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By C. C. Pretorius, S. Ramjee, R. J. Mostert

The study investigates the effect of prior corrosive exposure on crack growth resistance behaviour of thin sheet (3 mm thick) aluminium alloy 2024-T3 at slow strain rates. Compact tension specimens were exposed to standard corrosive environments that simulate accelerated atmospheric corrosion attack. Two corrosive environments were considered – an exfoliation corrosion (EXCO) solution and a 3.5 wt% sodium chloride solution. The unloading compliance R-curves of the two-hour EXCO-exposed specimens revealed a significant degradation of approximately 11% in the crack growth resistance behaviour (Kc_e values) compared to the baseline (air-exposed) values. Furthermore, secondary intergranular crack formation was also revealed in the plastic zone ahead of, and adjacent to, the crack tip of these specimens; which formed during the crack growth resistance loading. It is postulated that the observed degradation of the Kc_e values of the EXCO-exposed material is due to hydrogen embrittlement since the exposure times for the EXCO evaluation were limited to ensure that uniform corrosion dominated; that is, significant penetration of corrosion damage and pitting due to localized corrosive attack did not occur. The sodium chloride-exposed specimens revealed a similar degradation (13%) after 24 hours exposure. However, slight intergranular corrosive attack and isolated pitting were observed on the exposed surfaces prior to crack growth resistance loading, resulting in notch effects that could assist in crack growth. Pitting and intergranular corrosion were, however, not observed at the pre-crack tip. The relative contributions of the notch effects and the hydrogen embrittlement during the degradation of the KR performance are, therefore, unclear.

Apr 1, 2021

By H. Xuchun, H. Nailian, L. Guoqing

With the accession to WTO and the establishment of Shanghai Gold Exchange, gold mines in China are facing more severe competition from both home and abroad. Supply Chain Management (SCM), a new management idea gradually accepted all over the world, provides the gold mines in China with a new management mode. In this thesis, under the guidance of SCM theory, based on the analyzing to the actualities of Jiaojia Gold Mine, the Jiaojia supply chain framework is constructed, the function system for Jiaojia SCM is configured, and function modules are described in detail. Keywords: Supply Chain Management, Gold mine, Informatization

Jan 1, 2003

By S. C. Everett, I. S. Schache, P. A. Bannister, G. F. Balderson

The Pooncarie Project is located in the Murray Basin region of Australia. This region is a potential new mineral sands province. Due to the geological environment and the lithology of the deposit, these deposits have some technical challenges that need to be addressed prior to their successful development. Within the Pooncarie Project the Ginkgo deposit will be developed first. The technical challenges it presents include its geographical isolation, the requirement to remove substantial quantities of overburden as well as the processing issues raised by the highly weathered nature of the ilmenite family of minerals. Ore characterization bench scale testwork and bulk sample pilot plant programmes have been carried out and the data obtained used to design flowsheets for both the wet plant and mineral separation plant circuits with the flexibility to enable these plants to handle the variable heavy mineral assemblage. In addition to the solving of the processing challenges, technical issues such as removal of overburden for the minimum unit cost, the use of hyper saline water in the dredge pond and the provision of infrastructure, have had to be addressed. None the less, the orebodies making up the Pooncarie Project have many positive features including low slimes content, good rutile and zircon grades and the ability to recover most of the ilmenite family of minerals into acceptable TiO2pigment feedstocks. The development of the project is set to proceed with the establishment of mining operations on the Ginkgo orebody feeding a mineral separation plant at Broken Hill. The initial shipment of products is expected to occur in early 2005.

Jan 1, 2003

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 S. K. Gilman, P. S. Marcos

There are basic areas of importance within a concentrator or mineral separation plant, which require focus to ensure acceptable recoveries, throughputs remain at an acceptable level and product grades meet specification. Professional and para-professionals within the mineral sands industry are in demand due to the booming resource sector. Added to this, new mineral sands operations are being commissioned straining the industry further. These factors have increased staff turnover and introduced many new people to the industry. It is essential these new entrants are armed with basic plant troubleshooting skills relevant to the minerals sands industry to minimize production lost through poor recoveries. Mineral sands processing does not involve highly technical or sophisticated unit processes. However, success is often slow to arise due to a lack of detailed understanding, as well as managing multiple interrelated unit processes within a plant. Fundamental background physical conditions (such as equipment loading and water quality) must be met for unit processes to be efficient. Technical management of these process plants should always include observation of these background conditions for they often provide the answer to underperformance. Examples are presented with an indication of the possible effects on recovery and product grade.

Jan 1, 2007

O.F.S. Branch Proceedings of the Annual General Meeting Held on Wednesday, 4th August, 1976 Mr G. J. C. Young (Chairman) was in the Chair. Also present was Dr R. E. Robinson, President of the South African Institute of Mining and Metallurgy. NlM reports Report no. 175 Copper extraction by leaching magnetites from Palabora Mining Company. (12th Apr., 1967; re-issued Jun. 1976) Report no. 1632 A mineralogical examination of beach-sand concentrates from a pilot plant at Richards Bay. (20th May, 1974; re-issued Jun. 1976.) Report no. 1825 The full automation of a Philips 1220 X -ray spectrometer. A Philips 1220 X-ray spectrometer (semi-automatic) Report no. 1840 The spectrophotometric determination of total uranium in silicate ores and leach liquors by use of bromo-PADAP. Report no. 1841 The determination of aC1;d-soluble uramum in silicate ores and solutions. AS & TS National Award The Associated Scientific and Technical Societies of South Africa has decided to make two National Awards this year. These awards, given in recognition of outstanding contributions to science and the application of science, will be made to Dr T. L. Wadley for his invention of the Tellurometer system of distance measurement and to Mr H. Scheffel for his design of the High Stability Bogie. Treatment of waste water A major international symposium, organized jointly by the Water and Environment Group of the Society of Chemical Industry and the Environment Group of The Chemical Society of London, will be held in London in 1977. Down-the-hole drilling Atlas Copco announces the publication of a revised and enlarged version of one of the booklets in their series 'Mining and Construction Methods'. This 40-page booklet is entitled 'Down-the-hole drilling with COP drills'.

Jan 10, 1976

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

Dr Hanekom I would like to thank Dr Hanekom for a very valuable -contribution; it summarizes careful statistical test work which was an omission from the original paper. Minor manipulative details, the application of a finer measuring graticule and the reproducibility of the procedure are described and the author accepts with gratitude this ready-made answer to the first and second points of Dr Finkelstein's comments. Mr Williamson The author is indebted to Mr Williamson for historical background to early experiments with captive bubbles and it is conceded that the original paper described another avenue to an old flotation goal. The field of application is restricted and we would not work with all the material illustrated by Klassen and Mokrousov.1 The particles in Figure 74(a) are far too large and irregular; material in Figures (b) through (d) could be employed for semi-quantitative work in spite of obvious disadvantages; Figure 74(f) represents ideal conditions. We have studied this mineral-collector association in the size range given and results were satisfactory. For larger pick-up values than that illustrated an induction period of more than 0.01 second was required (actually 90 seconds for a maximum bubble load at pH 7.2 with 25 g/t oleic acid!). REFERENCE 1. KLASSEN,V. I. ANDMOKROUSOV,V. A., 'An Introduction to the Theory of Flotation,' Butterworths, London, 128, Figure 74, (1963). Mr Slander and Mr Kooij Researchworkers in a practical mineral development laboratory may well ask what contribution yet another micro-technique can make to the problems of large scale ore flotation. The obvious answer is that there can be little or no direct translation of results obtained with a static system comprising air bubble and pure mineral concentrate to a dynamic multicomponent operation. However, for the rapid study of one mineral or variable some small scale apparatus must be employed. In the Anglo American Research Laboratory, the described semi-quantitative pick-up technique has filled a niche and requirement. For ourselves, the system represents a definite advance over the contact angle approach in that samples of minerals conventionally prepared in laboratory or plant may be used, which is a desired step nearer flotation. We bracket this pick-up apparatus with the Hallimond tube1,2 and evidence is now to hand that pick-up curves may often be related to flotation recoveries obtained from this tube with pure mineral samples and from the Fuerstenau glass cell3 with the total ore at low pulp densities. We would not wish to push the comparison of pick-up results past this stage for there is much published development work relating the Hallimond and Fuerstenau equipment to flotation on a larger scale. At the Anglo American Research Laboratory for example, a test in a Fuerstenau cell is often the final integrated step in laboratory investigations into the TORCO process. As these contributors rightly point out, pick-up tests can offer nothing towards the determination of optimum reagent dosage for large scale flotation. This is the function of bench-type flotation cells with up to 2 kg batches of ore. At this level, collector performance and consumption and physical properties of the froth are more comparable with large scale operation. The pick-up cell, Hallimond tube and Fuerstenau cell are essentially equipment from which the effect of control parameters can be derived. For the assessment of collector behaviour, the pick-up approach is rapid and economic and we offer here a pick-up contribution towards the flotation of Witwatersrand uraninite with anionic sulphonate collectors (Fig. 1). A large crystal of the local mineral was not available for contact angle measurements and owing to its low concentration in Witwatersrand gold-bearing reef, a small sample was laboriously obtained by tabling, superpanning and heavy medium separation. The pick-up values of a sized portion were determined by the described procedure in the presence of nine petroleum sulphonate collectors. Responses fell into two categories; "normal" curves (dotted lines) and a group of collectors which were very active at low concentration but showed depression of pick-up at the higher levels. The similarity in form of curves for collectors 1 and 3 was apparent and reagent 3 was found to be simply a diluent of 1. Otherwise, collector performance could not be related to either sulphonate content or molecular weight of the active constituent. However, reagent 2 gave the best performance in a bench flotation cell with regard to overall uranium distribution but, as predicted, reagent 1 yielded the best grades. Later pick-up tests with a similar class of collector have suggested that depression at high reagent concentrations may be due to "bubble armouring" whereby an hydrophilic air-liquid interface is produced which rejects mineral attachment. Prolonged investigations with the same mineral sample have not been required except for the study of uraninite which lasted for more than a year. Variation in pick-up response could not be detected over this period during which the mineral was stored under distilled water. The only visible change was a small efflorescence of lead sulphate, readily removed and decanted off after stirring with a glass rod in the sample tube. In its main role as a "trouble-shooter", the pick-up method is applied to fresh mineral samples taken from a flotation plant and soon discarded or from a current run in the ore-dressing laboratory. After production of a concentrate, a solvent cycle, as described in the original paper, may be required to remove heavy organics or other contaminants as when a sample has been taken from circuits containing detergents, grease or return flotation solutions. This solvent cycle will not remove chemisorbed collectors and we prefer not to work with minerals from flotation tailings or with pick-up cell discards. It has been thought preferable to answer the contributors' other apprehensions with regard to sample preparation, activators, depressants and the physical properties of reagents in another paper on offer to this Journal. It covers pick-up investigations relating to the flotation of nickeliferous pyrrhotite at two Anglo American Corporation Mines, which approach seemed the correct orientation for a reply to another contributor to this paper.

Prof C T O'Connor holds the degrees of BSc, BSc Hons, University of Cape Town (UCT), where he started his academic Lecturer in the Department of Physical Chemistry in 1976. Mr P Smith, educated in England and the former Southern Rhodesia, joined Gold Fields of South Africa in 1966 as a Metallurgical Learner Official. After obtaining a BSc Eng at the University of the Witwatersrand in 1972, he returned to Gold Fields. Mr P D K Robinson was born in Zimbabwe, and was educated at Dale College in Kingwilliamstown, matriculating in 1952. He holds a Mine Surveyor's Certificate obtained in 1961) and a Mine Manager's Certificate (obtained in 1966), as well as an EDP from the University of the Witwatersrand.

Jan 1, 1991

By A. Rödfalk, P. Bloemer, J. P. Nilsson, N. Brogden

"Reliable and accurate metal transfer information during silicon tapping from an EAF is invaluable for decision-making and process optimization, while obtaining such information safely is a necessity.Elkem Thamshavn Norway, a producer of metallurgical-grade silicon, identified inherent safety problems with gauging fill levels in ladles using dip bars while molten metal was continuously pouring from a rotating EAF. Operator safety was a paramount concern, and an alternative automatic method of controlling the tapped fill level needed to be found.It was also considered that further benefits could be achieved such as monitoring the tapping flow from the EAF in order to identify any clogging, as well as the potential to use the live feed from such a system to assist decision-making regarding work around the taphole area.Agellis Group AB, Sweden, a company with over 30 years of experience in gauging molten metal levels in the metals industry, was able to design a solution for Elkem Thamshavn that would provide the required real-time process data while enhancing operator safety.This paper shows how the Agellis AB EMLI-L system was successfully installed at Elkem Thamshavn’s EAF continuous tapping area, how ladle fill levels were constantly monitored, and how full ladles were replaced by empty ones without the need for operators to be in the tapping area to take level readings. The results were used to compare the accuracy and reliability of Elkem Thamshavn’s current measuring methods with that of the EMLI-L system. The paper also covers how problems such as how to connect, run, and protect cables in and around the EAF tapping area, as well as connector and cabling survivability during the three day refractory pre-bake period, were solved. Finally, the paper discusses the potential production improvements, maintenance requirements, and data integration attainable through the installation of the system, as well as the major safety improvements that have been achieved."

Jan 1, 2014

The Centenary Distinguished Lecture was held on Thursday, 24th March, 1994 at the Convention Centre of the Sandton Sun, Johannesburg at 20:00. Herewith the proceedings that followed. P.R. Janisch: The South African Institute of Mining and Metalurgy began life one hundred years ago tonight, and eight years (almost to the day) after the 1886 discovery of gold, which has impacted so profoundly on the course of events in our country since then. The Early Years That discovery was a mater of fortune, but not in the sense of the conventional prospector's lucky strike. Canny explorers, such as the Strubens, had been around for some years and, if George Harrison had not stumbled over the Main Reef when he did, someone else would surely have done so within months. The element of luck was that the gold-bearing rocks of the Witwatersrand actually lay exposed to sight. We now know that they are something of the order of 2,5 billion years old. Rocks of that age are usually covered by younger formations. In fact, the bulk of the Witwatersrand Basin is covered by lava, dolomite, and Karoo measures. What, one wonders, would our history have been had the Karoo, which stops at the Vaal, extended no more than 60 kilometres further north. Dr H. Scot-Russell A piece of advice attributed to Paul Kruger, the who was President of the South African Republic one hundred years ago, was the following: 'Seek from the past that which is good, and build on it for the future'. It is advice that can be applied universally and, whether deliberately or not, it must have motivated my predecessors when this Institute celebrated its 40th, 50th, and 75th birthdays. Those milestones were each marked by retrospectives, as Peter Janisch has so ably presented tonight on our hundredth anniversary. The parallels do not end there. We find ourselves in times no less daunting than those our predecessors. Next month will see the birth of a new kind of South Africa; so did May 1902, May 1919, and May 1948.

Jan 1, 1994

By T. R. Marshall

SAMREC (The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves) Clause 7 notes that ‘Documentation detailing Exploration Results, Mineral Resources and Mineral Reserves from which a Public Report is prepared must be prepared by, or under the direction of, and signed by a Competent Person.’ Similar statements with respect to Competent Valuators (CVs) and Qualified Reserves Evaluators (QREs) are contained in the SAMVAL (South African Code for the Reporting of Mineral Asset Valuations) and SAMOG (South African Code for the Reporting of Oil & Gas Resources) codes respectively. What does it mean to be a Competent Person (CP) in the context of compiling/signing-off on SAMCODE (South African Mineral Code) compliant documents? What do the registration and experience requirements mean? Who is ultimately responsible for the report and what does such responsibility prescribe?

Sep 1, 2021

By D. Bessinger, H. Kotzé, J. Beukes

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

Jan 1, 2006

By R. Tabanrad

This article examines the stability analysis of intake tunnels of Karun III dam & power plant. The tunnels have been excavated with a 3-dimensional and fairly complicated geometry in Pabdeh weak formation rocks at Zagros region. Due to the particular excavation geometry and inapplicability of plane-strain status, the stability of these excavations has been analyzed using both the 3D elastic software Examine 3D and the 2D non-elastic software UDEC simultaneously. The geomechanical parameters have been estimated by back analyzing the measured displacements from instruments, which were installed in the tunnels, and the parameters have been used in non-elastic numerical model. The results of the analysis show that the strains occurred in surrounding rock mass are less than the allowable failure strain and that the tunnels are stable. In addition, considering the results of non-elastic 2D analysis, the areas with unstable potentiality were identified and after the instability occurred at the areas predicted by the model , it was stopped up to the allowable strain limit through installing additional support . Bei diesem Artikel handelt es sich um eine Analyse der Festigkeit der Eingangstunnel des Damms und Elektrizitätswerks “Karoon III”.Die Tunnel haben drei Dimensionen und eine sehr schwierige Form und sind in brüchigen Felsen in “Pabedeh ,in Zagrossgebirge”eingebohrt.Aufgrund besonderer Form der Bohrung wurde ihre Festigkeit durch elastische dreidimensionale Soft-ware analysiert,die gleichzeitig die drei-und zweidimensionale unelastische Soft-ware UDEC benutzt hat.Die geometrische Parameter sind mit Ausnützung der Analyse berechneter eingesetzter Versorgungen,die in Tunnel aufgebaut sind,bewertet.Und diese Parameter sind in Zahlen-Analyse benutzt.Die Ergebnisse dieser Analyse zeigen,dass die Drücke an Felsen weniger als problematischer Grad der Drücke sind und die Tunnel fest sind.Ausserdem wurde mit einem Einblick auf die Ergebnisse der unelastischen zweidimensionale Analyse die eventuellen unfesten Teile bestimmt.Nach entstandener Unfestigkeit an diesen Teilen wurde die problematischeDrücke für Aufbau mehrere Anlagen gestoppt. Cet article examine l'analyse de la stabilité de tunnels de la prise de Karoun barrage III et centrale électrique. Les tunnels ont été excavés avec une 3 dimensionnel et compliqué géométrie dans Pabedeh que la formation faible balance à région Zagros équitablement. Dû à la géométrie de l'excavation particulière et inapplicabilite de statut de tension plane, la stabilité de ces excavations a été analysée en utilisant les deux le 3D logiciel élastique Examen 3D et le 2D logiciel non - élastique UDEC simultanément. Les paramètres du geomechanical ont été estimés en analysant le déplacement mesuré d'instruments qui ont été installés dans les tunnels et les paramètres en arrière a été utilisé dans les modèles numériques non - élastique. Les résultats de l'analyse montrent que les tensions se sont produites dans masse du roc environnante est plus petit que la tension de l'échec admissible et que les tunnels sont stables. De plus, les régions avec potentialité instable ont été identifiées étant donné les résultats de 2D analyse non - élastique, et après que l'instabilité se soit produite aux régions prédites par le modèle, il a été arrêté jusqu'à la limite de la tension admissible à travers installer du support supplémentaire.

Jan 1, 2003

By C. A. Preece

Finsch Diamond Mine, part of De Beers Consolidated Mines (DBCM), is situated between Kimberley and Postmasburg in the Northern Cape, South Africa. The kimberlite pipe was discovered in 1960 and De Beers assumed full mining rights three years later. Production commenced in 1966 from an opencast mine, and the operation moved underground in 1990 by developing and implementing a new mining method of blast hole open stoping. A mechanized block cave was brought into production in 2005. While block caving was not new to DBCM, with productive caves having operated in Kimberley and Cullinan, from the outset, the Finsch caving operation was designed as the most advanced with a semi-automated ground handling system. The extraction level was laid out as a single sided herringbone system due to the very poor ground conditions on the south side of the pipe. These factors combined to create a unique environment, which necessitated a completely new approach to draw control. The required system was developed by a team consisting of DBCM personnel from head office and Finsch, GEMCOM and Sandvik-Tamrock, the equipment manufacturers. It was essential that the system could be run quickly, provide daily updates and issue calls directly to the LHDs. It was also important that the base data were obtained from the resource model, which was to be depleted on a monthly basis, thus forming a close link between mine planning and draw control. A further requirement of the system was that it would form a central database for the extraction operation where all data pertaining to delays and changes in conditions, be they production or ground condition related, could be recorded and analysed. The design brought together empirical rules and tables developed at Cullinan plus concepts from programming developed for the front cave at Koffiefontein so that the new system was based on sound practical experience. These facets were incorporated into PCBC (GEMCOM) and CMS and PCS (Sandvik-Tamrock programmes). The system has now been operational for just under a year and while modifications have had to be made, it has proved itself as a practical and reliable tool with which to manage the draw control at Finsch. The system is unforgiving and has forced the production team to focus on the specified drawpoints. Problems have been encountered but most of these have been related to re-educating a workforce, familiar with a flexible mining method, to the strict discipline required for a modern block cave.

Jan 1, 2007

A manual on mines rescue, safety and gas detection, by J. Strang and P. Mackenzie-Wood. Australia, Austcue, US$25. (Available through Hampo Systems (Pty) Ltd. Reviewer: W. Holding. The book had its origins in a set of notes used by one of the authors for training purposes at the Southern Mines Rescue Station in New South Wales

Jan 1, 1987

By D. Sethuram, P. G. Koppad, S. Iyengar, R. Shobha

TiB2 and CeO2 particle-reinforced Al6061 hybrid composites were manufactured using stir casting and hot rolling techniques. The base alloy and composites were hot-rolled at 500ºC and a 50% reduction was achieved through 12 passes. The effect of varying TiB2 and CeO2 particle additions on the microstructure and mechanical properties of the Al6061 matrix was studied. Scanning electron microscopy showed uniform dispersion of both the reinforcements, with good interfacial bonding. Microhardness and tensile properties like yield and tensile strength were found to be higher for hybrid composite with 2.5% TiB2 and 2.5% CeO2 compared to Al6061 alloy and other hybrid composites. The increased tensile strength is attributed to good dispersion and interfacial bonding between the particles and Al6061 matrix. Fracture analysis using a scanning electron microscope revealed ductile fracture for the Al6061 alloy and mixed characteristics of ductile-brittle fracture for hybrid composites

Oct 1, 2021

By J. T. Nel

The Kroll process is the traditional method of producing zirconium metal by reduction of zirconium tetrachloride with magnesium metal. This paper discusses the production of zirconium metal in a plasma reactor. Anhydrous low-hafnium ZrCl4 and Mg metal were fed continuously to a 30 kW non-transfer plasma reactor at a rate of 0.31 kg.h-1. Due to losses in the system the recovery of crude product was 77.5 %. After purification to remove unreacted feed material and MgCl2 by leaching, >98 % pure zirconium metal powder was obtained. The overall recovery of purified Zr was 74 %. The conversion efficiency of the process was 95 %.

Jan 1, 2012

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

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

Jan 1, 2003

By Timo Niitti, Sami Grönstrand

n today's marketplace with high metals prices, many operations are faced with the challenge of improving recovery and at the same time maximizing availability. New operations under feasibility studies have the same requirements, with the additional need for ever higher capacities. Economies of scale have proved a vital competitive advantage in the game of ore dressing. Flotation is the most widely used method for extracting valuable minerals from ore - despite its mature age of 100 years. Customer demand has driven the development to increasing cell sizes, and in most cases, this has brought the advantages of both lower capital expenditure and lower operational and maintenance cost. The challenge of scale up, however, is to meet the metallurgical performance requirements in the larger volumes. The paper outlines recent trends and developments in flotation technology, and presents new solutions designed to address the needs for increased capacities as well as improved performance. Whether the goal is to improve existing operations or to scale up new equipment, computer aided tools are playing a key role in shortening the development cycle and reducing costly trial-and-error tests in full scale. Using the new tools and validation thereof will be outlined, as well as the development principles behind the new solutions. Plant results and experiences with the new developments are presented and discussed in several cases around the world.

Jan 1, 2007