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By P. Chris Pistorius

"Use of coke in blast furnace ironmaking is the main origin of carbon dioxide emissions from integrated steelmaking. Use of pre-reduced iron feedstocks would reduce the coke rate and, if pre-reduction were carried out with natural gas, would decrease the overall carbon intensity of ironmaking. Blast furnace productivity would also increase, because the blast volume per unit of hot metal would decrease. This paper shows that these trends can be predicted quantitatively, by using a conceptually simple Rist-style blast furnace mass and energy balance, assuming furnace productivity to be limited by the tuyere gas flow rate. Such predictions would assist in optimizing the choice of the degree of reduction and relative amount of pre-reduced blast furnace feed.IntroductionSteelmaking is responsible for some 5% of world CO2 emissions, at a rate of approximately 1.9 tonnes of CO2 per tonne of cast steel [1]. In integrated steelmaking, the ultimate source of most of the CO2 emissions is coke, the indispensible (and expensive) fuel and reductant for blast furnaces. There are several research programs underway worldwide which seek to lower the carbon intensity of ironmaking; one of the largest is the European ULCOS program [2], in which the main proposed change to blast furnace ironmaking is to scrub CO2 from the furnace off-gas (for possible sequestration), recycling the remaining gas to the furnace. To limit the recycling nitrogen load, oxygen rather than air is used to combust coke.A conceptually simpler approach is to charge prereduced feed (direct-reduced iron) to the blast furnace. This approach has been used for some two decades at the AK Steel Middletown plant, where some 200 kg of direct-reduced iron (DRI) is charged per tonne of hot metal [3]. The Middletown blast furnace has exceptionally high productivity (rate of iron production relative to the furnace hearth area), simply because less coke is required per ton of hot metal if part of the feed is already metallic. Midrex [4] has provided some quantitative predictions of the implications of DRI use in the blast furnace, stating that for every 10% of Fe in the feedstock that is in metallic form, the fuel requirement decreases by 7% and the productivity increases by 8%."

Jan 1, 2012

By André Xavier, Edim Bahamonde

En las últimas décadas ha habido un aumento del otorgamiento de concesiones mineras por parte del Estado peruano; sin embargo, paralelamente se ha incrementado el número de conflictos sociales. Ante este panorama, es necesario promover la participación de las comunidades a través de la conformación de comités de monitoreo ambiental participativo, como una herramienta que fortalezca las relaciones de confianza entre las empresas mineras, las comunidades y el Estado, de manera que se genere progreso en la línea de los Objetivos de Desarrollo Sostenible. Este estudio presenta los casos de los comités de monitoreo ambiental participativo de Orcopampa (Arequipa), Juprog (Ancash) y Mallay (Lima), como referentes de buenas prácticas que aportan al mejoramiento de la prevención de conflictos socioambientales.

Sep 20, 2019

By André Xavier, Nancy Bahamonde

Este estudio de casos de los Comités de Monitoreo Ambiental Participativo (CMAP) de Juprog, Orcopampa y Mallay muestra la experiencia de trabajo en espacios de participación ciudadana destinados a atender la demanda de información y transparencia de las comunidades donde se desarrolla actividad minera. Se presentan aportes de buenas prácticas basadas en la vinculación de los comités con las entidades públicas encargadas de la mitigación de impactos, así como los desafíos que resta enfrentar: institucionalización, incorporación de políticas de género, capacitación permanente, formación continua de monitores, comunicación asertiva respecto de los resultados y registro de los mismos como una línea de base.

Aug 30, 2020

By Gladys Calenzani, Alexandra Almenara, Graciela Arrieta

Según estadísticas del Minem, la participación de la mujer en la industria minera peruana llega a solo un 5.4% del empleo total en minería. De este porcentaje, casi la mitad corresponde a un cargo administrativo y solo un 4%, a un cargo de toma de decisiones. La presente investigación busca mostrar el diagnóstico inicial de participación de la mujer en la minería del Perú, estudiar el caso de Chile —país de la región cuya actividad principal también es la minería y que a la fecha tiene un 8.5% de participación de la mujer en la industria—, recoger aquellas buenas prácticas que podrían ser aplicables en el país y establecer los principales retos y propuestas innovadoras para la mediana y gran minería.

Sep 20, 2019

ABERDEEN, ESTHER, U. S. Geological Survey, Washington, D. C. ALLEN, VICTOR T., Director Geology Department, Institute of Technology, St. Louis University, St. Louis, Missouri. BATES, THOMAS F., Associate Professor of Mineralogy, Department of Earth Sciences, School of Mineral Industries, The Pennsylvania State College, State College, Pennsylvania. BOLGER, ROBERT C., Geologist, Pennsylvania Topographic and Geologic Survey, Harrisburg, Pennsylvania. BRIDGE, JOSIAH, U. S. Geological Survey, Washington, D. C. BURST, JOHN F., Geologist, Exploration and Production Research Division, Shell Oil Company, Houston, Texas. CAMPBELL, IAN, Executive Officer, Division of Geological Sciences, California Institute of Technology, Pasadena, California. FLINT, DELOS E., U. S. Geological Survey, Washington, D. C. FREDERICKSON, A. F., Associate Professor of Geology (Geochemistry), Washington University, St. Louis, Missouri. GLASS, HERBERT, Illinois State Geological Survey, Urbana, Illinois. GORDON, MACKENZIE JR., Geologist, U. S. Geological Survey, Washington, D. C. GRIM, RALPH E., Research Professor, Department of Geology, University of Illinois, Urbana, Illinois. HARDER, E. C., Aluminium Secretariat Limited, Montreal, Que., Canada.

Jan 1, 1952

By W. E. Horst

Historically, research organizations have made significant contributions to the development and commercialization of new chemical products for the mining industry and examples of commercial results are cited With the recent demise of research organizations within the mining industry and dynamic changes in the industry, the supporting role of R&D groups has become limited or non-existent. Cat- reduction requirements and new raw-material sources offer future opportunities for R&D organizations to continue their effective participation in the commerical development of new chemical products. Potential areas of interest for future process applications are reviewed.

Jan 1, 1986

By D. L. Johnston

"The avenues and degree of participation by aboriginals in the Canadian minerals industry have changed significantly during the thirty years of the author's career in that industry.The typical 1950s cycle of mineral industry involvement of a local non-Europeanized aboriginal was as an individual employee. The employment relationship would begin with the best of intentions by both parties of permanence and terminate when the pioneering employee was unable to reconcile the attendance behaviour required by the employer and the social-sharing behaviour demanded by family and friends.Cominco Ltd. has been a mine operator and developer in the North since the 1920s. Cominco's early experiences with employment of non-Europeanized natives at the Con Mine in Yellowknife, Northwest Territories from 1938 to 1986 was a negative experience from both the employee and employer ends. A series of classic failures in employment of individual aboriginals was a large part of the history. A few Metis or natives from other areas were the permanent aboriginal employees at Con (2010). Racial prejudice was overt on the street in Yellowknife and, it can be assumed, in the workplace, as well.The history of aboriginal employment at the Pine Point, Northwest Territories operation (1964 to 1988) was somewhat better but also frustrating. The mine was equidistant (80 km) from the Dene communities of the Hay River Indian Reserve and Fort Resolution, both on Great Slave Lake. Despite a large aboriginal presence and many well-intentioned efforts, employment of aboriginals at Pine Point never got much beyond ten per cent. These would have been half local and half northern prairie aboriginals. One continuing success story was the railcar loading and covering crew led by Ed McKay, a local aboriginal. This predominantly aboriginal crew did its own recruiting and several are on Cominco pension."

Jan 1, 1995

By K. Barr, F. Grenier, J. Hettinger

"To reach the Hemlo Gold Inc. objective of becoming the lowest cost, safest Canadian gold producer while causing no environmental damage, management embarked from its inception on a strategy to build an organization which would foster employee involvement wherever possible. This paper describes the organizational structure and how various innovative concepts have been implemented.BACKGROUNDThe Golden Giant Mine in the Hemlo area of North Western Ontario is owned by Hemlo Gold Mines Inc. 50.1% is controlled by Noranda. The mine commenced operations in March 1985 at a modest production rate. After it reaches full production by the end of 1988, with completion of underground development work, the mine is expected to operate at 3000 t/d and produce in excess of 300,000 ounces of gold per annum. This makes it one of the three largest producing gold mines in North America.Two other companies, Lac Minerals and Teck-Corona, operate mines on either side of the Golden Giant Mine. Noranda Geco Division is located 55 kilometers to the north at Manitouwadge. The majority of Hemlo Gold's 270 employees live in Manitouwadge where a mix of accommodation was constructed and made available for purchase by employees. Bus transportation is provided to and from the workplace with modern coaches. The housing and transportation policies were implemented prior to start-up and designed to help attract and maintain good employees.As shown in Figure 1, the operation is divided into five operating and support departments with each reflecting a high degree of departmental control and responsibility. For example, the mill department is responsible for all aspects directly relating to the milling complex including safety, operation, mechanical maintenance, assaying, instrumentation, and environmental control. Similarly, the mine department is responsible for all phases of operation, mine engineering, geology, and maintenance of underground mobile equipment. The plant department is responsible for maintenance of hoisting plants and conveyances, underground stationary equipment, all site electrical services, surface buildings, housing and yard maintenance. Efforts are made at every level of the organization, from departmental organization to individual job assignments, to ensure responsibilities are clear and that they encompass complete functions."

Jan 1, 1988

By Ken Musgrave

"What Most Effective Management Does?It must satisfy the demands, of three groups of people: owners, employees and the public.OwnersOwners want profitable operations that will pay them a return on their investment, plus operations managed for long life. Many owners are also concerned with employee's well being and their company's public image.EmployeesJob security and a good income are probably still the most important demands, however, as time goes by, employees are also demanding more involvement in safety issues, working conditions, and even how work is done.The PublicThe public requires acceptable environmental standards, as well as enjoying the prosperity supplied by a successful operation.How are Mines Managed?Most mines are managed very traditionally. The basic credo is that the managers make the decisions, and the hourly, and junior salaried employees do what they are told. Clearly this is the extreme case, epitomized by the long service shift boss who might say ""It took twenty-years to become a shift boss, and no miner is going to tell me what to do"" .There are some exceptions, two notable ones being Campbell-Chibougamau, and T.G.S. (now Kidd Creek Mines) which, in very different circumstances, decided on a more participative style.Campbell-Chibougamau, having closed down due to unprofitable operations, reopened, using a team structure with working leaders, and a system for sharing gains against cost targets with employees. Although the system has some problems, and development miners are bonused conventionally, this has been a basically successful program.Texasgulf Sulphur, a company with a history of non-union operations, and a participative management style, made a corporate decision to operate their Kidd Creek Mine in the same way. The orebody was rich enough to allow them the luxury to do this, but they have never had a strike, so perhaps they have more than saved the cost of the benefits and salaries they needed to pay. They also reward employees with a stock distribution scheme based on service and earnings."

Jan 1, 1985

By Hans Rumpf

INTRODUCTION Agglomeration is based on adhesion between particles. Production of agglomerates of specific strength, strain properties, size, porosity and structure necessitates the activation of the adhesive forces. To achieve this, it is important for us to know details of the various systems of adhesion. Reports on the work of our Institute for the investigation of systems of adhesion were published on various occasions. A reference to those publications is made in the following abstract, and the findings previously published are presented only to the extent necessary for a better understanding of more recent test results, or of changed ideas. 1. MECHANISMS OF ADHESION We must distinguish between various "mechanisms of adhesion". By "mechanism of adhesion" we understand the interaction between a particle and a substrate resulting from a clearly definable physical or physico-chemical process resulting in a definite mathematical interrelation- ship between the decisive variables.

Jan 1, 1977

By Adam Feiler, John Ralston

Optical reflectometry was used to study the attachment and subsequent detachment of silica particles (diameter 25 nm) from the surface of titanium dioxide wafers under well-defined hydro- dynamic conditions. Atomic force microscopy was used to measure the interaction between silica spheres (diameter 7 pm) and titanium dioxide wafers under the same solution conditions. In addition to repulsive electrical double layer forces, adsorbed polyphosphates provide a short-ranged steric layer that reduces the lateral interaction between the surfaces. The use of these two complementary techniques has given valuable insight into the process responsible for fine particle detachment and has particular application to surface cleaning.

Jan 1, 2003

By L. C. Lien

Tower crane layout (TCL) is a typical construction site layout (CSL) problem, which is suitable for a wide range of work assignments and site conditions. Tower crane is one of the key facilities for vertical and horizontal transportation of materials, especially for heavy prefabrication units such as steel beams, ready mixed concrete, prefabricated elements and large panel formwork such as machinery and equipment, and a wide variety of other building materials within a construction site. However, it is a difficult combinatorial optimization problem to determine the locations of tower cranes with materials quantity supply and demand for engineers. Swarm intelligence (SI) was very popular and widely used in many complex optimization problems which was collective behaviour of social systems such as honey bees (bee algorithm, BA) and birds (particle swarm optimization, PSO). This study applied a hybrid swarm algorithm namely particle bee algorithm (PBA) based on a particular intelligent behaviour of honey bee and bird swarms by integrates theirs advantages. This study compares the performance of PBA with BA and PSO for a proposed hypothetical construction engineering of TCL with materials quantity supply and demand problem. Results show that PBA performs better performance than the mentioned algorithms on a proposed hypothetical TCL problem.

Aug 1, 2013

By J. Yue

The particle breakage kinetics, product size and size distribution, as well as grinding limit for quartz suspensions in a horizontal stirred mill are investigated. Results of grinding studies on quartz suspensions in a horizontal stirred mill confirm "first-order" particle breakage rates. A comparison of equation fits reveal that the product size distribution from stirred mill is best represented by the Rosin-Rammler equation when compared to the Gaudin-Shuhmann equation, but results fit poorly as particle size below five microns. A method of determining breakage rates versus particle size is demonstrated which shows that the 10% top size fraction is most appropriate for the determination of specific breakage rates. The method is used to demonstrate the relationship between particle breakage rate and particle size. As the feed particle size becomes smaller, the size reduction ratio decreases and approaches a grinding limit which depends on the effective stresses created in the mill.

May 1, 2004

By M. D. Flavel

Research programs conducted by Allis-Chalmers Corporation are showing that the most efficient energy use in crushers is achieved when the forces applied to particles undergoing breakage are increased. Laboratory bench scale tests have been developed to confirm this phenomena, which was first observed in the field using HYDROCOME crushers with automatic setting controls. A new testing machine is described and methods of maximizing such benefits are postulated. FOREWORD Allis-Chalmers Corporation was founded in Milwaukee, Wisconsin, in 1847 as the E. P. Allis Company, which had an initial interest in manufacturing components in the grinding of flour. As such, its roots were started in reducing material size, which is covered by the generic term, comminution.

Jan 1, 1981

By Sunil K. Tripathy

Particle characteristics such as size, density, liberation and magnetic susceptibility play vital role in magnetic separation technique. To understand the performance of magnetic separation process for chromite beneficiation industry, particle characteristics need to be analysed. However, to date, this has been an expensive and time consuming task, thus only minimal amounts of this type of data are available in the literature. Several new methods are being developed, that will produce the required mineralogical and liberation data to provide processing information rapidly and inexpensively. Among these, QEMSCAN is a unique and advanced characterisation equipment used for liberation analysis for different ore whereas S.G. Franz Isodynamic Separator for determining the magnetic susceptibility. In Indian chromite deposits, the content of iron bearing minerals in the ore is typical which controls the Cr:Fe ratio in the product while treating in gravity based beneficiation plant. In the present investigation, detailed characterisation of two distinct chromite ore samples from Sukinda chromite deposit, India, was investigated which includes advanced mineral characterisation using QEMSCANand magnetic susceptibility measurement by using Frantz Isodynamic separator, etc.. Presence of haematite and gibbsite along with chromite mineral were identified as major gangue minerals in the high grade ore from XRD pattern whereas Goethite, Quartz, Haematite, Kaolinite, Ringwoodite identified in the low grade ore. The mass magnetic susceptibility of low grade ore is very high 5.2 cm3/g compared to 2.7 cm3/g for high grade ore, due to the presence of abundant quantity of iron bearing minerals. Subsequently, these two types of ore were subjected for magnetic separation for improving Cr:Fe ratio by using different magnetic separators viz. induced roll magnetic separator, wet high intensity magnetic separator, rare earth roll magnetic separator, rare earth drum magnetic separator. The results of magnetic separation studies indicated that, Cr: Fe ratio of the chromite ores can be improved to 3.99 and 1.97 from the feed assaying 3.09 and 1.29 respectively. Studies on rare earth roll magnetic separator indicated that both the ores were upgraded to a maximum Cr:Fe ratio level at optimised condition. Keywords: characterization, QEMSCAN, magnetic separation, rare earth roll magnetic separator, industrial mineral, chromite

Sep 1, 2012

By D. Lelinski, X. Nie, J. D. Miller, J. Hupka, K. Bukka

A preliminary characterization of soil components contaminated at a low level (7 nanocuries per gram) with toxic/radioactive metals has been carried out. Most radioactivity and metals content were present in the minus 100 mesh (<150 µm) size fractions. None of the size fractions examined qualified for uncontrolled disposal at dump sites, thus all material would have to be moved to discharge-controlled landfills. The metal content of the sample was below the limits for economical recovery, therefore eventual processing would be dictated by environmental concerns.

Jan 1, 1992

By G. Barbery

"Particle composition distribution is an essential feature of materials processed by physical separation methods. The amenability to segregate a feed material in a concentrate and a tailings stream depends to a large extent on what is called usually the ""liberation"" of the various mineral phases that are present in an ore. In fact the energy consumed in crushing and grinding has the major justification of producing particles that are as close as possible to monominerallic. Monophasic particles are able to reveal physical differences in mineral properties that make their separation possible. For many years, various authors have insisted on the concept of liberation, without noting that, in practice, it can be a pure concept which does not lead to measurements or predictions. The present paper insists on the concept of particle composition distribution, in which the complete distribution is the information to be obtained, and not the ""liberation·· of various phases, just like for particle size distribution, the complete distribution is an objective commonly desired, and not one or two values representing the coarse or fine fraction.2. NOTATIONS-EQUATIONSFor the purpose of the paper, a particle will be characterized by its volume Vp, and its volumetric composition with respect to a mineral of interest, which will be given the notation ""O"". All the other minerals present will be called ""1"". This notation does not imply that the particles are biphasic, but that we are interested in the composition of particles with respect to one phase only. The volumetric composition will be given the sybol m:"

Jan 1, 1986

By S. M. Bradshaw, E. Charikinya

"Microwave induced cracks have the potential to enhance metal recovery from coarse sphalerite particles in heap leaching operations by creating new crack surface areas for lixiviant and enhancing value mineral exposure. The mode of fracture and the extent of mineral exposure due to microwave induced cracks have not yet been investigated. The objective of this study was to determine the extent of particle damage and mineral exposure in microwave treated particles. This was done using X-ray computed tomography (XCT) and image analysis techniques. XCT analysis was conducted on small (–5+4.75 mm), medium (–16+9.5 mm), and large (–25+19 mm) sphalerite ore particles before and after microwave treatment (MT). Geometrical properties, such as volume and surface area of each mineral phase in each particle was determined from the XCT reconstructed images using VGStudioMax image analysis software. These geometrical properties were used to calculate the interfacial areas of sulphide mineral grains in microwave treated particles before and after MT. The ratio of specific interfacial area after MT to specific interfacial area before treatment was used as an indicator of the degree of preferential grain boundary fracture. The results showed significant grain boundary fracture after MT at all sizes. For small sized particles, about 31% of the interfacial area was lost compared to 23 and 16% for medium and large particles, respectively. The results also showed an increase in the degree of mineral grain exposure of 28, 26, and 15% for small, medium, and large particles, respectively, after MT. These results provide experimental evidence supporting improved mineral exposure due to MT. INTRODUCTIONFor some years it has been suggested that microwave treatment (MT) of ores might result in preferential grain boundary fracture that would have benefits such as improved grain exposure and particle weakening. (Kingman, 2006). Most of the experimental work investigating the application of microwaves to mineral processing flow sheets has focused on assessing the benefits of applying microwave technology to flow sheets consisting of size reduction and mechanical flotation cells (Kingman et al., 2004). Experimental studies have shown that coarse crushing during tertiary grinding of microwave treated ore resulted in a better liberated coarser flotation feed (Scott, Bradshaw, & Eksteen, 2008). It has been suggested that improved liberation in milled flotation feed, was due to the presence of grain boundary fracture in microwave treated particles. However, this improvement in coarse particle liberation does not necessarily translate to a significant improvement in downstream flotation recovery (Kobusheshe, 2010). This is as a result of the size limit to the flotation of coarse material, due to detachment forces acting on particle-bubble aggregates, which increase as the particle size increases (Jameson, 2012). Current conventional, mechanically agitated flotation cells are not designed to float coarse material (Jameson, 2012). Hence it has been difficult to show the downstream processing benefits of applying microwaves to ores processed by comminution followed by flotation (Kobusheshe, 2010). It is clear from investigations carried out so far that inappropriate downstream exploitation of microwave treated ore would fail to realise a meaningful process benefit (Kobusheshe, 2010; Ali & Bradshaw, 2011)."

Jan 1, 2016

By C. L. Lin

Previous research on particle damage during high pressure grinding roll (HPGR) crushing was limited by the resolution of point-projection micro CT systems and the extent of damage was described by the percent of particles cracked for different crushing methods as determined at a voxel resolution of 40 microns. With recent advances in X-ray optics, the resolution afforded with point-projection micro CT systems has been improved by at least an order of magnitude using a lens-based X-ray micro CT system. With the use of X-ray lens imaging the resolution is determined by the lens rather than by the spot size of the micro-focus X-ray source. The high resolution X-ray micro CT (HRXMT) system made by Xradia with a voxel resolution of less than 1 micron is now being used for the characterization of particle damage during HPGR crushing. In this way, the direct 3-D determination of the internal damage of crushed ore particles which vary from 40 mm down to 100 microns in size is being studied at a voxel resolution of a few microns. The number, size, and shape of cracks can now be measured at this improved resolution and for the first time the specific crack surface area distributions of the crushed product can be calculated from HRXMT images using specially designed software tools for 3D analysis. Results from selected crushing operations are presented. Copper ore particles from HPGR crushing at high pressure (6 N/mm2) are severely damaged having crack specific surface areas as great as 10 mm2/mm3. Keywords: HPGR, particle damage, X-ray micro tomography, crack surface area

Sep 1, 2012

By R Nicholson, N D. Cox, N W. A Lambert

"This paper reports on the long-term operation of a particle density meter (PDM) at the Bloomfield coal handling and preparation plant (CHPP). This unit has been operating continuously for over three years, providing real-time data to the operators to allow the monitoring of flotation circuit performance. PDM outputs include slurry density, solids concentration on both mass and volumetric basis, and particle density. Knowing the average particle density of a stream allows for the optimisation of the process in real-time.The calibration of the solids concentration measurement device proved very difficult as the factory calibration techniques and existing laboratory analysis did not give accurate or reliable results. The solids concentration device had to be re-engineered and a new calibration method developed that gave accurate and repeatable results. Independent verification of samples taken from the PDM was undertaken as part of the trial process.The operational reliability of the PDM was a major point of investigation. The initial installation of the unit revealed issues with large, misplaced material of up to 20 mm periodically entering the unit, leading to feed blockages. The presence of these misplaced, oversized particles in the flotation circuit was resolved by installing innovative automatic back flush systems on the PDM.From a plant perspective the PDM has been an invaluable instrument that has enabled irregularities in the flotation circuit performance to be identified, which sampling had not and could not readily identify. This was achieved by close monitoring of real-time tailings composition on a minute by minute basis over short and extended periods. Variations in the tailings stream with respect to particle density and solids concentration were traced back to other issues in the plant. In addition, the PDM has allowed cell optimisation with respect to reagent dose rate to be improved. The PDM with real-time feedback can negate the need for large sampling campaigns and analysis during plant optimisation programs.Citation:Lambert, N, Cox, N and Nicholson, R, 2016. Particle Density Meter, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 245&ndash;250 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016