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By S. P. Pereira

The mechanized mining cycle using loaders and shuttle cars had its peak in terms of usage in the mining industry during 1950 through 1960. In Brazil, this system is still used at underground coal mines in southern Santa Catarina coal basin. With the aim of investigating the benefits of a new mining scheme using the room and pillar method for these local mines, a computational simulator model was developed in order to investigate the mining cycle. This paper presents the methodology used to develop the simulator and the results that the simulation shows regarding impact of the proposed new scheme on mining productivity.

Jan 1, 2012

By E. Machaka, A. Cornah

"Mineral resources are typically informed by multiple data sources of varying reliability throughout a mining project life cycle. Abundant data which are imprecise or biased or both (‘secondary data’) are often excluded from mineral resource estimations (the ‘base case’) under an intuitive, but usually untested, assumption that this data may reduce the estimation precision, bias the estimate, or both.This paper demonstrates that the assumption is often wasteful and realized only if the secondary data are naively integrated into the estimation. A number of specialized geostatistical tools are available to extract maximum value from secondary information which are imprecise or biased or both; this paper evaluates cokriging (CK), multicollocated cokriging (MCCK), and ordinary kriging with variance of measurement error (OKVME).Where abundant imprecise but unbiased secondary data are available, integration using OKVME is recommended. This re-appropriates kriging weights from less precise to more precise data locations, improving the estimation precision compared to the base case and to Ordinary Kriging (OK) of a pooled data-set. If abundant secondary data are biased and imprecise, integration through CK is recommended as the biased data are zero-sum weighted. CK consequently provides an unbiased estimate with some improvement in estimation precision compared to the base case."

Jan 1, 2015

By A. S. Macfarlane

Mineral resource management (MRM) practice has developed in South Africa over the course of the last ten years, with the purpose of integrating previously isolated technical functions into a value chain aligned, process organization, responsible for mine planning and optimization. The implementation of MRM within various companies has met with varying degrees of success, often resulting in incremental improvements in the planning process and, conversely, often becoming the scapegoat for poor delivery on plans and projects. The reason for this has been, amongst others, a lack of a suitable metric to define the success rate of MRM in the business at hand, in terms of its contribution to the bottom line. This paper is the result of extensive research by the author into this subject, which has resulted in the conclusion that economic value added is an appropriate measure that will lead to real optimization and value creation in mining companies, if applied within a new, holistic model

Jan 1, 2006

By A. Sariisik

This study analyses the results of a pilot trial of a newly developed armed-chained stone-cutting machine. The machine was developed in Turkey and trialed at the Kaklik/Kocaba travertine quarries in the Denizli District. An armed-chained cutting machine is an alternative to the diamond wire cutting method more frequently used in the production of natural stone quarry blocks, and increases production efficiency and quality. Since there is no need to collapse the blocks using the armed-chained cutting production process, there is no risk of the block developing cracks. This results in a considerable increase in the efficiency of natural stone block production. The armed-chained cutting machine is easier both to assemble and run when compared to other block cutting methods. This process resulted in the production of a larger number of blocks at a lower cost within the same time frame, particularly in travertine quarries and in all other natural stone quarries. The block efficiency in travertine quarries was calculated as 65?80%using the armed-chained cutting machine, compared with 7?14% using the normal diamond wire cutting method.

Jan 1, 2010

By W. I. van Drunick

AngloGold Ashanti Metallurgy has recently been involved in the successful installation of intelligent, expert control systems on the milling circuits. The benefits of expert systems in these highly interactive circuits are obvious. Existing comminution tools, which have been developed and can now be incorporated into online control, include improved modelling techniques and understanding, robust and competent simulation methods, sampling techniques, and optimization methods. The minerals processing industry has seen the benefits of predominantly research-based centres turning their focus to commercial applications of comminution circuit modelling packages, which in turn can be utilized within expert control systems. Expert mill control has been successfully installed at AngloGold Ashanti South Africa?s Mponeng and Kopanang Gold Plants. Expert control has also been installed at AngloGold Ashanti?s West African Sadiola Mine operation. The implementation of the systems has produced a number of positive outcomes. Plant surveys usually result in the identification of sub-optimal areas, and the control philosophy is then configured to ensure that these areas (along with the entire circuit) are optimized and maintained. Outdated PID loops have generally resulted in oscillatory control with large amplitude deviations from set-point. Significant improvements in SAR Metallurgy operations have been realized, firstly through achieving stability in the load and cyclone control, and secondly through online identification and implementation of optimized set-point conditions for mill mass, discharge density, etc. Soft sensors are configured to accurately estimate parameters that were historically not measurable, viz. breakage rate, mill load condition, onlinekWh/t-75 microns, mill discharge density and cyclone overflow grading. The Mponeng Plant system achieved circuit stability and improved overall grind. The Plant was able to pay back the control installation after 3 months, based on the additional recovery obtained from the finer grind. The system at Kopanang Plant has also resulted in enhanced plant recovery as a result of a finer grind and a lower residue gold content. The payback for this system was calculated at approximately 6 months. AngloGold Ashanti Metallurgy is currently expanding the installation of expert control to its other operations. It is also evaluating the performance of various suppliers of advanced control systems.

Jan 1, 2005

By J. Botin

Traditional risk quantification methods provide little information on the sources of risk, and tend to produce static over-conservative evaluations, which do not account for changes in the performance of the project. Capital investment decisions for large mining projects require more complex risk evaluation models that include the value of flexibility and the different risk levels associated with uncertainty on project variables (price, grade, dilution, and production rates, among many other). In this context, real option valuation (ROV) methods have proven potential to quantify the risk associated with such variables and integrate alternative scenarios and management strategies into the evaluation process. In this paper, a risk quantification model is developed that successfully quantifies the risk associated with dilution, as a function of production rate. This model is then validated in a case study on the Chuquicamata Underground Mine project. Keywords real options, risk management, risk quantification, dilution, minine planning.

Jul 1, 2013

By B. J. Kloppers, J. V. Z. Visser, C. J. Horn

"The long-term plan (LTP) in a mineral resource company is defined by the quality of the mineral resource and represents the result of a series of trade-offs to fulfil internal organizational as well as external business and legislative requirements, ensuring ultimate delivery on the defined organizational strategy.The LTP should as a whole align to a coherent and well-defined organizational strategy, working towards a clearly defined objective while still allowing a tactical response to short-term requirements of the organization. The ability to respond tactically to changes in environment, like the unprecedented five-month strike in 2014 on the platinum belt following the 2012 Marikana incident, is a measure of the flexibility of the plan given the agreed strategy.This paper describes the Lonmin process of linking company strategy with long-term planning, tactical planning, and the execution of the plan through an annual planning cycle to maximize organizational flexibility. This flexibility enables mining companies to respond to the many internal and external forces that impact on both strategy formulation and delivery of results that meet shareholder expectations."

Jan 1, 2015

By S. Ganguly

Slag samples taken from adjacent to the furnace wall of a submerged arc ferromanganese smelting furnace have been found to contain high concentrations of K2O. To characterize the phase equilibria relevant to these slags experimental studies have been carried out to determine pseudo-ternary sections of the form ?MnO?-CaO-(SiO2+Al2O3) with a fixed Al2O3/SiO2 weight ratio of 0.65 and 6.0 wt% K2O for temperatures in the range 1523-1673 K. In the pseudo-ternary section investigated the primary phase fields are found to be mullite, 3Al2O3?2SiO2; corundum, Al2O3; spinel, MnO?Al2O3; manganosite solid solution, (Mn,Ca)O; dicalcium silicate,2CaO?SiO2; gehlenite 2CaO?Al2O3?SiO2; anorthite CaO?Al2O3?2SiO2; kalsilite KAlSiO4 and leuciteKAlSi2O6. It was found that the presence of K2O in the slag decreases liquidus temperature in the anorthite and gehlenite primary phase fields. The manganosite primary phase field is expanded in the direction of increased (Al2O3+SiO2) and the liquidus temperatures in the manganosite primary phase field are increased significantly with the presence of K2O in the slag.

Jan 1, 2007

By H A. Myburgh

The beneficiation of heavy metal oxides, such as iron ore, is usually performed with heavy medium separation in cyclones, static baths and lately with Larcodems. Atomized ferrosilicon is most suitable as a heavy medium at densities above 3600 kg/m3 whereas a mixture of milled and atomized ferrosilicon is suitable at densities below 3600 kg/m3. When operating a beneficiation plant at densities higher than 3600 kg/m3 the quality of the ferrosilicon particles is an important factor that influences the control of the beneficiation process. Therefore, it is important to know how the rheology would be affected by the ferrosilicon quality as it also influences the control of the process at these elevated densities. Background The Kumba Resources Sishen Iron Ore Mine in South Africa produces 26.5 Mt iron ore per annum from its beneficiation plant. The ore body consists mainly of laminated and massive type hematite ore that is crushed down to ?90mm before being beneficiated by means of a combination of Wemco drums, Larcodem and dense medium cyclone separators. The need for higher densities When the percentage of high-density gangue2 is higher than normal in the run-of-mine (ROM), a higher separation density is necessary to produce a product to specification. Certain ore types of this quality in the Sishen reserves require a separating density higher than 4000 kg/m3, whereas densities would normally average 3600 kg/m3 when beneficiating ores of normal high-density gangue content. Sink and float tests conducted on the ROM material at Sishen revealed some interesting characteristics. In the waste fraction, (density < 3600 kg/m3) it was found that the %Fe was <21% (Fig. 1). Similarly, for the product fraction (density >3000 kg/m3), the percentage Fe varied between 35% and 67.2%. The bulk of the material (88%) actually had a density greater than 4000 kg/m3 and a Fe content that varied between 63% and 67.2%. At a density interval of 3600 to 4000 kg/m3, the Fe content varied from 37% to 60% with an average of 45%.

Jan 1, 2006

By V. Labiouse, M. Jaboyedoff

GIS documents are of great interest for a quick and low-cost determination of areas endangered by rockfalls. They allow (i) the detection of potential instabilities from steep slopes and cliff areas, and (ii) the preliminary estimation of potential run-out areas by means of a so-called cone method. After the presentation of the tools used to compute these areas, the paper focuses on two methods developed for a preliminary hazard mapping, one at regional scale and the other at local scale. Mittels GIS-Dokumenten können von Steinschlag bedrohte Gebiete schnell und kostengünstig ermittelt werden. Die sogenannte Kegelmethode erlaubt die Erkennung potentiell instabiler Zonen von Steilhängen und Felswänden sowie eine erste Einschätzung der möglichen Reichweiten. Nach der Vorstellung der zur Berechnung der bedrohten Gebiete benötigten Hilfsmittel stellt der Artikel zwei Methoden zur vorläufigen Gefahrenkartierung in lokalem und regionalem Maßstab vor. Les SIG sont très intéressants pour une détermination rapide et peu onéreuse des zones affectées par des chutes de blocs. Ils permettent une détection des zones potentiellement instables et une estimation sommaire des zones de propagation des blocs par une méthode dite des cônes. Après la description des outils utilisés pour définir ces zones, l’article expose deux méthodologies élaborées pour un zonage préliminaire du danger, l’une à l’échelle régionale et l’autre à l’échelle locale.

Jan 1, 2003

By Helge Rosenberg

Up to now, Topsøe WSA (Wet gas Sulphuric Acid) plants have been in operation for almost 30 years, and close to 80 plants have been sold. In spite of its unique features and ability to treat gases without any prior drying, the WSA technology has had certain restrictions with regards to SO2 concentration in the feed gas, and the overall conversion of SO2 by catalytic means has been limited to approx. 99.7%. In commercial scale sulphuric acid production on the basis of elemental sulphur and metallurgical off-gases, there is a demand for higher SO2 conversion and treatment of gases with a higher content of SO2. Therefore Topsoe has further developed its WSA technology to cope with these demands. This paper will explain more about the principles of such new development and leave the delegate with a better understanding of the potentials of the new generation of the WSA technology from Topsoe.

Jan 1, 2009

By Helge Rosenberg

Up to now, Topsøe WSA (Wet gas Sulphuric Acid) plants have been in operation for almost 30 years, and close to 80 plants have been sold. In spite of its unique features and ability to treat gases without any prior drying, the WSA technology has had certain restrictions with regards to SO2 concentration in the feed gas, and the overall conversion of SO2 by catalytic means has been limited to approx. 99.7%. In commercial scale sulphuric acid production on the basis of elemental sulphur and metallurgical off-gases, there is a demand for higher SO2 conversion and treatment of gases with a higher content of SO2. Therefore Topsoe has further developed its WSA technology to cope with these demands. This paper will explain more about the principles of such new development and leave the delegate with a better understanding of the potentials of the new generation of the WSA technology from Topsoe.

Jan 1, 2009

By R. H. Estrada-Ruiz

This work analyses a new approach to estimates bubble size distribution of froth surfaces using artificial neural networks (ANN).Also, the robustness of ANN to interpret images with illumination perturbations, produced by light problems or dirt attached to the window of the video camera is evaluated. The experimental work was carried out in a laboratory flotation column, instrumented with an image acquisition system. The images were processed making use of a perceptron model with a hidden layer, sigmoidal transfer function and unitary bias, and the ANN trained with a back propagation algorithm. The results of validation show that ANN are reliable for learning and producing generalized predictions of the froth mean bubble diameter and bubble size distribution, when the model is trained using a database that contains information on the illumination intensity. Keywords: image analysis, neural networks, bubble diameter, bubble size distribution.

Jan 1, 2009

By D. C. Andersen, G. L. Smith, J. Pearson-Taylor

Following a restructuring of Anglo Platinum Limited in 2004 the strategic long-term planning function has been centralized. This paper describes the revised strategic long-term planning process covering aspects of the planning cycle, systems and methodologies, categorization of capital expenditure, corporate governance and planning tools.

Jan 1, 2006

Rockbursts continue to be a scourge in the mining industry, being responsible for accidents and damage to mining excavations. Although the problem has been present for more than a century, and although much research has been carried out, a solution is still elusive. Determination of, firstly, the demand on the support system imposed in the rockburst and, secondly, the capacity of the support system, cannot be carried out with any confidence, and therefore rockburst support cannot be designed using a conventional design approach. In contrast with the conventional approach, observations of rockburst damage in a mine have revealed a possible alternative approach to rockburst support ? sacrificial support. It was observed, in rockburst events, that a support system consisting of concrete panels restrained by grouted cables was destroyed, and the concrete panels were ejected. However, the rock behind the panels remained apparently undamaged and in place. This behaviour reignited the concept of sacrificial support, conceived more than 20 years ago, and which is described in this paper. The remedial solution implemented on the mine, involving cables wrapped over the panels and retained by grouting into boreholes, has been subjected to rockburst loading and has confirmed the validity of the sacrificial support concept. The concept of sacrificial support may be controversial, but is deliberately presented here with the aim of generating discussions and contributions, and with the ultimate aim of improving safety and reducing rockburst damage in mines. Keywords rockburst, seismicity, seismic waves, rock support, support design.

Jul 1, 2013

By B. C. Alberts

Planning the use of South Africa&apos;s energy resources, especially coal, is of the utmost importance. The State and the mining industry require reliable official estimates of the economically mineable coal reserves for planning purposes. An overview of al the previous reserve estimates is given, with specific attention to the two most recent estimates-those of Petrick and De Jager. The differences between these two estimates are highlighted. The following important aspects are discussed: . the need to update the information regarding South Africa&apos;s mineable coal reserves, . the necessity of understanding and agreement between the coal-mining industry and the State department responsible for updating the coal-reserve data, and . the importance of the specific assumptions used in the updating of the data. A downward adjustment of mineable reserve figures is proposed, and the factors that influence the meaningful exploitation of the coal reserves are discussed. A recommendation is made as to how the Waterberg coal reserve should be exploited, and it is concluded that the Soutpansberg Coalfield cannot be exploited economically in the foreseeable future. An evaluation of the status of the coal-export trade is made and compared with the assumptions and targets set at the start of the coal-exportation scheme. The comparison shows the extent to which the exploitation of the coal reserves is being negatively influenced by the current market situation. Recommendations are made regarding planning for the coal-export market, and the aspects that have to be taken into account to keep South Africa in the export market are identified. Reference is made to the fact that the present unrestrained wage and salary adjustments, which show a total disregard of South Africa&apos;s poor productivity record, require serious thought and speedy rectification if the country is to survive in the export market. A salary and wage strategy must be developed to suit the specific needs of the Republic of South Africa.

Jan 1, 1987

By C. M. Rule

Energy efficiency is currently a significant area of interest due to the Eskom power situation, which led to severe power impacts to the PGM, and indeed whole SA primary industries, in early 2008. Anglo Platinum has focused on energy efficiency for a number of years, especially in the concentrator operational area. New comminution technologies have been aggressively developed, which have shown real metallurgical efficiency gains as well as significant energy efficiency and saving potential for Anglo Platinum?s total electrical consumption as the company expands into a growing PGM demand market. This paper illustrates this programme?s activities, potential and considerable achievements to date.

Jan 1, 2009

By R. Poisel, C. Scavia, Preh A., W. Roth, M. Pirulli

ABSTRACT: Two methodologies for the three-dimensional simulation of the run out of rock avalanches are presented: one based on a granular approach and the other based on a continuum equivalent approach. An evaluation of the possible run out area of the Oselitzenbach landslide (Carnic Alps, Austria) has been carried out applying the two methodologies. The combined use of these two approaches makes it possible a comprehensive assessment of the run out area. RESUME: Deux méthodologies pour la simulation tridimensionnelle de la propagation des avalanches rocheuses sont présentées: la première est basée sur un modèle de type granulaire et la deuxième sur un modèle du continu équivalent. Une évaluation de la propagation éventuelle de l’avalanche de Oselitzenbach (Alpes Carniche, Autriche) a été réalisée en utilisant les deux méthodologies. Les résultats obtenus montrent que la combinaison des deux approches rend possible une analyse plus complète de la phase de propagation. KURZFASSUNG: Für die dreidimensionale Modellierung eines Felsmassensturzes (sturzstrom) werden zwei Methoden, eine granulare und eine kontinuumsmechanische Methode, vorgestellt. Beide Methoden wurden zur Abschätzung der Ausbreitung (runout) der Massenbewegung Oselitzenbach (Karnische Alpen, Österreich) herangezogen. Die kombinierte Anwendung beider Methoden ermöglichte eine umfassende Beurteilung des möglichen Ausbreitungsbereichs.

Jan 1, 2003

An extensive laboratory grinding study was carried out on a magnetite ore in order to assess the grinding behaviour of magnetic concentrate and tail from low intensity magnetic separation (LIMS).The test work involved Bond ball mill testing, rod milling, low intensity magnetic separation (LIMS), and batch ball milling down to product sizes of around P80~25 microns. A total of 18 Bond tests and over 150 batch grinding tests and sieve sizing were carried out. Throughout the grinding tests, power draw was continuously monitored. The relationship between the grinding energy and product size was analysed using the conventional energy-size concepts. It was found that the Rittinger equation fits the experimental data well. However, Bond?s equation does not fit the experimental data well, and therefore a modified Bond equation was developed. Differences in grinding properties between the magnetic and non-magnetic component were analysed and compared to the bulk ore. It was found that grinding properties differ significantly and therefore separate grinding test work may be required for each grinding step in the magnetite ore beneficiation flowsheet. Keywords: grinding, iron ores, particle size, modelling.

Jan 1, 2010

By T. Tholana, P. N. Neingo

"Mining companies globally are currently facing severe economic and financial challenges. In addition to global challenges, the South African mining industry has to face other operational challenges that are unique to the country and which threaten the survival and competitiveness of the industry. Profit margins are being squeezed by rising costs and decreasing commodity prices, while labour productivity is greatly affected by intermittent labour unrest. This paper analyses how the South African gold mining industry has performed pre-, during, and post the global financial crisis of 2008. The competitiveness of the industry in terms of labour productivity and industry cost curve position is analysed for the period 2006–2013 to assess the impacts of both the global financial crisis and labour unrest. An analysis of the South African gold mining industry is presented at company as well as mine level. Productivity measure in this paper is limited to labour productivity, in line with limited reporting on productivity. All the data analysed was obtained from the public domain. IntroductionSouth Africa dominated the world as the number one gold producer until 2009 when China took that position, and today South Africa ranks fifth after China, Australia, Russia, and the USA. According to Statistics South Africa (2009), South Africa still had about 30 years of production in the gold sector, a forecast that fluctuates based on the day’s modifying factors. Although South Africa has a comparative advantage in terms of minerals endowment, there are challenges faced by the mining industry that hinder translation of the comparative advantage into a competitive advantage. The industry continually seeks to address these challenges to remain competitive in global markets while addressing national and community needs.Neingo and Cawood (2014) argued that stakeholders in mining are continually concerned with mine management’s ability to translate use inputs effectively into quality outputs. They further suggested close monitoring of effective utilization of people, materials, and money to obtain maximum production of commodities under given conditions. Productivity is measured in various ways, including unit cost, output per employee, and output per unit capital equipment"

Jan 1, 2016