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By T. Cutard, H. Marzagui, E. Ouedraogo, M. Roosefid, M. Prompt, C. Deteuf

The present work is achieved in the framework of a French national program on modeling and experimental characterization of the thermo-mechanical properties of refractory materials (PROMETHEREF). This research program is aimed to establish fair models and experimental database and to make it available to industrial partners for numerical simulation of industrial structures made of these materials. The present paper focuses on two silica-alumina refractory castables, an andalusite based one and a bauxite based one. We will present the first rheological characterization results achieved at room on normal and preheated samples of these two refractory castables. Refractory castables are characterized with the help of four points bending tests, compression tests and tensile tests.

Jan 1, 2004

By C. Vasquez, A. Nieto

In past drilling programs for a multi-seam Texas lignite reserve, extensive e-log data was collected; however, little laboratory analyses were performed. As a cost and time saving incentive, sampling of lignite was intensified. In a recent drilling program in east-central Texas, detailed laboratory analyses and e-log information was gathered on a multi-seam lignite reserve of the upper Wilcox Group. This data will undergo statistical and geostatistical techniques in an attempt to discern whether or not predicted Ash and Btu/lb values can be derived from the e-log gamma-density relationships. Final characterization of the dataset will be used in a geostatistical model of that reserve. This model will be the basis for further geological investigations and mine planning.

Jan 1, 2004

Leaving the relatively simple life on a uni student and venturing off in to the outside working world is a big step. There are two paths to follow, the æContikiÆ style graduate program where you pick up your new lease vehicle and set forth on two to three years of planned activities, or can pack everything into one bag, stick a copy of æthe rough guideÆ in your pocket, and set off on your own graduate adventure. I took the path less travelled.The less followed method of developing yourself isnÆt for everybody. Parts of the journey are difficult and sometimes it feels hopeless, but itÆs all a learning experience. Along the way you might not get to all the graduate ætourist stopsÆ like dragline, truck-shovel, or drill and blast. But youÆll see most of them and pick up a lot more of the local culture such as people management, operational knowledge, quality control, and the black arts of project financial management.

Jan 1, 2004

By Roberto Parreiras Tavares, Frederico da Costa Fernandes, Guilherme Antonio Defendi, Vangleik Ferreira da Cruz, Júlio César de Sousa Pena

"Near-net-shape casting is an important area of research in the iron and steel industry today. Among the near-net-shape casting processes, the single-belt caster seems to be the most promising, since it is the only one that can achieve levels of productivity similar to those obtained with conventional continuous casting machines. One of the most important aspects in the single-belt casting is the feeding system used to deliver liquid metal over the belt. This system determines the velocity distribution and the levels of turbulence of the liquid metal and affects the quality of the strips. In the present work, a metal delivery system having a simple geometry was proposed. Using the CFD code CFX 5.6, a mathematical model to simulate three-dimensional turbulent fluid flow and heat transfer in that system has been developed. This model was used to analyze different configurations of the metal delivery system and the free surface shape of the fluid was also determined. A physical model of the feeding system was built and used to validate the predictions of the mathematical model. The fluid flow calculations have been validated by dye injection experiments and laser doppler anemometry. Measurements of the free surface levels have also been performed. These experiments provided supporting evidence for the predictions of the mathematical model.IntroductionTo maintain its competitiveness in the present market, the metallurgical sector, particularly the steelmaking companies, are developing new techniques of production. Some of these new processes are focussed on the strip casting technologies. Among these technologies, the SingleBelt process is considered the most interesting option, reducing the number of rolling steps and, consequently, the final cost of the product, especially the part associated to the energy consumption (fuel and/or electric energy). This process can also reach levels of productivity that can not be matched by other strip casting methods(1). One of the most important aspects concerning these new processes is related to the liquid metal delivery system. This system can have a significant effect on the final quality of the strips, since it determines the velocity distribution and the levels of turbulence of the liquid metal."

Jan 1, 2004

By G. C. Weatherly, D. S. Wilkinson, A. M. Limarga

In addition to the harsh environment, materials for high-temperature applications are often subjected to a significant mechanical loading. Several researchers have noted that the rate of oxidation can be affected by stress in a range of materials. We have recently studied this effect in y-TiAl, based on the preliminary work of Magnan and Weatherly which showed that nitridation rates on the tensile side of a flexural creep specimen could be 10 times higher than on the compressive side. We have since developed a four-point bending creep setup capable of controlled atmosphere testing. We present quantitative data on the effect of creep on scale growth under a range of atmospheric conditions. Finite element analysis will also be used to show how modest applied stresses can have a large effect on scale growth rates through the generation of large stresses due to the mismatch of creep rate between the metallic substrate and the scale.

Jan 1, 2004

By Z. Zhang, R. G. Reddy

Experimental and thermodynamic modelling studies on the structure of alkali borate melts and properties are discussed. A thermodynamic structure model for alkali borate melts is developed to describe the distribution of structural groups in the alkali borate melts as a function of composition. A qualitative interpretation for the boron anomaly in viscosity has been proposed, which regards the boron anomaly as a manifestation of the various antithetical effects caused by the introduction of alkali oxide into boric oxide. It has been found that the viscosity of alkali borate melts increases or decreases according to the changes in rigidity and spatial connectivity of the glass network structure, which is the function of temperature and composition. These concepts with some key examples are discussed in relation to their usefulness and practicality in industrial slags. Keywords: alkali borate melts; structural model; activities; structural groups; viscosity;

Jan 1, 2004

By Hans de Ruiter

"Delft University of Technology, RWTH Aachen, Helsinki University of Technology and Imperial College established the Federation of European Mineral Programs (FEMP) in 1999 as a legal body to coordinate joint M.Sc. education.By 2003 the number of participating universities in Europe has grown to 9 (in 7 countries) offering 3 different M.Sc. joint programs. Furthermore students from 8 universities in the USA, Canada, Australia and Chile participate through exchange agreements. About 25 companies are associated with FEMP. Further expansion with other clusters of universities is being investigated.So far some 160 students have taken the programs and are working in all parts of the world in a variety of jobs.The European Commission has recently announced the new “Erasmus World” program that will stimulate the offering of joint programs by European universities and offer third-country students and teachers a greater opportunity for mobility and an enhanced European added value. Host European postgraduate courses will be selected for a five-year period. They will receive funding from the Community and a “EU” seal. Around 250 “EU Masters Courses” will be established.The envisaged new Erasmus program and it’s network and operating practices are very similar to those being used by EMC, EMEC and EGEC. Erasmus World therefore offers a great opportunity for further developments with FEMP as the official body.INTRODUCTIONThe current situation in Europe is that globalisation of the supply of mineral resources has caused the larger mining and the manufacturing companies to expand and invest particularly outside Europe. However these industries still have a great significance for the European Union and its members, which means that mineral engineering know-how is still important in the E.U. It was therefore realised in the mid-nineties that is vital to maintain the very high level of knowledge and skill base in mining engineering and mineral technology that currently exists in the E.U., through good and well-balanced education programs."

Jan 1, 2004

By D. Xie, S. Sun

An overview of recent development of CSIRO?s Multi-Phase reaction models will be presented with examples comparing the calculated physico-chemical properties of metallurgical slags with the existing experimental data. The paper will also outline the development of a kinetically based model for molten bath reactors and its application to submerged combustion of coal in a slag bath as well as the reaction between the slag and injected coal particles. The plume model combines established models for the combustion of pulverized fuel with models for the growth and rise of bubbles from a lance or tuyere. This model predicts the extent of de-volatilization and combustion of the coal in the plume, the utilization of oxygen and the exchange rate of oxygen between the gas and the bath as well as the heat transfer rate between the gas bubbles and the bath. The slag reduction model brings together the recently measured rate data and fundamental understanding of the kinetics of CO-CO2reaction with iron oxide containing slags and predicts the changes resulting from injection of coal particles into molten slags. The top-space model covers reactions between gases and molten droplets in the post-combustion zone, where heat and mass transfer between phases results in higher utilization of the fuel values in the partly oxidized gases and transfer of heat to the molten bath. Keywords: Phase equilibria, viscosity, electrical conductivity, slags, kinetics, reaction rate.

Jan 1, 2004

By D. Satish Kumar, D. Mazumdar

"95% bulk mixing times in three different size water model ladles of a 140 T cylindrical shaped , dual plug ( located diametrically opposite at mid bath radius position) stirred, industrial ladle were determined experimentally with and without an upper buoyant phase. Based on dimensional analysis and a regression of the experimental data and, it was shown that in the inertial and gravitational force dominated flow regimes, 95% bulk mixing times for a slag-less situation can be described via:[equation]Parallel to this, a large number of experiments were also carried out in one of the water models (D=0.30m) to quantify the influence of an upper buoyant phase on mixing. These indicated that mixing time, operating variables and thermo-physical properties of the upper phase liquid can be correlated via a dimensionless relationship of the type:[equation]in which, Q is the ambient gas flow rate, L is the depth of liquid , (AL) is the slag layer thickness and 6 and t are respectively the surface tension and viscosity of the upper phase fluid The dimensional analysis, regression of experimental data as well as the adequacy of the proposed correlations are discussed in the text."

Jan 1, 2004

Jan 1, 2004

By S. K. Mishra, R. L. Lytton, D. Sinn, D. Saylak

Calcium chloride is widely used for dust control on unpaved roadway surfaces, in base course stabilization, full depth reclamation and for total reconstruction of asphalt roads. Fly ash produced from coal-burning electric power plants have also been used in road construction. This paper examines the synergistic effect of calcium chloride and fly ash on compaction density and strength development of unpaved roadways. A mathematical model has been developed which provides excellent agreement with the experimental data. Based on these results, the potential of calcium chloride - fly ash treatments for typical mine road construction is discussed.

Jan 1, 2004

By F. H. Abd EL-Rahiem

A selective dispersion process is presented and the work carried out to find optimum process conditions to minimise the colouring material in ground calcium carbonate (GCC) is described. The feed material is the overflow product from a hydrocyclone which results from using a Denver Attritioning machine with semi-autogenous grinding for one hour and a 1:1 ore/water ratio. By using sodium silicate (SS), with pH 9 and pulp density 5%, the iron content (as colouring impurities) is decreased from 0.21% in the original concentrate to 0.12% in the final concentrate. The degree of whiteness reached is improved to 85% from 63% in the original material. However, by using hexametaphosphate (SHMP) at pH 10 at the same pulp density, the iron content decreased to about 0.073% and hence the whiteness degree increased to about 96%.

Jan 1, 2004

Wetherstones gold deposit is located just east of the township of Lawrence, in the Otago District of the South Island, New Zealand. The paper will describe aspects of the mining and exploration history of the Wetherstones gold field, current knowledge of the geology of the deposit, and speculate on possible outcomes of exploration in the modern era.   As at the famed Gabriels Gully situated nearby, most of the Wetherstones gold is/was contained in, or recycled into modern drainages from, the Blue Spur Conglomerate (æBSCÆ). The BSC is the basal member of a wedge of auriferous non-marine sediments of latest Cretaceous age which are tilted against the Tuapeka Fault Zone, a structure of regional dimensions. In particular mineralisation of elevated grade (which cannot yet be reliably estimated) appears to be concentrated in an elongate basement depression (ægutterÆ) of width around 100 m, variable thickness to a few metres, and axial length in excess of 500 m. The gutter plunges from the base of alluvial mining (where it has been partly exploited by underground methods) to depths of more than 100 m, beyond which it remains open and untested.   The prospects for a revival of mining at Wetherstones depend upon confirmation of what is here inferred to exist, and the discovery of additional gold. The economic prospects of the project however are enhanced by what is known or indicated of the geographic location, and anticipated geologic, mining and metallurgical characteristics of the mineralisation, and consequent anticipated environmental management issues.   The recognition of gold contained in pyrite in the BSC represents an upside to project economics which has never previously been evaluated. The Wetherstones Basin covers more than five square kilometres in areal extent. There is no modern exploration record of the majority of this area, leaving open the prospect of the discovery of additional gutters, and primary mineralisation in the underlying schist.   Australasia Gold Ltd has embarked on a program to reassess the potential resources of the Wetherstones gold mineralisation, and to evaluate the feasibility of mining.

Jan 1, 2004

By Debbie Marshall

Nickel and cobalt in lateritic ores can be extracted by either a hydrometallurgical or a pyrometallurgical route. The high-iron limonitic fraction of a deposit is best processed' hydrometallurgically while the magnesium-rich transitional and saprolitic fractions are more suited for pyrometallurgical processing. During hydrometallurgical processing, it may be attractive, for economic reasons, to blend the limonitic component with transitional and saprolitic ores, which contain higher nickel levels. However, blending increases the concentration of magnesium in the feed, leading to increased acid demands. The decision on how much ore to process then becomes an economic one. Ore samples with different magnesium contents were prepared for the leach test program by blending limonitic and transitional ores. The ore samples were slurried in seawater and tested in the Falconbridge Hydrometallurgical Pilot Plant. As expected, acid consumption increased with increasing magnesium content of the ore. For target extractions of 95% nickel and 92% cobalt, the required residual free acid concentration increased from 30 g/L at 1.7% magnesium to 50 g/L at 2.7% magnesium. When the magnesium content was raised to 3.8% and 4.6% in subsequent pilot plant testing, the final free acid requirements did not increase beyond what was observed at 2.7% magnesium. Thus, the cut-off ore composition to maximize nickel units and minimize acid requirements is between 1.7- 2.7% magnesium. Keywords: high pressure acid leaching, laterites, magnesium

Jan 1, 2004

By Tim O’Neil

Question: Looking forward, do we face a future in which energy markets, energy policy and energy conflicts threaten to preoccupy, if not dominate, our concerns over economic growth, national security and domestic tranquility? The answer is, we may indeed face such a future. Question: What oil resource is comparable in size to the reserves of Saudi Arabia and presents a tremendous opportunity? The answer, the oil sands in Alberta, Canada. Question: What is the largest mineral staking rush in North American history, still under way? It has so far led to the development of two large mines. The answer is the Point Lake diamond strike in Canada’s Northwest Territories. It led to the development of the Ekati and Diavik mines.

Jan 1, 2004

Looking back 25 years, the role of the drill and blast engineer in an Australian mine seemed relatively simple, with the primary focal points being scheduling of the drill rigs, oversize control, and budget control with respect to consumption of both explosives and drill consumables. The choice of explosive selection was relatively simple, though many mines were becoming involved in trials of slurry explosives, emulsion blends, and low density ANFO blends. Guidelines to assist the engineer towards specific fragmentation targets were scarce, environmental constraints were light, and computers were rarely found on the desks of any mining engineers. Wall control blasting was in its infancy, with the bulk of attention being given to appropriate slope design and little real attention given to factors such as explosive distribution, and optimum delay timing and sequencing. Quantitative measurement of blasting performance was rare. The science of blasting, for fragmentation control, wall control, and environmental impact control was about to be born, and was heralded in those years by intense efforts by the explosive manufacturers and a proliferation of research centres throughout the world. Since the early 1980s, the role of the Australian drill and blast engineer has gone through a major metamorphosis, and currently requires a greater depth of scientific understanding than any other specialisation within mining engineering.

Jan 1, 2004

By M D. Basuki Dwi Priyono

The Toguraci low sulfidation epithermal gold vein deposits are located 2 km WSW from the Gosowong mine and form part of the Gosowong Goldfield. The goldfield lies within a Neogene magmatic arc on Halmahera Island, North Maluku Province, East Indonesia. The terrain is moderate to steep, rainforested, and poorly outcropping. Exploration and mining operations are being carried out within the PT Nusa Halmahera Minerals Contract of Work (exploration tenement) jointly owned by Newcrest Mining Ltd (82.5 per cent, operator) and PT Aneka Tambang Tbk. (17.5 per cent). First pass exploration of the Gosowong area began late 1992 resulting in the discovery of weakly developed porphyry copper mineralisation (named Bora) at Toguraci in 1993. Early in the evaluation of this porphyry an overprinting epithermal Au/Ag mineralisation event was recognised, however exploration focus remained on the Bora porphyry deposit for some time. The discovery of the nearby Gosowong epithermal gold deposit and the exploration of other prospects in the area further diverted attention and funds from Toguraci. It was not until year 2000 that Toguraci was seriously reevaluated as part of a detailed appraisal of the epithermal gold potential within a 5 km radius of the Gosowong gold mine. A fly-camp based drilling campaign using man-portable rigs was undertaken between August 2000 and March 2002. All exploration at Toguraci was then stopped pending government approvals to mine. These were finally issued in May 2003 and immediately drilling restarted and pre-mine approvals (eg the environmental impact study) were sought and granted. The first Toguraci gold bar was poured in February 2004. Exploration at Toguraci and elsewhere in the Gosowong Goldfield continues today.

Jan 1, 2004

By Steve Kral

After years of cutbacks, closures and layoffs, the mining industry is beginning to expand again. Metals prices are up and so is investor interest and confidence in the industry. Gold prices began to slowly move up in January2003 and finally cracked the $12.86/g ($400/oz) mark in early December. Silver, too, is up, as is copper. So the mining industry is feeling good about itself again and many companies are expanding existing mines and developing new ones. One side benefit to mining’s improved outlook is that companies are beginning to send more of their employees to industry conferences. Such was the case at the109th Northwest Mining Association meeting in Spokane, WA. The meeting was held in early December and attracted 1,100 attendees and 84 exhibiting companies. That is up from 2002’s attendance of about 900 people and 65 exhibitors. The theme was “A Partnership into the Future.”

Jan 1, 2004

By B McIntosh

Sustainability in its simplest assessment has been defined as æmeeting the needs of the present without jeopardising the needs of future generationsÆ. For the mining industry alone, this statement could indeed be interpreted by the many cynics in our community as an oxymoron; as miningÆs very existence requires the extraction and consumption of finite resources. However for the future of industry as a whole, the integration of mining, minerals processing and manufacturing presents us with a unique opportunity to achieve sustainability through the continued supply of metals and materials for society, in a manner which can achieve positive social outcomes through a triple bottom line approach.The Kwinana Industrial Area has been Western AustraliaÆs premier heavy industrial precinct for more than 40 years and its prevailing level of prosperity will ensure it remains a significant contributor to the State economy through the 21st century.The Kwinana industries depend on each other for the production of essential raw materials vital to their manufacturing and refining process, an innovation that also has significant environmental benefits.Formed in 1991, the Kwinana Industries Council strives to foster positive interaction between member companies and with the local community.The aims are:to co-ordinate the activities of Kwinana industries on a range of common issues; provide effective liaison with the local community; promote a positive image of Kwinana industries; highlight contributions to the community by Kwinana industries; and work towards the long-term viability of the Kwinana Industrial Area. The Kwinana Industries Council facilities these aims by focusing on developing and employing leading edge technology, giving workplace health, safety and environment top priority, and taking a committed, responsible and pro-active approach to environmental protection, whilst forging a two-way partnership with the local community.The sustainability of industry is the key objective for the Kwinana Industries Council and through the involvement of the 13 member companies industry strives to:achieve efficient processing of resources to provide a range of goods and services needed by the community; achieve acceptable and decreasing level of environmental impact; provide jobs and income for our community; and engage co-operative projects that benefit the local communities, the State and Australia.

Jan 1, 2004

By H. Griesel

The overall supply of platinum is forecast to rise more than the demand, and market deficit will narrow somewhat, but is still substantial at about 480 000 ounces. Because of this deficit, the price of platinum is expected to remain high, not taking into account the impetus from funds and speculators. With this strong demand for platinum and the high price, platinum producers still need to initiate projects to not only sustain current production, but also expand output into the high demand. However, the rise in the platinum price does not entirely offset the drop in revenue due to the strong rand. Consequently, in the current economic environment, executives and managers are under extreme pressure to initiate only the highest yielding projects and implementing them successfully. During the initiation phase of a project, the cost of changing concepts is the least, and strategic project decisions are the most important. It is during this phase that the most value can be added to a project, therefore requiring inputs from highly skilled, creative and experienced people. This paper will discuss thought processes and paradigms during the initiation of projects that will assist project owners in the selection and initiation of successful and profitable projects. The project initiation process will also be discussed outlining selection models, risk analyses and funding considerations.

Jan 1, 2004