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By J. M. Cardoso, E. F. Quadros, A. Chiarini, F. Fernandes, G. Vilela, J. Ireno, L. C. Agostini

Based on the geological-geometric characterization of the basaltic rock at the site of a factory for chemical products situated in the Southern region of Brasil, and on results of a significant number of packer tests, the principal directions of flow were estimated, taking into consideration the intersection and the orientation of the joints and the amount of contaminant flow measured in each interval. The tests were performed using the multi-packer hydraulic multitest probe of IPT (HMTP) instrumented with an electric conductivity meter. A method of analysis for three-dimensional evaluation of the amount of contaminant flow in the area was proposed for future mitigation of the problem. Basé sur une caractérization géologique-géotechnique de la roche basaltique existant sur un site dune fabrique de produits chimiques située au sud du Brésil et sur les resultants dún nombre significantif déssais du type packer, les directions principales d´écoulement ont été estimées en considerant l´intersection et orientation des joints et la quantité de contaminant mesurée sur chaque intervale d´essais. Ceux-ci ont été realizes en utilisant une sonde multipacker developée au IPT – São Paulo (HMTP) instrumentée avec un mesureur de condictivité électrique. Une méthode d´analyse 3-D pour l´évaluation du transport du contaminant sur ce site a été proposée pour une future mitigation du problème. Auf Grund der geologischen Struktur des Basalts auf dem Gelände einer chemischen Fabrik in Südbrasilien und der Ergebnisse einer ansehnlichen Zahl von Pumpversuchen wurden die Hauptfließrichtungen bestimmt unter Berücksichtigung des Kluftgefüges und der in jedem Intervall gemessenen Menge kontaminierten Wassers. Die Versuche erfolgten mit dem im IPT entwickelten Verfahren (HMTP) mit Mehrfachpackern und elektrischen Leitfähigkeitsgebern. Ein analytisches Verfahren zur dreidimensionalen Ermittlung der Mengen kontaminierten Wassers wurde für die künftige Befassung mit dem Problem entwickelt.

Jan 1, 2003

The Iscor Board has given its Mining Division the authority to proceed with detail engineering and design for a Heavy Minerals Project which comprises a mine in Northern Province near Gravelote, a mine in KwaZulu/Natal near Richards Bay and a central processing complex with a beneficiation plant and smelter which will be located near Richards Bay and Empangeni.

Jan 1, 1996

By C. A. Ozturk

The compressive strength of rock (sc) has an important effect on design of structures in rock engineering. Compressive strength can be determined in the laboratory using the uniaxial compressive strength (UCS) test. Some other index tests, such as the point load test, are also used, particularly when suitable samples for UCS are not available. The quantification of rock texture has introduced a new method in rock engineering for estimating the mechanical and physical properties of rock materials from microscopic investigations. The aim of this study is to quantify rock texture to estimate rock strength from the texture coefficient (TC), which is determined from a statistical assessment of thin section images. Rock texture is quantified by twelve different images from a single thin section to increase the reliability of texture analysis. A data-set is prepared to investigate correlations between TC and sc. The statistical correlations are computed after classifying of the rock samples based on their lithology as well as grain features. Equations derived based on the results of this study are used to predict the approximate value of compressive strength from the texture coefficient. This method is particularly useful for preliminary studies in rock engineering projects prior to detailed site investigation.

Jan 1, 2014

By A. Kostin

GIS and multivariate geometric distribution have been used to predict the association of high-level intrusives with hydrothermal alteration related to iron oxide Cu-Au (IOCG) mineralizing systems. Several examples in the Russian northeast are presented in this paper. IOCG ore deposits can have enormous geological resources containing significant reserves of base, precious, and strategic metals, and hence are economically attractive targets for mineral exploration. To date, examples of this type of mineralization have not been reported from the northeastern area of Russia. The Tarinskiy ore cluster, located in Eastern Yakutia, shows brecciated altered rocks with sulphide and iron oxide cement, which is typical for IOCG mineralization of the iron oxide Cu-Au±U type. This cluster was formed near surface and is linked with the Rep- Yuruinskiy pluton. It has potential to host new world-class precious metal deposits in northeastern Russia

Jan 1, 2014

By J. W. Joubert, R. C. W. Webber-Youngman, M. D. Budeba

"SynopsisCost estimation for surface coal mines is a critical practice that affects both profitability and competitiveness. New mines require these costs to be estimated using available information before a project begins. The competitive advantage of a new mine depends on it being both efficient and cost-effective. Low-cost producing mines have a higher chance of survival in a low-price environment than do high-cost producers. The competitiveness and profitability of a coal mine is based on the costs of production and the supply position on the cost curve. There is no single method of cost estimation, and the available methods consider only one or a few variables, leaving out multiple variables that could significantly affect the estimation of mine costs. Mining companies are thus searching extensively for a method that will increase accuracy in the estimation and evaluation of mining projectsThis paper highlights the shortcomings of the available approaches and proposes a data envelopment analysis method to develop a frontier for effective surface coal mines, and the use of a parametric method for modelling the costs and productivity of new mines to ensure effective competitiveness. The models will extend the capability of estimation and the accuracy of estimates using the efficient decision-making units, by considering the optimal mine-specific and external variables affecting costs.IntroductionCoal contributes 25% of the world’s primary energy needs, after fuel oil, which contributes 35%. The world energy demand, estimated over the period 1990 to 2030, is expanding at a cumulative annual growth rate (CAGR) of 1.7% (Schernikau, 2010, p. 14). This emphasizes the need for enhancing the production of existing mines, as well as opening new mines in order to increase the supply of coal."

Jan 1, 2015

By K. S. Liddell

The Kell Process has been developed for the extraction of platinum group metals (PGMs) and base metals from sulphide flotation concentrates. The process has been successfully tested on several different sulphide flotation concentrates, including those from the UG2 chromitite horizon and the Platreef mafic/ultramafic layer. It has been shown to provide high (>95 per cent) and selective extraction efficiencies for the key valuable metals, i.e. Pt, Pd, Rh, Au, Ni, Co, and Cu. The Kell Process consists of several commercially proven unit operations. S, Ni, Co, and Cu are first selectively removed by use of a pressure oxidation step during which the dissolution of PGMs is minimized. The residue from pressure oxidation is subjected to a thermal treatment to ensure efficient PGM recovery by subsequent chlorination. All the core steps are very similar to well-proven conventional unit operations in common use, as are the subsequent metal recovery steps to provide marketable end products. Typical metallurgical responses of flotation concentrates from UG2 and Platreef to the Kell Process are provided, and key outcomes of an energy comparison study with smelting are summarized in this paper. Kell presents a potentially substantial improvement in PGM concentrate processing technology, in terms of economics via much-reduced power costs, ease of processing, and various environmental benefits. It allows for the treatment of high-chromium low-grade 'dirty' concentrates, such as secondary concentrates from the platinum industry's 'mill-float-mill-float' (MF2) flotation circuits and concentrates from retreatment of tailings. It allows greater concentrate mass pulls, has higher tolerance to gangue intergrowths in concentrates, and its use can provide substantial increases in overall PGM recovery. Its adoption would be a step change in the platinum industry, and given the commercially proven unit operations embodied in the Kell Process, at much-reduced risk compared with other more experimental technologies. Since the initial process development work, significant improvements and refinements have been introduced as a result of further compre¬hensive testing and process modelling. Pilot-scale testing and engineering study work is in progress for several selected sites.

Jan 1, 2012

By G. Akdogan, S. M. Bradshaw, A. P. Van Wyk

In the mineral processing industry, Ni-Cu-Fe-S converter matte is leached to remove base metals from a concentrate containing platinum group metals (PGMs). We investigated the atmospheric leaching process to develop a better understanding of the leaching behaviour of the base metals (Cu, Fe, and Ni) and the PGMs, in particular Ru, Ir, and Rh with respect to key process variables, acid concentration, and Cu concentration under oxidative and non-oxidative conditions. With oxidative leaching, a higher initial acid concentration resulted in higher Cu, Ni, and Fe extractions, as well as faster leaching reaction rates. A higher initial acid concentration also resulted in faster precipitation of Cu, Ru, and Ir under oxidizing conditions. Under non-oxidative conditions, Ni and Fe extraction was much slower, and the effect of initial acid concentration on Cu precipitation was less pronounced. The initial Cu concentration had a slightly smaller effect on the leaching behaviour of Fe and Ni, as well as precipitation of Ru, Ir and Rh. Moreover, a higher initial Cu concentration suppressed both Ni and Fe leaching and had a slight inhibiting effect on the precipitation behaviour of Cu, Ru, and Ir.

Nov 1, 2021

By J. Lehmann, H. Gaye

A brief review of Computational Thermodynamics software concerning the modeling and prediction of reactions involving metals, slags and fluxes is presented. Their application for various steelmaking treatments is discussed. Examples concern phosphorus removal in BOF and EAF, ladle steel desulfurization, and specific treatments for inclusions control in semi-killed or Al-killed carbon and stainless steels.

By H. Kotzé

Ticor SA began with a detailed feasibility study in 1995. The Hillendale mine (situated between Richards Bay and Empangeni) and mineral separation plant were approved in 2000. The smelter, just outside Empangeni, consists of two 36 MW DC arc furnaces that were commissioned in 2003. Experiences gained during the initial commissioning of the furnaces proved valuable in later commissioning work, as shown by the increase in ramp-up rates. The capacity of the plant is 250 kt/a TiO2slag and 145 kt/a of pig iron.

Jan 1, 2006

1. Book reviews Geophysical and geochemical techniques for exploration of hydrocarbons and minerals, edited by M. Sittig. (Reviewer: J. Keenan) Separation procedures in inorganic analysis. A practical handbook, by Roland S. Young. Charles Griffin, 1980. £23.00. (Reviewer: R. Murray-Smith) 2. Historical reprints Theinin~rs dictionary, by William Hooson. £14. Discovery of subterraneal treasure, by Gabriel Plattes. £12. Fodinae Regales (The Mines Royal), by Sir John Pettus. 3. De Beers' booklets Amborite - a remarkable new cutting material, by De Beers Industrial Diamond Division (P.O. Box 916, Johannesburg 2000). Booklet, 14 pp., free of charge. Natural and synthetic micron powders, by De Becrs Industrial Diamond Division (P.O. Box 916, Johannesburg 2000). Leaflet, 5 pp., free of charge. 4. New books Nickel in the environment, edited by J. O. Nriagu. New York, Wiley, 1980.928 pp. $65. Underwater minerals, by D. S. Cronan. London, Academic Press, 1980. 364 pp. $57.50. Data conversion integrated circuits, edited by D. Dooley. New York, Wiley, 1980.298 pp. $26.95 (cloth), $17.50 (paper). 5. NIM reports Report 2057 A mineralogical study of the Rooibokkop- Boschhoek copper deposit in the Marble Hall area. Report 2069 A utomatic setting of the distance between sample and detector in gamma-ray spectroscopy. Report 2070 The prereduction of chromites from the UG-2 Reef. Report 2075 The optimization of some of the conditions for analysis by spark-source mass spectrometry. Report 2082 A survey of the literature on gravity separation.

Jan 1, 1981

By C. Wade, A. Swart, M. Dworzanowski

AngloGold Ashanti operate a pyrite flotation plant at their East Gold Plant, Acid Plant and Flotation Plant (EGAF) metallurgical complex within their Vaal River operations in the North West province in South Africa. The flotation plant feed is reclaimed pyrite rich tailings and the concentrate produced is used as the source of sulphur for the EGAF acid plant. The sulphuric acid produced is in turn used for the recovery of uranium at the Vaal River South uranium plant. The original flotation plant built in 1960 was based on the use of many small volume flotation cells and was becoming very expensive to operate and its age severely limited further operation. A decision was taken in 2005 to replace this plant with a new one based on fewer, larger volume flotation cells. This paper describes the benefits of using larger volume flotation cells in this new flotation plant when compared to the smaller volume flotation cells in the old plant. The benefits of the new plant include a smaller plant footprint, fewer flotation cells, fewer pumps, no distribution boxes, simpler piping, a greater flotation volume and a reduction in installed power. The saving in capital cost could not be quantified because of the age of the old plant. The savings in operating cost will arise from fewer operators, less maintenance and reduced power consumption. The new plant has not been in operation long enough to quantify the benefits in operating cost and metallurgical performance. However, recovery improvements can be expected given the greater flotation volume (increased residence time) and the installation of larger, more efficient flotation cells.

Jan 1, 2007

By F. T. Cawood

Inauguration of the new political dispensation in South Africa in 1994 initiated a dynamic shift in the ownership, management and development of the country’s affluent mineral heritage. The process of substituting the old South African regime with a new equitable system, started soon after the 1994 election of the African National Congress (ANC) to parliament. The Congress’ Freedom Charter revealed the intent of the new dispensation when it called for radical transformation of mineral development. However, since 1955 there have been important changes affecting the rules of mineral development. These are: •Firstly, a drastic change in politics ushered in by negotiation, a spirit of reconciliation and a desire to settle disputes peacefully •Secondly, the globalization of the South African mining industry in tandem with the opening of domestic mineral resources to foreign capitalists; and •Thirdly, the introduction of sustainable development as a holistic approach to mineral development in order to replace traditional narrow-minded environmental management. Each of these significantly shaped the new mineral investment environment of South Africa. This paper represents a summary of the historical developments leading to the current Mineral and Petroleum Resources Development Act No. 28 of 2002, its Regulations, the much-publicised Broad-Based Socio-Economic Empowerment Charter and its associated Scorecard.

Jan 1, 2003

By R. P. Singh

A mine fire model gallery has been designed and constructed on the premises of the Central Mining Research Institute, Dhanbad, India to perform systematic in-depth studies on various aspects of mine fires. The gallery is 65.5 m long and 5.86 m2in cross-section and it is divided into firing and non-firing zones. It is equipped with a computer-aided online telemonitoring system that has 130 sensors, two data loggers and computer peripherals for continuous recording of various fire parameters. A fan to generate airflow through the gallery has been installed at its end. Two sliding doors and one rolling shutter were also provided for sealing and regulation of airflow. Two sets of experiments have been carried out in the model gallery maintaining air velocity of 1 and 1.5 m/s through it. In the experiments, the inner sides of the firing zone, 22 m in length, were lined with a thin layer (8?10 cm thick) of coal slabs. Two fire suppression techniques viz. flushing of liquid nitrogen (LN2) and infusion of high pressure high stability (HPHS) nitrogen foam were tried to quantify their effectiveness under dynamic fire conditions. The paper addresses important design features of the gallery, its instrumentation system, the experimental procedure adopted and important findings from the experiments. It has been observed that the intensity of the fire was very high after one hour of its initiation and continued for 3?4 hours. During the period, frequent backlash with smoke and flame was noticed. The efficacy of the fire suppression techniques has been assessed interms of reduction in temperature, generation rate of CO2and CO, and heat release rate. The study reveals that high pressure high stability (HPHS) nitrogen foam is more effective in controlling open fires than liquid nitrogen is. Keywords: Model gallery, telemonitoring system, velocity, temperature, pressure, gas concentration, intensity, liquid nitrogen, high pressure high stability nitrogen foam.

Jan 1, 2004

By C. N. Harman

Steel is the most versatile material which has made the progress in every aspect on this earth possible. There are hundreds of varieties of steel because for each application it has to be made with specific properties to get the most optimum usage. It is well known that the basic constituent of steel is iron. But it is the proportion of other elements in it, which give each type of steel certain specific properties. These elements are added in liquid iron inform of Ferro alloys to get the desired composition and properties. Thus, Ferro alloys are important additives in the production of steel. It can be said that no steel can be made without use of one or more of the several Ferro alloys. They form the backbone of steel. Thus, the Ferro alloys industry is vitally linked for its growth and development to that of the steel industry. Ferro alloys industry in India has never been globally competitive, despite its rich ore deposits and low-cost manpower, essentially due to a) Insufficient availability and high cost of electric power b) Increasing ores and reductants cost c) Non-availability of low ash, low phos. coking coal in the country for the production of desired coke with low ash, and low phos. contents, making import of such coke at a high cost imperative d) High-cost and insufficient infrastructural facilities (both road and rail) for rapid transportation of ore from mines to plants e)Stiff competition from producers and exporters of Ferro alloys in other countries like South Africa, Kazakhstan, China, Russia, Australia etc. due to global trade agreement which has made drastic reduction in customs duty on imports necessary. f) Wide fluctuations in the International price of Ferro alloys depending on demand versus supply. To over come these challenges plus adhering to stringent pollution control norms innovations are inevitable in the process technology, and plant equipment design, along with frequent changes in product mix, to be more cost-effective. An attempt is made in this paper to address the innovations that took place in the past and those that further need to be made, considering the future of this industry.

Jan 1, 2007

By B. S. Xakalashe, I. J. Geldenhuys, M. W. Erwee, Q. G. Reynolds, R. T. Jones, S. P. Tsebe

Aspects of the production of platinum group metals by reductive smelting in direct-current arc furnace processes are investigated using a computational modelling approach. The replacement of fossil carbon as a reductant by alternative reductants such as silicon carbide, ferrosilicon, and hydrogen is desirable for reducing direct greenhouse gas emissions from such processes, but the impact of these changes on the electrical operability of the process is poorly understood. This paper presents a study of plasma arc behaviour in the context of the ConRoast® reductive smelting process for Upper Group 2 ore as well as processes for recycling of automotive catalysts, using an integrated computational modelling workflow. It was found that the freeboard gas compositions, plasma properties, and arc behaviour were all affected by the choice of reductant, particularly in carbon-free smelting using ferrosilicon or hydrogen.

Mar 6, 2026

By R. E. Wilmot

The problem of corrosion of reinforcement in concrete structures is internationally recognized and represents the single biggest expenditure in the preservation of steel reinforced concrete structures. While the corrosion protection of the reinforcing steel is no substitute for design and the placement of good quality concrete, it does provide for a viable and economical extension of structural integrity and service life in the day-to-day and practical environment in which concrete structures are constructed. The mechanism of corrosion attack and consequent deterioration of reinforced concrete structures is well understood and documented. New structures can be designed and built to withstand corrosion. However, due to short-term economic restraints, many new reinforced concrete structures continue to suffer as a result of corrosion damage, which results from the corrosion of the steel reinforcing. This paper explores the economic and practical benefits offered by the application of hot dip galvanizing as a viable means of protecting reinforcing steel concrete structures. The paper also discusses technical misconceptions that exist about application and performance provided by the use of hot dip galvanized reinforcing steel.

Jan 1, 2007

By M. G. Maruma

The effect of the amount of cold reduction and annealing temperature on the evolution of the texture of AISI 441 steel is reported. The steel was cold rolled by 62%, 78%, and 82%, followed by isothermal annealing of each sample at 900°C, 950°C, and 1025°C for 3 minutes. The crystallographic texture was determined by Phillips X?Pert PROMPD texture diffractrometer. Microstructures were characterized using optical microscopy and scanning electron microscopy (SEM).The results show that sample that received 78% cold reduction and annealing at 1025°C presented the highest Rm-value and lowest ?R-value, which would enhance its deep-drawing capability. In addition, this sample showed the highest intensity of shifted ?-fibre, notably {554}<225> and {334}<483>. It can therefore be concluded that the ?-fibre, which favours deep drawing, is optimal after 78% cold reduction and annealing at 1025°C.

Jan 1, 2013

By A. C. Moorgas, J. Divall

This study investigates the feasibility of using waste iron slag, the by-product from a mineral sands processing works, in road construction. The study includes the different options investigated for the treatment of a leachate that is produced during the cooling of the iron slag, prior to processing. It also reviews the reasons for choosing the current treatment option that is being trialed. Cooling the iron slag with water results in the formation of a leachate with a high pH and high sulphide concentration. This leachate can seep into the ground and, over time, it will contaminate the ground water. A system was designed to collect and treat the leachate to prevent contamination of surrounding natural water sources. Numerous leachate treatment options were investigated to find cost effective method of treatment After cooling, the iron slag is passed through an iron recovery plant and the unsaleable product is placed on a dumpsite. Rain percolates through the dumpsite, which can result in the formation of a leachate that can contribute to a contaminated plume. After extensive testwork, it was found that the dumpsite, which was leached of contaminants, could be screened and used as a G5material (specifications in Table II) in road construction. The initial challenge was to establish that this material was environmentally safe for use in this particular application. Approval from the Department of Water Affairs (DWAF) was required for the testwork and then for the long-term use of this material in the construction industry. The following challenge involved establishing a market for the material. Construction companies in the area were reluctant to change to a new product that was not naturally occurring. The economics of this project are extremely sensitive to transport costs and hence only projects within a specified radius can be supplied with the Black Top Gravel (BTG). This project is not are venue generator, but it does save the money that would be required to manage the dump, and it reduces the closure costs.

Jan 1, 2003

By F. S. Hoseinian, D. Deglon, L. leal Filho, M. Safari, T. C. Souza Pinto

This paper investigates the effect of chemical and physical operational parameters on the reverse flotation of Timbopeba itabirite iron ore in a pilot-scale pneumatic flotation cell. Operational parameters include collector and depressant dosages, feed rate, superficial gas velocity and solids concentration. Results show that increasing collector dosage results in an increase in quartz recovery, particularly for the coarser quartz where recovery increases by nearly 30%. Increasing depressant dosage results in a decrease in both quartz recovery and hematite loss, for the coarser hematite particles. Increasing the feed rate has no effect on quartz recovery or hematite loss, suggesting that the pneumatic flotation cell is not residence time constrained. Increasing the superficial gas velocity results in an increase in quartz recovery to an optimum at a Jg of around 0.6 cm/s after which it decreases significantly, particularly for the coarser particles where recovery decreases by as much as 50%. Decreasing the solids concentration does not affect quartz recovery but results in significant decreases in hematite loss. Here, fine and coarse hematite loss decreases from around 25% to 12% and 10% to 2% respectively. Superficial gas velocity and solids concentration are operating parameters which have the largest effect on the flotation performance of the pneumatic flotation cell. Results suggest that this flotation cell should be operated at relatively low superficial gas velocities and solids concentrations. However, these are pilot-scale findings and would need to be tested at an industrial-scale where different operating conditions may be optimal. Keywords: Operational parameters, reverse froth flotation; entrainment; iron ore

Jan 1, 2020

By M. Krasowska, W. Skinner, R. K. Asamoah

Understanding chemical interactions at solid-liquid interfaces have played a pivotal role in improving mineral flotation performance, increasing the rate of mineral crystallisation and profitable leaching of valued minerals and metals. This paper highlights gold leaching with links to surface and interfacial chemical processes occurring, and opportunities to maximise extraction while reducing usage of more recent scarce resources. From the review, there is a significant link between surface and interfacial processes and gold leaching performance. Evidently, gold leaching kinetics could be increased by changing leaching conditions, including manipulating the surface and interfacial interactions. Control of surface and interfaces during gold extraction could enhance rapid, smarter gold extraction and mitigate formation of passivation layers. Keywords: Surface and interfaces, refractory ores and concentrates, gold leaching, reaction mechanism and kinetics

Jan 1, 2020