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By T. F. Cho, B .. O. You, K. S. Yoon, K. S. Won

Discontinuity Orientation Measurement (DOM) drilling system capable of retrieving the reference line-marked core log, which can be used for determining the relative positions and orientations of discontinuity planes along the borehole axis, has been developed. Accuracy of the borehole joints data measured from the reference-lined core and, eventually, the significance and applicability of DOM drilling system for site exploration are verified by comparing with the spatial characteristics of joints investigated by implementing borehole image-taking instruments in the same borehole. Enhancement of boring efficiency has been also confirmed by performing twin drilling operations, one with DOM drilling system and the other with a conventional drilling machine equipped with D-3 core barrel, on two neighbouring sites of 5 m apart. Ein DOM(Diskontinuitätsorientierungsmessung)-Bohrsystem, das durch Grundlinien markierte Bohrprobelog extrahieren kann und die relativen Lagen und die Orientierungen der sich im Bohrloch verbreitenden Flächen bestimmen kann, ist entwickelt worden. Die Wichtigkeit des DOM-Bohrsystems und dessen Anwendbarkeit auf die Erforschung auf dem Bohrplatz werden dadurch bewiesen, dass man die Genauigkeit der Daten der Bohrlochsspalte, die durch die die Grundlinie zeichnende Bohrprobe gemessen werden, mit dem räumlichen Eigenschaften der Spalte vergleicht, die durch die Bildaufnahme des gleichen Bohrlochs nachgeforscht werden. Un system de sondage, Discontinuity Orientation Measurement (DOM), capable de récupérer des carottes markés en une ligne de référence a été dévelopé. Il peux être utilisé pour déterminer les positions relatives et les orientations des plans de discontinuité le long de l’axe de trou de sonde. Leur signification et applicabilité pour une caractérisation de site est verifiée par une comparaison de la précision des données a propos des joints mesurés a partir des carottes markés et les carac-téristigues spatiales des joints enquêtés par le camera de sondage

Jan 1, 2003

By K. -J. Shou

A special three-dimensional boundary element method has been developed for the simulation of the development of fracture zone in rock mass. This approach comprises a boundary element method and a three-dimensional tessellation mesh generator. By using the tessellation generator, a set of pre-defined potential fractures is defined, and the fractures activate when the failure criterion is exceeded. This approach is justified by the reproduction of features observed in laboratory simulations of fracturing in blocks of rock subjected to compression. An attempt is then made to explain some of the attributes of fracture zone surrounding underground openings. Eine spezielle drei-Dimesionen Grenze Element Methode ist entwickelt zu simulieren die Entwicklung der Fraktur Zone in der Steinmasse. Diese Untersuchung benutzt eine Grenze Element Methode und ein drei-Dimensionen tessellation Masche Generator. Durch das Benutzen des Tessellation Generator, ein Satz der vor-bestimmt potentielle Fraktur ist festgelegt. Die Fraktur wird betaetigen, wenn das gescheiterte Kriterium ist uebersteigt und sind in dem Verscheiben-Abbrechen Element eingeschlossen. Diese Untersuchung ist von der Reproduktion der Fraktur justiert, die ins Labor beobachtet wird, um die Fraktur in der von der Kompression unterworfenen Steine zu simulieren. Ein Versuch ist gemacht, um einige Eigenschaften der Fraktur Zone um die untertageoeffnung zu erklaeren. Une méthode tridimensionelle spéciale de élément frontière a été dévélopée pour la simulation du dévélopment d’une zone fracturée dans la massive roche. Cette approche comprend une méthode de élément frontière et un générateur de maillage de la mosaïque tridimensionelle. En utilisant le générateur de mosaïque, une série des fractures potentielles predéfinies est définie avec d’une procédure de la triangulation de Delaunay. Les fractures activent lorsque le critère de rupture est dépassé et sont inclues dans les éléments du déplacement discontinuité. Cette approche est justifiée par la reproduction des caractéristiques observées dans le laboratoire, les simulations des blocs de roche fracturé et sujetés en compression. La tentative est alors fait pour expliquer quelques arttributs d’une zone fracturée alentours les ouvrages soustérrains.

Jan 1, 2003

By D. W. Horsfallt

The above paper gives a fair amount of information and is a useful addition to the literature on a subject of growing importance. I believe that more experimental results could have been given, together with more details of the modifications made to the plant that enabled it to operate with the success mentioned in the paper. One important omission is a definition of the word fines. As pointed out elsewhere!, this word is used very loosely.

Jan 1, 1980

By J. -P. Gisiger

On the basis of laboratory test results a comparison of various parameters (unconfined compressive strength, CERCHAR and LCPC abrasivity indexes, mineralogy) is presented and discussed in order to outline certain correlations between them. Samples cover a wide range of lithological types coming from various sites of tunnels. A partir de résultats d’essais de laboratoire, une comparaison de divers paramètres (résistance à la compression simple, indices d’abrasivité CERCHAR et LCPC, minéralogie) est présentée et discutée dans le but d’en tirer certaines corrélations. Les échantillons couvrent un large éventail de types lithologiques provenant de plusieurs sites de tunnels. Basierend auf Laborversuchen, werden verschiedene Gesteinseigenschaften (Druckfestigkeit, CERCHAR und LCPC Abrasionsindexe) präsentiert und Korrelationen aufgezeigt. Die untersuchten Proben verschiedenster Lithologien stammen aus mehreren Tunnelprojekten.

Jan 1, 2003

By P. Jordan

The practice of ilmenite smelting in electric arc furnaces has been researched and published over the last few decades. An issue that has not been addressed is the understanding of the properties of ilmenite smelting reductants, and linking these properties to the subsequent smelting behaviour in the furnace. The reduction mechanism of ilmenite smelting is not fully understood, but it is believed that the Boudouard reaction plays a role. This paper investigates the behaviour of a number of reductants when reacted with CO2 at different temperatures. Keywords Boudouard reaction, carbon reactivity, reductants, ilmenite smelting.

Jan 1, 2011

By G. Whittle

An important aspect of the project evaluation process is the achievement of a clear and quantitative understanding of the primary drivers influencing project value and risk. A business scenario-based approach is required to ensure that the project meets value and risk hurdles over the short, medium and longer term. Adopting an optimising approach can aid significantly in the development of a project concept into a business that is optimal and sustainable in the longer term. Through the application of case studies, based on work performed with various mining organisations during the last five years, this paper will demonstrate how project value and robustness can be optimised. Experience has demonstrated that applying this approach results in significant value improvements and risk reduction - primarily by application of a rigorous, fact-based analysis and optimisation process that rapidly increases management team understanding and insight of key driver of value and risk.

Jan 1, 2007

By S. Neilson, M. G. Demmer, K. McCarogher

The Phoenix Programme takes the Mining and Mineral Processing Industry into the Science Classroom In the early years of mining, methods were crude, simple, labour-intensive, and very slow. Human resourcefulness, however, created innovations (mechanization, and computerization), that resulted in faster development, greater tonnages of ore, more efficient separation, and a superior final product. This expansion occured an ever-increasing rate, and resulted in a booming mining industry and a growing economy.

Jan 1, 1989

By R. Thomas

A Honeywell TDC 2000 central process control system was installed at Rössing in 1984. The system controls the metallurgical operations from crushing to the finished product of uranium oxide and manufacture of sulphuric acid. The operation was previously controlled from nine separate local control rooms. The paper briefly reviews the design and commissioning of the control system on an operating plant and discusses the impact on manpower organisation and training needs. Development of the process control system during its first two years of operation is reviewed and a summary is given of the current status of computer control at Rössing. The impact of the new system on overall plant operation and performance efficiency is also briefly described. In conclusion, future developments of computer control and overall optimisation of metallurgical operations are reviewed.

Jan 1, 1987

By T. Orupold

This paper covers the commercial development of gravity separation of fine particles using a Lamella High Shear Rate REFLUX? Classifier (REFLUX? Classifier), focusing primarily on coal applications. The REFLUX? Classifier is a fluidized bed device that incorporates a system of closely spaced parallel inclined channels located above the fluidized bed. These channels make it possible to achieve a significant suppression of the effects of particle size, resulting in a highly effective separation on the basis of density. The improved gravity separation performance is shown to be remarkably high, with a significant reduction in the variation of separation density with particle size, and a significant reduction in the change in Ecart probable error (Ep) with size. The first full commercial-sized units of the REFLUX? Classifier were field-tested in late 2009 in coal applications. More recently, the technology has been applied in fine particle separation in minerals applications and there are a number of full-sized units operating in chrome applications in South Africa. Initially, pilot-scaled units (typically the RC?300) were trialled in iron ore, mineral sands, and manganese plants amongst other minerals, typically after other technologies failed to achieve the desired results. Currently a number of laboratories globally are carrying out more testing in minerals applications. More than 50 RC? units are now operating in coal and minerals applications. This paper introduces the REFLUX? Classifier technology, identifies commercial applications, and gives some commercial results.

Jan 1, 2014

By H. Sasao, Y. Obara, A. Hirata

In the upper part of the planned location of the portal of a highway tunnel, there was a steep rock cliff with several unstable rock blocks. It seemed that the risk of those rock blocks to fall was very high. The cut-out to stabilize the rock cliff was monitored with various measuring instruments to prevent the sudden fall of the rock blocks. This paper discusses the measurement of acoustic emission and interpretation of its result during excavation of the rock cliff. We calculated displacements by integrating the accelerogram twice in terms of time, and demonstrated that slight displacements can be calculated from the measured AEs. Dans la partie supérieure de l’emplacement prévu pour le portail d’un tunnel autoroutier, il y avait un escarpement rocheux raide avec plusieurs blocs rocheux instables. Le risque de chute de ces blocs semblait très élevé. Lors de la coupe pour stabiliser l’escarpement rocheux, le suivi a été effectué avec différents instruments de mesure pour éviter la chute brutale des blocs rocheux. Cette thèse présente les mesures d’émission acoustique (EA) et l’interprétation de leurs résultats pendant l’excavation de l’escarpement rocheux. Nous avons calculé des déplacements en intégrant l’accélérogramme deux fois par rapport au temps, et montré que de petits déplacements sont calculables à partir des EA mesurées. Im oberen Teil des geplanten Ortes des Stollenmundes eines Autobahntunnels gab es einen steilen Felsen mit mehreren instabilen Felsenblöcken. Die Gefahr schien sehr groß zu sein, dass diese Felsenblöcke einstürzen können. Beim Abbau um die Stabilisierung des Felsens wurde das Monitoring mit verschiedenen Messinstrumenten zusammengestellt, um den plötzlichen Verfall der Felsenblöcke zu verhindern. Das vorliegende Papier diskutiert die Akustische Emission und die Auslegung deren Ergebnisse während des Abbaus des Felsens. Wir berechneten die Verschiebungen durch zweimalige Integrierung der Accelerogrammen in Bezug auf die Zeit. Die dargestellten kleinen Verschiebungen können aus den gemessten akustischen Emissionen berechnet werden.

Jan 1, 2003

By B. Geelhoed

Gy's formula for the variance of the fundamental sampling error (FSE) is based on a model that assumes independent selections of particles. A generalization of this model, which can theoretically lead to more realistic representation of actual sampling processes, was, for the first time, experimentally verified by repeated sampling from a well-mixed batch consisting of particles of zirconium silicate of two different sizes. The predictions for the sampling variance made in Gy?s theory and in the more general model were compared with the experimentally observed sampling variance. During the experiment performed here, the variance prediction made in the theory of Gy ranges from 0.96 × 10?7(g2/g2) to 0.95 × 10?7(g2/g2), which is approximately a factor 60 lower than the experimentally observed variance (5.76 × 10?6(g2/g2)). The difference between the Gy prediction and the experimentally observed variance cannot be fully explained by the uncertainty in the experimentally obtained variance due to the finite number of degrees of freedom. Therefore, the difference is likely to be a significant effect. This shows that, under the experimental conditions, Gy?s formula for the variance of the FSE probably undervalues the sampling variance, unless an empirical correction factor for grouping and segregation is applied in the theory of Gy. The new theory resulted in a variance prediction of 6.00 × 10?6(g2/g2), which is much closer to the observed variance than the Gy prediction. This indicates that the generalization of Gy?s theory offers an outlook for providing a better variance prediction than the Gy predictor in the case of dependencies between particle selections. The results are discussed. Keywords: sampling, variance, parameter for the dependent selection of particles, Gy, experiment.

Jan 1, 2009

By B. J. Pieters

The paper describes the difficulties experienced with inferior coking coals as Iscor began using larger blast furnaces for the production of liquid iron. Research conducted at Iscor from 1977 to 1979 showed that benefits could be gained from the use of partially briqueted charges, and it was decided to install briqueting plants at the Vanderbijlpark and Newcastle Works. Details are given of the later plant, which was supplied by a consortium consisting of Voest Alpine, Didier Engineering, and Sumitomo Metal Industries. Sumitomo also supplied information on the optimization of coke quality along the lines of their Sumicoal System. The results have been a marked improvement in coke quality, much better blast-furnace operation, and increased productivity.

Jan 1, 1991

By C. M. Sellars, W. E. Stumpf

SYNOPSIS The effects of concurrent recovery, prior creep deformation and concurrent high temperature fatigue on the coarsening of some carbides in steels have been studied. It was found that concurrent recovery enhances the coarsening rate by orders of magnitude and prior creep deformation causes an enhancement of about two times. Finally, concurrent fatigue causes an initial greatly enhanced coarsening rate but after prolonged cycling dissolution of the carbides occurs.

By J. B. A. Solar Menéndez, M. A. Martínez Fidalgo, L. A. Alvarez-Santullano

1. ANTECEDENTS This present communication refers to the results of the research project entitled "Training in the correct use of chemical oxygen self rescue apparatus and also an analysis of apparatus autonomy", carried out under the auspices of the Specific Collaboration Agreement signed between the Industry Council of the Principality of Asturias (Spain) and INSALUD (National Silicosis Institute, Spain). The antecedents of this project lie in work undertaken by the National Silicosis Institute aimed at optimising efficiency in the use of chemical oxygen self rescuers through improvements in worker training. To be precise, by means of Agreements drawn up between the above-mentioned parties, a simulator was designed and incorporated as the basis of a training station within the " Fundación Barredo" of the Industry Council of the Principality of Asturias. This has been operative since the year 2001 and, up to the present, 2300 Asturian coal mine workers have been trained there. What prompted this activity was the observation of various errors in the use of the self rescuers, deriving from their innate characteristics, especially with respect to the sensation of discomfort - the high temperature and humidity of the breathed oxygen, resistance and inconvenience - and limited autonomy. It was precisely this insight that, in critical situations, lack of familiarity with the conditions of discomfort likely to be experienced during the evacuation process might lead to rejection of the equipment, with fatal consequences, that has justified the setting up of this training and simulation centre. The centre is able to provide all mine workers with the necessary training, and experience of the characteristic sensations experienced when using such equipment (Fig.. 1).

Jan 1, 2003

While some of the practical details of ilmenite smelting are not well documented, there is a substantial body of literature on the principles of ilmenite smelting, and the behaviour of solidified titania slag. This information is summarized, focusing on the basic reactions, departure from equilibrium, the behaviour of impurities, and reactions of solidified slag. The emphasis is on the South African operations.

Jan 1, 2007

By D. Bessinger, H. Kotzé, J. Beukes

Keywords: Pyrometallurgy, furnace, ilmenite, smelting, Ticor Ticor SA began with a detailed feasibility study in 1995. The Hillendale mine (situated between Richards Bay and Empangeni) and Mineral Separation Plant were approved in 2000. The smelter, just outside Empangeni, consists of two 36 MW DC arc furnaces that were commissioned in 2003. Experiences gained during the initial commissioning of the furnaces proved valuable in later commissioning work, as shown by the increase in ramp-up rates. The capacity of the plant is 250 kt/a TiO2 slag and 145 kt/a of pig iron.

Jan 1, 2006

By Y. Suzuki, H. Yoshida, K. Sakaguchi, K. Matsuki, M. Minami

To estimate three dimensional in-situ stress at great depth, Downward Compact Conical-ended Borehole Overcoring (DCCBO) technique, which is one of stress relief methods, was developed. DCCBO technique can be applied to a water-filled vertical/sub-vertical borehole. In in-situ tests, the bonding device and the cleaning system were verified to work well in a water-filled borehole with cuttings on the bottom. Um dreidimensionale in-situ Beanspruchungen in großen Tiefen abzuschätzen, wurde das Downward Compact Conical-ended Borhole Overcoring (DCCBO) Verfahren entwickelt, wobei es sich um ein diese Beanspruchungen entlastendes Verfahren handelt. Die DCCBO Technik kann auf wassergefüllte vertikale und subvertikale Bohrlöcher angewandt werden. Bei den in-situ Tests wurde die Einsatzfähigkeit der Verbindungsvorrichtung und des Reinigungssystems für wassergefüllte Bohrlöcher mit Einschnitten am Boden bestätigt. La technique de Downward Compact Conical-ended Borehole Overcoring (DCCBO) ou ‘Surcarottage par sondage à extrémité conique compact dirigé vers le bas’, qui est une méthode de détente des tensions, a été développée pour calculer les tensions in-situ à trois dimensions à grande profondeur. Cette technique peut s’appliquer à des sondages verticaux/sub-verticaux remplis d’eau. Au cours des essais in-situ il a pu être vérifié que le dispositif de liaison et le système de nettoyage fonctionnaient bien dans un trou de forage rempli d’eau avec saignées au fond.

Jan 1, 2003

By C. E. Hales

In an effort to improve efficiencies and reduce costs, AngloGold has embarked on a process to develop and deliver consistent, high quality, tailings based support or construction products to stopes and tunnels on request. A three-phase approach of product conceptualisation, design and delivery has been adopted. To date a substantial amount of laboratory development has taken place with promising results, indicating that the project aims are achievable. Dans un effort pour améliorer le rendement et réduire les coûts, AngloGold s’est embarqué dans une opération qui vise à développer et fournir aux chantiers d’extraction et tunnels, sur demande, des produits de construction ou de support basés sur rejets qui sont réguliers et de haute qualité. Une méthode à trois volets a été adoptée : conception, création et livraison. A ce jour, un développement important en laboratoire s’est produit, avec des résultats pleins de promesses, qui semblent indiquer que les buts du projet peuvent être atteints. In der Bemühung, die Effizienz zu steigern und Kosten zu verringern, hat AngloGold begonnen ein Verfahren zu entwickeln welches auf Anfrage konsistent hochqualitative auf Haufwerk basierender Unterstützung oder Bauprodukte für Abbaustellen und Tunnels entwickelt und liefert Eine Dreiphasenplan zur Produktkonzeptualisierung, Design und Lieferung wurde adoptiert. Bis jetzt hat eine substantielle Anzahl an Laborentwicklung mit vielversprechenden Resultaten stattgefunden und aufgezeigt, daß die Projektziele erreichbar sind.

Jan 1, 2003

By P. Beukes, D. Bessinger, R. Glenewinkel

High titania slag is produced by the smelting of ilmenite and a suitable carbonaceous reductant in electric furnaces. Currently liquid slag is cast into large blocks, which take about 10 days to cool down before they can be crushed, milled and classified into two final products. The two products, chloride and sulphate grade slag, are differentiated according to their size. Granulation of titania slag has been identified as a possible alternative to the conventional block route. This paper discusses some of the work carried out at Exxaro Research and Development to investigate both wet and dry granulation of titania slag.

Jan 1, 2007

By A. A. Hazell

Mine management by objectives by A. A. Hazel Published in the Journal, September 1972 DISCUSSION H. H. McGREGOR Mr Hazell is to be complimented on a thoroughly down to earth analysis of the uses ot which work study can be put and the benefits of properly applying it in the management of underground production.

Jan 9, 2007