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By J. T. M. Amphlett, C. A. Sharrad, M. D. Ogden, R. I. Foster

"A renewed interest in nuclear power around the world in order to reduce greenhouse gas emissions is going to increase demand for uranium as fuel. This will result in more uranium being mined, which will in turn increase associated environmental pressures, such as fresh water use. A move to lower quality waters containing impurities such as chloride would help alleviate these pressures. In this work, we determined the uptake characteristics of weakly basic anion exchange resin Ps-EDA towards uranium from saline solutions in a dynamic flow column. Breakthrough curves were produced, with suppression of uptake being observed for chloride concentrations above 5 g L-1. Calculated resin saturation capacities at zero and 5 g L-1 chloride are comparable with literature values for strong-base anion exchange resins, and exceed those published for weak-base resins up to 20 g L-1 chloride. Data has been fitted to multiple breakthrough models, with the modified dose-response model most effectively predicting uranium recovery. The results show that the ethylenediamine functionality could be suitable for use in future uranium processing flow sheets where a high-saline lixiviant is used. IntroductionIon exchange (IX) is a key technology in the uranium mining industry and is well established for the extraction of uranium from both acidic and alkaline leach liquors (Edwards and Oliver, 2000). It was first employed in 1952 at the West Rand mine in South Africa (Ford, 1993; Taylor, 2016). H2SO4 and Na2CO3 are the most commonly employed lixiviants used to solubilize uranium in acidic and alkaline leach conditions respectively. The chemistry of these systems causes uranium to form anionic sulphate or carbonate complexes, which can be taken advantage of by anion exchange resins.Another major technology for the extraction and purification of uranium from leach liquors is solvent extraction (SX). This technique involves the extraction of uranium from the aqueous phase into an immiscible organic layer. Although this is a commonly used method, there are major drawbacks to it, including the use of large volumes of flammable solvents, solvent loss, phase disengagement, third phase formation, and the production of problematic degradation products (Veliscek-Carolan, 2016). These problems can be circumvented through the use of IX resins."

Dec 1, 2018

By B. Geelhoed

A generalization of Gy?s 1979 model for the variance of the fundamental sampling error has been proposed at WCSB2?2005 by Geelhoed. This generalized model can potentially lead to a better correspondence with actual sampling processes. However, a new parameter is required by the new model: ?the parameter for the dependent selection of particles?(Cij). It is important that this new parameter, which is at the basis of the new theory, is well understood in the sampling and blending community. In order to clarify the meaning of Cijand to prevent potential misinterpretation of Cij, we discuss the difference between Cij and an intuitively associated, but different, parameter: ?the parameter for the dependent selection of particle types?(Mij). In this contribution, the theoretical difference between both parameters is clarified. Simulations demonstrate that, numerically, the difference between Cij and Mij can be large. Some additional advantages of the approach which uses Cij are discussed: (i) the approach based on Cijis more general; (ii) in all cases where Mij is known, Cij can be determined as well, while the reverse is not true; (iii) an equation already exists that relates the sample variance to the value of Cij.

Jan 1, 2009

By G. E. Blight

Several aspects of the behaviour and properties of backfills consisting of cemented cyclone underflow tailings are illustrated by means of examples, and guidelines are given on the optimization of the performance of cemented fills. The stretch characteristics of the geofabric used to contain freshly placed backfill are described, as well as the relationship between these characteristics and the forces acting on retaining barricades. The properties required to achieve a self-supporting, stable free face in cemented backfill are explored, and a graphic relationship between stable height and shear strength is presented and compared with that for uncemented (classified) tailings. After a description of the characteristics of Witwatersrand quartzite gold-tailings backfill and commonly used cements, the process of drainage and air entry into backfill is outlined. Following this, the early-age gain in strength and the shear-strength characteristics, as well as the compressibility characteristics of cemented backfill, are described. Two phenomena that are potentially damaging to cemented backfill are seismic effects (or blasting acceleration) and the closure that takes place during the curing of cement. Investigations show that neither of these phenomena is actually significantly deleterious to gold-tailings backfill: liquefaction does not Occur as a result of seismicity, and hydration of cemented fill is not significantly impeded by closure.

Jan 1, 1996

By R L. Bowers, D S. Smit

In light of soaring commodity prices, Nkomati has investigated the potential of processing additional low grade nickel ores to add to their reserves. The Chromititic Peridotite Mineralised Zone (PCMZ) was identified as one ore type with the potential of producing a high grade nickel concentrate. In addition to the nickel, copper, cobalt and PGM?s, the ore also contains a significant amount of chromite which adds substantial value to the project. Pyrrhotite, pentlandite, chalcopyrite and chromite are the dominant minerals within the ore, which on average grades around 0.23% Ni and 12% Cr2O3. The PCMZ ore contains excessive amounts of fibrous silicates which makes it a challenging float, with gangue control as the key element to success. Extensive laboratory testwork, which eventually led to a pilot plant campaign, was undertaken with the aim of developing a process route for treating the PCMZ ore. Several flotation circuit configurations were tested and results from the optimal circuit indicated that a nickel concentrate grading at 8.5% is achievable at a recovery of 78%, with substantial recoveries for the copper, cobalt and PGM co-products. The chromite concentrate, grading at 45%, was extracted from the flotation rougher tailings via a spiral plant. These promising results were incorporated into the plant design and are currently being evaluated in a bankable feasibility study, which will see the current 100ktpm MMZ concentrator being upgraded to a 250ktpm PCMZ concentrator as part of Nkomati?s Phase II expansion.

Jan 1, 2007

By F. Bornman

Ore quality is declining, and the current spirals in mineral sands extraction is deemed inadequate to efficiently extract the valuable minerals. A new spiral was developed, the 117HM with the aim to extract the total heavy minerals in the order of 4.0% - 6.0% and the economic heavy minerals in the range 1.0% - 2.2% from the feed. An important measurable in the gravity concentration of mineral sands is recovery. Recovery measures how effectively the separator has extracted the valuable mineral contained in the input stream. The number of turns on the spiral trough influences the residence time of the feed slurry. A further optimisation followed with the development of the twelve-turn 117HM spiral. Four more turns were added for better recovery. The paper quantifies the effect of residence time on recovery.

Mar 30, 2026

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 N. Mulaudzi

The use of SO2/air gas mixtures as an oxidant to precipitate Mn from Co(II) leach liquors was investigated. The effects of SO2/air ratio, pH and temperature on Mn precipitation were evaluated. It was found that the use of SO2/air gas mixtures resulted in significantly higher Mn precipitation kinetics compared to using air or pure O2 alone. The SO2/air ratio was varied from 0% to 6% SO2(v/v) in air and similar Mn removals were achieved at 0.75% to 3% SO2 at pH 3. The solution pH was varied from pH 2 to pH 4; Mn precipitation did not increase considerably from pH 2 to pH 3, but increased significantly at pH values higher than pH 3. Cobalt co-precipitation also increased as pH increased, with 1% Co co-precipitation at pH 3. An increase in temperature from 30°C to 60°C also increased Mn precipitation and 100% Mn precipitated at 50°C. Cobalt co-precipitation also increased significantly with an increase in temperature. An activation energy of 25 kJ/mol was calculated from the Arrhenius plot, which is an indication that the precipitation reactions were both chemically and diffusion controlled. XRD analysis showed that Mn precipitated in the form of Mn2O3 instead of MnO2 that was predicted from thermodynamic data. SEM and XRD analysis also revealed that the precipitate consisted mainly of gypsum or bassanite (99%), with the Mn containing phase (< 1%) distributed within the gypsum phase. The co-precipitated Co reported to the Mn phase. Keywords: manganese precipitation; SO2/O2 gas mixtures; cobalt solutions.

Jan 1, 2009

By O. A. W. Strydom, J. C. M. Wethmar, P. R. Jochens, D. D. Howat

Liquidus temperatures in the Cr-Fe-Si system in the composition range representative of ferrochromium-silicide produced in South Africa J. C. M. Wethmar, B.Se. (Eng.) Rand D. D. Howat,U B.Se. (Glas.), Ph.D.. F.I.M. P. R. Joehens, Pr.Eng., M.Sc. (Eng.) Rand, Ph.D., A.I.M. O. A. W. Strydom, M.Sc., Ph.D. Alloys in the composition range of chromium, 20 to 50 per cent, iron, 10 to 30 per cent, and silicon, 25 to 55 per cent, were subjected to both differential thermal analysis and the classical quench method so that the liquidus temperatures of ferrochromium-silicide alloys could be determined. The results are presented as liquidus curves on pseudo-binary sections at various ratios of chromium to iron and as liquidus isotherms in the ternary section.

By C. Erichsen

ABSTRACT: The Berg Bock Freeway Tunnel represents the southernmost link of the "Thuringian tunnel chain" of the new freeway A71 located in the eastern part of Germany. It comprises two tubes each 2700 m in length. From north to south, it passes through the Suhl granite, the base sediments and the porphyrite of the New Red as well as the layers of the Middle Bunter. The two tunnel tubes were driven by the shotcrete method within appr. 10 months. With four tunnel faces, maximum performances totalling appr. 30 m/d were attained. Additional, supplementary demands on the safety conception, resulting from the findings from and the analysis of fire accidents in tunnels in recent years, had to be fulfilled in the execution planning at short notice. The inner lining is largely constructed using non-reinforced concrete. Reinforcement is only installed in the portal zones, in tunnel sections in less stable rock and in areas with a special cross-section as for instance cross connections and niches. ZUSAMMENFASSUNG: Der Autobahntunnel Berg Bock stellt das südlichste Glied der "Thüringer Tunnelkette" auf der Autobahn A71 dar, die im Osten von Deutschland liegt. Er besteht aus zwei Röhren von je 2700 m Länge. Vom Norden nach Süden durchörtert er den Suhler Granit, die Basissedimente und den Porphyrit des Rotliegenden, sowie die Schichten des Mittleren Buntsandsteins. Die beiden Tunnelröhren wurden in Spritzbetonbauweise in einer Bauzeit von etwa zehn Monaten aufgefahren. An vier Vortriebsorten wurden Spitzenleistungen von insgesamt etwa 30 m/d erzielt. Ergänzende Anforderungen an das Sicherheitskonzept, die sich auf der Grundlage der Auswertung der in den letzten Jahren aufgetretenen Brandunfälle in Tunneln ergeben haben, wurden im Rahmen der Ausführungsplanung kurzfristig berücksichtigt. Die Tunnelinnenschale wurde weitgehend aus nicht bewehrtem Beton hergestellt. Nur in den Portalzonen, in Tunnelabschnitten mit weniger standsicherem Fels und in Bereichen mit speziellen Querschnitten, wie beispielsweise im Bereich von Querstollen und Nischen, wurde bewehrter Beton ausgeführt. RÉSUMÉ: Le tunnel d&apos;autoroute de Berg Bock représente le plus méridional maillon de la "chaîne thuringienne de tunnels" sur l&apos;autoroute A71 dans l&apos;est de l&apos;Allemagne. Il se compose de deux tubes d&apos;une longueur de 2700 m chacun. Du nord vers le sud, il traverse le granit de Suhl, les sédiments de base et le porphyrite du Rotliegendes, aussi que les strates du grès bigarré intermédiaire. Les deux tubes étaient creusés en méthode de construction de béton projeté dans une période de construction d&apos;environ dix mois. À quatre fronts de taille rendements maximaux collectifs d&apos;environ 30 m par jour étaient obtenus. On a eu égard à court terme dans la conception d&apos;exécution à des demandes supplémentaires vers la conception de sécurité, qui ont résulté sur la base de l&apos;interprétation des accidents d&apos;incendie dans des tunnels dans les années dernières. La paroi intérieure était construite largement de béton non armé.

Jan 1, 2003

By T. F. Muller

In recent years, a great deal has been written and spoken, both in our country and overseas, about the dangers posed to the environment and the ecology by mining operations. The object of this address is to put this problem, and it is a real problem, into reasonable perspective. I shall try to present the various facets that merit consideration as objectively as possible. In doing so, I shall examine the following factors: Book review National Coal Board. Gate belt conveyors. London, H.M.S.O. (Price 95p.) Although the preface of this handy little book states that it has been written for the guidance of miningoperation trainees, it will prove valuable to the practising engineer as well. NIM reports Report no. 1733 A mineralogical investigation of weathered carbonatite from Salpeterkop. (14th Apr., 1975; re-issued 28th Feb., 1978). Report no. 1823 The recovery of gold and pyrite from a residue dump at Crown Mines. (10th Jul., 1976; re-issued 28th Feb., 1976). Report no. 1829 An investigation of weathered carbonatite from Salpeterkop. (20th Jul., 1976; reissued 28th Feb., 1978). Report no. 1932 A BASIC computer programme for the evaluation of intensity data from the Telsec Lab-X-250 Analyser. (12th Jan., 1978). Report no. 1940 The extraction of the noble metals with n-octylaniline, and its application to the analysis of platinum-bearing materials. (30th Jan., 1978). Report no. 1945 Analyses of the NIMROC reference samples for minor and trace elements. (28th Feb., 1978). Report no. 1945 Analyses of the NIMROC reference samples for minor and trace elements. (28th Feb., 1978). International futures conference A conference entitled &apos;The Road Ahead&apos; is being organized by the 1820 Settlers National Monument Foundation to be held in Grahamstown from 3rd to 7th July, 1978. Conference of metallurgists The technical programme has been established for the 17th Annual Conference of Metallurgists sponsored by the Metallurgical Society of the Canadian Institute of Mining and Metallurgy. This year the Conference will be held in Montreal, Quebec, on 27th to 31st August, 1978, together with the 8th Hydrometallurgy Meeting.

Jan 1, 1978

By G. A. Bezuidenhout, J. P. T. Kapusta, D. K. Chibwe

"Peirce-Smith converters (PSCs) are extensively used in the copper, nickel, and platinum group metals industries to remove iron and sulphur from the molten matte phase. This technology has not changed significantly since its inception in the early 20th century. The typical converting operation involves lateral purging of air/oxygen-enriched air into molten matte through a bank of tuyeres. This blowing operation occurs at low air pressure from the blowers, and the induced bubbling regime is considered inefficient from both a process and an energy utilization perspective. Inherent drawbacks include recurrent tuyere blockage, inevitable tuyere punching operation to clear airways, and low oxygen efficiency as a result of substantial air losses due to leakages.Investigations in the 1980s demonstrated1 that jetting into Cu and Ni converters could reduce or eliminate some of the process difficulties. In spite of these findings, very little progress has been made in the application of these concepts for converting of non-ferrous melts on a commercial scale.As part of its operational improvement and energy reduction initiative, Western Platinum embarked on a full-scale industrial evaluation of generating a jetting regime by using sonic injection. Prior to full-scale industrial evaluation, a numerical assessment was conducted to ascertain the feasibility of implementing sonic injection on Lonmin converters. The work included flow characterization at high injection pressures achieving sonic velocity at the tuyere exit. The 2D and 3D simulations of the three-phase system were carried out using the volume of fluid (VOF) and realizable k- e turbulence models to account for the multiphase and turbulence nature of the flow, respectively. These models were applied using the commercial CFD numerical code FLUENT.This paper discusses the key findings regard ing understanding of gas plume extension, velocity distribution, shear wall stress analysis, and phase distribution characteristics in the system. Plant trials are also discussed with reference to the commercial aspects of a fullscale implementation of sonic injection in the smelter."

Jan 1, 2014

By S. Asokan, Ch. V. G. K. Murty, R. Upadhyay

Zircon (ZrSiO4) is the most frequently found zirconium ore occurring in heavy mineral sands, from which it is extracted as a co-product in the production of ilmenite and rutile. Estimated world reserves of zircon are 124 million tonnes, highest in Australia (around 56 million tonnes), followed by Mozambique (15 million tonnes), India (12.6 million tonnes) and South Africa (12million tonnes). Zircon finds its application in ceramics (54%) and refractory industries (14%), which account for 68% of zircon?s total world consumption of 1.20 million tonnes. The rest (32%) is consumed in foundry, TV glass, zirconia chemicals and other applications. It is a long recognized feature of the zircon industry that supply is totally dependent upon the concurrent production of titanium minerals. But in recent years, several new developments such as the discovery of zircon-rich mineral sands in Australia, the continuing trend of higher prices of zircon and increase in trade of lower quality zircon have changed the scenario. These factors have prompted more intensive efforts to increase the recovery of zircon, particularly in the process for separating zircon from alumino-silicate minerals. Tata Steel?s proposed heavy mineral sands deposit contains on an average 10% heavy mineral content and 15% slimes of the size below 63 micron. Mineral assemblages of the resource contain65?70% ilmenite, 4?6% rutile, 4% zircon, 16% sillimanite and other minor minerals. Wide size range and tenacious iron oxide coating are the inherent characteristics of this deposit. High concentration of sillimanite among the non-magnetic heavy minerals and heavy surface coatings on the minerals are challenges for high recoveries and production of premium grade zircon. This paper outlines various process steps that were taken at pilot plant stage to produce zircon of premium grade and subsequently develop the appropriate flow-sheet.

Jan 1, 2007

Sampling In The Coal Industry Exploration, Mine, Met and Environmental Sampling EMMES 2005 3, 4 November 2005

Jan 1, 2005

By A. García-Gutiérrez, A. Aragón-Jerónimo, R. Salazar-Mendoza

A theoretical analysis of a two-region solid-liquid flow system in horizontal pipes is presented, which considers a stationary bed of drill cuttings as a porous medium (-region) below of a two-phase dispersed flow (-region).The method of volume averaging was applied in this study to derive a rigorous mathematical model in which each variable is precisely defined. This model includes the volume-averaged transport equations for both the two-phase dispersed flow and the porous medium regions and terms from a macroscopic forces balance. The solution of the two-region model allowed evaluation of the behaviour of pressure gradient as a function of velocity, total volume fraction of cuttings and the relationship of the height of the stationary bed and pipe diameter. The solution is based on a backward finite difference explicit scheme. The simulated physical system is a pipe of 4.135 m in horizontal length and 0.0508 m in diameter. A one-dimensional, mesh-centred grid, consisting of 100 nodes, is used. The numerical results were compared with experimental data on slurry flows and a good agreement was found. Keywords: two-phase, cuttings transport, solid-liquid flow, drilling modelling, volume averaging.

Jan 1, 2007

By H. M. Friede

Mining was a widespread economic activity in the African Iron Age. This paper reviews the available evidence on, the archaeological, historical, ethnological, and technological aspects of early mining in the Transvaal. A number of analyses of ores found at archaeological sites (especially at Broederstroom) are reported, and an interpretation of the analytical results is suggested. Descriptions of Iron Age copper- and tin-mining complexes, and of iron-ore workings, are given, and techniques of Iron Age mining are discussed. The evidence of gold mining in Iron Age Transvaal is examined.

Jan 1, 1980

By J. P. Hoffman

In 1988 the Japan Iron and Steel Federation started a research-and-development programme known as DIOS (direct iron-ore smelting). Eight Japanese integrated steel producers and the Coal Mining Research Centre, subsidized by the Ministry of International Trade and Industry, are involved in the project. The aim of the programme is to have a 500 v/d pilot plant for the production of iron via an oxygen-coal in-bath smelting converter in operation by mid 1993. The three main components of the DIOS process are as follows: ?a fluidized bed for the pre-reduction of iron-ore fumes ?in-bath smelting reduction in a converter ?off-gas reforming by the addition of coal fines. The main drive is to provide a smelting process that is more energy-effective, using coal instead of coke and/or electricity. The advantages claimed include inter alia ?direct use of fine iron ore ?direct use of non-coking coals-low coal consumption ?low capital expenditure-replaces costly coke ovens, agglomeration plants, and the blast furnace ?economical production on mini-plant scale ?less of an impact on the environment. This concept of &apos;direct steel has been carried over to the production of stainless steel direct from the ores, again bypassing such energy-intensive units as the submerged-arc furnace for the production of ferrochromium. A number of Japanese companies have indicated a certain amount of success. Several interacting elements are recognized that could have a productivity-limiting aspect. The possibility of the direct production of stainless steel from chromite is discussed briefly with reference to the Highveld of the eastern Transvaal as a possible site for such a plant

Jan 1, 1992

Contribution by W.D. Ortlepp? The authors are to be commended for publishing their interesting view of an aspect of deep-level mining technology that is becoming increasingly topical and vitally important. This is the second paper in the journal within four months to deal with the crucial needs of highly stressed tunnel construction, the other being the paper on the design and testing of rockburst support in the February 1994 issue. Both papers re-examine important innovative ideas that are more than a quarter of a century old, but that have not yet been implemented by the industry. It is to be hoped that they will now, taken together, serve as a new starting point for a definitive examination of what constitutes proper tunnel-support design. There can be no question that the need to develop a design approach that will solve the problems of tunnelling at depths of 4000 m or more has now become crucial. Contribution by A.M.J. Vervoort* Although the overall paper is very interesting and the future research (comparison between numerical simulations and underground measurements) will be very challenging, I would like to make some remarks regarding the set-up of the numerical model and the interpretation of the elastic results.

Jan 1, 1995

By F. Hees, A. H. Bracken, L. I. Boshoff

"Biological cementation of the Mandena heavy mineral sand deposit in Madagascar was causing difficulty in dredge mining and hence in planning and control of production rates. An investigation was initiated to better evaluate the geotechnical properties of the orebody by defining the distribution and geotechnical properties of the cemented strata, in order to generate a site-specific geotechnical model for the deposit. The geotechnical characterization was developed by an integrated approach using several ground investigation techniques such as piezocone (CPTu) testing, geotechnical drilling, standard penetration testing (SPT), as well as laboratory testing. The final outcomes of the investigation included a 3D geotechnical model showing the distribution and extent of the cemented areas, as well as the typical geotechnical parameter ranges associated with each of the defined geotechnical units. The interpretations developed were incorporated into the mine and production planning to ultimately optimize operational planning and control.IntroductionQIT Madagascar Minerals (QMM) is a heavy mineral sand mining operation at Mandena, near Fort Dauphin in Madagascar. During the final planning and commissioning stages of the project, the need to fully characterize the unusual geotechnical conditions was identified and a geotechnical investigation became necessary.Nature of the problemDuring the commissioning phase it was found that mining production was being hampered by biologically cemented/indurated layers encountered within the sands. Closer inspection of the indurated horizons in the dredging face revealed that these layers contain a high loading of bacteria and fungi. It appears that the bacteria produce an extracellular (outside the cell) polysaccharide (i.e. sugar and carbon salts), which form a gelling biofilm to trap nutrients. There are a number of different bacteria. The fungi, on the other hand, produce a network of fibrous strands that bind the sand grains together. Thus both bacteria and fungi probably contribute to the ‘apparent cohesive’ strength or binding of the indurated sand (Lynn, 2008)."

Jan 1, 2017

By P. C. van Aswegen

Owing to the strategic value of organic solvents, an investigation was conducted on the reduction of solvent losses at the Buffelsfontein solvent-extraction plant. It was established that the major cause of the high solvent losses was the high content of suspended solids in the uranium pregnant solution. To improve the clarification of the pregnant solution, it was decided to replace the conventional sand clarifiers that were being used at that stage. After pilot-plant tests had been conducted, a circulatorclarifier 16 m in diameter was installed to treat 9000 m3 per day of pregnant solution containing approximately 500p.p.m. of suspended solids. The clarifier was commissioned successfully, and yielded an overflow containing approximately 80 p.p.m. of suspended solids compared to the previous value of 250 p.p.m. This reduction in suspended solids immediately resulted in a decreasing trend In losses of organic solvent, finally yielding a reduction in these losses of approximately 50 per cent.

Jan 1, 1983

By C. Musingwini, A. S. Nhleko, M. J. Mahase

"In an environment like the mining industry, which is characterized by different stakeholders with multiple objectives, multi-criteria decision analysis (MCDA) is a useful approach for optimal decision-making. The application of MCDA techniques in the mining industry has predominantly been in mine planning and related problems, although no comprehensive survey has previously been undertaken to establish the application trends. A survey of the use of MCDA techniques was therefore conducted using case studies from the literature. It was noted that often two or more methods are applied to the same problem in order to increase confidence in the solution derived. As the number of criteria and alternatives increases, some methods become inefficient. A combination of the analytic hierarchy process (AHP) method with other MCDA techniques was the most frequently used approach, indicating the efficiency of the AHP method, especially when evaluating problems with more criteria and fewer alternatives. A combination of fuzzy theory with AHP or other methods incorporates uncertainty. The findings from the survey will benefit users applying MCDA techniques to solve mine planning and related problems.IntroductionA country’s natural resources serve the needs of different groups of people within the country. These different groups are collectively known as stakeholders (Herath and Prato, 2006). Stakeholders have different needs, preferences, and expectations, which describe and define the criteria to be considered in decision-making. The options available as solutions describe the alternatives in decisionmaking theory. The criteria and alternatives have to be evaluated simultaneously when making decisions, and this is when multicriteria decision analysis (MCDA) techniques become invaluable (Herath and Prato, 2006) because the human mind is considered to be limited when solving complex and intangible problems with several criteria and alternatives (Saaty, 2007). MCDA techniques belong to a broad group of techniques called multi-criteria decision-making (MCDM) techniques. The other group of techniques within MCDM comprises the multi-objective decision-making (MODM) techniques. MODM techniques are generally used to solve problems with an infinite number of alternatives, while MCDA techniques are generally used to solve problems with a finite number of alternatives (Musingwini, 2010)."

Jan 1, 2016