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By C. Chapman, M. G. Reading, M. P. Amsden

Computer control of flotation at the Ecstall concentrator By M. P. AMSDEN, C. CHAPMAN, and M. G. READING Ecstall Mining Limited, a subsidiary of Texas Gulf Sulphur Company, operates the Kidd Creek Mine, a 10000 tons per day base metal producer, near Timmins, Ontario. Two different types of ore are mined and milled: copper-zinc and silver-lead-zinc. At the highly automated Ecstall concentrator the ores are processed by selective flotation in three individual circuits. One of the most important metallurgical tools for process control is a sample system incorporating continuous on-stream X-ray analysis. Recently this system was automated further by the addition of computer control of reagents for two copper-zinc flotation circuits. The computer programs, utilizing optimum seeking methods and smelter contract terms, have increased copper recovery by 1,1 per cent, zinc recovery by 1,4 per cent, and have reduced reagent costs by 16 per cent. Although not expected, copper and zinc concentrate grades were improved slightly as well.

By Y. Wang

Arsenic-bearing acidic effluent from hydrometallurgical processes contains many harmful metal ions and must be appropriately treated before discharge. In the present study, arsenic, copper, zinc, aluminum, and magnesium were co-precipitated by means of the Fenton reaction. The precipitates obtained under different conditions were investigated to determine their stability. The results indicate that pH value and hydrogen peroxide (H2O2) dosage have significant effects on the removal of various elements. Arsenic, copper, zinc, and aluminum (but not magnesium) can be removed at pH 5–6 and anH2O2/As mole ratio of 2 at ambient temperature. The precipitates were mainly amorphous and granular with particle size in the micrometre range. The arsenic concentration in leachate from the toxicity characteristic leaching test was 3.6 mg/L, which proves that the precipitates are effective in fixing arsenic.

Aug 3, 2023

By T. Scheldt, M. Lu, A. Myrvang

Abstract: In this paper both continuous and discontinuous modelling are utilised in order to analyze the stability of the Gjøvik Olympic Mountain Hall. The large span cavern (62 m) was built for the 1994 Winter Olympic Games at Lillehammer, and is a unique case study because of the large amount of available input data, through a comprehensive pre-investigation, stress and deformation monitoring program before, during and after the excavation. Phase2, a two-dimensional non-linear finite element program, and the Discontinuous Deformation Analysis (DDA) are used as representative tools for continuous and discontinuous modelling, respectively. The analysis results are compared and discussed taking the reliability of the models, time-consumption and costs into consideration. Some guidelines for the total modelling process, from field measurements to final results, are also presented. Zusammenfassung: In diesem Artikel werden sowohl kontinuierlich als auch diskontinuierlich Modellierung verwendet, um die Stabilität, der in den Berg gebauten Olympiahalle in Gjøvik zu analysieren. Die Olympiahalle wurde 1994 zu den Olympische Spielen in Lillehammer errichtet. Ihr Dach erstreckt sich über eine Breite von zweiundsechzig Meter. Für den Bau wurden umfangreiche Daten durch Voruntersuchungen, und Überwachung von Gebirgsspannungen und Deformationen bevor, während und nach Exkavation eingesammelt. Auf Grund dieser großen Datenmenge stellt die Olympiahalle ein herausragendes Beispiel für den Bau ähnlicher Projekte dar. Für die kontinuierlichen Modellierungen wurde „Phase2“, ein zwei-dimensionales, nicht lineares „endlich Element“ Rechnerprogramm angewandt. Die diskontinuierlichen Modellierungen erstellte man mit Hilfe von der „Diskontinuierliche Deformations Analyse“ (DDA). Die Analysenergebnisse sind mit Rücksicht auf die Zuverlässigkeit der Modelle, Zeitverbrauch und Kosten verglichen und diskutiert worden. Im Artikel werden Richtlinien für den Modellierungsprozess von Dateneinsammlung bis Schlussfolgerung gegeben. Résumé: Dans cet article la modélisation continue et discontinue sont utilisés pour analyser la stabilité de Gjøvik Olympic Mountain Hall. Cette caverne de grande portée (62 m) a été construite pour les Jeux Olympiques d’Hiver de 1994 à Lillehammer, et est une étude de cas unique grâce à la grande quantité de données disponibles, de par un programme de pré-investigation compréhensive, monitorage des contraintes et déformations avant, pendant et après l'excavation. Phase2, un code d’éléments finis non linéaire à deux dimensions, et l’Analyse en Déformations Discontinues (DDA) sont utilisés comme outils représentatifs de la modélisation continue et discontinue, respectivement. Les résultats d'analyses sont comparés et sont discutés, prenant en compte la fiabilité des modèles, la consommation en temps de calcul et les coûts. Quelques indications pour le procédé total de modélisation, des mesures sur place aux résultats finaux, sont aussi présentées.

Jan 1, 2003

By D. D. Howat

In the field of high temperature smelting processes there have been two dramatic changes in the past twenty years. These are, first, the application of tonnage oxygen for direct injection for the refining of molten iron and other metals and to provide the means of enriching air used for the combustion of fuel. Second, the application of electric power for the generation of high temperatures in place of the combustion of fossil fuels. Of these two developments the application of tonnage oxygen for the refining of molten iron has virtually revolutionised the steel industry throughout the world. The magnitude of this development is exemplified by the fact that less than 5 per cent of the world's steel production in 1960 was made by this process or 16 million tons out of a total of 350 million tons of steel produced, while in 1970 over 40 per cent of the world steel production was made by this process, ie, 251 million tons out of 628 million tons total. In the same period the proportion of steel produced by the old-established open-hearth process has shrunk from 75 per cent to 38 per cent. In the whole history of the development of high temperature metallurgical smelting processes there has never been anything remotely approaching this. The other development, the application of electric power for the generation of high temperatures has not had the impact of the oxygen injection process but I believe that what we should call the electric smelting revolution in metallurgical processes has very far-reaching ramifications for steel production and other pyrometallurgical processes. This may seem a bold and brash statement but it must be remembered that the oxygen injection process constitutes a link in the chain critically dependent upon the production of vast tonnages of molten iron from very large modern blast furnaces. The Achilles heel of this chain of processes, upon which such a large percentage of the world's supply of steel depends, is the availability of metallurgical coke in turn dependent on natural resources of coking coal. Without any exception each industrial country in the world faces a shortage of resources of coking coal and in some cases a critical shortage. Certainly within the present century the major iron and steel producing countries of the world will face this critical shortage of coking coal and major modifications to steel making processes will become inevitable. W. F. Cartwright (Deputy Chairman of B.S.C) said recently that there are considerable doubts as to whether the world will be able to provide enough coking coal to meet world steel demands from the late 1970's onwards if the B.F.remains the main means for making iron from ore. This is one of the supreme ironies of the world metallurgical situation to-day when the technology of iron and steel production has reached an extremely high peak of technical efficiency. The newest modern iron blast furnace capable of producing 6 000 to 8 000 tons per day of molten iron represents probably the most efficient piece of high temperature metallurgical plant and operation known to man. The conversion of this molten iron into steel by the oxygen injection process has made available to the engineering industry steel of a quality and at a price which is quite remarkable. Yet this vast metallurgical pyramid rests on the completely insecure and uncertain foundation of inadequate world resources of coking coal. The shortage of reserves of coking coal in this country is acute and it is possible that these resources will be exhausted within the next twenty years. Yet unless some completely unexpected catastrophe occurs the demand for steel in this country will probably rise at a faster rate than in the Western world due to the expansion of the Bantu population and the increased standard of living. To offset the inevitable shortage of coking coal are our much greater resources of bituminous coal which although of low grade provide a suitable fuel for electric power generation. The geographical disposition of the coal fields in relation to the great industrial areas of the Transvaal makes it inevitable that the development of the pyrometallurgical industries must depend heavily on electric power. The position in this country with regard to electrical power generation and consumption is rather anomalous. Per capita consumption of electric power is high - in 1964 almost twice the world average of 870 KWH and twenty-five times the average of 34 KWH for the Continent of Africa. In 1964 fifty-four per cent of the total world electric power was used in industry - the ratio being approximately 1/9 mining to manufacturing uses. As shown in Table I in 1969 67.2 per cent of the total output of electric power from ESCOM was used for mining and other industrial uses but almost in the ratio 6/4 mining to industrial uses. These figures emphasise the enormous importance of the mining industry to the economy of this country and underline the major contribution made by the gold mining industry. What is of very significant importance is that although the mining industry remains by far the largest single consumer of electrical power the consumption of power for industrial uses is rising rapidly as shown in Table II.

A powerful, interactive metallurgical process simulator for use on micro- computers has been developed in the Department of Metallurgy and Materials Engineering at the University of the Witwatersrand. MICROSIM presently allows simulation of all ore-dressing flowsheets and a selection of hydrometallurgical unit operations, and is extendable to all such processes. MICROSIM is written in Pascal. This modern language provides very versatile data structures which can be effectively used to solve the major problem in generalised simulation programs, namely storage and transmission of data relating to liquid and solid phases. Dynamic memory allocation allows optimal utilisation of computer storage space. The simulator utilises very efficient precalculation algorithms that determine the tear streams for optimal sequential modulator calculation convergence. Microcomputer graphics simplifies flowsheet specification, and form-filling data capture with supplied default values eliminate most common input errors.

Jan 1, 1987

By R. C. Nkhoma, K. A. Annan, S. Ngomane

The effects of welding current, electrode force, and welding time in a resistance spot weld were studied to investigate the effectiveness of welded joints between a thin EN10130: DC04 material and a thicker 817M40 part, through analysis of the microstructural and mechanical properties. All welded specimens were subjected to tensile testing at room temperature (25°C) and sub-zero temperature (–46°C) to test the strength of the welded joints. No full button failure was observed at either room temperature or sub-zero temperature after optimization of the weldng parameters. The fusion zone was observed to consist mainly of martensitic phase, due to rapid quenching, while the HAZ was composed of clusters of martensite in a ferrite and bainite matrix. The base 817M40 metal remained fully ferritic after welding. The hardness was found to increase with increasing welding current. An increase in nugget size, indicating good fusion of the weld, was observed with an increase in the welding current.

Oct 1, 2021

By C. O’Donova, E. Adam, L. A. Torres-Cruz

High-profile failures of tailings dams illustrate the significant safety challenge they pose. The decant pond of such facilities plays an important role in their mechanical stability. This study investigates the feasibility of using public multispectral data collected by the Sentinel-2 satellite mission to monitor the area of the decant pond. The Sentinel-2 mission has a revisit time of 5 days and the data used herein has a spatial resolution of 10 m/pixel. We considered two water-detection metrics: the normalized difference water index (NDWI) and the near-infrared (NIR) reflectance. Implementation of the method at a South African platinum tailings dam illustrates the capabilities and limitations. Public, sub-metre resolution true-colour imagery served as validation data. There is good agreement between pond area measurements based on Sentinel-2 and the validation imagery. These results suggest the feasibility of using Sentinel-2 data to supplement the monitoring of the decant pond.

Apr 2, 2022

By J. D. T. Steyl, G. B. Grobbelaar

Two examples are presented to show how first-principles – physical-dynamic, here termed behavioural modelling, is used to build digital twins of unit processes or plant sections. A digital twin equips the metallurgist, engineer, or manager with a powerful tool to conduct model-based design, solve process problems and improve operations. It is particularly relevant in the metallurgical industry where plant behaviour is highly integrated, rates respond to particle dynamics in complicated ways and mineral flows across flowsheet boundaries are variable. The two examples used to illustrate the behavioural modelling methodology are 1) a flotation column unit block and 2) a multi-compartment pressure oxidation (POX) autoclave. It simultaneously accounts for the causality of material and heat flow, takes care of mineral particle dynamics, physical and chemical reaction rates, the plant control system behaviour and operating heuristics. The basic modelling building blocks are briefly reviewed to show how the behavioural modelling attributes constrain the mass and heat flow dynamics to physically realistic values. This is the key aspect that allows project value to be created with minimal input data. Behavioural modelling is especially valuable where the process dynamics are poorly understood or controlled, where data-driven models fail to cope with complex and highly integrated plant behaviour, where quality data is lacking or limited funds are available to generate the data required to fill all the knowledge gaps. The paper uses the flotation column example to show how behavioural modelling and simulation can be used to optimise plant performance, while the multi-compartment POX autoclave model shows how it can be used to diagnose process problems. It also provides a solid basis to add a data-driven component – in other words, it makes a strong case for a hybrid first-principle– data-driven approach to solve process problems, especially where microscopic-level understanding is poor. Keywords: Digital twin, behavioural modelling, simulation, flotation column, pressure oxidation

Jan 1, 2020

By J. R. Dixon

Gold mining has been undertaken in South Africa for more than a century. A great proportion of that mining has been from the Witwatersrand Basin; a geological phenomenon that has few parallels throughout the world. It has produced some 47 000 tonnes of gold mainly from underground mines, many of which have been truly world class gold mines. The gold mines of the Witwatersrand Basin have dominated world gold production from their inception and their production has been one of the cornerstones of the development of South Africa as a whole. The mines have some very specific characteristics; their sheer size, the depth of extraction, the nature of the orebodies, and their labour-intensive methods. The mines have also been part of the Mining House concept-a concept unique to South Africa. South African production has declined from a maximum of 1000 tonnes in 1970 to 470 tonnes in 1997. This, as a percentage of western world production, has declined from a maximum of 79 per cent (in 1970) to 21 per cent of world production (in 1997). The nineties' have seen South Africa and its mining companies move onto the world stage and face the harsh realities of having to compete in all spheres of business with their aggressive counterparts principally in Australia, Canada and the USA. The fight is for investment funds with the owners looking for the best returns on their money. In his address Roger Dixon will examine the current situation in the gold mining industry and examine the competitiveness of the mines of the Witwatersrand Basin compared with their peers worldwide. He will also discuss some of the fundamental challenges facing South African gold mines in the areas of legislation, technology, industrial relations, and health and safety. The environment in which the mines operate has changed radically in recent years and their ability to respond to these challenges will determine their future existence.

Jan 1, 1998

By M. Rudolph, A. D. Renno, H. Wu

In this study, synthetic pure cassiterite and cassiterite doped with Fe were successfully produced by sintering. Their crystal structure and chemical compositions are characterised by optical microscopy, X-ray powder diffraction (XRD) as well as scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) based chemical composition analysis. The electrostatic behaviour of synthetic and natural cassiterite was studied by electrophoretic measurements. Their floatability was studied by microflotation with two types of anionic collectors. Results show that the cassiterite floatability with these collectors behaves differently and lead to two opposite results: Natural cassiterite (enriched with Fe) > undoped pure SnO2 by using sulfosuccinamate (Aerosol® 22) Undoped pure SnO2 > Fe3+ doped > natural cassiterite (enriched with Fe) by using styrene phosphonic acid (SPA). Keywords: Synthetic cassiterite, lattice impurities, flotation, zeta potential, Aerosol® 22, styrene phosphonic acid

Jan 1, 2020

By R. Pretorius, N. Mautsa

In a cobalt precipitation plant, phosphoric acid is used to eliminate excess uranium from the pregnant leach solution, resulting in a cobalt hydroxide product that has little uranium contamination. However, the amount of phosphoric acid added must be monitored and controlled to avoid financial and sustainability impacts and to prevent negative impacts on the final product quality. One possible solution to this problem is the use of online residual phosphorus measurement techniques to regulate the addition. By continuously monitoring the residual phosphorus levels in the solution, the plant can adjust dosing in real time to maintain the target residual phosphorus level. As a result, the cobalt precipitation plant can improve phosphorus level control, lowering the risk of overdosing, and ensuring consistent product quality. This approach can also improve process efficiency, reduce operational costs, and have a positive environmental impact

Jan 1, 2023

A General Meeting and Colloquium was held in Kelvin House, Johannesburg on Wednesday 29th September, 1971. The theme of the Colloquium was "The Ferro-alloy Industry". Prof D. D. Howat (President) was in the Chair. The meeting was attended by 106 delegates and was opened by the President at 10.05 a.m. OBITUARY The President: "It is my sad duty to announce the death of G. C. Needham, Fellow, who joined the Institute in 1966 and passed away on 27th September, 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." MEMBERSHIP The President: "I have much pleasure in announcing that the names of the following candidates, having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute. Fellows: Richard Lloyd Blandy, Brian Roger Borton, Brian Teversham, Peter Donald Dickson. Members: Frederick Brian Peacock, Peter John Stacey, Kenneth Niles Thanstrom, Byron J. Hayley, Ian Flemming Buchan, Abraham Hercules le Roux. Graduate: Ian William Coy. Students: Peter Boesley J ames, Kenneth Brian Perel. TRANSFERS From Member to Fellow: Cecil Eugene Fivaz, Peter Edwards. From Student to Graduate: Roy Stavely Traviss. From Student to associate: William Mitchell. I welcome the new members to the Institute and congratulate those members who have been transferred to a higher grade. COLLOQUIUM The first paper, presented by Mr S. Selmer-Olsen, Consulting Metallurgist, Amcor Limited, on 'Trends in Ferro Alloy Production' was published in the May issue of the Journal and comprised information and data relating to new developments in ferro alloy production in various parts of the world. This was followed by a paper-'Conductivity and Viscosity Properties of Slags produced in ferro-alloy manufacture' by D. 1. Ossin et al. This was a record of laboratory test work on slags containing both lime and magnesia, corresponding with the composition of slags encountered in the production of ferro chrome alloys when a dolomite flux is employed. The third paper-'Review of the work of the Pyrometallurgical Research Group of N.I.M. and Metallurgy Department, Wits.' presented by Dr P. R. Jochens, leader of the Research Group, outlined the progress made on ten different research projects presently under way in the Department of Metallurgy. These projects range from studies of the kinetics and mechanism of the reduction of chromite ores through the determination of the activities of MnO in slags to phase studies and melting point determinations in the alloy systems Cr-Fe-Si-C and Cr-Fe-Si. A new feature of this Colloquium was the introduction of the discussion panel composed of four or five individuals known to have special knowledge or interest in the subject under duscussion. Mr J. J. Coetzee was chairman of the first panel, Professor D. D. Howat of the second and Dr R. E. Robinson of the third. During the discussion of Mr Selmer-Olsen's paper an interesting contribution was made by Mr Jack Hayley of Transalloys (Pty.) Limited who pointed out that the lowest power cost in the U.S.A. was that from the TV A at 6 mils per unit (0,43 cents S.A.) while costs from other sources were 7 to 8 mils per unit (0,50 to 0,57 cents S.A.) He also referred to the use of 'pile sintering' of ore fines plus coke at certain ferro alloy plants in the V.S. and to the recent practice of 'graphitising' the paste used for Soderberg electrodes. The last session in the afternoon was devoted to a group discussion on 'Practical problems in Arc Furnace Operation', Mr H. R. Reid of Middelburg Steel Alloys (Pty) Limited occupying the chair, members of the panel being Mr J. Meintjies (Rand Carbide Limited), Mr J. Benn (Amcor) and Mr E. J. Jackson (Transalloys (Pty.) Limited). Mr Reid initiated the discussion by talking of the design and composition of electrode shoes, mentioning the use of the 85/15 Cu/Zn alloy and the comparison of hollow shoes and shoes cooled by tubes. Mr Meintjies discussed electrode management with particular reference to breakages, and dealt with casing and fin design and the welding of fins. Mr Benn dealt with aspects of closed top furnace operation with particular reference to the control of eruptions in the furnace and indicated that preheating of the raw materials might be well worth considering together with the development of a system for the detection of the water vapour present. Mr J ackson was concerned with shells, linings, refractories and tap holes. He deprecated the use of oxygen for opening the tap hole emphasising how uncontrolled use of oxygen led to loss of shape of the tap hole and quite severe burning out of the front hole resulting in time and labour in repairs. A notable feature of the Colloquium was the free discussion 'from the floor' of the hall. Many valuable and highly pertinent contributions were made spontaneously and usually in reply to some controversial topic raised by the discussion group.

By H. Matsuoka, M. Kawata, K. Mitsuhashi, C. Tokoro, T. Kato

Copper sulfide minerals generally have high floatability, but their floatability decreases when surfaces are oxidised under some conditions. Sodium hydrosulfide, NaHS, is known both as an activator and as a depressant for copper minerals. NaHS at low concentrations activates copper oxides by sulfurising surfaces, but at high concentrations depresses copper sulfides by interfering with the adsorption of collectors. In this paper, we applied NaHS to activate oxidised chalcocite and bornite and focused on the conditions of NaHS treatments such as dosages and pH, and the effect of these conditions on the floatability of those minerals. The pure minerals treated with NaHS were analysed using zeta potential analyser and X-ray photoelectron spectroscopy. Analyses indicated that the reactions of NaHS and the products on the mineral surfaces after the reactions (i.e. oxidation, pH change) depended on whether NaHS reacted with copper or iron, and the reactions between NaHS and iron depend on NaHS concentration and pH. Flotation tests using a small column cell were performed with a single pure mineral, and using a Denver-type flotation machine with a copper sulfide ore. The results of each flotation test were utilised to clarify the floatability. The relation between flotation behaviours and analysis results were also discussed. Keywords: Chalcocite, bornite, NaHS activation, flotation, floatability

Jan 1, 2020

New Journals The following three journals may be of interest to readers: Fuel Processing Technology, Process Economics International, Speculations in Science and Technology, MM reports Report no. 2016 Analysis of the NIMROC reference samples for majorelements. Report no. 2018 Supergene aUeration of sulphide ores. II. The effect on the floatability of chalcopyrite, galena, and sphalerite. Report no. 2013 List of unrestricted NI M publications issued from 1966 to 1979. Report no. 2014 The determination by spark-source mass spectrometry, of chlorine and phosphorus in high-purity tungstic oxide. Report no. 2017 Vanadium-bearing titaniferous iron ores from the Rooiwater, Usushwana, Mambula, Kaffirskraal, and Trompsburg Igneous Complexes. Report no. 2022 The determination of thallium and indium in sulphide concentrates. Report no. 2023 Atomic-absorption spectrophotometry with hydride generation: an improved technique. Proceedings Proceedings of the Eleventh Commonwealth Mining and Metallurgical Congress, Hong Kong, 1978. London, Institution of Mining and Metallurgy, 1979. 800 pp. 35,00 or $U.S.77,00.

Jan 1, 1979

By M. J. Latva-Kokko, CA Snyders, J. R. Peltola, M. K. Kostiainen

It is well known that carbon management is essential for minimising soluble gold losses in carbonin- leach (CIL) and carbon-in-pulp (CIP) circuits. Even so, carbon measurements remain predominantly a manual operation with a low amount of control and automation around CIL and CIP reactors. Carbon inventory, i.e. knowing the carbon concentration in each reactor, is crucial for good carbon management. CarbonSense, a novel in-situ measurement system, was therefore developed for continuous monitoring of the carbon concentration in each reactor and paves the way for more advanced control in gold operations. The carbon management and optimisation system is based on Outotec® HSC Sim dynamic process simulations where each process component is modelled in detail. Generated models are validated with real data from a particular operation. The simulator will allow for the carbon control sequence to be realistically tested and the efficiency optimised by controlling the feed and discharge pumps in a hazard- and risk-free process environment. Furthermore, by combining CarbonSense and Outotec® gold courier (online soluble gold measurements) continuous feed-forward and feedback information can be obtained. The optimiser will then define the best running parameters based on the cost function of gold production versus intrinsic factors such as utility costs and adsorption time. Eventually, the application can be installed parallel with a real process island and it can be continuously calibrated with real-time process data. The dynamic model will then create future predictions for the entire process island. The example case presents a CIL circuit, which is simulated using Outotec® HSC Chemistry Sim and operated through Outotec® ACT (Advanced Control Tool) application. Keywords: Carbon-in-leach, CIL, CarbonSense, carbon management, automated control, simulation

Jan 1, 2020

By C. A. Green, M. A. T. Cocquerel, R. T. Gates

"Engineering studies by Selection Trust, Limited, initially in connection with the development of a copper and nickel deposit for Bamangwato Concessions, Limited, and subsequently for several other clients, have required a large number of metallurgical design calculations. The flash smelting process, developed by Outokumpu Oy in Finland, has been selected as the most suitable method for these projects and the computer programs described in this paper have been developed to facilitate the computation.The data required by the programs arc the chemical and mineralogical analyses of the concentrate, gangue and flux materials and the specification of possible fuels. The required grade of furnace matte is set as the main design parameter and the programs calculate detailed heat and material balances for the smelting process."

Jan 1, 2014

By L. Ozdemir, B. Asbury, T. G. Rozgonyi

A new type of bit, that has been developed and is being evaluated, shows great potential in expanding the range of rock strength that can be cut by continuous miners and roadheaders. This new style of bit is called the frustum. The tools tested in this program were developed, manufactured and patented by Briese Industrial Technologies, Inc. The frustum derives its name from the unique geometric shape of the cutter, or cutting insert. The frustum shape cutting tool has previously been proven as an effective cutting tool for machining metals, metal matrix composites and polymers. The frustum rock bit has a very dense carbide frustum shape tip mounted on the end of a steel body similar to the conical bits typically used on continuous miners and roadheaders. In between the carbide frustum cutting tip and the steel body there can be a bearing that allows the frustum to rotate around the bit axis. When the bit is forced into the rock at a skewed angle, the frustum tip rotates as it travels. This rotation greatly reduces the cutting forces acting on the bit when compared to the current state of the art conical drag bits. This cutting force reduction, derived from the frustum’s cutting action, allows for much harder and more abrasive rock to be cut without quickly wearing out the bit. Full scale laboratory cutting tests have been performed with the frustum bit in direct comparison to the current state of the art conical bits. Field trials of the frustum bit are currently being planned. Test procedures, results and findings are presented.

Sep 1, 2001

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. L. Monro

CONTRIBUTION BY J. R. F. HANDLEY Mr Monro is to be congratulated on his concise treatment of a very complex subject. As a graduate with only Mathematics I in my curriculum, I am unable to comment on the mathematical treatment of the factors affecting his supply/demand model, but the logic does not escape me. The main conclusion is that any excess of supply to the spot gold market will depress the price in a normal market, and particularly in a falling market.

Jan 1, 1993

By K. G. Lomberg

The density used to covert volume to tons is critical in determining the real in-situ tonnage of Mineral Resources. However, the methods used to determine density and the use of different technical terms are seen to be inconsistent throughout the industry. Probably the best discussion addressing the determination of density was presented by Lipton (2001). This paper does not try to replicate this excellent work, but rather to review current industry practice and present a comparison of the approach to density in public reporting. Some of the technical terms used in reporting and the common methods applied are also discussed.

Sep 1, 2021