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VISIT TO HENDRINA POWER STATION AND OPTIMUM COLLIERY A visit to Hendrina Power Station and the Optimum Colliery, contractually committed to supply the coal for the power station, took place on the 20th September, 1972. INTERNATIONAL IRON AND STEEL CONGRESS This congress will be held in Dlisseldorf from May 23rd to 30th, 1974. The main theme is "Metallurgical Technology of Iron and Steplml1king".

By A. Haque

The shear behaviour of infilled joints produced from ordinary gypsum plaster (gyprock) and bentonite was investigated in the laboratory under Constant Normal Stiffness (CNS) conditions. Shear tests were performed on saw-tooth profiles having Joint Roughness Coefficients (JRC) of 4.75 and 9.25 under an initial normal stress (sno) of 0.30 to 1.10 MPa, and at a normal stiffness (kn) of 8.5 kN/mm. Test data under the same sno and infill thickness to asperity height ratio (t/a) were analysed for two different sets of JRC. The peak shear stress plotted against the t/a ratio under constant sno revealed an increase in peak shear stress with the increase in JRC, up to a t/a ratio of about unity. The effect of roughness on the peak shear stress was observed to be minimal when the t/a ratio exceeded 1.40. A mathematical model for the prediction of peak shear stress due to the increased infill thickness has been developed based on a hyperbolic stress-strain relationship and energy balance principles. The model predictions are in good agreement with the laboratory observations. Le comportement de cisaillement des joints remplis produits à partir de plâtre ordinaire et de bentonite a été étudié dans le laboratoire sous des conditions de rigidité normales constantes. Des essais de cisaillement ont été réalisés sur des profils en dents de scie ayant des coefficients de rugosité des joints (CRJ) variant de 4,75 à 9,25 sous un effort normal initial (sno) de 0,30 à 1,10 MPa, et une rigidité normale (kn) de 8,5 kN/mm. Le résultat des essais conduits sous la même contrainte et épaisseur de remplissage au rapport aspérité/hauteur (t/a) ont été analysés pour deux ensembles différents de CRJ. La variation de l'effort de cisaillement maximal contre le rapport t/a sous une contrainte normale constante a indiqué une augmentation de l'effort de cisaillement maximal avec l'augmentation du CRJ, jusqu'à un rapport de t/a proche de l'unité. L'effet de la rugosité sur l'effort de cisaillement maximal a été minimal quand le rapport t/a a excédé 1,40. Un modèle mathématique pour la prévision de l'effort de cisaillement maximal dû à l'épaisseur accrue du remplissage des joints a été développé sur la base de la variation entre contraintes hyperboliques et déformation et sur des principes de bilan énergétique. Les prévisions du modèle sont en bon accord avec les observations de laboratoire. Das Scherverhalten in mit gewöhnlichem Gips und Bentonit gefüllten Klüften wurde im Labor unter Bedingungen konstanter Normalsteifheit (CNS) untersucht. Scherversuche wurden durchgefürt für Sägezahnprofile mit Werten des Fugenrauhigkeitskoeffizienten (JRC) von 4.75 und 9.25 unter Normalspannungs-werten (sno) von 0.30 bis 1.10 MPa, und bei Normalsteifheit (kn) von 8.5 kN/mm. Testresultate für gleiche Werte von sno und Verhältnis Fülldicke zu Rauhigkeit (t/a) wurden untersucht für zwei verschiedene Werte von JRC. Die Beziehung zwischen maximaler Schubspannung und und t/a Verhältnis unter konstantem sno zeigte einen Anstieg der maximalen Schubspannung mit zunehmendem JRC, bis zu einem t/a Verhältnis von etwa 1.0. Der Einfluss der Rauhigkeit auf den Maximalwert der Schubspannung war minimal solange das t/a Verhältnis den Wert von 1.40 überstieg. Ein mathematisches Modell wurde entwickelt für die Vorhersage der Schubspannung die von zusätzlicher Fülldicke erwartet werden kann, ausgehend von einer hyperbolischen Spannungs-Dehnung Beziehung und dem Energiegleichgewichts-prinzip. Die Modellvorhersagen zeigten gute Uebereinstimmung mit den Laborbeobachtungen.

Jan 1, 2003

1. OPLEIDING IN INGENIEURSWERK VIR IN G ENIEURS- IN -OPLEID IN G 1.1 llegistrasie as Ingenieur-in-opleiding 'n Gegradueerde ingenieur wat in 'n eksamen geslaag het wat die Raad erkenl, is registreerpaar as 'n ingenieur-in-opleiding kragtens die Wet op Professionele Ingenieurs2. Aansoekvorms kan van die Registrateur verkry word. Mineral processing congress The XIIIth International Mineral Processing Congress is to be held in Warsaw from 4th to 9th June, 1979. Seeing that by products and co-products are becoming of increasing importance in mineral processing operations, the theme of the Congress is to be the 'Treatment of Raw Materials with Total Utilization of All Constituents'.

Jan 1, 1979

By M. Borowski, N. Szlazak, D. Obracaj

Methods of research and control of the intensity of gas inflow to undersoil layers, after the mines were abandoned are presented in the paper. Gas migration causes them to penetrate to lower storeys of buildings and earthen structures being a menace to people's health and life. The results of measurements of gas concentration in undersoil layers, gas emission to atmosphere and their accumulation in buildings on the territory of closed down mines are presented.

Jan 1, 2003

The response was good-one of the best the SAIMM has had to its various questionnaires. 231 replies were received from 2768 members representing a response of 8,35%. For fellows and Members together, the response was 13,7%. The spread of responses based on respondents' work situation appeared to be well balanced with some bias from those in consulting organizations. Members' perceptions of their employers' positions withrespect to environmental management looked somewhat optimistic, but it is encouraging to note that they reported that more than half were developing environmental management systems. Training of varying degree was taking place at al levels in their organizations. Members saw their Institute as an important agent inlifting environmental awareness, literacy and responsibility not only through the journal and symposia, but also by liaison with government departments and educational institutions. Most respondents saw environmental legislation both from local and overseas sources as affecting their organizations, their products and services with the emphasis on corporate image, core business and sales.

Jan 1, 1995

By S. Saeed, N. Coulson, P. F. Stewart

"The Mine, Health and Safety Act No. 29 of 1996, as amended, embodies worker self-regulation to advance health and safety in the workplace. An important provision for this is the Right to Refuse Dangerous Work (RRDW). This paper explores worker perspectives about the implementation of RRDW on South African mines against a backdrop of revised guidance in the sector: ‘Guideline for a Mandatory Code of Practice on the Right to Refuse Dangerous Work And Leave Dangerous Working Places’, gazetted in February 2016 by the Department of Mineral Resources (DMR). A mixed methods study conducted at mines (n = 14) included a survey of workers (n = 293), focus groups (n = 6) and in-depth interviews (n = 16). Workers reported a high level of awareness, a positive attitude, and experience of the formal RRDW. However constraints to the formal RRDW meant that informal worker resistance to dangerous work was commonplace. Evidence of informal non-confrontational consultation, cooperation, and collaboration in the event of a dangerous workplace also emerged between workers, and supervisors. The research underscores the importance of the RRDW and worker health and safety representatives to mine health and safety. The revised guidance addresses RRDW implementation gaps, but of concern is the potential partiality towards management interests. IntroductionEnsuring that mineworkers act on their duties and responsibilities for health and safety remains a concern across the globe. Article 13 of the International Labour Organization (ILO) Convention Safety and Health in Mines (176 of 1995) entrenched the Right to Refuse Dangerous Work (RRDW) as an important mechanism through which workers act in the best interests of their own occupational health and safety (OHS) and is considered a cornerstone of worker self-regulation (ILO, 1995). Countries ratifying Convention 176 are under obligation to make this right available to workers through OHS legislation that frames the circumstances, procedure, and protection of workers from discrimination in the event of a formal work refusal. The Convention has been ratified by 31 countries, with South Africa becoming a signatory in June 2000 (ILO, 2000). Worldwide studies show that workers use this right with caution (Hilgert, 2013) and cases associated with work refusal are rarely presented in court (Gunningham, 2007; Cooper, 2013). Rather, in cases of formal notification of a work refusal, issues arising out of this are addressed either in the immediate workplace or through the site OHS system and/or at industrial tribunals or similar mechanisms (Harcourt and Harcourt, 2000)."

Jan 1, 2018

By John Freer

As an innovation on the annual programme, the Excursions Sub-Committee organized a social get together of the Institute's Councillors and their families on Sunday, 27th February, 1983. Asian Mining - change of date The Second Asian Mining Conference, previously announced as being held in Manila, The Philippines, from 5th to 8th November, 1984, will now be held in Manila from 11th to 14th February, 1985.

Jan 1, 1983

By M. Steyn

This article captures the intrinsic differences of thermal coal products, their utilization and their substitution characteristics. South Africa produces approximately 245 million tonnes of coal annually. Eskom consumes 46% (approximately 112 million tonnes), 26% (approximately 65 million tonnes) is exported, and SASOL Synthetic Fuels consumes 18% (approximately 44 million tonnes) and a further 9% (approximately 22 million tonnes) is consumed by domestic users in various different industries. Marketing theory contributes significantly to understanding the importance of technical product and quality appreciation and comprehension, encompassing elements of price, distribution, and promotion. Coal product specification is determined by the inherent geology of a resource and the number of complex actions to market the product to a specific consuming market. Sampling, analyses, beneficiation application, and an array of parameters contribute to matching thermal coal products to the value-in-use it provides to the different markets and its consuming industries. Coal producer shave come under increased scrutiny since South Africa has been experiencing electricity shortages since early 2008. General misunderstandings were declared on public forums and in the media by both legislators and the South African public since a perception developed that South African coal producers are exporting coal that could be utilized by Eskom.

Jan 1, 2010

By David J. Haddock

On Wednesday, 6th July, 1988, 28 members of the Johannesburg Branch of The South African Institute of Mining and Metallurgy and their guests assembled at the Rand Refinery Sports Club, which is situated within the Refinery complex, to hear Dr Daniel Polnow, General Manager of the Refinery, give a very interesting lecture on the Rand Refinery Complex and its activities. Accounting for gold The South African Institute of Mining and Metallurgy will be holding a 3- or 4-day school in the third week of May 1989 on the topic 'Accounting for Gold'.

Jan 1, 1988

By J. Guerrero, O. Pavez, N. Toro, A. Nazer

In the 19th century, mining in northern Chile was of great economic importance. Today, the ruinsof the copper smelters and abundant fragments of refractory bricks from their furnaces remain. Therefractory materials have not been previously studied. the origin, physical and chemical properties, and compressive strength of 10 different samples of historical refractory bricks collected on-site were investigated. The characterization results showed that the bricks are silico-aluminous, unlike the magnesium-chromium bricks used by current foundries. It was determined that 90% of them were produced in the UK and 10% were manufactured in Chile. The phases present are mullite, quartz, cristobalite, and tridymite, and the chemical composition corresponds mainly to SiO2. The compressive strength of the historical bricks is similart to those currently used,. These results may contribute to the knowledge of the 19th century mining and metallurgical historical heritage of Chile and the UK.

Jul 5, 2023

By B. Genc, P. Malepfane

This study proposes a new approach to reduce the environmental impact during surface mining by improving environmental factors through the incorporation of carbon footprint into strategic mine planning. Two key variables were analysed by contrasting and comparing the baseline and optimised models generated. These variables include net present value, which helps determine the financial feasibility of the mining models and their carbon emissions. The variables were analysed by using linear regression, Spearman’s correlation, a P-value hypothesis, and an exponential decay test. Results show that at Mine A the projected net present value was 62% higher than when running a baseline model. Furthermore, the net present value from the baseline model portrayed a high rate of decay at 0.667 versus 0.118 from the optimised model. This indicates the baseline model’s sensitivity to long-term project timelines and fluctuating markets. The optimised method presents an opportunity to manage emissions during the high operational costs phases. It is represented by a 31% improvement in carbon emissions during the periods of high operational costs, whilst maintaining a positive net present value when compared with the baseline model. It was shown that the optimised model presents a better chance of achieving financial feasibility and balancing environmental impact, thereby ensuring that Mine A can align with the environmental aspect of economic, social, and governance principles through lowering the carbon footprint resulting from its hauling operations.

Jan 30, 2026

By M. Le Roux, Q. P. Campbell, N. Hughes

Water plays a significant role in minerals processing; this is especially true in coal preparation where water-based beneficiation is widely accepted and consistently delivering sharp separation efficiencies and high product yields. Although wet processing is favoured, the substantial process water requirement may prove this impractical and unsustainable in some parts of the world. Many coal-rich regions (including South Africa) have experienced severe water shortages. Coupled with the effects of drought, some countries experience freezing winters from which problems related to frozen process water and machinery may arise. Hence coal preparation practices will soon have to adapt, irrespective of the technical and economic feasibility offered by the currently employed water-based methods. As a result, extensive research into the development of dry methods for effectively beneficiating coal has progressed. This review paper intends to provide a collection of the relevant information pertaining to dry coal processing globally, and aid in understanding the applicability, performance, success or failure thereof. The methods available for dry materials preparation, with special regard to those applicable for coal beneficiation, are detailed in terms of principle, applicability, limitations and performance. Dry coal beneficiation has potential to aid the current wet-based methods with some considerations to possible limitations set forth by coal geology, application, product specification, particle size distribution, moisture, efficiency, capacity and cost. These methods may be established in future, especially in the arctic, arid and under-developed regions through new plant installations, expansions and small mines processing. Keywords: Dry coal processing, preparation, cleaning, beneficiation

Jan 1, 2020

By E. Isokangas

A mine is essentially a series of operations, including drilling and blasting, crushing, milling, flotation, and leaching, that are interconnected and therefore interrelated, with the performance of one operation affecting the performance of another. Optimizing each stage separately without considering the whole system often causes potential economic benefits and energy savings to be missed. However, the PIO methodology is a thorough approach which considers these individual process activities within the context of the whole process. The basic principle is to optimize the process as a whole, rather than each process step in isolation from the others. Metso?s Process Technology and Innovation (PTI) group offers a global consulting service for the mining and construction industries. A significant amount of this consulting work involves process integration and optimization (PIO) studies. When conducting a PIO study, every aspect of the process is considered. In addition to drilling and blasting, transportation, handling and storage, crushing, screening, grinding, flotation, separation, and recovery, other aspects including equipment utilization and energy consumption and even greenhouse gas emissions are also included if necessary. In a PIO project, it is very important to understand what type of material is being processed at any point in time. That is, which domain or domains is the material part of? This is necessary in order to observe the effect of different ore sources (and the blending of sources) on concentrator performance. Linking the ore from the pit to the concentrator required the development of an ore tracking system. As a result, PTI developed a radio-frequency based material tracking system called SmartTag?. This system allows tracking of ore from its source through blasting, run-of-mine (ROM) pads, crushers, intermediate stockpiles, and finally into the concentrator. Using the SmartTag? system, definitive correlations can be made between the performance of the plant and the plant feed characteristics, including the domain from which the feed ore originated. Since its commercialization in 2007, SmartTag? has been used in the majority of PTI?s consulting projects and several permanent systems have been installed worldwide1. Successful applications of the SmartTag? system have encouraged development to allow the system to be used in a wider variety of plants, in particular plants with finer crushing and screening stages. This paper describes how the SmartTag? system is being utilized by PTI and the benefits being gained by its use in PIO projects, as well as presenting some case studies.

Jan 1, 2012

By N. de Koker, Y Jooste, J. Gerber

This paper presents a novel application of the boundary element method for numerical modelling of the seismic activity and hazard that is associated with the shaft pillar extraction at Bambanani mine in South Africa. In the numerical model, the tabular mining excavations are represented by displacement discontinuity elements, and to accommodate crush, shear, and fault slip seismic events, the numerical model is populated with additional displacement discontinuity elements that represent modelled crush- and shear-type failures in the rockmass. Crush-type failures are evaluated by applying the limit equilibrium method and a Hoek-Brown strength criterion, and shear-type failures are evaluated by applying a Coulomb-friction strength criteria to Ortleppshear and geological features. In this paper, the modelling results are presented as time history analyses of modelled potency from 1 January 2010 to 30 June 2022 and normalised exceedance rates for different mining periods using an upper-truncated power law. The normalised exceedance rates of seismic events that have moment magnitude Mw ≥ 1.0 are lowest for the initial mining period (26 events per year) and highest for the final mining period (218 events per year). The relative errors of the modelled potency and normalised exceedance rates are typically less than 10% or 15%, which suggests that the modelling methodology is appropriate for medium- and longer-term forecasting of seismic activity and hazard, as presented in this paper. Shorter-term forecasting is not considered in this paper.

Nov 24, 2025

By C. Ntsele

Stirred milling technologies have firmly established themselves in concentrator circuits as energy-efficient alternatives to tumbling ball mills. High and continued increases in electricity costs, coupled with the ever-increasing power consumption by primary grinding circuits due to declining head grades of ore-bodies, provides a compelling case for these technologies. Additionally, the ability to successfully deploy stirred milling in coarse grinding applications extends the range of use in concentrators, thus increasing the opportunity matrix for energy optimization in a flowsheet. This paper therefore details methodologies and strategies that can be applied to evaluate the optimum stirred milling solution for different concentrator applications. These methods and strategies will focus specifically on the two major stirred mill machine types; namely, gravity-induced (VERTIMILL? grinding mill and Nippion-Eirich tower mill) and fluidized (SMD, Isamill?, Knelson-Deswik mill, etc. ). Finally, case studies from circuits across industry and laboratory tests will be used to illustrate the energy benefit from the use of stirred mills.

Jan 1, 2012

By M. Shamsi, M. Nehring

One of the most challenging aspects in semi-mobile in-pit crushing and conveying (SMIPCC) system design is determining the optimum depth at which to change from a purely truck-based haulage system to a conveyor-based haulage system. We used scenario analysis to determine the optimum transition depth between a truck and shovel (TS) system and a SMIPCC system. Traditional pit-limit algorithms were used to generate the final pit limit on a copper deposit, which was then divided into four pushbacks. The final operating pushbacks (phases) were designed for both TS and SMIPCC. The end depths for each phase are viewed as candidate transition points to switch from the TS to SMIPCC haulage system. Economic calculations were applied for five different scenarios, including adopting SMIPCC from the outset (pure SMIPCC), after the first, second, and third phases, and finally not using the SMIPCC system (pure TS) at all. The analysis indicates that the second scenario, at a depth of 335 m, results in the lowest cumulative discounted cost (CDC). In this case, the CDC is 17.6% lower than that for the pure TS scenario and 10.7% lower than for the pure SMIPCC system scenario.

Sep 1, 2021

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 P. O. Akinseye, F. T. Cawood

Mineral royalties are one of the oldest forms of mining taxation, and were initially introduced to extract economic rents from mining. Over time, the royalty regime has become more complex as it was identified as an important policy instrument that can achieve more multi-faceted outcomes. Such a multi-tiered approach in the use of the royalty instrument is also the case with South Africa. With South Africa’s new mineral royalty regime now in place for ten years, it is perhaps time to assess its impact and effectiveness. To carry out this assessment, an econometric evaluative study was undertaken using four major commodities in South Africa, namely gold, platinum, iron ore, and coal. The study explored five different policy options for government to consider and tested them to determine the most favourable one that will realize the regime’s policy objectives. After the assessment, two major options stood out. Hence, this paper seeks to highlight which of the two options is the most favourable for consideration by policymakers. Based on that study, we find that the current structure is effective, but also recommend that the factors in the formula for refined minerals be ‘modified’ to reduce the capped profitability ratio from the current 60% to 30% and the maximum royalty rate for refined minerals from 5% to 3%. The minimum rate of 0.5% during times of depressed mineral prices and no or low profitability will not be affected.

Dec 1, 2021

By K. Thambi

The court in Baleni v Minister of Mineral Resources [2019] 2 SA 453 GP and [2020] 4 All SA 374 (GP), deliberated on the protection of rights of a community holding informal land tenure under Customary Law. The contention related to the necessary level of consent needed to acquire a mining right over such land. Moreover, whether consultations with such communities (Section 23, Mineral and Petroleum Resources Development Act 28 of 2002 (MPRDA) or consent (Section 2, Interim Protection of Informal Land Rights Act, No. 31 of 1996 (IPILRA)) was required to acquire such right. The case has a significant bearing on the granting of mining rights in South Africa, and the discretion of the Minister of Mineral Resources (the Minister) in this regard. However, the objectives of the MPRDA and IPILRA do not dovetail, therefore consultation and consent are not mutually exclusive (Tlale, 2020). This note argues that, despite the resounding victory of this case, the peripheral basis surrounding the decision and the various levels of engagement require serious deliberation. Equally, the degree of reliance on the IPILRA requires clarity to avoid aborting the fundamental objectives of the MPRDA. This paper provides considerations and recommendations that may reduce or eliminate the tensions between the statutory and socio-economic rights in the application of the two statutes.

Sep 1, 2022

By S. K. Murphy

A partial shaft pillar extraction project was embarked on at a mine in the West Wits mining region in South Africa. Prior to the extraction, a rock engineering assessment was conducted with the main objective being to establish which areas of the shaft pillar could be extracted without unduly affecting the stability of major infrastructure within the shaft pillar. Standard numerical modelling methods were used to conduct this assessment and several areas were identified for extraction. However, during the extraction process, it was found that the infrastructure was affected more than was originally predicted by linear elastic modelling. In addition to this, several large events resulted in far more large aftershocks than would normally be predicted. In order to gain an understanding of this phenomenon, seismic data was integrated with numerical modelling as follows: > The seismic data in the form of displacements was integrated in 3D space within the model to assess the effect of static stress changes associated with seismic activity > Data from large events was integrated onto specific structures, where displacements associated with large events were integrated onto the plane of structure in question. This paper describes the methodology and results obtained from each of the above processes and include insights into the mining process that were previously unfathomable using standard linear elastic numerical modelling. The way forward for this rock engineering assessment of partial shaft pillar extraction is also discussed.

Jan 1, 2012