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By J. E. Furze

World-wide hikes in the oil price and the prospect of future scar cities of liquid and gaseous fuels have given enhanced status to the South African coal industry. It is thus understandable that the colloquium held at Wit bank on 3rd and 4th October, 1979, and organized jointly by the South African Institute of Mining and Metallurgy and the South African Coal Processing Society should have attracted more than 400 delegates.

Jan 1, 1979

By S. Erçayhan, B. Derin, O. Yücel

In the present study, the production of low carbon ferrochromium (LC-FeCr) from chromite concentrates containing 55.09% Cr2O3 and 13.06% Fe via metallothermic process was investigated. For this aim, in the experiments, the aluminothermic reduction method was applied in an open crucible. 10% CrO3 + 10% NaClO3, 15% CrO3 + 5% NaClO3 and 20% CrO3 by weight of concentrate were added to the charge, respectively and the charge was reduced with aluminium. The experiments were done with the additions of 90, 100, 110, 120 and 130% of stoichiometric requirement of aluminium. The highest Cr content in alloys was found as 71.7% at 120% of stoichiometric Al whereas the highest Cr recovery in alloys was found as 71.8% at 130% of stoichiometric Al when the both charge contained 15% CrO3 + 5% NaClO3 by weight of chromite concentrate.

Jan 1, 2004

Notices TRANSPORTATION AND THE ENVIRO NMENT The 5th Quinquennial Convention of the S.A. Institution of Civil Engineers will take place at the Carlton Centre, Johannesburg, from 20th to 24th August, 1973. ENVIRONMENTAL ENGINEERING A conference on environmental engineering problems in industrialized and developing countries is to be held at the United Engineering Centre, New York, on 19th and 20th September, 1973. RABCEWICZ-COLLOQUY The Austrian Society for Geomechanics is to honour Professor Ladislaus V. Rabcewicz, on the occasion of his 80th birthday, with a meeting in Salzburg Congress Hall on 11th and 12th October, 1973. The themes of the four half-day sessions will be as follows. PYRO MET ALL URG ICAL EVENTS IN 1974 Diisseldorf is to be the venue for the following three events: International Iron and Steel Congress O.F.S. Branch Welkom THE MARCH GENERAL MEETING OF THE BRANCH WAS HELD IN THE ST. HELENA CLUB AT 8.00 P.M. ON TUESDAY, 6TH MARCH, 1973 O.F.S. Branch Welkom MINUTES OF A GENERAL MEETING HELD IN THE ST. HELENA CLUB ON WEDNESDAY, 16TH MAY, 1973, AT 8.00 P.M.

By D. D. Marsden

The paper briefly outlines the history of the successful development of vegetating techniques for mine-residue deposits. It seeks to place on record the major roles played by M.J. Mrost, who initiated and systematically developed the concept, and W.H. Cook, who continued the trials and successfully directed a stupendous large-scale project. The vegetating techniques currently practised are outlined, and it is concluded that vegetating is still the only surface-stabilizing technique of any significance that is employed throughout the world.

Jan 1, 1987

By G. Matheron

This paper discusses important aspects, both psychological and methodological, which have delayed the introduction of geostatistics in practice. The evolution of geostatistics is traced through three 'generations', and in conclusion some important questions are raised on the current status of the subject and possible areas of future research.

Jan 1, 1987

By G. de B. van Niekerk

This paper briefly outlines some mining technology that is used with success in Australia but is not yet fully utilized in South Africa. The following aspects are discussed: improved rotary-drill bit performance, use of trucks and load haul- dump units underground, long-hole raising, blasting techniques, and the use of butterfly roofbolt plates for support.

Jan 1, 1989

By M. U. Ozbay, D. R. Lougher

An in-situ experimental programme was carried out to improve the understanding of the rockmass and pillar behaviour in moderately deep hard-rock mines. The experiments were carried out at Impala Platinum mines and consisted of precise levelling measurements in the footwall of the reef, stress measurements in pillars, convergence measurements in the stope, and petroscope observations in pillars. The results were analyzed using a computer program in an attempt to quantify the characteristic behaviour of the rockmass as well as the pillars. The measured off-reef displacement data were found to co11fonn to the trends obtained from elastic modelling and the correlation could be improved by modelling the small pillars with reduced modulus to simulate yielding' of the pillars. The stress strain curve obtained from analyzing the in situ results, showed that a 6x 3 xl m pillar yields without significant load shedding at peak stress levels of approximately 208 MPa. The closure measurements confirmed that the mechanism of yielding is mainly that of pillars punching into the foundations. Slight to moderate sidewall fracturing and slabbing might be contributing to yielding, but to a much lesser degree than the former mechanism, as the petroscope observation revealed the existence of an intact region beyond 0,6m from the pillar sides.

Jan 1, 1995

By B. M. Van Vliet

SYNOPSIS This paper outlines the principles involved in the regeneration of activated carbon for renewed use in the recovery of precious metals or the purification of water. While chemical methods are effective in restoring the activity of spent activated carbon containing only single or defined adsorbates, thermal methods have to be used when the spent carbon is loaded with a heterogeneous mixture of adsorbates such as those normally present in industrial process streams or effluents. The steps involved in thermal regeneration are described, together with the operating conditions that can be controlled to give the required degree of activation. Finally, an account is given of the structural changes that occur in a new or spent activated carbon during thermal treatment.

Jan 1, 1991

By M. Suzuki, T. Shiomi, M. Nakada, K. Tsutsumi

Mold powder plays an important role in the continuous casting process for high quality steel production. It is well known that mold powder entrapment causes surface defects in steel sheet and the high viscosity of mold powder prevents the entrapment of mold powder in molten steel in ultra low carbon steel. This paper deals with the entrapment of mold powder caused by suction by Karman?s vortex in a laboratory experiment. At first the effect of the viscosity of oil and interfacial tension between water and oil was investigated in a water model experiment. Then hot model experiments were carried out by mold powder and molten steel. The amount of mold powder entrapment was affected by the viscosity and the interfacial tension between molten steel and mold powder. As a result, the following equation of the mold powder entrapment was obtained. m=1.06*107?-0.255?m-s-2.18 The amount of mold powder entrapment decreased when the viscosity and interfacial tension increased. But the effect of viscosity was larger than that of interfacial tension in the case of the industrial mold powder when the viscosity was under 0.5 Pa.s, interfacial tension was from 1200to 1300 mN/m.

Jan 1, 2004

NIM reports Report no. 1970 List of unrestricted NIM publications issued from 1966 to 1978. (30th Jun., 1978). Report no. 1976 The preparation and certification of two samples of chromium ore. (9th Sep., 1978). Report no. 1982 The resistivity of mixtures of Mamatwan manganese ore and reducing agents. (31st Aug., 1978). Report no. 1984 Commissioning of the AEI MS702 mass spectrometer. 31st Aug., 1978). Metallurgical slags The Basic Science Section of the Canadian Institute of Mining and Metallurgy is sponsoring an International Symposium on Metallurgical Slags, which is to be held in Halifax, Nova Scotia, during 24th to 28th August, 1980. Mining machinery An international conference on mining machinery is to be held in Brisbane, Australia, from 2nd to 6th July, 1979.

Jan 1, 1979

A back-propagation model, which is typical of the models used in the science of artificial neural networks, was applied to the prediction of gossans from the southeast area of Habei Province in China. A success rate of 100 per cent was achieved. The results show that the neural-network approach is good, and that it can be used effectively in the prediction of multi metallic deposits.

Jan 1, 1995

By P. A. J. Cabassi, B. K. Loveday, M. J. Wilkinson, P. H. Radcliffe

The recovery of gold, uranium, and pyrite from accumulated residues at mines in the Orange Free State is adversely affected by the presence of pyrophyllite, which is naturally floatable and must be prevented from floating with the desired constituents by the use of a mica depressant, and of thucholite (uraniferous kerogen), which contains significant quantities of uranium and gold but does not float readily in the presence of a mica depressant. In laboratory tests on these residues, the use of a mixture of MIBC (methyl isobutyl carbinol) and paraffin in addition to the suite of reagents normally used was found to increase the gold recovery substantially, but the sulphur grade was lower. The recovery of thucholite also increased considerably, but the proportion of uranium associated with this mineral was small. Plant trials, which are continuing, have been encouraging, indicating an increase in the gold recovery of 4,6 per cent.

Jan 1, 1983

By P. T. Slatter

The role of viscometers for rheological characterization in the hydraulic transport of solids is discussed, and rheological models and phenomena pertinent to the hydraulic transport of backfill material are reviewed. The two main branches of viscometry (rotational and tube) for the measurement of mining slimes rheology are compared. The effects of solids concentration, particle size and chemical additives and the practical application of rheology in backfill system design are presented.

Jan 1, 1988

By S. C. Everett, I. S. Schache, P. A. Bannister, G. F. Balderson

The Pooncarie Project is located in the Murray Basin region of Australia. This region is a potential new mineral sands province. Due to the geological environment and the lithology of the deposit, these deposits have some technical challenges that need to be addressed prior to their successful development. Within the Pooncarie Project the Ginkgo deposit will be developed first. The technical challenges it presents include its geographical isolation, the requirement to remove substantial quantities of overburden as well as the processing issues raised by the highly weathered nature of the ilmenite family of minerals. Ore characterization bench scale testwork and bulk sample pilot plant programmes have been carried out and the data obtained used to design flowsheets for both the wet plant and mineral separation plant circuits with the flexibility to enable these plants to handle the variable heavy mineral assemblage. In addition to the solving of the processing challenges, technical issues such as removal of overburden for the minimum unit cost, the use of hyper saline water in the dredge pond and the provision of infrastructure, have had to be addressed. None the less, the orebodies making up the Pooncarie Project have many positive features including low slimes content, good rutile and zircon grades and the ability to recover most of the ilmenite family of minerals into acceptable TiO2pigment feedstocks. The development of the project is set to proceed with the establishment of mining operations on the Ginkgo orebody feeding a mineral separation plant at Broken Hill. The initial shipment of products is expected to occur in early 2005.

Jan 1, 2003

One of the important facets of The South African Institute of Mining and Metallurgy is its service to its members. One way of achieving this objective is by pursuing an active branch structure. In this Spotlight, Richard Beck, Holder of the Regional Development Portfolio, gives the aims of the Institute's branches, with a short note on each branch prepared by the regional chairman. Aims of the Branches: The primary aims of the Branches of The South African Institute of Mining and Metallurgy are those of the Institute itself: to further the interest of its members, to uphold the status of the mining and metallurgical profession, and to promote the image of mining and metallurgy. Beyond these 'high' objectives, the branches have a special function in providing a more intimate relationship between the Institute and its members. The branches enable members who live outside the Johannesburg area to participate in the affairs of the Institute to an extent that would not otherwise be possible and that they themselves can define. This is achieved through the holding of social events, colloquia, and visits.

Jan 1, 1990

Copper cyanide is a common component of cyanide-treatable precious metal ores. The copper concentration in production heaps can be predicted from laboratory column tests, but the exact correlation is not necessarily intuitive. Generally, heap leach operators like to keep copper concentrations in solution below 300?500 ppm and may note problems with gold recovery and cyanide consumption when copper concentrations exceed this amount. There are several methods of copper removal from cyanide solutions including ion exchange; direct electrowinning; acidification, volatilization, and recovery (AVR); and sulphide precipitation such as the sulphidization, acidification, recycling, and thickening (SART) process. SART involves acidification with addition of soluble sulphide, separation of the resulting copper sulphide precipitate, and addition of lime to re-establish alkalinity prior to returning the solution to the leaching process, recovering both copper and cyanide as valuable products. In principle SART is very simple. Yet some SART plants that have been built may have been unnecessarily complex. This paper explores the basics of SART and makes the case for a simple plant design as applied to the heap leaching circuit.

Jan 1, 2012

By F. T. Cawood, M. A. Jooste

This paper describes the survey monitoring processes at Venetia, which are discussed under visual inspections, ad hoc investigations, system monitoring and slope stability radar monitoring. This is followed by a description of the main survey monitoring methods. The next section briefly states typical problems, i.e. the atmospheric corrections required to adjust total station distances, maintenance of the system and management of the monitoring process. The paper ends with some important lessons that could be applied to similar monitoring programmes. These lessons are firstly, communication is most important, process a vital part of the system, a champion must take responsibility for the programme and system planning ensures that the monitoring results are needs driven.

Jan 1, 2006

By F. H. Deist, R. P. Plewman

The history of development of analytical techniques for the determination of elastic behaviour around tabular excavations, is examined briefly. The design of a completely digital system, which appears to afford considerable improvements in speed, accuracy and versatility compared with existing analogue methods, is described in detail. The practical application of this system is illustrated by means of an actual underground problem. The results are presented, not in the form of specific solutions to the mine's problems, but as indications of the versatility and scope of the new method.

By B. Strohmeier

An account is given of the use of a computer to control the performance of three ultra-high-powered electric-arc furnaces in Iscor 5 steelmaking plant at Vanderbijlpark, South Africa. Several of the reports and graphs printed by the computer are reproduced.

Jan 1, 1985

By J. D. Koch

A 'project' is defined here as a process in which an idea is developed from its inception until either it is discarded or the product of the idea has been accepted by the ultimate user. The phases in a project, particularly the early phases, are examined, and project organization is described and contrasted with a functional line-management type of organization. Emphasis is placed on comprehensive definition, which is vitally important to the achievement of the goals of time, cost, and quality set for a project.

Jan 1, 1981