. A. von Wielligh. Branch Chairmen: A. Bain (Witbank-Middelburg Branch), J. M. Meyer (O.F.S. Branch). Past Presidents serving on Council: R. J. Adamson, M. Barcza, H. Britten, H. E. Cross, J. K. E. Douglas, R. C. J. Goode, P. Lambooy, Prof J. de V. Lambrechts, Dr J. T. McIntyre, J. F. Reid and H. Simon (until March 1972). Ten Council meetings were held during the year with an average attendance of nineteen, and the standing committees held 27 meetings. FINANCE The annual accounts which are attached to this report show an excess of income over expenditure of R21 519. It is very gratifying to be able to report that Council's efforts to stop the depletion of our accumulated funds are meeting with success. The most important contributors to our surplus this year are symposia and colloquia, sales of publications, Company Affiliate subscriptions and the profit on the journal. While we do not expect continued profits from all these sources in the future we do feel that we are now in the process of accumulating a substantial financial foundation. This will give the Council the necessary confidence to initiate the new developments in the activities of the Institute which are now under consideration. The decision to create a new grade of membership, Company Affiliate, is dealt with elsewhere in this report. There has been a generous initial response from companies and this is the cornerstone of our improved financial expectations. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of R91 and the total fund was, therefore, increased by this amount to R4 502. The balance sheet shows that the market value of quoted shares and debentures increased during the year from R9 160 to RH 331, which is R2 134 in excess of the book value. Accumulated funds now amount to RH 529 compared with R23 010 a year ago. MEMBERSHIP Sixteen Fellows, twenty Members, six Graduates, nine Associates, twelve Students and twenty-four Company Affiliates were elected during the year. One Member and two Associates were reinstated. Twelve members were admitted to retired membership. Transfers: Member to Fellow, three. Graduate to Member, seven Associate to Fellow, one. Student to Member, one. Student to Graduate, four. Student to Fellow, one. Your Council records with deep regret the death during the year of the following: Dr A. J. Orenstein (Honorary Life Fellow), R. A. Cooper, R. J. Spargo, H. Simon and F. Meyer (Life Fellows), S. D. Loxton, W. P. Arnold, G. C. Needham, W. G. Pyne-Mercier, J. Innes and O. T. Wright (Fellows), E. P. Mennell and O. B. Prentis (Members), J. Brits (Associate). After careful consideration of all the implications it was decided during the year to create a new grade of membership to be known as Company Affiliate, in order that there might be a formal and permanent channel for companies to contribute to the important work of the Institute. As recorded above, 24 companies had joined by the end of the year and many further applications have been received since. We extend a hearty welcome to all our new members. A comparative statement of membership as at 30th June, 1972, and the end of the previous year is shown in the following tabulation:-

By K. H. Zhang, Y. P. Gao, J. Q. Zhao, Q. Li, J. C. Ma

Compared with sinusoidal oscillation, non-sinusoidal oscillation enhances the ability to control waveform and meets different oscillation requirements by adding an independent parameter, which is the key technology for high-efficiency continuous casting. A new waveform of mould non-sinusoidal oscillation is proposed in this paper, that is, a velocity waveform that is composed only of straight lines and parabolas, which not only has good dynamic characteristics, but also further enhances the feature of non-sinusoidal oscillation. Compared with sinusoidal oscillation, the negative strip time is reduced by 15.9%, the maximum negative strip velocity difference is increased by 38.3%, and the maximum positive strip velocity difference is decreased by 27.8%. The formulas of oscillation process parameters can be clearly deduced, and the isoplethic curves of oscillation process parameters when multi-parameter simultaneously changes are drawn. The negative strip time decreases as the modification ratio, frequency, and casting speed increase, but increases as stroke increases. In order to maintain the stability of negative strip time, an oscillation synchronous control model for optimising oscillation basic parameters was developed. Through practical application, the mean oscillation mark depths decreased by 10.1 μm and the flux consumption is increased from 0.37 kg/t to 0.45 kg/t in the non-sinusoidal oscillation model, which meets the requirements of normal production.

Oct 24, 2025

By F. S. Hoseinian, D. Deglon, L. leal Filho, M. Safari, T. C. Souza Pinto

This paper investigates the effect of chemical and physical operational parameters on the reverse flotation of Timbopeba itabirite iron ore in a pilot-scale pneumatic flotation cell. Operational parameters include collector and depressant dosages, feed rate, superficial gas velocity and solids concentration. Results show that increasing collector dosage results in an increase in quartz recovery, particularly for the coarser quartz where recovery increases by nearly 30%. Increasing depressant dosage results in a decrease in both quartz recovery and hematite loss, for the coarser hematite particles. Increasing the feed rate has no effect on quartz recovery or hematite loss, suggesting that the pneumatic flotation cell is not residence time constrained. Increasing the superficial gas velocity results in an increase in quartz recovery to an optimum at a Jg of around 0.6 cm/s after which it decreases significantly, particularly for the coarser particles where recovery decreases by as much as 50%. Decreasing the solids concentration does not affect quartz recovery but results in significant decreases in hematite loss. Here, fine and coarse hematite loss decreases from around 25% to 12% and 10% to 2% respectively. Superficial gas velocity and solids concentration are operating parameters which have the largest effect on the flotation performance of the pneumatic flotation cell. Results suggest that this flotation cell should be operated at relatively low superficial gas velocities and solids concentrations. However, these are pilot-scale findings and would need to be tested at an industrial-scale where different operating conditions may be optimal. Keywords: Operational parameters, reverse froth flotation; entrainment; iron ore

Jan 1, 2020

By P. Gauvillé

The key driver for choosing a circulating fluidized bed (CFB) boiler is the ability to burn a wide range of fuels with highly efficient combustion while meeting low emission requirements. Reduced sorbent and water consumption compared with pulverized coal (PC) plants and the ability to deal with corrosive fuel constituents while still meeting local regulations make a CFB boiler-based power plant particularly attractive. CFB-based power generation is particularly relevant in coal mining areas. During mining, a portion of the roof and floor material may be extracted along with the coal seam in order to create adequate working height for the equipment and miners. Therefore, run-of-mine coal which comes directly from the mine contains impurities. The raw coal can undergo a washing or screening process in order to improve its quality by reducing the ash content in the fuel in order to sell it on the export market or to comply with domestic customer requirements. The coal discarded from the washing process usually has a high ash content and difficult mechanical properties resulting from the initial properties, the mining, and the coal cleaning processes. It can contain a large volume of stones or can be very fine as a result of the washing treatment. To create value from burning this discarded coal, the boiler supplier has to meet several technical challenges in developing the appropriate design. This paper highlights the performance achieved with Alstom's CFB boilers developed for power generation over the last two decades to extract value from discarded coals. Emile Huchet Power Plant is the first 125 MWe CFB unit developed for burning coal slurries (called schlamms in France). The Emile Huchet discarded coal fuel is a very fine high-ash residue with an average particle diameter by mass (d50) of around 80 µm as received from the washing plant. The paper describes the performances and the basic design of the CFB boiler to manage such a fine fuel. The performances of two other CFBs of approximately 300 MWe output in operation in the USA and PR China are also mentioned to demonstrate the capability of this technology to burn either low-volatile bituminous or anthracite waste coals. The significant issues experienced during commissioning are reported, and the conceptual choices for burning such fuels are mentioned.

Jan 1, 2012

By SAIMM SAIMM

To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements of The South African Institute of Mining and Metallurgy set out on pages 575 to 586 for the year ended 30 June 2005. These financial statements are the responsibility of the Institute?s Council. Our responsibility is to express an opinion on these financial statements based on our audit. Scope We have conducted our audit in accordance with International Standards on Auditing. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes: examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion. Audit opinion In our opinion, the financial statements fairly present, in all material respects, the financial position of the Institute at 30 June 2005 and the results of its operations and cash flows for the year then ended in accordance with South African Statements of Generally Accepted Accounting Practice.

Jan 1, 2005

By V. Moodley

Strict implementation of International Standards for representative sampling of coal is difficult for routine monitoring, due to time, technical, and economic constraints. A large percentage of the total sampling variance arises from errors accumulated during the earliest stages of sample collection. Modified procedures on the precision of the final result leads to controversies between the sellers and customers for coal. Manual collection of coal samples violates the principle of correct sampling, that all fragments must have an equiprobable chance of being in the sample. In addition, manual size reduction of large numbers of samples is time consuming and involves human errors. A coal quality management procedure in alignment with the relevant ISO standards that describes the sampling protocol has been implemented, and current sampling and laboratory analysis of coal from base load mines (mines situated at the mouth of the power station) are well established. For import coal, sampling is performed during unloading by auto-mechanical sampling (AMS). Due to logistical and safety issues associated with multiple suppliers, Eskom opted for the coal to be sampled at source on a pre-certification basis. Online analysers provide a fast, accurate, real-time method of determining the total moisture and elemental composition of coal and is important to the coal industry for pricing, quality control, and reduction of SO2 emissions. Elemental analyses include S, Si, Al, Fe, Ca, Na, Mg, Mn, Ti, K and Cl. Measurement of S is dictated by the control of SO2 emissions from coal-fired power plants. Elements such as Na and Cl have adverse effects on boilers, causing fouling and slagging. Available online elemental analyser technologies include prompt gamma neutron activation analyses (PGNAA), recommended for major element determination, and pulsed fast and thermal neutron analysis(PFTNA), that is capable of measuring the major and minor chemical elements contained in coal. These systems utilize nuclear reactions to produce characteristic gamma rays that are used for identifying various chemical elements. By acquiring the gamma rays in three different time windows, there is a significant reduction of the background as compared with the spectra taken with a radio isotopic source.

Jan 1, 2009

Ladies and gentlemen, it is a privilege to be able personally to welcome you to the opening of this Symposium. It is particularly pleasant to be able to extend a warm South African welcome to al our visitors from foreign shores. We trust you will enjoy your stay in our country. It is a singular honour for me to be present here today, and to have been asked to open this international Symposium. MINING IN SOUTH AFRICA Mining is the single most important contributor to this country's foreign-exchange earnings. Minerals and processed mineral products together account for about 70 per cent of South Africa's total foreign exchange earnings. The mining sector employs in excess of 670 000 people, and is one of the largest employers in the country. The construction and development of cities and towns like Johannesburg, Welkom, Orkney, Springs, Benoni, Witbank, and Klerksdorp is a direct result of the contributions of the mining industry to economic activity in these areas, as well as of the multiplier effect of secondary industries.

Jan 1, 1993

By H. Rosenberg

Haldor Topsoe A/S has developed its WSA technology to meet the demand in the market for a simple and reliable process that converts sulphurous emissions from off-gasses into high-grade sulphuric acid. With more than 50 references in 25 countries, the WSA technology has proven its ability to generate acid at 98% concentration, efficiently and economically. The wet gas sulphuric acid (WSA) technology treats the furnace off-gas directly from upstream gas cleaning plants. No further drying is required, since the humidity present in the off-gas is used to hydrate the SO3generated in the converter and produce sulphuric acid. The heat generated during the oxidation, hydration and condensation processes is principally reused in the process to preheat the off-gas to the required temperature level, and also to generate high pressure superheated steam for process use. This advantage of steam production, coupled with lower water and power consumption requirements, is particularly important in the African production environment. Having fewer process components than conventional acid plants, the WSA technology is a simple and compact operation, which makes it easier to retrofit into an existing smelter plant. Further, the WSA technology simultaneously offers the possibility to treat multiple gas streams arising within the production facility due to superior flexibility in terms of SO2concentration and turndown ratio.

Jan 1, 2006

By M. L. Mahlatji

Mechanical alloying of an equiatomic mixture of crystalline Ti and Pt elemental powders in a high-energy ball mill formed an amorphous alloy by solid-state reactions. Mechanical alloying was carried out in an argon atmosphere at a rotation speed of 1200 r/min and a 20:1 ball-to-powder weight ratio, for time intervals of 4 to 40 hours. At an intermediate stage of mechanical alloying, scanning electron microscopy showed the formation of characteristic layered structures of inhomogeneous composition within the powder particles. X-ray diffraction analysis showed the gradual disappearance of crystalline Bragg peaks and the emergence of broad amorphous maxima as milling progressed. The amorphization process was completed after 8?12 hours. The amorphous state of the product indicated that temperatures during processing did not exceed the crystallization temperature of the alloy.

Jan 1, 2014

The AK6 kimberlite is situated 25 km south of the Debswana Orapa Mine in Botswana and was discovered by De Beers geologists in 1969 during the follow-up of geophysical targets in the Orapa area. The kimberlite was not extensively pursued at the time as the initial bulk sampling indicated it to be of limited size and low grade, factors largely contributed to by the basalt breccia capping. Completion of high resolution integrated geophysical techniques and drill bulk sampling to depth recovered 97 tons of kimberlite during 2003 and 2004, which led to the increased size and grade estimates. Bulk sampling by Large Diameter Drilling (LDD, 23 inch diameter) commenced in 2005; 13 holes were drilled to a cumulative depth of 3,699 m and 689 carats of diamonds were recovered. In July 2006 the De Beers Mineral Resource Classification Committee classified these Phase I LOO results at a High Inferred level with an average grade of 24 carats per hundred tonnes (cpht) at a bottom cut-off of +1 mm, and a modeled average diamond value of 150 dollars per carat. A second phase of LDO drilling was initiated in 2006, and bulk sampling by trenching commenced in 2007 in order to deliver a resource estimate at indicated level. An Indicated Resource of 11.1 million carats at an average grade of 22 cpht was declared for the deposit mining lease application lodged in 2007.

Jan 1, 2010

By R. F. Botha

I want to thank you for inviting me to deliver this, the closing address at the final plenary session of the 15th Congress of the Council of Mining and Metalurgical Institutions. Your Council has an impressive title, and justly so. Consider the expertise, the skill, the capacity, the achievement, that is gathered together here in this room this afternoon.

Jan 1, 1994

The first neutrinos in nature ever detected by man were "caught" in a unique laboratory some 3 km (over 2 miles) underground in one of the world's deepest mine shafts at East Rand Proprietary Mines (ERPM), Boksburg. Only 100 m from where gold is being mined from the rock face a small team of South African and American physicists work on one of the most fascinating and important fundamental research projects that is currently exciting the imagination of the scientific world. Neutrinos are sub-atomic particles just as are protons, neutrons and electrons, but they are unique in that they have neither electric charge nor mass. Cosmic neutrinos travel at the speed of light and penetrate stars and planets. Even a million kilometres of solid lead would not provide a satisfactory shield against them. Stars are believed to "burn" by means of nuclear reactions which produce enormous fluxes of neutrinos. The sun, for example, illuminates the earth with visible light, but also bathes it with neutrinos. After World War II, two American physicists, Profs Frederick Reines and Clyde Cowan, experimenting at a large nuclear reactor, succeeded in obtaining direct evidence of the existence of the laboratory-produced neutrino. It then became very important to establish whether neutrinos also existed in nature. This knowledge would lead to a greater understanding of the forces of nuclear physics, of the behaviour of nuclear particles and, indeed, is also relevant to astrophysics. From the start it was clear that the search for "natural" neutrinos would be difficult. Questions which arose were- * how could they be traced if they were without mass or electric charge? * how could other nuclear particles be screened off? * could these not be wrongly detected, or even prevent accurate detection of neutrinos? Neutrinos were known to be produced along with charged particles, by the reaction of primary cosmic rays with the constituents of the atmosphere. It was also known that when the neutrinos collided with matter, they themselves produced the same type of charged particle which could be detected if the unwanted charged particles from the atmosphere could be screened off. What was needed, therefore, was a laboratory where the particles produced in the atmosphere could be screened out, yet which would receive and detect the particles produced by the neutrons' collision with the matter (solid rock) in the vicinity of the laboratory. This meant that scientists either had to build a laboratory with an enormously thick lead shield for their detection work. . . or they could go as near as possible to the centre of the earth where only charged nuclear particles of the very highest energies could penetrate. ERPM was clearly the most suitable place in the world where so effective a "neutrino trap" could be set. Under more than 3 000 m of solid rock the apparatus for detecting neutrinos is well shielded against unwanted nuclear particles produced in the cosmic radiation which can reach the laboratory only in a steeply vertical trajectory. Other particles are easily stopped by the great thickness of rock. The air-conditioned laboratory is at one end of a 150 m long tunnel, 2,5 m high and wide, blasted from the rock. The electronic recording equipment is housed here, while the rest of the tunnel is filled with the detection system. When a charged particle passes through a detector element, it produces a minute flash of light which is recorded and which triggers a flash-tube array. This then defines the trajectory of the charged particle, which is also recorded on film for analysis. So far 82 neutrinos have been detected, 50 at the present level and 32 at a higher level, and the findings have borne out the physicists' theoretical expectations. In this joint project Profs Reines, J. P. F. Sellschop, Director of the Witwatersrand University's Nuclear Research Unit and M. F. Crouch of the Case-Western Reserve University of Ohio are the Chief Investigators. This unique endeavour has been made possible by financial support from the US Atomic Energy Commission, the University of the Witwatersrand and the Chamber of Mines of South Africa, as well as by the cooperation of the management and men of ERPM.

By T. Vincent, J. Steele, C. Debrunner, M. Whitehorn

This paper presents current work on the development and use of stereovision for underground mining. Information on the calibration of the cameras and the feature-matching algorithm are presented. This system uses an intensity-based approach that evaluated correspondences along the epipolar line. Once features have been identified and their distance from the cameras computed, a three-dimensional map of the muck pile is developed. The approach used here uses a ray-tracing algorithm. This approach provides an uncertainty measure along with the elevation. A discussion of the use of this modelling information in the control of the LHD is included. Keywords: Robotics, automation, LHD, underground mining, vision sensing, task automation, tele-operation

Sep 1, 2001

By C. C. E. Pretorius, V. M. Mathoho, A. van Zyl, R. J. Mostert

The in-service degradation of the mechanical properties of steel components through the damage mechanism of high temperature hydrogen attack (HTHA), is a topic of concern in the refining and green hydrogen industry. This damage mechanism occurs in susceptible steels operating in environments at high temperatures and hydrogen pressures. The current investigation deals with the indirect monitoring of mechanical degradation via tracking of the swelling strain in affected structures. An autoclave with an AISI 316 shell was utilized to simulate accelerated HTHA damage at 550 °C and 46 bar for exposure times ranging from zero to 700 hours. The progress of the HTHA damage was tracked using encapsulated high-temperature strain gauges. The correlation between the swelling strain and mechanical property degradation was studied to develop a methodology for the continuous monitoring of embrittlement. The tensile sample orientation of the carbon steel plate was included as a variable, i.e., samples parallel, transverse, or perpendicular to the plate rolling direction were included, since it has been shown that the sample orientation influences the HTHA damage features. For the through-thickness orientation, and upon exceeding a threshold value of exposure time, all tensile properties were severely degraded, with values in the order of a 90 per cent reduction being observed. It was found that the degradation of carbon steel mechanical properties can be correlated to the swelling strain measured during exposure. The critical point for mechanical property degradation in the plate through-thickness orientation, whereafter a severe decrease in the ductility of the material occurs, was found to be in the order of 1% of the total swelling strain measured during exposure, equivalent to 65 microstrain. This threshold was found to be significantly lower than that expected from the literature, where limits of 400 to 1000 microstrain were postulated.

Nov 27, 2024

The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal. All papers must meet the standards set by the Council of the Institute, and for this purpose all papers are referred to at least two referees appointed by Council. STANDARDS FOR ACCEPTANCE To merit consideration papers should conform to the high standards which have been established for publication over many years. Papers on research should contain matter that is new, interpretations that are novel or of new significance and conclusions that cast a fresh light on old ideas. Descriptive papers should not be a repetition of well-known practices or ideas but should incorporate developments which would be of real interest to technical men and of benefit to the mining and metallurgical Industry. In some cases a well prepared review paper can be of value, and will be considered for publication. All papers and particularly research papers, no matter how technical the subject, should be written with the average reader of the Journal in mind, to ensure wide interest. The amount of textbook material included in a contribution should be the minimum essential to the argument. The length of a paper is not the criterion of its worth and it should be as brief and concise as possible, consistent with the lucid presentation of the subject. Only in very exceptional circumstances should a paper exceed 15 pages of the Journal (15 000 words, if there are no tables or diagrams). Six to ten pages is more normal. NOTE: Papers in the Journal are printed in 10 point type, which is larger than the 8 point type used on this page. For special publications Council may decide on page sizes smaller than A4 used for this Journal. The text should be typewritten, double-spaced, on one side only on A4 size paper, leaving a left-hand margin of 4 cm, and should be submitted in duplicate to facilitate the work of the referees and editors. LAYOUT AND STYLE Orthodox sequence Title and author's name, with author's degrees, titles, position. Synopsis. Index, only if paper is long and involved Introduction, including a brief statement of conclusions. Development of the main substance. Conclusions. in more detail. Acknowledgements. References. Title: This should be as brief as possible, yet give a good idea of the subject and character of the paper. Style: Writing should conform to certain prescribed standards. The Institute is guided in its requirements by: Collins, F. H., Authors & Printers' Dictionary-Oxford University Press. Hart, H. Rules for Compositors and Readers. Humphrey Milford (familiarly known as the Oxford Rules). Fowler, H. W. & F. G. The King's English-Oxford University Press. General: A few well selected diagrams and illustrations are often more pertinent that an amorphous mass of text. Over-statement and dogmatism are jarring and have no place in technical writing. Avoid the use of the first person, be objective and do not include irrelevant or extraneous matter. Avoid unnecessary use of capitals and hyphens, while punctuation should be used sparingly and be governed by the needs of sense and diction. Sentences should be short, uninvolved and unambiguous. Paragraphs should also be short and serve to separate basic ideas into compact groups. Quotation marks should be of the 'single' type for quotations and "double" for quoted matter within quotations. Interpretations in the text should be marked off by parentheses ( ), whereas brackets [ ] are employed to enclose explanatory matter in the text. Words to be printed in italics should be underlined singly. For small capitals they are to be underlined DOUBLY and for large capitals TREBLY. If there is any problem in producing formulae accurately by typewriter they should be inserted by handwriting in ink in the copy forwarded by authors. Abbreviations and symbols are laid down in British Standard 1991. Abbreviations are the same for the singular and plural, e.g. cm for centimetre and centimetres, kg for kilogram and kilograms. Percentages are written in the text as per cent; the symbol % is restricted to tables. A full stop after an abbreviation is only used if there is likely to be confusion of meaning. Metric System: The Systeme International d'Unites (S.I.) is to be used for expressing quantities. This is a coherent system of metric units derived from six basic units (metre, kilogramme, second, ampere, kelvin, and candela), from which are derived all other units, e.g. the unit of force is the newton (N) for kilogramme metre per second per second (kg m/s2). Always use the standard metric abbreviations. Commas must not be used for separating groups of digits. For ease of reading digits should be grouped in threes counting from the decimal point towards the left and the right. Illustrations: Drawings and diagrams are to be in black India ink and should be about 18 cm wide. When submitting graphical representations avoid a fine grid if possible. Curves should be in heavy line to stand out. Lettering too should be bold as a reduction in size is often involved in the printing process. (A single column is 8.5 cm wide.) Numbering of tables should be in Roman numerals: I, 11, etc. and figures in Arabic numerals: Fig. 1, Fig. 2, etc. (Always use the abbreviation for figure.) Photographs should be black and white glossy prints. As a guide to the printer the author should indicate by means of notes in the typescript where tables and figures, etc. are to appear in the text. Paragraphs: A decimal system of numbering paragraphs may be used when the paper is long and complicated and there is a need for frequent reference to other parts of the paper. Proof correction: Galley proofs are sent to authors for the correction of printers' errors and not for the purpose of making alterations and additions which may be expensive. Should an author make alterations which are considered excessive, he may be required to pay for them. Standard symbols as laid down in British Standard 1219C should be used. SYNOPSIS It is most important that the synopsis should provide a clear outline of the contents of the paper, the results obtained and the author's conclusions. It should be written concisely and in normal rather than abbreviated English and should not exceed 250 words. While the emphasis is on brevity this should not be laboured to the extent of leaving out important matter or impairing intelligibility. Summaries simplify the task of abstractors and therefore should present a balanced and complete picture. It is preferable to use standard rather than proprietary terms. FOOTNOTES AND REFERENCES Footnotes should be used only when they are indispensable. In the typescript they should appear immediately below the line to which they refer and not at the foot of the page. References should be indicated by super-script, thus. . .1 . . .2. Do not use the word Bibliography. When authors cite publications of other societies or technical and trade journals, titles should be abbreviated in accordance with the standards adopted by this Journal. GENERAL The Council will consider the publication of technical notes taking up to three pages (maximum 3 000 words). Written contributions are invited to the discussion of all papers published in the Journal. The editors, however, are empowered by the Council to edit all contributions. Once a paper or a note has been submitted to the Institute, that document becomes the property of the Institute, which then holds the copyright when it is published. The Institute as a body is, however, not responsible for the statements made or opinions expressed in any of its publications. Reproduction from the Journal is permitted provided there is full acknowledgement of the source. These points should be borne in mind by authors who may submit their work to other organizations as well as to the Institute. P.W.J.vR.

By E. Govender-Opitz, L. Lelia

The South African mining industry plays a significant role in the economy of the country. Nonetheless, the negative impacts on the environment continue to prevail. In regions where mining exists in proximity to communities, mining activities have led to the disruption of modality. Rural communities are mostly affected as they depend on land use for agriculture to sustain their livelihoods. The conversion of land for mining activities often leaves the communities vulnerable when mines close because of the limited life span of mines. An ongoing discourse focuses on how the mining industry can contribute to sustainable development of the communities in which they operate. Post-mining transformation offers an approach for the mining companies to contribute to sustainable livelihoods post-mine closure by strengthening rural-urban linkages, which ensures inclusive development of both rural and urban areas. The paper employs a case study approach to Richards Bay Minerals and the adjacent rural communities of Sokhulu and Mbonambi. It sets out to understand the post-mining transformation employed by RBM and explore the rural-urban linkages that manifest as a result. Findings show that sand dune rehabilitation employed by RBM is successful in restoring soil fertility and establishing the natural ecosystem. The casuarina planted to rehabilitate the dunes is used to spur an alternative charcoal industry post-closure. The main rural-urban linkages that manifest are flows of people due to job opportunities and flows of goods from the sale of charcoal produced. However, there is a lack of communication and lack of authority to ensure responsible management of the casuarina plantation and equitable sharing of benefits. The paper recommends that other post-mining transformation strategies such as eco-tourism should be explored and that the government, at both national and local level, the community and the mine should be involved to ensure overall success and sustainability of the strategy. Keywords Post-mining transformation, rural-urban linkages, alternative land use

Jan 1, 2020

By I. Cameron, S. Ramjee, A. M. Garbers-Craig

The cause of reduced workability and increased ageing of a blast furnace taphole clay was examined. The investigated taphole clay contained 60 mass% alumina, with phenol-formaldehyde resole resin and liquid pitch serving as the binder system. The workability and Marshall extrusion pressure of the as-manufactured clay samples were evaluated to assess the extent of ageing of the clay. The wettability of all the raw materials was investigated to confirm compatibility between the dry raw materials and both the resin and liquid pitch, while the dry raw materials were analysed using XRF, XRD, and SEM-EDS. The characterisation of the resin and liquid pitch, as well as an analysis of their interaction, was performed using viscosity measurements, Fouriertransform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The analyses confirmed a chemical interaction between the resole resin and liquid pitch, where the chemical structure of the resole resin changed when mixed with pitch, preventing the typical curing behaviour of the resin. Upon ageing of the resin-pitch mixtures, the resin underwent premature cross-linking, causing the curing process to initiate at lower temperatures, i.e., earlier onset of curing. This premature cross-linking was likely due to secondary amines present in the liquid pitch, which acted as a catalyst for the curing process of the resin. This reduction in curing temperature after ageing was confirmed by an increase in binder viscosity, which was identified as the primary cause of reduced workability, accelerated ageing, and increased Marshall extrusion pressure of the taphole clay.

Jul 23, 2025