Search Documents

By Y. Fan, D. H. Zhang, J. Y. Xu

The hydrogeological conditions in the Chambishi mine area in Zambia. were investigated. Chambishi is a very wet mine and groundwater discharge costs are high. The research goal was to identify methods to reduce the discharge costs without greatly affecting the mining process. Hydrogeological data was obtained from measurements in drill-holes and from drill cores. The differences in structural deformation in different areas determine whether a layer of rock is an aquifer. In the mine region, the Lower Roan Group ore shale and quartz-sandstone unconformably lie on the basal schist and granite aquifuge. The Upper Roan Group dolomite is continuously distributed over a large area around the orebody. This dolomite is the main target of groundwater control efforts, and its water yield is also influenced by the deformation intensity. Based on the observations, backfilling was gradually adopted to appropriately safeguard the integrity of the aquifuge above the orebody. The overlapping relationship between the aquifer and aquifuge has been utilized to increase mine drainage efficiency. This measure has not only greatly reduced the costs of mine drainage, but also improced protection of the groundwater environment. The old drill-holes that were not sealed after exploration drilling were grouted. Further, possible water-conducting fracture zones were investigated. Cover drilling towards the suspected zone was conducted to prevent the high-pressure groundwater from shallower aquifers from entering stopes in deep areas of the mine.

Jun 10, 2024

"Chairman: Professor J. de V. Lambrechts Rapporteur: Mr R. HempPapers:Computer-aided design of a flash smelting installation by M. A. T. Cocquerel, R. T. Gates and L. A. GreenPlanning of mine ventilation by E. U. Reuther and A. DohrnenCoal mine ventilation systems in the U.S.A. by R. Stefanko and R. V. Ramani Heat flow models in ventilation planning by A. J. Dickson and A. M. StarfieldThe first of the papers in the session dealt with a flash smelter installation, while the remaining three papers dealt with mine ventilation. In view of this the Chairman proposed that the paper on flash smelting be introduced and discussed first, after which the remaining three papers would be introduced followed by discussion on all three.Dr Cocquerel, who presented the first paper, used some typical flow diagrams to illustrate the process and stated that the program considered only steady-state operations and did not take into account the dynamical changes. Subjective judgment was necessary for the preparation of input data and some degree of user appreciation was required.Dr Cocquerel said that no work bad yet been done on an optimization program, but that this was being considered. Such a program would require a large amount of physical and chemical data which were not yet available. The variables to be optimized were the energy and material consumptions and the loss of metal in the slag.The Chairman opened the discussion by asking Dr Cocquerel if he could give a brief description of the flash smelting process for the benefit of those not familiar with the subject. Dr Coquerel replied that in the Outokumpu process con¬centrates were injected directly into the furnace, and that the process was somewhat analogous to flash distillation or evaporation processes, but was perhaps closer to the burning of pulverized fuel.The process had two distinct advantages. First, the heat evolved in the smelting reaction was used to heat the furnace, which resulted in less fuel consumption, and, second, the effluent gases were cheaper to treat than the effluent gases from other pyrometallurgical processes. This was important particularly in view of the current interest in pollution problems.Mr P. Marais thought that the authors had done themselves an injustice by not including details of the very complex processes taking place in the furnace."

Jan 1, 2014

By D. Krebs, Tero Korhonen, X. Yang, A. Kirpala, N. Heino

At present, over 85% of the world’s rare earth oxides are produced from the bastnäsite ores, found mainly in China. Meanwhile, the ion adsorption ores are the most important sources for heavy rare earth production. As the demand for rare earth materials in the world increases, other forms of rare earth deposits will become new potential resources of rare earth production in the future. In this paper, flotation performance of a steenstrupine ore from the Kvanefjeld deposit for rare earth recovery was studied through laboratory bench testwork. The effects of various factors including grinding size and collector dosage on recovery and selectivity of the selected rare earth elements, La, Ce and Y, were investigated. A rare earth concentrate with the grades of La 2.8 wt%, Ce 5.1 wt% and Y 1.0 wt% at recoveries of 80.5% La, 79.8% Ce and 55.3% Y was obtained in optimum conditions. Further potential to improve the efficiency of REE flotation was discussed. Keywords: Rare earth elements, flotation, steenstrupine, Kvanefjeld deposit

Jan 1, 2020

Council and Standing Committees, 1978-1979 President: Dr M. G. Atmore. Vice-Presidents: D. A. Viljoen and Dr P. R. Jochens. Honorary Treasurer: J. K. E. Douglas. Immediate Past President: P. A. von Wielligh. Members of Council: J. D. Austin, A. N. Brown, H. E. James, Prof. R. P. King, Dr D. G. Krige, Prof. F. Q. P. Leiding, D. G. Malan, C. S. McPhail, J. C. Mostert, G. Y. Nisbet, H. G. M. Rose, W. T. Ruhmer, G. C. Thompson, R. A. von Maltitz. Chairman, Witbank-Middelburg Branch: T. S. Wilmot. Chairman, Orange Free State-Klerksdorp Branch: H. M. W. Eschenburg. Past Presidents Serving on Council: R. J. Adamson, H. Britten, J. K. E. Douglas, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plewman, Dr R. E. Robinson, Dr M. D. G. Salamon, P. W. J. van Rensburg. Standing Committee Chairmen: Membership, Dr P. R. Jochens ; Technical Programme - Metallurgy, Prof. R. P. King ; Technical Programme - Mining, H. G. M. Rose; Vacation School - Metallurgy, J. C. Mostert; Vacation School - Mining, D. G. Malan/J. D. Austin; Awards, P. A. von Wielligh; Excursions, D. A. Viljoen; Adjudication, P. A. von Wielligh; Constitution, Rules and Policy, P. A. von Wielligh; Monograph Series, Dr R. E. Robinson; Professional and Technician Train¬ing Committee, Dr M. D. G. Salamon; Career Guidance, D. G. Malan; Phoenix National Committee, Dr R. E. Robinson; 1982 World Congress, Dr M. G. Atmore; Witbank Coal Colloquium, Dr P. R. Jochens; Mines and Works, P. A. von Wielligh.

Jan 1, 1979

Council and Standing Committees-1984/85 President: J.D. Austin Vice Presidents: H.E. James and Dr H. Wagner Immediate Past President: Prof. R.P. King Honorary Treasurer: Prof. D.G. Krige Members of Council: B.C. Alberts, Prof. S. Budavari, E.B. Crocker, N.J. Devine, C.E. Fivaz, J.S. Freer, Prof. G.G. Garrett, J.J. Geldenhuys, Dr A.K. Haines, R.W.O. Kersten, Dr B.K. Loveday, I.D. Matthews, G. Maude, H.G. Mosenthal, B.E. Protheroe, Dr O.K.H. Steffen, Dr P.T. Wedepohl Chairman, Witbank/Middelburg Branch: W.C. Mather Chairman, Orange Free State/Klerksdorp Branch: Dr M.A. Orridge Past Presidents Serving on Council: Dr M.G. Atmore, Prof. A.N. Brown, Dr P.R. Jochens, G.Y. Nisbet, Prof. R.P. Plewman, Dr R.E. Robinson, Prof. M.D.G. Salamon, P.W.J. van Rensburg, D.A. Viljoen, P.A. von Wielligh Standing Committee Chairmen: Adjudication, Prof. R.P. King; Awards, Prof. R.P. King; Constitution, Rules and Policy, Prof. R.P. King; Excursions and Banquet, B.E. Protheroe; Journal, H.E. James; Membership, Dr H. Wagner; Phoenix National Committee, Dr M.G. Atmore; SAIMM School-Extractive Metallurgy, J.S. Freer; SAIMM School-Mining, Prof. S. Budavari; Special Publications, J.D. Austin; Technical Programme¬Extractive Metallurgy, Dr B.K. Loveday; Technical Programme-Mining, J.J. Geldenhuys; Technical Programme-Physical Metallurgy, Dr P.T. Wedepohl; Training, Career Guidance and Education, Prof. R.P. King; World Mining Congress-National Committee, Prof. R.P. Plewman; Working Group Physical Metallurgy, Prof. G. G. Garrett

Jan 1, 1985

By E. P. Gush

Diamonds, an enigma in a mineral resource sense. Chemically, diamonds are no more than carbon crystals in a cubic system-formed one might add under conditions of great pressure and temperature. They have certain physical properties which are fairly unique. They are very hard, they have a high refractive index, they luminesce, some of them fluoresce, they have a high specific gravity, they don't wet and they are a good conductor of heat. In a way, a rather clinical set of qualities. Of course, these qualities are what give diamonds their use and their beauty. It is on the emotional side that they get complex and stir memories of legends, of beauty, of wealth and romance, of war, happiness, bad luck and curses. It is on the emotional side that the value of a diamond is established, if such a thing is possible. Diamonds are extremely varied, there are more than 5000 categories into which they are sorted, so there is room at each point across the spectrum for their individualities to emerge, and accordingly their attractiveness to each buyer is unique.

Jan 1, 1994

Council for 1998/99 President R.P. Mohring President Elect J.R. Dixon Vice Presidents Senior M.H. Rogers Junior Dr L.A. Cramer Immediate Past President Dr N.A. Barcza Honorary Treasure J.A. Cruise Members of Council J.P.W. Bennie E.G. de Villiers A.A.B. Douglas F.M.G. Egerton R. Graham Dr R.G. Gürtunca Dr R.V.R. Handfield-Jones P.J. Knottenbelt R.G.B. Pickering* P.S. Piper Prof. R.F. Sandenbergh Dr T.R. Stacey D.J. van Niekerk P.J. Venter J.C. Viljoen

Jan 1, 1998

By P. Minkkinen, R. C. A. Minnitt

Particle size distribution analysis is important to many industries for assessing product quality, process efficiency, and compliance with contractual standards, while ensuring sample accuracy, and representativeness. Inaccurate particle size distribution results, arising from fines due to excessive handling can lead to penalties and buyer-seller disputes. A non-representative particle size distribution means samples will not accurately represent the chemical components either. Sampling blasthole cuttings poses challenges due to large material volumes, segregation, and uneven settling of particles in dense gold bearing ores. Commonly used sampling methods, such as spear or sectoral sampling, may lack representativeness. Particle size distribution analysis is crucial for evaluating sampling methods by comparing test sample representativeness against a reference standard derived from multiple particle size distribution analyses. Acceptable samples must fall within the 97.5% confidence intervals of the standard; deviations analyses lying outside these boundaries indicate a strong likelihood of segregation errors. A case study demonstrates this approach by using a 6.005 kg benchmark sample to assess two additional samples (1 kg and 5 kg), highlighting particle size distribution’s role in detecting sampling errors and refining protocols. An example of three test samples collected from reverse circulation drill cuttings compared to a standard reference sample is presented to illustrate a quality assurance/quality control procedure for reverse circulation drilling.

Oct 2, 2025

By O. K. H. Sheff

An editorial in the April 1990 edition of Mining Magazine is worth a wider audience in South Africa, particularly as the SAIMM enters its own centenary decade and the process of change in the minerals industry world-wide makes increasing demands on the professionalism of its leaders. The editorial considers the changing status of engineers, who up to the 1880s had been held in high regard by society. Alumina and bauxite Economists forecast a slower economic growth rate in 1990, but expect continued increase in demand for aluminum at a 3 per cent annual rate during the decade. Structural and numerical analysis Struceng & Femcad (structural analysis and finiteelement method) is a conference and exhibition that is to be held in Grenoble (France) on 17th and 18th October, 1990. It is sponsored by the Institute for Industrial Technology Transfer (ITT-International).

Jan 1, 1990

"Chairman: Professor J. C. Griffiths Rapporteur: Mr J. P. G. PRETORIUSPapers:Mine-mill production scheduling by dynamic programming by R. J. Roman Optimization of a large mining venture by J. C. Paynter, B. K. Loveday and C. G. Robinson Economic surface mining of multiple seams by T. V. Falkie and W. E. PorterIn introducing his paper, Mr Roman said that whereas in manufacturing plants the yearly production levels were usually chosen to produce the largest annual cash flow, in a mining operation, the raw materials (ore) were exhaustible so that the production had to be scheduled to maximize the total net present worth of the operation. This optimum production schedule could be determined by using dynamic programming. The required information was readily available to management at most mines. The 'possible operating range' of production rates lay between the rate with the highest profit per ton. and that with the highest profit per year. The optimum production rate started typically at the top of this range and decreased slowly as the deposit was depleted.Dynamic programming was used to determine several production schedules for a hypothetical mine-mill complex. The effects of changes in the ore grade estimates, size of deposit and acceptable rate of interest on the production schedule were taken into account. Apart from the fact that the net present worth of the overall profits was larger than that obtained by conventional methods, it appeared from the cases studied that the amount of metal recovered was also greater.Dr it P. King commented that this was a very interesting application of dynamic programming. He pointed out, however, that the market price of the metal was likely to vary significantly and randomly during the life of the mine, and he suggested that the problem should, therefore, be reformulated as a stochastic dynamic programming problem.If the price of the metal rose to abnormally high levels, a much higher than normal production rate could be expected. The results of analyses given in Table 5 showed that the production rate was a function of market price. In his view the stochastic problem could be solved just as easily as the deterministic problem.In reply to a question by Dr King as to whether the function relating recovery to production rate (Table I) was based on real data, the author replied that it was based on the results of an analysis conducted at the Union Carbide Corporation's Pine Creek tungsten mine in California.Dr D. M. Hawkins stated that costs were incurred when the production rate was altered, for example, in appointing or laying off staff, and that in practice it may be necessary to take these costs into account in finding the optimum production rate. Mr Roman replied that, while normal administrative costs were accounted for, the additional costs incurred in appointing and laying off staff were not taken into account."

Jan 1, 2014

By J. Grobler, J. Zietsman

"Understanding the influence of feed material mineral assemblage on spiral separation is paramount for the successful and consistent operation of a spiral plant. Plant stability is required to maintain high recovery of valuable heavy minerals (VHM). Standard material analysis methods used in the heavy mineral industry to evaluate spiral separation behaviour are unable to quantify performance differences in the case of large variations in feed assemblage. This study illustrates a systematic approach to evaluate spiral separation performance. This technique was applied on a four-stage spiral plant. The performance information was used in a circuit simulation to clearly illustrate the importance of correct setting of the spiral splitter position and resulting spiral mass loading to ensure optimal circuit stability and maximum VHM recovery.IntroductionHeavy mineral sands deposits generally consist of naturally fine-grained, free-flowing sand due to the way in which the deposit was formed. The size of the heavy minerals market is roughly 8 Mt/a of zircon and titanium combined (Iluka, 2013). If an average combined feed grade of 5% zircon and titanium and an average combined overall product recovery of 80% are assumed, the resulting run-of-mine feed tons that would require primary spiral beneficiation is 200 Mt/a. The number of spirals required for the processing of this material, assuming 6500 operating hours per annum, an average of 2 t/h per start, and the same number of rougher spirals as other duty spirals, is over 30 000 spirals for the heavy mineral sands business alone. These numbers clearly illustrate the importance of the spiral in the heavy mineral industry.The aim of a spiral plant in the primary processing value chain of a heavy mineral process is to reject non-valuable quartz (a light mineral) from various valuable heavy minerals (VHM). The product from the spiral plant is a heavy mineral concentrate that has a reasonable grade (more than 90% heavy minerals) at a reasonable heavy mineral recovery (greater than 90%). This benchmark is fairly easy to achieve if all the mineral particles are well liberated (as in the case free-flowing sand), the feed is properly deslimed (-45 µm fraction removed to less than 5% of the solids mass), and the spirals are fed within design solids concentration (water to solids ratio) and design spiral load (dry tons per hour per start)."

Jan 1, 2017

By M. R. Khalesi, S. Arfania

"Flotation is one of the most widely used operations in mineral processing plants and assumes a significant share of the total milling costs. The purpose of this paper is to introduce a new set of capital and operating cost models for major flotation machines based on the application of single (SRA) and multiple regression analysis (MRA). Thirty-seven major flotation machines were analysed for this purpose. Depending on the machinery type, different technical variables such as diameter, required air flow rate, required floor space, cell volume, required air pressure, and power were considered as predictor variables, individually (in SRA) or simultaneously (in MRA). Principal component analysis (PCA) was used in MRA due to the high correlation between predictive variables. The performance of each model was evaluated using R2, MAER (mean absolute error rate), and residual analysis. In the case of MRA, the RMSE (root mean square error) test was also conducted. Maximum obtained MAER of 13.5% and minimum R2 of 0.86 indicated that these models could be applied as credible tools in estimation of capital and operating costs of flotation machines for design and feasibility studies.IntroductionMineral processing is a vital part of mining projects and mainly involves comminution, sizing, concentration, extractive metallurgical processes, and dewatering. Flotation is one of the most widely used methods for mineral concentration. Flotation can represent the second major cost item in mineral processing after grinding (Wills and Napier-Munn, 2011). Accordingly, it is a main concern of mining project managers to select and optimize flotation circuits in order to decrease costs and increase productivity. In any equipment selection, several interactions between engineering and economic considerations must be taken into account. Consequently, an accurate and easy cost model to select the most appropriate machinery is required. Moreover, cost models could be used in flow sheet simulations applied in design and optimization. Models of unit operations built into the simulators could be improved by linking the equipment cost models (Khalesi et al., 2015)."

Jan 1, 2017

By L. A. Vermeulen, C. P. Campbell, D. D. Howat

The production 01material liner than 75 µm in a number of open-circuit mills was investigated. The mils ranged from laboratory rod and ball mils treating a variety 01 ores to large industrial rod mils treating gold and copper ores. It was shown that the dependence on feed rate 01 the production 01 material liner than 751J.1T1 can be accurately described by a simple formula that was derived in previous work. In some 01 the systems reviewed, it proved possible to assess the feed rate 01 ore to the mil at which the rate 01 production 01 material finer than 75 µm can be maximized.

Jan 1, 1991

By M. L. Pududu, B. Ceki, K. Mohajane

This study was aimed at determining the effects of industrial action on profitability in the South African platinum mining sector. We compared companies where employees engaged in industrial action (affected companies) to strike-free companies (competing companies). Industrial action refers to strikes by rockdrillers, as these strikes typically result in the shutdown of production at the mines affected. A t-statistics analysis of significant differences in revenue and earnings of affected and non-affected platinum companies was conducted using data from platinum mining companies listed on the Johannesburg Stock Exchange from 2011 to 2015. Contrary to international studies, which suggest that the spillover effects of industrial action positively affect competing companies, our findings show that profits in the platinum sector decrease significantly during strike periods for both affected and competing companies. The results indicate industrial action is a threat to the profitability of all companies, and that employee demands should be prioritized and negotiated before they result in industrial action. Improved dialogue between management, labour unions, and employees in the platinum mining industry is recommended. The study contributes to the scanty literature on the effect of industrial action on the profitability of mining companies in a developing economy.

Dec 13, 2022

The term geostatistics was introduced by Matheron (1960) to cover the development and application of mathematical and statistical models which take specific account of the spatial structure of a 'regionalised' variable. In ore valuation the relative positions of available ore values within an ore body or portion thereof, can only be ignored in the unlikely case where there is no significant pattern of association or correlation between them - that is, if they do not disclose any significant spatial structure. A structure might not be evident in the available data, e.g. where the spacing of the available values is relatively wide such as in surface drilling on a new deep gold mine. However, practical selective mining considerations could dictate the need for eventual underground valuation on a scale much smaller than that represented by this spacing and the possibility of a significant structure on such a smaller scale cannot then be ignored. Some spatial structure must be present wherever the average variability among the values of check ore samples from the same, adjacent or nearby grooves or of borehole cores from the deflections in the same borehole, is lower than the overall variability for ore values within the whole ore body. Another practical check on the presence of a spatial structure is where it is evident that there is or will be a significant variation in the ore grades for individual ore blocks. Any correlation between peripheral and follow-up internal ore block values also provides evidence of a spatial structure, and hence the regression techniques covered in §1.16-1.2 1 can be accepted as the first application of the geostatistical procedures. The spatial structure of a regionalised variable can be studied and measured by the pattern, usually a decreasing function, in the level of correlation or of the covariance between pairs of values as the distance or lag between the values increases, that is, by the correlogram or covariogram (Krige, 1968, 1969, 1976; and Fig. 18). In geostatistics, for various practical and theoretical reasons (Matheron, 1960, 1971), the measure most commonly used is the semivario- gram, which increases as the lag increases. The semivariogram and covariance values are interrelated and for the lognormal- de Wijsian pattern used extensively for gold ore valuation both measures as well as their relationship can be defined on a fairly straightforward basis. Provided the underlying as- sumptions are realistic, the choice of measure - correlogram, covariogram or semivariogram - will be dictated mainly by convenience. Paragraph 2.2 will cover some general geostatistical terms and $2.3-2.12 will deal mainly with the theoretical side of the lognormal-de Wijsian model for spatial structures. Wherever the relevant variable lends itself to normalisation via the 3-parameter lognormal distribution (see 51.9) the de Wijsian semivariogram model is also likely to be suitable and will provide substantial advantages in application. Various practical applications will be covered in Section 3. Although confined to the lognormal-de Wijsian model, much of the theory covered and the general approach is applicable to all spatial structures. [ ]

Jan 1, 1981

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 11/2 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. Rules for 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: 1, 11, 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. FOOTNOTES AND 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 P. E. Venteer

The Grootegeluk coal-processing plant treats 3 kt of raw coal per hour to produce a middlings fuel coal and a coking coal fraction with ash contents of 35 and 10 per cent respectively. The plus 0,5 mm fraction is treated by heavy-medium processes, the final top size of the coal being 15 mm. About 400 t of minus 0,5 mm coal per hour is subjected to froth flotation. The routes originally considered for the processing of this fine coal were froth flotation, shaking tables, heavy-medium cyclones, and water only cyclones in combination with froth flotation. The results from tests on the fines arising from a small-trial open-cast mine are discussed. When the froth flotation route was decided upon, further tests were conducted on the selection of the equipment most suited to the particular requirements of this coal and the rest of the plant. Tests using different types of flotation cells and dewatering equipment are discussed. During the commissioning, several operational problems were encountered, and the work done to find the best solutions is discussed.

Jan 1, 1984

By X. Zhang, E. Li, Y. Xiao, Z. Yu, H. Han, J. Xie, J. Tian, W. Sun, K. Hong

In a pulp environment, the surface properties of magnesite and dolomite tend to be similar, due to the re-adsorption of dissolved calcium species, which makes the flotation separation difficult. In this paper, the chelating reagent EDTA is introduced to eliminate the adverse influence of the calcium species and to restore the selectivity of magnesite-dolomite separation using sodium hexametaphosphate (SHMP) as a depressant. Flotation experiments confirm that the recovery of magnesite improves significantly in the presence of EDTA. Zeta potential experiments confirm that the negatively charged EDTA4+ and HEDTA3+ species can form soluble and stable chelates with positively charged Ca2+ and Ca(OH)+ species preventing their adsorption on the magnesite surface. Adsorption measurements prove the addition of EDTA can decrease the adsorption of depressant SHMP on the magnesite surface. X-ray photoelectron spectroscopy (XPS) measurements further confirm the transformation from the surface of magnesite to dolomite in the presence of calcium ions, and the possible adsorption mechanism of EDTA and SHMP on the magnesite and dolomite surface. Key words: Magnesite; Dolomite; Surface dissolution; Flotation separation

Jan 1, 2020

By J. Jacob

Diamondiferous linear beaches in Mining Area No. 1 have been the mainstay of Namdeb?s diamond production for more than 80 years. Most of the onshore beaches have been mined out, but in recent years mining has been extended offshore into the surf zone through a process of beach accretion. A total of 61.6 million carats has been produced from the gravel beaches since their discovery in 1928, and Mining Area No. 1 is considered to have great remaining potential from areas currently submerged under water. To date, the surf zone has remained largely unexplored due to the consistently strong winds, currents, and large waves which make access to this area extremely difficult. This paper describes the processes used in developing a practical methodology for exploration of the surf zone in a domain extending approximately 22 km long in a northwest?southeast direction and 0.3 km wide in a perpendicular direction adjacent to the current Mining Area No 1. The vigorous surf zone poses multiple technical challenges in terms of obtaining geological and diamond information. In order to access the area for sampling, a jack-up walking probe drill platform (PDP) with a 5-inch diameter reverse-circulation drill has been developed to carry out exploration drilling in the dynamic surf zone. The hydraulically driven platform has eight legs, each of which is 18 m long. Four of the legs are in fixed positions on the fore and aft sides of the platform. The other four moveable legs are fitted to sliding frames attached to the port and starboard sides of the platform. The sets of fixed and moveable legs can be raised and lowered by hydraulically powered jacking stations. By alternately lifting and lowering the sets of fixed and moveable legs in conjunction with the frames moving back and forth horizontally, a walking action is performed by the PDP. The platform can walk at a speed of 10?15 m/h, depending on weather and footwall conditions. Optimization of sampling for diamondiferous gravel occurrence in Mining Area No.1 was undertaken through creation of a virtual orebody on which different sample configurations were tested. The input data for the construction of a virtual orebody comprises a set of drilling data, collected from recently accreted areas directly adjacent to the 22 km × 0.3 km target domain. The input drilling data covers only 34% of the domain, and for the purpose of this study, a single realization is deemed to be sufficient. The texture obtained from using only the drilling data to construct a simulation did not make geological sense; hence it was necessary to make use of analog data in order to improve the simulation. The first analog data used consists of the gully patterns found in the metasedimentary Precambrian bedrock footwall. Gullies are, in general, gravel filled and it is fair to assume that gully patterns form a subset of the total gravel occurrence. Total gravel occurrence includes marine terraces (governed by sealevel stands) above bedrock peaks, together with gravel within gullies below bedrock peaks. The second analog ?data? introduced is through the use of ?expert interpretation?. The indicator drilling data is interpreted by expert opinion and the 2-dimensional result is hand-sketched, digitized, and then pixelated. The pixelated data set is then used as input for variogram calculation. This study cannot provide a single definite optimization result as the nature of the data does not permit this. The use of different validation approaches (conditioning data, where available; expert interpretation; and gully pattern data), however, can give a very good indication of how to balance sampling effort with de-risking aspects related to geological continuity. Work undertaken by sampling the simulation will give an assessment of the relative probabilities of determining gravel occurrence in the study area. This study showed that a 50 m × 400 m cross-configuration will be a good initial sample spacing for highlighting areas where gravel may be absent, and further infill drilling may be required. The relative efficiency of a 50 m × 400 m cross off-set sampling configuration has been demonstrated using a trumpet curve versus sampling effort when using kriging as the estimation method. Keywords sampling configuration, marine diamonds, orebody simulation.

Jan 1, 2014

By G. L. C. Young

The first full-scale Reichert cone concentrating plant to be erected at a large South African gold mine was at President Steyn Gold Mining Company, Welkom. ThiR plant was installed as a part of the runof-mine mill extension of 150000 t per month that was commissioned in 1976-1977.

Jan 1, 1982