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By A. Koursaris, Y. Turan

The object of this study was to investigate the i1Jfluence of nitrogen on the structure and properties of AISI 310S steel. Experimental ingots of the steel with nitrogen contents of up to 0,525 per cent by weight were prepared, hot-rolled, and tested after various treatments. The rollability of the material was adequate. The yield strength, tensile strength, hardness, and fatigue properties of the new alloys improved with increasing nitrogen content. The impact properties improved slightly. Empirical equations were developed for the calculation of the yield and tensile strengths, as well as the difference between these two properties, with increasing nitrogen content.

Jan 1, 1995

By J. Gilliland

The Grootegeluk coal-beneficiation plant was erected in the Waterberg coalfield, near Ellisras in the Transvaal, to supply Iscor's steelworks with a predetermined tonnage of coking coal in accordance with strict quality requirements. This plant has to handle a high tonnage of raw coal, which is not easy to beneficiate, in order to produce 1,82 X IQ6t of coal. Extensive tests were conducted on borehole cores and a mass sample of coal obtained from the area. These tests were carried out on a laboratory and pilot-plant scale, and were aimed at the establishment of the most effective beneficiation methods and the choice of suitable equipment. This led to the completion of a full set of design and manufacturing drawings that resulted in the project approach . described in this paper.

Jan 1, 1982

VISIT TO HENDRINA POWER STATION AND OPTIMUM COLLIERY A visit to Hendrina Power Station and the Optimum Colliery, contractually committed to supply the coal for the power station, took place on the 20th September, 1972. INTERNATIONAL IRON AND STEEL CONGRESS This congress will be held in Dlisseldorf from May 23rd to 30th, 1974. The main theme is "Metallurgical Technology of Iron and Steplml1king".

By A. K. Haines

Hydrometalurgy, particularly leaching, is a highly topical subject and always generates great interest in the mineral industry. This was evident right from the start of the organization of the SAIMM Colloquium on Leaching, which was held at Mintek on the 8th and 9th November, 1988. The response to the cal for papers was so good that the Colloquium was extended to two days, instead of the usual one day.

Jan 1, 1988

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House on Wednesday, 23rd August, 1978. Mr P. A. von Wielligh (President) was in the chair and declared the meeting open at 16h00. Obituaries The President: It is my sad duty to announce the death of the following members of the Institute : T. K. Prentice and W. E. Gooday, Honorary Life Fellows and Past Presidents; B. S. Allen, J. A. Becking, L. H. Mellor, C. A. Pratt and W. T. Stobart, Life Fellows; J. P. Burls, E. Cameron, M. L. Fitzgerald, C. G. Hinds, A. J. Patrick, H. O. Reisener, N. D. Shuttleworth, N. Soldan and J. Whitehouse, Fellows; T. Gemmell, J. S. A. Oelofse, W. D. Rowe, R. L. J. Shearman and G. M. Thain, Associates. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I ask you to rise and observe a few moments' silence. Welcome The President: It is now my very pleasant duty to welcome our distinguished guests and visitors. We are pleased to have with us Mr D. A. Etheredge, Vice¬President of the Chamber of Mines of South Africa, and Mrs Etheredge. Mr Etheredge this afternoon represents the mining industry at our meeting. The importance of the close link that over the years has been maintained between the industry and our Institute speaks for itself. We are, therefore, grateful that he and Mrs Etheredge have managed to find the time to be with us this after¬noon.

Jan 1, 1979

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

By J. H. Bulloch

This paper describes detailed fractographic analyses of several specimens that had undergone corrosion-fatigue tests at high stress ratios in simulated pressurized water-reactor environments. The distribution and morphology of non-metallic manganese sulphide inclusions are shown to strongly affect the growth of environmentally assisted cracks (EAC), and certain features suggest that a hydrogen-assisted mechanism is responsible for the observed EAC growth. The incidence of transient EAC growth in isolated regions suggests that the critical conditions that trigger this type of growth are the 'right' local chemistry at the crack tips and imposed mechanical conditions.

Jan 1, 1987

By H. W. Glen

In the hope of finding out what the readers of the SAIMM Journal want of our Journal, we sent out a questionnaire with the October 1979 issue. The 2500 copies of the questionnaire sent out elicited 228 responses, which represents a return of 8,8 per cent. The number of responses received from overseas was 24, i.e., approximately 10 per cent of the total. The following is an analysis of the responses received.

Jan 1, 1980

By J. H. Tonking, O. H. Kuschke

A description is given of the general geology, structure and minerals of economic significance of the Loolekop copper orebody at Phalaborwa. The open pit mining method is described with details of drilling, blasting, loading, hauling and primary crushing operations. A brief description is given of mine planning and its relationship to the control of the mining operation.

By T. Aoki, Y. Maeno, R. Kawano, F. Nakahara, Y. Obara, K. Shibata

The mechanical behaviors of fully-grouted long-embedded cablebolts actually used in situ are very non-linear in pull tests and are different from those of short-embedded cablebolts. We have conducted the pull tests of long-embedded cablebolts installed in mockup rock test blocks, which are 4m in the longitudinal length. In order to investigate the mechanical behaviors inside the test block, the axial load distribution along the cablebolt and locations of acoustic emission events were measured during each pull test. It was found that the axial force distributions were quite linear and that the gradients were interpreted as the grout bond strength by taking into consideration the stress balance at the infinitesimal segment of a cablebolt. Les boulons-câbles longs entièrement cimentés qui sont réellement utilisés sur place présentent, au cours des essais de traction, des comportements mécaniques considérablement non linéaires et différents de ceux des boulons-câbles courts. Nous avons mené des essais de traction des boulons-câbles longs installés dans une maquette de fond rocheux servant d’éprouvette d’une longueur longitudinale de 4 m. Afin d’étudier les comportements mécaniques intérieurs de l’éprouvette, la répartition de la force axiale du boulon-câble et l’émission acoustique ont été mesurées durant chaque essai de traction. Il s’est avéré que les répartitions de la force axiale sont sensiblement linéaires et que leurs gradients représentent la résistance d’adhésion en prenant en compte l’équilibre de contraintes à la partie infinitésimale d’un boulon-câble. Das mechanische Verhalten von ganz eingegossenen, lang eingebetteten Kabelbolzen, die vor Ort eingesetzt werden, ist bei Zugprüfungen sehr nichtlinear und anders als das von kurz eingebetteten Kabelbolzen. Es wurden Zugprüfungen mit lang eingebetteten Kabelbolzen durchgeführt, die in Prüfblöcken (Gesteinsattrappen) mit 4 m Länge eingelassen waren. Zur Untersuchung des mechanischen Verhaltens in den Prüfblöcken wurden die Axiallastverteilung entlang des Kabelbolzens sowie das Auftreten von Schallemission im Verlauf jeder Zugprüfung gemessen. Es ergab sich, dass die axiale Kraftverteilung recht linear ist, und die Gradienten wurden unter Berücksichtigung des Kräftegleichgewichts am infinitesimal kleinen Punkt eines Kabelbolzens als Haftfestigkeit interpretiert.

Jan 1, 2003

By J P. van Dyk

The dramatic strengthening of the rand against the dollar as well as a decline in quantity and quality of locally available concentrates have had a dramatic impact on Zincor?s operations during the previous two years. Zincor has responded with the implementation of a number of technical improvements to the process to decrease cost and increase revenue and plant flexibility. Among the initiatives is the pre-leaching and pelletising of the zinc concentrate, de-bottlenecking and process improvements in the leach and purification circuits, the introduction of cathode washing and automated cathode stacking in the cell house and the installation of a new furnace to produce pre-alloyed jumbos. This paper will describe these initiatives and others that Zincor have recently taken to stay competitive in changing global base metals market.

Jan 1, 2005

By B. K. Loveday

There are certain ores that can be treated without upgrading (e.g., gold and uranium ores), and upgrading needs to be considered only for fairly low-grade ores of this type. If the grade is very low, treatment will not be economic even with upgrading, and there is therefore a limited range of ore grades for which upgrading is suitable.

Jan 1, 1980

Visit to Premier (Transvaal) Diamond Mining Company Limited On the 14th February, 1973, 44 members of the Institute were the guests of Premier (Transvaal) Diamond Mining Company Limited. Metrication News PRESSURE GAUGES There appears to be doubt in some circles about the general acceptance of the pascal (Pa) as a unit of pressure and stress. NATIONAL INSTITUTE FOR METALLURGY / NASIONALE INSTITUUT VIR METALLURGIE REPORT. VERSLAG No. 1430 THE USE OF THE EKCO MINERAL ANALYSER FOR THE DETERMINATION OF COPPER AND ZINC IN THE PRESENCE OF IRON 27th June, 1972 Investigator: Gisela Domel SYNOPSIS The Ekco Mineral Analyser-a portable, radio-isotopic X-rayfluorescence instrument-is briefly described,

By M. J. Daly

Historically, engineers and scientists, particularly those involved in the coal-mining industry, have been slow to adopt statistical methods. However, the need to obtain the maximum information .from expensive exploration and development programmes, and the current focus on total quality management, have led to a change in perceptions if classical statistical and geostatistical methods and their application as planning tools. Some if the underlying issues associated with the generally poor communications between statisticians and engineers/physical scientists, which contribute to some if the misconceptions relating to statistical methods, are discussed The potentially profitable application if a number if statistical techniques in the fields if geological evaluation and mine planning! development is also reviewed, with specific reference to the coal industry.

Jan 1, 1995

By I. Wayland

Value added blasting is a process methodology that links tasks and processes, with the aim to improve/enhance the technical application of explosives technology and initiating systems, resulting in improved output. The phases and steps of a typical value added blasting intervention are discussed in this paper. Each step having distinct purposes, principles and methodology. The underlying philosophies and process steps of the programme are described for each step. This paper gives an account of projects that have been completed in two Anglo American Gold Mines. This will include a description of the projects that were conducted at Vaal Reefs 8 Shaft and Western Deep Levels South Mine covering: ? The need for blasting improvements ? The approach that was followed ? The result of the programme.

Jan 1, 1999

By Nareetsile S., J. Kabwe

In the past few years Orapa and Letlhakane Mines have investigated various new technologies to enhance and improve production. The goal has been to improve productivity, reduce operating costs and make the mines more profitable The advent of Global Positioning Systems (GPS) in the early ’80s brought about the realization of this concept. Orapa and Letlhakane Mines started using GPS in 1999 and it is now used atLetlhakane mine for surveying, vehicle tracking and dispatching and for floor control system. Orapa Mine uses GPS in surveying, floor control and drill navigation. It will also be used for vehicle tracking and dispatching in mid-2001 following the installation of a fleet management and control system. The introduction of GPS at both Orapa and Letlhakane mines have improved productivity and reduced operating costs in the areas of drilling, topographic survey and floor control. In vehicle tracking and dispatching GPS has allowed for real-time information management for timeous decision-making which optimized fleet run time hours.

Sep 1, 2001

By K. M. Banks

The hot ductility of in situ melted tensile specimens of micro-alloyed steels having C contents in the range 0.12?0.17% (mass %) have been examined over the 700?1000°C temperature range. An improved testing method for simulating the continuous casting process was used, which takes into account both primary and secondary cooling conditions. Increasing the N content to electric arc furnace levels (0.01% N) was found to cause a serious deterioration in ductility. V-N steel gave better ductility than Nb-containing steels due to less precipitation. From a cracking perspective, low- N steels are generally recommended but, when not feasible, a combination of Nb and V gives even better ductility. However, to be sure of avoiding transverse cracking in higher N steels a small addition of Ti is required. This resulted in a decrease in the fraction of fine particles and in accord with this better ductility. Transverse cracking of industrial slabs was then avoided.

Jan 1, 2011

Notices THE FEDERATION OF SOCIETIES OF PROFESSIONAL ENGINEERS It is expected that the National Institute of Personnel Research will be conducting a project, at the request of the Federation, to establish the relationship, if any, between the academic and professional achievements of engineers. co-operate with the researchers. INFACON 74 The National Institute for Metallurgy, the South African Institute of Mining and Metallurgy, and the Ferro Alloy Producers' Association of South Africa will hold an International Ferro-alloys Congress in Johannesburg from 22nd to 26th April, 1974. INTERNATIONAL PLATINUM SYMPOSIUM OF THE SOCIETY OF ECONOMIC GEOLOGISTS The above symposium is to be held at the U.S. Geological Survey, Denver Federal Center, Denver, Colorado, from 13th to 17th October, 1975. Papers up to 40 doublespaced THIRD MEETING-CANADIAN HYDROMETALLURGYGROUP The Hydrometallurgy Group of the Metallurgical Society, Canadian Institute of Mining and Metallurgy, will hold its Third Annual Meeting, October 1 and 2, 1973, at Edmonton Alberta. COLLOQUIUM ON THE CONSTRUCTION OF SLIMES DAMS The Institute has arranged a two day colloquium on the above topic, to be held on November 14th and 15th, 1973, at Kelvin House. The following Programme has been arranged:

By A. C. Legg

BCL Limited operates a nickel-copper flash smelting operation at Selebi-Phikwe, situated in north-eastern Botswana. The original furnace was commissioned in 1973 and produces a high grade sulphide matte, from its own concentrates plus additional custom feeds, which is shipped to refineries in Zimbabwe and Norway for further processing. In 2004 the company embarked on a study to modernize the flash smelting complex, with an emphasis on extending campaign life, improving the furnace integrity and enhancing throughput and process efficiency. First phase initiatives from this exercise, including the fundamental switch to a single concentrate burner operation of the flash smelting furnace, were implemented in July 2007. This paper summarizes experiences prior to implementation, details the specific improvements made to the flash smelting furnace and associated operations, highlights the improved plant performance after modernization, and outlines second phase expansion plans that are currently under consideration.

Jan 1, 2009

By M. E. E. Douglas, A. K. Haines, D. I. Nicol, C. M. Olëm, W. M. Craig, G. D. Louw

A description is given of the design of the continuous ion-exchange demonstration plant at Blyvooruitzicht Gold Mine, including details of the process design, the column construction, and the control system. The operating and process results gathered over a period of seventeen months are summarized, and development work and modifications to the process are discussed. It is concluded that the system comprising continuous loading and continuous elution is technically feasible and can be scaled up with confidence.

Jan 1, 1978