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By R. Guest

Reichert cone concentrators are used successfully in many applications, but have as yet not found favour in the gold mining industry on the Witwatersrand, because, for optimum operation, the cones need to have specially designed feed-preparation and circuit details. In addition, good liberation of the valuable minerals is essential. Gravity tests, in which a pilot plant was used on refractory gold ore, showed that 94 per cent of the gold could be extracted after gravity concentration and preferential grinding, roasting, and cyanidation of the concentrate, whereas 96 per cent could be extracted by flotation followed by the same preferential treatment. However, the capital and operating costs for gravity separation are expected to be considerably lower than those for flotation.

Jan 1, 1982

By G. S. Bartlett

The theme of this Colloquium, survival strategies, not only conveys a sense of urgency but also takes cognizance of the fact that, as in the political arena, tough decisions have to be made and acted upon in the years to come. It is therefore appropriate that the SAIMM, as spokesman for the metallurgical industry, should be dealing with these issues at this time, and I wish to commend the organizers of this Colloquium for focusing on a mater as important as the future of this great industry. In view of this, I regard it as an honour and privilege to officiate on this occasion, where the best of South Africa's brain power in the metallurgical field will be harnessed with a view to moulding strategies for survival.

Jan 1, 1993

INTRODUCTION The SAIMM publishes technical information on various aspects of the minerals industry through several different media. (a) Monograph Series Books in the Monograph Series are high quality, detailed discussions on specialized topics. (b) Symposium Series This series consists of the proceedings of international conferences which are held in South Africa. (c) Special Publications Series This series covers titles which do not form part of the Monograph and Symposium Series. (d) The SAIMM Journal Papers published in the Journal cover al relevant areas of technical interest by striving for a balanced content and maintaining a consistently high technical standard. (e) School and Colloquia Notes The papers from al local schools and colloquia are published and handed out at registration. Should authors wish to have their papers considered for publication in the Journal, they should adhere to the guidelines outlined below.

Jan 1, 1991

By D. J. van Niekerk

Caring for the Earth: South Africa-A strategy sustainable living, by John Yeld. Southern Foundation in partnership with the World Union. Soft cover. Tel.: (02231) 72801.

Jan 1, 1993

The winners of the Delfos and Atlas Copco Travel Grant for Mining Engineers were announced at a cocktail party hosted by Mr Mario Pellegrino, Managing Director of Delfos and Atlas Copco, at the Sandton Sun Hotel on Friday evening, 18th May, 1984.

Jan 1, 1984

By R. H. English, N. C. Joughin

The results of trials with three stope-face cleaning systems are described. Two of these systems were based on armoured chain conveyors, and the third on a reciprocating-flight conveyor. The operational elements of each system are discussed with reference to their effectiveness, and many problems are highlighted. It is concluded that the reciprocating-flight conveyor is superior, and has the potential for being developed into a system yielding a labour productivity of more than 30 m2 per worker per month and a face advance of 15 m per month working one shift a day.

Jan 1, 1979

By G. Poropat, A. R. Guest, H. P. Grobler

At the De Beers Consolidates Mines operations it is common practices to perform Geotechnical mapping of the newly exposed faces in the waste and ore rock. The purpose of Geotechnical mapping is to quantify the in-situ fracturing of a rockmass that in turn is required during the planning and application of a mining method. Whether it is to determine slope angles, caveability, impact of blasting or support requirements. This mapping involved a cumbersome and time consuming procedure that requires individual examination and description of the natural inherent fractures exposed by mining. During highwall mapping in an open pit this can be a safety concern due to the duration of time spent below a highwall. The advantages gained through the recent introduction and application of SiroVision® allows safer mapping, an increase in statistical fracture population, archiving of rock faces and the more accurate reflection of the true mapping. This paper aims to describe in detail the application of the recently developed SiroVision®, photogrammetry software, to replace conventional face mapping. A De Beers Consolidated Mines, il est pratique courante de faire une cartographie géotechnique des tailles récemment exposées dans le rocher stérile ou minerai. Le but de la cartographie géotechnique est de quantifier la fracturation in-situ d’une masse rocheuse, qui sera nécessaire lors de la planification et application d’une méthode minière, que ce soit pour déterminer les angles des galeries inclinées, les possibilités de foudroyage, l’impact du dynamitage, ou les besoins en supports. Cette cartographie nécessitait une procédure longue et compliquée qui demande l’examen individuel et la description des fractures naturelles propres exposées par l’opération de mine. Pendant la cartographie de parois dans une exploitation à ciel ouvert, cette opération peut être dangereuse à cause du temps passé sous la paroi. Récemment, le lancement et application de Siro Vision apportent l’avantage d’une cartographie plus sûre, une augmentation des statistiques de population de fracture, l’archivage des tailles de roches, et le reflet plus précis de la cartographie. Le but de l’étude présente est de décrire en détail l’application du développement récent de Siro Vision, logiciel de photogrammétrie, pour remplacer la cartographie de taille conventionnelle. Bei den De Beers Consolidates Mines Operationen ist es gängige Praxis geotechnische Aufzeichungen des Taub- und Erzgesteins neu geöffneter Abbaustellen zu erstellen. Zweck dieser geotechnischen Aufzeichnungen ist die vor-Ort-Quantifizierung des Bruches der Gesteinsmasse, welche im Gegenzug während der Planung und der Anwendung einer Abbaumethode erforderlich ist, sei es um einen Neigungswinkel festzustellen, Abbaubarkeit, Auswirkung von Sprengungen oder Anforderungen an Unterstützungen. Die Aufzeichnungen waren mit umständlichen und zeitaufwendigen Prozeduren verbunden, die eine individuelle Prüfung und Beschreibung der durch den Abbau freigelegten natürlichen inhärenten Brüche, verlangten. Dies kann auf Grund des Zeitraumes der unterhalb einer Flözoberschicht verbringt wird zu einer Frage der Sicherheit werden wenn die Aufzeichnung einer Flözoberschicht im Tagbau erfolgt. Die Vorteile auf Grund der jüngst erfolgten Einführung und Anwendung der SiroVision® gestatten sichereres Aufzeichen, eine Zunahme in der statistischen Menge an Gesteinsbrüchen und eine akkuratere Reflektion der tatsächlichen Aufzeichnungen. Diese Arbeit hat zum Ziel im Detail die Anwendung der kürzlich entwickelten SiroVision®, eine photogrammetrische Software, die die konventionelle Abbauortaufzeichnung ersetzen soll zu beschreiben.

Jan 1, 2003

By N. du Preez, J. Christie, F. Crundwell

Precipitation is a key process in the recovery of copper and cobalt. While there is a wealth of experience in operating precipitation steps, improving their performance remains challenging. Chemically, the reaction might be controlled by reaction kinetics, be limited by oxygen mass transfer, or be at equilibrium. In this paper, we examine these different operating regimes and demonstrate how they can be identified from plant operating data, process modelling, and pilot plant test work

Jan 1, 2023

Book Review Gold Metallurgy in South Africa, edited by R. J. Adamson and published by the Chamber of Mines of South Africa, Johannesburg, 1972. The metallurgical processes used for the recovery of gold from Witwatersrand ores were first described in A Text Book of Rand Metallurgical Practice, published in 1912 and subsequently revised in 1926. This was followed by Gold M etall1trgy on the Witwatersrand by A. King in 1949. New Publications Elements of Practical Coalmining, S. M. Cassidy (editor), New York, Society of Mining Engineers of AIME, 1973, $16.50. Future Enerey Outlook, J. A. Pederson (editor), Colorado School of Mines Quarterly, vol. 68, no. 2, April 1973, $6.00. Guide To The Preparation Of Papers For Publication In The Journal Of The South African Institute Of Mining And Metallurgy 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.

By T. Könighofer

Processing of copper-cobalt orebodies in Africa?s Copper Belt has received much recent attention with various flowsheet options being developed specifically for the refining of cobalt. The upfront leach and copper refining routes are well understood whereas the refining of cobalt is more complex, requiring numerous impurity removal steps to produce high purity metal. This paper describes an investigation into one of the possible processing steps in the refining of cobalt, namely, cobalt solvent extraction. The paper emphasizes the importance of upstream impurity removal to achieve the required cobalt solvent extraction feed composition. 18% (v/v) Cyanex 272 in an aliphatic diluent is used as the organic phase. The pH profiles in the various stages are evaluated in order to obtain a raffinate containing <10 mg/[l] cobalt and with a low magnesium content reporting to the stripping section. The pH profile is also used to minimize the impurity deportment to the cobalt electrolyte. The effect of adding a preneutralization stage before feeding the organic phase to the extraction circuit is investigated. Zinc build-up in the stripping stages is also looked at. It is recommended for the purpose of this study that four extraction stages at an O:A ratio of 1 with a pH profile from 4.9 to 5.7 be employed. The pH is controlled with 40 g/[l] NaOH. A preneutralization stage is required, where the organic phase is contacted with 10 M NaOH. Two scrubbing stages are recommended at an O:A ratio of 40, using the cobalt electrowinning advance electrolyte as the scrub liquor. Three strip stages are to be employed at an O:A ratio of 0.67.

Jan 1, 2009

O.F.S. Branch Proceedings of the Annual General Meeting Held on Wednesday, 4th August, 1976 Mr G. J. C. Young (Chairman) was in the Chair. Also present was Dr R. E. Robinson, President of the South African Institute of Mining and Metallurgy. NlM reports Report no. 175 Copper extraction by leaching magnetites from Palabora Mining Company. (12th Apr., 1967; re-issued Jun. 1976) Report no. 1632 A mineralogical examination of beach-sand concentrates from a pilot plant at Richards Bay. (20th May, 1974; re-issued Jun. 1976.) Report no. 1825 The full automation of a Philips 1220 X -ray spectrometer. A Philips 1220 X-ray spectrometer (semi-automatic) Report no. 1840 The spectrophotometric determination of total uranium in silicate ores and leach liquors by use of bromo-PADAP. Report no. 1841 The determination of aC1;d-soluble uramum in silicate ores and solutions. AS & TS National Award The Associated Scientific and Technical Societies of South Africa has decided to make two National Awards this year. These awards, given in recognition of outstanding contributions to science and the application of science, will be made to Dr T. L. Wadley for his invention of the Tellurometer system of distance measurement and to Mr H. Scheffel for his design of the High Stability Bogie. Treatment of waste water A major international symposium, organized jointly by the Water and Environment Group of the Society of Chemical Industry and the Environment Group of The Chemical Society of London, will be held in London in 1977. Down-the-hole drilling Atlas Copco announces the publication of a revised and enlarged version of one of the booklets in their series &apos;Mining and Construction Methods&apos;. This 40-page booklet is entitled &apos;Down-the-hole drilling with COP drills&apos;.

Jan 10, 1976

By G. Dhakal, J. -I. Kodama, K. Neaupane, T. Yoneda

ABSTRACT Durability tests and evaluation of sub-zero temperature effects to some argillaceous clastic rocks were carried out. Welded tuff, limestone, sandstone and schist samples collected from different parts of Japan were tested and results are presented. Schist and dolomite from Ganesh Himal area along the higher Himalayas of Nepal were also tested, and the results are compared. The slaking tests were performed on all samples in pure water. The results reveal that the slaking index of schist from Japan is lower than that of schist from Nepal. Regarding carbonate rocks, the slaking index of limestone from Japan is higher than that of dolomite from Nepal. A tendency of decrease in slake durability with an increase in porosity is also observed. Freezing and thawing experiments conducted on welded tuff and schist reveal that crack initiates earlier but extends slower in schist than in welded tuff. It is also observed from the freeze-thaw experiment that the welded tuff deteriorates and wears faster than the schist. However, sandstone remains relatively intact for a long run of freeze-thaw cycles. Zusammenfassung Beständigkeitstests sowie die Bewertung der Auswirkungen von Minusgraden auf Tonschiefer Trümmergestein wurden durchgeführt. Dabei wurden geschweißter Tuff, Kalkstein, Sandstein und Schiefer aus verschiedenen Gebieten Japans sowie Schiefer und Dolomitgestein aus dem Ganesh Himal Gebiet, dem höheren Himalaya Nepals, untersucht und die Resultate verglichen. Für alle diese Gesteine wurden Slaking-Tests in reinem Wasser vorgenommen. Die Resultate zeigen, dass das Slaking von Schiefer aus Japan höher als das von Schiefer aus Nepal war, wohingegen bei kalkhaltigem Gestein das Slaking von Kalkstein aus Japan niedriger als das von Dolomitgestein aus Nepal ausfiel. Es wurde dabei auch eine Tendenz zur Löschbeständigkeitsverringerung bei gleichzeitig erhöhter Porosität beobachtet. Gefrier- und Tautests an geschweißtem Tuff und japanischem Schiefer zeigten, dass Risse in Schiefer schneller auftraten, aber sich langsamer ausweiteten als in geschweißtem Tuff. Bei Gefrier- und Tautests wurde ebenfalls beobachtet, dass geschweißter Tuff schneller verfällt und verschleißt als Schiefer. Sandstein hingegen blieb über lange Tau- und Gefrierzyklen intakt Résumé Des tests de solidités et l’évaluation de l’effet des températures en dessous de zéro sur les rocs argileux ont été effectués. Les rocs d’origine volcanique (cendre), les rocs calcaires, sableux et les schistes de différentes régions du Japon, ont été étudiés. Les schistes et les dolomites de la région de Ganesh Himal le long du haut Himalaya (Népal) ont été étudiés et comparés à ceux du Japon. Les tests de désintégration sur les rocs ont été effectués dans l’eau pure. Les résultats montrent que l’index de désintégration des schistes du Japon est inférieur aux schistes du Népal. En ce qui concerne les rocs carbonyles, l’index de désintégration des rocs calcaires du Japon est supérieur à ceux des dolomites du Népal. Une décroissance de la résistance à la durabilité est observée avec une plus grande porosité des rocs. Les tests de congélation-décongelation sur les schistes et les rocs d’origine volcanique (cendre) du Japon montrent une apparition précoce des fissures mais l’expansion des fissures est plus rapide dans les rocs volcaniques. Des tests similaires montrent que les rocs volcaniques (cendre) se désagrégent plus rapidement que les schistes. Cependant, les rocs sableux restent intacts après plusieurs cycles de congélation-décongélation.

Jan 1, 2003

By Gordon Chunnett, Ron Sheets, David Grant

[Power-Point Presentation]

Jan 1, 2005

By D. Bessinger, N. Rughubir

Exxaro Sands KZN produces?among other heavy mineral products?high titania slag, which is used as feedstock to the pigment industry. The titania slag is produced from the smelting of ilmenite in two 36 MW DC furnaces. In this smelting process carbon monoxide gas is produced. This gas is cooled, scrubbed and washed to remove entrained dust. This paper provides details on the gas cleaning plant system and the chemistry, mineralogy and size distribution of the particulate material contained in the off-gas stream. Characterization of the dust shows that is consists mainly of ilmenite, but with relatively high levels of SiO2and MnO. Smelting of the dust in a 500 kW DC furnace was carried out to investigate the potential for recovering valuable elements from the dust.

Jan 1, 2007

By W. P. C. Duyvesteyn, J. R. Cutland, J. R. L. Russell

In 1970 it was decided to build a large new plant at the Chingola Division of N.C.C.M., Ltd., to treat concentrator tailings and leach residues with a low copper content by a leach-solvent extraction-electrowinning process. In order to assist in the establishment of the design parameters for the new plant, and to study the interaction of this plant with the existing leach-electrowinning plant, mathematical models, formulated as linear programs, have been developed and used extensively. The paper outlines the metallurgy of the plants and describes briefly the way in which the models have been formulated and used. The formulation involved the use of separable programming to form the products of some variables.

Jan 1, 2014

By A. J. Burger, F. L. D. Cloete

Tests indicated that effective recovery of pyrite from a coarse Witwatersrand quartzitic ore can be accomplished by intensified flotation in an air-sparged hydrocyclone. Air is fed through the porous cylindrical wall of the hydrocyclone into a swirling layer of slury. Hydrophobic particles are attached selectively to small air bubbles, which form a froth and are recovered through the overflow. Hydrophilic particles pass out in the underflow. A spigot in which flow is restricted by an orifice was found to be more successful in preventing blockage by wood chips than an annular opening between a pedestal and the cylinder wall. Pyrite recoveries of 85 to 93 per cent at grades of 35 to 40 per cent sulphur were obtained in the air-sparged hydroclone with residence times of about 1 second. Comparative tests in a batch flotation cell after 320 seconds yielded average recoveries of up to 96 per cent, but with a mean grade of 32,5 per cent sulphur. A high colector dosage of 120 g/t was required in the cyclone, compared with the 40 gft used in conventional operations. An air flowrate of about 150 I/min was adequate at a slury feed rate of 35l/min. Particle sizes between 38 and 106µm yielded the best flotation results.

Jan 1, 1988

By H. S. Sichel

Statistical valuation of diamondiferous deposits By H. S. SICHEL, D.Sc The valuation of diamondiferous deposits depends on (i) the density distribution, (ii) the size distribution of stones and (iii) the selling price structure prevailing at a particular time. In the density distribution the stochastic variable is defined as the number of individual stones found per sample unit irrespective of the stone size. The density distribution is discrete and allows for barren sample units. As diamonds often occur in clusters, a Poisson mixture distribution is derived which is entirely new, as existing discrete distributions cannot represent the stone number frequencies found in nature. For the sizes of diamonds, which are measured by weight, a new compound logarithmic normal distribution is developed. Combination of (i), (il) and (iii) leads to a meaningful appraisal of diamondiferous ground expressed in monetary value per production unit of mining. Finally, confidence limits are calculated which allow for inferences from sampling to recovery.

By Kevin Peacocke

The future of Gravity ? Primary mineral recovery ? Enhancement of existing process efficiency ? Pre-Concentration ? Alternative? or ?New? production

Jan 1, 2006

By C. R. S. Needes, M. J. Nicol, G. T. W. Ormrod, N. P. Finkelstein

The industrial application of a dioxide electrode uranium by C. R. S. NEEDES, Ph.D. (London) (Visitor), M. J. NICOL, Ph.D. (Rand) (Visitor), N. P. FINKELSTEIN M.Sc. (Rhodes), Ph.D. (Liverpool) (Fellow), and G. T. W. ORMROD (Visitor) A correlation between the potential of a U02 electrode and the rate of recovery of uranium has been proved in laboratory and plant trials. When the recovery rates change because of variation in the concentrations of Fe(III), Fe(II), SO4 &apos;and H+, a positive correlation is observed. However, an 2- increase in the concentration of phosphate in solution produces an increase in the U02 electrode potential but a decrease in the rate of leaching of U02. The correlation between the U02 electrode potential and the rate of leaching of U02 is then negative. It is concluded that, as a control device, the electrode cannot compete with the platinum electrode for use on certain plants. Nevertheless, the U02 electrode will act as a useful warning device if the total concentration of iron in solution decreases to below a level concomitant with the economic recovery of uranium. Furthermore, because of the positive correlation between the U02 electrode potential and the phosphte concentration, the electrode will also be of value in the detection of an increase in the phosphate level in solution. When it was incorporated in a suitable industrial probe, the electrode was found to be able to withstand the rigours of the leaching conditions in a large pilot-plant pachuca, and only failed after six weeks&apos; operation.

Jan 11, 1975

By D. L. Morrison

The School on the Accounting for Gold, which was organized under the auspices of The South African Institute of Mining and Metallurgy by Dr Hugh E. Bartlet, Consulting Metallurgist of Johannesburg Consolidated Investment Company Limited, was held at the South African Nature Conservation Centre at Delta Park, Johannesburg, on 15th to 17th May, 1989. It was attended by 178 delegates, including 2 from the OK and 4 from Zimbabwe. A total of 19 papers were presented covering the components of gold-accounting procedure, sampling techniques, and new sampling technology.

Jan 1, 1989