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By J. P. Gouvea

Back-analysis of two mining-induced tremors in 2011 was used to determine a modelling criterion for the entire Klerksdorp Goldfield (i.e., Vaal Reefs region). At that time, most mining operations in the region were owned by AngloGold Ashanti (AGA) and shared many geotechnical similarities. By 2018 AGA had sold off all its Klerksdorp operations to different mining companies, which continued applying the 2011 modelling criterion. As mining activities became more remote, scattered, and isolated, the extraction of isolated blocks of ground and remnants became increasingly necessary. However, the inherited criterion allowed only minimal or no mining activities at these areas. Keeping in mind that safety is the overriding consideration, an innovative numerical modelling approach, which includes the application of peak particle velocity designs, was developed to provide practitioners in the Klerksdorp Goldfield with a suitable criterion to justifiably and safely mine isolated blocks of ground and remnants. This would not always be possible if a conformist approach was used.

Mar 14, 2024

By N. Naude, L. S. Leal Filho, M. P. Tshazi

In this paper, the authors performed experiments in the Denver and Leeds laboratory flotation devices at the University of Pretoria at various particle sizes to evaluate the performance of the devices. Quartz was used in a single mineral system at discrete sizes fractions, -25 μm, +25- 45 μm, +45-75 μm, and +75-106 μm. Hydrodynamic analysis, based on dimensionless power and Reynolds numbers, indicated that the Leeds cell required higher power input to achieve comparable flow conditions. Specifically, the Leeds cell exhibited an average power number of 1.03, whereas the Denver cell averaged 0.77 within the same impeller speed range of 1000 rpm–1500 rpm. For comparative flotation performance, impeller speeds were calibrated, resulting in operating speeds of 1200 rpm for the Denver cell and 1400 rpm for the Leeds cell. The cells performed similarly at two coarser-sized fractions. However, some deviations were observed in the finer particle size range. The -25 μm (fine) fraction initially achieved a recovery of only 15%. An additional reagent dosage was required to enhance the recovery of this fraction significantly. These findings highlighted the influence of particle size on flotation recovery. For all experiments, the Denver laboratory flotation cell outperformed (defined by higher recovery) the Leeds device, while still operating at a lower impeller speed. This advantage can be attributed to its impeller-stator design and air dispersion features, effectively overcoming slurry resistance and resulting in superior flotation performance compared to the Leeds cell.

May 27, 2025

By B. Mbuya, A. F. Mulaba-Bafubianda, J. M. Mvita

The paper explains the main effects of input leaching parameters, such as addition of a reducing agent, acidity, agitation, temperature, and leaching system potential, in relation to observed and predicted yields of sought-after cobalt. An artificial neural network coupled with graphical probability networks was developed wherein the abovementioned input parameters were used to predict the percentage of dissolved cobalt. Furthermore, similarities and differences between the Bayesian and neural network approaches in terms of their key outcomes are compared with respect to study of the dissolution of cobalt in sulfuric acid. Key results indicate that there is a need to use neural network results to predict conditions for dissolution of cobalt, while using Bayesian network to explain inferences about conditions of the input parameters, thereby achieving realistic predictions.

Jan 1, 2023

By J. A. Kinnaird, B. J. Youlton, K. L. Youlton

Methods for treating and processing refractory gold ores are well established. However, what is less well understood is how the formation of the gold-bearing deposits affects gold processing and extraction. In order to evaluate the effect of ore genesis on gold extraction a number of South African gold deposits were studied. These included complex Pilgrim’s Rest samples as well as refractory Fairview, Barbrook, and Consolidated Murchison samples. We found the refractory nature of gold ores is controlled by a limited number of well-understood mineralogical factors. Solid solution gold is linked to low temperature and pressure conditions in fine-grained sedimentary lithologies, while reactive pyrrhotite can form from hydrothermal fluids associated with mafic magmatic rocks. These formational controls can be used to identify and avoid complex deposits at a desktop study phase, or address and reduce complications further along the pipeline using early mineralogical studies.

Jun 1, 2021

At the Annual General Meeting of the Chamber of Mines of South Africa, held in Johannesburg on 29th June, 1982, the following leading members of the mining industry were elected to office for the 1982-1983 term: Mr W. W. Malan President Mr C. T. Fenton Vice-President Mr G. Y. Nisbet Vice President William Wouter Malan was born in Springs on 7th November, 1928, and was educated at the Springs High School and the University of the Witwatersrand, where he obtained a B.8c degree in mining engineering. Diamond Mines. Mr Nisbet became a consulting engineer of the Anglo American Corporation in 1972, and a deputy managing director of the Gold Division in 1974. George Young Kisbet was born in Benoni in 1923 and was educated at Pretoria Boys High and the University of the Witwatersrand. Mintek reports Report 2010D A process for the recovery of rare-earth oxides from monazite. (First published 16th March, 1979). Report 2073D A preliminary investigation of the concentration process at Ucar Minerals Corporation. (First published 19th September, 1980). Report 2092D The recovery of pyrite from gold ore by gravity separation. (First published 28th November, 1980). Report M13 Factors affecting the production of fines during the screening and handling of highcarbon ferromanganese.

Jan 1, 1982

Palladium Alloys. E. M. Savitskii, V. P. Polyakova, M. A. Tylkina. Translated by: R. E. Howard. Published by Primary Services, New York, N.Y. 10012. $24.50. The output of palladium in the U.S.S.R. greatly exceeds the internal usage. The primary purpose of this 200 page volume is therefore to record details of fundamental researches on the properties of this metal with a view to expanding its marketability. Theoretical studies have revealed a number of alloys with great promise in electrical instruments and for the chemical industry. The success of these researches in the U.S.S.R. and in the U.S.A., resulted in the industrial usage of palladium exceeding that of platinum in 1957 and increasing its lead during the next decade. This volume is divided into three parts. Section I covers the mineralogy, extraction and the physical metallurgy of the metal. It records a considerable area where the resistance to corrosion of palladium equals that of platinum. Section II deals with the preparation and the properties of palladium in alloys and contains a comprehensive metallographic treatment of the many binary alloy systems. Section III is devoted to industrial applications. The 460 references which are quoted are mainly from the U.S.S.R. but otherwise have a world-wide coverage. H.B.

By L. Linzer, J. Oelofse, T. Rangasamy

Extraction of isolated blocks of ground with elevated levels of stress and/or seismicity is a common occurrence in South African gold mines. Isolated blocks of ground that are divorced from the main orebody and are bound by complex, dip and strike parallel, non-persistent geological structures dominate the Klerksdorp gold fields. No quantifiable methods exist to assess the risk associated with mining these and other classes of remnants. A case history, from a gold mine that planned to extract three remnant blocks hosted in a large complex fault system, is used to illustrate the decision making process based on a combination of underground observations, numerical and seismic techniques. Simple risk estimation matrices were developed and used to estimate remnant-mining risk and finally to quantify the decision on which of the three remnant blocks could be extracted at the lowest possible geo-mechanical risk. Il est courant dans les mines aurifères sud-africaines d’extraire des blocs de terrain isolés qui possèdent des niveaux élevés de contraintes et/ou sismicité. Les régions aurifères de Klerksdorp sont dominées par des blocs de terrain isolés qui sont séparés du gisement principal et qui sont retenus par des structures géologiques non continues, à parallèle de pendage et direction, et complexes. Il n’existe pas de méthodes quantifiables pour évaluer le risque associé à l’extraction de ce genre et autres genres de résidus. Une observation de cas, celle d’une mine d’or qui avait l’intention d’extraire trois blocs de résidus qui se trouvaient dans un grand système complexe de faille, est utilisée pour illustrer le processus décisionnel basé sur une combinaison d’observations souterraines, et de techniques numériques et sismiques. Des matrices simples d’estimation de risque furent développées et utilisées pour estimer le risque lié à l’extraction des résidus et finalement pour quantifier la décision sur lequel des trois blocs de résidus pouvait être exploité au moindre risque géo-mécanique. Die Extraktion isolierter Gesteinsblöcke mit erhöhtem Spannugsniveau oder Seismizität ist in südafrikanischen Goldminen üblich. Isolierte Gesteinsblöcke, die von der Haupterzader getrennt und durch komplexe, parallele abfallende und horizontale nicht persistent geologische Strukturen gebunden sind, beherrschen das Klerksdorp Goldfeld. Es gibt keine quantifizierbare Methoden die das Risiko welches mit dem Abbau dieser und anderer Klassen verbunden ist beschreiben. Eine Fallstudie einer Goldmine, welche die Extraktion von drei in einem großem komplexen Verwerfungssystem eingelagerten Einschlußblöcken plante, wird verwendet um den Entscheidungsprozeß zu illustrieren, der auf einer Kombination von Untertag Beobachtungen und numerischen und seismischen Techniken basiert. Einfache Gefahreinschätzungsmatrizen wurden entwickelt und angewendet um das Abbaurestrisiko abzuschätzen und letztendlich die Entscheidung zu quantifizieren, welcher der drei Einschlußblöcke unter dem niedrigst möglichen geo-mechanischen Risiko extrahiert werden konnte .

Jan 1, 2003

By P. G. Kovalchik

Overexposure to noise remains a widespread, serious health hazard in the US mining and other industries despite 25 years of regulation. Most categories of illnesses and injuries associated with mining have improved, with the exception of hearing loss. The drilling of rock in a confined work environment contributes to high levels of noise exposure in mining. The National Institute for Occupational Safety and Health (NIOSH) is conducting research to reduce the noise exposures of jackleg drill operators and to prevent additional cases of noise induced hearing loss (NIHL) by developing and evaluating low-cost retrofit noise controls for equipment. This report describes the procedure for the measurement and reporting of noise from portable pneumatic tools such as jackleg drills. The technique used in this research allows for the determination of the source A-weighted sound power levels and the radiation patterns in octave and 1/3 octave bands. Overall sound power level is also determined. This paper also reports the results obtained by using this procedure to evaluate a SECO S215 standard production drill and a CSIR Miningtek prototype rock drill incorporating engineering noise control measures. It was found that by using the manufacture?s recommended operating pressure of 496 kPa (72 psi) that the CSIR prototype?s sound power was 10 dB(A) less then that of the SECO S215.

Jan 1, 2009

By L. A. Balzan, M. Kalicinski, F. Nieuwenhuys

GEOSCANs on belt analysers have been widely utilised in iron ore for nearly two decades. Since the first installations in 2003, the availability of accurate and reliable grade data has become standardised across iron ore mines in the Northern Cape, where various streams are monitored continuously to ensure the optimal functioning of plants. Assmang Khumani has been at the forefront of technology adoption and has implemented 19 GEOSCANs at various locations throughout the plant, monitoring run-of-mine, stockyard feed, beneficiation plant feeds, and products. Over the years, collaborative advances in the technology have allowed for numerous benefits and gains to be made. In recent times, there has been a concerted effort on the development of analysis for phosphorus in the material flows, and based on Scantech's experience in the phosphate industry, this element has now been calibrated to achieve statistically acceptable and repeatable accuracies for real time analysis of this element on many of Khumani's GEOSCAN analysers. This paper provides an overview of GEOSCAN use at Khumani, while focusing on the development of phosphorus analysis. A case study of analysis results is presented for a range of analysers that have been calibrated for this element, as well as a discussion on the benefits obtained as a result of this analysis. Keywords: Online analysis, real-time, process control

Jan 1, 2020

By G. H. Morton

The tenth international symposium on the application of computer methods in the mineral industry (APCOM) was held in Johannesburg in April; the first time it had taken place outside North America. In the technical sessions fifty-seven papers were presented, providing a review of current work and including some important original contributions. These papers and a full account of the discussion at the symposium will soon be published in a single volume. The Technical Programme The first session of the symposium included an opening address given by Mr J. W. Shilling, President of the Chamber of Mines of South Africa, and a keynote address by Mr K. F. Lane of the Rio Tinto Corporation Limited. Mr Shilling spoke about the history of the South African mining industry and about some of the work of the Chamber of Mines. He stressed the importance of the symposium in familiarising those in mining with computer applications, and expressed his hope that it would stimulate and inspire scientists and engineers in the effort to develop safer and more economic methods of mining. Mr Lane, talking about economic and financial modelling, gave a fascinating account of the experience of RTZ over the last twelve years. In a very honest appraisal of the substantial progress that had been made, he confessed some disappointment not only in the cost and

By L. R. Nelson

The efficiency and cost-effectiveness of the aluminothermic reduction process in the production of ferro-alloys and 'pure' metals depends strongly on appropriate balancing of the process energy required. Insufficient energy results in a poor metal yield, while over-supply can result in excessive fuming and possibly even ejection of the reactor contents in a potentially dangerous 'thermite bomb' reaction. This situation becomes even more critical when the suitability of limited quantities of oxide from new sources must be evaluated, dictating smaller-scale testwork. The resulting higher relative heat losses from the system complicates control of the energy balance, and usually requires the addition of thermal boosters or reactant preheating in order to sustain an autothermic process. This often detracts from the quality of the metal product, and adds to the hazards of batch aluminothermic- reduction testing. The development of a small-scale method (producing less than 2,5 kg of metal) for the plasma-assisted aluminothermic reduction of chromium oxide that overcomes such difficulties is described. The technique involves the use of a sealed 50 kVA plasma-arc furnace to provide controlled electrical ignition and supplementary energy to the reactants contained in a water-cooled copper crucible. The application of the method to the evaluation of the aluminothermic production of pure chromium metal from a unique chromic oxide source is reported.

Jan 1, 1996

By M. Åstrand, M. Johansson

"Advanced planning and automation are increasingly important in modern mines. Sophisticated methods for long-term mine planning are often used, and the advent of autonomous machines makes the actual operation more predictable. However, the interface between these two timescales, i.e. the scheduling of the mobile production fleet, often limits the ability to operate mines at maximum profitability. We show how scheduling the production fleet in an underground mine can be modelled as a flow shop. A flow shop is a general abstract process formulation that captures the key properties of a scheduling problem without going into specific details. Thus, the flow shop enables mine scheduling to reap the benefits of scheduling research from other industries. We review recent results from the mining community and the flow shop community, and introduce scheduling methods used in these two fields. This work aims at providing value to researchers from the mining community who want to leverage their skill set, as well as to theoretical researchers by presenting the mining process as a potential application area. Lastly, we discuss the results, and outline some future challenges and opportunities facing the industry. IntroductionThe margins in underground mining are constantly under pressure since costs increase as the mine becomes deeper. One major component influencing the operational performance, and thus the profitability of an underground mine, is how the mobile machinery and staff are coordinated. Today, the coordination of the underground fleet, i.e. scheduling of the machines, is mostly done manually, with methods that are stretched to their limit and with no guarantees on performance. According to a survey of more than 200 high-level executives in mining companies around the world (Mincom, 2011), the top challenge for modern mines is to maximize production effectiveness, rather than improving the reliability of individual items of equipment. This highlights the importance of coordination on a system level.The effectiveness of mine production can be increased by introducing supportive algorithms in the scheduling process. These algorithms enable mines to construct optimized schedules with respect to custom metrics. Additionally, manual scheduling is a tedious and error-prone task where the performance is heavily dependent on the scheduler. To reduce the staff dependency, supportive algorithms can help to achieve more uniform outcomes, resulting in a more predictable process. In turn, this increases the transparency of the mining process through the entire production chain. It is worth noting that automatic scheduling has proved beneficial in many other industries, such as chemicals and metals (Floudas and Lin, 2004; Tang et al., 2001)."

Dec 1, 2018

In China, thin coal seams are rich in resources but are technically challenging. The mineable reserves in these seams account for 20.4% of the total coal resources, while the current production accounts for only 10.4% of the total annual production. Characteristics such as narrow mining space, low level of mechanization, poor working environment, and high cost of mining, restrict the development of mining safety and efficiency. Recently, fully mechanized mining technology has developed rapidly for thin coal seams, the level of yield and efficiency has reached or exceeded the international standard, and some state-owned key coal mines are considering automation of their mining process. In thin coal seams with hard stone bands that contain concentrations of pyrite, a specialized software, LS-DYNA, is used to calculate the rational blasting parameters that are used in the deep-hole pre-splitting blasting. Using this method the hard stone bands are fractured effectively, and hence increasing the coal productivity. In addition, mining advance rate were increased by enhancing the level of fully mechanized equipment and safety improved by increasing gas drainage from the gas outburst prone seam located some 7 m below the coal horizon. At present, thin coal seam mining technology faces many challenges, including the low level of equipment automation, the low advance rate in mixed coal-rock ground, and the large number of the mine personnel underground. By lowering the labour intensity and improving efficiency through automation and other measures, more efficient working faces can be implemented in thin coal seams.

Jan 1, 2012

By M. Asghari, R. Amiri, A. Haratian, M. Noue Parast, S. Haji

Today the roller screen has a wide range of applications in the steel-making industry. It is used for screening of green pellets before using the kiln. Since the appropriate size of a green pellet is -16+9 mm, there are different gaps between rollers that make green pellets classified in three categories: -9 mm (undersize), -16+9 mm (onsize) and +16mm (oversize). The efficiency of a roller screen is specified according to the weight percent of undersize in onsize as a fine material, and weight percent of onsize in oversize (loss). This efficiency is influenced by different operational parameters such as roller diameter, roller speed, and roller gap, material type of rollers and inclination of roller screen. This study investigates the effect of different material types of rollers in efficiency of Ardakan roller screens, located in the Yazd province of Iran. The rollers of the existing roller screens in this pelletising plant are made of polyurethane which according to this investigation, has a maximum lifetime of about six months. Operating the polyurethane rollers beyond its lifetime generates serious problems such as high wear of rollers, and consequently, material buildup on the roller surface which then significantly decreases the roller screen efficiency. So, after examining different roller materials, stainless steel 304 with higher surface roughness to help pellets move properly on the roller screen surface was selected as a solution to this problem. The new roller screen was constructed by Fakoor Meghnatis Spadana (FMS) and replaced the previous one. In this way, the maximum capacity of the roller screen was increased about 17% and the roller screen efficiency was increased about 15%. Keywords: Roller screen, green pellets, efficiency, onsize, operational parameters

Jan 1, 2020

By N. Mutemeri, T. -L. Field, M. Chuma

The categorization of artisanal and small-scale mining has a significant impact on perception and understanding of the sector, particularly from a livelihood perspective. Several developing countries classify different types of artisanal and small-scale mining based on legal status. Given the nature such activities, the tragedy of the commons theory has been applied to understand the inevitable environmental, economic, sociocultural, safety, and health negative externalities – which are products of informality and illegality. Consequently, formalization is a panacea to sustainability. This article aims to offer a conceptual organization and foundational knowledge for characterization of artisanal and small-scale mining. It seeks to identify existing literature on the subject to avoid replication and acknowledge other scholars. Moreover, the article aims to place the study within the context of existing literature, establishing relationships with other studies and why the research is necessary. This paper pinpoints gaps left from other studies in so far as the characterization of artisanal and small-scale mining is concerned. Thus, reviewing literature abetted in finding similarities and differences on how artisanal and small-scale mining is defined from a scholarly and legal basis. The paper ascertains major claims made by earlier research on this topic, such as environmental impacts, the lack of adequate regulatory framework, and presents querying and probing questions lacking from other studies.

Jul 10, 2024

By E. Lutz, M. Momayez, K. W. Brown Requist

As real-time air quality monitoring becomes more prevalent in US underground mines, it is important to provide the highest data reliability with the fewest possible sensors. Real-time sensors remain costly, and these costs are not exclusively financial; the time required to install, calibrate, and maintain real-time sensors poses a large barrier to widespread implementation. Current atmospheric monitoring systems typically rely on displaying point-specific values. This requires operators to infer real-time airborne contamination distributions. Monitoring and control software utilizing mine ventilation network (MVN) solvers has been implemented in limited cases because of their ability to simulate ventilation systems quickly, but these solvers use a one-dimensional representation of the mine, limiting spatial resolution of estimated distributions. Computational fluid dynamics (CFD) has likewise been considered as a means to improve spatial resolution, but processing times prevent its use as a basis for monitoring and control. For the real-time monitoring of airborne contamination distributions, we propose a spatial interpolation method that can estimate the distribution of airborne contaminants in near-real time. This method provides a middle ground between fast processing times and increased spatial resolution. With the use of a pathfinding algorithm and optimization through absolute percentage error minimization, this method outperforms spatial interpolation with a Euclidean distance. By providing contamination distribution information to operators, this method and its derivatives stand to outperform current atmospheric monitoring systems.

Apr 16, 2024

By Dick Minnitt

Large-scale variability in process plants and process control can be identified and controlled through disaggregating the overall variability in a process stream. Conventional statistics and Statistical Process Control (SPC) fail to address the concept of stream heterogeneity, therefore fail to identify and distinguish between the various sources of variability in a process stream. A modified set of 445 data from a process plant is used as an example to explain the benefits of variography in process control. Large-scale variability, usually in the form of product composition cycles and chemical cyclic variations may be manifest throughout a sampling system or a process plant, but this type of variability is most easily discernable in one-dimensional process streams. The Moving Average is a powerful tool for identifying large and small scale variability and cyclical behaviour in process streams, while the variogram is a custom built tool that allows the components of variability to be identified and resolved. The positions in the variogram at which the different variance can be read and the nomenclature of these types of variability is described. The transfer of variances converted to standard deviations to the Control Charts, allows an operator to appreciate the appropriateness of Upper and Lower control and specification limits. The overall contribution of the various sources of variability is represented in a pie diagram.

Jan 1, 2007

By Paul B. Crawford, Gerald N. Pitts

"A new method is introduced for the simulation by computer of the flow of liquid underground. The method has application in simulating, for example, liquid withdrawal systems, injection systems or injection-well systems. The computer simulation of liquid flow permits the utilization of the known properties of the rock in developing a model of the permeable rock mass.The flow properties of the rock at a specific site arc generated statistically using a random number generator. After defining in this manner the rock properties of each element in the computer grid, the streamlines or flow paths of the liquid are traced using the new method. The simulation is designed especially for computers. The meandering character of the liquids paths is displayed clearly as the fluid moves underground, thus providing the technical information required for the control of the movement of liquid."

Jan 1, 2014

By E. S. van Druten, M. C. Bekker

"The complete and successful closure of a mine in the South African environment remains problematic. Closure remains an elusive mining phase due to unclear roles and responsibilities, inaccurate closure management data, and the inability of stakeholders to conceptualize and integrate closure information into business processes. Currently there are no proven methods available to address the complexities encountered during a closure application, and to date no mine has been granted full closure. Many mines are left abandoned and unrehabilitated, resulting in risk to investors, surrounding communities, and regulators. This investigation aimed to determine, categorize, and rank reasons for unsuccessful mine closures. Focus groups consisting of public and private stakeholders were identified and surveyed through a structured, rank-order questionnaire to determine the relative importance of reasons why achieving formal and final mine closure remains elusive. Various requirements and aspects were identified and listed according to four categories: namely, primary, secondary, process drivers, and information sources. These aspects should be considered in the development of an integrated mine closure model.Background and rationalePrior to 1956, mine closures were not subject to legislative requirements, being merely governed by insufficient environmental regulations under the Mines and Works Act 27 (MWA) (Swart, 2003). In 1981 the Chamber of Mines (COM) published a document titled ‘The rehabilitation of land disturbed by surface coal mining’, which constituted the first notable contribution to environmental protection. This guideline was later referenced in the Minerals Act of 1991, which for the first time laid definite environmental burdens on the Mining Right Holder (MRH). The Minerals Act of 1991 was superseded by the current Mineral and Petroleum Resources Development Act (MPRDA) and the Mineral and Petroleum Resources Development Act Regulations (MPRDAR), which specify a regulatory process for mine closure applications and financial provisions."

Jan 1, 2017

By K. Koruyan

Although remote sensing technology has been available for many years, it has rarely been used for monitoring mining activity. Recent studies indicate that remote sensing is also a valuable tool for managing and planning certain aspects of the mining operation. In this paper, we examine areal expansion of marble quarries and the affected vegetation over a period of 10 years in the Mugla region in Turkey, using geographic information system (GIS) and remote sensing (RS) techniques. Images captured by ASTER Level 3A01 (3D Ortho Data Set), Landsat 5, and Landsat 7 satellites between 2001 and 2009 were used for the analysis. Changes in the natural vegetation as a function of the production level in the marble quarry were calculated using the normalized difference vegetation index. According to the study results, land cover and natural vegetation decreased by less than 3 per cent and 1 per cent respectively between 2001 and 2009, following an upsurge in mining activity in the region.

Jan 1, 2012