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By M. R. Bitarafan

Mining method selection is the first and most important problem in mine design. In this selection some of the parameters such as geological and geotechnical properties, economic parameters and geographical factors are involved. The mining engineer must balance the input parameters and select the method that appears to be the most suitable; mining method selection is both an art and a science. Distinguishing all parameters that have an effect in mining method selection and in the determination of weighting factors of any parameter is a difficult task in an ordinary environment. This paper attempts to determine important parameters that impact on the mining method selection and demonstrates the calculation of the weighting factors for each selected parameter. This study has been directed to the research of a methodology for the selection of an optimal mining method. Different fuzzy methods are presented as an innovative tool for criteria aggregation in mining decision problems. Two methods of fuzzy multiple criteria decision making are used for selecting the optimal method with which to mine anomaly No. 3 of the Gol-Gohar iron mine. This paper finally presents a comparison of the selection methodologies and further discusses the most appropriate method investigated.

Jan 1, 2004

By J. F. Shao, G. Duveau, W. Z. Chen, O. Ozanam

In this paper, we present a sensitivity study for the numerical modelling of hydromechanical coupling around a shaft in partially saturated claystone. Two representative constitutive models have been used: an elastoplastic damage model (IDEPLML) and an elastic perfect plastic model based on the Hoek and Brown failure criterion (H&B). A series of comparative studies have been performed with respect to main parameters involved in coupling process (mechanical, hydraulic and hydric properties). The emphasis is put on the evaluation of induced plastic, damaged and failed zone due to excavation and drying process. Dans ce papier, nous présentons une étude numérique paramétrique du comportement hydromécanique couplé d’une argilite partiellement saturé, lors du creusement et de la maintenance d’un puit L’étude paramétrique porte à la fois sur le type de modèle et sur les principaux paramètres (mécaniques hydrauliques et hydriques) intervenant dans le couplage. L’accent est principalement porté sur l’évaluation des zones plastifiées autour de l’ouvrage lors de la désaturation. In unserem Beitrag geht es um eine digitale parametrische Untersuchung über das hydromechanische Verhalten eines teilweise durchtränkten Tons beim Abteufen und dem Betrieb von Schächten. Die parametrische Analyse konzentriert sich auf den Modelltypus und auf die wesentlichen bei der Verbindung wirksamen Parameter, d.h. die mechanischen, hydraulischen und hydrologischen. Der Schwerpunkt liegt auf der Bewährung der plastifizierten Bereiche des Bauwerkes während der Austrocknung.

Jan 1, 2003

By R. Armstrong, C. Ware, P. Sudan, G. Whitmore

The northern KwaZulu-Natal (KZN) coastal dune cordon, South Africa, extends from north of Durban into Mozambique. The Quaternary dune cordon, which can be up to 2 km wide, comprises a series of stacked, unconsolidated dunes that in places attain a height of over 100 m. Mining of the dunes produces much of the world’s supply of ilmenite, rutile and zircon. This paper documents the age of zircon grains separated from dune units, identifies likely source rocks and presents an evolutionary history for the dune cordon. Between 30 and 60 detrital zircon grains from three distinct units from the northern KZN coastal dunes were analysed for U/Pb isotopic ages using the SHRIMP II at the Australian National University. The samples represent units from the base (ca. 250 ka; luminescence age1),middle (ca. 190 ka2) and upper (ca. 20 ka2) portions of the coastal dune cordon. Zircon grain ages identify three source populations: (1) a 1 000 to 1 200 Ma group correlated to the Natal Metamorphic Province, (2) a 500 to 650 Ma group representing a Pan-African belt, which may correlate to the Mozambique Belt and (3) a ca. 650 to 800 Ma group of unknown provenance. Surprisingly, the presently exposed basement, comprising the Kaapvaal Craton and Archaean volcano-sedimentary sequences, has not supplied a significant amount of zircon grains (< 5%).This suggests that unroofing of basement rocks in the region has only occurred during the last 20ka. In addition, the absence of zircon grains younger than 500 Ma indicates that the bulk of zirconis not reworked from the Karoo Supergroup cover succession, but may be sourced by reworking of the Natal Group sandstones.

Jan 1, 2003

By R. J. Forzatti

The production of sulphuric acid from sulphur generates heat. The majority of this heat is recovered as steam and is often used to generate electricity. Heat not recovered as steam is rejected to cooling water systems. The design of the turbine, condenser, and cooling water systems impacts the overall water, energy, and environmental footprint of the plant. This review considers a conceptual 2000 t/d sulphuric acid plant with several alternative cooling water systems. The review utilizes Hatch?s 4 Quadrant sustainable design tool to compare the alternatives on both an economic and a weighted sustainability scale.

Jan 1, 2014

By F. S. A. de Frey

The author would like to refer to his contribution to the paper `Design of pillar systems in South Africa&apos; by Ozbay et al. 1. The authors agreed `wholeheartedly that further research, together with carefully planned field trials, in pursuit of this potentially highly rewarding concept&apos; of the small span small pillar method is warranted. On 30 September 2010 the author went underground at the Kroondal Chrome Mine to observe how the concept of smaller spans was being applied. He was pleasantly surprised to find that the typical coal mine bord and pillar sytem was being used very successfully. Although the deepest mining was taking place at a depth of only 450 metres, Kroondal would be an ideal mine to do further research together with carefully planned field trials. At Crown Mines Gold Mine, where the author worked, he was informed that the first recorded rockburst took place at a depth of 635 metres below surface. The depth of the platinum and chrome mines is increasing, with the risk of an excalation in injuries and fatalities due to &apos;backbreaks&apos; and siesmic activity. The rock engineer at Kroondal was not aware of backbreaks occuring on the mine. It is important that the rock engineers of the base mineral and gold mines get together and give more serious attention to the host rock environment in which the pillars are situated.

Jan 1, 2011

By Christian Heili

In 1991 the Government of the Republic of Zambia passed legislation providing for the privatisation of Zambia Consolidated Copper Mines Limited (ZCCM). The newly formed Mining Companies, established after nearly a decade of difficult and protracted negotiations on such matters as, cash at close; retained percentage interest by ZCCM; equity investment; future investment commitment and tax concessions, were faced with great internal challenges and a harsh external environment. There was a convergence of a number of negative forces that had and will continue to have an impact on the mining environment in Zambia. The most crucial of these being, the competitive pressures of the global economy, fluctuating copper price and the prevailing HIV/AIDS pandemic. In the short period after privatisation, the Industry has seen the collapse of Binani Industries (Luanshya Mine), the withdrawal of Anglo America Corporation from Konkola Copper Mines Plc and the disposal of Chambishi Cobalt and Acid Plants by Anglovaal Mining Ltd. The objective of this paper is to provide a theoretical and practically researched foundation, which may be used to assist Zambian Mining Companies in making informed decisions on the issue of Strategic Outsourcing and the degree to which this may support the successful and sustainable growth of the Zambian Copper Mining Industry. If judiciously implemented, Strategic Outsourcing has the potential to generate a practical business valuation and process to assist Mine Management in the achievement of their business goals and consequently the return on investment to their Shareholders.

Jan 1, 2005

By M. I. Brittan

SYNOPSIS The key reactions of the copper segregation process have been studied with a view to establishing the kinetics of the system. The investigation was carried out using two refractory copper ores from the Zambian Copperbelt in a small-scale, fluidized bed, chloridization reactor. The rate of chloridization of the copper in the ores is compared with the rate of volatilization of the cuprous chloride produced and with the rate of reduction of the cuprous chloride to form segregated metallic copper. In conjunction with available data on the rate of production of hydrogen chloride in a segregation system and with due regard to the conditions applicable in a TORCO reactor, it is concluded that the chloridization reaction is the major rate limiting step of the process. Factors influencing the rate of this extraction step and aspects of its mechanism are examined. The findings have confirmed the validity of the existing theory of segregation and provide insight as to the viability of the system of reactions involved in the copper segregation phenomenon. Experimental results which relate to observations made in the course of TORCO plant operation and segregation studies are discussed.

By H. A. D. Kirsten

SYNOPSIS This paper describes simple calculations to evaluate the stability of hangingwall and footwall strata at the work¬ing face and in backfilled areas. It shows that the benefits of support provided by backfill can best be realized when the fill is placed as close to the face as possible. The main beneficial effects of fill are that it reduces the stope span, at the same time providing a damping effect on vibrations, and prevents the fall-out of blocks in filled areas, thus maintaining the competence of the strata.

Jan 1, 1988

By G. Chunnett

Platinum metal prices have risen significantly during the past 18 months, and have remained at elevated levels. Driving these bullish prices are sustained jewellery demand, mainly from the Far Eastern markets, and ongoing autocatalyst usage in response to ever more demanding global environmental legislative requirements. Within South Africa, the areas north and south of the Steelpoort River in the Eastern Bushveldare well known for their significant resources of platinum. The bulk of the resources have lain dormant in anticipation of the very situation that is currently occurring in the marketplace. Anglo Platinum is the largest primary platinum producer in the country, and is uniquely positioned to take advantage of the current elevated metal prices and shortfall in supply of platiniferous metals. In addition to its production capabilities, Anglo Platinum holds an extensive portfolio of mineral reserves and resources which underpin its ability to implement expansion projects to continue growth in platinum group metal production. It also has access to, and is actively expediting, the exploration of a range of properties where the company can further expand current production capacity or supplemented depleted production levels.

Jan 1, 2006

By M. Jeffrey

This study investigated the elution of precious and toxic metals from activated carbon. Gold and mercury are of primary interest, due to their value and environmental impact respectively. A laboratory elution rig was commissioned to simulate industrial Zadra and AARL carbon elution conditions. Mercury was found to elute most effectively in strong caustic cyanide solutions; gold was found to elute most effectively in hot low ionic strength solutions. As cyanide decomposes on contact with activated carbon at high temperatures, optimum elution conditions for gold conflicts with those for mercury?no practical compromise in conditions was found. However, sequential elution allowed reasonable recovery of both metals. Ongoing work is looking at the deportment of other metals under elution conditions.

Jan 1, 2009

By S. Vorberg, J. Preussner, B. Fischer, U. Glatzel, R. Völkl, M. Wenderoth

Pt-Al-X alloys have shown good mechanical properties and adequate oxidation resistance. Starting from a promising Pt-Al-Cr alloy, the influence of Ni additions was investigated. After ageing finely dispersed precipitates are observed. Nb, Ta, Ti and Re increase strength when added as partial substitute for Al. Minor additions of B increase creep resistance and rupture time remarkably, owing to strengthening of the grain boundaries. The evolution of the alloy development programme as well as selected properties of the multi-component Pt-base alloys are presented.

Jan 1, 2006

By J. de Villiers

Through the application of the Rietveld method, X-ray diffraction analysis has developed into a fully quantitative method for phase analysis. The Rietveld method itself has progressed from an unstable method that required constant operator intervention to a stable and robust method suited even for routine analysis. The method, however, requires a good initial calibration and periodic checks on its precision and accuracy. Several examples from minerals processing, pyrometallurgy, and materials science show the strengths and applicability of the method. The limitations and sources of error are also discussed.

Jan 1, 2007

By C. Atilla Öztürk

Determining the cutability and mechanical properties of rocks is vital for the feasibility studies of a mine or tunnel projects. Many scientists have investigated the correlation between these parameters in order to predict specific energy (SE) and other important rock cutability properties for many years. On the other hand, textural properties of rocks have been quantified in detail by Howarth and Rowlands (1987). Hence, it was possible to correlate mechanical and textural properties of rocks by using a parameter known as the texture coefficient (TC). The main objective of this study was to use the test results taken from a research project carried out by Bilgin and Shahrair1tocorrelate the mechanical and cutability properties of rocks with textural properties of rocks. For this purpose, uniaxial compressive strength (UCS), uniaxial tensile strength (UTS), cone indent or (CI),point load index (PLI), unit volume weight (?), porosity, SE, and normal and cutting force values, were correlated with textural properties of rocks. Hence it was possible to make illuminating interpretations about the relationships between the mechanical and cutability with the textural properties of rocks. Keywords: Cutting properties, mechanical properties, specific energy, texture coefficient.

Jan 1, 2004

Your Council has pleasure in submitting its report for the year ended 30th June, 1970. COUNCIL The following served as Office Bearers during the year under review: Messrs J. K. E. Douglas (President), V. C. Robinson and Prof D. D. Howat (Vice-Presidents), R. C. J. Goode (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Members of Council: Mr. R. J. Adamson, Dr. M. G. Atmore, Mr M. Barcza, Dr J. M. Bereza, Messrs H. Britten, H. E. Cross, A. R. C. Fowler, G. W. Holl, Dr J. P. Hugo, Messrs N. A. Honnet, P. Lambooy, Prof J. de V. Lambrechts, Mr C. E. Mavrocordatos, Dr J. T. McIntyre, Messrs J. Meintjies, T. C. A. Meyer, J. A. Nixon, Prof R. P. Plewman, Dr R. E. Robinson, Messrs J. F. Reid, H. Simon and P. W. J. van Rensburg. Ten Council meetings were held during the year with an average attendance of seventeen and the standing committees held 45 meetings. FINANCE The annual accounts, which are attached to this report, show an excess of expenditure over income of R4,608 compared with R2,124 last year. This deterioration can be attributed largely to two important factors, namely an increase in secretarial fees of RI, 789 and an increase in the loss on the Journal from R2,343 to R3,508. In addition, our contribution to the expenses of the Federation of Societies of Professional Engineers increased by R607 from R549 to R1,156. The increase in secretarial fees is partly due to our increased demand for services and partly to increased salaries. In order to maintain its essential services it has been necessary for the A.S. & T.S. to increase salaries in order to keep pace with commerce and industry. With regard to the Journal, we did not expect immediate dramatic results from the changes that were effected as from the beginning of last year in the arrangements for publication. However, the improvement has been even slower in materialising than we expected. This situation is being watched carefully and we will not hesitate to make further changes if necessary. It became clear early in the year that the financial position was deteriorating and your Council decided that it was essential to meet the situation by raising subscriptions and entrance fees. At the same time it was decided that there are no grounds for a distinction between Town and Country members and that in future the scale for the compounding of subscriptions should be based on anticipated future membership, rather than past membership. These changes have had only a minor effect on the accounts under consideration. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of R132 and the total fund was, therefore, increased by this amount to R4,338. The balance sheet shows that the market value of quoted shares and debentures decreased during the year from R13,059 to R6,567, while accumulated funds now amount to R17,959 compared with R22,567 last year. It will also be noted that we are holding R25,844 on behalf of the Symposium on Opencast Mining. MEMBERSHIP Twenty-eight Fellows, twenty-four Members, seventeen Graduates, twenty-five Associates and twenty-seven Students were elected during the year. Four Members were admitted to Life Membership; Five Members were transferred to the grade of Fellow; one Student was transferred to the grade of Member; two Graduates and one Student were transferred to the grade of Member; six Students were transferred to the grade of Graduate; One Associate was transferred to the grade of Fellow; One Associate was transferred to the grade of Graduate. One Fellow, one Member, six Graduates, four Affiliates and ten Students were removed from the Membership Roll in terms of by-law 7.7.1. Your Council records with deep regret the death during the year, of the following: R. A. H. Flugge-de-Smidt, C. S. McLean, Dr H. J. van Eck, (Honorary Life Fellows), J. C. Humphreys, O. Lazar (Life Fellows), D. G. Beadle, J. G. Craig, P. U. Fisher, R. G. McConnell, J. H. Moore, S. Sterling, L. R. Ulyate (Fellows), H. H. Burger, E. A C. Dickson, R. Jack, S. Ring (Members), M. J. Worrall (Graduate). A comparative statement of the membership as at 30th June, 1970, and the end of the previous year is shown in the following tabulation: 30th June 30th June Honorary Life Fellows 10 8 Honorary Fellows 6 6 Life Fellows 189 191 Fellows 514 530 Members 448 465 Graduates 68 80 Associates 155 172 Students 162 161 1,552 1,613 RECLASSIFICATION OF MEMBERSHIP The designations of grades of membership were altered to accord with the practice in professional institutes both here and overseas and members were advised of the new classifications. MEMBERSHIP DRIVE A committee was established to organise a drive for membership as it was felt that there are numbers of persons in our mining and metallurgical industries who are not yet members but who qualify for membership. Members of the committee were allocated responsibility for campaigning in sections of industry and for publicising the aims, objectives and advantages of belonging to the Institute.

By J. N. van de Merwe

CONTRIBUTION BYH. WAGNER AND T.T. OZAN The paper by Dr J.N. van der Merwe makes an important contribution to the design of bord-and-pillar workings in the Vaal basin. It has been recognised for some time that the strength of coal seams in the Vaal basin is markedly lower than that of coal seams in other coal-mining districts in South Africa. However, there was insufficient data to quantify how much weaker the extensively jointed coal the Vaal basin is. A number of recent pillar collapses that occurred at Sigma colliery, the only remaining underground colliery in the Vaal basin, provided Dr Van der Merwe with an opportunity to make this assessment.

Jan 1, 1993

By P. R. Jochens, D. D. Howat, M. S. Rennie

The slags arising from ferrochromium plants were simulated by additions of CaO and Fe2O3 (6 per cent each), Cr2O3 (7 and 12 per cent), and Fe2O3 and Cr2O3 together (6 and 12 per cent respectively) to slags in the MgO-Al2O3-SiO2 system. These additions were made to slags having an SiO2 content of 45 per cent and an MgO-to-Al2O3 ratio of 4 to 3 or 3 to 4. The effect of these oxide additions on the liquidus temperatures, electrical conductivities, and viscosities was determined. The additions of CaO and Fe2O3, although having little effect on liquidus temperatures, decreased viscosity and increased electrical conductivity. The addition of Cr2O3 raised the liquidus temperatures considerably, and tended to decrease viscosity in the temperature range 1 700 to 1 800°C and to increase electrical conductivity.

By J. Arzuúa, U. Castro-Filgueira, L. R. Alejano, F. Malan

"Pillar design for underground mining is typically done using empirical formulae or numerical modelling. Practical experience and recent literature, nevertheless, illustrate the shortcomings of these design approaches. Ongoing monitoring of pillars is therefore recommended to minimize the risk associated with these designs.In a mine where a large number of pillars are cut, different pillar strengths can be expected owing to variations in rock mass strength from area to area. This problem is compounded by the fact that in mining environments the pillars are not always cut according to the prescribed dimensions. Although the original design using either empirical methods or modelling may predict stable pillars, unstable pillars will be encountered in reality. Very conservative designs with large factors of safety may circumvent this problem, but this approach is uneconomical.A possible solution to localized stability problems may be to enhance the strength of a few unstable pillars. It may even be hypothesized that reinforcing a few critical pillars may prevent ‘pillar runs’ on a much larger scale. Rockbolting, strapping of pillars, and pillar shotcreting have occasionally been used in the past as possible solutions. It appears that these have not been successful in all cases and large collapses have occurred in spite of the pillar remedial work.The authors investigated the strapping of pillars by conducting laboratory tests on cabled rock specimens. The results were qualitatively compared to actual attempts of pillar reinforcement available in the literature, as well as additional observations in an old haematite roomand- pillar mine in Spain. Based on these results, the value of steel cabling and mesh wrapped around pillars to improve stability is demonstrated. Some cases where this approach will not be successful are also discussed."

Jan 1, 2017

By A Weber, L MacNamara, H Schreiber

Design and development of the world?s largest flotation cell was completed in 2002. This was the first 257 m3 flotation cell installed in the mineral industry and represents a major development in the design of larger flotation cells. This cell has a 50% increase in volume over the widely installed 160 m3 WEMCO® Smartcell? flotation machine. In the next few years it is anticipated that 257 m3 flotation cells will be incorporated into rougher-scavenger flotation circuits in many more world class copper sulphide concentrators. The prototype 257 m3 cell, No.250 Smartcell? flotation machine was installed at Minera Los Pelambres in the front of Row 1 in the existing rougher flotation circuit. This cell is followed by nine No. 130 Smartcell? flotation cells. After the successful development phase, this unit has been incorporated as part of a row of No. 250 Smartcell? flotation machines at Minera Los Pelambres. A key to the successful development of the equipment has been the emphasis placed on fundamental hydrodynamic scale-up criteria. Hydrodynamic factors include superficial gas velocity, water (pulp) circulation through the draft tube, and pulp mixing (distribution) characteristics. This paper will review the scale-up criteria of the No. 250 flotation cell, and present a case study of the in-plant equipment testing. The case study will document the metallurgical and hydrodynamic performance of the machine. It will also illustrate the economic benefits derived by incorporating larger flotation cells in a modern copper sulphide concentrator.

Jan 1, 2007

Today&apos;s conservation thinking is becoming increasingly polarised-a widening gap that could eventually be to the overall detriment of mankind, one way or the other. In one corner, stand the disciples of the untainted wilderness, moral protectors of the natural world who subscribe to the doctrine that the fragile balance of nature is threatened by man&apos;s very existence. On the opposite side of the ring, stands the relentless developer, with the megalomaniac notion that nature is purely there to serve humanity and civilisation, under the auspices of &apos;progress&apos;,

Jan 1, 1996

By R. Layton

Expert Systems Technology (EST) is becoming more and more widespread in both its range of applications and the public interest. It appears to be capable of performing tasks unmatched by other techniques. Within the mining industry a large body of unsolved problems now appear to have a solution. This paper examines the current state of EST both in the context of the history of Artificial Intelligence and current efforts at building mining expert systems. It provides recommendations for those wishing to get involved, and outlines the problems for those who believe that expert systems are capable of anything and everything. The paper also provides a detailed analysis of limitations of current EST that must direct research into more fundamental, commonsense areas than have been extensively covered before.

Jan 1, 1987