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By P. Foster

Over the past decade there has been a great deal of research into the use of virtual reality (VR) and computer graphics in the mining industry. Much of this has led to developed applications including training simulators and accident reconstruction. One other area where there is considerable potential for virtual reality is that of mining ergonomics. This paper identifies those common ergonomic limitations associated with mining equipment that can be effectively modelled using VR techniques. From this, two simple models have been developed, namely (i) remote control continuous miner operation and (ii) free steered vehicle sight-lines, which demonstrate the practical use of VR in this area.

Jan 1, 2004

The extraction of minerals and coal at greater depth, employing higher-powered machinery to improve production levels, imposes an increased burden on the ability of a ventilation system to maintain an acceptable mine climate. Hence, mechanical mine cooling systems are often adopted, which can be expensive in terms of both their associated capital and operating costs. Consequently, in order to optimize the total mining costs, it is essential to provide the mine operator with a method with which to determine the most cost effective and efficient mine cooling system. In a previous paper1a novel energy analysis employing the concept of exergy was proposed and applied to cooling systems applied to two conceptual model mines, representative of UK deep coal operations, and their resultant subsurface thermal environ-mental conditions predicted. This paper presents an analysis of the results obtained from the application of this novel technique to assess the performance of various cooling systems applied to a current UK colliery that is experiencing climatic problems due to its depth and highly mechanized production and development workings. To perform this analysis, ventilation and climatic data collected at the case study mine were used to construct balanced mine ventilation and climatic network models to replicate the subsurface environment. Where air conditions exceeded specified climatic limits within identified climatically control zones, mechanical mine cooling systems were employed. A number of cooling system configurations were applied to these model to investigate the potential to satisfactorily regulate the thermal environment. The heat energy transferred out of the air stream by the various cooling methods was absorbed using a variety of chilled water systems, which were designed to operate at various water flow rates and temperatures. Models of various cooling system were developed and applied to control the underground climate within this mine network to within pre-set climatic limits. The results of a comparative analysis of the energy transfers that were produced by the application of the different cooling systems are presented in the form of exergy performance indices. The results produced by simulation models constructed to represent chilled water distribution networks to supply the various air coolers, are designed and balanced. The results of the exergy analyses applied to the operation of the various chilled water pipe networks are discussed and used to assess the exergetic performance of the application of each proposed cooling system to the mine ventilation network.

Jan 1, 2004

By F. Agterberg

In his 1978 monograph ‘Lognormal-de Wijsian Geostatistics for Ore Evaluation’, Professor Danie Krige emphasized the scale-independence of gold and uranium determinations in the Witwatersrand goldfields. It was later established in nonlinear process theory that the original model of de Wijs used by Krige was the earliest example of a multifractal generated by a multiplicative cascade process. Its end product is an assemblage of chemical element concentration values for blocks that are both lognormally distributed and spatially correlated. Variants of de Wijsian geostatistics had already been used by Professor Georges Matheron to explain Krige’s original formula for the relationship between the block variances as well as permanence of frequency distributions for element concentration in blocks of different sizes. Further extensions of this basic approach are concerned with modelling the three-parameter lognormal distribution, the ‘sampling error’, as well as the ‘nugget effect’ and ‘range’ in variogram modelling. This paper is mainly a review of recent multifractal theory, which throws new light on the original findings by Professor Krige on self-similarity of gold and uranium patterns at different scales for blocks of ore by (a) generalizing the original model of de Wijs to account for random cuts; (b) using an accelerated dispersion model to explain the appearance of a third parameter in the lognormal distribution of Witwatersrand gold determinations; and (c) considering that Krige’s sampling error is caused by shape differences between single ore sections and reef areas.

Jan 1, 2015

By E. C. de Beer

"SynopsisA number of important areas in nuclear fuel cycle, at both the front end and back end, offer ideal opportunities for the application of non-destructive evaluation techniques. These techniques do not only provide opportunities for non-invasive testing of e.g. irradiated materials, but also play an important role in the development of new materials in the nuclear sector. The advantage of penetrating radiation used as probe in the investigation and testing of nuclear materials makes X-ray and neutron radiography (2D) and tomography (3D) suitable for various applications in the total nuclear fuel cycle. The unique and different interaction modes of the two radiation probes with materials provide several opportunities. Their complementary nature and non-destructive character makes them most suitable for nuclear material analyses, analytical method development, and the evaluation of the performance of existing nuclear material compositions. This article gives an overview of the X-ray and neutron radiography/tomography applications in the field of nuclear material testing, and highlights a few of the success stories. Several selected areas of application in the nuclear fuel cycle are discussed to illustrate the complementary nature of these techniques as applied to nuclear materials.IntroductionDuring the development of new materials for the nuclear industry, materials testing and characterization are of the outmost importance to maintain safety standards and reliability. No compromise on safety in the workplace in any area within the total nuclear fuel cycle can be tolerated, and therefore most in-situ material characterization and testing is conducted by certified and qualified personnel schooled in destructive and non-destructive testing (DT and NDT) methods. Certification and qualification in NDT can be obtained through many training centres in South Africa in accordance with European, American, and other international standards (SGS, n.d.; SAIW, n.d.; African NTD Centre, n.d.)."

Jan 1, 2015

By J. Dahner

Total milling cost is composed of energy, liner and grinding media costs. In primary high ball load milling, the grinding media play the biggest role in total milling cost. This cost can be drastically reduced by improving the impact condition inside the mill. The impact condition inside the mill is influenced by shell liner design (as well as feed end and discharge design) and the type of discharge. The improvement of the impact condition will result in a significant decrease in grinding media consumption. The softened impact condition allows for better alloy optimization, resulting in a further reduction in grinding media consumption. Optimized liner design can also improve energy consumption as less energy is wasted in the projection of the grinding media. Magotteaux utilizes tools to simulate and show the grinding media trajectories for shell and end liners. This paper will present some practical examples where the media and energy consumption can be or has been reduced by optimizing liner design. Keywords Comminution, grinding, liner design, grinding media wear.

Jan 1, 2011

By P. Roy

Smelting or converting of sulphide concentrates and mattes in a batch operation presents a challenge when directing the off- gas to a conventional acid plant. The Hindustan Zinc Ltd. (a division of the Vedanta Group of companies) Chanderia Lead Zinc smelter was presented with such a challenge that was met with the adoption of the Cansolv® SO2 Scrubbing System. The Ausmelt top submerged lance technology used at Hindustan Zinc generates a furnace gas stream that containsbetween 0.1 vol% and 12 vol% SO2 during the three stages of batch smelting. Cansolv® SO2 Scrubbing Technology captures the SO2 to ensure that treated flue gas exits the facility at a concentration below 100 ppmv SO2 and it releases SO2 in a controlled fashion, to more closely match the needs of the existing acid plant. The application of a regenerable scrubbing system to capture SO2 from a batch-operated furnace and convert it to acid in a conventional acid plant was a first of its kind in the world. This paper provides an update on the design and operation of the Hindustan Zinc SO2 recovery system and suggests two improvements to the basic flow sheet that optimize the cost of SO2 scrubbing further.

Jan 1, 2007

By P. Roy

Smelting or converting of sulphide concentrates and mattes in a batch operation presents a challenge when directing the off- gas to a conventional acid plant. The Hindustan Zinc Ltd. (a division of the Vedanta Group of companies) Chanderia Lead Zinc smelter was presented with such a challenge that was met with the adoption of the Cansolv® SO2 Scrubbing System. The Ausmelt top submerged lance technology used at Hindustan Zinc generates a furnace gas stream that contains between 0.1 vol% and 12 vol% SO2 during the three stages of batch smelting. Cansolv® SO2 Scrubbing Technology captures the SO2 to ensure that treated flue gas exits the facility at a concentration below 100 ppmv SO2 and it releases SO2 in a controlled fashion, to more closely match the needs of the existing acid plant. The application of a regenerable scrubbing system to capture SO2 from a batch-operated furnace and convert it to acid in a conventional acid plant was a first of its kind in the world. This paper provides an update on the design and operation of the Hindustan Zinc SO2 recovery system and suggests two improvements to the basic flow sheet that optimize the cost of SO2 scrubbing further.

Jan 1, 2007

By J. -H. Wu, S. Nishiyama, Y. Ohnishi

The behaviors and stress distributions of the inclined jointed rock masses with different dip angles obtained from DDA are compared to the results of laboratory tests. By calculating the block stress distributions, it is confirmed that DDA can reproduce the arching around the trap door when lowering the trap door. The shapes of arching change with the angles of inclined layers. In addition, the earth pressures acting on the trap door shows non-symmetrical distributions when the layers are not horizontal. The stress concentration occurs in one side of the rock masses close to the trap door. Furthermore, the surface settlements are also related to the inclined angle, and the loosening zone in rock masses can be different from Terzghi’s theory [1]. Since, simulations have good agreements with the laboratory test , it demonstrates the applicability of DDA to explain the mechanical behaviors of tunnel, such as arching phenomenon, non-symmetrical earth pressure distributions acting on the trap door, and the surface settlement profile in the jointed rock masses. Dans cet article est décrite l’étude numérique du perçage d’un tunnel dans un massif de couches rocheuses jointes inclinées. La simulation à l’aide de l’Analyse de Déformation Discontinue (DDA), en faisant varier l’angle d’inclinaison des couches de roche, nous apporte des résultats en termes de distributions de contraintes et de comportement des couches, résultats qui sont ensuite comparés avec des résultats de tests en laboratoire. Les résultats confirment le fait que la DDA est capable de reproduire le phénomène d’arcage autour de la trappe lorsque la trappe s’abaisse. Les formes d’arcage varient selon l’angle d’inclinaison des couches de roche. Par ailleurs, lorsque les couches ne sont pas horizontales, la distribution de pression agissant sur la trappe est assymmétrique. La concentration de contraintes se produit du coté proche de la trappe. De plus, les tassements de surface dépendent eux aussi de l’angle d’inclinaison. En conséquence, les résultats de simulation sont en accord avec les tests en laboratoire, ce qui prouve que la DDA permet d’expliquer des comportements mécaniques du tunnel tels que l’arcage, les distributions assymmétiques de pression du sol sur la trappe, ainsi que le profil du tassement de surface dans la masse de roches jointes. Dieser Beitrag beschreibt eine numerische Studie über Tunnel im geklüftetem Fels. Das Verhalten und die Druckverteilungen in den unterschiedlich geneigten und geklüfteten Felsenmassen wird mit Hilfe des Discontinuous Deformation Analysis Programms (DDA) simuliert, und mit Laborversuchen verglichen. Die Resultate bestätigen, dass DDA der Gewölbewirkung im „Trapdoor“ Experiment gut reproduzieren kann. Die Form des Gewölbes, ändert sich mit unterschiedlichen Neigungswinkeln der Schichten. Bei geneigten Schichten entstehen unsymmetrische Druckverteilungen. Auch die Oberflächenabsenkung ist von dem Neigungswinkel abhängig. Die gute Übereinstimmung der Simulationen mit den Laborversuchen zeigt, dass die DDA-Methode gut geeignet ist, um das mechanische Verhalten von Tunneln, wie z.B. den Effekt der Gewölbewirkung, die unsymmetrischen Druckverteilungen bei geneigten Schichten, oder die Oberflächenabsenkung in geklüfteten Felsenmassen, zu erklären.

Jan 1, 2003

By D. F. Malan

In deep level hard rock mining the rheological behaviour of the rock is important as time-dependent aseismic processes can lead to a stable dissipation of energy thus reducing violent outbursts. Underground closure measurements, observations of time-dependent fracture formation and siesmic data indicate that the rock in deep South African gold mines shows significant time-dependent behaviour. The objective of this work is to quantify the time-dependent rock behaviour for laboratory specimens and underground conditions. Laboratory experiments indicated that lava and quartzite specimens undergo measurable creep strain at stress magnitudes below the failure stress. Quartzite is however prone to more significant creep at lower stress levels. A viscoelastic analysis showed that laboratory creep results can not fully explain the behaviour observed underground. The in situ behaviour is governed mainly by the rheological behaviour of the fracture zone and the resulting time-dependent formation of new fractures. A viscoplastic discontinuity model implemented in a boundary element program is used to simulate this behaviour.

Jan 1, 1997

By L. I. Gonzalez de Vallejo

SRC rockmass classification have been applied to 25 tunnels in Spain and Italy, for which it was found that much heavier supports than those estimated by the RMR index were required. SRC and RMR indices and other relevant geomechanical data were obtained during the site investigation and construction stages. Data corresponding to in situ stress measurements, analysis of tectonic structures, and instability problems arising during construction were used to asses the state of stress. The relationship between tunnel section convergence and the SRC and RMR indices was also analysed. Support measurements based on SRC and RMR classification were compared with those actually used during construction. These analyses indicate that for most of the tunnels examined, supports estimated using the SRC were much closer to those actually installed than those predicted by the RMR index. Bei der Verwendung des SRC-Systems zur Klassifizierung des Gesteins als Baugrund für 25 Tunnel in Spanien und Italien wurde festgestellt, dass viel schwerere Abstützungen benötigt wurden, als wenn die Beurteilung anhand des RMR-Systems angefertigt würde. Die Klassifizierung anhand des SRC- und des RMR-Systems, sowohl als auch andere wichtige geomechanische Daten wurden während des Ablaufs der Erkundungen und der Bauausführung gewonnen. Die Resultate der Messungen der Spannungen vor Ort, die Analyse der tektonischen Struktur und die Stabilitätsprobleme während der Bauausführung wurden dazu verwendet, um den im Felsgrund vorherrschenden Spannungszustand zu definieren. Das Verhältnis der Messungen der Tunnelkonvergenz zu dem SRC- und RMR-Index wurde auch analysiert. Die durch das SRC- und RMR-System vorhergesagte Grösse der Abstützung wurde mit der Grösse der Abstützungen verglichen, die am Bau letztlich verwandt wurden. Diese Vergleiche zeigen, dass für die meisten der studierten Tunnel die Vorhersage der Abstützungen, die anhand des SRC-Systems angefertigt wurden, viel näher der wirklich verwendeten waren als die Vorhersage anhand des RMR-Systems. SRC rockmass la classification ont été appliqué à 25 tunnels en Espagne et l'Italie, pour laquelle il a été trouvé que des appuis beaucoup plus lourds que ceux évalués par l'index RMR ont été exigés. SRC et des index RMR et d'autres données geomechanical appropriées ont été obtenu pendant l'enquête de site et les étapes(scènes) de construction. Les données correspondant aux mesures de stress(d'accent) in situ, l'analyse de structures tectoniques et des problèmes d'instabilité surgissant pendant la construction ont été utilisées aux ânes(culs) l'état de stress(d'accent). Le rapport entre la convergence de section de tunnel et le SRC et les index RMR a été aussi analysé. Les mesures d'appui basées sur SRC et la classification RMR ont été comparées avec ceux en réalité utilisés pendant la construction. Ces analyses indiquent que pour la plupart des tunnels examinés, les appuis évalués utilisant le SRC étaient beaucoup plus proches de ceux en réalité installés que ceux prévus par l'index RMR.

Jan 1, 2003

By T. Saito, S. Murata

An original concept of JRC-diagram that can evaluate JRC and its size-effect by using a fractal model was proposed. In order to confirm the applicability of the JRC-diagram, first, JRC of the tensile fracture surfaces of a granite and a sandstone were evaluated by both the JRC-diagram and Barton's JRC-profiles, and then, it was compared with the JRC inversely calculated from the peak shear strength that is obtained from the shear test for each fracture using Barton's empirical equation. As a result, JRC evaluated by the JRC-profiles was much smaller than the inversely calculated JRC. On the other hand, it became clear that JRC evaluated by the JRC-diagram is almost the same with the inversely calculated JRC, if the size of interlocking is evaluated correctly. Therefore, for the JRC evaluation, it is thought that the JRC-diagram is more applicable than the JRC-profiles. Als ein neues Verfahren zur Bewertung des Rauheitsindexes JRC für die Bruchfläche von Felsenschichten anhand eines fraktalen Modells, wobei auch der Maßeffekt berücksichtigt wird, wird ein JRC-Diagramm vorgeschlagen. Um die Angemessenheit der Bewertung vom JRC mit diesem JRC-Diagramm festzustellen, wurden die JRC-Werte an einer Bruchfläche zwischen Granit und Sandstein sowohl mit dem JRC-Diagramm als auch mit dem herkömmlichen JRC-Profilverfahren bewertet. Anschließend wurden die durch die beiden Verfahren ermittelten Werten mit den JRC-Werten verglichen, die von den Schertestergebnissen mit Hilfe von Bartonschen Erfahrungsformel zurückgerechnet werden können. Daraus ergab sich, daß das JRC-Profilverfahren ziemlich kleinere JRC-Werte gibt als bei der Zurückrechnung, während die JRC-Werte durch das JRC-Diagramm unter entsprechender Bewertung des Ineinandergreifungsmaßes an der Bruchfläche beinahe gleich sind wie die zurückgerechneten Werte. Diese Tatsache weist darauf hin, daß das JRC-Diagramm eine bessere JRC-Bewertungsmethode als das JRC-Profilverfahren darstellt. Nous avons proposé le diagramme JRC, nouvelle méthode d'évaluer JRC qui est un indice de rugosité superficielle d'une fracture de roche à l'aide du modèle de fracturation, compte tenu de son effet d'échelle. Pour vérifier la validité de JRC évalué au moyen de ce diagramme, nous avons évalué JRC d'une fracture de roche, granite et grès, par le diagramme JRC et le profil JRC, méthode conventionnelle, et les résultats ainsi obtenus ont été comparés avec la valeur de JRC calculée en sens inverse à l'aide de la formule empirique Barton sur la base des résultats de l'essai de cisaillement des fractures. Il en résulte que la valeur de JRC obtenue par le profil JRC était assez faible en comparaison avec la valeur calculée en sens inverse alors que celle de JRC obtenue par le diagramme JRC correspondait approximativement à la valeur calculée en sens inverse à condition d'évaluer l'échelle d'endentement d'une fracture. Par conséquent, nous considérons que le diagramme JRC est une meilleure méthode d'évaluation de JRC par rapport au profil JRC.

Jan 1, 2003

By B Vorster

Falls of Ground is one of the highest causes of incidents, accidents and fatal injuries in our mines today. These falls of ground may occur as soon as the face is exposed after blasting or after machine cutting. The falls of ground can also occur after support has been installed. There are many reasons why these falls occur before and after supporting of the face. It is therefore important to support the exposed face as soon as possible to prevent the falls of ground. It is also very important to support the face with the correct support products and to support the face as designed and required by the mining engineers. The possible reasons for falls of ground, possible support methods and the products available will be discussed in this presentation. In typical conventional narrow vein stoping operations, the use of conventional temporary support components to offer some support to workers, whilst the permanent and generally more elaborate support system gets installed or constructed, still results in injuries to people. The author wishes to discuss the following items in this paper:- ? Introduction ? Basic face behaviour after exposure ? Controllable Parameters ? Mining Engineers support designs ? Primary and Secondary Support ? Products available for prevention of falls of ground

Jan 1, 2008

By J. -Y. Jia, G. -B. Qiu, C. -G. Bai, D. -F. Chen

Due to the great importance of the smelting process, it is essential to establish a calculation model on the viscosity of the slag system containing titania. In this paper, the calculation models of mass action concentrations and viscosity for the CaO-SiO2-TiO2slag system have been established according to the coexistence theory of the slag structure, as well as the referenced viscosities ofCaO-SiO2-TiO2at different temperatures and TiO2compositions. With the two models, corresponding calculated programs are made by means of programming language Matlab5.3, and the curves of viscosity of the TiO2concentration (?TiO2/%) at 1400°C, (R=0.9~1.0) are plotted. The results show that mass action concentrations of TiO2increases with increasing percentage ofTiO2, while the viscosity of CaO-SiO2-TiO2system is decreased. The results show that the models are in good agreement with the experimental and referenced data. They also shows that the models are reasonable for the CaO-SiO2-TiO2slag system. Keywords: coexistence theory; CaO-SiO2-TiO2slag system; viscosity ; calculation models.

Jan 1, 2004

By S. Ganguly, R. Kononov

Carbothermal reduction of manganese oxides and manganese ores in the solid state was studied in hydrogen, helium and argon at different temperatures, ore compositions and carbon to manganese oxide ratios. Wesselsore (South Africa) and two grades of the Groote Eylandt ore (Australia) with different level of impurities were examined. Ores were characterised by XRD, X-ray fluorescence, optical microscopy and scanning electronmicroscopy. Isothermal and temperature programmed carbothermal reduction experiments were conducted in a fixed bed reactor in a vertical tube furnace, with on-line monitoring of gas composition by the CO-CO2 infrared sensor. The reduced samples were characterised by XRD, SEM and LECO analyses. Extent of reduction was calculated using data on the off-gas composition, and LECO carbon and oxygen contents in the reduced sample. Manganese oxides in the ore were reduced to a-Mn and carbides Mn23C6 and Mn7C3 depending on the carbon to ore ratio. The reduction rate of manganese ores in hydrogen was higher than in helium and argon. Key words: Manganese, Carbothermal Reduction, Hydrogen, Argon, Carbon Monoxide, Helium, Kinetics.

Jan 1, 2007

Abstract : The computation of reliability index or failure probability of slopes can be transformed into an optimisation problem. In high rock slope engineering, it is usually a multimodal optimization problem. The traditional optimization techniques are difficulty to find out the global optimal solution because of their easily falling into local optimal value. Recently, a new kind of bionic algorithm - ant colony algorithm (ACA) - has been used to solve this problem. In this paper, the structure of ant colony algorithm and the transfer probability of ants are modified to evaluate the failure probability of complicated slopes. A new adaptive ant colony algorithm (AACA) is proposed to determine critical slip surface and its corresponding failure probability of complicated slopes. A case study is given to verify the proposed approach. The results show that the presented method has obvious advantages compared with traditional methods. ZUSAMMENFASSUNG: Die Rechnung des Zuverlaessigkeitindexes oder der Zerstoerungswahrscheinlichkeit kann sich in einer Optimierungsfrage umwandeln, im Bauprojekt an hoehe Gebirgehang, handelt es sich meistens um eine Optimierungsfrage ueber Multi- Spitzenwert. Mit der traditionelle Optimierungsmethode ist es schwer eine umfassende Loesung fuer die Optimierung zu finden wegen des leichte Verfallens in Beschraenkung der Teiloptimierungsloesung. Mit dem neue Bionik- Algorithmus —— Ameisen - Kolonie- Algorithmus wird dieses Problem geloest. In diesem Text hat man eine Strukturverbesserungsloesung fuer das Ameisen- Kolonie -system und die Wahrscheinlichkeit der Ameisenkolonie erwaehnt, und damit wird man die Zerstoerungswahrscheinlichkeit des komplizierte Hangs feststellen. Mit dem neuen Ameisen- Kolonie- Algorithmus kann man die gefaehrlichste Gleitflaeche und die entsprechende Zerstoerungswahrscheinlichkeit herausfinden. Die in diesem Text beschriebene Methode wurde durch Praxis geprueft. Durch die Pruefergebnisse wurde es gezeigt und bestaetigt, dass der neue Bionik- Algorithmus vorteilhafter als der traditionelle Algorithmus ist. Résumé : Le calcul de l’indice la fiabilité ou de la probabilité de ruptures peut être transformé en un problème de l’optimisation. Pour le cas du génie des pentes de haut rocher , le problème se pose en général en l’optimisation de multi-crêtes. Les techniques traditionnelles conduisent facilement à la solution optimal partielle au lieu de celle globale. Récemment un nouveau type de bionique algorithmique a été appliqué pour la solution de ce genre de problèmes, c’est l’Algorithme Colonie de Fourmis. Dans l’article il est proposé de modifier la structure du système de la colonie de fourmis et la probabilité de transfert des fourmis en vue d’évaluer la probabilité de ruptures des pentes de haut rocher complexes, par ailleurs un nouveau algorithme adapté de colonie de fourmis est formulé pour déterminer la surface glissante critique et la probabilité de ruptures correspondante. Les techniques proposées dans l’article sont vérifiées à travers des expérimentations dont les résultats ont prouvé que les techniques présentées dans l’article sont évidemment meilleures que celles traditionnelles.

Jan 1, 2003

By S. Kwon

When an underground excavation is created near to an instrumented measuring location, deformation at the location increases. The characteristics of this deformation increase, as well as the duration of the influence caused by the adjacent excavation, is dependent on parameters such as opening geometry and measuring location. In this study, neural networks were applied to investigate the deformation increase and the influence of each parameter on the deformation change derived from extensometer measurements at the Waste Isolation Pilot Plant (WIPP) site in New Mexico, USA.

Jan 1, 1998

In ilmenite smelting, the FeO content of the feed material (nominally FeO.TiO2) is decreased by reduction with carbon. In a parallel reaction, a significant amount of the TiO2 is reduced toTi2O3. One of the striking features of these reactions is a consistent relationship between the extents of FeO and TiO2 reduction; this relationship is independent of furnace size. It was recently proposed that this relationship follows from the solidification behaviour of the slag, where the final slag composition corresponds to the minimum melting point (?eutectic groove?) in the FeO-TiO2-Ti2O3 phase system; the hypothesis is that solidification equilibrium with the freeze lining stabilizes the slag composition. If this is the case, the system of slag and freeze lining must be capable of correcting two types of disturbances: thermal and compositional. Thermal disturbances result from incorrect power input, for the feed rates of ilmenite and reductant. For example, excessive power input will tend to overheat the slag, causing the freeze lining to melt partially, establishing a new steady-state heat loss from the furnace. Compositional disturbances result from an incorrect reductant input for the given power and ilmenite input. In this work, the dynamic response of the slag and freeze lining to different inputs (flow rates of ilmenite and reductant, and power input) is modelled. The model is based on solidification equilibria, and quantified heat loss through the freeze lining. The conclusion is that the solidification equilibrium cannot constrain the composition to the eutectic groove for typical operating conditions. Keywords: ilmenite smelting, freeze lining, solidification, high-titanium slag

Jan 1, 2004

By R. Dippenaar

Traditionally, iron ore has been reduced with coke in a blast furnace and the hot-metal product of the blast furnace containing carbon, manganese, silicon, sulphur and phosphorous, was subsequently refined in a steelmaking furnace. During iron making as well as during steelmaking, significant amounts of slag are produced. Two decades ago, more than 13 m tonne of blast furnace slag and 4 m tonne of steelmaking slag per annum were produced in the USA alone. It is, therefore, not surprising that many attempts have been made to re-use iron and steelmaking slags. However, these slags are not merely metallurgical waste products but, on the contrary, their compositions and physical properties are judiciously designed to optimize the operations in the respective metallurgical reactors. The variation in composition and properties of blast furnaces lags are largely determined by the gangue in the ore and ash in the coke and much progress has been made in the re-use of such slag. With respect to steelmaking slag, emphasis has in recent years been placed on hot-metal treatment before refining and ladle treatment after decarburization. The bulk removal of silicon, phosphorous and sulphur from the hot-metal product of the blast furnace by specially designed slags prior to refining in a basic oxygen furnace, has reduced tap-to-tap time, lowered cost and produced steel of much higher quality. The use of synthetic slags in ladle refining techniques subsequent to decarburization in the basic oxygen furnace has resulted in reduced hydrogen and nitrogen contents and reduced solute impurities. Moreover, inclusion shape and composition control, again by the use of specially designed slags has led to the achievement of much improved mechanical properties of the steel. In these revised process routes, slag of different compositions are produced in the variety of unit processes and hence the re-use of steelmaking slags has become much more complex. Clearly, a thorough understanding of the design and use of these different slags is a pre-requisite to the development of re-use strategies. Japanese steelmakers have spearheaded attempts to reduce slag volumes in the individual unit processes and to strive towards ‘slagless steelmaking’ by recycling slags internally. Steelmaking slag volumes have been reduced on commercial scale from about 140 kg/tonne steel to 60kg/tonne steel. Moreover, model predictions have shown that, in principle, all slag can be recycled and the phosphorous extracted to produce fertilizer. This development is of particular significance since the supply of low-phosphorous iron ores is diminishing at an ever increasing rate. Keywords: slag, environment, iron, steel,

Jan 1, 2004

By H. Zhu, F. Xu, T. Wang

Abstract : The deformation monitoring data of the middle pier of the in permanent ship lock in Three Gorges revealed several interesting deformation phenomena. Conclusions and explanations are made concerning the phenomena in this paper, based on the finite element and engineering geology analyses. Firstly, the fluctuation of the horizontal transformations can be attributed to the alternate excavation of the two neighbouring ship lock rooms. Secondly, the rock mass discontinuities result in the displacement breaks. Lastly, the main reasons for the one-sided leaning phenomena are the natural stress, which is not evenly distributed, and the presence of discontinuities. This paper presents a valuable reference for studying the ‘individual phenomena’ in geotechnical engineering. ZUSAMMENFASSUNG: Die Beobachtungs claten an der Mittelpier deformation bezüglich Permannenter Schiffsschleuse in den Drei Schluchten offenbaren einige interessante Deformationsphänomene. Die Schlußforgerungen und Erklärungen dazu in dieser Arbeit basseren methodisch anf der ‚’ ‘Endlichen-Elemente-Analzse’ und der ‘Ingenieurnissen-Geograhnie-Analzse’. Erstens kann die Fluktuation der horiyontalen Transformation durch die ungleichzeitige Ausgrabung der zwei benachbarten Schiffsschleusenräume verursacht werden. Zweitens resultzert die Diskontinuität der Felsenmasse ans dem verlagerten Bruch. Drittens: Die Hauptgründe für das Zu-einer-Seite-Neigung-Phänomen in manchen Stellen sind der ungleich eigeteilte natürliche Druck und das vorhandersein der Diskontinuität. Diese Arbeit präsentiert eine wertvolle Referenz für die Untersuchung der Sonderfälle in geotechnischen Bau. Résumé: Cet article a analysé sérieusement et profondément , en utilisant des procèdes d’étude par exemple l’analyse d’éléments défini et celle de la condition géographique de traveaux , des règles typiques de la déformation montrées dans les données surveillantes à propos de la déformation des pierres centrales dans les écluses éternelles du Trois Gorges , on en a tiré une conclusion : 1) le changement des chiffres des déplacements horizontaux des pierres centrales est causé par les creusages séquentiels des cannelure voisines ; 2) l’inclinaison au Nord de toutes les pierres centrales entre les deuxième et troisième chambres d’écluse est causée par la différence de la gravitation entre les deux chambres d’écluse et par l’existence de la surface structurale ; 3) l’existence de la surface structurale cause le changement des chiffres des déplacements horizontaux des pierres centrales au niveau profond . Cet article donne une référence utile pour l’étude du ‘ problème d’indivudualité’( ou les situations anormaux) dans les données surveillantes de la déformation des pierres centrales de la génie civile.

Jan 1, 2003

By F. Pinto, J. V. Lemos, A. Sousa, L. Ribeiro e Sousa

The Rossio railway tunnel was built in 1890 crossing several formations involving limestones, basalts and also sandy and clayey formations. Due to the fact that it is an old underground structure rehabilitation and repair works were performed, namely at Km 0,900 and in a zone crossed by a new tunnel from the Lisbon Metro. Reinforcement support systems were designed in the Rossio tunnel in order to prevent its stability. In this paper, repair works and anchor tests performed at km 0,900 are presented, as well as the monitoring system implemented in order to observe the structural effects induced by the construction of the works. For the interpretation of the obtained information complex 3D models was built, permitting the simulation of the sequential excavation scheme used, non-linear behaviour of the different formations, and the support systems used. Der 1890 erbaute Rossio Eisenbahntunnel durchoertert mehrere Formationen, einschliesslich einer Kalkstein-, Basalt- sowie einer sandigen und tonigen Formation. Auf Grund des Alters des unterirdischen Bauwerks wurden Instandsetzungs- und Reparaturarbeiten im Bereich km 0,900 sowie im Kreuzungsbereich mit einem neuen Tunnel der Lissabonner U-Bahn durchgeführt. Aussteifungssysteme wurden entworfen, um die Stabilität des Rossio Tunnels zu gewährleisten. Im Folgenden werden die Instandsetzungsarbeiten und Anker Tests im Bereich km 0,900 sowie das Messystem zur Ueberwachung der strukturellen Auswirkungen der Bauarbeiten dargestellt. Zur Interpretation der gewonnenen Informationen wurden komplexe 3D Modelle entwickelt, die eine Simulation des Bauablaufs und die Anwendung nichtlinearer Stoffgesetze fuer die verschiedenen Formationen und Aussteifungssysteme ermöglichten. Le Tunnel ferroviaire du Rossio a été construit en 1890, traversant des différents terrains comme des calcaires, des basaltes et aussi des formations limoneuses et sableuses. Dû à l’ancienneté de l’ouvrage, des travaux de réhabilitation et réparation ont été faits, nomment au km 0,900 et dans la zone traversée par le nouveau tunnel du Metro de Lisbonne. Des systèmes de support renforcé ont été conçus pour le Tunnel du Rossio de façon à rassurer sa stabilité. Dans ce papier, on présente les travaux de réparation et les essais d’ancrage réalisés au km 0,900, et aussi, le système d’auscultation mise au point pour l’observation des effets structuraux induits par les travaux. De façon à interpréter l’information résultant de l’observation, des modèles 3D complexes ont été utilisés, permettant la simulation de la méthode séquentielle de l’excavation, du comportement non - linéaire du terrain et, aussi les systèmes de support utilisés.

Jan 1, 2003