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By Y. Rajpal

The Hedley and Grant pillar strength formula is widely used within the South African mining industry to calculate pillar strengths in bord and pillar mining layouts, and is currently being used at Bathopele Mine. Bathopele is an operation of Anglo American Platinum near Rustenburg, mining the UG2 reef at depths ranging from 40 m to 300 m below surface. The formula includes a parameter K, which is a downrated uniaxial compressive strength value of the rock, used to calculate the strength of a pillar. At Bathopele Mine, for the shallower areas Less than 150 m the value was 33 MPa, but this was increased to 44 MPa due to the fact that rock mass conditions improved and there were no incidence of failure in the shallower areas. Underground observations showed pillars to be stable with no signs of failure, and it was questioned whether the design was not still too conservative, resulting in sub-optimal extraction ratios and consequently a loss of revenue to the mine. A trial mining section was started at the mine where the pillars were reduced from 6 m x 6 m to 5 m x 5 m and the pillar behaviour was monitored for the onset of failure. Numerical modelling was conducted using the TEXAN code to back-analyse pillar stresses in order to find a more realistic value for K. Results from the trial section indicated that the pillar design was in fact too conservative, and the value for K was adjusted to 54 MPa for future designs. This paper details the findings from underground monitoring and numerical modelling results, and includes details for further calibration of the K value in order to further optimize the extraction of the orebody.

Jan 1, 2012

To be held from the 9th to 14th April, 1972, in Johannesburg, South Africa. GENERAL INFORMATION The first symposium in the series was staged by the University of Arizona in 1961. Since then Stanford University, Colorado School of Mines, Pennsylvania State University and the Society of Mining Engineers of the American Institute of Mining, Metallurgical and Petroleum Engineers have acted together with the University of Arizona as co-sponsors of the series. The 9th Symposium in 1970 was sponsored by the Canadian Institute of Mining and Metallurgy together with McGill University and Ecole Poly technique in Montreal. The 10th Symposium, the first to be held outside the North American continent, is being organised by the South African Institute of Mining and Metallurgy (with the Council for Scientific and Industrial Research and the South African Council for Automation and Computation) in close collaboration with the previous co-sponsors. OBJECTIVES Mineral ventures increase in scale and complexity. The planning and control of these projects requires more and more sophisticated techniques. The intention of the symposium is to pool and exchange experience and knowledge and also to discuss new and potential developments. The papers presented in the main sessions, which will extend over one week, will together indicate progress which has been made in the successful application of operations research, mathematical, statistical and computer methods in each of the various aspects of operation in the mineral industry. A coherent account will be developed by consideration, in consecutive sessions, of the stages through which mineral prospects evolve in the course of their life. Primary aims are thus to stimulate discussion in depth of previous applications, to highlight current trends and to provide guidelines for future developments. PARTICIPATION The intention is to bring together persons responsible for managing the various operations in the mineral industry and the workers engaged in the development of mathematical and computer methods relevant thereto. SYMPOSIUM TOPICS 1. Market Analysis-demand and supply trends, models of mineral markets, price prediction. 2. Exploration and ore reserve estimation--exploration strategies, choice of drilling and sampling patterns, quantification of geological information, geo-statistical analysis, ore reserve assessment. Storage and retrieval of associated data. 3. Project design and analysis-influence on viability and risk of capitalisation, scale and method of operation, processing, uncertainties in design premises. 4. Planning of operation-planning and scheduling of construction, of development and of depletion of ore reserves. Logistics, rock mechanics and ventilation. 5. Control of operations-financial, production, cost and quality control as applied to both mining and processing. Flow and processing of relevant information. CALL FOR PAPERS An invitation is extended to intending authors to submit a synopsis, in 200 to 300 words, of papers which would develop the themes outlined above. The Programme Sub-Committee will choose, on the basis of these synopses, some 20 to 30 authors who will be invited to submit papers. Selection will be aimed at the provision of a coherent structure. Other authors may be invited to submit short papers either as contributions to the primary papers or for brief discussion in ancillary sessions which will be scheduled to follow on the main sessions. The official language of the symposium will be English. DEADLINES Prospective authors must submit synopses of papers by ............end April, 1971 Authors will be informed of results of selection of papers by . . . . . . . end June, 1971 Manuscripts will have to be in the hands of the Editors by . . . . . . . . . end October, 1971 PRE-PRINTS Papers selected for presentation in the main sessions will all be pre-printed and distributed prior to the symposium. As many as possible of the shorter papers and prepared contributions will also be pre-printed. PROCEEDINGS All of the main and ancillary papers together with edited discussion will be published shortly after the symposium in a single volume. TOURS AND VISITS A choice of visits to relevant local undertakings on a day during the course of the symposium will be available to participants. These will include a deep level gold mine. A tour which will include mineral projects of interest and the Kruger National Game Park will be arranged in the week following the symposium. LADIES' PROGRAMME Arrangements will be made for the reception and entertainment of ladies. ACCOMMODATION Accommodation will be available at hotels convenient to the symposium venue. The cost of reasonable hotel accommodation in Johannesburg is in the range R5 to RIO (7 to 14 U.S. dollars) per person per night. All reservations and associated arrangements may be made through agents to be appointed by the organisers in due course. FEES AND COSTS Symposium fees will not exceed R70 (100 U.S. dollars). These will include registration, one copy of the published proceedings, a set of pre-prints of the main papers, teas and lunches during the course of the symposium, and the various official social events as well as the mid-week visits. Accommodation, travel and post-symposium tour charges are not included in this figure. FURTHER INFORMATION All communications should be addressed to: The Secretary, South African Institute of Mining and Metallurgy, Kelvin House, Hollard Street, Johannesburg, South Africa.

By T. C. Huber

The southern African region has a high concentration of mineral resources and supplies much of the world?s platinum demand. As a result, the international community watches South Africa to understand the impact of supply on global markets. An analysis of supply certainty and risk plays a key role in the future of growing demand in various sectors. The southern African platinum industry experienced substantial growth in the early part of the 21st century, resulting in bullish forecasts for growth during the period of 2000?2006. However, southern African platinum producers saw a significant drop in production over the following three years as a result of many dynamic factors in operations and the global economy. Between 2006 and 2009 there was a million-ounce shortfall between forecast and actual production. This was raised as a concern at the Fourth International Platinum Conference in 2010 by Stephen Forrest during his keynote address, specifically regarding the lack of understanding in the market of the causes of this shortfall and any action that was being taken to address them. This paper reviews publicly available information in the media and corporate reports and communications for the period January 2006 to December 2009. In addition, several interviews were held with key stakeholders in the industry to provide further perspective. The paper then highlights the main reasons that are reported to have affected the loss in production over the period and discusses the possible implications of the information that the mining industry does and does not disclose regarding platinum supply.

Jan 1, 2012

By E. Pothas, P. R. Jochens, L. B. McRae, D. D. Howat

SYNOPSIS The phase equilibria, viscosities and sulphur capacities of titaniferous slags were determined in the composition range of CaO = 30 to 0 per cent, MgO = 0 to 30 per cent, SiO2 = 19.69 per cent, AI.O. = 13.12 per cent and TiO2 = 37.19 per cent. The phase equilibria were determined by high temperature microscopy, the viscosities were measured using a rotating outer cylinder viscometer and the sulphur capacities were evaluated from the results obtained by equilibrating the slag in a gas stream of CO, CO2 and SO2. The behaviour of these titaniferous slags under reducing conditions was examined. Possible use of the slags for aggregate, or slag-cement, and the possibility of extracting the TiO2 are discussed. CONTENTS INTRODUCTION PHASE EQUILIBRIA VISCOSITIES DISCUSSION OF THE PHASE EQUILlBRIA AND THE VISCOSITY VALUES EFFECT OF REDUCING CONDITIONS SULPHUR CAPACITY DISCUSSION OF THE SULPHUR CAPACITY VALUES POSSIBLE USES CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES INTRODUCTION The latest phase in the exploitation of the mineral wealth of the Bushveld Igneous Complex is the erection of a plant by the Highveld Steel and Vanadium Corporation Limited near Witbank to produce steel and vanadium-rich slag from the titaniferous magnetites occurring in this rock formation. These titaniferous magnetites occur as segregations in the gabbro body and the TiO2 is mainly present within the structure of other constituent minerals but also occurs in smaller amounts as ilmenite and ulvospinel. The vanadium is thought to be present in the iron oxide phase due to isomorphous replacement of the iron. Until very recently, it was feared that the high titania content of these titaniferous magnetites would militate against their value as useful iron ores. However, the design of an integrated plant to produce both steel and vanadium-rich slag, and in which the iron-making process is conducted in submerged arc furnaces instead of in

By L. Cheng, Y. Liu, Z. Shen, H. Shang, Y. Li

The pre-concentration process of magnetic coarse particles can discharge waste rock or liberated gangue before milling, which is an effective means to reduce cost and increase the efficiency of the concentrator, but the weakly magnetic ore doesn’t have the effective separation method of coarse particle such as hematite, limonite, ilmenite and so on, Because the composite iron minerals contain both strong and weak magnetic elements, the pre-concentration process cannot be applied, or the existing pre-concentration process has problems of complicated configuration and high operation cost. By researching a new type of external magnetic separation technology, the pre-concentration process of composite iron ore was realised by single equipment, which can have a good recovery rate with simple arrangement. In this paper, the separation principle and structure characteristics of the external magnetic separator were researched, and the magnetic circuit characteristics of the external magnet were analysed. The laboratory tests of vanadium titanium magnetite were conducted, and the test results proved that the external magnetic separator can be applied for the pre-concentration process. The industrial application shows that a product of TFe 24.76% with 90.08% recovery, TiO2 10.10% with 91.78% recovery can be achieved from the feed of TFe 20.67%, TiO2 8.33%. Keywords: Coarse particle pre-concentration, composite iron ore, external magnet, magnetic separator

Jan 1, 2020

Four engineering products and three consumer products have received awards in the 1978 Shell Design Awards competition organized by the Design Institute of the South African Bureau of Standards. Norman Hanson Visiting Fellowship The Norman Hanson Visiting Fellowship, supported jointly by the National Development Fund for the Building Industry (inaugurated by the Building Industries Federation (8.A.)), the Institute of S.A. Architects, the Association of S.A. Quantity Surveyors, and the National Building Research Institute of the CSIR exists to finance fully or wholly visits by eminent authorities from overseas to South Africa for the purposes of seminars, informed discussions, consultation, and possible active participation in scientific, technological, and development projects of importance to the building industry.

Jan 1, 1979

By M. -H. Fillion

"Geotechnical stability analysis and design in open pit mines requires access to representative geological, structural, hydrogeological, and rock mass models. The quality and quantity of collected geomechanical data used to build such models can have significant implications in the design of safe and economically viable slopes. Data collection is a continuous process throughout the life of a mine. The process starts from exploration to conceptual/preliminary feasibility, feasibility, design and construction, operations (early production/late production), and mine closure.As geomechanical data is often limited at an early stage of a project, the estimated variability of the geotechnical factors may be larger than the actual data variability. This can potentially result in a conservative selection of the pit slope angle. Collecting additional geomechanical data at later stages of the mine development may contribute to reducing the uncertainty associated with the geotechnical properties and a steeper slope angle may be used for the design. This can result in significant economic benefits.This paper investigates the impact of access to new data over time, following a series of geomechanical data collection campaigns, on design decisions. This is illustrated by comparing the resulting slope design, at three stages of the mine project, at a South African open pit mine. To demonstrate this, a series of slope stability analyses were performed using limit equilibrium tools. For each project stage, the slope angle design was modified until a similar probability of failure of 5% or less was obtained. The corresponding factor of safety distributions for each project stage were then compared to evaluate the impact of collecting additional data on the resulting slope design.The results showed that data variability can differ significantly from one project stage to another. Data variability may be greater at more advanced project stages (i.e. a wider distribution of the factor of safety). Furthermore, the results showed that, even for the cases with greater variability, steeper slope angles were possible at more advanced stages for the proposed design requirement (probability of failure < 5%). In this investigation, as more data became available, the uncertainty associated with data variability could be sufficiently reduced to allow the selection of less conservative slope angles. This can be used as a managerial tool in developing data collection strategies and allocating the necessary funds, and can lead to important economic benefits to the mining operation."

Jan 1, 2016

By A. N. Brown

The Eighteenth International Symposium on the Appli¬cation of Computers and Mathematics in the Mineral Industries was held in London from 26th to 30th March, 1984. The Symposium was organized by the Institution of Mining and Metallurgy under the leadership of Mr M.J. Cahalan, Chairman of the Organizing Committee. The venue chosen was the Royal School of Mines, Imperial College of Science and Technology, in South Kensington. Some 300 delegates from all parts of the world attended, which included a delegation from South Africa that numbered about 20 persons. This extremely successful series of international meet¬ings was begun in 1961 in Tucson, Arizona, and has grown in strength and importance over the years. The arrange¬ment of the symposia is regulated by the International Council for APCOM under the Chairmanship of Professor R.V. Ramani (U.S.A.), the other current members being Professor J. Elbrond (Canada), Dr Thys B. Johnson (U.S.A.), Professor Young C. Kim (U.S.A.), Professor D.G. Krige (R.S.A.), Professor A.J. Lynch (Australia), Professor C.T. Shaw (U.K.), Dr A. Weiss (U.S.A.), and Professor F.L. Wilke (F.R.G.). There is no doubt that the enthusiasm and dedication of this small group of people and the excellent working relationship that exists between them are responsible for the continued success of APCOM meetings.

Jan 1, 1984

By H. C. Van Der Merwe

In the 21st century, dynamic, accurate digital 3-D geological models are essential to the pursuit of safe, efficient and profitable mining. This is particularly true for the deep-level underground mines in South Africa. The Sirovision® solution is a collaboration project between the Australian CSIRO (Commonwealth Scientific and Industrial Research Organisation), Datamine Software Ltd. and AngloGold Ashanti Ltd (AGA). The purpose of the project is to provide a fully integrated digital rock face imaging, geological mapping and modelling system for the AGA gold mining operations. The CSIRO-developed Sirovision® Stereo Camera Rig (SCR) consists of two digital cameras, alighting system, a laser guidance system and image processing software. The imaging system works on the principles of photogrammetry, i.e. overlaying of two 2-D images with a central focus point, with mathematical algorithms extracting 3-D information from the 2-D image pair. The output from matching several image pairs is a computer-generated, full 3-D, virtual copy of the mining excavation. The image resolution and relief ares of sufficient quality to distinguish different rock types and structural contacts. Functionality within Datamine Studio3 is used to add geological intelligence to the 3-D images provided by Sirovision®. The geologist identifies and ?draws? lines representing geological features directly onto the image. By utilizing the inherent ?topography? of the 3-D image, the software is able to convert the lines into 3-D surfaces, ready for use in the 3-D geological model. Subsequent to promising underground test results from AGA?s Sunrise Dam Gold Mine (SDGM) in Australia and other mining operations worldwide, it was decided to test the Sirovision® system in the South African deep-level gold mines. The first underground tests at Moab Khotsong Mine began in January 2009. The objectives of these tests entailed the capturing of 3-D images of selected development ends, mapping of geological features onto the 3-D images and integration of the mapping data with the 3-D geological model. Some downsides have cropped up during the feasibility testing, related to practicality of the SCR for acquisition of 3-Dimagery in the deep-level underground operating environment. These constraints will have to be addressed prior to operational implementation. Facing such difficulties is not unusual when attempting to implement new technology in such a challenging working environment and testwork is still in progress at the mine in order to prove the concept of using this technology in a Witwatersrand underground gold mine. The great advantage of the Sirovision® solution is that it offers the geologist the opportunity to work remotely on a 3-D virtual copy of a mining excavation, without the heat, humidity, hazards and time constraints associated with physical mapping in an underground workplace.

Jan 1, 2009

[Consider a square block W in an ore body S2, to be valued from one centre sample w, and one corner sample w2 (Fig. 9.1). The sample set is ws = Iw,;w21. We can estimate the block average µw by the average of the sample values x, and x2: µw = &apos;z (x, + xz). (9.1) The error made is measured by the estimation variance: o&apos; (ws to W) = 2 - (ws; W) - - (ws;ws) - - (W; W). (9.2) However, we know that the centre sample w, gives more information about the block value than the corner sample w2. In the example studied in § 8.4, where w, and w2 were considered to be points, we found that of (w, to W) was nearly one third smaller than o2E (w2 to W), therefore when estimating W one should give more weight to w, than to w2. In general, when evaluating a block W from a set of n samples ws, where WS = l w;w2; ... wn1, a better estimator of µw can be obtained if we give different weights to the sample values, depending on the size and the positions of the samples. Some desirable properties of such an estimator µw are: ? It should be a linear function of the sample values xi: n µw = bi xi (9.3) =t where bi = weight given to sample x . ? It should be unbiased, i.e. its expected value should be equal to the true block value: E [µw - µw] = 0. (9.4) ? The mean squared error of estimation of µw should be a minimum E [(µw - µw)2] = a minimum. (9.5) The estimator which satisfies these properties is a minimum variance, linear and unbiased estimator, and is known as the kriging estimator. The corresponding error of estimation is the kriging error. This estimator is also known as the BLUE (for Best Linear Unbiased Estimator) estimator. This was named by Matheron in acknowledgement of the early work of Krige&apos;s in the optimization of the evaluation of the South African gold mines. The following notations will be used: µK kriging estimator. o2k = o2K (w,, to W) kriging error.]

Jan 1, 1978

By C. E. More

Some observations on &apos;ancient&apos; mining at Phalaborwa C. E. MORE. B.A. (Pretoria) (Visitor) A brief account is given of historical references to the Phalaborwa area, the first being to the mountain of copper and iron sought by Francois de Cuiper in 1725. These are followed by a description of several finds in the area, which are related to finds described in the literature and to Bantu tradition on the subject. Phalaborwa is one of the earliest known mining sites in the Republic of South Africa, Loolekop having been a mining centre, as shown by carbon-14 dating, since 770 A.D.

Jan 1, 1974

By E. Matinde

Human beings have been dependent on metals and alloys for livelihoods since time immemorial. In fact, there is irrefutable evidence that successful ancient civilizations achieved supremacy over their environments through the mastery of metals and alloys (Miller, 1995; Mtetwa, 2022). Over time, metals and alloys have evolved to become ubiquitous engineering materials indispensable to mankind, with applications in industrial and residential infrastructure, agriculture, energy generation and storage, transportation and communication systems, and manufacturing, among others (Elshkaki et al., 2018; Watari et al., 2021). Population growth, technological developments, and increase in urbanization and industrialization are all intricately linked to the intensity of use of metals and alloys. With up to 5 billion people estimated to live in urban areas by 2030 (Armstrong, 2009), the demand for metals and alloys will inevitably increase in order to satisfy the increased demand for infrastructure, machinery, and other human needs (Elshkaki et al., 2018; Watari et al., 2021). According to LePan (2022), urbanization and growth of mega-cities will increase the demand for metals and alloys, such as nickel, steel, aluminium, and copper by 116%, 50%, 57%, and 26%, respectively, between 2019 and 2035. Naturally, the production of metals and alloys from natural ores, secondary resources, and/or a combination of both, to meet this increased demand will invariably lead to the increase in generation of deleterious emissions in the form of wastes. In fact, mining and metallurgical wastes currently constitute the world’s largest anthropogenic streams by mass, often containing a high concentration of elements and compounds that can cause potential damage to natural ecosystems and humans (Hudson-Edwards et al., 2011; Lottermoser, 2011; Matinde et al., 2018; Seetharaman et al., 2022). Obviously, society’s heavy reliance on new mineral resources to drive the emerging energy transition entails that the legacy of these waste streams will continue unabated for the near-foreseeable future. The scarcity of high-grade mineral reserves, coupled with deliberate efforts to solve the anthropogenic circularity conundrum, therefore introduces a high level of urgency in the metal extraction industry to develop nascent and more eco-friendly processes and technologies. Integrating circular economy principles based on intentional configurations of circular industrial ecosystems in order to maintain the value of materials and resources in the economy for as long as possible is widely accepted as a practical approach to mitigating the negative externalities imposed by

Sep 1, 2024

A Special General Meeting, followed by the February General Meeting of the Institute, was held in Kelvin House, Johannesburg, on 18th February, 1970, at 4.30 p.m. Mr J. K. E. Douglas (President) was in the Chair. There were also present 24 Members: Messrs A. R. C. Fowler, R. C. J. Goode, Prof D. D. Howat, Messrs D. G. Maxwell, J. A. Nixon, P. W. J. van Rensburg (Council Members), C. A. Border, J. C. Fritz, E. K. Gibson, P. L. Grimbeek, S. D. Hill, D. A. Immelman, P. J. Uoyd, M. Mrost, C. S. Macphail, D. G. Malan, W. D. Ortlepp, R. S. Pearson, A. J. H. Pole, Dr W. S. Rapson, L. W. P. van den Bosch, R. A. von Maltitz and Dr A. Whillier. Eight Associate Members: Dr M. I. Brittan, Messrs J. Brett, I. E. Clarke, C. L. de Jongh, W. B. Evans, D. Loubser, R. C. More O&apos;Ferrall and G. R. Still. One Graduate: Mr T. J. Kotze. One Student: Mr J. A. Cruise. Nine Visitors: including Dr N. G. W. Cook, Messrs M. D. Labuschagne, A. Nicoll, S. Sadowski, Dr A. M. Starfield and Dr H. Wagner. Secretary: Mr D. C. Visser. Total present: 45. SPECIAL GENERAL MEETING The President: "You will have received notices of the Special General Meeting and I declare it duly constituted. In keeping with the trend of overseas and local institutes, your Council recommends that we should change our membership classification as indicated in the notes of the meeting. The new grades are proposed to replace those presently in the Constitution and By-Laws. In terms of Clause 4.8 of the Constitution a special general meeting must be held for the purpose of considering and, if approved, adopting with or without amendments, the revision of the undermentioned clauses of the Constitution, which Council now recommends should read as follows. Clause 2.2 &apos;Corporate Members shall comprise the grades of Honorary Life Fellow, Fellow and Member&apos;, these being the equivalent of Honorary Life Member, Member and Associate Member. Clause 2.6. &apos;Non-Corporate Member shall comprise the grade of Honorary Fellow, Graduate, Associate and Student.&apos; Are there any questions in regard to this proposal? If not would someone propose that these clauses be amended and adopted?" Proposer: Mr A. J. Nixon. Seconder: Prof D. D. Howat. The motion was then adopted. The President: "It is recommended that Clause 2.15 should read, &apos;A Corporate of the Member of the Institute shall be entitled to use the following authorised letters designating the grade of Membership in Honorary Life Fellow and Fellow, F.S.A.I.M.M. and Member, M.S.A.I.M.M.&apos; Previously we used the letters M.S.A.Inst.M.M. and your Council considered that we should adopt the simpler lettering. Could I ask someone to propose that this amendment be adopted?" Proposer: Mr R. C. J. Goode.

A new branch of the Institute-the Zululand Branch- was formed at the end of last year. After many months of preparation and perusal of address lists, it was realized that branch serving our members north of the Tugela was long overdue. A small steering committee consisting of Messrs John Selby, Dawid de Wet Smith, and Bill Kluckow got the branch of to a roaring start. They organized the inaugural meeting, which was held at the Richards Hotel in Richards Bay on 28th October,1993. Out of a possible 70 members residing in a 100 km radius, over half attended that first meeting!

Jan 1, 1994

Minutes of meeting held at the Moth Hall, Witbank on 13th November, 1969. There were present eleven members: Mr J. Meintjes (in the chair); Messrs I. E. van Aswegen, O. T. Wright, A. W. L. Brereton, A. Bain, J. Brook, P. J. Beukes, C. H. Coxon, B. F. v.d. Merwe, A. C. Hofmeyer, G. E. Carlyon. Six Associate Members: Messrs E. J. Jackson, J. N. H. Pritchard, R. E. Powell, W. Weber, R. Smith, B. T. Hosking. One Student Member Mr M. J. de Beer. Seven visitors. The Chairman reminded members of the intended visit to Barberton. Dr Stander, Director of the National Institute for Water Research, gave an interesting talk, illustrated with slides and a short film, on the conservation and reclamation of water in South Africa. After question time, Mr Hector, Witbank Town Engineer (visitor) thanked Dr Stander. The meeting closed at 7.10 p.m.

By A. de Souza

On Thursday, 6th February, 1992, D. Jan Visser, the Executive Director, NPI (National Productivity Institute), addressed the Productivity Breakfast of the SAIMM-Vaal Triangle Branch in Vanderbijlpark. The Breakfast was held at the Riverside Holiday Inn, and was attended by 50 senior and middle managers in organizations in and around the Vaal Triangle, as well as by Richard Beck, the President of the South African Institute of Mining and Metallurgy.

Jan 1, 1992

By S. T. Johansen, B. T. Løvfall, T. Rodriguez Duran

In this paper we develop a physics-based model for lining erosion in steel ladles. The model predicts the temperature evolution in the liquid slag, steel, refractory bricks, and outer steel shell of the ladle. The flow of slag and steel is due to forced convection induced by inert gas injection, vacuum treatment (extreme bubble expansion), natural convection, and waves caused by the gas stirring. The lining erosion takes place by dissolution of refractory elements into the steel or slag. The mass and heat transfer coefficients inside the ladle during gas stirring are modelled based on wall functions which take the distribution of wall shear velocities as a critical input. The wall shear velocities are obtained from computational fluid dynamics (CFD) simulations for a sample of scenarios, spanning out the operational space, and a model is developed using curve fitting. The model is capable of reproducing both thermal and erosion evolution well. Deviations between model predictions and industrial data are discussed. The model is fast and has been tested successfully in a ‘semi-online’ application. The model source code is available to the public at [https://github.com/SINTEF/refractorywear].

Apr 16, 2024

It is widely accepted that the type of grinding media has an impact on the grinding chemistry and subsequent flotation behaviour of the sulphide minerals being separated. There are countless laboratory investigations demonstrating that inert grinding media produces more oxidizing pulp potentials, reduced levels of grinding media corrosion products, and superior concentrate grades and valuable metal recoveries. However, taking these results to industrial scale has proved difficult. This paper provides details of the protocol developed and used during a high-chrome grinding media plant trial. It describes the test regime employed to measure changes in pulp chemistry as well as concentrate grades and recoveries to produce a statistically meaningful result. The work also highlighted the need for close cooperation between the metallurgists on site and the researchers conducting the trial. To demonstrate the protocol, data gathered during a plant trail in a PGM concentrate will be presented describing the changes in pulp chemistry and metallurgical response observed.

Jan 1, 2012

Falls of ground (FOG) still account for around 35 per cent of all fatalities in underground southern African mines. To help reduce FOG, appropriate support technology needs to be implemented, and a mindset and cultural change are required to make a significant change. Discipline plays a major role and needs attention, whilst appropriate first-world support technology is available to assist in the reduction of injuries and the improvement of productivity. Section 54 mine stoppages due to FOG are costly. Appropriate support should reduce these unnecessary stoppages. Coal mining has adapted leading support technologies over the years. Platinum and chrome mines have shown significant moves towards adopting leading and appropriate support technologies, seeing noteworthy changes in injury statistics for the better. In typical conventional underground mining operations, the use of temporary support components offers some protection to workers while the permanent and generally more elaborate support systems are installed or constructed. Nonetheless, FOG continue and still result in injuries to people. The author wishes to explore the options and practicality of making use of new-generation support products and technology to provide not only safer support operations, but to also enhance productivity at the working faces. This paper will examine the use of appropriate support technology as a means to making the working stope or development end a safer and more productive workplace.

Jan 1, 2012

By E Matinde, M. Mnisi, I. C. Thobadi, W. Clark, J. D. Steenkamp

Pyrometallurgical smelters utilise tap-holes, through which liquid metal, matte and/or slag are tapped at regular intervals. However, tap-hole failures can have a devastating impact on smelters, which includes loss of equipment, human life and business interruptions. Contributing factors to tap-hole failures include poor and/or incorrect refractory material selection, including tap-hole clays. The functions of tap-hole clays in smelters include their ability to be extruded and drilled with ease at the end and beginning of a tap, and their ability to resist chemical wear due to molten metal and slag during tapping. Mintek is currently developing methods of evaluating properties of tap-hole clays with a specific focus on workability, and wear mechanisms of clays due to ferrochrome alloy and slag. Of particular interest to this study was the characterisation of various tap-hole clays. This paper evaluates the chemical and phase chemical properties of three different tap-hole clays. The bulk chemical composition of the tap-hole clays was determined by inductively coupled plasma optical emission spectroscopy, proximate analyses and combustion methods. The bulk phase compositions and specific phase chemical compositions were studied using quantitative X-ray diffraction, scanning electron microscope and electron probe microanalyses techniques. Keywords: Tap-hole clay, chemical analyses, phase chemical analyses, ferrochrome

Jan 1, 2020