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A Colloquium and General Meeting was held jointly with the Mine Ventilation Society of S.A. in Kelvin House, Johannesburg, on 17th November, 1971, the theme being "The Economics of Mine Ventilation". Professor D. Howat (President) was in the chair. The Colloquium was attended by 150 delegates and was opened by the President at 9.00 a.m. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the 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: Fellows: Frederich-Wilhelm Volk, Peter Bennet Columbine. Members: Allan Colin Lawrence, Karel Anton van Gessel, Christopher Robert Harrison, Christopher Michael George Wartley, Frank Heinrich Deist, Ralph Morris, Benjamin Johannes Nolte. Associates: Wolf gang Freidrich Gottsman. TRANSFERS From Member to Fellow: Hugh Edward Keith Alien. From Graduate to Member: Errol Vincent Bosman, Christopher Roderick Stewart Needes, Bernard Wessels Holthousen. From Student to Graduate: David Robert Fleming. I welcome the new members to the Institute and congratulate them on their election. CO-OPTION TO COUNCIL The President announced that at the Council meeting held on 5th October, 1971, it was agreed, in terms of Rule 3.9 to co-opt Dr T. B. Beeton to Council. COLLOQUIUM The President welcomed visitors and members. He stressed that the discussion would be informal and that any contributor requiring publication should submit his contribution in writing. He then thanked the authors for providing pre-prints of the papers. After the President had concluded his opening remarks, he asked Professor J. de V. Lambrechts to act as Colloquium Chairman for the day and he, in turn, introduced the three Session Chairmen namely, Dr A. Whillier (Chamber of Mines and President of the Mine Ventilation Society); Mr M. Barcza (Managing Director, Corner House Laboratories); and Mr L. W. P. v.d. Bosch (Chief Consulting Engineer, Union Corporation). The following papers were presented: "Fan efficiency investigation on mines of the Union Corporation, Ltd." by J. A. Drummond. Published in the Journal Feb. 1972. "The design of underground cooling towers" by A. Whilliel'. Published in the Journal, Oct. 1971. "Some aspects of the design of cooling plant installations" by R. Hemp. Published in the Journal, Nov. 1971. "The planning of ventilation and refrigeration requirements in deep mines" by D. F. H. Grave and R. M. Stroh. Published in the Journal, Dec. 1971. "Cooling power of underground environments" by D. Mitchell and A. Whillier. Published in the Journal, Oct. 1971. At the conclusion of the three technical sessions the Symposium Chairman commented as follows, indicating that he would prepare a written summing up at a later stage: "The tone of the colloquium has had a sincerely practical note about it. It would have been a pity if the ventilation experts talked only theory and little practice. This practical theme has, I am sure, made the colloquium interesting to both ventilation men and others whose daily tasks do not touch so closely on this fascinating subject. This practical theme was in evidence through all the papers and contributions. Some of you may have felt that there was not enough emphasis on the word 'economics' as advertised in the broad title of the colloquium. I do not think this was really a valid criticism because as someone said 'it all boils down to Rands in the end!' So whether it was a case of low fan efficiency, poor design of cooling towers, wrong planning or low human efficiency due to high heat stress. . . it all boils down to money saving and therefore economics, whenever improvements are forthcoming. The title of the colloquium was thus not misplaced. The views of senior mining men on the production side are appreciated. Let us say that this exchange of views between ventilation engineers and those who have to take the final decisions and spend the money, should prove to be most rewarding." Professor Lambrechts finally thanked the Session Chairmen and everybody who had helped to make the colloquium a success and the meeting closed at 4.0 p.m. In a subsequent written summing up, the Colloquium Chairman gave the following as his impressions of some of the highlights which emerged from the papers and discussion thereof: (The names indicate the authors only). Drummond: It was hinted that the time had arrived to consider the introduction of a South African fan test code which would be better suited to local conditions than the currently acknowledged B.S.S. code which, however, is seldom enforceable in practice. In this connection also, there was prominent reference to the thermodynamic approach of McPherson. Wide variations in the quality of maintenance of, and repair work on, fans were stressed. It was mooted that ventilation engineers responsible for estimating the basic duty specifications for large fans, frequently played safe by overestimating the pressure required, thus ensuring that there would not be a shortfall in air volume delivered. This usually meant reduced fan efficiency and it was suggested that decision makers seemed to lay more emphasis on volume of air delivered than on real eco-

By R. J. Durrheim, B. Manzunzu, V. Midzi

Selecting ground motion prediction models (GMPM) is crucial in assessing seismic hazard levels in a specific region. This study investigates the influence of ground motion model (GMM) selection on seismic hazard assessment in Johannesburg, South Africa. Most seismic events affecting Johannesburg are related to mining activities and water ingress into the underground mine voids. The most seismically active regions in South Africa include areas around Klerksdorp, Welkom, and Carletonville. These regions experience a significant number of earthquakes, with mining activities being a major factor contributing to seismic events. Ten ground motion prediction equations were selected from regions of similar tectonics setting and were assessed to see if they correspond to the available local data. Six of these were also compared to the ground motions produced by the earthquake of 14 August 2014, which occurred in the Orkney area, one of the mining areas in South Africa. Sensitivity analyses were also carried out to assess the influence of ground motion prediction equations (GMPE) on the seismic hazard of Johannesburg. The results indicate that the choice of GMPM significantly affects the estimation of seismic hazard levels in Johannesburg. Different GMM can lead to varying ground shaking intensity predictions, impacting risk assessments and engineering design considerations. The findings highlight the importance of carefully selecting appropriate GMM tailored to Johannesburg’s specific geological and tectonic characteristics. Understanding how different models perform in this region is essential for accurate seismic risk mitigation strategies.

Jan 12, 2025

By A. R. Javadi

Pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS) and galena (PbS) generate hydrogen peroxide (H2O2) when placed in water, with pyrite generating the most amount of H2O2. The order of these minerals for generating H2O2 in water is: pyrite > chalcopyrite > sphalerite > galena. In previous research, the methods of generation of H2O2 in the grinding mill were studied. In this study, data from experiments were included by using MODDE 9 software for six parameters composed of water, grinding media, particle size; adding collector to the grinding, and adding depressant and pH. Finally the optimal condition was achieved. According to the results, most of the recovery is related to the particle 75 μ size and when using processed water, adding 100% collector and without depressant and pH 10. The most recovery of lead in the case of the use of fresh water is in the case of 100% collector, without depressant, pH 10 and 150 μ particle size. Maximum recovery in fraction size 45 μ in the case of water process is 100% collector, without depressant and pH 10. Maximum depressant of pyrite will be the fraction size 75 μ, distilled water, without collector, 100 depressant. Keywords: Sulfide mineral, hydrogen peroxide, flotation, oxidation

Jan 1, 2020

By D. K. Weatherley, T. P. Oladele, L. B. Bbosa

Comminution is a critical stage of mineral processing which aims to reduce the size of ore particles through breakage, consequently increasing the likelihood of liberation of valuable minerals. Several factors, such as pre-existing cracks, mineralogical composition and particle size, are known to affect ore breakage behaviour. While investigating the contributing role of each factor is essential to improve understanding of breakage, isolating individual factors by experiment is typically impractical. Numerical techniques such as the Bonded Particle Model-Discrete Element Method (BPM-DEM) have been developed as a means of studying closely controlled breakage conditions. This study evaluates this technique in modelling the effect of pre-existing cracks breakage behaviour for synthetic ore specimens during impact breakage in a short impact load cell (SILC). Synthetic ore was modelled as a collection of discrete entities connected by brittle-elastic beams. Model parameters were calibrated against macroscopic material properties of a conventional homogenous synthetic ore. The extent of pre-existing cracks within specimens was prescribed by varying discontinuities between the connecting entities. An approach with the insertion of seed points was used to model the mineralogy of the specimens. Results showed that pre-existing cracks resulted in a decrease in the fracture force as the crack density increased. Additionally, the irregularity of fracture patterns within rock specimens after impact became more apparent as the crack density increased. The findings were used to emphasise some of the attributable causes of the variation observed between ore hardness characterisation tests and in situ ore behaviour. Keywords: Element Method; Bonded Particle Model, synthetic rock sample; rock fracture, preexisting cracks

Jan 1, 2020

By M. Pierce, E. Karampinos

"One of the main challenges in the numerical modelling of ground support in underground excavations is to reproduce the performance of the sequential installation of the reinforcement while capturing the rock mass behaviour of an advancing face in 3D. The 3D modelling approaches used to simulate the progressive advance of excavations are mostly continuum and often cannot reproduce the rock mass failure mechanisms. The 3D discrete element method (DEM) can better reproduce structurally controlled rock mass failure mechanisms and can explicitly represent the reinforcement elements. This paper builds on previous work that reproduced the structurally controlled squeezing conditions in an underground hard-rock mine using 3D DEM and the in situ behaviour of reinforcement under pull conditions. It addresses important issues on the way reinforcement is explicitly introduced in discrete element models. A pseudo-3D model is employed to overcome the computational restrictions and time limitations of a 3D modelling approach. The work focuses on the scaling of the material properties of the ground support elements when the thickness of the model is not equal to the out-of-plane spacing of reinforcement. It demonstrates the scaling methodology based on the type of the modelled reinforcement elements used and investigates the significance of this approach. The advantages and disadvantages of this approach with respect to 2D and 3D methods are discussed. The results are compared with field data and previous modelling work done at the mine. IntroductionNumerical models can provide significant insight into the anticipated behaviour of underground excavations. The modelling of ground support, however, is not a trivial exercise. An effective representation of ground support in underground excavations should capture the behaviour of both the rock mass and the support elements. When numerical models are used for design purposes, the complexity of the problem requires significant time and expertise (Sweby, Dight, and Potvin, 2016).At a laboratory scale, numerical models have successfully reproduced the results of laboratory tests on rockbolts by explicit modelling of the bolt, the borehole, and the grout. Chen and Li (2015) used a continuum FLAC3D (Itasca Consulting Group Inc., 2012) model to simulate the mechanical behaviour of D-bolts as observed experimentally. Grasselli (2005) used a 3D finite element code to model the behaviour of fully grouted rods and expandable bolts under shear."

Dec 1, 2018

By F. Diot, S. K. Tripathy, L. O. Filippov, I. Filippova

Among different pre-treatment methods, a high voltage electric pulse was recently developed and is gaining popularity due to multi-benefits such as pre-weakening along the grain boundaries, as well as size reduction to improve the liberation characteristics. In this paper, the pre-treatment using high voltage electric pulse of lithium-bearing granite ore was studied to understand the morphology through texture, as well as the friability of the particles. To understand the phenomena, SELFRAG, a laboratory facility used for generating high voltage electric pulse and key operating variables were varied. The role of applied voltage (94.5-195.5 kV), number pulse (3-87), and the frequency of pulse (1.3-4.7 Hz) was varied to understand the liberation characteristics as well as energy consumption. Characterisation tools such as optical, and electron microscopy were used to describe the pre-weakening phenomena through textural features. Further, the energy required to break the particle to finer sizes as well as friability were determined and described. Keywords: Pre-treatment, high voltage electric pulse, lithium, liberation, grinding

Jan 1, 2020

By J. O. Claassen

"Homogeneous populations are required to perform descriptive, probabilistic, and inference statistics and to support stable, predictable mining operations. The geological and downstream processing environments are, however, highly heterogeneous. The complex nature of mining environments requires means to identify and define multipopulation environments that could affect the performance of mining value chains. A study performed at several operating mines suggests that the impact of heterogeneous or variable geological, mining, and plant processing environments on overall mining value chain performance may not be a key focus area at these operations. This was illustrated through the use of basic and spatial statistics, which included the log-probability plot, a modified range equation, and chronovariography. The findings reflect high relative variability in the geological and processing environments studied and mining operators’ inability to effectively deal with the sources and consequences of variability. The study suggests that a focus on heterogeneity in complex mining operations may significantly enhance overall mining performance. IntroductionHeterogeneity and why it mattersHeterogeneity refers to a state or quality of being variable/diverse and comprising different non-compatible elements or parts. In statistical terms a heterogeneous population can refer to a population comprising different non-compatible sub-populations or a multipopulation environment. The latter is commonly found in natural environments such as geological environments (Bardossy and Fodor, 2001). The inherent heterogeneity of complex geological environments is also referred to as spatial heterogeneity. Heterogeneity or variability, however, also occurs over time at mining operations. A case in point is variable ore composition on a conveyance system feeding a processing plant or product stockpile.Heterogeneity associated with the mining environment can significantly influence key aspects of day-to-day mining operations such as sampling, the use of descriptive, probabilistic, and inference calculations, and an operation’s ability to manage and control the mining value chain as a whole."

Jan 1, 2016

By L. Pretorius, S. Uludağ

This paper explores how to apply system dynamics principles to surface mining problems towards understanding the consequences of mining efficiencies. Some simulation examples related to machine and people performance have been used to demonstrate systems engineering concepts to mining engineers. The simulation tool used is Vensim, which is widely used in industrial engineering applicable to systems thinking, and systems dynamics. The science and mathematics behind the system dynamics as well as benefits and typical challenges are discussed to explore the applicability to mining problems. The benefit of having one less drill is easily quantifiable with the developed model which is one of many other measurable benefits, using the developed model. Some of the benefits of the improved quality of drill holes are not fully quantified as this depends on the mine specific inputs. There are examples of quantifying this in the other industries using system dynamics tools.

Sep 1, 2021

By D. H. Diering

Definition of mineral resources and reserves forms the basis for effective mine planning and reliable public reporting of mineral assets. Historically the mineral resource and reserves declaration process has been the domain of the geology and surveying disciplines, with the declaration of the reserves by the surveyor being based on the application of modifying factors to the declared resources available for mining. As part of an ongoing process to improve efficiency, reliability, and reproducibility of results, this approach has been revised and enhanced through the introduction of a revised process and reconciliation tools. The revised approach to reserve definition is based on the definition of scheduled resources, at an appropriate confidence estimate in the context of an approved business plan, over the anticipated life of the mineral asset being applied to define reserves. This planning and scheduling is developed, during the annual business planning process, by the mine planning department using tools such as CADSMine?. The scheduled area together with the application of revised modifying factors is tabulated in the BME (basic mine equation) and reflects the mine production plan over time. Simplification of the modifying factors to dilution and losses underpins the simple yet robust approach to improved definition of reserves in this process and in the basic resource to reserve equation (BR2RE). Dilution intrinsically affects grade but not metal content, whereas the losses reflect both the efficiency of mining and planning and are reflected in metal losses, area losses, or both. Reconciliation of the derived ?resource converted to reserve? area, (which is based on the business plan from CADSMine?), versus the ?resource available for mining?, (which is derived from Datamine?), underpins the robustness and auditability of the reserves declaration. This R&R accounting and reconciliation approach is transparent and facilitates interrogation of the logic and rationale of long-term business planning and project strategy. These numbers are processed and reported in the logic of the basic resource equation (BRE), which also addresses aspects such as white areas (future and historic), tail management, and partial extraction (non-scheduled pillars, etc.) in compliance with SAMREC definitions. Areas that do not have the necessary confidence and data support to be declared as resources find their space as pre-resource (outside the domain of public reporting), outlining existing potential for future extraction and reporting. Use of the BRE leads ultimately to a complete, refined accounting and reconciliation-oriented approach for all production entities. The revised resource and reserve process includes the discipline of mine planning as intrinsic to the definition and declaration of resources and reserves. Subsequent to the change in process, the resources and reserves have truly become the domain of the mineral resource management discipline. This paper defines the logic of the basic resource equations and outlines their application in the definition and reconciliation of mineral resources and reserves at Anglo American Platinum Limited.

Jan 1, 2012

By Y. Yang, L. Li, X. Liu

Coal mining in China is facing the transition from output to quality. Based on the total mining capacity and average production, the current situation of coal mining at mine, city, and province levels is analysed, and data in support for the layout of sustainable mining development and the optimization of output provided. The results show that 87% of China's coal is mined by underground methods, with an average production capacity of 0.93 Mt/a per mine. Open pit mining accounts for 13%, with an average mine production capacity of 5.73 Mt/a. The average mining capacity of coal mines in China is 1.05 Mt/a, with 1181 coal mines with an average capacity less than 0.3 Mt/a, accounting for 35% of the total coal mines but contributing only 4.51% to output. They are distributed in about 48 cities in six provinces, seriously restricting the transition to green coal mining. The coal industry should speed up the closure of small coal mines in key provinces and cities, eliminate outdated production capacity in the central region, increase the speed and proportion of coal resources moving westward, and promote high-quality development of coal mining.

Jan 26, 2023

By G. Akdogan, S. M. Bradshaw, M. I. Isaacs, P. Van Wyk

In the mineral processing industry, Ni-Cu-Fe-S converter matte is leached in order to remove base metals from a concentrate containing platinum group metals (PGMs). This paper investigates the atmospheric leaching process, in order to develop a better understanding of the leaching behaviour of the base metals; in particular Cu, Fe, Ni, and the PGMs in particular Ru and Ir with key process variables, acid concentration, copper concentration under oxidative leaching conditions. Higher initial acid concentration resulted in a higher copper, iron and nickel extractions, as well as higher leaching rates together with faster Cu, Ru, Ir precipitation occurring. On the other hand, a higher initial copper concentration resulted in more nickel but less iron being extracted. Keywords: PGM, converter matte, leaching, precipitation

Jan 1, 2020

Visit to the Modderfontein factory of A. E. & C. I. Ltd 23rd November, 1972 A full programme was arranged to suit both the mining and metallurgical sections of the Institute. After refreshments were taken and visitors welcomed by the factory management we were split into two groups, viz metallurgical and mining. Book review Stress-relief Heat Treatment of Vanadium Steels by Or G. O. Joy and Or A. M. Sage (21 pp, 77 references).

By L Dyer, G. J. Wilkie, P. Walters, B Tadesse, L. Keeney

Grade Engineering® is a term trademarked by the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) and includes five key levers for upgrading ores and rejecting waste prior to expensive downstream comminution and mineral processing. These five levers include natural deportment, induced deportment, bulk sorting, particle sorting and gravity separation. Over the past ten years, CRC ORE has progressed a range of technologies that exploit these levers from laboratory proof of concept through to large scale demonstration and validation. This paper details the work carried out by CRC ORE and Curtin University for assessing the amenability of an ore for its natural deportment and particle sorting attributes in an Integrated Screening and Particle Sorting (ISPS) Grade Engineering® process. ISPS is seen as a preferred method for Grade Engineering® as compared to individually operated unit operations as the benefits of each can be complementary. Furthermore, it is suggested that integrating the two levers has two important impacts: 1. Firstly, there is a risk that isolated particle sorting test results will be misinterpreted as being representative of the full sample without considering the mass balance impact of high-grade material that might have been lost in the fines fraction. This fine fraction will not be detected through the particle sorter. 2. Secondly, and potentially of more valuable impact, is that the opportunity may exist to upgrade the feed first through determining if there is a concentration of high grade to the fine (or coarse) fraction which can be separated through screening. Undertaking screening in the preparation stage of the particle sorting process will enable analysis and separation of the fine or coarse fractions of a rock mass. The result of this study provides the mining industry with an independent framework for undertaking an Order of Magnitude (ISPS) Grade Engineering® assessment on a range of constituent ore types. Keywords: Grade engineering, particle sorting, grade by size fractionation

Jan 1, 2020

"Coal seam gas problems can adversely affect the safety and productivity of underground coal mines, leading to fatalities and financial losses. Conventional gas management technologies using ventilation and gas drainage are unable to deal with the high and irregular gas emissions associated with high-production longwall mining. New technologies need to be developed to supplement the traditional gas management techniques to minimize the hazard of coal seam gas. Thin spray-on liners (TSLs) have gained some success for rock surface support since their introduction to the mining industry. Due to their relatively low permeability and appropriate mechanical properties, TSLs also show potential to be used as a gas management tool in underground coal mines.In this paper we review the current gas management challenges and discuss the potential use of TSLs as a gas management tool in underground coal mines. This may involve reducing gas migration into the excavations/roadways, enhancing in-seam gas drainage, and preventing spontaneous combustion. Some potential areas for future research work are identified. IntroductionWhen a coal seam is influenced by mining activities, gas stored inside is liberated into the underground ventilation system. Gas emissions have created serious difficulties for the coal mining industry around the world. Therefore, coal mines have to develop effective strategies to control the gas concentration below the threshold value to meet statutory requirements. Ventilation has been the first solution in gas management for underground coal mining. When the emitted gas cannot be effectively diluted by ventilated air, gas drainage using pre- and/or post-drainage has to be introduced. However, even with ventilation and gas drainage, irregular gas emissions usually increase the gas concentration in roadways and slow down the development rate, thus causing significant economic loss to the coal mining industry (Thakur, 2006). Therefore, new technologies need to be developed to address this issue and mitigate the explosion risk."

Jan 1, 2016

By S. C. Maji, U. S. Chattopadyay, S. Chaudhuri, T. Gouri Charan

India is devoid of coking coal resources, which is a vital raw material for coke making. As a result it has to import about 80% coking coal for steel making. Indian National Steel Policy, 2017 has envisaged crude steel production around 300 million tonnes Mt) by the year 2030-31 and forecasts coking coal demand of 161 Mtpa (million tonnes per annum). One way of improving the indigenous resources is to study the performance of existing washeries and to improve the clean coal recovery by adopting suitable technology. A study was carried out, mainly to focus on the fine coal circuit of an existing coking coal washery, to generate the desired quality of clean coal. The operating coking coal washery being studied is presently feeding coal from nine different sources with varying feed ash contents. The coal fines varied in ash content ranging from 19.5% - 43.6%. For treating the coal fines, the washery has operated a spiral for the past few years. Performance studies were carried out, and it was found that the spiral is not efficient in recovering the cleans. Detailed investigations were carried out on the coal fines using flotation techniques, and it was found that to achieve a low ash clean coal, the froth flotation is a much better beneficiation option than a spiral, The studies showed that the recovery of clean coal through a spiral is 67.7% at ash content of 27.0%, while flotation tests showed a recovery of 68.1% at 16.5% ash content. Keywords: Coking coal washery, near gravity material, spiral washer, froth flotation

Jan 1, 2020

By I. O. Flores, A. Anani, H. Li

Current technological advancement has increased the exploitation of deeper ore bodies using underground methods. In certain cases, the mineral deposit starts near the surface and continues deep within the earth's crust. Such deposits are best mined with both underground and surface methods. Two main techniques are used to determine the optimal transition depth from surface to underground - a disintegrated approach and an integrated approach. Both methods have limitations in their use to determine the optimal transition depth. The objective of this research is to investigate the conditions in which an integrated approach to the transition depth problem is superior to a disintegrated approach. Three binary integer linear programming models are developed for this purpose: a surface and underground model for the disintegrated instance and an integrated model. A case study is performed to validate the models, with a comparative sensitivity analysis to obtain operational insights.

Sep 1, 2021

By M. B. Shongwe

Pt-based alloys are being developed for high-temperature applications with the aim of replacing some of the currently used Ni-based superalloys (NBSAs) in the highest temperature applications. The Pt-based alloys have a similar structure to the NBSAs, and since Pt is more chemically inert than nickel and has a higher melting point, they can potentially be used at higher temperatures, up to 1300°C, and in more aggressive environments. Several experimental Pt-based alloys were studied at Mintek, and an optimum composition was found to be Pt84:Ahi:Ru2:Cr3 (at.%). On the basis of hardness and microstructure, a later study identified a new optimum: Ptr8:A111:Ru5:Cr6 (at.%). There are at least two Pt3A1 allotropes, and the high-temperature cubic structure has better properties than the lower temperature tetragonal form, and so needs to be stabilized. This work describes the latest results obtained in transmission electron microscopy (TEM) studies of the quaternary Pt-based superalloys. These results are both interesting and important, because the samples have a higher precipitate density compared to those from earlier work. The precipitate morphology is mainly cubic, with minor areas having irregular-shaped precipitates. The high volume fraction of the precipitates is a major breakthrough, since the objective of this work is to improve the alloys. A prior disadvantage was that the proportion of the precipitates was too low in samples before this work, especially compared with the work from Germany on Pt-Al-Cr-Ni¬based alloys as well as the NBSAs. TEM -Pt3A1 diffraction patterns were studied, and for each diffraction pattern, many possible lattice point combinations were tried, with the angle between the lattice spots as well as interplanar spacings being calculated for each phase (cubic or tetragonal) to match the measured results. An overall analysis of the diffraction results indicates that the cubic phase fitted the experimental lattice points with much lower errors compared to the tetragonal phase. Thus, with the close match achieved with the cubic structure, the structure of -Pt3A1 precipitates is likely to be cubic. X-ray diffraction has been carried out on selected samples, and the results confirmed the presence of cubic -Pt3A1 and (Pt). Different X-ray diffractometers were used to further verify the results, and the results were also compared with those from TEM.

Jan 1, 2012

By C. B. Carelse, M. Manuel, D. Chetty

Automated mineralogical analysis of platinum group minerals (PGM), using the mineral liberation analyser, provides information used to understand flotation efficiency, primarily from a PGM liberation and association standpoint. To date, however, there is no consistent understanding regarding PGM speciation and its impact on floatability. Previous studies of PGM from UG2 ores concluded that a larger dataset is needed from which the various parameters can be modelled. Parameters on telluride, arsenide, sulfurarsenide and alloy species need to be integrated to fully understand the impact of PGM speciation on flotation, and for this, ores other than PGE-sulfide-rich UG2 must be assessed. Flotation rougher rate tests were performed on feed samples from two Platreef ores to determine the flotation response of individual liberated PGM species. This was achieved through automated mineralogical analysis of feed, rougher concentrates and tails. Based on 1529 liberated PGM grains assessed over the circuit for two Platreef ores, preliminary results show that PGM speciation, species grain size and competition from gangue appear to influence floatability in an ‘optimised’ laboratory environment. Keywords: PGM, PGM species, flotation, liberation

Jan 1, 2020

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

The addition of binder to full plant tailings significantly affects the rheology of a backfill mixture and, consequently, the pressure gradients in the pipeline. The binder increases the yield stress and apparent viscosity of the mixture, and the transition velocity between the laminar and turbulent flow regimes. In a test conducted at a slurry relative density of 1,72 with binder addition, the mixture also exhibited time-dependent behaviour owing to the hydration of the binder.

Jan 1, 1993