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By Luis Rudolphy, Pekka Tähkiö

"Flotation plant design, construction and start-up can be challenging tasks, because multiple factors and disciplines have to be combined in an efficient manner, in order to execute a project that meets the technical, financial and timeframe expectations. Key considerations that need to be addressed when designing a flotation plant are process requirements, equipment integrability, automation, and up- and downstream processes/designs. Furthermore, several other lifecycle factors need to be considered, such as servicing and maintainability, operational costs, future expansions and decommissioning, among others. To address these challenges, Outotec has developed a new approach to designing flotation plants that targets eliminating most of the inherent risks that can be found in these types of projects. The new Outotec® plant is a fully modular approach in which the above-mentioned challenges have been taken into consideration in the design phase. As a result, the cPlant concept can give several benefits for new and experienced companies involved in the minerals processing business, such as lower risk investments, fast and cost-efficient flotation plant delivery, faster ramp-up period, easy plant expansions, fully automated processes and operation and maintenance ease. As well, dismantling and transportation of the cPlant to a new location is easy and fast, hence the new cPlant concept makes possible to exploit small, short-lifespan ore deposits and also retreat old tailings ponds that might contain valuable minerals and where the ore quantities are limited. Furthermore, cPlant is easily implemented for brownfields and temporary expansions during bigger expansions."

Jan 1, 2015

By C. Chibwe, M. Tadie

Copper electrowinning models are useful for prediction of process performance, optimisation and improved understanding of complex phenomena such as current distribution without the expense of physical experiments. Recently, finite element models such as those generated in COMSOL Multiphysics have been developed for the electrowinning process. The predictive capacity of these models is improved by incorporating physical and chemical phenomena. Since physicochemical properties of electrolytes can have a significant effect on the quality of copper produced, this work was conducted to investigate the effect of such properties on electrodeposition at varying levels of copper, sulphuric acid concentration, iron concentration and temperature, in the presence of a smoothing agent. Tests were conducted at conditions similar to those for industrial copper electrowinning. Mathematical correlations were developed for the following properties; density, conductivity and diffusivity which were compared to existing models in literature and thereafter applied in a COMSOL generated model. The model predicts, current distribution at the cathode surface, deposit thickness (morphology), concentration of species within the cell and current efficiency. Current distribution output shows the impact of several phenomena on the deposit generated including the relationship between increasing copper concentration and current density and lack of influence of acid concentration on this property. Keywords: Electrowinning, physicochemical properties, electrolyte composition, modelling

Jan 1, 2020

By A. V. Rasskazova

Theoretical substantiation of leaching of clustered ultra-fine gold by the electro-photo activated cyanide and chloride solutions is given in the paper; and processes of activation of leach solution by electrolysis and photo-activation are described. Comparative experiments on electro-photo activated leaching of ultra-fine gold from refractory ores by cyanide and chloride solutions were carried out. The material for research is primary ore of the Pogromnoe deposit (Russian Federation, Trans-Baikal Territory). The ore is characterised by the minimum sulfide minerals and the organic carbon content. Gold in ores of this deposit is presented as mainly ultra-fine. Gold inclusions in quartz and silica-alumina minerals (metasomatic minerals) are ultra-fine. Sulfide minerals (2.5-3%) are presented in ore generally by pyrrhotine (gold content does not exceed 10 g/t). Standard cyanide technology provides 49.5% gold recovery. Photo-electro activated air saturated NaCN provides 69.9% gold recovery. Laboratory research of chloride-hypochlorite column leaching demonstrated that the electro-photo activated method provided 78.9 % gold recovery to pregnant leach solution. Chloride-hypochlorite photo-electro activated solution can provide higher level of gold recovery with shorter process duration (10 days) in comparison with cyanide (40 days). The final decision regarding the choice of leach solution has to be done on the basis of technical and economic calculations. Keywords: Ultra-fine gold, cluster chemical reactions, active clusters, leaching, electro-photo activation of leach solution

Jan 1, 2020

By A. A. Oakes, P. M. C. Wilson

This paper describes some aspects of the planning of a new colliery which commenced production in the Middleburg district in 1966. An account is given of some of the problems encountered in the early years of operation and of what was done to solve them. The conclusion is reached that design of plant and machinery should be flexible to permit multiplication of units.

By H. W. Read

The South African platinum industry finds itself in the midst of a rapidly evolving society that is no longer characterized by the apparent stability of the previous decades. The features of this society include increasing global competition, rapid technological innovation, a declining skills pool, major political transformation, a more challenging working environment as the mines reach deeper into the earth?s crust and a greater concern for human welfare. It is therefore axiomatic that new ways will have to be found to engage the all-pervasive change in the mining environment. Although in general terms project management is a universal endeavour for managing change, it takes place in a specific socio-techno-economic environment and geographical setting that gives it a particular context. The argument of this paper explores, analyses and synthesizes the impact of these changes on the emerging project management methodology. In essence, the management of change will inevitably contribute to the emergence of new dilemmas, issues and challenges. The change management process and procedures will also be affected by this change and in response, drive internal change of its own structures and organization. And, therefore, a new paradigm of project management will become apparent. A new project management model will then be proposed to the industry.

Jan 1, 2006

By M. C. Harris

Float-sink analysis has wide application in the coal laboratory. This paper evaluates the established methods used for the float-sink analysis of fine coal, and then describes a new method and apparatus that can be used for material down to a few micrometres in size. The method is rapid and accurate, and requires only a small amount of sample. The results presented show close agreement with the float-sink analyses obtained by the more classical technique using separating columns. The new centrifugal method reduces the time required for the analysis by a factor of ten.

Jan 1, 1986

By L. A. Jagger

The world?s second largest producer of platinum, Impala Platinum Ltd, approved two new twin shaft projects at the end of September 2004, Nos. 16 and 20 Shafts. Both shaft projects are stand-alone entities and are being sunk from surface. Previously Impala had embarked on a strategy of extending the life of its third generation shafts by means declines. No. 16 Shaft is the first of a new fourth generation shaft complex, while No. 20 Shaft is the last of the third generation type shafts in the so-called shallow to intermediate mining zone. This paper details the basic designs of each project and covers the initial implementation. Although both projects are twin shaft systems, the access methods from the shafts to the reef horizon differ. Initiatives implemented to speed up the projects are also briefly covered.

Jan 1, 2006

By A. L. Bleloch, A. M. Starfield

This paper is concerned with heat flow in the plane of a typical cross-section of a deep underground airway. A new algorithm, called the quasi-steady method, is presented for the calculation of rock temperatures in that plane. The algorithm is used in the computation of heat and moisture transfer rates from the rock to the ventilating air for an airway that is wet on part of its circumference and dry elsewhere. The speed and accuracy of the new method are demonstrated on a microcomputer, and it is argued that this method offers a considerably more versatile and physically meaningful alternative to previous methods for the prediction of increases in air temperature along mine airways. The algorithm is also used to explore the concept of a uniformly wet airway that is equivalent to a partly wet airway in terms of its effect on the ventilating air. The concept is shown to be reasonable, but more complex than one might have anticipated. Finally, several useful extensions and applications of the new method are suggested.

Jan 1, 1983

By S. K. Gilman, P. S. Marcos

There are basic areas of importance within a concentrator or mineral separation plant, which require focus to ensure acceptable recoveries, throughputs remain at an acceptable level and product grades meet specification. Professional and para-professionals within the mineral sands industry are in demand due to the booming resource sector. Added to this, new mineral sands operations are being commissioned straining the industry further. These factors have increased staff turnover and introduced many new people to the industry. It is essential these new entrants are armed with basic plant troubleshooting skills relevant to the minerals sands industry to minimize production lost through poor recoveries. Mineral sands processing does not involve highly technical or sophisticated unit processes. However, success is often slow to arise due to a lack of detailed understanding, as well as managing multiple interrelated unit processes within a plant. Fundamental background physical conditions (such as equipment loading and water quality) must be met for unit processes to be efficient. Technical management of these process plants should always include observation of these background conditions for they often provide the answer to underperformance. Examples are presented with an indication of the possible effects on recovery and product grade.

Jan 1, 2007

By E. J. McLean

Gold mineralisation at Bendigo is exclusively associated with quartz reefs, commonly found within or near anticlinal fold hinges. The gold is typically coarse grained (0.5 mm to 5 mm), free milling and displays a complex, nuggetty distribution within the veins. This ore is highly amenable to gravity recovery processes. As the Bendigo operation is not permitted to treat whole ore by a cyanide leach/CIL circuit, the flow sheet is more complex than conventional gold recovery circuits. Primary gold recovery is from a gravity circuit closing the grinding circuit to a bulk gravity concentrate and from a flotation circuit treating cyclone overflow to a bulk float concentrate. The plant capacity is relatively low by current gold industry standards at 600 000 tpa. Re-establishing gold production at Bendigo has presented several challenging, and sometimes competing, issues in process design and operation. The mine, process plant, associated services and infrastructure are at Kangaroo Flat, a low density, semi-rural zone in the southern urbanisation of the Bendigo metropolitan area. One of the main processing challenges during the design was the competing comminution requirement to avoid over-grinding, which would flatten or smear the characteristic nugget gold and hinder effective gravity gold recovery, whilst also providing sufficiently well liberated particles that would respond well to flotation. Important, non-metallurgical challenges were to minimise impacts on the local community from noise, dust, air emissions, visual impact, water egress and off-site traffic.

Jan 1, 2007

By L. Cong, C. Liu, N. Zhang, W. Cao, C. Zhou, X. Fan

"The modes of occurrence of arsenic and the effects of low-intensity leaching-flotation on arsenic removal from coal slime from the Tanggongta Plant, Inner Mongolia, China were investigated. The coal slime was examined using hydride generation inductively coupled plasma optical emission spectrometry and X-ray diffraction to obtain the content of elements and the major minerals. The modes of occurrence of arsenic in minerals were determined using selective leaching, float-and-sink analysis, and polarized light microscopy. The results indicate that pyrite is the dominant carrier of arsenic in the coal slime, which predominantly exists in association with clay. Significant proportion of the arsenic is removed by a low-intensity leaching-flotation process, consistent with the data from selective leaching and flotation of gangue. The results show that low intensity leaching-alkali washing-flotation is more efficient than direct flotation and low-intensity leaching-flotation.IntroductionUnderstanding the occurrence of arsenic in coal and its removal is significant in optimizing coal utilization, because arsenic in the environment is viewed as a potentially toxic trace element (Finkelman, Belkin, and Zhang, 1999; Hall, 2002; Smith et al., 1992; Smedley et al., 2003; Zheng et al., 1999). Many studies on the modes of occurrence and concentration trends of arsenic in different coal and washing products have been performed (Diehl, Goldhaber, and Hatch, 2004; Kolker et al., 2000; Quick and Irons, 2002; Wang et al., 2006; Fan et al., 2016). Trace elements are usually preferentially associated with certain minerals and the form that these minerals take will influence the efficiency of removal during cleaning (Quick and Irons, 2002). Arsenic is mainly associated with minerals such as pyrite, carbonate, and silicate (Demir et al., 1998; Diehl, Goldhaber, and Hatch, 2004; Zhou et al., 2014). The existence of organically bound arsenic was also confirmed using X-ray absorption (Kolker et al., 2000). However, inorganic arsenic is the principal source of pollution because of its leachability and high concentration compared with organic arsenic (Fujino et al., 2004; Gao, Lu, and Wang, 2010; Jiang et al., 2008; Kolker et al., 2000)."

Jan 1, 2017

By G. R. Addie, A. S. Roudnev

The Hydraulic Institute has completed the task of developing a new ANSI/HI standard 12.1-12.6 (2005) for rotodynamic (centrifugal) slurry pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of the different slurry pump types and contains an extensive section on pump and slurry definitions. The effect of slurry on pump performance is covered along with the pumping of froth. Reference is also made to ANSI/HI standard 9.6.7 (2004), which contains anew method for pump performance correction when handling viscous fluids. Classification of slurry services is established and then is used to determine limitations on velocities and total head per pump in order to obtain acceptable wear performance. The new service class, head per stage and other limits are directly related to capital and other cost considerations that will affect solids transport system economics. The writers review the contents of the new standard, highlight the main points, and discuss the reason for the slurry classification, corresponding limits and expected implications, particularly with respect to operating costs of the pumps in solids transport systems.

Jan 1, 2007

The Gold Medal of the Institution for Mining and Metallurgy for 1978 was awarded to Adriaan Louw at the Annual General Meeting of that Institution in London on 17th May, 1979. The award was made for distinguished services to the mining industry in South Africa.

Jan 1, 1979

Each year the South African Institute of Mining and Metallurgy offers a prize (or prizes should the entries warrant it) of up to RlOO for the best paper or dissertation on a topic appropriate to the interests of the Institute. The competition is open to all Student Members of the Institute. A Student Member who is in fulltime study at a university may submit the dissertation or thesis he has to write in part fulfilment of his university degree, provided that it is presented in a manner and on a topic suitable for publication in the journal. Entries for 1976 should reach the Institute by 31st December, 1976.

Jan 10, 1976

A prize awarded by the SAIMM for outstanding academic achievement by 4th-year and 5th-year diplomates at technikons was instituted several years ago. The Senior Vice-President, Mr J.D. Austin, accompanied by the Institute's Secretary, Mrs D. Gardner, attended a prize-awarding function in the form of a luncheon at the Hotel School of the Technikon Witwatersrand on the 25th May.

Jan 1, 1984

By M. Mpofu, B. Maphalala, S. Khan, S. Ngobese, D. Roberts

This paper details an assessment of stemming practices at a South African opencast coal mine and their influence on ground vibration and air blast. Quantitative and qualitative analysis methods were used for the study. The parameters assessed for the quantitative analyses included stemming length, stemming material type, blast-hole depth, burden, and spacing. Pre-blast data from the mine was analysed to determine the deviation between actual and mine design stemming parameters. Mine design stemming length was also compared to the rule-of-thumb stemming lengths. Peak particle velocity (ground vibration) and air blast data from seismograph stations around the mine was analysed to determine the correlation between stemming length and excessive ground vibration and air blast. The qualitative analysis involved observations of blasting procedures at the mine to determine compliance with mine procedures. Some level of non-compliance of actual stemming parameters to design stemming parameters was found, which initially suggested that non-compliance may have contributed to excessive air blast. However, further analysis of the seismograph results indicated no direct correlation between stemming length and excessive air blast and ground vibration. Since stemming parameters are interrelated, it is crucial that all blasting procedures, including stemming, are executed in accordance with best practice, and recorded accurately. There is a need for digital systems for capturing on-bench blasting parameters, as the currently used manual data recording and reporting systems are inefficient and prone to error. Improvements to blast designs are possible through efficient and accurate data recording and reporting systems.

Jan 1, 2021

World refrigeration expert Professor Gunter Heinrich, at the invitation of the School of Mechanical Engineering at the University of the Witwatesrand (Wits), recently addressed industry representatives in Johannesburg on alternative refrigerants.

Jan 1, 1994

By B. S. Xakalashe, M. I. Khama, Q. G. Reynolds

The carbonaceous reduction of manganese ore is an energy-intensive process that releases large amounts of pollutant gases. In an attempt to circumvent the greenhouse gas emissions, this research investigates hydrogen as an alternative reductant. The reduction of manganese ore with hydrogen results in the structural changes in the intermediate products, which might limit the diffusion of the reactant gases through the pores. Computational fluid dynamics (CFD) models capture the structural changes and predict the rate controlling mechanism and this is key in designing the prereduction reactors. The current work uses CFD models to predict the degree of reduction in a shaft furnace under hydrogen reducing conditions. Manganese ore is described as a collection of scalar and tensor fields such as thermal conductivity of the porous medium, density, and viscous resistance. The results indicate that advection contributes significantly towards the overall transport of hydrogen to the reaction sites. Porosity of the final product was found to be higher than porosity of the raw material.

Mar 4, 2025

R. T. Whillans and D. A. Cranstone. Canadian reserves of copper, nickel, lead, zinc, molybdenum, silver and gold as of January 1, 1979. Hull (Canada), Canadian Government Publishing Centre, 1980. C$2.40. Brewer, Stephen. Solving problems in analytical chemistry. New York, Wiley, 1980. 512pp. $8.95. E. K. Turkdogan. Physical chemistry for high temperature technology. New York, Academic Press, 1980. 464 pp. $49,50. G. B. Fettweis. World coal resources. Amsterdam, Elsevier, 1979. 416 pp. U.S. $80.50 Dfl. 165.00 Canadian mines: 1979 perspective. Hull (Canada), Canadian Government Publishing Centre, 1980. C$2.40. Clarence Karr (ed.). Analytical methods for coal and coal products, Volume 3. New York, Academic Press, 1979. 656 pp. Charles B. Gill. Nonferrous extractive metallurgy. New York, Wiley, 1980. 500 pp. $30.00. M. Kuzvart and M. B6hmer. Prospecting and exploration for mineral deposits. Amsterdam, Elsevier, 1978. 432 pp. U.S. $68.25. Dfl.140.00. Martin A. Elliott (ed.). Chemistry of coal utilization, supplementary volume 2. New York, Wiley, 1980. 3000 pp. $150.00. M. Radetzki and S. Zorn. Financing mining projects in developing countries. Aedermannsdorf (Switzerland), Trans Tech. Publications, 1979. 200 pp. SFr. 48.00 (hard cover), SFr. 38.00 (soft cover). Charles G. Schofield. Homogenisation/blending systems design and control for minerals processing. Aedermannsdorf (Switzerland), Trans Tech Publications, 1980. 332 pp. SFr.98.00 (hard cover), SFr.48.00 (soft cover). A. V. Smoldyrer and Y. K. Safonov (translator: W. C. Cooley). Pipeline transport of concentrated slurries. Aedermannsdorf (Switzerland), Trans Tech Publications, 1979. 176 pp. SFI'. 115.00. V. M. Karasik (translator: W. C. Cooley). Slurry hydrotransport of minerals and tailings. Aedermannsdorf (Switzerland), Trans Tech Publications, 1979. 156 pp. SFr.1l5.00. S. P. Turchaninov (translator: W. C. Cooley). The life of hydrotransport pipelines. Aedermannsdorf (Switzerland), Trans Tech Publications, 1979. 158 pp. SFr.115.00. NIM reports Report 2037 The removal of contaminants from recycled water in a mineral-flotation plant. Report 2054 The determination, by X-ray spectrometry, of trace amounts of tin in titanium-bearing ores and concentrates and in siliceous materials. Report 2063 Aerosal deposition and carbon-rod atomization of gold. This report describes the determination, by flameless

Jan 1, 1980

By N. C. Gay

During the past two to three years, there have been some significant Improvements to the quality of the support systems being used on South African gold mines, and the Implementation of these new developments, together with more worker awareness has been instrumental in reducing rock-related accidents, particularly in deep mines. This paper provides guidelines to mine and group personnel on how to monitor the ongoing Implementation of new technologies and so ensure the benefits that will accrue in terms of mine safety and profitability. Particular attention is given to the establishment of auditing procedures that will enable management to assess the benefits obtained from new technologies, as well as providing Improved maintenance procedures and procedures for the optimum utilization of seismic data. The areas that receive most attention include support systems for stopes and tunnels, such as hydraulic props, backfill, and rockburst-resistant tunnel support; stope and regional support layouts; mine standards; and staffing of the rock-engineering department. The paper includes a draft audit form and a hypothetical example of an audit report

Jan 1, 1997