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By G. Asbjörnsson, E. Hulthén, P. Papadopoulou, C. M. Evertsson

Crushing plant managers need to assess, manage, and communicate the environmental impact induced by their crushing plant operations as a step towards the sustainable development of the company. However, performing reliable environmental impact calculations of crushing plants can be challenging when the availability of operational and emission data is low, and when the company’s environmental expertise is not adapted and connected to plant operations (or does not currently exist). To address these challenges, this paper proposes a practical approach where the lifecycle assessment methodology (LCA) is combined with process simulations in a web-based tool. To describe what functionality such a tool should have to be incorporated into a company’s workflow, the system that surrounds a crushing plant is analysed. Further, a case study with a three-stage crushing plant is introduced to showcase how the simulated power draw results produced with the beta version of the tool can be compared to measured sensor data from the crushing plant for one operational day. The results indicate that the simulation tool can provide an adequate estimation of the specific energy for the different material fractions and give an overview of the environmental impact of the process caused by electricity and explosives consumption. Plant managers and operators can use this tool to calculate the environmental impacts of their plant and simulate how different operational strategies influence them. Keywords: LCA, environmental impact, coarse comminution, crushing plant

Jan 1, 2020

By A. F. van der Merwe, R-D. Taylor, M. Jacobs, F. H. Conradie

Total bound moisture (TBM) is a typical quality indicator of industrial-grade gypsum. This gypsum is comprised of three distinct phases, namely anhydrite, dihydrate, and hemihydrate, of which only the latter is of much industrial use. TBM analysis is a lengthy laboratory procedure, and an artificial neural network (ANN) TBM inference measurement is proposed as a fast and online alternative. An ANN inference model for gypsum TBM based on plant data was developed. The inputs to the network were primarily focused on the plant's calciner, and different network topologies, data divisions, and transfer functions were investigated. Furthermore, the applicability of the TBM value as a quality indicator was investigated based on a gypsum phase analysis. A strong correlation between TBM and the gypsum hemihydrate and anhydrite content was found, validating the plant target TBM of 5.8% as a quality indicator. A network topology consisting of one hidden layer with logarithmic-sigmoid (logsig) and pure linear (purelin) transfer functions showed the best performance (R > 90%).

Oct 3, 2023

By J. van Deventer

Ion exchange is widely used in hydrometallurgical operations for the recovery and purification of valuable metals. Special chelating resins have a high affinity for specific elements, allowing the selective removal of low levels of impurities from a background of highly concentrated valuable metal. Solvent-impregnated resins have been added to this group more recently, expanding the treatment options. These products find application in the purification of cobalt-rich liquor prior to the production of high-purity metal or metal salts. Impurities in copper-cobalt circuits that are typically targeted by ion exchange include iron, uranium, copper, zinc, nickel, bismuth, and antimony. Ion-exchange resins can also be used to treat tailings, thereby recovering additional valuable metal and improving the Environmental and Social Governance credentials of the operation. This article takes a look at various applications of ion exchange in copper-cobalt operations

Jan 1, 2023

By J. H. van Dalen, P. J. Brandt, F. W. Wessels

A maximum of ten process streams (Merrill barren solutions) can be monitored sequentially with this on-line analyser, and gold concentrations as Iow as 0,005 mg/I can be determined. The design is a further development of the Tell-tale analyser constructed by the Corner House Laboratories during the period 1965-69. The barren solution is preconcentrated automatically by solvent extraction, the solvent being a solution of I per cent Aliquat 336 in di-isobutyl ketone. An aqueous-to-solvent ratio of 40: I is maintained. The extracted gold in the organic phase is determined by flame atomic absorption, each analysis taking approximately II minutes. The long-term reproducibility of the absorbance readings over a 24-hour period of repetitive sampling of four simulated process streams varied from 6,9 to 4,1 per cent relative standard deviation for gold concentrations of 0,0 I to 0,05 mg/I.

Jan 1, 1980

By C. Snyman, M. Le Roux, Q. P. Campbell, S. Engelbrecht

Due to the ultrafine particle size required for effective processing of chromite ores, dewatering of the concentrates presents a challenge. It is not uncommon for the ore to have elevated moisture contents even after dewatering, which must be reduced to required levels of between 8% and 10% by mass for further processing. Contact sorption drying has shown promise in test work on fine coal. This method was used to study the dewatering of chromite on a laboratory scale using 3 mm spherical activated alumina ceramic beads as a sorbent. Three different sorbent-to-chromite mass ratios, namely 0.5:1, 1:1, and 2:1, were tested with different process conditions, including dewatering in a stationary and a rotatingl bed. The experimental work showed that it was possible to achieve the target moistures in less than 10 minutes, irrespective of the sorbent-to-chromite ratio used. Ratios of 1:1 or higher, however, proved to be the best. The sorbent reusability at mass ratios of 1:1 and 2:1 were therefore tested. With a 1:1 mass ratio, the sorbents could be reused for three cycles, while with 2:1 ratio, the number of cycles increased to six. The sorbent-to-chromite mass ratio used had a significant influence on the required contact time and the reusability of the sorbents.

Oct 3, 2023

By F. T. Cawood

This article offers a personal and independent view on the threats to the sustainability of the South African minerals industry. It argues that if the six identified threats of insufficient spending on research and development, general standard of education, nationalization, inadequate infrastructure, Aids prevalence and labour inefficiency are not acted upon as a matter of urgency, the future of the mining industry, along with its important contribution to the economy, is at risk.

Jan 1, 2011

By K. -C. Han, S. -Y. Kim

This study was carried out in a bid to survey Ganboke gold mine in Pala, Mayo-Kebbi Province, southwestern Chad. The Ganboke mine is now being prepared for investigation and development, and the research sought to perform rock properties tests of relevant rocks through its geological survey, rock mass evaluation, and in-situ and laboratory tests and analyze the stability by the means of limit equilibrium method, thereby suggest appropriate methods to design the pit slope and individual benches in Ganboke mine. Targenting GS1-GS1' section with the depth of 180 m and GS2-GS2' section with the depth of 150 m in the survey area, we set the height of the bench at 10 m and 15 m, and the angle of bench at 60o and 70o, respectively, and then reviewed the stability for dried condition and saturated condition. The result of examination indicated that it would be appropriate to set the bench height at 10m and the bench angle at 60o in developing the mine slopes concerned. Cette étude est réalisé dans le but de faire des recherches sur Ganboke mine d'or dans Pala, Mayo-Kebbi Provence, Tchad sud-ouest. La Ganboke mine est actuellement en train de étre disposé à la investigation et le développement, et la recherche a cherché à accomplir les tests de la propriétè des roches par l'intermédiaire de la étude géologique, la évaluation de la masse rocheuse, et in-situ et les tests de laboratoire et à faire l'analyse de la stabilité au moyen de la méthode d'équilibre limite, de ce fait à proposer le methodes propres à faire le plan de la pente et les gradins individuels dans la Ganboke mine. Concernant la section de GS1-GS1' avec la profondeur de 180 m et la section de GS2-GS2' avec la profondeur de 150 m dans l'aire d'étude, nous mîmes l'hauteur du gradin à 10 m et 15 m, et l'angle du gradin à 60o and 70o, respectivement, et alors nous avon reconsidéré la stabilité pour la condition sèche et la condition saturé. Le résultat d'examen a indiqué que il pourrait être propre de mettre l'hauteur du gradin à 10m et l'angle du gradin à 60o en développant les pentes de la mine concerné. Diese Forschung wurde um das Gold Bergwerk zu überschauen in Pala, Mayo-Kebbi Provinz, der Südwesten Chad ausgeführen. Das Ganboke Bergwerk ist jetzt zur Erforschung und Entwicklung vorgebereiten worden, und die Forschung suchte zu ausführen die Prüfungen der Felseigenschaft durch geologischen Überblick, Felsmassewertbestimmung, und In-situ und Lavorversuch auf, und analysieren die Stabilität mittelst der Grenzegleichgewichtsmethode, da-durch schlug die angemes-sen Methoden zu entwerfen die Böschungen und die einzelnen Bänke im Ganboke Bergwerk vor. Für den Abschnitt GS1-GS1' mit der Tiefe von 180 m und GS2-GS2' mit der Tiefe von 150 m in der Überblickfläche, wir setzten die Bankhöhe an 10 m und 15 m, und das Bankwinkel an 60o und 70o, beziehungsweise, und dann zurückblickten die Stabilität für die getrockneten Bedingungen und die gesättigten Bedingungen. Das Ergebnis der Untersuchung anzeigte daß es würde angemessen sein zu setzen die Bqnkhöhe an 10m und das Bankwinkel an 60o in der Entwickelungen vom Bergwerk be-teiligt.

Jan 1, 2003

By Y. Zhen, N. Topliffe, G. Shou

The typical service life for a long distance slurry pipeline is15 to 25 years. Determination of wear rate for a pipeline could have a high economic impact on the pipeline project. Wear is a combination of chemical corrosion and mechanical abrasion. The contribution of each factor has to be determined project by project. Normally, chemical corrosion dominates the pipe wear in fine slurry pipelines. These pipelines have been designed with a velocity between 1.5 m/s and 2.5 m/s. Solids are suspended with high homogeneity across the pipeline section. Bottom wear is not much greater than the top wear and not sensitive to velocity. The wear pattern in the pipeline transporting medium coarse solids, such as milled ore and tailings, is different. Wear concentrates on the bottom of pipeline and the outer bends, and is more sensitive to flow velocity. Wear distribution along the pipelines is similar.

Jan 1, 2007

By G. R. Drennan, N. J. Wagner, M. J. T. Sebola

The Soutpansberg Coalfield hosts South Africa's hard coking coal reserves. However, coals in this region are understudied compared to other coalfields in the country. This study characterizes the properties of fine-float fraction samples extracted from a wide diameter borehole core in the Makhado Project, Tshipise sub-basin, Soutpansberg coalfield. Conventional analyses were used to determine the coal quality, petrographic composition, mineralogy, geochemistry (including trace element and rare earth element composition), and free swelling index of samples from six coal horizons and three partings from the economic No.6 Seam. The coal samples are classified as medium rank bituminous C coals (0.88 %RoVmr, 0.92 %Rmax) and are highly vitrinitic in composition (97 vol% mineral matter free (mmf)). The samples show strong caking potential (FSI of 9). The total rare earth concentrations range between 570 and 3193 ppm in the ash samples. Preliminary analysis show all but two samples are promising sources of rare earth elements as the total concentrations exceeded the 1000 ppm cut-off grade. Further research is required to confirm these preliminary findings.

Aug 2, 2022

By H. E. Parkinson, Y. P. Chugh

About 90 percent of the coal mined underground in the U.S.A. today is mined by the room-and-pillar system. The productivity of the system dropped from about 14,1t per man-day in 1969 to about 7,3 t per man-day in 1978. Since 1974, the U.S. Department of Energy (formerly the U.S. Bureau of Mines) has been engaged in research to improve the production and productivity of the room-and-pillar system. The effort involves the development of integrated, automated, and remote-controlled equipment and systems including remote-controlled continuous miners, automated miner-bolters, automated extraction systems, continuous haulage systems for use behind miners, and remote-controlled equipment for miners, bolters, and shuttle cars. These systems are discussed briefly, the discussion being related primarily to coal winning, although the concepts could be utilized in room-and-pillar systems in mines other than coal mines.

Jan 1, 1981

The October General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 21st October, 1970, at 4.30 p.m. V. C. Robinson (President) was in the chair. There were also present 25 Fellows, including J. K. E. Douglas, Prof D. D. Howat, D. G. Maxwell, Dr R. E. Robinson, P. A. von Wielligh (Council Members). D. Ayres, G. Burrow, E. H. D. Carman, D. L. Carson, M. E. E. Douglas, S. A. Finney, W. R. Flook, A. J. Freemantle, W. A. Gilbert, E. B. Gordon, B. W. Gray, J. M. Jacobs, P. H. Kitto, C. H. Kruger, Dr P. J. D. Lloyd, D. G. Malan, W. Pilkington, W. G. Pyne-Mercier, K. S. Rae, W. T. Ruhmer, D. J. Tutt and D. T. Watt. Seven Members, including E. J. Dominy, S. I. du Preez, L. V. Grobler, D. R. Lings, G. D. Louw, J. S. A. Oelofse and O. B. Prentis. Fifteen Visitors, including J. R. Coppin, Dr A. Faure, P. E. Franzl, G. P. Hart, D. van Heerden, A. W. Hunt, A. R. F. MacDonald, B. G. Meyburgh, P. H. Radcliffe, J. M. Shirley, T. H. Tunley, A. D. Vellema and R. E. Wheeler. Secretary, D. C. Visser. Total present: 49. OBITUARIES The President: "It is my sad duty to announce the death of the following: Sir George Arthur Davenport, Honorary Life Fellow, who joined the Institute in 1930 and passed away on 17th September, 1970. The late Sir George was also, for many years, our corresponding member for Rhodesia. Andrew Malcolm Carmichael, Associate, who joined the Institute in 1944 and passed away on 22nd August, 1970. Cyril John Douglas Veal, Life Fellow, who joined the Institute in 1929 and passed away on 27th August, 1970. As a mark of respect to the memory of the deceased and in sympathy with the bereaved I would ask you all to rise and observe a few moments' silence." CONFIRMATION OF MINUTES The President: "May we confirm the minutes of the Annual General Meeting held on 26th August, 1970, and the minutes of the monthly general meetings which were held on the 20th of May and the 17th of June, 1970, as published in the August Journal." Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates, having been published in accordance with By-Law 5.2.2., Council has elected them to membership of the Institute in the following grades: Members: Nikolaos Lalakakis, Gordon Phillips Rundle. Associates: Henry du Preez, James Robert Forbes, Johannes Stephanus Albertus Oelofse, Casper Vorster van Heerden. Graduates: Michael Harold Crosbie, Graham Robert Wallis Walker, Gary Walker Braithwaite. Students: Mohammad Ali Kazemzadeh, Gerhardus Petrus Benade. APPLICATIONS FOR TRANSFER From Graduate to Member: James Wormald. From Student to Graduate: Peter John Cook, Pieter Willem Greeff. "I welcome the newly elected members to the Institute and congratulate the members who have been transferred to a higher grade." PAPER FOR PRESENTATION The President: "This paper is entitled 'The Design, Erection and Operation of a Purlex Plant at Buffelsfontein Gold Mining Company Limited'. It is presented to the Institute by Mr B. G. Meyburgh, a visitor to our Institute. He is a graduate of the University of the Orange Free State and is the Uranium Plant Superintendent at Buffelsfontein and he, therefore, is in a very strong position to describe this very excellent job which is being done as he has been associated with this plant from the inception." After the presentation of the paper the President said: "Gentlemen, the paper you've heard from Mr Meyburgh is a very concise and interesting account of an important piece of work, and I think the title is so completely descriptive of the subject, which is admirably set out in the paper which you have heard. You probably haven't all had the opportunity of reading it, but you very soon will. I found it interesting to note that the results predicted were surpassed in the operation of the plant to date. The actual results obtained are significantly good, I think. Any process which, in this country, increases production and decreases costs, is to be welcomed, particularly when it is so necessary for South Africa almost to bend over backwards to utilise every avenue available in order to increase the scope of the production for overseas' markets, of her metallurgical and mineral potential. In lighter vein-and there is no reason why we should always be so serious-I am glad to see that, in a scientific journal like this, such words as the American word 'crud' which I have been picked out about so often, because my grandchildren use it, is now given an aura of respectability. Thank you very much, Mr Meyburgh, for an interesting paper. We have a long list of contributors, and I am not going to waste any more time. I am going to call on Mr Tunley of the N.I.M. for the first contribution." T. H. Tunley, P. de Bruyn (read by A. D. Vellema), E. J. Dominy, E. H. D. Carman, A. R. F. MacDonald D. C. Streicher (read by P. H. Radcliff), Dr A. Faure and Dr P. J. D. Lloyd then contributed to the discussion. (This discussion will appear in a later issue of the Journal.) The President: "I wish to thank members and visitors for their attendance, and now declare the meeting closed." The meeting closed at 6.05 p.m.

By R. M. G. Machunter

The use of testwork to establish an economically feasible separating plant has been a long established practice in the mineral processing industry. However, uncertainties in orebody characteristics and equipment/plant operation can have a significant impact on the separation performance of a given project. This paper explores the impact of uncertainties derived during testwork at key processing stages on the overall performance of mineral processing flowsheets. Case studies for both mineral sand and iron ore projects will be used to illustrate the concepts studied in this paper.

Jan 1, 2007

By R. G. B. Pickering

The South African narrow reef hard rock mining industry has been stuck in a time warp with relatively little change in the mining process in the last century. This paper presents a methodology on how to implement change in narrow reef hard rock mining. It then explores a number of technologies that have been introduced into this mining industry and the impact that they have had on the mining process. The author then presents his view on whether the defined change process has been followed and sets out to identify the most critical aspect of ensuring that change is successfully implemented. Future demand will also be speculated on.

Jan 1, 2007

By G. R. Marchant, B. K. Loveday

"A mathematical model has been developed for flotation circuit simulation. This model was designed to investigate the effect of varying the circulating loads and to determine whether an improvement in overall efficiency could be gained by a size separation prior to flotation.Model parameters were obtained by regression to plant data. Highly correlated parameters in the model were combined to reduce the number of parameters so that the need for excessive data gathering was eliminated. Mass balance smoothing was used to obtain a consistent data set for regression.The results of the simulation indicate that for the same grade of concentrate, an increase in copper recovery of 0.6 per cent may be Possible by increasing the circulating loads. The results of the simulation also indicated that recleaning of the plus 200-mesh material may be beneficiaL."

Jan 1, 2014

By M. C. J. van der Merwe

"Carboxymethyl cellulose is an organic binder used in the iron ore pelletizing industry. The basic principles of how carboxymethyl cellulose (CMC) solutions behave during the pelletizing process and how these principles affect the drop and compression strengths of the pellets are poorly understood. The aim of the investigation was therefore to gain knowledge on the behaviour of CMC during the pelletizing of haematite concentrate.Haematite pellets with different additions of CMC (0.1–0.4 wt%), were subjected to drop tests, compression tests, and free moisture content analysis. The relationship between the drop strength, compression strength, free moisture content, elapsed time, and CMC concentration was analysed.The drop strength had a strong correlation with the free moisture content of the haematite pellets, with a correlation coefficient of 0.94. The compression strength of the CMC-bonded haematite pellets increased as the free moisture content decreased, reaching a maximum upon depletion of the free moisture content. Haematite pellets with CMC concentrations of 0.1 and 0.2 wt% developed most of their strength within the first day after pelletizing, whereas pellets with concentrations of 0.3 and 0.4 wt% developed most of their strength between one and two days after pelletizing. The time within which CMC-bonded haematite pellets develop most of their strength is therefore dependent on the CMC concentration. IntroductionFines are produced during the beneficiation of iron ore. These fines are separated from the lump ore and can be upgraded to produce a concentrate, which is used as a raw material for the production of pellets. Pellets in turn form a key burden material for direct reduction processes as well as the blast furnace (Zhu et al., 2015).Inorganic binders such as bentonite have been used predominantly in the iron ore pelletizing process to obtain pellets with suitable properties (Eisele and Kawatra, 2003). These binders, however, have the disadvantage of introducing impurities into the pellets. This has resulted in organic binders being pursued as suitable replacements for inorganic binders, of which carboxymethyl cellulose (CMC) shows good potential. Although CMC has been used as an organic binder in iron ore pelletizing, the fundamental principles of how it behaves during pelletizing and how these impact on pellet properties are poorly understood."

Jan 1, 2017

By M. Coetzee

The susceptibility of experimental low-nickel Cr-Mn-N stainless steels to hot cracking, sensitization, and pitting corrosion in the as-welded condition was investigated. These steels were developed for deep-drawing applications and are similar in composition to type 201 stainless steel. In order to obtain good formability, the rapid rate of work-hardening (characteristic of the 200-series steels) was decreased by the addition of copper. The behaviour of two sets of alloys during fusion welding was investigated: 17Cr-7Mn-4Ni-o.5Cu steels containing 0.001 to 0.27 per cent nitrogen, and 17Cr-7Mn-2Ni-o.1N steels with copper contents varying between 0.01 and 3.11 per cent. Al the steels in these two sets initially solidify as d-ferrite, which transforms partially to austenite during cooling. As the nitrogen level increases, the microstructure of an autogenous-weld metal ranges from large amounts of d -ferrite, martensite, and Widmanstätten austenite, to austenitic structures with small amounts of vermicular d -ferrite. The formation of d -ferrite during solidification and the presence of ferrite retained in the weld metal indicate that the experimental alloys will not be susceptible to hot cracking during welding. Except for the alloy with 0.27 per cent nitrogen, the resistance to pitting corrosion of the experimental steels in the as-welded condition is inferior to that of type 304 stainless steel. None of the experimental steels is susceptible to intergranular attack in the as welded condition. The alloys with 0.19 and 0.27 per cent nitrogen have properties (corrosion and microstructure) similar to those of type 304 stainless steel in the as-welded condition.

Jan 1, 1996

By S. Moolla, R. Lynch, S. Brijraj

A reliable method to locate microseismic evets is an important objective for routine mine seismic monitoring. We developed an algorithm that can automatically and reliably locate an event from a single uniaxial trace. Signals created by microseismic events are recorded as seismograms that consist of direct P- and S-waves as well as the waves reflected off the underground excavations. We take advantage of the extra complexity these reflections introduce as they make the signal more unique. In our investigation we cross-correlated unaltered synthetic seismograms against trial waveforms created from a linear combination of appropriate waveforms from a library of numerically calculated strain Green’s tensors. We use a single uniaxial synthetic seismogram to invert for the source location, six moment tensor components, and frequency. The resulting cost functions are constructed as maximal correlations at each node in the mine grid through the true source x-planes. This function is maximized by differential evolution to simultaneously yield the source parameters. Sensitivity tests such as shifting the mine plans and altering the background velocities of the media are investigated to test the robustness of the method. We contaminate the data with 40% white noise to test the resolution against simulated real recorded seismograms. The method is demonstrated using synthetic data calculated with a realistic underground 3D velocity model.

Jun 10, 2024

By t. Knezicek

Tuzla Coal Basin in Bosnia and Herzegovina is the largest coal area in the State. Regional mining industry sensed the need for mining machinery database development in order to achieve easier planning purposes and equipment selection for open cast mines in Tuzla Coal Basin. Several databases for mining machinery used on the bituminous deposits, i.e. on brown coal and lignite mines, were developed at the Faculty of Mining, Geology and Civil Engineering, Tuzla. System Development Method was used as the approach to the database development, generating relational structure of database. First database was established for trucks and was presented as simple table, drawn and filled on the paper sheet. In the next phase, data were stored in spreadsheet type software (Quattro Pro and Excel). Lately developed database is Bucket Wheel Excavator database designed in MS Access. Two concepts, spreadsheet and Access, were integrated into one large database, enabling manipulation of hundreds of data at one place. Required adaptations of existing database in MS Access, enables Access to be used as an integration resource. Database is designed to reserve free memory for input data for mining equipment not considered so far, such as spreaders, crushers, belt conveyors, tripper cars, etc. New, integrated database, at this stage, can be imported to any type of commercial or individual software where needed. Mining machinery integrated database for open cast mine operations is under going testing in a State company, Coal Mines Tuzla. Keywords: Tuzla Coal Basin, machinery database, SDM, relational database

Jan 1, 2003

By I. V. Samarasekera, E. B. Hawbolt

A review of recent work being conducted at the university of British Columbia on the modeling of the microstructural evolution during the hot rolling of steel is presented. A mathematical model of heat transfer was developed to describe the thermal field in a slab during rough and finish rolling. The model for rough rolling, discussed in this review, also simulates the growth of oxide scale on the slab surface. To quantify the heat transferred from the slab to the work rolls, instrumented samples of MSI3O4 L stainless steel, 0,05 per cent carbon steel, and 0,05 per cent carbon steel with 0,025 per cent

Jan 1, 1995

By T. P. Chidakwa, T. R. Stacey

This study investigated the corrosion rates of various steel types and coatings used for friction rock stabilisers in a deep-level gold mine under diverse underground environmental conditions. Testing was conducted in situ within ramps, intake airways, and exhaust airways, and through simulated laboratory experiments. Results revealed that environmental variations significantly influence the corrosion performance of different materials and coatings. Duplex coatings, made up of galvanised steel with an organic paint layer, demonstrated the highest corrosion resistance. Zinc-based coatings provided moderate protection, while 3CR12 stainless steel and uncoated S420 carbon steel exhibited comparatively poor resistance under both aqueous and atmospheric conditions.

Mar 4, 2025