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1. Book reviews Tungsten: 1982. London, Mining Journal Books Ltd, 1982. 179 pp. Reviewer: G.A. Brown The geology of industrial minerals in Canada, edited by G.R. Guillet and Wendy Martin. Canadian Institute of Mining and Metallurgy, special volume 29. Reviewer: R.W.O. Kersten Foam flotation - theory and applications, by Ann N. Clarke and David J. Wilson. New York, Marcel Dekker, 1984. 418 pp. Reviewer: B.K. Loveday Industrial and financial indicators of the steel industry, by Patrick Genevaz. Paris, La Chambre des Cartes, 1982. 2 vols. Vol I: Analysis and conclusions, FF3500. Vol. 11: Tables, FF4000. Reviewer: R.J. Dippenaar An encyclopaedia of metallurgy and materials, by C.R. Tottle. Plymouth, Macdonald and Evans and The Metals Society, 1984. 481 pp. RI44,50. Reviewer: P. T. Wedepohl The role of crack growth in metal fatigue, by LP. Pook. London, The Metals Society. Reviewer: C.A. Boothroyd Hydraulic coalmining - new technology and its geological and industrial significance, by H.C. Siebert. Hamm, Zentraldruckerei BAG, 1984. 33 pp. Hydraulic coalmining - hydromining update: potential impact on coal deposits and coal mining industry, by H.C. Siebert. Hamm, Zentraldruckerei BAG, 1984. 130 pp. Victoria's brown coal. A huge fortune in chancery, edited by J .T. Woodcock. The Australasian Institute of Mining and Metallurgy, 1984. 204 pp. Reviewer: J.J. Versluis 2. Canadian publications The following reviews of the activity and developments during 1982 in respect to the chief minerals produced or consumed in Canada are now available. Zirconium. An important mineral commodity. Mineral Policy Sector, Mineral Bulletin MR 202, $6.60. Canadian minerals yearbook 1982. Mineral Policy Sector, Mineral Report 32, $40.75. Canadian reserves of copper, nickel lead, zinc, molybdenum, silver and gold as of January 1, 1983, by W.H. Laughin. $4.20. Mineral Policy Sector, Mineral Bulletin MR 201. Sulphur market profile, by B.W. Boyd. Mineral Policy Sector, MRI 84/5. 3. Mintek publications Report M123 The use of of activated charcoal in a NIMCIX column for the recovery of gold from cyanide solutions. Report M150 Energy transfer in the hearths of submerged-arc furnaces. Report M151 A preliminary investigation of the initiation of pitting corrosion in austenitic stainless steels and nickel-based alloys. Report M154 The reduction of Winterveld chrome spinel at 1300°C under an argon atmosphere in the presence of carbon. Report M165 The development of an improved on-line gold analyser. Report MI67 three nebulizers for use with an inductively coupled plasma spectrometer. 4. New publications Mineral Industry Consultants Association (as at 31st March, 1984). Parkville (Australia), The Australasian Institute of Mining and Metallurgy, 1984. 112 pp. Philosophical and procedural guidelines for the planning professions. Johannesburg, the Environmental Planning Professions Interdisciplinary Committee (EPPIC, P.O. Box 61019, Marshalltown 2107), R2.50. Directiona//y solidified materials for high temperature service, by M. McLean. London, the Metals Society, 1983. 337 pp. Tin and its uses no. 142. Greenford (England), International Tin Research Institute, 1984. Metals engineering International Symposia & Exhibitions Ltd - a subsidiary of Industrial Newspapers PLC - are pleased to announce that they will be organizing a mammoth engineering event, entitled Metals Engineering 86, comprising five important exhibitions in 1986:. Agglomeration A major symposium on agglomeration is being organized in Toronto for the 2nd to 5th of June, 1985. Speakers from around the world (Canada, U.S.A., Brazil, Australia, Japan, West Germany, Italy, India, China, Switzerland, Poland, Yugoslavia, and France) will address delegates on various aspects of agglomeration relative to iron ore, coal, coke, and fuels. Plenary theme papers will also be presented by speakers from Japan, the U.K., and the Netherlands.

Jan 1, 1985

By R. Pretorius, N. Mautsa

In a cobalt precipitation plant, phosphoric acid is used to eliminate excess uranium from the pregnant leach solution, resulting in a cobalt hydroxide product that has little uranium contamination. However, the amount of phosphoric acid added must be monitored and controlled to avoid financial and sustainability impacts and to prevent negative impacts on the final product quality. One possible solution to this problem is the use of online residual phosphorus measurement techniques to regulate the addition. By continuously monitoring the residual phosphorus levels in the solution, the plant can adjust dosing in real time to maintain the target residual phosphorus level. As a result, the cobalt precipitation plant can improve phosphorus level control, lowering the risk of overdosing, and ensuring consistent product quality. This approach can also improve process efficiency, reduce operational costs, and have a positive environmental impact

Jan 1, 2023

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. M. Venter, C. W. Siyasiya, N. K. K. Arthur, M. G. Willemse, D. Marais

Although additive manufacturing is fast gaining traction in the industrial world as a reputable manufacturing technique to complement traditional mechanical machining, it still has problems such as porosity and residual stresses in components that give rise to cracking, distortion, and delamination, which are important issues to resolve in structural load-bearing applications. This research project focused on the characterization of the evolution of residual stresses in Ti-6Al-4V extra-low interstitial (ELI) additive-manufactured test samples. Four square thin-walled tubular samples were deposited on the same baseplate, using the direct energy deposition laser printing process, to different build heights. The residual stresses were analysed in the as-printed condition by the neutron diffraction technique and correlated to qualitative predictions obtained using the ANSYS software suite. Good qualitative agreement between the stress measurements and predictions were observed. Both approaches revealed the existence of large tensile stresses along the laser track direction at the sections that were built last, i.e., centre of the top layers of the samples. This in addition leads to large tensile stresses at the outer edges (corners) which would have the effect of separating the samples from the baseplate should the stresses exceed the yield strength of the material. Such extreme conditions did not occur in this study, but the stresses did lead to significant distortion of the baseplate. In general, the microstructures and spatial elemental mapping revealed a strong correlation between the macro-segregation of elemental V and the distribution of the β-phase in the printed parts.

Feb 6, 2023

By M. J. Latva-Kokko, CA Snyders, J. R. Peltola, M. K. Kostiainen

It is well known that carbon management is essential for minimising soluble gold losses in carbonin- leach (CIL) and carbon-in-pulp (CIP) circuits. Even so, carbon measurements remain predominantly a manual operation with a low amount of control and automation around CIL and CIP reactors. Carbon inventory, i.e. knowing the carbon concentration in each reactor, is crucial for good carbon management. CarbonSense, a novel in-situ measurement system, was therefore developed for continuous monitoring of the carbon concentration in each reactor and paves the way for more advanced control in gold operations. The carbon management and optimisation system is based on Outotec® HSC Sim dynamic process simulations where each process component is modelled in detail. Generated models are validated with real data from a particular operation. The simulator will allow for the carbon control sequence to be realistically tested and the efficiency optimised by controlling the feed and discharge pumps in a hazard- and risk-free process environment. Furthermore, by combining CarbonSense and Outotec® gold courier (online soluble gold measurements) continuous feed-forward and feedback information can be obtained. The optimiser will then define the best running parameters based on the cost function of gold production versus intrinsic factors such as utility costs and adsorption time. Eventually, the application can be installed parallel with a real process island and it can be continuously calibrated with real-time process data. The dynamic model will then create future predictions for the entire process island. The example case presents a CIL circuit, which is simulated using Outotec® HSC Chemistry Sim and operated through Outotec® ACT (Advanced Control Tool) application. Keywords: Carbon-in-leach, CIL, CarbonSense, carbon management, automated control, simulation

Jan 1, 2020

By H. Karabulut, S. Gündüz, K. Karacif, M. A. Erden

The corrosion properties of iron-based composite materials containing graphite and silicon carbide (SiC) reinforcement were investigated. The effects of silicon carbide reinforcement were investigated by adding 0.5% graphite and 1%, 2%, and 4% SiC. A powder metallurgy method was used to produce the composite samples. Iron, graphite, and silicon carbide powders were blended for one hour with a threeaxis mixer and then unidirectionally pressed under a pressure of 750 MPa. After pressing, the composite materials were sintered at 1100°C for one hour. The corrosion properties and microstructure, density, and hardness properties of the composite materials that can affect the corrosion properties were also investigated. It was determined that the pore ratio and hardness of the composite material increased, and corrosion resistance decreased, with increasing silicon carbide content.

Jun 2, 2022

By S. Banisi, S. M. Mousavi, S. D. Tafvizi, Gh. A. Parsapour, M. Mahmoudi

Generally, regrind circuits are used to increase the degree of liberation of value minerals which are fed to flotation circuits. At the regrind circuit of the Sarcheshmeh copper complex, four ball mills are in closed circuit with their hydrocyclone clusters. In the initial design of the plant, feed and underflow percent solids, and pressure drop of the hydrocyclones were 39% and 65%, and 15psi, respectively. Over the years, due to a reduction in the feed grade from 1.17% to 0.67% and changes in the operational conditions, the feed rate to each hydrocyclone cluster has decreased from 401 to 70t/h and consequently the pressure drop, feed and underflow percent solids have reduced to 4psi, 17% and 25%, respectively. The main objective of this research was to audit the feed solids concentration and pressure drop of the hydrocyclones and make the necessary modifications based on the Plitt’s model. The results of sampling showed that water recovery to underflow was 59% which was higher than normal values. By reducing the number of operating regrind mills from 4 to 2, the feed rate to each mill increased. After this modification and taking necessary measures in the plant to implement the new operating approach, the pressure drop, feed and underflow percent solids increased to 18psi, 28% and 58%, respectively. The water recovery of the hydrocyclones underflow decreased from 59% to 12%. These changes in addition to increasing the circuit efficiency saved 1000 kWh energy and decreased ball consumption by 925 ton/year because of reduction in the number of operating ball mills. Keywords: Regrind mills, flotation, audit, troubleshooting

Jan 1, 2020

By C. R. S. Needes, M. J. Nicol, G. T. W. Ormrod, N. P. Finkelstein

The industrial application of a dioxide electrode uranium by C. R. S. NEEDES, Ph.D. (London) (Visitor), M. J. NICOL, Ph.D. (Rand) (Visitor), N. P. FINKELSTEIN M.Sc. (Rhodes), Ph.D. (Liverpool) (Fellow), and G. T. W. ORMROD (Visitor) A correlation between the potential of a U02 electrode and the rate of recovery of uranium has been proved in laboratory and plant trials. When the recovery rates change because of variation in the concentrations of Fe(III), Fe(II), SO4 'and H+, a positive correlation is observed. However, an 2- increase in the concentration of phosphate in solution produces an increase in the U02 electrode potential but a decrease in the rate of leaching of U02. The correlation between the U02 electrode potential and the rate of leaching of U02 is then negative. It is concluded that, as a control device, the electrode cannot compete with the platinum electrode for use on certain plants. Nevertheless, the U02 electrode will act as a useful warning device if the total concentration of iron in solution decreases to below a level concomitant with the economic recovery of uranium. Furthermore, because of the positive correlation between the U02 electrode potential and the phosphte concentration, the electrode will also be of value in the detection of an increase in the phosphate level in solution. When it was incorporated in a suitable industrial probe, the electrode was found to be able to withstand the rigours of the leaching conditions in a large pilot-plant pachuca, and only failed after six weeks' operation.

Jan 11, 1975

Council and Standing Committees - 1981/82 President: G. Y. Nisbet. Senior Vice-President: Prof. A. N. Brown. Junior Vice-President: Prof. R. P. King. Honorary Treasurer: Prof. D. G. Krige. Immediate Past President: Dr P. R. Joehens. Members of Council: B. C. Alberts, J. D. Austin, P. T. Fewell, C. E. Fivaz, J. J. Geldenhuys, Dr A. K. Haines, P. N. Harris, H. E. James, C. G. Knobbs, Dr B. K. Love¬day, Dr J. Lurie, C. S. MacPhail, D. G. Malan, J. C. Mostert, G. C. Thompson, Dr H. Wagner. Chairman, Witbank/Middelburg Branch: B. Rohrmann. Chairman, Orange Free State/Klerksdorp Branch: K. F. W. Eick. Chairman, Materials Engineering Specialist Division: G. Pienaar. Past Presidents serving on Council: Dr M. G. Atmore, H. Britten, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plewman, Dr R. E. Robinson, Prof. M. D. G. Salamon, P. W. J. van Rensburg, D. A. Viljoen, P. A. von Wielligh. Standing Committee Chairmen: Constitution, Rules and Policy, Dr P. R. Jochens; Membership, Prof. R. P. King; Training, Career Guidance and Education, P. A. von Wielligh; Journal, Prof. A. N. Brown; Monograph Series, D. G. Malan; Technical Programme - Metallurgy, C. E. Fivaz; Technical Programme - Mining, P. N. Harris; SAIMM Schools - Metallurgy, Dr B. K. Loveday; SAIMM Schools - Mining, J. D. Austin; 1982 CMMI Congress, Dr M. G. Atmore; Awards, Dr P. R. Jochens; Adjudication, Dr P. R. Joehens; Phoenix National Committee, Dr M. G. Atmore; Excursions, J. C. Mostert; Mines and Works, Prof. A. N. Brown; World Mining Congress - National Committee, Prof. R. P. Plewman.

Jan 1, 1982

By N. Naude, W. P. Roux, O. Kaba

Ceramic filtration plates are used for dewatering slurries with high solid concentrations and particles in the size range of 30 μm to 150 μm. After extensive operating times, the ceramic filter plates at Minas Rio in Brazil begin to blind due to the precipitation of barium sulphate on the surface of the ceramic filter plate, which reduces the overall efficiency of the filtration process. Further research is needed to identify the barium precipitate phases on the blocked filter plates and its thermodynamic and kinetic behaviour in the system. A crystallography analysis was performed on the sample and the results showed that there are two different sets of precipitates formed on the filter plate: grey crystals which were large and scatted on the filter plate and red micro crystals that covered the entire surface of the filter plate. The red microcrystals on the sample were identified with XRD, which indicated that the sample contained barium sulphate in the mineral form barite. Experiments were conducted to determine the optimum conditions under which barium precipitation will occur. The conditions tested as a possible driving force for barium sulphate precipitation were the effect of temperature, pH and concentration. The pH and temperature ranges were pushed to both the lower and higher boundaries. The effect of temperatures as low as 15oC was studied and pH levels of 7 and upwards. The first nuclei started appearing at a pH of 7 but significant growth is promoted at higher pH levels. The X-Ray diffraction analysis confirmed the phase of the precipitates formed, and the orthorhombic crystallographic structure formed is a characteristic of barium sulphate. Keywords: Iron ore, barium sulphate, temperature, pH, concentration, morphology, and ceramic filter plate

Jan 1, 2020

By F. Petersen, W. van Dyk, J. Bonsu, A. Isafiade

"This paper aims to demonstrate how a systemic approach can be applied to the analysis of the causes of accidents in South African mines. The accident analysis framework used was developed previously by the authors from the combination of the Mark III version of the Swiss Cheese model, Incident Cause Analysis Method (ICAM), the Nertney Wheel model, and safety management principles. Data on 91 accidents occurring from 2010 to 2012 at the site of a platinum mine in South Africa were used to populate the newly developed framework. The results obtained show that while routine violations (45% of all accidents analysed) were the most common form of human error, problems in the physical environment of workers were the most common workplace factor (39.6% of all accidents analysed). Furthermore, inadequate leadership was found to be the most common systemic factor responsible for accidents (51.6% of all accidents analysed). Some workplace factors were more commonly associated with particular unsafe acts than others, and some systemic factors were more associated with particular workplace factors than others. The outcome of this study demonstrates that systemic factors, rather than human errors and violations, are the chief causes of accidents in the mining sector. IntroductionThe mining industry is a very important sector of the South African national economy. A major factor threatening the sustainability of this industry is mining accidents, which frequently result in injuries or deaths, destruction of property, and pollution of the environment. In the past, mining accidents have led to the shutdown and threat of shutdown of mines (Ryan, 2008; Mail and Guardian, 2011). The country stands the risk of incurring significant losses if the mining industry continues to experience shutdowns. In 2012, the mining sector accounted for R262.7 billion (equivalent to US$32.83 billion) representing 8.3% of GDP directly, on a nominal basis (Chamber of Mines of South Africa, 2013).Mining safety is a global concern and has attracted significant international attention. This has precipitated various studies into different aspects of mining. Unfortunately, human error has been blamed for the majority of these accidents. A study by the US Bureau of Mines found that human error is the cause of almost 85% of all accidents (Patterson and Shappell, 2008). In Australia, it is the cause of two out of every three occupational accidents (Patterson and Shappell, 2008). Various mining companies maintain that they run efficient systems, and hence the behavioural problems of workers are to blame for most accidents. An understanding of accident causality could be a major step in the quest to reduce accidents. Only with a good understanding of the accident process can effective remedies can be designed."

Jan 1, 2017

By M. Splaine, W. Davison, D. C. Atkinson

"Since 1964, Nchanga Consolidated Copper Mines, Ltd., has been developing and using production scheduling methods for optimizing its metallurgical operations in the short term (up to one year). Medium-range metallurgical planning has been possible only by successive evaluations of a single-year L.P. A modified version of Rosenbrock's direct search technique has now been developed to allow multi-year optimization of both mining and metallurgy for medium-range planning. The modifications to the search technique have produced a marked increase in computational efffciency for this heavily constrained problem in many variables and the system is a usable planning tool, given a reasonably powerful computer. The plans are 'optimum' in the sense that they yield the maximum present value of the operations.Each of the resulting five-yearly mine plans forms the basis for further detailed metallurgical evaluation by the established production scheduling system."

Jan 1, 2014

By T. R. Marshall

SAMREC (The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves) Clause 7 notes that ‘Documentation detailing Exploration Results, Mineral Resources and Mineral Reserves from which a Public Report is prepared must be prepared by, or under the direction of, and signed by a Competent Person.’ Similar statements with respect to Competent Valuators (CVs) and Qualified Reserves Evaluators (QREs) are contained in the SAMVAL (South African Code for the Reporting of Mineral Asset Valuations) and SAMOG (South African Code for the Reporting of Oil & Gas Resources) codes respectively. What does it mean to be a Competent Person (CP) in the context of compiling/signing-off on SAMCODE (South African Mineral Code) compliant documents? What do the registration and experience requirements mean? Who is ultimately responsible for the report and what does such responsibility prescribe?

Sep 1, 2021

By E. Arghavani, S. H. Amiri, S. Zare, F. Sepehri, M. Ramezanizadeh

Mineral processing plants include different stages like crushing, grinding, classification and concentration, all of which have partially affect the final product. To identify and solve the related problems of each stage, process audition should be carried out continuously to find the major solutions of improving product and decreasing the maintenance and operating costs. The Iranian Gohar-Zamin iron ore beneficiation plant consists of equipment such as gyratory and cone crushers, high pressure grinding rolls (HPGR), ball mill, dry and wet double-deck vibrating screens, hydrocyclones cluster, magnetic drum separators, thickener and horizontal vacuum belt filters. The defects of initial design as well as current non-standard operating conditions of equipment were monitored and detected and the opportunities for process optimisation were presented as follows: establishing the control loop of power draw for cone crushers, the modification of feeding chute in cone crushers to minimise the non-uniform wear of parts, removing segregation in the fresh feed bin and screen’s circulating load chute in order to provide the proper feed to HPGR, reducing wear rate on HPGR rolls surfaces, decreasing the amount of rejected materials in screen, equalising the solid content and particle size distribution (PSD) of feed in all magnetic drum separators and equalising the PSD of hydrocyclones overflow. This paper provides a guideline for the mineral processing industry to focus its efforts on process design to deliver the efficiency with minimum capital costs. Keywords: Process audition, gyratory crusher, cone crusher, HPGR, screening, hydrocyclones, magnetic drum separators

Jan 1, 2020

By M. Z. Emad, S. Raza, K. Jalil, M. A. Raza, M. U. Khan, S. A. Saki

Dimension stone mining is Increasing because of growing demand from the building and construction industries. Diamond wire saw cutting is a popular dimension stone mining technique around the world. Estimation of the production cost for this method is critical for these operations. n this research a production cost model was developed for the mining of granite using a diamond wire saw. Cost and production data were collected from a granitic dolerite operation in Pakistan for a 4.5-year period, and analysed to identify the cost components. Fuel (34%), labour (15%), consumables (40%), and maintenance (5%) were found to be the four major cost components in this operation. A regression-based dimension stone production cost model incorporating statistically significant variables was developed. The data presented a strong correlation of production cost with fuel, labour, and consumables costs. Finally, a production cost model based on the consumption cost of diamond wire is presented. The model was verified using actual production cost data, which indicated 95% (R2 = 0.95) variance in the data between the predicted and actual production cost values. The model may help field engineers in computing their dimension stone operational cost during the cutting phase.

Nov 6, 2023

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 A. Rödfalk, P. Bloemer, J. P. Nilsson, N. Brogden

"Reliable and accurate metal transfer information during silicon tapping from an EAF is invaluable for decision-making and process optimization, while obtaining such information safely is a necessity.Elkem Thamshavn Norway, a producer of metallurgical-grade silicon, identified inherent safety problems with gauging fill levels in ladles using dip bars while molten metal was continuously pouring from a rotating EAF. Operator safety was a paramount concern, and an alternative automatic method of controlling the tapped fill level needed to be found.It was also considered that further benefits could be achieved such as monitoring the tapping flow from the EAF in order to identify any clogging, as well as the potential to use the live feed from such a system to assist decision-making regarding work around the taphole area.Agellis Group AB, Sweden, a company with over 30 years of experience in gauging molten metal levels in the metals industry, was able to design a solution for Elkem Thamshavn that would provide the required real-time process data while enhancing operator safety.This paper shows how the Agellis AB EMLI-L system was successfully installed at Elkem Thamshavn’s EAF continuous tapping area, how ladle fill levels were constantly monitored, and how full ladles were replaced by empty ones without the need for operators to be in the tapping area to take level readings. The results were used to compare the accuracy and reliability of Elkem Thamshavn’s current measuring methods with that of the EMLI-L system. The paper also covers how problems such as how to connect, run, and protect cables in and around the EAF tapping area, as well as connector and cabling survivability during the three day refractory pre-bake period, were solved. Finally, the paper discusses the potential production improvements, maintenance requirements, and data integration attainable through the installation of the system, as well as the major safety improvements that have been achieved."

Jan 1, 2014

By D. Odendaal, S. Bharat, R. D. Cromarty

The aim of this investigation was to determine the effect of high-temperature heat treatment on the electrical resistivity of charcoal. Samples of two different wood types (eucalyptus and black wattle) were pyrolised in a retort at a temperature of 700°C and the resulting charcoals heat-treated in an induction furnace at temperatures from 800°C to 1800°C and residence times from 60 to 120 minutes. After cooling, the resistivities of the samples were measured at room temperature using the four-point probe technique. It was found that as the heat treatment temperature increased the electrical resistivity of the charcoal decreased, approaching an asymptotic value at higher temperatures. Longer residence times decreased the resistivity, but this effect was not pronounced.

Oct 3, 2023

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 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