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Proceedings of a General Meeting held at the Witbank Golf Club at 19h30 on 3rd November, 1977 Geomechanics colloquy The 27th Geomechanics Colloquy is to be held on 12th and 13th October, 1978, in the Salzburg Congress Hall. The themes of the four half-day sessions will be as follows: Conference on pneumoconiosis The Vth International Conference on Pneumoconiosis is to be held in Caracas (Venezuela) from 29th October to 3rd November, 1978.

Jan 1, 1978

By D. A. Fenton

The structural design of large grinding mills, with reference to shell-mounted bearings by D. A. FENTON*, P. Eng. (Visitor) The paper outlines the advantages of shell-mounted grinding mills over mills having a conventional trunnionsupported shell. The growing use of larger mills in the past decade has led to a significant number of mechanical and structural failures, the most common being those at the junction of the head and the shell. Larger mill diameters favour the use of shell-mounted bearings. The elimination of castings, which have an inherent weakness to fracture, makes the shell-supported mill lighter and stronger than a conventional mill of the same shell thickness.

Jan 9, 1976

NIM reports Report no. 1845 The composition and mode of occurrence of gold in Witwatersrand ores and leach residues", Report no. 1861 The determination of some impurities in zirconium metal by instrumental neutronactivation analysis. Report no. 12 Exploratory tests on the concentration of tin ore from Kuils River, C.P. (29th Apr., 1966; re-issued Aug. 1976). Report no. 286 A mineralogical and petrographic study of the pre- Transvaal rocks in Borehole K.l, Koster district, western Transvaal. (15th Feb., 1966; re-issued Jun. 1976). Report no. 938 Life test on IRA 400 resin during the recovery of zinc chloride. (27th Mar., 1970; reissued Aug. 1976). Report no. 1010 The leaching, with hydrofluoric acid, of materials containing tantalum and niobium. (8th Jul., 1970; reissued Aug. 1976).

Jan 12, 1976

By V. H. R. Brereton

The gold deposits of the farms Lisbon and Berlyn in the Eastern Transvaal by V. C. H. R. BRERETON* (Visitor) This paper describes the discovery and recovery of gold, over a period dating back to the 1870s. on the farms Lisbon and Berlyn, situated approxim ately 1I km north-east of Pilgrims Rest. where mining ceased in July 1971. 99 years after gold was first discovered in the Pilgrims Rest and Sabie districts. Included in the paper are accounts of the discovery and mining operations of the Lisbon-Berlyn Company from 1884 to 1890. The operations of small companies and syndicates. the superficial winning of gold by diggers, and the encouraging reports of four mining engineers in 1890 are also mentioned.

Jan 11, 1973

By H. E. Cross

Metallurgical considerations in the automation of gold-recovery plants By H. E. CROSS. Pr. Eng., B.Sc. (Eng.) Hons. (Fellow) The advantages of the automation of gold-recovery plants are examined. The various sections of a gold-recovery plant are analysed, and the extent to which instrumentation can usefully be employed is described. INTRODUCTION The scope of this paper is restricted to the ore-treatment and recovery plants on Witwatersrand gold mines. To extend the field to plants that process base metals and industrial minerals would result in a paper that would be too lengthy. However, the subject matter of this paper is applicable to most mineraldressing and recovery plants and will, it is hoped, be a foundation on which to build somewhat more sophisticated control systems required in the base-metals field.

By A. Miller, M. Bétournay

The main objectives of the Mine Mechanisation and Automation program (MMAP) are to enhance health and safety in underground mining operations, facilitate mechanization and automation in narrow- vein and deep mines, provide sound science to regulatory agencies and improve mine profitability. The program, which has a unique underground and surface industrial scale facility, is involved in many multi-partner projects, like hydrogen fuel cell applications, electrification and hydraulification of underground mines, reduction of noise and vibration, miner location device, explosive-free blasting and hoisting. The paper presents an overview of the Mine Mechanisation and Automation Program of Natural Resources Canada and some of the main projects.

Sep 1, 2001

By P. H. S. W. Kulatilake

The paper introduces a computer simulation technique to estimate the target detection probabilities associated with search surveys. The technique takes into account the inherent randomness associated with the distributional properties of geologic targets. Use of the technique is illustrated through examples. The paper provides information as to how this technique can be used in obtaining the optimum sampling pattern and optimum spacing associated with target detection surveys.

Jan 1, 1987

By M. W. Hildyard, J. A. L. Napier

The improved design of support systems and stoping strategies when changes in depth, stratigraphy, or mine layouts are considered must rely on the designer's fundamental understanding of the deformation mechanisms adjacent to underground openings so that he can extrapolate and predict expected mining conditions. This paper presents a numerical approach to the modeling of the growth and interaction of mining-induced fractures near the edges of deep tabular excavations in brittle rock. Fractures are represented by displacement-discontinuity elements that are allowed to propagate according to prescribed growth rules. This procedure is justified by the reproduction of several features observed in laboratory simulations of fracturing around openings in blocks of rock subjected to uniaxial and biaxial compression. An attempt is then made to explain some of the attributes of the fracture zone surrounding tabular stopes. Particular questions of interest are the sequence in which fractures form and are mobilized in front of the mining face, the effect of parting planes parallel to the plane of the excavation, and the distribution of stress parallel to the hangingwall and footwall.

Jan 1, 1992

By R. Van Rijswick

Crankshaft driven piston and piston diaphragm pumps inherently generate a varying flow each crankshaft revolution. Depending on the system connected, this flow variation results in a pressure pulsation. This pressure pulsation may, depending on the structural design, result in structural vibrations. In order to limit the level of pressure pulsations, volume absorbing devices, mostly gas filled vessels, are used. The standard selection of these so-called dampeners is based on the flow variation of the pump but does not incorporate the interaction with the connected system. The paper discusses the application of a pulsation analysis tool developed by WEIR Minerals Netherlands, manufacturer of GEHO positive displacement slurry pumps. The paper first discusses the basics of pressure pulsation analysis, such as flow variation generated by crankshaft driven pumps, and hydraulic effects such as capacitance, inductance and resistance and their influence on the hydraulic response of a system. Furthermore, the relation between pressure pulsations and structural vibrations, known as fluid structure interaction, will be discussed. Additionally, the capabilities of the pump pulsation analysis tool are presented, illustrated by examples of simulation results and experimental verification.

Jan 1, 2007

By P. J. F. Fourie

The purpose and frequency of comprehensive performance testing and the types of tests to be included are discussed. The results obtained from a series of such tests are reviewed.

Jan 1, 1980

By C. Fiore, A. Kok, W. C. Coningsby

Quarrying is a comparatively simple process which is open to certain economic pitfalls, One of these is the appropriate size of the equipment needed to meet demand.

Jul 1, 1970

NIM Reports Report No. 1647 The industrial application of KEGOLD electrodes. Report No. 1665 The determination of minor amounts of antimony in ores and concentrates by atomic absorption spectrophotometry.

Jan 1, 1975

Letter to the Editor With reference to the recent questionnaire in the December 1980 issue on 'The Contents of Journals', I have made the following observations.

Jan 1, 1981

By P. G. Mason, H. T. Brown

Electrowinning of nickel at the Bindura Smelting and Refining Company by H. T. BROWN, B.Sc. (Member) and P. G. MASON, B.Sc. (Member) After a brief discussion of theoretical considerations in the electrowinning of nickel, an account is given of the electrowinning process and plant used at the Bindura Smelting and Refining Company.

Jan 2, 1977

The second annual student prize giving function of the South African Institute of Mining and Metallurgy was held in the Van der Byl Hall, University of Pretoria, on Thursday, 10th March, 1978. The main address (see opposite page) was given by Dr T. F. Muller, Chairman of Iscor.

Jan 1, 1978

By G. P. L. van der Linde

EVERY OREBODY IS UNIQUE [ ] GEOLOGY AND MINERALIZATION DIFFERENT [ ]

Jan 1, 2005

By G. Paul

The mechanism of nodular crystallisation of graphite in the production of spheroidal cast Iron is not fully understood. The work reported In this paper confirms that in cast iron melts having a high Interfacial tension against the environmental atmosphere, the graphite tends to crystallise in nodules during solidification. The Influence of Interfacial tension between melt and solid graphite is similar.

By C. M. Sellars, W. E. Stumpf

SYNOPSIS The effects of concurrent recovery, prior creep deformation and concurrent high temperature fatigue on the coarsening of some carbides in steels have been studied. It was found that concurrent recovery enhances the coarsening rate by orders of magnitude and prior creep deformation causes an enhancement of about two times. Finally, concurrent fatigue causes an initial greatly enhanced coarsening rate but after prolonged cycling dissolution of the carbides occurs.

The 87th Annual General Meeting of the South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on Wednesday, 15th August, 1984. Professor R.P. King (President) was in the chair, and declared the meeting open at 16h00.

Jan 1, 1984

By C. A. Hunt

The problem of materials balancing is reviewed with particular reference to the minerals industry. A broad statistical framework is established that, besides extending the classical estimation problem, allows questions concerning the value of sample information to be addressed. The following are examples of such questions: How much money should be spent on sampling? Which streams in a plant should be sampled? What should be sampled? The approach adopted makes use of Bayesian analysis. The discussion includes an illustrative example involving a simple flotation circuit.

Jan 1, 1985