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By G. Nino de Guzman, L. C. Woollacott

The isotherms that are usually taken to represent the force 'driving' the adsorption in carbon-in-pulp processes may change from contactor to contactor. This paper reports on an investigation into the extent to which this Isotherm shift is Influenced by the changes in oxygen and cyanide concentration that occur in operating plants. The impact of the isotherm shift on the reliability of simulation results is examined.

Jan 1, 1993

By J. C. D. Gush

Paper written on project work carried out in partial fulfilment of Laboratory-scale testwork was undertaken to recover oxidic copper-cobalt minerals by froth flotation, which requires maintaining a certain sulphide level in the pulp. To improve control of the sulphide concentration, an electronic closed-loop system was designed that responds to the potential output of an ion-selective electrode. The PID control was improved by adding a pre-emptive control and a self-calibration feature; a data logging facility is also included. An inexpensive valve design was incorporated using locally available parts. The operating results of this control design are presented.

Jan 1, 2005

By K. Basaure, S. Palma, R. L. Castro

"Mud rushes are sudden inflows of fine wet ore within underground mines; they can harm people and equipment as well as cause production delays. Block and panel caving mines are prone to mud rushes in their production levels, with mud flowing from the drawpoints. Different mines have developed methods to control drawpoint conditions and thus perform safe ore extraction. The aim of this study is to develop a decision matrix and apply it to samples from drawpoints for the Diablo Regimiento mine, Codelco, El Teniente Division (Chile). The Abrams’s Cone was used to perform slump tests on mud samples and characterize their consistency by setting the saturation degree and packing. The unconfined strength for different saturation degrees and packing was then evaluated. The results show that conditions for fluid response in slump tests correspond to conditions for low strength in unconfined compression tests. We also found the water content value at which the flowing consistency changes from plastic to soft behaviour according to the slump test classification for each sample. This value varied between 12.2% and 16.9%, depending on the sample tested. Finally, a fluid security factor was defined in order to design an extraction pattern for the samples tested, based on the water content. We conclude that a very densely packed ore is not prone to flowing. The flow properties depend strongly on the specific properties of the ore tested, and consequently a specific criterion should be developed for different types of ore at a particular mine. The criterion developed for Diablo Regimiento ore provides critical water content values from 11% to 15%, depending on the ore type. IntroductionBlock/panel caving has the lowest cost and the highest production rates of all underground methods (Heslop, 2000; Hubert et al., 2000). Good management of the risks is important to ensure the security of personnel and infrastructure. Operational risks for the method include rockbursts, air blasts, and mud rushes (Hubert et al. 2000). A mud rush is defined as a sudden inflow of mud from a drawpoint or other underground opening into the mine (Butcher, Joughin, and Stacey, 2000; Butcher, Stacey, and Joughin, 2005). Mud rushes can cause dilution, production delays, and damage to equipment as well as injuries and fatalities. The elements necessary for mud rushes are mud-forming material, disturbances, a discharge point, and water (Butcher, Joughin, and Stacey, 2000). All these elements are present in block/panel caving mines. Mud-forming material comes from ore milled by the caving process; water comes from underground and surface sources. Drawpoints in the production level are discharge points for the mud. Finally, several types of disturbance could trigger the mud rush phenomena: blasting, earthquakes, operation of equipment (Call & Nicholas, Freeport McMoRan, and Hydrologic Consultants, 1998; Jakubec, Clayton, and Guest, 2012), arch collapse above drawbells (Butcher, Joughin, and Stacey, 2000; Butcher, Stacey, and Joughin, 2005; Jakubec, Clayton, and Guest, 2012) and ore drawing (Butcher, Joughin, and Stacey, 2000; Butcher, Stacey, and Joughin, 2005; Call & Nicholas, Freeport McMoRan, and Hydrologic Consultants, 1998; Jakubec, Clayton, and Guest, 2012)."

Jan 1, 2017

With the increased variability of today's large-scale mining operations, consistent flotation performance is important to improving and sustaining overall recovery through the circuit. The Newcrest Telfer Mine has implemented advanced process control technology to obtain stable level operation and consistent mass pull in the copper rougher and scavenger flotation circuits. The final result has been an overall reduction in variability, which impacts on both copper and gold recovery. This paper describes the methodology and implementation of the improvements in control at the Newcrest Telfer Mine as being an essential part of the business for minerals processing.

Jan 1, 2007

By G. Raspa

The paper describes a computer procedure for evaluating and selecting recoverable reserves in a mine worked by sublevel stoping. The boundaries of the volume to be mined are optimally defined by means of the 3-dimensional Lerchs-Grossmann algorithm, separately applied to both sides of the panels. The procedure, which has been developed for Masua Mine (Sardinia), also provides for smoothing the optimized boundaries, positioning the drilling drifts, interactive design of drilling fans and calculation of tonnage and grade of each volley. These tonnages and grades form the input of another procedure evolved for production planning.

Jan 1, 1987

By O. Bazhko

Regular analysis of different streams is important for the control of hydrometallurgical processes. Various physical and physical-chemical methods are applied for this purpose. Many modern methods require costly equipment and are subject to interferences. Therefore, redoxtitration methods remain of interest. The use of different types of oxidizing and reducing agents as well as redox indicators enables many cations and anions to be rapidly and accurately analysed. Sometimes redox titrations require the prior preparation and addition of masking agents. Selective, sensitive and low-cost methods of redoxtitration of copper and SO2 in plant conditions are described.

Jan 1, 2009

By k. Lebecki, S. Trzcionka

The prototype and test results of the instrument for quick determination of incombustible content in deposited dust as a protection against coal dust explosion propagation are presented. Presently existing methods do not permit to obtain quick information about incombustible content, needed for the proper protection of workings. As the operating principle for the e instrument the dependence of reflection of infrared radiation intensity on incombustible content in the sample is chosen. The construction is based on the modern electronics. The measurement will be done at the sampling site. The range of the instrument is 0-100% of incombustible, direct reading, autonomous supply, weight no more than 0.5 kg, and is intrinsically safe according to EN Standards. During the Conference the instrument will be commercialized.

Jan 1, 2003

By R. K. Brummer

A simplified two-dimensional plane strain numerical technique for the non- linear modelling of a tabular mining excavation in brittle host rock under high stress conditions is described. The model has been developed using relatively straightforward assumptions based on extensive underground investigation of the fracturing and deformation of rock at the stope face in deep gold mines on the Witwatersrand, together with observed rock behaviour under laboratory conditions. The reef rock is modelled as a linear string of yielding elements which interact horizontally, while the elastic rockmass remote from the reef is modelled using boundary element techniques. This elementary technique is shown to produce results which agree closely with the observed behaviour of the fractured rock during the mining of a remnant pillar

Jan 1, 1987

By T. Marsden

The demand for continuous improvement in the industrial world is an ongoing process. Some sectors, where the competitive forces are well established, have led the development of new and reliable technological innovations. Although the metallurgical industry can rightfully be proud of its process improvements, there is still work to be done in materials and in material handling. In some cases, the improvements will be as simple as adopting technologies that have been perfected in other processing or manufacturing industries. This paper discusses the next design generation for copper tankhouses which will yield: ?Improved copper quality ?Improved equipment availability ?Lower life cycle costs ?Safer operations. These benefits will be realized through new developments and design improvements in: ?Permanent cathodes ?Cathode washing ?Cathode stripping machines ?Anode preparation machines ?Improved lead anode design ?Recycling of lead anodes and refurbishment of cathodes. The demand for base metals, and in particular copper, has led to more research into improving efficiencies in electrowinning and refinery plants around the world. One of the areas previously taken as a matter of course was the production of lead anodes and stainless steel cathodes. In South America alone there are over 600 000 cathodes and anodes in circulation?a very significant figure.

Jan 1, 2009

By G. Lyman

The cross-belt sampler is a device that is very widely used even though it has not been ratified by the Standards associations. This paper is concerned with the bias testing of two cross-belt sampler designs against stopped belt samples and a cross-stream cutter at the belt end. The bias analysis is carried out using size distribution as the analyte and conventional t-testing and the Hotelling T squared test, which are compared for their effectiveness. The paper considers the issue of detectable bias and the statistical planning of bias tests.

Jan 1, 2009

By M. Pötsch, W. Schubert, A. Goricki

Geological and geotechnical data are essential for the design of tunnels. To determine the rock mass behavior and the support of a planned tunnel excavation a consistent method for rock mass characterization and excavation and support determination has been developed. Probabilistic data processing with analytical methods is used for the quantification of the procedure and allows an evaluation of the applicability and the technical risk of different excavation and support methods. The sensitivity of the procedure on selected input parameters is highlighted in a parametric study. Finally an application of the procedure illustrates the use of the described method of probabilistic excavation and support determination for tunnels. Des données géologiques et géotechniques sont décisives pour la planification d’un tunnel. Pour la détermination du comportement des strates, le choix du soutènement et de la méthode de progression une description compréhensible de la montagne a été développée. À l'aide d'un traitement de données probabiliste, la procédure proposée est transposée quantitative sur une base de méthodes analytiques. De cette manière l'évaluation des méthodes de construction et la détermination du risque technique deviennent possibles. La sensitivité de la procédure de différents paramètres d'entrée est représentée dans une étude de paramètre. Pour finir, l'application de la procédure décrite est montrée à l’aide d'un cas pratique. Geologische und geotechnische Daten sind entscheidend für die Planung von Tunnels. Für die Ermittlung des Gebirgsverhaltens und der Festlegung von Ausbruch und Stützung wurde ein nachvollziehbarer Ablauf der Gebirgsbeschreibung entwickelt. Mit Hilfe von probabilistischer Datenverarbeitung auf Grundlage analytischer Methoden wird die vorgeschlagene Prozedur quantiativ umgesetzt. Dadurch werden die Bewertung von Baumethoden und die Ermittlung des technischen Risikos ermöglicht. Die Sensitivität des Verfahrens von einzelnen Eingangsparametern wird in einer Parameterstudie dargestellt. Abschließend wird anhand eines Beispiels die Anwendung des beschriebenen Verfahrens gezeigt.

Jan 1, 2003

By S. T. L. Harrison, A. Kotsiopoulos, J. R. Amaral Filho, J. L. Broadhurst

The land disposal of voluminous fine-grained tailings from the processing of mined ore bodies poses a long-term risk to the surrounding environment and local communities, while also representing a loss of valuable natural resources; including water, land and mined minerals. To date, the development and practical implementation of alternative approaches and technologies for removing risk and reducing the burden associated with these wastes, particularly in South Africa, remains limited, and value recovery is largely limited to the extraction of precious metals. To this end, researchers at the University of Cape Town have developed a programmatic multi-phased approach to explore and develop opportunities for the valorisation of large-volume mine wastes, based on the innovation value chain. This paper outlines this conceptual approach and presents key outcomes from its application for the specific case of sulfide-bearing coal processing wastes from South African collieries. Through the application of a combination of qualitative and quantitative tools and methodologies, a number of potentially viable opportunities and processing routes for value recovery and bulk re-purposing of these wastes have been identified and tested on a laboratory scale. Studies have, however, also shown that there are several technical and non-technical factors currently constraining commercial application of these opportunities. Overcoming these constraints will require a commitment to innovative waste management approaches and effective multi-sectoral collaboration. Keywords: Coal processing wastes, physical separation, waste re-purposing and utilisation, technology transfer

Jan 1, 2020

Professor R.F. Sandenbergh matriculated at Germiston Afrikaans High School, and then he obtained the degrees of B.Eng. (Chem.) in 1972, M.Eng. (Chem.) in 1975, and D.Eng. (Met.) in 1983-all from the University of Pretoria. Mr J.A.D. Britz matriculated in 1958 at the Roodepoort Hoerskool, and joined the mining industry in 1959 as a student mine official at the Rand Mines Training Centre. Mr J.A. Cruise matriculated at Durban High School and joined Union Corporation as a Learner Official in 1962. He was awarded a scholarship to read for B.Sc. and M.Sc. degrees in mining engineering at the University of the Witwatersrand

Jan 1, 1990

By P. Geldenhuys, D. J. C. Taylor, D. C. Page

This paper gives a technical review of the history, occurrence, mining, and metallurgy of iron in South Africa. The reserves of iron ore worldwide and in South Africa are reviewed, and potential new developments In the iron-and-steel industry in South Africa are examined. The paper concludes that the exploitation of lower-grade iron deposits will probably supplement the reserves of high-grade hematite ore in the distant future, and that, accepting this scenario. South Africa will be well placed to provide iron ore for its expected internal steel requirements, as well as supplying quality Iron ore for the export market.

Jan 1, 1988

By M. J. U. T. Van Wijngaarden, R. J. Dippenaar

An electrochemical technique based on the solid oxide galvanic cel Mo / Mo + MoO2/ ZrO2-MgO / Fe + (FexO)slag + Ag / Fe was used in a determination of FexO activities in liquid slag systems. The emf measurements, scanning electron microscopy, and microprobe analysis of the cross-sections of the electrolyte tubes used in direct contact with the slag melts indicated that slag attack did not affect the open-circuit emf values during normal cell operation, The reliability of the cell was confirmed by the good agreement between the standard free energy of formation of liquid Fep obtained in the present study and those reported in the literature, The FexO activities were determined in FexO -CaO and FexO-SiO2 slags at 1673 K, and are in good agreement with those measured by the conventional gas-equilibrium technique. The experimental technique was successfully extended to the measurement of Fe2O activities in the complex slags that are used for the external desilliconization of the hot metal product of the blast furnace.

Jan 1, 1986

By I. M. Macleod

An adaptive steady-state on-line optimizing regulator is proposed as an integrated approach to the control of autogenous run-of-mine milling circuits. This optimizing regulator continuously estimates an internal model of the controlled process, and, based on this, determines mill fresh solids feed rate, mill water flow rate and sump water addition flow rate such that a circuit performance objective is optimized. The dual -requirement of controlling both the mill pulp load and the load of particles of grinding media size is thus directly and simultaneously addressed. The concept and theory underlying the operation of the adaptive optimizing regulator are discussed.

Jan 1, 1987

By C. G. Carey, M. P. Mullins

BHPBilliton is a large (US$32bn market capitalization) diversified mining group. Significant organic growth is planned through the development of a number of mining, processing and oil and gas projects, totalling some US$5.2bn over the next three years. The investment standards underpin the capital approval process, and incorporate the requirements for range and risk analysis of key input variables, including mineral resources. Public reporting codes for mineral resources and ore reserves (such as JORC) stipulate deterministic reporting of estimates, but are generally silent on any requirement for range or risk assessment, although they acknowledge the risk and uncertainty in the production of resource estimates. In contrast, public reporting of petroleum reserves allow for the use of either deterministic or probabilistic estimation, and for the latter, mandate the level of confidence required for proven versus probable reserves. Conditional simulation techniques, popular in the petroleum industry, provide an ideal tool forrange and risk assessment of the range of outcomes of key resource parameters, such as tonnagesand grades. Examples of a diamond deposit and of a porphyry copper deposit are presented. The understanding and quantification of mineral resource risk through a technique such as conditional simulation provides quantified information on the potential upside or downside. These techniques should be more widely utilized in the high-risk minerals extraction industry. Keywords: mineral resources, conditional simulation, risk, capital investment standards, BHPBilliton.

Jan 1, 2003

By P. Otto, G. Borm, Th. Dickmann, F. Amberg, R. Giese

Based on many years experience, the well proven Swiss Tunnel Seismic Prediction System TSP has been substantially augmented for online geological prognosis in underground construction. In its latest version, the Integrated Seismic Imaging System ISIS provides high resolution seismic images of the rock mass around a tunnel face via an array of standard anchor rods. These rods contain 3D-geophones at their tips and can be readily installed during excavation work. A further innovative component of the system is the newly developed high-power repetitive source for application in hard rock: a pneumatic hammer with laser triggering to be mounted on construction machinery. A user-friendly software package permits online data acquisition and processing, 3D-visualization, and a first geological interpretation. Tomographic images of compressional and shear wave velocity fields at fault zones in metamorphic rock of the Gotthard Base Tunnel in the Central Alps are presented. Das langjährig bewährte Schweizer Tunnelseismische Vorauserkundungssystem TSP wurde inzwischen wesentlich weiterentwickelt. In seiner neuen Version, dem Integrierten Seismischen Imaging System ISIS, ermöglicht es hochauflösende seismische Abbildungen des Gebirges im Vorfeld und Umfeld einer Tunnelauffahrung mit Hilfe einer Anordnung von Felsankern, die an ihren Spitzen 3-Komponenten-Geophone enthalten. Eine weitere Neuerung von ISIS ist die pneumatische Hochleistungs-Impulsquelle mit Laser-Triggering. Eine benutzerfreundliche, interaktive Software ermöglicht die online Datenerfassung und -auswertung, 3D-Visualisierung und eine erste geologische Interpretation. Tomografische Abbildungen von Kompressions- und Scherwellengeschwindigkeitsfeldern an Störungszonen in metamorphem Gestein des Gotthard-Basistunnels werden gezeigt. Basé sur de nombreuses années d’expérience, le système suisse, bien établit, de reconnaissance sismique à l’avancement des tunnels (système TSP), a été sensiblement amélioré pour obtenir une prévision géologique en temps réel durant l’avancement de travaux souterrains. Sa dernière version, le Système Intégré d’Imagerie Sismique (ISIS), fournit des images sismiques haute-résolution du massif rocheux à l’avant d’un tunnel grâce à un réseau de tiges d’ancrage standard. Ces tiges, équipées à leur extrémité de géophones 3 composantes, s’installent très aisément durant les travaux d’excavation habituels. Le élément d’innovation récente concern le nouvelle source très répétitive et de forte puissance pour les applications aux roches dures: un marteau pneumatique déclenché par un système à laser. Un ensemble de programmes informatiques convivial permet l’acquisition et le traitement en temps réel des signaux et produit une vue 3D ainsi qu’une première interprétation géologique. Nous présenterons des images de réflexion d’ondes de compression et de cisaillement ainsi que des inversions tomographiques de zones de faille dans des terrains métamorphiques obtenues à l’occasion du creusement du tunnel de base du Gothard, dans les alpes centrales.

Jan 1, 2003

By L. H. W. Walker

As part of an overall design of a computer based mining managerial system, the geological and mineral estates management disciplines find themselves centrally placed in terms of producing fundamental data both before and during the mining operation. Computerisation of all aspects of these fields of endeavour has come to be seen as essential for complete integration with other mining orientated disciplines. Release 1 .l. of the Anglo American system of mineral estates management has been tested and is in the process of being implemented at several Anglo American Gold Division mines.

Jan 1, 1987

By M. B. Cortie

The historical development of materials engineering in the mining industry Is briefly reviewed, and some of the factors currently influencing the industry in South Africa are discussed. Material usages in various parts of the mining operation are surveyed. The predominant mechanisms in the degradation of materials in mines are wear, corrosion, and fatigue. The issue of corrosion-abrasion Is considered, but it Is concluded that abrasive wear predominates in most rock-handling and comminution applications and that, in general, little economic benefit Is to be gained in those applications by the use of existing corrosion-resistant alloys. However, alloys with a measure of corrosion resistance find profitable application elsewhere in the mining environment. The use of other engineering materials such as polymers, ceramics, al1l1inium, and various ferrous alloys may be economically viable in a variety of niche situations. Identification of the most cost-effective material in each case calls for a systematic approach and some patience.

Jan 1, 1996