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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

"Sampling error and bias, especially the Increment Preparation Error (IPE), are introduced when the tool allocated to do the job fails to extract a representative sample. This is the case with chip sampling; the tool can only extract haphazard shapes of loose or fractured material and not always from within the demarcated sample area. Increment Extraction Error (IEE) and Increment Delimitation Error (IDE) could be severe, but are found to be relatively unbiased. The uncontrolled action of the sampler in discarding excess sample material after sample collection has a significant impact on the error and bias introduced with each and every extraction. A new type of bias, referred to as the ‘waste discard bias’, arises when samplers select what portion of the excess sample material to discard at the sample site. Material visually identified as waste is discarded in preference to mineralized broken ore if there is an excess of sample material. This results in a considerable error in the analytical results. The bias is proportional to the reef-waste ratio in the demarcated sample. IntroductionTwo types of ‘sampling’ are distinguished, namely sampling of particulate materials (broken ores) and sampling of solid, unbroken in situ mineralized reef. This study considers only chip- or face-sampling of in situ, goldbearing, carbon-rich conglomerates typical of the Upper Witwatersrand Supergroup and examines where components of sampling error and bias, clearly specified in the Theory of Sampling, may arise during the practice of ‘face sampling’. Many millions of face samples have been extracted from Witwatersrand-type mines using a hammer and chisel, and detailed descriptions (standard operating procedures) of how the samples should be taken have been developed by many mining companies. There is, however, no taxonomy or nomenclature for managing or reporting the different types of errors associated with chip sampling. The Theory of Sampling compiled by Pierre Gy in the early 1950s provides, comprehensive nomenclature of sampling errors that is applied to particulate sampling of ore in a lot, a stockpile, or a moving stream on a conveyor belt. The taxonomy and characteristics of sampling errors, grouped according to the sources from which they arise, and identified by Gy (1973, 1979, 1982, 1992, 1995, and 1998) are shown in Figure 1. This classification of errors is used extensively in regard to the sampling of particulate materials in the mining and minerals industry, but not in regard to chip sampling. A relatively small mass (hundreds of grams) of representative particulate material for estimating the average grade of a much larger mass (thousands of tons – the ‘lot’ in the Theory of Sampling) is extracted by the chipping or cutting of a representative rock ‘sample’ from the stope face."

Jan 1, 2016

By J. Autio, H. Malmlund

The excavation damage zone (EDZ) caused by drill and blast excavation consists of intense damage adjacent to the remaining half barrel of the blast hole, new fracturing induced by the blast and reactivation of pre-existing fractures. The properties of intense microfracturing adjacent to the half barrels of remaining blast holes are based on study of rock samples from ZEDEX-tunnel and it’s extension at Äspö and the Research tunnel at Olkiluoto in Finland. The new and reactivated fracturing is based on results of mapping of slots cut in the rock in ZEDEX-project. The zone of increased porosity adjacent to half barrels, which penetrates to a depth of some centimeters was studied by using novel 14C-PMMA method. The penetration of the radial fractures, which is an order of magnitude deeper, was studied by mapping using color penetrant. Results of EDZ studies carried out at Äspö HRL in Sweden and in Research Tunnel at Olkiluoto show that the properties of EDZ can be affected significantly by engineering design. The result imply that the additional pore volume caused by distinct fracturing around the blast holes caused by state-of-the-art smooth blasting technique could be of the same order as that of the damaged zone adjacent to the surface of the half barrels. Durch Bohr- und Sprengarbeiten entstandene Eigenschaften der Auflockerungszone: Die durch Bohr- und Sprengarbeiten entstandene Auflockerungszone besteht aus einem großen, an das Resthalbrohr des Bohrloches angrenzenden Schaden, neuer Rissbildung und einer Reaktivierung der bereits existierenden Risse. Die Eigenschaften einer immensen, an die Halbrohre der Restbohrlöcher angrenzenden Mikrorissbildung beruhen auf einer Studie über die aus dem ZEDEX-Tunnel gewonnenen Gesteinsproben und deren Fortsetzung im Untertage-Labor Äspö (Hard Rock Laboratory, HRL) in Schweden und im Forschungstunnel bei Olkiluoto in Finnland. Die neue und reaktivierte Rissbildung basiert auf den Auswertungsergebnissen der Schlitze, die bei dem ZEDEX-Projekt ins Gestein geschnitten wurden. Die Zone der vermehrten, an die Halbrohre angrenzenden Porösität, die in ein paar Zentimeter Tiefe eindringt, wurde anhand der neuen 14C-PMMA-Methode untersucht. Das Eindringen der etwas tiefer gelegenen radialen Risse wurde anhand eines farbigen Eindringungsmittels untersucht. Die in Äspö und Olkiluoto durchgeführten EDZ-Studien zeigen, dass die EDZ-Eigenschaften wesentlich durch Engineering Design beeinflusst werden können. Das durch Bohrarbeiten verursachte Hohlraumvolumen der Rissbildung um den Tunnel herum ist ähnlich wie das Hohlraumvolumen der Bruchzone um die Bohrlöcher herum. Caractéristiques d’une zone endommagée par le creusement résultant d’un creusement par forage et dynamitage: La zone endommagée par le creusement résultant d’un creusement par forage et dynamitage présente un endommagement intense adjacent au demi-cylindre restant du trou de mine, une nouvelle fracturation et la réactivation des fractures préexistantes. Les caractéristiques de la microfracturation intense adjacente aux demi-cylindres des trous de mine restants reposent sur l’étude des échantillons de roche en provenance du tunnel ZEDEX et de son extension au laboratoire souterrain d’Äspö (« Hard Rock Laboratory » ou HRL) en Suède et du tunnel de recherche d’Olkiluoto en Finlande. La fracturation nouvelle et réactivée repose sur les résultats du placement des rainures sur la roche dans le projet ZEDEX. La zone de porosité accrue adjacente aux demi-cylindres et pénétrant à une profondeur de quelques centimètres à fait l’objet d’études recourant à la nouvelle méthode 14C-PMMA. La pénétration des fractures radiales, considérablement plus profondes, a été étudiée par placement en utilisant un agent pénétrant coloré. Les résultats des études EDZ effectuées à Äspö et à Olkiluoto montrent que les caractéristiques de l’EDZ sont susceptibles d’être affectées de manière significative par la conception technique. Le volume vide de fracturation résultant du dynamitage autour du tunnel est du même ordre que celui de la zone concassée autour des trous de mine.service.

Jan 1, 2003

By G. T. Lineberry, C. M. Baird, D. L. Silverstein

The University of Kentucky (UK), with an enrollment of 25,891 in fall 2002, is a comprehensive, public land-grant university located in the Bluegrass Region of Central Kentucky. As the State’s flagship university, UK has long been involved in distance education, first through traditional correspondence courses, followed by use of videotape and satellite delivery in the 1970s and1980s, but soon supplanted by use of interactive television (ITV) and on-line course delivery in the 1990s to date. Today, UK Distance Learning Programs annually administers approximately600 course sections, with services provided to over 5200 enrollees. Courses are offered via six media: interactive video, Internet, on-site, satellite, open-air and cable television, and videotape, with hybrid delivery becoming increasingly popular. The University of Kentucky College of Engineering experience with distance instruction prior to 1985 was limited to videotape non-credit offerings. The Department of Mining Engineering, a small department in terms of numbers of both faculty and students, was a University pioneer in distance education. The first University degree program offered in its entirety by distance delivery(initially by itinerant faculty) was the Master of Mining Engineering. Satellite delivery from Lexington to Cumberland, Kentucky, was a welcomed change of delivery mode in 1987–88,resulting in six hours less travel time for faculty each week. Shortly thereafter, other initiatives directed toward fulfilment of its land-grant mission were undertaken by the College. Use of satellite for course delivery rapidly declined due to limited interactivity, in favour of compressed video and on-site instruction. Classroom sites in the Kentucky Tele-Linking Network (KTLN) now number over 200. The Network links schools, colleges and universities, as well as public and private agencies throughout the State. The KTLN supports voice, video, and data transmission in a uniformly-equipped environment. Beginning in the early 1990s, transfer-critical pre-engineering courses were delivered from Lexington to Kentucky’s community colleges with the largest pre-engineering enrolments. Success was limited, but lessons learned were invaluable. In 1996, the University of Kentucky College of Engineering was asked by the Kentucky Council on Higher Education (the predecessor to the Council on Postsecondary Education) to expand engineering education in Kentucky, first by initiating cooperative B.Sc. degree programmes in Chemical Engineering and Mechanical Engineering on the campus of Paducah Community College (PCC), located 400 km from the UK campus in Lexington. The third partner in these programmes is Murray State University (MuSU), a public regional comprehensive university 80 km south of Paducah. The genesis of the new degree programmes, which were subjected to ABET review in October 2002, as well as a summary of the major accomplishments and challenges of the innovative programmes, will be offered. The limited use of distance technologies for course delivery in these B.Sc. degree programmes will be discussed. A ‘no-spin’ overview of other non-traditional distance-learning ventures within the College of Engineering will be chronicled, with an honest assessment of the motivation for these efforts and, where appropriate, their relative degree of success. Among these ventures are: a BScME and a Master of Engineering programme at Toyota Motor Manufacturing of Kentucky, Georgetown, Kentucky; course exchange in Chemical Engineering between the University of Kentucky and the University of Louisville; an ITV-based Master of Engineering programme for practicing engineers in Kentucky; proposed joint-degree programmes in Civil Engineering and Mechanical Engineering with Western Kentucky University; and a proposed part-time MScME programme in Paducah, Kentucky, with a start date of August 2002, threshold enrolment permitting. Keywords: distance learning, distance education.

Jan 1, 2003

By H. G. Mosenthal

In any mining enterprise, the extraction of the ore from the orebody is of vital importance. This activity is stoping. The gold mines of the Witwatersrand and its extensions in the Klerksdorp, Welkom, and Evander areas form the most extensive goldfield in the world. This address reviews stoping technology and improvements in this technology since the end of the Second World War. Although the reefs that make up the Witwatersrand orebody are uniquely extensive, they are not suited to mechanized mining. This is due to a number of factors such as the depth of the orebody, its narrowness, and the hardness and abrasiveness of the quartzite forming the orebody. The most notable improvements in stoping technology have been brought about because of our beter understanding of rock-engineering problems. This has resulted in beter layouts, stoping geometry, systems of aleviating rock stresses, and support systems. It has enabled the industry, at ever-greater mining depths, to maintain and even increase productivity. These improvements, based on rock engineering, have significantly reduced the accidents due to rockbursts. There are many diferences between today's stoping and that practised forty years ago. Panels are shorter, concentrated mining has superseded bench mining, and the support systems are certainly better. Yet the face scraper is still used extensively, as are pneumatic rock drills. Some innovative stoping systems that have given rise to improved productivity are discussed. Explosives technology has shown spectacular advances during the period under review. Sadly, our local industry has had little to do with this research and development, but has been most adaptive in using the new products on offer.

Jan 1, 1990

A. H. Mokken: I am pleased to have been given this opportunity to make a contribution to Dr Muller's paper tonight. The reason for this is that, at one stage in our careers, we were associates in the same undertaking. Dr Muller, then fresh from University, with a degree in pure science, had just stepped onto the first rung of the ladder, which, it was then thought, would lead him to a career in gold extractive metallurgy. However, endowed with an enquiring mind and conscious of a lack of fundamental training in general metallurgy and engineering, he felt a need for further academic study. To meet this need and, more importantly, to meet the necessary finances, he found his opportunity in steel. Armed with a bursary, he bade farewell to gold and proceeded overseas, to the University of Sheffield, to train as a steel metallurgist. The outcome of these academic efforts, which were followed by assignments in the steel industry and a further period at Sheffield, is the man we have listened to tonight-a highly qualified metallurgist who has displayed a sound knowledge of his subject. In choosing Sheffield, Dr Muller became associated with a steelmaking centre of world renown, a centre usually credited with the first systematic production of alloy steels, as far back as the 18th century. Since that time, great advances have been made in the production of alloy steels and this is especially so in the last decade or two, when major developments in civil, mechanical, electrical, aeronautical and nuclear engineering have been made possible by the development of steels with improved properties. In spite of spectacular advances in the technology of non-ferrous alloys, plastics and other materials of construction, steel has maintained its role as a pre-eminent material for engineering use. With the gradual accumulation of data on the properties of steels, and the use of thin film electron microscopy, to study the behaviour and characteristics of such phenomena as dislocations in metals and other microstructural features, the physical metallurgist appears to be approaching the stage of an exact understanding of such phenomena as strength, ductility and brittleness-a knowledge which could lead to close control of such properties and, therefore, to the attainment of the highest goals. An interesting example, illustrating the use of fundamental principles, based on physico-metallurgical research, is the development of the maraging steels developed by Bieber at the International Nickel Company. These steels have met the extreme technological requirements of the space age by providing the material for the cases of large rockets in which qualities, such as high tensile strength, toughness, workability and weldability are most important. Attractive as they might appear to be in considerations of savings of weight, cost of erection, transport of materials and foundations, the use of high strength steels has been accompanied by special problems such as brittle fracture, hydrogen embrittlement, notch-toughness and fatigue. It has been found that high strength steels, which performed acceptably in conventional tension tests, were found to undergo failure, in a brittle manner, in service. Hydrogen embrittlement has caused spectacular failures at a fraction of the normal ultimate tensile strength, and a lack of correlation between fatigue and tensile strengths has diminished the advantages to be obtained from the use of high strength steel in some applications. A new approach to the selection of materials for engineering design has resulted from a consideration of these phenomena in which strength, as such, is no longer as significant as it was previously. Parallel with the development of high strength steel has been the need for suitable techniques for joining component parts and here welding has played an

By T. Ito, N. Tokashiki, H. A. Bilgin, Ö. Aydan, T. Akagi

This study is concerned with the electric potential induced by deformation, fracturing and sliding of non-piezoelectric geomaterials. In experiments, the acoustic emissions together with electric potential measurements were also measured in order to see how the so-called seismic electric signals are associated with new fracture occurrence and propagation and sliding in case of existing discontinuities. The outcomes of this experimental study may explain why such electric potential variations may occur during the fracturing and sliding of non-piezoelectric geomaterials. On the basis of these outcomes, their possible implications in geo-engineering and geo-science are discussed. Ce travail concerne 1e potentiel électrique produit par la déformation, 1a fracture ou le glissement du matériel géologique non-piézoélectrique. Aux expérimentations, on a mesuré 1es émissions acoustiques avec le potentiel électrique afin de constater la relation entre les phénomènes de glissement ou de formation et de propagation de nouvelles fractures le long des discontinuités existantes. Les résultats de ce travail expérimental expliquent pourquoi de telles variations de potentiel electrique se produisent durant le glissement ou la fracture du matériel non-piézoélectrique. Sur la base de ces résultats, on a discuté de leurs éventuelles implications dans les domaines de 1a géologie et de 1a géo-ingénierie. Diese Studie befasst sich mit dem elektrischen Potential das durch die Deformation, Bruchbildung und Gleiten von nicht-piezoelektrischen Geomaterialien induziert wird. In Experimenten wurden die akustischen Emissionen zusammen mit elektrischen Potentialmessungen gemessen, um zu sehen, wie die so genannten seismischen elektrischen Signale mit neuer Bruchbildung und Ausbreitung sowie Gleiten im Falle von vorhandenen Diskontinuitäten verbunden sind. Die Ergebnisse dieser experimentellen Untersuchungen könnten erklären warum elektrische Potential Schwankungen während der Bruchbildung und dem Gleiten von nicht-piezoelektrischen Geomaterialien entstehen. Auf der Basis dieser Ergebnisse, wurden ihre möglichen Implikationen in Geoingenieurwissenschaften behandelt.

Jan 1, 2003

By D. Borman

The location of underground positions in mines has usually fallen to their survey department's. Their usual tasks include: ? installation of a high-precision peg network like the National Survey grid as beacons ? offset measurements to the sidewalls, and sometimes hangingwall and footwalls, of development tunnels and excavations ? offsetting of stoping panels for the calculation of face ? advance and the square meterage of area removed. Other departments build their observations into the plans produced by the surveyors. If more precision is required, they ask the surveyors to `elevate' their points with a theodolite. Apart from the survey peg network and `elevations' these measurements are usually planer measurements suitable for producing plans, sections and projection sheets. When the only representation medium was a sheet of paper or transparency, this was perfectly suitable. However the development of CAD models of the workings has changed all this. Full 3D representation is not properly catered for in the tool sets in current use, and needless hours are spent converting analogue-type observations into digital form. The basic survey models need to be augmented by the observations of other disciplines that are also required to locate positions underground. These include: ? the need for geologists to plott their mapping and ? borehole logs into 3D space ? the need for samplers to position their sample points accurately because the geostatistical models are biased and inaccurate ? the need for stoping width recorders to position their thickness observations to prevent errant evaluation and bonuses ? the need for rock engineers to place their mappings into 3D to build true geotechnical models to manage geotechnical stresses ? the need for production officials to receive updated face ? positions during the month so that they can manage the ? production and utilize their resources properly. This paper covers a new method of positioning profiling points to a suitable degree of accuracy. I believe the method is sufficiently simple and cheap for all to use. Historical methods Platinum and gold orebodies, especially in South Africa, are generally narrow tabular deposits. This made them suitable for depicting on a 2D medium like paper. The determination of stoping or face widths was not a problem, as the ore is removed in a single stoping process. Such 2D representations could be easily positioned using tape offsetting between survey pegs or points tied in from survey pegs. Problems of dip were handled by using 'Stope Sheets' which chose a best fit projection for the whole area depicted or by using true dip section sheets for inclined tunnels. Rolling reef and potholes were the common areas of difficulty. Most mines now model their orebody and plan the extraction in computer graphics. This means that the representation of the current workings has to change to support this trend. It now becomes a truly 3D problem. Mining officials find it inconvenient to have their actual workings in single-line depictions while their orebody is depicted with top and bottom contacts and the planned tunnels in 3D shapes. Geological models which form the basis for the resource model and planning process are often out of date, as the updating process is slow. The geological mapping has to be plotted onto sections and plans. These are then digitized into graphics by a draughtsman and checked by the geologist. Only then does the interpretation and model update take place. Potential methods to create 3D 'Actuals' Global positioning systems (GPS) Surface mines have been blessed by the advent of GPS technology. These simple-to-operate pieces of equipment and compatible software make it possible for all types of mine employees to locate themselves, and therefore to locate their observations. GPS are often inexpensive and give an acceptable degree of accuracy. Only in deep pits or close to the highwalls are observations hindered. Such technology cannot however, work underground. Ground penetrating radar (GPR) GPR is reported to be very useful for estimating the positions of potholes and faults. However it is still considered as providing an estimate, not a definite measurement. GPR is good for seeing into solid rock, not into open spaces. Inertia reading devices Experiments with inertia reading devices have been conducted on the mines. They were the forerunners of GPS for military guidance systems, and were even used for city navigation in the early 70s. They do however work best with heavy or fast-spinning gyros. Anglogold Ashanti's attempt to use them were discontinued in the mid-90s when the developers asked for an additional few million rand for a device that would weigh more than 12 kg and have a limited operational life.

Jan 1, 2006

By J. F. Morrison, C. H. Wyndham, N. B. Strydom

INTRODUCTION The shovelling of rock in stopes is still a basic and important operation in many gold mines in the removal of gold-bearing rock from the stopes. There is, however, little factual knowledge of the factors which influence the the rates of energy expenditure and work output, and of the way in which variations in these factors, individually or in combination, affect the mechanical efficiency of the mine workers. What for example is the influence of different rates of shovelling, shovel loads and distances of throw? How does stope width and dip of the stope affect the mechanical efficiency of men shovelling rock? Recently a simple physiological test was introduced into the gold mining industry for classifying Bantu recruits into those capable of hard, moderate and light work. If this test is used to select only those Bantu mine workers who are capable of hard work for the task of shovelling rock in stopes then the rate of energy expenditure which could be expected from these men is 1.5 litres/min for the entire period of the shift. With an adequate knowledge of the influence of the various factors which affect the rate of energy expenditure of men shovelling rock in stopes it would be possible to set work standards for Bantu mine workers in stopes. This should be done in terms of the rate of shovelling, the shovel load and the distance of throw for any combination of width of stope, dip of stope, condition of foot wall and grade of rock in such a way that the resultant energy expenditure would be the 'optimum' that could be expected from the men but would be within their capacities for physical work of an endurance nature (that is, 1. 5 litres/min from the 'average' Bantu mine worker). Work standards could thereby be determined for the different stopes of a mine on a sound and systematic basis. In order to supply the information required a study was carried out by the Human Sciences Laboratory in which the work output and energy expenditures (in terms of oxygen consumption in litres/min) were measured on six highly trained Bantu mine workers under the following conditions: (a) rates of shovelling of 3, 4, 5, 6, and 10 shovels per minute. (b) loads of from 9 to 18 lb on the shovel. (c) distances of throw from 8 to 20 ft. (d) stope width of 28 in., 42 in. and 72 in. (e) dip of stopes of 0°, 15° and 30°. (f) rough and smooth footwalls and various grades of rock size. This paper gives the main results of practical importance of this study. Method The experiments were designed and conducted in conjunction with the Work Study Department of one certain underground conditions such as variable stope widths, stope angle, etc., were made available in a mine Surface Training School and suitable subjects were selected from the large number of labourers being put through the training school. Subjects Bantu recruits who had returned to the mine for a new contract and who had previous underground experience on shovelling were considered to be suitable as subjects for the experiments. The particulars of the subjects are given in Table I. TABLE I PHYSICAL CHARACTERISTICS OF SUBJECTS Weight Height Surface area Max O2 capacity Subject (Kg) (cm) (sq meters) (Litre/minute) A 71.5 167.3 1.80 3.5 B 61.5 162.3 1.65 2.8 C 63.0 164.1 1.69 2.4 D 66.5 167.4 1.75 2.8 E 70.2 164.6 1.77 3.0 F 77.8 173.1 1.92 3.8 Training The method of shovelling, accepted by the Work Study Department, was demonstrated to the subjects who then practised the movements with empty shovels, under the supervision of an instructor. After the technique was mastered, the men started shovelling rock and were trained for at least four hours per day to work at the higher shovelling rates. Training was continued for three weeks to enable the subjects to achieve a reasonable degree of physical training and conditioning. Shovelling method In both the kneeling and standing positions the subjects faced the pile of rock, grasped the shovel in the accepted manner and pushed the blade of the shovel into the base of the pile of rock, sliding the blade between the rock and the concrete floor. In the standing position (72 in. wide stope) the back leg assisted in the movement by pushing the knee against the back of the hand holding the shovel handle. In the kneeling position the elbow was tucked into the side of the body so that the muscles of

The theory of geostatistics covers a branch of .applied statistics aimed at a mathematical description and analysis of geological observations. Geostatistics can be used in pure geology (for example, for the analysis of trace elements in a metamorphic rock), in mineral exploration (for example, for the analysis of geochemical exploration data), as well as in mine valuation. This book is intended to provide a practical introduction to the theory of geostatistical methods of mineral evaluation. Over the years, various mathematical models have been developed to represent the distribution of values in mineral deposits. The simpler models are based on the assumption that the values are randomly distributed. Classical statistical methods, based on this assumption of the random distribution of values, are used to analyse mineral deposits to which these models apply or are assumed to apply. In all mineral deposits, however, one recognizes the presence of areas where the values are higher or lower than elsewhere. Also, the values of two samples in a mineral deposit are more likely to be similar if the samples are taken close together than if they are taken far apart. This indicates that there exists a degree of correlation between sample values, and that this correlation is a function of the distance between the samples. Models have been developed which take this correlation into consideration, with the degree of correlation between sample values being usually measured by the semivariogram function. In these models the fact that two samples taken next to each other will most probably not have the same value, must also be considered; even for very short distances the correlations are usually not perfect and a purely random component is present in the value distribution. The mathematical models will therefore assume the presence of two sources of variability in the values: a correlated component and a random component. Finally, one must consider the particular and very common case of mineral deposits in which the values present a systematic variation in space. This variation is usually referred to as a drift, or a trend. For example, the grade of an ore body may increase with depth of the ore, or it may decrease when one moves away from a central volcanic pipe. The earlier models did not give a satisfactory representation of drifts, and more complex models have been developed, in which three sources of variation are represented. These models are made up of: a deterministic component, a correlated component, and a random component. The deterministic component is used as a model of the drift. The correlated component explains regular changes in values which are not represented by the drift. The random component represents variations which cannot be explained by any of the above factors. The simpler models, based on the assumption of a single random component, will be described first (Chapter 2). The models based on the hypothesis of the superimposition of a correlated component on a random component, will then be analysed in detail. These models are most commonly used in the analysis of mineral deposits (Chapters 3-1 I). Finally, how to deal with the presence of a drift will be briefly described (Chapter 12). This book has been written essentially for students in mining engineering and for mining engineers who are interested in the background to the theory of geostatistics as well as its practical applications. The assumption is made that the reader has an elementary knowledge of statistics. Some knowledge of linear algebra is useful in part of Chapter 9, and is necessary to read Chapter 12. A proof is given of all the equations related to geostatistics, and which are not usually found in elementary textbooks on statistics. Understanding of these proofs is not necessary for practical application of the theory, and the reader may wish to skip them on a first reading, concentrating attention on the numerous simple practical examples given. Although the theoretical geostatistician will not find much new material in this publication, it is anticipated that he will develop some interest in the practical approach chosen to prove the various geostatistical equations. Many people and institutions contributed to the preparation and completion of this work. I am much indebted to Dr D. G. Krige and the Anglo Transvaal Consolidated In- vestment Company Limited, who gave me the opportunity to spend a considerable amount of time working on geostatistical problems, both theoretical and practical, during the time that I was in their employment. Dr Krige contributed greatly in developing my interest in studying both the theory and practice of geostatistics, always insisting that a correct balance be kept between theory and practice. I am grateful to Professor H. M. Wells and the Mining Department of the University of the Witwatersrand for inviting me to give lectures in a post- graduate course on geostatistics. The notes 1 prepared for that course became the foundation of the present work. I am also indebted to the Centre de Geostatistique of the École des Mines de Paris, where I received my first formal education in geostatistics during a summer course given by Charles Huijbregts, after many years of my lonely plodding through the published literature. Many graphs in the present volume are reproduced with the permission of the Centre de Geostatistique. The Department of Metallurgical and Mineral Engineering of the University of Wisconsin-Madison has also contributed in making this work possible, by allowing me to spend a considerable amount of time and resources in the writing, typing, and correcting of successive drafts. I am thankful to Lynn D. Kendall, who typed the entire manuscript under constant pressure.

Jan 1, 1978

By M. I. Brittan

Discussion Dr R. E. Robinson (Fellow): The author must be congratulated on a very meticulous and self-contained piece of work. It is indeed a pleasure to read a paper that is so clearly and systematically laid out, and where the conclusions and the testwork conducted have been so clearly described. The paper is complete in itself, which makes it very difficult for someone who is not intimately involved in the whole Torco project to make any comments on its content. However, two points that, strictly speaking, fall outside the scope of the paper are of considerable interest. The first relates to the particle size of the material treated. In the paper, the testwork is confined to one standard particle size (minus 60 plus 100 mesh). The essential feature of the paper is to indicate that the rate-controlling reaction in the whole segregation process is the rate of reaction of the ore particles with the reducing agent and the hydrogen chloride. One wonders, therefore, to what extent this relatively slow rate of reaction is affected by the particle size of the ore itself. One imagines that the reaction must take place by contact of the hydrogen chloride with the surface of the mineral particles, and it is reasonable to suspect that the rate of diffusion of the copper ions to the surface is a relatively slow process and is thus the limiting factor in this particular rate of reaction. It is possible, for example, that the improvement obtained, when the ore is subjected to reducing conditions before the chlorination, is due to a breakdown in the crystal structure of the original particle. This breakdown is brought about by the reduction and by the consequent increase in surface area available for reaction with hydrogen chloride. Can the author indicate whether any work has been done along these lines, and whether it has been established that the reaction depends on the surface area available? The second point relates to the application of this kinetic study to the actual operation of a Torco reactor. It was once planned to feed the sodium chloride, together with the reducing agent, into the top of the segregation chamber. In the paper, the author mentions that it has now been established that the segregation chamber behaves, to all intents and purposes, as a fluidized bed, and that there is, therefore, a rapid evolution of gas in the lower regions of the chamber, which, it is imagined, displaces the gas phase rapidly. Since the reaction between sodium chloride, water vapour, and the aluminium silicates in the ore is extremely rapid, one wonders how much of the hydrogen chloride produced is removed from the reaction zone before it has had time to react with the copper minerals. The extremely low consumption of sodium chloride (which is a vital feature of the Torco process) must depend on an extremely rapid circulation of the hydrogen chloride gas to all the ore particles in the segregation chamber. One wonders, therefore, if a system for the introduction of the sodium chloride into the bottom regions of the chamber might not result in even greater efficiency in the utilization of sodium chloride. ProC D. D. Howat (Fellow): All of us who have been concerned with the study of chemical reactions at high temperatures are keenly interested in kinetics and are well aware that this is not an easy study experimentally. Dr. Brittan is to be congratulated on the development of neat experimental methods and for his full discussion of the results obtained. Although the segregation process for the extraction of copper from oxide and silicate ores has been known for almost fifty years, the fundamental chemical and physical changes involved have been little understood and the fundamental data are very scanty. The work now in progress at A.A.R.L., together with that sponsored by the Anglo American Corporation in other research institutions throughout the world, is bound to produce new fundamental data and a much more complete understanding of this rather fascinating process. It is already apparent that some of the old and well-worn chemical reactions that were postulated to occur, just cannot take place in the way which was formerly accepted. Dr Brittan's work, carefully conducted and thoroughly analyzed as it has been, still leaves us with one great outstanding problem. The thermodynamic data and the possible reactions set out in Table I (page 281) of his paper leave us asking, in complete despair, how can copper be converted into a volatile chloride in the presence of HCl, CO and carbon at temperatures about 800°C? The thermodynamics all combine to show that copper should be reduced to metal as the first step in the process. This brings us right up against the second problem. If copper were reduced to the metal how would HCI convert it to the volatile chloride? On top of these problems is the unknown reason for the very high speed of reaction between CO, HCI and the ground copper ore. Still further into the region of the unknown is the reaction by which gaseous hydrochloric acid is produced in the actual process. Perhaps Dr Brittan is feeling grateful that he doesn't have to try to explain this reaction-at this stage of the research programme at least. The results very clearly show that both CO and HCl gas are essential for rapid production of the volatile copper chloride. Dr Brittan states that 18 minutes were required to attain 83 per cent extraction with HCl gas alone and this was reduced to 4 minutes when CO was

Jan 2, 1970

Colloquium and General Meeting were held at Kelvin House on 19th May, 1971, the theme being 'Modern trends in coal mining practice.' Mr V. C. Robinson (President) was in the Chair. The Colloquium was attended by 205 delegates and was opened by the President at 9 a.m. OBITUARY The President: 'It is my sad duty to announce the death of C. C. Cullen, Fellow, who joined the Institute in 1946 and passed away on 15th March, 1971. As a mark of respect to the memory of the deceased and in sympathy with the bereaved I would ask you all to rise and observe a few moments silence'. ELECTION OF SCRUTINEERS The President: 'In terms of Clause 9.4 of the By-Laws I now call for the nomination of seven Corporate Members to act as scrutineers of the ballot for Council'. Messrs V. C. Robinson, Prof D. D. Howat, Dr J P Hugo, D. G. Maxwell, J. K. E. Douglas, R. J. Adamson and P. Lambooy were nominated by P. W. J. van Rensburg and seconded by P. A. von Wietligh. The President: 'Are there any further nominations? If not I declare these gentlemen elected.' MEMBERSHIP The President: 'I have much pleasure in announcing that the names of candidates, having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute in the following grades: Members: Douglas Edward King, Bryan Rudolph Scott, James Gregor Phimister, Anthony David Walters. Graduates: Cornelius Johann Muller, Marthinus Stephanus Mulder. Associates: John George Everson, Colin Robert Llewellyn Davies. Students: Francois George Enslin Beetge, Ewald Boshoff, Christiaan J. Cloete, Christopher John Davies, Cameron George Elvin, Kenneth Eric Field, Johannes Louis Fourie, Hans Gert Gastrow, Peter John Ledger, James Robert William Lindsay, Kynaston Lloyd McDonald, Richard Peter Mohring, Arthur Leslie Painting, Matthias Arthur Pascall, Ian Neil Sinclair, Donald Allan James Ross-Watt. MEMBERS TRANSFERRED TO A HIGHER GRADE From Member to Fellow: Peter Norman Roberts. From Associate to Graduate: Alfred Eric WaIter Fletcher. From Student to Graduate: Wilfried Pierre de Villiers, Edward Emile Eichenberger, William Alan Nairn, Lodewyk Johannes de Jager, Colin Henry Obray, John Grenig Rees. COLLOQUIUM The President opened the proceedings and introduced Mr N. W. S. Schumann as the overall chairman for the day. The following papers and contributions were presented: FIRST SESSION: Chairman R. C. J. GOODE. Paper: 'Problems encountered in the operation of a new colliery' by P. M. C. Wilson and A. A. Oakes. Contributors: D. J. Moloney, G. R. Canny, I. G. Evans, R. B. MacGillivray, Dr F. G. J. de Jager, M. J. Deats, and N. Zolezzi. R. B. MacGillivray Mr President and gentlemen, I would like to congratulate the authors on presenting a most interesting paper on a very important subject. After several attempts at finding suitable reserves to extend the life of Welgedacht Exploration Company's Utrecht Colliery a block of coal rights was acquired south west of the town of Utrecht. A study of these reserves showed that they would enable a satisfactory return on capital invested to be achieved. It was decided therefore to open up what is now called the Zimbutu section of Welgedacht Exploration Company, to produce 41 000 metric tons of coal per month. The decision to open this section was taken in August, 1968 and due to certain allocation requirements it was necessary to bring it into production by the 1st of January, 1970. Fortunately a fair amount of statistical data had been collected prior to August, 1968 from the old Utrecht Colliery in anticipation of opening a mine and a fairly detailed rechnical report had been prepared. As a result the dead line was only missed by four days. Main features of the Design A feasibility study was carried out on three possible shaft positions and the final position was selected from these three on economic grounds. As the coal seam at the selected shaft position was only 21 metres below the surface it was decided to sink two twin incline shafts to enable rapid establishment of through ventilation and alternative hauling arrangements for quick development. This also allowed the final vertical ventilation shaft to be placed at some distance away to avoid the nuisance of fan noise. Second outlet requirements are also very well met by these twin inclines. Again on the basis of economics and also due to the uncertainty of roof conditions it was decided to use hand loading methods underground. However, to allow for future possible conversion to mechanised loading, should this become economical through rising wages, a conveyor belt was installed in the hauling shaft. This conveyor belt is fed from an endless rope haulage in the east companion by means of tipplers, a bin and a feeder. The main development heading was left clear for the future installation of a conveyor belt which would afford easy conversion to mechanisation.

COUNCIL The following served on Council during the year under review: Office bearers: Messrs V. C. Robinson (President), Prof D. D. Howat and Dr J. P. Hugo (Vice-Presidents), J. K. E. Douglas (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Ordinary Members of Council: Dr M. G. Atmore, Dr J. M. Bereza, H. P. Carlisle, W. W. Malan, C. E. Mavrocordatos, Prof R. P. Plewman, Dr R. E. Robinson, Dr M. D. G. Salamon, P. W. J. van Rensburg, L. W. P. van den Bosch, P. A. von Wielligh. Branch Chairmen: J. Meintjes, J. M. Meyer (Acting), J. N. Saunders (Retired). Past Presidents serving on Council: R. J. Adamson, M. Barcza, H. Britten, R. C. J. Goode, P. Lambooy, Prof J. de V. Lambrechts, Dr J. T. Mclntyre, J. F. Reid, H. Simon. Ten Council meetings were held during the year with an average attendance of eighteen and the standing committees held forty-six meetings. FINANCE The annual accounts, which are attached to this report, show an excess of income over expenditure of R5 051 compared with an excess of expenditure over income last year of R4 608. This major reversal of fortunes is due in the first instance, of course, to the increased subscriptions. There were, however, other important contributors, particularly sales of the Proceedings of the Symposium on Open Pit Mining and profits on the operation of symposia and colloquia. It would appear from a study of the accounts that there has been a substantial drop in expenditure on secretarial fees. In actual fact, however, our total expenditure on secretarial fees was higher. A portion of this expenditure was charged against the administration of the Symposium on Open Pit Mining and, in addition, the charge against the Journal accounts for secretarial fees was increased. It will be recalled that in last year's annual report it was mentioned that subsequent to the new arrangement for publication of the Journal, the expected improvement in the finances of the Journal had been slow in materialising. After a total period of 18 months there was still no sign of improvement and it was accordingly decided to end the arrangement. As a result, the drain on the finances of the Institute was considerably lessened in the second half of the year. During the course of the year Council became concerned about the rapid depletion of our accumulated funds and gave careful and detailed attention to all aspects of the Institute's financial affairs. Particular attention was given to: 1. The fact that the Institute does not have a solid financial backing and must appeal for funds every time any special event such as a symposium is held. 2. The responsibilities of the Institute to the profession and the community, with particular reference to the desirability of establishing Institute bursaries and participating in other educational activities. 3. The rapidly rising cost of living. 4. The immediate financial position of the Institute. 5. The rapidly increasing cost of publishing the Journal due to the increasing number of papers available. In the meantime the immediate financial position of the Institute has improved but as this is due largely to non-recurring or irregular items of revenue, it should not be given undue weight. After careful consideration it was decided that an appeal should be made to industry for financial assistance, which would be used to cover the cost of symposia and other unusual expenditure and also, if possible, to build up the capital resources of the Institute so that there is a solid foundation for the future. Before appealing to industry, Council wished to be quite certain that there could be no criticism of the Institute for not having done our best in a personal capacity. Furthermore, Council examined many comparative statistics, including those circulated to members, which showed that, while expenditure per member has risen at an average annual rate of 7,5% over the last fifteen years, subscription revenue per member has risen at only 3,4% per annum. It was with this background that your Council decided to raise the subscriptions. Initial approaches have been made to the big mining groups and there has been a very generous response, although the details of how financial assistance will be provided have not yet been worked out. It seems likely that some form of affiliated company membership will be the most suitable method of achieving this. When these details have been fixed, it is the intention to extend the appeal to all corners of the mining industry as well as manufacturing and metallurgical industries. It is believed that these measures will ensure that the finances of the Institute are placed on a firm foundation on which the expanding activities can be planned. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of R73 and the total fund was, therefore, increased by this amount to R4 411. The balance sheet shows that the market value of quoted shares and debentures increased during the year fron R6 540 to R9 160. The market value is now almost exactly the same as the book value. Accumulated funds now amount to R23 010 compared with R17 959 a year ago.

A Colloquium and General Meeting were held on 17th March 1971, the theme being 'Future trends in steel production'. Mr V. C. Robinson (President) was in the Chair. The Colloquium was attended by 121 delegates and was opened by the President at 10 a.m. OBITUARIES THE PRESIDENT: 'It is my sad duty to announce the death of the following: F. O. Read, Fellow, who joined the Institute in 1957 and passed away on 13th January, 1971. P. G. M. May, Member, who joined the Institute in 1969 and passed away on 10th August, 1970. R. J. J. Rademeyer, Life Fellow, who joined the Institute in 1942 and passed away on 23rd September, 1970. As a mark of respect to the memory of the deceased and in sympathy with the bereaved I would ask you all to rise and observe a few moments silence. CONFIRMATION OF MINUTES THE PRESIDENT: 'May we confirm the minutes of the monthly general meeting held on 21st October and 18th November, 1970, as published in the Journal'. Agreed. MEMBERSHIP THE PRESIDENT: 'I have much pleasure in announcing that the names of the undermentioned candidates, having been published in accordance with ByLaw 5.2.2, Council has elected them to membership of the Institute in the following grades: FELLOWS: Romain August Lathioor, Paolo Piga, Renato Ribacchi, Willem Frederick Jacobus Smith, Matthew Churchill, Thomas Anthony James Braithwaite, Hugh Patrick Hart, Eleanor Innocentius Muller, David Alton Smith. MEMBERS: Douglas Adendorff, Petrus Jacob du Plooy, James Valentine Grant Middleton, Karl Anders Ullerstam, Josephus Theodorus Johannes van Wyk, Frank Douglas Abbott. GRADUATES: David Mervyn Gilbart-Smith, John Philip Wilcocks Bennie, Hendrik Theunis Burger, Johann Wilhelm Coetzee, Johannes Stephanus StOols, Leon van Tonder, Brian George Harvey, John Kennedy McLean. ASSOCIATES Richard Cyril Lee Stoyell, Terrence Brian Gouws, Alister Rodney Frederick MacDonald. STUDENTS: Andries Groenewald, Christiaan Johannes Hattingh, William Hendrik Hofmeyr, Stanley Thomas Vincent. I welcome the new members to the Institute and congratulate them on their election. COLLOQUIUM The President welcomed everyone present and mentioned that this was the first of the Colloquia which are to replace the Institute's monthly meetings. He stressed that discussion at Colloquia would be completely informal and would not be recorded unless the contributor requested publication. In conclusion, he thanked the organising committee, the authors and the contributors, and introduced the author of the first paper. The following papers were presented:- 'The future development of the Iron and Steel Industry' by J. P. Coetzee (Published in the Journal March 1971). Among those who contributed to the paper were Dr Bleloch, Dr K. Gebhard, Dr Way and Professor Müller. The main point made by Dr Bleloch related to the reserves of coking coal and of coal for power generation this in country and he deduced that in South Africa we are critically short of coking coal. On the basis that 4 million tons per year of coking coal are consumed for our present steel production, over 16 million tons would be required to meet the anticipated expansion in steel output by A.D. 2000. This must be set against the grim forecast made by the Coal Advisory Board in 1967 that our national reserves of coking coal will be exhausted before A.D. 2000. This gives tremendous significance to the development work presently being carried out by Iscor on alternative methods for coke production. On the other hand the blast furnace may have to be replaced by an alternative process for the reduction of iron ores, e.g., the use of rotary kilns followed by electric arc smelting. Dr Bleloch also expressed grave forebodings about the reserves of bituminous coal, pointing out that with present methods of mining the recoverable coal in any given reserve is in general only 50 per cent of that reserve. He stated that in the past seventy years great quantities of coal have been forever placed beyond the reach of mining by being undermined by extraction of lower seams or lost by being burned. A final point made by Dr Bleloch was the fast rise in the capital investment in a fully integrated steel plant, the figure having risen in the past decade from just over R200 to R350 per ton of finished steel per annum. Dr Gebhard spoke of the direct reduction processes for iron making pointing out the difficulties of securing a high percentage of reduction and the relatively high cost of smelting in electric arc furnaces. As an alternative he suggested briquetting the high carbon sponge iron

By R. R. M. Cousens, W. S. Garrett

Discussion: L. T. Campbell Pitt: When Mr Garrett and I discussed the design and construction of plugs and bulk head doors to resist great water pressures in mines about ten years ago, we visualized an emeregeny when there would be no time for site preparation. We could not however, anticipate a problem of such magnitude and urgency as the one described in the paper under discussion. The paper very clearly describes the flooding and the measures taken to save the mine. The complete flooding would have been a national disaster. The account of the combat between man and water reads like the account of a military operation. It was an endeavour which achieved success because there was a master plan, tenacity and, in fact, heroism. The paper is of necessity a long one. In my contribution I will mention some historical facts and factors that I believe have relevance to the flooding and the saving of the mine. It is of great satisfaction to me to have been one of the two initiators of a new approach to underground plug design and construction. The investigation was taken over by a Chamber of Mines Committee which combined our early work with further research and the resulting data had a significant bearing on the West Drie emergency plug designs. The final plug length was correctly based on the requirements to obviate leakage. A plug to have structural strength only would have been very much shorter but so ineffective as to have become a waste of labour, material, and in consequence, wasted the limited time available to prevent flooding of the whole mine. The figure of 75 lb per sq in. sheer stress provided a very ample margin, in my opinion, but under the very difficult site conditions and the limitations of plug material suitable for the very unusual construction, justified such a figure. There must have been considerable temptation to reduce the safety margin due to the urgency to complete and commission the plugs, but it is much to the credit of the directors of this operation that nothing less than a safe design was permitted. In about 1945 Blyvooruitzicht Gold Mining Company, which was then mining in to the West Driefontein area to assist in early development, decided to protect themselves from a possible inrush of water from the latter mine. A bulk head door was accordingly designed and installed on 2 level between 1945 and 1948 at 4,218 ft below surface. Since West Driefontein paid for it, Gold Fields consulting mechanical engineers collaborated with their colleagues of Rand Mines who completed their design after a few modifications were agreed. This door was never used to prevent an inrush into Blyvooruitzicht but the exercise was very useful to Gold Fields when the high pressure doors initially installed on 10 and 12 levels between Nos. 2 and 3 shafts to enable isolation of one section of the mine from another were designed. At that time the capacity of West Driefontein to cope with an inrush of water was comparatively small because the storage in stoped areas and the installed pump capacity were much less than in later years. These doors together with others of the same design were later moved to the lower levels served by sub vertical shafts. In addition, doors to prevent flood water entering the pump chambers on 18 level were installed at each end of that level, and designed for a head of 360 feet so that water would have to reach 16 level before the pumps were flooded. All these doors were called upon to hold water and it is reported that only a small plug in one of the doors and a 4 in. dia flanged pipe joint failed. The lesson is that in these cases the smallest details warrant as much attention as the major ones. That these were the only equipment failures when so much depended on equipment, is very much to the credit of design engineers, both of the Gold Fields head office and companies who supplied both mechanical and electrical equipment. Until I had read the paper I wondered why the policy of isolation by bulk head doors was not continued as the development moved eastward towards the Bank Compartment and particularly when it pierced the Bank dyke. The reasons have been given in the paper. It was unreasonable to expect provisions to be made to counter the remote contingency that the large installed pumping capacity and mine capacity to store water would be exceeded during a peak inrush. When pumps were being considered for West Driefontein, it was decided that the Gold Fields standard underground main pumps at that time of 1 million gallons per 24 hours would be too small. Three alternatives were considered. 1. Very large units that would require underground sub assembly and dismantling of both pump and motor. 2. The largest pump and motor that could be conveyed as a complete pump or motor from surface to the pump chamber. 3. Pumps of higher speed to reduce dimensions and weight. It was decided to adopt alternate 2 because of avoidance of transporting pumps in parts and assembling underground. Alternative 3 was not favoured because high speeds would have introduced problems of more exact rotor balancing. I believe the decision was correct and in the crisis enabled comparative easy transport of pumps and motors to surface for overhaul and, if required, transfer to other pump stations. The standard pump thus became a 10 stage 1,500 rpm pump with a capacity of approximately 2 million gallons per 24 hours against a static head that varied

Jan 3, 1969

"I have been involved in the refractory industry for many years and at some time or another I have designed materials, tested materials, manufactured materials, installed materials, in fact I have done everything except actually chemically analyzed a refractory material.So I would not even begin to tell you how to analyse a refractory material. I'm sure everyone here knows more about chemical analysis than I do.However you could regard me as a customer with and perhaps the insights I have developed may help in putting the role of chemical analysis in the Refractories into perspective.For a start, let's take a step back and ask why we test refractories. The refractories handbook of the American Foundry Association gives four reasons:1. To determine appropriate specification.2. For quality control, to ensure conformance to specifications.3. To provide special property information not available elsewhere.4. For postmortem analysis to determine property changes in service and provideinformation that can point the way to better service.I want to discuss these points with regard to the role of chemical analysis and in particular the abuse of in house chemical analysis facilities. Let me talk first about detelmining appropriate specifications. Most refractory products are made from alumino-silicate raw materials.The phase diagram for alumino and silica is as follows:"

Jan 1, 2014

The November General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 18th November, 1970, at 4.00 p.m. V. C. Robinson (President) was in the Chair. There were also present 30 Fellows, including J. K. E. Douglas, R. C. J. Goode, Dr J. P. Hugo, Prof J. de V. Lambrechts, D. G. Maxwell, Prof R. P. Plewman, Dr M. D. G. Salamon, P. W. J. van Rensburg, L. W. P. van den Bosch (Council Members), R. E. Burnton, S. Craib, D. de Villiers Oxford, J. C. Fritz, G. W. Gray, G. H. Henderson, S. D. Hill, C. H. Kruger, B. Leach, C. S. MacPhail, D. J. Molony, W. G. Fyne Mercier, R. A. Scott, M. v. R. Steyn, I. E. van Aswegan, A. D. Vos, J. M. Vosloo and N. Zolezzi. Four Members, including I. G. Evans, R. W. Shearer, W. Wilson. One Associate: P. M. C. Wilson. Four Students: H. G. Albertyn, J. T. Davies, P. G. Henderson and P. J. Pretorius. Fourteen Visitors, including S. R. Barker, F. H. Deist, Dr de Jager, L. F. Duvel, P. du P. Kruger, B. D. Maree, B. R. Meyer, R. Redmond, J. Rietief, A. W. S. Schumann, Mrs A. W. S. Schumann, T. S. Stoffberg, C. A. Visser and R. van der Wait. Secretary, D. C. Visser. Total present 55. The President: "Gentlemen, I would like to welcome all members of the Institute who are present, and visitors, and I would like specially to welcome any members of the Suid-Afrikaanse Akademie who are present this afternoon." OBITUARIES The President: "Before starting on the agenda the first item, of course, is unfortunately obituaries and it is my sad duty to announce the death of the following: I would like to start with a person who is not actually a member of the Institute but who, in his capacity as President of the Chamber of Mines, was Honorary President of this Institute three times and I refer, of course, to Mr Herman Calderwood Koch who passed away last Saturday. Then I would refer to Richard Beaumont Tasker, Life Fellow, who joined this Institute in 1932, and who died on the 22nd of October, 1970. Then, lastly, Mr Jean Francois du Plessis, a student, who joined the Institute on the 19th June, 1968, and passed away on the 11th of November, 1970, as the result of an accident. Mr du Plessis was to have received a Student Prize today for his paper entitled, Displacements and stresses in the vicinity of a horizontal long-wall'. We were all most upset to learn of his death last week, and we are now going to make arrangements to hand his prize to his widow on a suitable special occasion. As a mark of respect to the memory of the deceased, and in sympathy with the bereaved, I would ask you all to stand and observe a few moments' silence. Thank you." CONFIRMATION OF MINUTES The President: "May we confirm the minutes of the monthly general meeting which was held on 16th September, 1970, as published in the November Journal?" Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute in the following grades: Fellow: Ronald White Ballantine. Members: Jan Johannes Hertzog Viljoen, Agge Petrus Rutgerus van der Meer, Peter Anthony Reynolds, Ernest Esdaile Leyde Hans Lutz Klingmann, Ronald Archer.' Graduates: Trevor Stanley Schultz, Thomas Cochrane Meiklejohn, Leslie Harold Heyman, Dennis William Bosch, Sydney Stuart Absolom. Associates:Roderick James.Vermaak, Theodorus Daniel van Wyk, Michael Osmond Savignac Stedman, Leslie Owen Raymer, Bryan Arthur McKay, Leon Ellis Finlay Leask, Dudley Graham Lovedren Hall, John Arthur Gibbon, Richard Reginald de Villiers, Carel Frederik Boshoff. Students: Frederik Wilhelm Christian Coetzer, Phillippus Johannes de Wit, Jan van der Merwe Grimes, Davood Khareghani, Jan Wolvaardt Oberholzer, Johannes Lodewikus Pretorius Pieter Jacobus Strobos, Herbert Gerald Waldeck.' MEMBERS TRANSFERRED TO A HIGHER GRADE From Associate to Fellow: Howard Mitchell Wells. From Associate to Member: Ernest John Dominy. "I welcome the newly elected members to the Institute and congratulate the members who have been transferred to a higher grade." AWARDS The President: "It is with very great pleasure that I can announce that Council has agreed to make the following awards for papers presented to the Institute during the year ended July, 1970. Gold Medals to Prof Plewman and W. D. Ortlepp for their paper entitled 'The development and application of a digital computer method for the solution of strata control problems' written jointly with F. H. Deist (Visitor) and presented in September, 1969. A Silver Medal to Dr Finkelstein for his paper entitled 'The Influence of sulphydryl and cationic flotation reagents on cyanidation of native gold' written jointly with Dr K. G. Ashurst (Visitor), and presented in June 1969 at the Symposium on the Recovery of Pyrite. ' May I congratulate these gentlemen on the high honour they have won with their papers. As new medals are in the process of being designed the actual awards will be made at a later date to be announced to members.

By S. M. Graham, G. Mellis

"The determination of the oxidation state(s) of an element present in a solid sample may be required for a number of reasons, including the assessment of the degree of reduction which has taken place during a multi-step production of a metal. In addition, possible flaws in a metal may result from small amounts of oxides included in the solid. The analyte of interest may be present as a major component of a sample of interest, or as a minor impurity - beneficial or requiring removal - in another matrix.Numerous methods have been established for the analysis of species in solution samples - for example, Fe2+ and Fe3+ by titration, Cr6+ by colourimetric means, etc. With appropriate knowledge of the solution being analysed, many of these methods are fairly straightforward, extremely reproducible and accurate. In those instances where the analyte in a solution is known to be in only one form, the analysis is even more straightforward, since it can be achieved instrumentally (by AAS, rCP-OES or rCP-MS, for example).However, the situation with respect to the analysis of solids is not as simple. Various techniques - such as X-ray diffraction - are routinely used by our mineralogists to obtain information about the various minerals present in solid samples, and thus about the oxidation states of the analyte elements present. However, these techniques usually give results that are qualitative, or semi-quantitative at best. They are also usually time-consuming and expensive. One of our colleagues at Mintek, Deshenthree Chetty, has done extensive work in developing a method for the quantification of manganese species in solids using mineralogical methods, and this is no small achievement."

Jan 1, 2014

By N. Hanief

This research involves the investigation of phase transformations in the platinum-chromium coated system. Single-layer 0.1 µm platinum coatings were deposited via electron beam deposition on 99.98 percent pure chromium substrates. Specimens were subjected to systematic heat treatment in a vacuum furnace at 900°C for up to 20 hours. Phase formation and the changes in surface morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Both CrPt and Cr3Pt phases are formed during heat treatment for different times at 900°C. Significant changes in the morphology of this coated system were detected after heat treatment at 900°C for 20 hours.

Jan 1, 2012

By H. Brüggemann

The exploration of deposits generates geological data which are suitable for creating a preliminary tectonic and stratigraphic model. Linked with the topographical map and analysis data from exploration drillings, this information forms a numeric representation of the deposit. The following example demonstrates an expert system which connects chemical quality requirements and quarrying criteria, and develops a quarrying strategy based on the calculated model. Additional constraining factors like process technology, quarrying methods, landscape protection regulations, etc. are included. The goal is to guarantee a long-term, homogeneous material flow from the quarry at acceptable production costs - even in the case of an extraordinarily inhomogeneous deposit. In order to fulfil this requirement it is necessary to consider a large number of rules, criteria and instructions which can be structured as an expert system and programmed with LISP at a comparably low cost. The chosen strategy is not necessarily final, but can be changed any time by altering or varying the framework of conditions. The output consists of a block-working sequence which best satisfies the set requirements for appropriate points of quarry opening.

Jan 1, 1987