Search Documents

By M. M. Makhofane

Anhydrous zirconium tetrafluoride can be used as a precursor for the manufacturing of nuclear-grade zirconium metal. This can be done by fluorinating plasma-dissociated zircon with ammonium bifluoride in a batch reactor. This paper describes the batch process. It was proved that anhydrous zirconium tetrafluoride can be manufactured by this route as confirmed by X-ray diffraction. The process shows potential for scaling up to the kilogram scale and possibly the tonnage scale.

Jan 1, 2012

By P. J. Le Roux

"Mining companies are under constant pressure to reduce their cost structures to sustain profitability. In mines using an open stoping mining method, dilution often has a significant effect on profitability. At Target mine in South Africa, dilution in some open stopes was found to exceed 10%, falls of ground being a major contributor to the problem. This dilution can reduce the recovered grade from 5.5 to 4.5 g/t, resulting in a potential loss of about R21 million per month based on a gold price of R240 000 per kilogram. In addition to the cost of dilution, the cost of damage to, or loss of, trackless equipment as a direct result of falls of ground in open stopes is significant. Other associated costs include transport, hoisting, secondary blasting, milling, and plant treatment of waste material. Stable open stopes are essential in order to reduce falls of ground. Back-analyses of stope instability at Target mine have indicated that conventional rock mass failure criteria are unsuitable for stope design. An alternative strain-based criterion has been developed, and has proved to be very successful, allowing the stability of open stopes to be calculated reliably. Since its implementation in 2010, dilution and equipment damage have decreased markedly, creating value for the mine. IntroductionMines that make use of an open stoping mining method aim to extract only the ore, leaving the waste behind. Many orebodies have well-defined boundaries between the ore and the waste rock. In such orebodies, the introduction of waste into the ore due to overbreak dilutes the grade. In massive disseminated orebodies, dilution is less problematic. Overblasting, falls of ground, or other causes may result in dilution. A study undertaken in Canada (Pakalnis et al., 1995) found that approximately 51% of all underground metal mines utilized open stoping mining methods and, from surveys conducted at these mines, open stoping operations experienced dilutions of up to 20%, and occasionally more. Dilution of this magnitude has a significant economic impact on any mining venture. Research carried out in Australia by Capes (2009) came to the same conclusion."

Jan 1, 2017

By J. N. Van der Merwe

"Platinum is a highly valuable resource, its safe and economic extraction is paramount. The success of platinum mining by the bord and pillar method depends heavily on a comprehensive and dependable pillar design method. Pillars need to be large enough to safely support the load and small enough to avoid loss of resources. A critical evaluation of current pillar design systems used in narrow-reef platinum mining was undertaken using practical experience from a large feasibility-stage platinum exploration project, supplemented by observations from several platinum mines in Zimbabwe. An extensive literature survey was undertaken in order to determine the current status of design systems. Through this approach, the shortcomings of current pillar design systems are highlighted. Areas are proposed for further research to obtain a better understanding on how additional factors influence pillar system stability. The exploration work highlighted how rock mass classification methods can be utilized in determining the overall strength of pillars. Current pillar design systems for narrow-reef platinum mining consider width-to-heightratio (usually with different exponents for width and height) and the strength of the pillar material. However, there are many more important factors that are not considered and which have a bearing on pillar system stability. An in-depth study of these parameters with a view to establish effective narrow- reef platinum mining pillar design systems needs to be undertaken. IntroductionPillars have been used as a means of support since the early days of mining. Pillarsupported mining methods such as bord and pillar require a reliable design system for them to be successful. This paper presents an evaluation of the current hard-rock mining pillar design systems as applied to a practical large-scale narrow-reef platinum mining feasibility study. It is vital to have a dependable pillar design system for economic and sustainable mining. Using an extensive database collected from the project, the pillar strength formulae were tested and several discrepancies noted. This necessitates the establishment of more reliable pillar design systems. In narrow-reef platinum mining, large compressive stresses accompanied by geological and geotechnical factors contribute to pillar instability. A well-formulated pillar design system is required that accounts for such factors so as to minimize pillar failures."

Jan 1, 2017

By A. J. Dickson, A. M. Starfield

This paper reviews the progress made to date in the development of computer models of heat and moisture transfer from rock surfaces to the ventilating air in deep-level mines. The application of these programs to ventilation planning and design is discussed.

Jan 1, 2014

Mining plants operating in dunes north of Richards Bay have uncovered Iron Age archaeological material that spans the greater part of the past 2000 years. This was announced by archaeologists Gavin Whitelaw of the Natal Museum's Institute of Cultural Resource Management (ICRM), and Len van Schalkwyk and Mlungisi Ngubane of the KwaZulu Monuments Council (KMC), who are currently contracted by Richards Bay Minerals (RBM) to assess the cultural resources exposed during mining activities.

Jan 1, 1995

Carbon-concentration Meter The latest of these, the ultrasound-based carbon concentration meter, was developed by Mintek with original sponsorship by the Chamber of Mines Research Organization, and is now being manufactured and marketed worldwide by Debex Electronics in Johannesburg. Testing of detonators* The Chief Mining Engineer has asked the South African Bureau of Standards to monitor locally manufactured, as well as imported, detonators. This could ensure greater safety in fiery mines.

Jan 1, 1990

Book reviews Jones, M. J. (editor). Process engineering of pyrometallurgy. Proceedings of a joint meeting of the Institution of Mining and Metallurgy and the Institution of Chemical Engineers. London, Institution of Mining and Metallurgy, 1974. 105 pp. £6,50. Nim reports Report No. 1656 The analysis of geological samples for trace elements by direct-reading emission spectrometry. Report No. 1669 An assessment of the carbon-rod atomizer for the determination of silver.

Jan 12, 1974

It is perhaps somewhat unusual for a contributor to comment on the authors' reply to his critique. However, I should like to return to a specific comment made by the authors. Award to Bob Laburn The Federation of Societies of Professional Engineers (FSPE) is pleased to announce that the 1984 FSPE Award for Services to the Engineering Profession was presented to Dr R. J. (Bob) Laburn at a function held on 14th February, 1984.

Jan 1, 1984

Petrus (Peter) Lambooy was born in Johannesburg of Dutch-speaking parents on 13th November, 1911, and died in August 1988. These are the bare statistics, which obviously tell nothing of the years between and the man who lived them to the full.

Jan 1, 1988

By B. Strohmeier

An account is given of the use of a computer to control the performance of three ultra-high-powered electric-arc furnaces in Iscor 5 steelmaking plant at Vanderbijlpark, South Africa. Several of the reports and graphs printed by the computer are reproduced.

Jan 1, 1985

By L. P. Fatti

An important feature affecting the classification of a remotely sensed scene is that the data are, in general, spatially correlated. Various approaches are discussed towards incorporating the correlation between neighbouring pixels when they are classified on the basis of their spectral reflectance data.

Jan 1, 1987

1. Book reviews Perspectives in metallurgical development. London, The Metals Society. 338 pp. £29. Reviewer: John V. Bee Mechanics of oil shale, edited by K.P. Chong and J.W. Smith. London, Elsevier Applied Science Publishers Ltd, 1984. 603 pp. £75. Reviewer: R.W.O. Kersten 2. Recent publications CANADIAN MINERAL POLICY SECTOR. Metallurgical works in Canada. Primary iron and steel 1984. Mineral Bulletin MR 203. Ottawa, Canadian Government Publishing Centre, Supply and Services, 1985. $6.00. Tin and its uses no. 143. Greenford (England), International Tin Research Institute, 1985. Mining 1985, edited by Diana Russell. Harlow England), Longman Group Ltd, 1985. 540 pp. £46. The following books are available from CRC Press, Inc., 2000 Corporate Boulevard N.W., Boca Raton, Florida 33431, U.S.A. Inorganic ion exchange materials, edited by A. Clearfield. 304 pp. $100. Polyurethane foam sorbents in separation science, by T. Braun. $80. Advanced particulate morphology: theory and practice, by J.K. Beddow and T.P. Melloy. 208 pp. $79. CRC handbook of atomic absorption analysis, edited by A. Varma. 2 vols: vol. I $114, vol 11 $102. CRC handbooks of inorganic elecrochemistry, edited byL. Meites, P. Zuman, E.B. Rupp, andA. Narayanan. 3. Mintek reports Report M169 The preparation of three South African coals for as reference materials. Report M190 The preparation and certification of a South African phosphate concentrate for use as a reference material. Report M191 The agglomeration of fine material for bacterial heap leaching. Report M197 A computer programme to monitor the performance of an X-ray-fluorescence spectrometer. Metallurgical award The 1984 Acta Metallurgica Gold Medal has been awarded to Professor John W. Christian of Oxford University. The medal is an international award that was established in 1974 to recognize outstanding ability and leadership in materials research. Proterozoic volcanic suites An international symposium will be held at the British Geological Survey, Keyworth, Nottingham, U.K., from 2nd to 5th April, 1986. Entitled 'Geochemistry and Mineralisation of Proterozoic Volcanic Suites', this special meeting of the Geological Society will discuss the geochemical evidence for the nature of volcanism during the Proterozoic. Powder metallurgy Every second year the International Powder Metallurgy Conference, the world's leading event in powder metallurgy, is organized and held alternately in North America and Eruope.

Jan 1, 1985

By W. Wittke, J. Gattermann

ABSTRACT: One alternative to close a radioactive waste repository in rock salt is the construction of a “Cross Section Closure (CSC)“ sealing barrier. The proposed material for the CSC is highly compacted bentonite. To investigate the swelling behaviour of a highly compacted bentonite a large number of laboratory tests were performed. In addition, large scale model test were carried out to demonstrate the development of a nearly homogeneous and isotropic swelling pressure. The results of the large scale model tests were interpreted numerically based on the models for stress-strain behaviour and water uptake which are implemented in the finite element codes FEST03 and HYDOPO. The investigations show a good agreement of the results of the model tests and the corresponding analyses and show, that the theoretical models are capable of describing the behaviour of sealing structures based on highly compacted bentonite. ZUSAMMENFASSUNG: Eine Möglichkeit für den Verschluß eines Endlagers für radioaktive Abfälle im Steinsalz ist die Konstruktion einer Querschnittsabdichtung aus hochverdichtetem Bentonit. Zur Untersuchung des Quellverhaltens von hochverdichtetem Bentonit wurden eine große Anzahl von Laborversuchen durchgeführt. Um die Entwicklung eines nahezu homogenen und isotropen Quelldrucks nachzuweisen, wurden darüber hinaus auch Modellversuche in größerem Maßstab durchgeführt. Die Ergebnisse dieser Modellversuche wurden im Hinblick auf die Wasseraufnahme und das Spannungs-Verformungsverhalten mit Hilfe numerischer Berechnungen mit den finite Element Programmen FEST 03 und HYDOPO interpretiert. Die Untersuchungen zeigen gute Übereinstimmungen zwischen Versuchs- und Berechnungsergebnissen. Die numerischen Modelle sind somit geeignet, das Verhalten von Abdichtungsbauwerken aus hochverdichtetem Bentonit zutreffend zu beschreiben. RÉSUMÉ: Une possibilité pour fermer un dépôt final de déchets radioactifs dans sel gemme est la construction d'un étanchement de coupe transversale, fabriqué de bentonite fortement compacté. Pour étudier le comportement de gonflement de bentonite fortement compacté, de nombreux essais en laboratoire ont été exécutés. En outre, des essais sur modèle sur une plus grande échelle ont aussi été exécutes afin de prouver le développement d'une pression de gonflement à peu près homogène et isotrope. Les résultats de ces essais sur modèle étaient interprétés en vue de l'absorption d'eau et du comportement contraintes-déformations par le moyen de calculs numériques avec les programmes d'éléments finis FEST03 et HYDOPO. Les études montrent de bonnes conformités entre des résultats d'essai et de calcul. Les modèles numériques sont ainsi capables de décrire justement le comportement d'ouvrages d'étanchement fabriqués de bentonite fortement compacté.

Jan 1, 2003

By M. M. Makhofane

Anhydrous zirconium tetrafluoride can be used as a precursor for the manufacturing of nuclear-grade zirconium metal. This can be done by fluorinating plasma-dissociated zircon with ammonium bifluoride in a batch reactor. This paper describes the batch process. It was proved that anhydrous zirconium tetrafluoride can be manufactured by this route as confirmed by X-ray diffraction. The process shows potential for scaling up to the kilogram scale and possibly the tonnage scale.

Jan 1, 2012

By C. L. de Jongh

Fracturing of the rock caused considerable difficulties during the boring of a deep-level tunnel in hard rock. A pilot bore was suggested as a possible means of reducing the effect of the fracturing, and this possibility was investigated theoretically by means of a three-dimensional elastic stress analysis. Failure criteria were applied to the results of this analysis, and it was found that fractures predicted by the use of a simple criterion of limiting tensile macrostrain criterion agreed remarkably well with in situ observation. It was concluded that fracture could not be avoided and that a pilot bore was likely to aggravate tunnelling conditions.

Jan 1, 1978

By S. W. Evans, G. Pienaar

Weldable steel plate with a good combination of strength and toughness is currently produced from 0,12 to 0,28 per cent carbon low-alloy steel heat-treated by roller quenching and tempering. Alternatively, steel plate of the same strength can be produced at a lower production cost by the use of very-low-carbon steel (0,03 to 0,08 per cent carbon) processed by in-line quenching without tempering. This paper reports the results of experimental work on these steels, and compares them with the properties of conventional steel. On thinner sections, it was found that the properties of the experimental steels compare favourably with those of conventional grades.

Jan 1, 1989

By A. Miller, M. Bétournay

The main objectives of the Mine Mechanisation and Automation program (MMAP) are to enhance health and safety in underground mining operations, facilitate mechanization and automation in narrow- vein and deep mines, provide sound science to regulatory agencies and improve mine profitability. The program, which has a unique underground and surface industrial scale facility, is involved in many multi-partner projects, like hydrogen fuel cell applications, electrification and hydraulification of underground mines, reduction of noise and vibration, miner location device, explosive-free blasting and hoisting. The paper presents an overview of the Mine Mechanisation and Automation Program of Natural Resources Canada and some of the main projects.

Sep 1, 2001

Mixed integer programming (MIP) has been used for optimizing production schedules of mines since the 1960s and is recognized a shaving significant potential for optimizing production scheduling problems for both surface and underground mining. The major problem in long-term production scheduling for underground orebodies generally relate to the large number of variables needed to formulate a MIP model, which makes it too complex to solve. As the number of variables in the model increase, solution times are known to increase at an exponential rate. In many instances the more extensive use of MIP models has been limited due to excessive solution times.

Jan 1, 2010

By Y. F. Bulgakov, Y. V. Melnikova, V. S. Zakharov

A new technology of atmosphere in inertization of fire section with the help of gazeous nitrogen is presented in the report. This technology is based on membrane air subdivision into two streams, concentrated with nitrogen (up to 99%) and with oxygen correspondently with subsequent giving them into the place of fire. This technology belongs to environmentally friendly ones and it has a great number of technical, mobile and economic advantages comparing with the rest of well-known methods of fire extinguishing. This technology application in Ukrainian coal mines allowed to reduce the member of isolated places of fire at the expense of their extinguishing efficiency.

Jan 1, 2003

1. New books Extractionmetallurgy'81. London, Institution of Mining and Metallurgy, 1981. 441 pp. $40. Structures and properties of engineering alloys, by W. F. Smith. London, McGraw-Hill, 1981. 512 pp. R89,65. Rock and mineral analysis, by W. M. Johnson and J. A. Maxwell (editors). 2nd ed. New York, Wiley, 1981. 424 pp. $40. Mining methods and equipment, by Mining Information Services. London, McGraw-Hill, 1981. 218 pp. International directory of acronyms in library, information and computer sciences, by P. M. Vaillancourt. New York, Bowker Publishing Co., 1980.516 pp. 2. New journals Trends in analytical chemistry (TRAC), Amsterdam, Elsevier, 12 issues per year. Subs. for Volume I (16 issues) D.H 95.50. Engineering management international, Amsterdam, Elsevier, 4 issues per year. V.S. $32.50, D.H. 70.00. 3. Mineral policy sector publications Mineral Bulletin MR 188. Vanadium: an imported mineral commodity. $3.60. Mineral Bulletin MR 190. Canadian mines: 1980 perspective. $3.00. Canadian mineral survey 1980, by the staff of Mineral Policy and Energy Sectors. $1.00. 4. NIM reports Report 2090 Observations made during the dig-out of a 48 MV A ferrochromium furnace. Report 2110 The investigation of a fracture on one side of a skip bridle in a mine shaft. Report 2111 Pilot-plant tests for the recovery of chromite and the noble metals from the UG-2 Reef at Maandagshoek. Report 2112 The behaviour of UG-2 chromite concentrates during smeUing. Report 2113 M uUivariable control of a milling circuit at East Driefontein Gold Mine. Report 2115 Estimation of material variation in powdered materials Report 2116 Optimum operation of a direct-reading spectrometer with excitation by a 5 kW inductively coupled plasma torch. Report 2121 Five robust indicators of central value. Report 2124 The direct determination, by differential pulse anodicstripping voUammetry at the thin mercury-film electrode,of cadmium, lead, and copper. Report 2127 The preparation of a reference material of South African zirconium concentrate from Richards Bay. Report 2128 The determination, by differential pulse anodic-stripping voltammetry at the thin mercury-film electrode, of cadmium and thallium in six NIMROC reference materials Report 2130 The organizing of conferences. Research grant The Board of Directors of International Precious Metals Institute in conjunction with Gemini Industries, Inc., a California-based refiner of precious metals, recently announced a Gemini Research Grant of $3000 will be awarded annually to a graduate student who is pursuing studies in metallurgy, chemical processes as it pertains to precious metals, or materials sciences, and who is performing or planning research studies in the precious metals. Accidents and diseases The Third International Colloquium for the Prevention of Occupational Accidents and Diseases in the Iron and Metal Industry is to be held on 15th and 16th June, 1982, in Palma de Mallorca, Spain.

Jan 1, 1981