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By J H. Sullivan

Contents Background information Locality of Kumba?s Iron Ore Mines Sishen?s Product Specifications Geological Description of boreholes Sample Preperation Block delineations Production Geology Process Laboratory information Turnover times reached Inter Laboratory Comparisons Quality control activities in lab Purpose of laboratory Results attained Standard samples Monitoring of processes with QA/QC standards Mean paired difference of duplicates Duplicate samples Conclusion

Jan 1, 2005

By G. Popplewel

Commencing with the Pre-Feasibility Study (PFS) conclusions, the Orapa 3 process design evolved through a phase of value-engineering studies. An overall re-evaluation of the originally proposed process design was necessary both in order to address the interim increase in target throughput from 9.8 Mtpa to 12 Mtpa as well as to increase capital efficiency. In the interests of clarity, the PFS process design for Orapa 3 has been omitted from this paper, as it is no longer relevant. Recognition is however due to those engaged in earlier phases of the Orapa 3 project with respect to fundamental mass-balancing modelling; and ore and diamond characterization, which fanned the basis for the process design that has evolved from feasibility study activities.

Jan 1, 2010

By D. N. Golenkov, N. I. Lomaka, A. V. Kozub, T. V. Ignatova, E. V. Shelepov, D. O. Sharkovskiy, A. V. Chanturiya, R. I. Ismagilov

The modern Russian iron ore mining industry is faced with multiple challenges from everincreasing requirements of steel-making, the value of iron ore concentrates, depletion of high-grade ore reserves and complications of the mining and geologic environment’s necessity to process low-grade ores with complex material composition and low valuable mineral content; with finely disseminated aggregates of metal and non-metal minerals responding similarly to processing. The upgrade of the existing operations’ fine wet screening was implemented by Metalloinvest; as well as the design of a process flowsheet for concentration oxide ferruginous quartzites with low concentrating ability. The scientific basis for improvement of low grade ore concentrating efficiency and the upgrade of market product quality is supported by an in-depth study of ore characteristics, application of high performance equipment for separation of fine-grained mineral aggregates and use of depressor selective to ferruginous minerals in the flotation process. The benefits of wet fine screening have been proven by industrial scale tests; as well as the feasibility of significant upgrades in product quality which have been confirmed as a result of the tests. A road-map for the upgrade of an existing process for the concentration of unoxidised ferruginous quartzites deposited in the Mikhailovskoye ore field was developed, based on the industrial scale test of a fine screening process. With reference to the ability for concentration, three major ore types oxidised ferruginous quartzites were defined as a result of comprehensive geological mapping and process sampling: oxidised ferruginous quartzites with good concentrating ability: over Fe67% grade of concentrate with ca. 80% iron recovery; oxidised ferruginous quartzites with moderate concentrating ability: Fe65-67% grade of concentrate with 70-72% iron recovery oxidised ferruginous quartzites with low concentrating ability: below Fe60% grade of concentrate (cannot be processed into desired grade market product). A process flow diagram combining magnetic separation and flotation has been designed and recommended for implementation based on the in-depth research of defined Mikhailovskoye deposit iron oxide types, including grain size, chemistry, petrographic, mineralogy, hematite and magnetite grain size distribution and liberation analysis.

Jan 1, 2020

By P. A. Von Wielligh

Without minerals, man cannot possibly hope to maintain his present standard of living. Professional mining men throughout the world, particularly in mineral-exporting countries like South Africa, are faced with the increasingly difficult task of ensuring adequate supplies of minerals. The problems of gradually diminishing mineral reserves and rapidly rising mining costs can to a certain extent be overcome by the use of more-sophisticated technological techniques and by the improvement of efficiency wherever possible. However, there is growing concern in some quarters, that, despite the ingenuity of engineers, geologists, metallurgists, and scientists, the earth's mineral reserves will eventually become insufficient to meet man's needs. In order to ensure the continued well-being of the earth's population, it is therefore imperative that more attention should be paid to mineral research and the training of specialists in the field of mineral reclamation.

Jan 1, 1978

By T. J. Otto, C. Musingwini

"The objective of any mining company is to sustainably maximize the net present value (NPV) throughout the life-of-mine (LOM). The expected NPV over the LOM is calculated based on a mine plan, yet the actual value realized by the mining company depends greatly on the level of intertemporal execution against the mine plan. Consequently, a major key performance indicator (KPI) that is often overlooked in open pit mining, due to a greater focus on temporal KPIs, is the degree of spatial compliance to the mine plan. Such focus sometimes leads to short-term actions being detrimental to long-term plans. In this paper we describe the development and implementation of a spatial mine-to-plan compliance reconciliation approach for an open pit mine. Application to a case study open pit iron ore mine in South Africa indicated a significant improvement in the spatial mine-to-plan compliance, from 69% to 94% over a three-year period from 2014 to 2016. These results indicate that implementation of the proposed spatial mine-to-plan compliance reconciliation approach can contribute positively to improving the level of spatial execution and assists in improving the alignment between short-term, medium-term, and LOM plans.IntroductionThe objective of any mining company is to maximize the net present value (NPV) throughout the life of mine (LOM). However, this objective needs to be fulfilled in a sustainable manner that considers the needs of various stakeholders, including employees, shareholders, and local communities where the mines operate. The expected NPV is calculated using a mine plan as a basis. Mine planning broadly involves identifying a strategy to exploit the mineral resource in a way that maximizes value at an acceptable level of risk throughout the LOM (Tholana and Neingo, 2016).The mine planning process is a well-recognized component in the mining value chain of an open pit mine. Figure 1 reflects the relative position of mine planning within a typical open-pit mining value chain from the mineral resource to the market"

Mar 1, 2019

By K. L. Morton

This technical note reviews the status quo of mud rushes and flooding, which have claimed them lives of many people in underground mines in South Africa and globally. Given that the causes are well known and can be managed, the note calls for the development of a national and global standard on flood and mud rush prevention in order to save lives.

Mar 30, 2026

By M. M. Oosterveld

"In South West Africa diamonds are mined from ancient beach deposits by the Consolidated Diamond Mines of South West Africa, Limited.To improve the control of mining production, a computer is used for the calculation of statistically more accurate and homogeneous ore blocks. Geological and sampling information has been digitized and stored on magnetic files.The figures derived for each block entail the calculation of the diamond size frequency distribution, the diamond density distribution and the ore reserve by using the density distribution.The diamond size frequency distribution is used for estimating the revenue in an ore block.A description is given of how a linear programming system can be used for production planning."

Jan 1, 2014

United Kingdom mineral statistics 1977. Home, D., Squirrell, H. C., and Venkatesan, J. (compilers). London, Her Majesty's Stationery Office, 1978. 156 pp. £10,25. Copper mining and management. Navin, Thomas R. University of Arizona Press, Box 3398, Tucson, Arizona 85722. ISBN 0-8165-0586-1. 426 pp. Illustrated. Price Metal statistics 1967-1977. 65th edition. 1978. Metallgesellschaft AG, Reuterweg 14, D 6000 Frankfurt am Main, Fed. Rep. of Germany. 382 pp. Illustrated. Coal mine ground control. Peng, Syd S. John Wiley & Sons. ISBN 0-471-04121-1. 450 pp. Illustrated. £19.75 clothbound. Associate Professor and Chairman of the Uranium supply and demand: Proceedings International Symposium, London, July 1978. Spriggs, Michael J. and Casteel, Kyran D. (editors). Mining Journal Gemorfologiesewoordelys/Geomorpho logical vocabulary. Van der Merwe, J. S., en De Villiers, A. B. (samestellers).

Jan 1, 1979

By V. Sheikhzadeh, M. Saghaeian, N. Esmaeili, R. Hejazi, A. D. Ahmadabadi

The main challenges in most low grade iron ore deposits are finding the optimum flowsheet for beneficiation to achieve a final concentrate from both technical and economic viewpoints. Dry preconcentration techniques are being used to assist in reducing the amount of ROM feed to the plant. In this paper the benefits of utilising a dry cobbing magnetic separation technique for upgrading the product of HPGR in a closed circuit with dry screen 4 and 1.4 mm by performing a pilot scale test work was investigated. The experimental test work was done on two sample types of Yogi BIF magnetite iron ore located in Western Australia. Prior to magnetic separation studies, detailed characterisation of the feed materials including physical, chemical, mineralogical and magnetic properties were carried out. Furthermore, the effects of process parameters: drum rotation speed (1.5, 2.5 and 3.5 m/s), magnetic field intensity (1100 and 3800 gauss) and feed size (minus 4 and 1.4 mm) were investigated. The results revealed that sample type1 with 33.90% Fe could be upgraded to 41.51% Fe by using a stage of 1100 gauss dry magnetic separator with 69.12% weight recovery and 84.36% Fe recovery at a size of 4 mm. Also for sample type2, it is possible to increase Fe grade from 29.84% to above 36.68% with 75.58% weight recovery and 90.32% Fe recovery by applying one stage of 1100 gauss dry magnetic separator to a 4 mm size sample. Keywords: Banded iron formation (BIF), pre-concentration, dry cobbing technique, magnetic separator

Jan 1, 2020

By DeVerle P. Harris, David E. Euresty

"Potential metal supply refers to metals to be produced from as yet unknown deposits. Naturally, to measure potential supply requires, among other things, inference to the number of deposits, their tonnage, and their grade Thus, probability distributions were constructed for each 400-square mile cell in Northern Sonora, Mexico. A computer system was developed that simulated the occurrence of deposits for each cell, exploration for the deposits, and their exploitation. Evaluation was performed for each deposit by discounted cash flow analysis.An objective of this study was to explore the effect of the transportation network and required road or railroad construction upon potential supply. Consequently, the evaluation system was designed to consider the spatial location of a simulated deposit to the existing transportation network and the market destination. The construction of linkages to connect the deposit to existing transportation arteries as well as the carrying of the concentrates to the intended market were simulated. in terms of cost. The selection of the path took into account the existing terrain. This was done by digitizing topographical maps and representing the topography of the area by an orthogonal grid of elevations. The optimum route was selected by dynamic programming, meeting a prescribed gradient constraint. The potential supply of each cell was determined, allowing for the infrastructure effect."

Jan 1, 2014

By M. Pötsch, W. Schubert, A. Goricki

Geological and geotechnical data are essential for the design of tunnels. To determine the rock mass behavior and the support of a planned tunnel excavation a consistent method for rock mass characterization and excavation and support determination has been developed. Probabilistic data processing with analytical methods is used for the quantification of the procedure and allows an evaluation of the applicability and the technical risk of different excavation and support methods. The sensitivity of the procedure on selected input parameters is highlighted in a parametric study. Finally an application of the procedure illustrates the use of the described method of probabilistic excavation and support determination for tunnels. Des données géologiques et géotechniques sont décisives pour la planification d’un tunnel. Pour la détermination du comportement des strates, le choix du soutènement et de la méthode de progression une description compréhensible de la montagne a été développée. À l'aide d'un traitement de données probabiliste, la procédure proposée est transposée quantitative sur une base de méthodes analytiques. De cette manière l'évaluation des méthodes de construction et la détermination du risque technique deviennent possibles. La sensitivité de la procédure de différents paramètres d'entrée est représentée dans une étude de paramètre. Pour finir, l'application de la procédure décrite est montrée à l’aide d'un cas pratique. Geologische und geotechnische Daten sind entscheidend für die Planung von Tunnels. Für die Ermittlung des Gebirgsverhaltens und der Festlegung von Ausbruch und Stützung wurde ein nachvollziehbarer Ablauf der Gebirgsbeschreibung entwickelt. Mit Hilfe von probabilistischer Datenverarbeitung auf Grundlage analytischer Methoden wird die vorgeschlagene Prozedur quantiativ umgesetzt. Dadurch werden die Bewertung von Baumethoden und die Ermittlung des technischen Risikos ermöglicht. Die Sensitivität des Verfahrens von einzelnen Eingangsparametern wird in einer Parameterstudie dargestellt. Abschließend wird anhand eines Beispiels die Anwendung des beschriebenen Verfahrens gezeigt.

Jan 1, 2003

The April General Meeting of the Institute was held in Kelvin House, Johannesburg, on 15th April, 1970, at 4.30 p.m. Mr J. K. E. Douglas (President) was in the chair. There were also present eight Fellows: Dr J. M. Bereza, H. Britten, R. C. J. Goode, C. E. Mavrocordatos, P. W. J. van Rensburg (Council Members), C. A. Border, D. E. French and S. D. Hill. Four Members, J. A. Boyd, P. Crawshaw, D. P. Hugo and A. H. Munro. Two Associates, including I. Robinson. Eleven Visitors, including A. B. Gould, P. M. Haupt, B. Needleman and A. F. Wentzel. Secretary, D. C. Visser. Total Present, 27. OBITUARIES The President: "It is my sad duty to announce the death of the following: Leslie Richard Ulyate, Fellow, who joined the Institute in 1939 and passed away on 10th March, 1970. Stanley Sterling, Fellow, and Corresponding Member for Canada, who joined the Institute in 1926 and passed away on 25th March, 1970. As a mark of respect to the memory of the deceased and in sympathy with the bereaved I would ask you all to rise and observe a few moments' silence." MINUTES The President: "May we confirm the minutes of the General Meeting, held on 21st January, 1970, as published in the March, 1970, issue of the Journal?" Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates, having been published in accordance with By-Law 5.2.2., Council has elected them to membership of the Institute in the following grades: Associate: Rupert George CaIcott. Students: Clive Martin Davis, William Machiel Eksteen, Cecil John Tainton. From Student to Member: Dirk Johannes Hugo. "I welcome the newly-elected members to the Institute and congratulate the member who has been transferred to a higher grade." TALK AND FILMS The President: "Mr Ballantyne may I call on you to present your talk and films on the 'Continuous casting of steel'?" After the presentation of Mr Ballantyne's programme the President said, "Thank you very much indeed for your talk and films, Mr Ballantyne. This is a fast developing subject and we appreciate having such up-to-date information being made available to us, particularly those of us who are unable to go overseas for this purpose. We trust that you won't let the matter rest here, but will put everything down in a paper which we can publish at a later stage for the benefit of our members. Thank you once again." CONCLUSION The President: "I wish to thank members and visitors for their attendance, and now declare the meeting closed." The meeting closed at 6.10 p.m.

By A. G. Journel, CH. Huijbregts

"Centre de Morphologie MathématiqueSpecial problems arise in the evaluation of lateritic-type orebodies (Ni-Co, bauxite) or, more generally, orebodies affected by surface weathering. In this type of orebody, the vertical grade distribution shows, from the hangingwall downwards, a systematic increase followed sometimes by a certain decrease, or vice-versa. These trends appear together with irregular variations from one drill bole to the other.The problem is to characterize a vertical structure that is representative not only of the drill hole but of an entire panel or zone of influence, in order to define mineable thicknesses for given cut-off grades. The vertical grade distribution observed on the drillhole is replaced by a new curve, called 'derive' (drift), which is computed by 'universal kriging'.Once the vertical study is completed, new 'service-variables' are defined in the horizontal plane, such as mineable thickness and the corresponding average grade, economical functions (combination of the grades of several minerals). The local and global estimation of these variables can then be performed by a simple bi-dimensional kriging plan. The global estimation is summed up by several tonnage-cut-off grade curves.The practical valuation according to the above scheme of a New Caledonian lateritic nickel orebody is presented."

Jan 1, 2014

ENERGY 73 The First International Energy Exhibition will be held in Brussels from 13th to 18th May, 1973. Vllth INTERNATIONAL CONGRESS ON CYBERNETICS This congress will be held in Namur, Belgium, from 10th to 15th September, 1973. GRADUATE SCHOOL OF BUSINESS ADMINISTRATION University of the Witwatersrand The Sixth Executive Development Programme is scheduled to take place from 2nd July to 24th August, 1973. IFAC SYMPOSIUM 1973 Second announcement ofthe International Symposium on AUTOMATIC CONTROL IN MINING MINERALS AND METAL PROCESSING to be held at the University of New South Wales, Sydney, Australia, from 13th to 17th August, 1973. MINERALS AND ENVIRONMENT The effect ofthe mineral industry on the environment and mineral resources The Institution of Mining and Metallurgy, with the co-operation of the Institute of Quarrying and the Institution of Mining Engineers, will hold a Symposium "Minerals and the environment" at the Institution of Electrical Engineers, Savoy Place, from 4th to 7th June, 1974. COLLOQUIUM ON SLlMES DAMS The South African Institute of Mining and Metallurgy have great pleasure in advising members that a two-day colloquium on slimes dams is bei ng arranged for the 14th and 15th November, 1973. INTERNATIONAL SOLVENT EXTRACTION CONFERENCE This conference will be held at Lyon from 8th to 14th September, 1974. Particulars may be obtained from the Secretary: Dr A. Naylor, British Nuclear Fuels Ltd., Windscale and Carder Works, Seascale, Cumberland CA20 IPG, United Kingdom. Competition for Student Members of the South African Institute of Mining and Metallurgy Each year the Institute offers a prize (or prizes should the entries warrant it) of up to RIOO for the best paper or dissertation on a topic appropriate to the interests of the Institute. Proceedings of the Tenth International Symposium on Application of Computer Methods in the Mineral Industry (APCOM) The Proceedings of the APCOM Symposium held in Johannesburg from April 9th to 14th, 1972, have now been published. Members of the Institute may buy the Proceedings at a special price of R12,50 as against the list price of R25,00 to non-members. Verrigtinge van die Tenth International Symposium on Application of Computer Methods in the Mineral Industry (APCOM) Die Verrigtinge van die APCOM Simposium, wat op April 9 tot 14, 1972, in Johannesburg gehou is, is gepubliseer. Lede van die Instituut kan die Verrigtinge teen 'n spesiale prys van R12,50 koop, in teenstelling met die prys van R25,00 vir nie-Iede.

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

By K, J. MAUNDERS

This paper briefly describes a computerised model of the South African electricity system which has been developed jointly by the Atomic Energy Board and the Electricity Supply Commission. The results of an analysis of this system have been subjected to a fairly extensive sensitivity analysis which reveals that up to the year 1990 between 680 and 700 million tons of coal will be required for electric power generation, together with between 7 000 and 10 000 tons of uranium. This result is fairly insensitive to data variations, but the prediction of a cumulative requirement up to the year 2000, of between 1 300 and 1 800 million tons of coal and 25 000 to 70 000 tons of uranium, proves to be very data-sensitive.

Jan 1, 2014

By Z. Szczepanik, D. Milne, K. Kostakis

Abstract This paper presents the results of a series of creep tests performed on a total of nine samples of Lac du Bonnet granite from the Underground Research Laboratory near Pinawa, Canada. Each of the nine samples were subjected to stresses in excess of 80% of the average uniaxial compressive strength of the granite and were maintained at that level of constant loading for periods of time ranging between a few minutes and several months. Acoustic emission was recorded in order to monitor the development and accumulation of brittle microfracture damage in the samples throughout the long-term loading. According to previously published theoretical predictions and field results, as well as similar experimental results of creep tests in granite, samples should fail when loaded to 70% of their UCS for an extended period of time. Six of the samples did not fail when subjected to stresses in excess of 80% of their UCS over periods of several months and were subsequently subjected to uniaxial compression to failure. The average strength of the samples that had previously been subjected to long-term loading were comparable to the average published strength of this rock. Three of the nine samples had increased end confinement and these three samples failed under long term loading. Résumé Cet article présente les résultats d'une série d'essais de fluage de roche exécutés sur neuf échantillons de granite de Lac du Bonnet, du laboratoire souterrain de recherches près de Pinawa, Canada. Chacun des neuf échantillons a été alors soumis aux charges au-dessus de 80% de la résistance à la UCS moyenne du granit et a été maintenu à ce niveau du chargement constant pendant des périodes s'étendant entre quelques minutes et plusieurs mois. L'émission acoustique a été enregistrée pendant les essais afin d'obtenir des indications des dommages pendant le chargement à long terme. Selon des résultats théoriques précédemment édités et les résultats expérimentaux semblables des essais à long terme en granite, échantillons devrait échouer si chargé à 70% de leur UCS pendant une période prolongée. Six des échantillons n'ont pas cassé quant ils ont été soumis aux charges au-dessus de 80% de leur UCS et ont été plus tard soumis à la compression uniaxiale à la rupture. La force moyenne des échantillons qui avaient été précédemment soumis au chargement à long terme étaient comparable à la force éditée moyenne de cette roche. Trois des neuf échantillons avaient augmenté le confinement de fin et ces trois échantillons ont cassé sous le chargement à long terme. Zusammenfassung Dieser Artikel beschreibt die Resultate von Kriechversuchen, die an neun Proben aus dem Lac du Bonnet Granit des "Underground Research Laboratory" bei Pinawa in Kanada durchgeführt wurden. Jede der neun Proben wurde Drücken unterworfen, die mehr als 80% der einaxialen Druckfestigkeit des Granites entsprechen. Diese Drücke wurden für verschiedene Zeitspannen von wenigen Minuten bis zu einigen Monaten auf einem konstanten Niveau gehalten. Während der gesamten Langzeitbelastung wurden akustische Emissionen aufgezeichnet, um die Entwicklung und gesamthafte Beschädigung der Proben durch Sprödbruch aufzuzeichnen. Entsprechend bisher veröffentlichter theoretischer Vorhersagen, Feldversuchen und auch experimentellen Resultaten von Kriechversuchen an Granitproben wäre ein Versagen der Proben zu erwarten gewesen, wenn sie über längere Zeit einer Last von 70% ihrer einaxialen Druckfestigkeit unterworfen werden. Wider Erwarten trat bei sechs der Proben kein Versagen ein, als sie mit über 80% ihrer einaxialen Druckfestigkeit über mehrere Monate belastet wurden; daher wurden sie im Anschluss bei einaxialer Kompression zum Versagen gebracht. Die mittleren Festigkeiten der im Langzeittest verwendeten Proben sind vergleichbar mit den normalerweise für diesen Gesteinstyp angegebenen Festigkeiten. Drei der neun Proben versagten unter der Langzeitbelastung; diese drei Proben hatten eine erhöhte Endflächenreibung.

Jan 1, 2003

By Bjørn Nilsen, Brian J. Ballou

The Tellnes open pit mine in Southwestern Norway has been operating since 1960. The maximum height of pit walls is currently about 150 meters with the current mine plan extending this distance to 400 meters with slope stability being a major controlling factor. As a result of unfavorable combinations of directions of major joints and faults, local stability problems have occurred several places in the pits walls. Stability problems have affected the reliability of main transport roads on several occasions. Most of such incidents have occurred during heavy rainstorms and during periods of repeated freezing/thawing. This paper reviews some of the stability problems and the measures taken to deal with such stability problems.

Jan 1, 2006

The 96th Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room of the Transvaal Automobile Club in Johannesburg on Wednesday, 11th August, 1993. OBITUARIES The President announced the deaths of the following members of the Institute during the past year. Life Fellow E.F. Laschinger. Other Members R.K. Boright, J.S. Jacobi, R.D. Power, J.H. Cannon, C.J. du Plooy, L.B. Mcrae, C.P. Rossouw, A.L. Sillars, A.W. Heugh, R.K. Briggs, P.J. Stark, and C.S. Stott. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, all rose and observed a moment of silence.

Jan 1, 1993

By Q. Zhang, X. C. Wang, S. Mao

Phosphate ore is an important strategic mineral resource in which apatite is the main valuable mineral. Flotation is the most commonly used method to separate apatite from middle-low grade phosphate rock. Selective flotation separation is based on the difference of physical and chemical properties of minerals occurring at the three interfaces of mineral/bubble/water. Surface and interface chemistry of mineral have been playing an important role in interpreting and governing its flotation phenomenon. In-situ, visualized and high-precision analytical techniques, such as Time-of-Flight Secondary Ion Mass Spectrometry, Atomic Force Microscopy and Molecular Simulation, have been applied to explore and uncover microscopic nature of apatite flotation. Consequently, a great progress at molecular or atomic level on surface and interface chemistry of apatite flotation has achieved in the past decades. In this paper, the research progress of surface and interface chemistry of apatite flotation such as surface wettability, surface-charging characteristics, surface dissolution behavior, adsorption mechanisms of fatty acid collector and depressor on apatite surface were systematically reviewed. This review will be helpful for the development of more selective reagents and efficient technologies for apatite flotation. Keywords: Apatite, Flotation, Surface and interface chemistry, Surface analysis technology

Jan 1, 2020