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By C. G. Schmidt, N. W. Hanf

Many of the pyrite concentrates produced at South African gold and uranium mines contain economically significant amounts of nickel, copper, and cobalt, apart from gold and uranium. In some cases these concentrates are leached for uranium, followed by roasting and cyanidation of the calcine for the extraction of the gold. Even if their intrinsic value is excluded, the presence of appreciable amounts of base metals can lead to excessive consumption of cyanide and zinc in the conventional process for the recovery of gold from calcines. The extent to which base metals, particularly cyanocides in the calcine, can be made soluble in water or in dilute acid by variation of the pyrite roasting conditions was investigated. An important finding of the investigation was that the conditions producing favourable base-metal sulphation (and hence solubility in water) also produced good sulphation of the uranium values that had not been extracted in a conventional leach of the original pyrite. Thus, if the pyrite is subjected to a sulphating roast followed by quenching in water (or dilute acid), it should be possible for the uranium to be extracted in improved yield. The need for leaching of the pyrite would therefore fall away. It was noted that sulphation roasting also resulted in improved gold extractions when the calcine was subsequently subjected to conventional cyanide-extraction procedures. From well-sulphated calcine, the dissolution of base metals and uranium appeared to be fairly independent of leaching pH, time, and temperature. On an inadequately sulphated calcine, Iow pH values during leaching gave increased extraction of copper and uranium but did not have a significant effect on the dissolution of nickel and cobalt. The extraction of uranium increased with increasing leaching time and temperature, while only longer times at a Iow pH value markedly improved the extraction of copper. The extraction of cobalt was fairly independent of leaching time and temperature, but the results were insufficient for a conclusive evaluation to be made of their effects on the dissolution of nickel. A cursory economic assessment 'indicated that sulphation roasting applied to the pyrites investigated is likely to be very profitable.

Jan 1, 1979

By R. Pretorius, N. Mautsa

In a cobalt precipitation plant, phosphoric acid is used to eliminate excess uranium from the pregnant leach solution, resulting in a cobalt hydroxide product that has little uranium contamination. However, the amount of phosphoric acid added must be monitored and controlled to avoid financial and sustainability impacts and to prevent negative impacts on the final product quality. One possible solution to this problem is the use of online residual phosphorus measurement techniques to regulate the addition. By continuously monitoring the residual phosphorus levels in the solution, the plant can adjust dosing in real time to maintain the target residual phosphorus level. As a result, the cobalt precipitation plant can improve phosphorus level control, lowering the risk of overdosing, and ensuring consistent product quality. This approach can also improve process efficiency, reduce operational costs, and have a positive environmental impact

Jan 1, 2023

By M. Z. Emad, S. Raza, K. Jalil, M. A. Raza, M. U. Khan, S. A. Saki

Dimension stone mining is Increasing because of growing demand from the building and construction industries. Diamond wire saw cutting is a popular dimension stone mining technique around the world. Estimation of the production cost for this method is critical for these operations. n this research a production cost model was developed for the mining of granite using a diamond wire saw. Cost and production data were collected from a granitic dolerite operation in Pakistan for a 4.5-year period, and analysed to identify the cost components. Fuel (34%), labour (15%), consumables (40%), and maintenance (5%) were found to be the four major cost components in this operation. A regression-based dimension stone production cost model incorporating statistically significant variables was developed. The data presented a strong correlation of production cost with fuel, labour, and consumables costs. Finally, a production cost model based on the consumption cost of diamond wire is presented. The model was verified using actual production cost data, which indicated 95% (R2 = 0.95) variance in the data between the predicted and actual production cost values. The model may help field engineers in computing their dimension stone operational cost during the cutting phase.

Nov 6, 2023

By M. H. Kirchner

Trackless mining at Thabazimbi Mine by M. H. KIRCHNER*. Pr. Eng.. B.Sc.. B.Sc. (Elec. Eng.}(Stellenbosch). Dip. Mining (Pta.) Certain aspects ?f the' methods used in the exploitation, by sub-level caving, of a wide, tabular, steeply dipping orebody are described, reference being made to the use of modern mechanized equipment. Statistics relating to production and labour, as well as some geological details, are given.

By M. H. Kirchner

Trackless mining at Thabazimbi Mine by M. H. KIRCHNER. Pr. Eng.. B.Sc.. B.Sc. (Elec. Eng.)(Stellenbosch). Dip. Mining (Pta.) Certain aspects of the' methods used in the exploitation, by sub-level caving, of a wide, tabular, steeply dipping orebody are described, reference being made to the use of modern mechanized equipment. Statistics relating to production and labour, as well as some geological details, are given.

By J. L. Havenga, L. J. van der Walt, J. T. Nel

"SynopsisThe development of plasma technology at Necsa started in the early 1980s, when the applicability of high-temperature plasmas in the nuclear fuel cycle was investigated. Since 1995, this plasma expertise has expanded to other industrial applications, for example mineral beneficiation, nanotechnology, fluorocarbon production and waste treatment, all of which are also of relevance to the nuclear industry.Necsa has demonstrated the manufacture of plasma-dissociated zircon, zirconium metal powder, carbon nanotubes, silicon carbide (SiC), zirconium carbide (ZrC) and boron carbide (B4C) at the laboratory and pilot plant scale. These materials are commonly used in the nuclear industry. Zirconium alloys are used as fuel cladding material for nuclear fuel assemblies.Necsa manufactured the monomer tetrafluoroethylene (TFE), using 150 and 450 kW DC plasma systems, from which the polymer polytetrafluoroethylene (PTFE) was synthesized for use in filters and as seals in nuclear plants. With the nuclear renaissance at hand, it was demonstrated that plasma technology can be used to produce hydrofluoric acid (HF), which is used in the manufacture of fluorine gas (F2) for the production of uranium hexafluoride (UF6) directly from the mineral calcium fluoride (CaF2) without the use of sulphuric acid as in the conventional process. The recovery of valuable uranium from nuclear waste such as filters, oils, and solids with plasma processes will also be discussed. The destruction of low-level nuclear waste by a plasma gasification system can reduce the volume of this waste by several orders in magnitude, resulting in huge savings in the storage costs. Another product of plasma technology is the encapsulation process for nuclear waste and the production of vitrified product, which could be used as filler material for medium-level nuclear waste.IntroductionDuring the 1980s, a plasma research and development programme was launched at the erstwhile Uranium Enrichment Corporation of South Africa (UCOR) at Valindaba outside Pretoria. The main purpose of this programme was to develop alternative and more economical processes for the processing and manufacturing of uranium compounds used in the nuclear fuel cycle. The conversion of UO2 (as received from uranium mines) to UF6, which is needed for enrichment, conventionally involves several laborious, expensive, chemical processing steps. Plasma processes can eliminate several of the intermediate steps. Enriched UF6 is converted to UO2, which is pressed into pellets that are used in nuclear power plants. Plasma technology could also be used in a modified and optimized conversion process."

Jan 1, 2015

By A. N. Brown

Professor D. G. Krige, of the Department of Mining Engineering of the University of the Witwatersrand, received the degree of Doctor of Engineering (honoris causa) from the University of Pretoria at the Autumn Graduation Ceremony in April 1981. He was honoured an outstanding engineer for his world-renowned pioneering work in the field of statistical methods of ore valuation, or geostatistics as it has become known. Metalliferous Ore Deposits A short course on the 'Evolution of Metalliferous Ore Deposits' will be held at Rhodes University, Grahamstown, from 8th to 13th February, 1982.

Jan 1, 1981

By M. D. Prendergast

Research into the ferrous metallurgy of Rhodesian Iron Age societies M. D. PRENDERGAST (Visitor) Iron-working was a widespread economic activity in Iron Age Rhodesia, and merits historical and metallurgical investigation. However, the research done so far has been incidental and poorly disseminated. This paper reviews the available evidence and the ways in which it can be interpreted by archaeologists and historical metallurgists. Particular attention is paid to smelting techniques and current metallurgical research, and brief suggestions are made for future research. v074n06p254.pdf

Jan 1, 1974

By T. J. Otto, C. H. Cloete, T. Mkhatshwa, T. J. van Heerden

The value realised by an open pit mine depends on the quality and integrity of the mine planning process as well as the level of execution against these mine plans. When managing the execution against the mine plan, how well the mine plan is executed spatially, is of critical importance. The short-term mine plan is the plan that is physically executed on most open pit mines. At the same time, the spatial mine-to-plan compliance is typically reconciled against the annual business plan. Short-term mine planning, therefore, plays an important role in the effectiveness of the spatial mine-to-plan compliance reconciliation process by providing operational teams with detailed designs and schedules, while ensuring that mining execution is spatially aligned with the business plan. The Sishen open pit iron ore mine (Sishen) strives to continuously improve spatial compliance to the business plan. Sishen enhanced the role that short-term mine planning plays in enabling the forward-looking component of the spatial mine-to-plan compliance reconciliation process. The enhanced short-term mine planning process focuses on detailed tactical sequence designs per mining pushback, the health of value chain buffers, spatial plan-to-plan reconciliation, and the associated management routines. This led to improved spatial mine-to-plan compliance to the business plan from 71% to 94% over the four-year period from 2020 to 2023 inclusive. These results indicate that the application of short-term mine planning as part of an integrated spatial mine-to-plan compliance process at open pit mines can contribute positively to improving the level of spatial execution against the business plan. This paper presents the enhancements made to the short-term mine planning process, which other open pit mining operations can consider to improve spatial mine-to-plan compliance.

May 27, 2025

By H. Moslemi

Metal sulphides are usually semiconductor and their electrical conductivity is low; therefore they are sources of electrons and promote electrochemical reactions. This phenomenon is of significant importance in sulphide flotation. The formation of a hydrophobic surface on the sulphide minerals is the result of various electrochemical reactions. Potential difference in the mineral-liquid interface plays an important role in the kinetics of the reactions, and consequently, on the flotation behaviour of sulphides. The value of the potential difference is influenced by different oxidation-reduction reactions at the interface area, and is measured by a two-electrode system in which an electrode is applied as reference electrode. In this study, we attempted to measure open-circuit potentials of pyrite, pyrrhotite, and steel electrodes with respect to the reference electrode. To verify the results, two reference electrodes, saturated calomel and gold, were used. Time-potential relations with respect to both reference electrodes show that the potential of both pyrite and pyrrhotite increases with time; however, this trend decreases for steel except when at pH 12. The results show a potential drop by an increase in pH value, except for steel, for which the opposite holds. This paper discusses galvanic interactions between minerals and grinding media in the grinding circuits, as well as among other minerals in the flotation processes.

Jan 1, 2012

The 86th Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House, Johannesburg, on Wednesday, 17th August, 1983. Professor A. N. Brown (President) was in the chair, and declared the meeting open at 16h05. This account of the proceedings includes only those matters that are not reported under the heading `Annual report and accounts' elsewhere in this issue.

Jan 1, 1983

A General Meeting, followed by a Colloquium on 'Pilot plants and problems of scale-up', was held on 22nd March, 1978, in the Main Hall, Kelvin House, Johannesburg. The President, Mr P. A. von Wielligh, opened the meeting at 09h15. He thanked the authors and contributors for their co-operation, and announced the names of the undermentioned candidates, who had been admitted to membership of the Institute:

Jan 1, 1978

By T. A. Silva, A. C. Bragança

Lime has been added to the iron ore slurry transported by the Samarco pipeline since its operation start-up in 1977.Initially, internal corrosion was the main concern therefore the reagent was used only for pH correction. Over the last ten years, though, transport of more complex slurries demanded a significantly higher dosage of lime to guarantee adequate rheology control. Several other reagents have been tested for the same purpose yet none has proven to be as effective regarding technical performance, environmental impact and cost. However, an alternative was sought so that the slurry rheology could still be controlled in case lime addition became impracticable. The objective of this paper is to present a technical solution for this matter, which takes into account environmental aspects. It consists of adding soda for pH correction and an organic coagulant as a rheology modifier. The latter is a quaternary ammonium salt which affected the slurry transport properties in the same manner as lime when tested in a laboratory. It showed no plug formation and allowed solid particles to settle, forming a loose sediment after rest. These results indicate a low probability of plug occurrence in the pipeline and the formation of a readily reslurryable sediment upon shutdown of the pumping system. Industrial tests should be performed in order to validate the laboratory results.

Jan 1, 2007

By U. C. Galimidi, J. M. Stewart, A. J. Van Rensburg

The effect of body movement on convective heat transfer from a man performing a block-stepping task was investigated experimentally by direct measurements of convective heat transfer. A series of experiments was conducted in which a nude man was required to stand at rest or to block step at 12 and 24 steps per minute. Wind speed, which was kept constant during each experiment, spanned the range 0,5 to 3,5 m/so Air temperature was kept constant at 43 °C in all the experiments. The results showed conclusively that the convective heat-transfer coefficient depends on the stepping rate. The effect of body motion can be regarded as being equivalent to an increase in the velocity of the free stream. The equivalent increase in air speed was found to be 0,36 and 0,77 m/s for 12 and 24 steps per minute respectively. Data from various sources, including the present study, indicate that wind speed should be increased by about 0,30,0,55, and 0,80 m/s to account for low, moderate, and vigorous body movements respectively. These findings are of direct relevance to the practical assessment of heat stress.

Jan 1, 1979

By A. Chiappone, M. Barla, U. Rabagliati, L. Repetto

ABSTRACT: The paper describes the application of both continuum and discontinuum modelling to the study of the stability conditions of the Alpetto mine, a high rock cut located in Cesana Brianza (Italy). The main objective is to provide valuable information for future mine planning and for the assessment of the stability conditions of the abandoned high rock cuts. Continuum modelling involved the applications of the finite difference method, whereas the distinct element method was used for discontinuum modelling. RESUME: L'article décrit l'application des méthodes de modélisation continue/discontinue pour l'étude des conditions de stabilité de la mine d' Alpetto, située à Cesana Brianza (Italie). Le but du travail consiste à determiner des paramètres utiles vis-à-vis du projet et d'estimer les conditions de stabilité de l'amas rocheux au terme de l'exploitation de la mine susmentionnée. La modélisation continue a impliqué l'application de la méthode des différences finis alors que la méthode des éléments distincts a été utilisée pour la modélisation discontinue. KURZFASSUNG: Der Artikel beschreibt die Verwendung der Modellierung von continuum und discontinuum zur Untersuchung/Studium der Stabilitätsbedingungen von der Alpetto Mine, hohe Aushubsfront in einer Felsmasse die sich in der Gemeinde von Cesana Brianza befindet. Das Hauptziel dieser Arbeit ist die Festlegung von Parametern die zur Planung nützlich/behilflich sein können sowie auch die Möglichkeit zur Analyse/Auswertung der Stabilität der Felsmasse-Front nach Aufhebung der Nutzung derselben. Die continuum Methode/Analyse wurde verwendet durch Unterstützung der Finite Differenz Methode da man für die Analyse der discontinuum (Fels als discontinuum beschrieben) der Distinct Elemente Methode verwendet hat.

Jan 1, 2003

By J. P. Coetzee

Dr. K. Gebhard In his excellent and comprehensive survey on the future development of the Iron and Steel Industry in South Africa, Mr. Coetzee has also mentioned the direct reduction processes as a possible method of converting iron ore to iron. Mr. Coetzee has made it quite clear that at this stage one should not consider these processes as a 'magic formula' which herald a 'break through'. I agree entirely with this point of view. Once upon a time I held the opposite view, but in the meantime I have revised my views. To do so, I had 40 years at my disposal. In 1930 I had the privilege of being connected with the first commercial sponge iron plant in Germany1 - a plant which was capable of producing 40 tons of sponge iron a day. We were determined to prove that the blast furnace would become obsolete in the near future. We considered it as an unnecessary detour to convert iron ore first into an iron-carbon alloy, which contained further quite a number of undesirable elements, and to remove this carbon by an endothermic process. Direct iron-making seemed to be a logical short cut. Unfortunately, we were not able to establish this 'short cut,', but the life of our sponge iron plant was cut short. We had solved all technical but not the economic problems. Basically the positon is still the same today - mainly economic and to a lesser degree technological aspects determine the rate at which sponge iron plants are installed. More has been said and written than done about direct reduction plants. I think that there are two main reasons for this stagnation in the introduction of direct reduction processes. The first reason is that modern blast furnaces are just too good and too economic ever to be replaced by direct reduction processes on a large scale. This, of course, already limits the field of application for direct reduction plants. The second reason is that sponge iron production and utilisation is based on technical considerations, which increase not only the production cost of sponge iron but also the conversion cost to steel to such an extent that under special conditions only are direct reduction plants an economic proposition. Are these technical considerations still as forceful and valid today as they were when 'direct steelmaking' was first contemplated? The development of sponge iron production as a method of direct

Jan 3, 1971

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. STANDARDS FOR ACCEPTANCE To merit consideration papers should be of sufficient high standard and contain matter that is new, interpretations that are novel or of new significance and conclusions that cast a fresh light on old ideas. Their publication should be of real interest to technical men and of benefit to mining and industry. Authors must realize that because a mine shaft is new or the mine itself is newly established, this in itself does not justify a paper unless significantly new techniques or processes were involved in the opening-up procedure. A few well selected diagrams and illustrations are often more pertinent than an amorphous mass of less well chosen material. Over-statement and dogmatism are jarring and have no place in technical writing. 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. Avoid the use of the first person, be objective and do not include irrelevant or extraneous matter. Papers should be submitted at least three months prior to the intended date of presentation. The text should be typewritten, double-spaced, on one side only of foolscap paper, leaving a left-hand margin of 11-inches, and should be submitted in duplicate to facilitate the work of the referees and editors. Galley proofs are sent to the 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. ORTHODOX SEQUENCE Title and author's name together with author's degrees, titles and position Summary, abstract or synopsis Introduction Development of the main substance Conclusions 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. Rulesfor Compositors and Readers. Humphrey Milford (familiarily known as the Oxford Rules). Fowler, H. W. & F. G. The King's English-Oxford University Press. Generally: 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 unamiguous. 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 parenthesis ( ), 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. Abbreviations and symbols are laid down in British Standard 1991 and proof correction symbols in British Standard 1219C. Abbreviations are the same for the singular and plural, e.g. ft for foot and feet, lb for pound and pounds. Percentages are written in the text as per cent; the symbol % is restricted to tables. Likewise ft and in. should be used, x' y" only being permissible in diagrams and plans. Drawings and diagrams are to be in black India ink and should be about 6 in. wide. Numbering of tables should be in Roman numerals: I, II, etc. and figures in Arabic numerals: Fig. 1, Fig. 2, etc. Photographs should be black and white glossy prints. As a guide to the printer the author should indicate by means of notes in the margin of the typescript where drawings and diagrams, etc. are to appear in the text. 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. SUMMARY ABSTRACT OR SYNOPSIS It is most important that the summary 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. FOOTNOTESAND REFERENCES Footnotes should be resorted to 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.

By J. Palarski

Long waling is used in most Polish coal seams, with backfilling to support the roof, to create an artificial hanging wall to prevent movement if the rockmass, and to eliminate the fire hazard in abandoned mine workings. This paper discusses the results if tests conducted on 7 different backfill mixtures, and gives equations for the estimation if the flow if backfill slurries through gravitational pipelines.

Jan 1, 1994

By Arvi Parbo

I would like to use the occasion to reflect on how the world environment for the minerals industry is undergoing substantial change, and how this change may affect the industry. I have given my talk the title 'The Quest For Competitive Edge', because the net effect of the changes taking place is that competition is increasing. To set the scene, let us look back at the situation which has existed in our industry in the past.

Jan 1, 1993

"Chairman: Professor C. O. Frush Rapporteur: Mr A. C. SchmidtPapers:Planning of underground copper mining by J. K. Williams, L. Smith and M. P. WellsLinear programming models of copper leach and solvent extraction plants by W. P. C. Duyvesteyn, J. R. Cutland and J. R. L. RusselPlanning and forecasting stope production by D. W. Kappes and P. F. X. Moussett-JonesA proposed method of dynamic ore reserve assessment for a caving system of mining by A. F. Spinks and S. P. NicholsThe initial point made by Mr L. Smith in presenting his paper was that the planning aid outlined in the preprint was neither sophisticated nor complicated. However, it was a system which worked and was a very real way in which the computer was being used to assist miners, in particular, who at the present moment have very little experience in the use of computers.Mr Smith apologised for the fact that the editors of the paper had eliminated all reference to 'time'. This was very unfortunate because the essence of the system was that it saved time, which was one of the main points made in the paper.The operations being planned by this means cover the Rokana orebody which is a stratiform body mined by open stoping.The planner has to decide how much ore to mine from each base in each time period of his plan, that is, from three to four months hence to a year ahead. Normal procedure is for the planner to have discussions with the underground manager on some of the information he requires. The sort of information needed is (i) tramming limits for each face, (ii) extraction and grade factors, (iii) the present status of mining operations so that the planner knows where to start the new plan, and, (iv) details of any other mining consider¬ations that need to be incorporated in the plan.The objective at this point is to produce an initial plan for discussion purposes. All the information required comes from one sheet per stops and shows, inter alia, the stope identifier, the length along strike, the ore tonnage, the copper and cobalt grades and, finally, the extraction and grade factors.The program itself, among many other things, checks the data for validity, compatibility, completeness and credibility and prints error messages accordingly. Output from this system is in the form of a summary of production from each face, as well as giving the figures of ore reserve depletion. This summary indicates which slopes are to be mined in this time period, the original survey grades (copper and cobalt), the estimated production grades, how much is to be mined from each stope and the copper and cobalt production accordingly."

Jan 1, 2014