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By L. S. Belyayeva, A. S. Chumak, N. N. Boyko, A. V. Bondarenko

Analysis of results of many years concerned study of the fire hazard parameters of the material of the mine conveyor belts come in for use at the mines of the Ukraine in 1984-2002 that was carried out in the laboratories of the Scientific-Research Institute of Mine-Rescue Work is adduced in the paper. The basic tendencies on raising the fire safety of the conveyor belts that are retraced in their world production are shown.

Jan 1, 2003

By J. Levin, I. J. Corrans

Wet high-intensity magnetic separation (WHIMS) for the concentration of gold and uranium was tested on many Witwatersrand cyanidation residues, and on some ores and flotation tailings. The results varied, but many indicated recoveries of over 60 per cent of the gold and uranium. The main source of loss is the inefficiency of WHIMS for material of smaller particle size than 20fLm. The recoveries in the continuous tests were lower than those in the batch tests. The continuous tests indicated an operational difficulty that could be experienced in practice, namely the tendency for wood chips and ferromagnetic particles to block the matrix of the separator. It was decided that a solution to the problem lies in the modification of the separator to allow continuous removal of the matrix for cleaning. A system has been developed for this purpose and is being demonstrated on a pilot-plant scale. Promising results were obtained in tests on a process that combines a coarse grind, gravity concentration, and WHIMS. In the gravity-concentration step, considerable recoveries, generally over SO per cent, of high-grade pyrite. were obtained, together with high recoveries of gold and moderate, but possibly important, recoveries of uranium. A simple model describing the operation of the WHIMS machine in terms of the operating parameters is described. This should reduce the amount of empirical test work required for the optimization of operating conditions and should provide a basis for scale-up calculations. The economics of the WHIMS process is discussed.

Jan 1, 1979

By Marthie Kotze, Jacolien Wyethe, Bert Van Hege, Richard Bell

Base metal refinery effluent streams may contain low metal concentrations that cannot be recovered by precipitation. Although the concentration is low, the total mass of unrecovered metal can have significant value because of the volumes of effluent generated. This metal may be recovered with high efficiency using selective ion exchange resins. Three process schemes are considered, viz., fixed bed column ion exchange, continuous countercurrent resin-in pulp, and continuous carousel resin-in-pulp. Each of these has different requirements in terms of equipment, resin inventory, capital and operating costs, and different limitations on feed conditions. Bateman and Mintek recently developed a model which allows an upfront economical evaluation of ion exchange options. The model evaluates the capital and operating costs for each process scheme for various base metals. This provides a general guideline for selecting the appropriate process arrangement for a given process stream.

Jan 1, 2005

By D. D. Marsden, L. E. Kun

Although a regulation is in force that all water used underground shall be free of bacterial contamination, in practice it is often very difficult to accomplish this. The standard method of disinfection m South African mines IS treatment with calcium hypochlorite, although liquid sodium hypochlorite is used at a few sites. Primarily because the process depends on human control for the addition of the hypochlorite and the regulation of its now, it is frequently found difficult to disinfect mine water adequately and continuously. In many marine environments, chlorine generated by the electrolysis of seawater in its passage through an electric cell is used for disinfection. The generation procedure is continuous and needs no human control except for occasional checking of the equipment. This paper describes the successful implementation of the process, suitably .modified, .at four underground sites. After severe scaling problems had been overcome, a procedure resulted that chlorinates considerably more effectively than the previous system (dosing with calcium hypochlorite), and that has a lower amortized operating cost.

Jan 1, 1981

By A E. Paterson

General aluminium corrosion charts based on 1100 alloy listing product and temperature have been developed by AFSA, mainly from available sources. The categories of corrosion expectation are fairly wide. As a result the charts are more useful in indicating what is not suited as distinct from what is. The question of how to develop useful information is assessed. Having discarded improbable options one is left with the need to refine the possible. Within each alloy group corrosion potential differs. From an engineering application point of view, the corrosion resisting marine alloys, the 5xxx series show increasing corrosion as the percentage of Magnesium increases. An important issue is that as the welding filler used for 5xxx series is Mg rich (to avoid hot cracking), the filler is likely to show the weakest resistance. In addition, when subjected to fatigue loading, the preference for critical joints is to dress the joint to the level of the base material. Overheating of the weld extends the HAZ zone and weakens the material as Mg moves to the grain boundaries. Indicator chart refinement approaches suited to aluminium use in commercial transport are discussed.

Jan 1, 2006

By H. M. Dus, D. J. Smith

Resistivity tests indicated that, at temperatures lower than 1450°C, reducing agents alone, as well as burdens consisting of high-carbon ferrochromium and reducing agents, exhibit wide differences in resistivity. These differences are less pronounced at elevated temperatures. The resistivity of a reducing agent and the volume fraction it occupies are important factors controlling the resistivity of burdens of high-carbon ferrochromium. A mathematical model is formulated to describe the dependence of the resistivity of mixtures of conducting and insulating particles on the particle sizes and the volume fraction occupied by the conducting phase. The resistivity of burdens of high-carbon ferrochromium is high if the particle size of the reducing agent is larger than that of the other components of the burden. A number of reducing agents showed small variations in their reactivity towards chromite ore in the solid state. However, with chromite ore in the liquid state, reduction proceeded more rapidly with reducing agents occupying larger volume fractions. During the smelting of manganese ore, high initial rates of reduction were observed for reducing agents that had a high reactivity towards carbon dioxide and a high content of volatile matter, and that occupied a large volume fraction. High liq'uid-state reactivities were observed for reducing agents occupying a large volume fraction and having a Iow degree of graphitization.

Jan 1, 1980

By A. W. Bryson, J. D. le Roux, B. D. Young

Several rate models for the adsorption of gold cyanide from aqueous solution onto activated carbon are given in the literature. The purpose of this study is to critically examine their ability to simulate the adsorption process over a wide range of conditions. An account is given of a comprehensive set of experimental work on the kinetics of gold adsorption onto a coconut shell- based activated carbon. Equilibrium isotherms were also determined. It is concluded that the homogeneous surface-diffusion model fits the experimental data reasonably well and provides a good balance between simplicity and descriptive accuracy. The model contains two parameters: the extra-particle mass-transfer coefficient and an effective intraparticle surface-diffusion coefficient. Both can be evaluated readily from simple adsorption experiments.

Jan 1, 1991

O.F.S. Branch Proceedings of the Annual General Meeting on Wednesday, 30th July, 1975 The Aromal General Meeting of the Branch was held at the St. Helena Club on Wednesday, 30th July, 1975 at 7.45 p.m. Mr D. A. Smith (Chairman) was in the Chair. There was also present: Professor R. P. Plewman, President of the S.A. Institute of Mining and Metallurgy. Conference on Vacuum Metallurgy The Fifth International Conference on Vacuum Metallurgy is to be held in Munich from 11th to 15th October, 1976. Excavation and tunnelling A conference on 'Rapid Excavation and Tunneling' is to be held in Las Vegas from 14th to 17th June, 1976. Book reviews Mine filling. Queensland (Australia), Mt. Isa Mines, Limited, ] 973. 293 pp. $A20,00 incl. postage. Young, R. S. Cheml:cal phase analysis. London, Charles Griffin, 1974. 126 pp. £4.50. NIM reports Report no. 1714 The efficiency of the fire-assay procedure with nickel sulphide as the collector in the determination of platinum,silver, gold, and iridium. Report no. 1721 A preliminary investigation into the mechanism of depression in the flotation of sulphide minerals at the Prieska Copper Mine. Report no. 1725 The determination of silica in fluorspar by 14 Me V neutron-activation analysis. Report no. 1736 The determination, by atomic- absorption spectrophotometry and liquid extraction, of antimony (parts per million) in ores and concentrates. Report no. 1741 South African costs of equipment for the metall'urgical industry(1975}. Report no. 1744 The refining of the platinum-group metals . Report no. 1746 The determination, by atomic-absorption spectrophotometry, of minor elements in zinc, lead, and copper sulphide concentrates. Report no. 1747 Magnetohydrostatic separation of gold from gravity concentrates. Report no. 1750 A review of the present and future development of sulphur production in South Africa. Report no. 1754 A new three-dimensional anodic electrode for reduced power consumption du,ring the electrowinning of metals. Report no. 139 A preliminary survey of goldrecovery problems arising in the production of pyrite. (9th Feb., 1967, re-issued Jun. 1975.) 16 pp. Report no. 140 A preliminary mineralogical investigation of pyrite from the K imberley and the Main Reefs, VogelstruisbuU Gold Mine. (13th Feb., 1967, re-issued Jut 1975.) 11 pp. Report no. 165 Gold recovery from pyrite flotation mill products by cyanidation. Progress made up to 1st May, 1967. (5th May, 1967, re-issued Jun. 1975.) 8 pp. Report no. 133 Gold recovery by cyanidation from mill products obtained after pyrite flotation. Progress made up to ht July, 1967. (18th Jul., 1967, reissued Jun. 1975.) 14 pp. Report no. 219 A review of some of the mineralogical factors influencing the flotation of pyrite. (29th Nov., 1967 reissued Jun. 1975.) 20 pp. Report no. 278 Gold recovery by cyanidation from mill products obtained after pyrite flotation. (24th Jan., 1968, re-issued Sep. 1975.) 51 pp. Report no. 306 The effect of preaeration on two samples of thickener under flow from the Venterspost Gold Mine. (30th Mar., 1968, re-issued Jul. 1975.) 14 pp. Report no. 317 Results of tests carried out at the Loraine Gold Mine during the period 5th to 7th February, 1968. (21st Mar., 1968, re-issued Jul. 1975.) 11 pp. Report no. 321 Aeration of ore from the Loraine Gold Mine before theaddition of cyanide.(17th Apr., 1968, reissued Jul. 1975.) 30 pp. Report no. 380 The effect of aeration, before cyanidation, of pulps of gold ores containing xanthate. (14th Aug., 1968, re-issued Jul. 1975.) 44 pp.

Jan 10, 1975

By P. G. Terrazas Prado

This paper presents the results of research on the development and application of a custom-made truck cycle and delay automated data collection system (TCD-ADCS) in a surface coal mining. Truck cycle and delay field data are locally stored in trucks and then synchronized and replicated through a wireless network into a centralized server containing an already-developed integrated production management system (IPMS). The system relies on motion sensing and distance travelled in order to automatically define the cycle starting/ending points, cycle time, position, and delay time. Connectivity and communication between loading equipment and trucks are also established. Communication between the equipment operators and TCD-ADCS system is via a user-friendly graphic interface. The hardware used for the development of this system consists of a rugged touch-screen personal computer, 2.4 GHz radio transmitter antenna, and a commercial GPS receiver. The system was developed, tested, and deployed at a surface coal mine in the USA. Keywords surface coal mining, truck and shovel, data collection, information systems.

Nov 1, 2013

By Z. G. He, S. H. Chen, P. Egger

A new model for hollow rock bolts which comprises rock material, hollow bolt material, bolt/rock interface, is developed on the base of the composite element method (CEM). The main advantage of the new model is that it can be incorporated into the conventional finite element analysis. So the mesh generation of bolted rock structures becomes more convenient and feasible, which is very important in the optimisation of reinforcement design: the mesh can be kept unchanged when the number and orientation of bolts are adjusted. The comparison of the calculation results with a conventional FE approach shows the robustness of the proposed method. Un nouveau modèle numérique de boulons creux comprenant la roche, le matériau du boulon creux et l’interface roche / boulon est développé sur la base de la méthode des éléments composites (CEM). L’avantage principal du nouveau modèle est la possibilité de l’incorporer dans une analyse aux éléments finis conventionnelle. Ainsi la génération du maillage d’une structure rocheuse ancrée devient plus simple ce qui est très important pour une optimisation du projet : en cas d’ajustement du nombre et de l’orientation des boulons, le maillage reste inchangé. La comparaison de résultats de calcul avec ceux obtenus par un code aux éléments finis conventionnel montre la robustesse de la méthode proposée. Auf der Grundlage der Verbund-Element-Methode (CEM) wird ein neues Modell für hohle Reibungsanker entwickelt, das den Fels, das Ankermaterial und die Kontaktfläche Fels / Anker umfasst. Der Hauptvorteil des neuen Modells ist die Möglichkeit, es in eine konventionelle FE-Analyse einzubetten. So wird die Netz-Generierung für verankerte Fels-Bauwerke einfacher, was für die Optimierung des Verankerungs-Projekts von Wichtigkeit ist: wenn Zahl und Orientierung der Anker variiert werden, bleibt das Netz unverändert. Der Vergleich von Rechenergebnissen mit solchen aus einer konventionellen FE-Rechnung zeigen die Robustheit der vorgestellten Methode.

Jan 1, 2003

By N. B. Strydom

I have read with interest all the papers dealing with heat transfer and the setting of heat stress limits that have appeared during the past two decades. Scientifically speaking, most of them can be rated as being of a high standard, and some of them have been acclaimed internationally as masterpieces of logical and calculated reasoning. Weathering of ore minerals A short course on 'The Weathering of Ore Minerals and the Textural Evaluation of Base Metal Gossans' is to be given by Dr I.M. Reynolds in Grahamstown from 4th to 6th October, 1982.

Jan 1, 1982

By M. Rudolph, E. Schach

Tecflote is a new group of nitrile-based collectors for sulfide flotation. Water insolubility results in some interesting implications for the actual mechanism. It is not yet understood if Tecflote is directly adsorbed on the mineral surface as emulsion droplets or if it is only active at the air-water interface, affecting the interfacial rheology or electrostatic- and Van der Waals interactions, which have a direct impact on the bubble-particle contact. Different investigations including contact angle measurements, AFM studies and micro-flotation experiments are conducted to obtain a better understanding of the actual mechanism of Tecflote. Due to the reagent’s insoluble character, the Langmuir-Blodgett technique is used to investigate its behaviour in the air-water interface and to deposit defined layers of Tecflote on mineral substrates for the above-mentioned studies. An interferometric set up is used to investigate the influence of Tecflote on the film thinning between an air bubble and a mineral substrate. In addition, possible synergistic effects for the combination of Tecflote and conventional frothers (e.g. MIBC) are studied. Keywords: Sulfide flotation, insoluble collector

Jan 1, 2020

By W. Soetaert, P. Dhar, H. R. Kota, M. Thornhill, S. Roelants, I. V. Chernyshova

Yeast-derived bola-amphiphiles have attracted considerable attention for their applications in various industrial sectors in recent years. However, only a few studies on this class of surfactant were reported to be relevant to mineral processing applications. In this paper, one of the novel surfactants, acidic glucolipid obtained from Candida bombicola sophorolipids and modified by using Penicillium decumbens naringinase substrate has been evaluated for its interaction with chalcocite and calcite minerals because of a new Cu-ore Nussir deposit in Norway containing calcite impurity. The interaction of glucolipid biosurfactant with copper sulphide and carbonate minerals was investigated with zeta potential, adsorption and FTIR studies, and also by Hallimond tube and bench scale flotation tests using pure minerals and Nussir copper ore, respectively. The results illustrate collector adsorption and flotation of copper sulfides at neutral pH. The bench-scale flotation results demonstrate that copper sulphides can be selectively floated from carbonate and silicate gangue minerals. This study underlines the glycolipid’s high potential for its use as collector for flotation of valuable copper sulphide minerals. Keywords: Flotation, biosurfactants, adsorption

Jan 1, 2020

By A. M. Sage

This paper reviews the metallurgical functions of vanadium in high-strength Iow-alloy steels, and discusses the ways in which vanadium is used in various types of steel supplied as reinforcing bars, plates, sections, and strip. Potential developments to meet new engineering requirements are discussed briefly.

Jan 1, 1984

By M. Gholinejad

Applying non-explosive expansion material (NEEM) is one of the safest methods for rock fracturing, especially in a hard rock quarry. An experimental study was conducted to determine the pressure exerted by NEEM in a hole, which is necessary for analysing rock fracturing, particularly in a numerical modelling. Stress distribution was developed in a thick-wall cylinder in order to measure the tangential strain on the external boundary. In the experiments, nine pipes of different materials and varying diameters were selected and then loaded internally with a general type of NEEM. Through electrical strain gauges, the tangential strains were recorded on the external boundary of the pipes. The results obtained from these tests and existing data from previous researchers were utilized for the statistical analysis. A new experimentally-derived formula is proposed for determining the pressure exerted by NEEM by multiple parameter regression with a high correlation coefficient. The proposed model has a nonlinear form with three independent parameters i.e. the hole diameter, the time, and the modulus of elasticity of the material.

Jan 1, 2012

By M. Gholinejad

Applying non-explosive expansion material (NEEM) is one of the safest methods for rock fracturing, especially in a hard rock quarry. An experimental study was conducted to determine the pressure exerted by NEEM in a hole, which is necessary for analysing rock fracturing, particularly in a numerical modelling. Stress distribution was developed in a thick-wall cylinder in order to measure the tangential strain on the external boundary. In the experiments, nine pipes of different materials and varying diameters were selected and then loaded internally with a general type of NEEM. Through electrical strain gauges, the tangential strains were recorded on the external boundary of the pipes. The results obtained from these tests and existing data from previous researchers were utilized for the statistical analysis. A new experimentally-derived formula is proposed for determining the pressure exerted by NEEM by multiple parameter regression with a high correlation coefficient. The proposed model has a nonlinear form with three independent parameters i.e. the hole diameter, the time, and the modulus of elasticity of the material.

Jan 1, 2012

Dr Andrew Cosgarea, Jr, Associate Director of Opera¬tions of the U.S. Mint, and Chairman of the Awards Committee of the International Precious Metals Institute, announced the IPMI award recipients for 1985. The awards were presented at the Institute's Annual Banquet in New York City on 11th June, 1985. The Distinguished Achievement Award was presented posthumously to Dr E.M. Savitsky, of the A.A. Baikow Institute of Metallurgy of the U.S.S.R., for a life-time career devoted to investigations on the properties of the platinum-group metals. Dr Savitsky investigated over 300 phase diagrams, which became the basis for the selection of alloys and the prediction of properties. He published over 300 technical papers during his career. Dr Savitsky died during the summer of 1984 while being considered for the IPMI Award. The Engelhard Henry J. Albert Award was presented to Dr Stephen J. Lippard, Professor of Chemistry, MIT, in recognition of his research contributions in platinum chemistry and its application to nucleic acids. This prize

Jan 1, 1985

By G. R. W. Walker

A unique means of obtaining sea-water by G. R. W. WALKER, Pr. Eng., B.Sc. (Hons.) (Min. Eng.) (Member) Although the mining and treatment operations at The Consolidated Diamond Mines of South West Africa, Limited, are located within an average distance of I km from the Atlantic Ocean, the supply of clear sea-water in large and continuous quantities for use in treatment plants is made difficult by siltation of water-holes and the amount of sand in suspension in the sea itself. The need for sixty million litres of sea-water per day at the new No. 2 treatment plant necessitated the construction of a system that would ensure a continuous and reliable supply. Several sea-water intake schemes were proposed. This paper outlines the need for an improved means of obtaining water and describes the construction of the scheme eventually chosen - a tunnel driven through bedrock for over 400 m beneath the Atlantic Ocean. At the end of the tunnel, two large chambers were excavated from which vertical holes were drilled to intersect the sea-bed.

Jan 5, 1976

By B. Geelhoed

Gy's formula for the variance of the fundamental sampling error (FSE) is based on a model that assumes independent selections of particles. A generalization of this model, which can theoretically lead to more realistic representation of actual sampling processes, was, for the first time, experimentally verified by repeated sampling from a well-mixed batch consisting of particles of zirconium silicate of two different sizes. The predictions for the sampling variance made in Gy?s theory and in the more general model were compared with the experimentally observed sampling variance. During the experiment performed here, the variance prediction made in the theory of Gy ranges from 0.96 × 10?7(g2/g2) to 0.95 × 10?7(g2/g2), which is approximately a factor 60 lower than the experimentally observed variance (5.76 × 10?6(g2/g2)). The difference between the Gy prediction and the experimentally observed variance cannot be fully explained by the uncertainty in the experimentally obtained variance due to the finite number of degrees of freedom. Therefore, the difference is likely to be a significant effect. This shows that, under the experimental conditions, Gy?s formula for the variance of the FSE probably undervalues the sampling variance, unless an empirical correction factor for grouping and segregation is applied in the theory of Gy. The new theory resulted in a variance prediction of 6.00 × 10?6(g2/g2), which is much closer to the observed variance than the Gy prediction. This indicates that the generalization of Gy?s theory offers an outlook for providing a better variance prediction than the Gy predictor in the case of dependencies between particle selections. The results are discussed. Keywords: sampling, variance, parameter for the dependent selection of particles, Gy, experiment.

Jan 1, 2009

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