Search Documents

By G. Akdogan, C. Bergmann, C. J. Coetzee, Q. G. Reynolds, S. J. Baumgartner

Submerged arc furnaces (SAF) are used extensively in the production of ferrochrome, where charge material – consisting of mixtures of carbonaceous reductants, fluxes such as silica, and ore in the form of pellets – is fed through chutes into the vessel. The feed typically forms a thick bed or ‘burden’ of solid particulates above a bath of molten material below. This burden layer surrounds three electrodes, which are typically arranged in a triangular configuration in circular SAFs. A major challenge in the industry is the availability of sought-after reductants, volatile market conditions, and increasing electricity tariffs in South Africa. A good understanding of the physical properties of the raw materials in the charge is therefore of great value in order to best deal with the reductants available at any given time, and thereby maximising furnace throughput. This paper presents a study of the effects of different particle properties on particle flow behaviour relevant to SAF operations. Discrete element model (DEM) simulations were used to estimate the sensitivity of the particulate flow of beds of charge material to properties such as the coefficients of friction, particle shape and size, and others. The present study lays the groundwork for the development of full DEM models of the SAF that will greatly improve understanding of the flow of complex mixtures of solid particles in the submerged arc furnace, and how the relative physical properties of each component in the charge can influence electrical behaviour of the burden.

Sep 1, 2021

By J. T. Nel

The Kroll process is the traditional method of producing zirconium metal by reduction of zirconium tetrachloride with magnesium metal. This paper discusses the production of zirconium metal in a plasma reactor. Anhydrous low-hafnium ZrCl4 and Mg metal were fed continuously to a 30 kW non-transfer plasma reactor at a rate of 0.31 kg.h-1. Due to losses in the system the recovery of crude product was 77.5 %. After purification to remove unreacted feed material and MgCl2 by leaching, >98 % pure zirconium metal powder was obtained. The overall recovery of purified Zr was 74 %. The conversion efficiency of the process was 95 %.

Jan 1, 2012

By M. C. van Eeden, R. Vermeulen, K. B. Le Bron

This paper presents the lessons learnt during the transition from an open pit method to a sub-level open stoping method at the Koidu Limited kimberlite pipe. These learnings may assist other mines with planning, both from a practical implementation perspective (layout, charging up challenges), and a method for estimating potential dilution and stability challenges associated with the interaction between the surface and underground excavations. Predictive geotechnical stability modelling was successfully applied to highlight potential failure zones, which allowed modification and enhancement of the mining layouts and quantification of the potential dilution of the kimberlite from indicative instabilities.

Sep 1, 2025

By K. Eckert, A. E. Sommer, S. Heitkam

One highly relevant challenge in flotation is the recovery of fine particles. Due to their low inertia, these particles are mostly pushed aside by rising bubbles. Consequently, they typically exhibit low probability for bubble-particle collision and thus, a poor recovery rate. In this work, the trajectories of fine particles in the vicinity of rising bubbles were investigated. The measurements considered a chain of millimetric bubbles in a rectangular container filled with deionized water. The flow field near the bubbles was measured by tomographic particle image velocimetry (TPIV), employing fluorescent tracer particles of 33μm diameter. Subsequently, trajectories of larger particles and bubble-particle collision events are recorded with 4D particle tracking velocimetry using a high temporal and spatial resolution. The results reproduce the well-known collision of particles on the leading edge of a rising bubble. Additionally, collisions on the tailing edge were observed in cases with a low Stokes number. The TPIV results demonstrate, that the high turbulent kinetic energy in the bubble wake allows particles to divert from the fluid streamlines and collide with the tailing edge of the bubble. The tailing edge collision probability increases with the bubble Reynolds number and decreased particle inertia. Overall, the investigation shows that the collision of fine particles in the bubble wake should be considered for the development of further collision probability models. Furthermore, the importance of turbulence on the fine particle flotation was demonstrated. Keywords: 4D Particle tracking velocimetry (PTV), tomographic particle image velocimetry (TPIV), fine particle flotation, collision probability, bubble-particle interaction, wake induced collision

Jan 1, 2020

By S. Maluadzi, D. Rocchi, S. Luyckx, S. S. Potgieter-Vermaak, C. Machio, J. H. Potgieter

The aim of this work was to compare the corrosion behaviour of thermal spray WC ? based coatings before and after annealing. X-ray diffraction (XRD) was used to determine the phases present in the coatings at various stages. The corrosion resistance of the coatings was measured using electrochemical and immersion corrosion tests. The results obtained from electrochemical corrosion (quantified by corrosion current density) and immersion corrosion tests showed that annealing appears to decrease the corrosion resistance of the coatings. From the XRD results it was determined that the phases that corroded preferentially were cobalt (Co), eta (Co6W6C) and W2C. Keywords: Corrosion, thermal spray, coatings, hardmetals.

Jan 1, 2006

1. OPLEIDING IN INGENIEURSWERK VIR IN G ENIEURS- IN -OPLEID IN G 1.1 llegistrasie as Ingenieur-in-opleiding 'n Gegradueerde ingenieur wat in 'n eksamen geslaag het wat die Raad erkenl, is registreerpaar as 'n ingenieur-in-opleiding kragtens die Wet op Professionele Ingenieurs2. Aansoekvorms kan van die Registrateur verkry word. Mineral processing congress The XIIIth International Mineral Processing Congress is to be held in Warsaw from 4th to 9th June, 1979. Seeing that by products and co-products are becoming of increasing importance in mineral processing operations, the theme of the Congress is to be the 'Treatment of Raw Materials with Total Utilization of All Constituents'.

Jan 1, 1979

By G. A. Wiebols, N. G. W. Cook, N. C. Joughin

Discussion R. E. Rarnes (Member): The original concepts and the pioneering work now brought to the practical test stage by the Mining Research Laboratory team deserve our highest praise. The authors of this comprehensive paper rightly stress the urgency of establishing the extent to which the apparent potential can profitably be realised in practice. It is to be hoped that adequate funds will be made available by individual mining companies, the Chamber of Mines and manufacturers to attract the necessary staff and maintain the high rate of achievement of the last two years. From the Seventy-Eighth Annual Report of the Chamber of Mines and its members we see that, in 1967, with a Working Revenue of R759.8 million from gold and R54.6 million pit mouth coal sales and with profits from gold and uranium and pyrite of R307.9 million, only R1.9 million was spent by the Chamber on all forms of Research. It is considered unlikely that the associated mining companies and manufacturers exceeded this investment expenditure. Assuming a total of R4 million spent by the industry on Research and Development, this is less than half of 1 per cent of sales of gold and coal. This percentage, so low in comparison to North America and Europe, is no worse than that of Exploration expenditure which, in 1967, with South Africa's total mineral production of R1,287 million, was estimated to have been R6 million (Pretorius 1968). In a primary industry with ever present depletion of ore deposits and with cost escalation, expenditure on Exploration and on Research and Development is not a risky luxury but a tactical obligation. The potential rate of return on research expenditure into rock breaking is high. Stores consumed by gold and coal mines, members of the Chamber of Mines, totalled R316.2 million in 1967. Except for purchased power costing R42.2 million the highest cost group was explosives, drills and drill steel totalling R33.8 million or 10.7 per cent of the total stores consumed. In the paper under discussion it is claimed that the low 'effective stoping width' should greatly reduce the likelihood of rock falls or rock bursts to the extent that permanent support can be dispensed with. Insofar as this narrow cut is only 12 in. in advance of the working area which, with a 10 in. channel, is unlikely to be much reduced in width from that achieved by current methods, this claim is not readily understandable. Were it to have been based upon the regional support gained from packed waste it would have been more acceptable. Pre-developed stope drives may give serious trouble at depth and for this reason it is questioned whether a stoping area can avoid periodic sub-development blasting-the spoil and fumes from which will interfere with the rock flow and continuous mining of the rock-cutter. If, in the mining method proposed by the authors, stope drives are cut as small as possible (6 ft by 6 ft) then 25 per cent of the total tons handled (excluding resued waste) and 5 per cent of the gold will be blasted conventionally in the stope. At this stage one cannot envisage tunnelling machines economically or practically capable of such work. The various methods described by the authors and subsequent contributors for breaking waste are most interesting. It was noted that the 'bull wedge' and 'explosives' in Fig. 1 of the paper were no further from the ideal point 'A' than was 'cutting'. The writer considers that the bold and imaginative steps taken by the Mining Research Laboratory Team, the mining companies and the manufacturers concerned will eventually lead to a successful rock cutting machine with universal application largely independent of rock type. This may take many years. In the meantime other methods of improving productivity of saleable metal by rock breaking teams should be investigated even if such methods have local applications only. In 1955 the writer conducted tests with a wire saw similar to those used in quarries in the Northern Transvaal and elsewhere. Jeppestown shale, the immediate footwall of much of the East Rand gold field, was cut at the rate of 6 in. per hour using sand, water and a special endless rope driven by a low h.p. motor. A hypothesis on its application was submitted to the Office of the Government Mining Engineer in 1955 and to other mining institutions in 1966 after the writer returned to South Africa. By inference, rope sawing was classed as less promising than other methods tested in the Orange Free State Goldfields (Parker 1969). With highly resilicified hanging and footwall quartzites this was not surprising and confirmed the writers findings when testing hanging wall quartzite from the East Rand in 1955. The relatively uniform conditions, the low strength, hardness, and silica content of the Merensky Reef platinum deposits (Gray and von Bardeleben 1969) and in particular, the existence of overlying Merensky pyroxenite (Cousins 1964) make this and the East Rand attractive areas for larger scale testing of wire saws. It is envisaged that in suitable rock types the 5/8 in. slot would be advanced down dip or down a minor dip. In undisturbed areas 'faces' of up to 200 ft in length could be cut several feet in advance of breaking which could then consist of light blasting to the second free face or some of the methods now being tested for breaking waste in rock-cutting operations. A wire saw is an inexpensive and simple machine which, in some areas, could make significant and early gains in rock breaking efficiency as well as in ground and stoping width control.

Jan 5, 1968

By S. Soren, K. Deo Mehta, G. Jha

The paper aims to find a sustainable sintering process through cleaner means, in order to achieve the desired outputs with zero environmental impact. At present, sintering has no control over its environmental impacts. These impacts occur when fossil fuels such as coal and coke are used in metallurgical sintering. These fossil fuels are undoubtedly effective in their assigned reducing task, but simultaneously emit about 220 kg of GHGs (greenhouse gases) per tonne of sinter produced. The current attempt has focused on reducing these emission levels by switching from coke to a renewable fuel source such as biomass. Biomass is a cleaner fuel source with a significantly lower emission footprint compared to coke. In the experimental campaign, sawdust and wood-charcoal were used in substitution for coke. Experiments were designed in a progressing substitution to obtain the maximum substitution ability without compromising the sinter properties. Sawdust as raw biomass source optimally substituted 10% of coke. The substitution levels were remarkably higher (30%) for wood charcoal due to its low moisture and high calorific values. A fuel blend with 30% biomass and remaining coke succeeded in producing a sinter with acceptable quality indices. Sinters prepared with or without biomass contribution shared an identical phase transformation and microstructures. In order to to maintain consistency in the process, every effort was made to maintain all operational and process parameters identically, except for the fuelling framework. Keywords: Sintering, sustainable, biomass, GHGs, fuel substitution

Jan 1, 2020

By A. Marek

Reduced downtime and maximized availability of mining machines are the key factors in optimizing production rates. As technology moves industry towards an age of ?intelligent machines? it sets the foundation for change in mining equipment design, functionality, and maintenance. Recent mining machine designs are integrating more and more electronic components into the core functionality of individual piece of equipment due to regulatory and legislative requirements, such as TIER rating, as well as from a safety aspect such as personal detection systems. This paper describes the use of existing on-board electronic equipment to increase machine availability through automated maintenance planning and diagnostic fault-finding capability. The automated maintenance planning takes place on the machine itself in order to be independent of the mine?s infrastructure, while the diagnostic capabilities allow for reduced downtime. The paper also presents a concept to transfer operational data to surface to be able to optimize planning of maintenance and to reduce downtime. Case studies are presented where such systems have been commissioned and are currently in operation, the possibilities of this technology application for the future are examined.

Jan 1, 2012

By L. Forbes, G. Forbes, J. Wang

Bubble size measurement is a vital part of flotation system analysis and diagnostics. Over the years, a great many different bubble size analysis tools have been developed. However, all of them rely on ex-situ measurement and in-pulp sampling techniques. This paper evaluates the Mettler Toledo ParticleView™ Measurement probe as a novel method for in-situ bubble size measurement. This device is then compared to the conventional Anglo Platinum Bubble Sizer (StoneThree). It was found that the in-situ bubble size analysis technology appears to be a more user-friendly and reliable option for determining bubble size in flotation. However, the current instrument design is not suited to industrial applications. Keywords: Bubble size measurement, bubble coalescence, PVM probe

Jan 1, 2020

Primary roof support represents the first line of defence against rockrelated falls of ground in underground mines, and improper utilization or misunderstanding of the applicability and behaviour of primary support can be costly from a safety standpoint. This is a major concern for underground mines, as roof support is the single most costly expense from a mining operational perspective. This is further backed by the evidence that, in the USA, hundreds of injuries and fatalities still occur each year because of rib, roof, and massive roof falls. Additionally, the fully-grouted passive rebar, fully-grouted tension rebar, and resin-assisted mechanical anchor bolts, which constitute a large portion (89%) of the 68 million bolts installed each year in underground mines in the USA can vary in cost quite dramatically. To mitigate this concern a study was conducted in 2010 by the National Institute of Occupational Safety and Health, in conjunction with Southern Illinois University of Carbondale, to assess the performance of primary roofbolts in underground coal mines for improved safety and cost. This was accomplished using underground roofbolt monitoring solutions, field data, and numerical modelling to better understand the quasi-static behaviour of underground coal mine roofs and the response behaviour of the bolts. In particular, over 170 instrumented extensometers, closure meters, shear meters, fully-grouted passive rebar, fully-grouted tension rebar, and resin-assisted mechanical roofbolts were installed at three coal mines across the USA. Of these three mines, two used the room and pillar extraction method and the other used the longwall extraction method. There was no evidence to indicate a difference in performance of the active primary roofbolts compared with the passive primary roofbolts. Additionally, in the initial loading phase, the active bolts showed no difference in loading, indicating that tension bleed-off is of more of a concern than originally thought. Lastly, for the initial computer modelling studies, challenges still remain in obtaining a good match to the in situ bolt measurements and replicating the discontinuous roof rock and in situ bolt behaviour over time.

Jan 1, 2014

By H. Lieberwirth, M. Klichowicz

The comminution at grain size level for the liberation of valuable minerals usually requires the highest size-specific energy. Therefore, the full understanding of the comminution process at this level is essential. Models based on the Discrete Element Method (DEM) could be a helpful tool for this purpose. In those, the mineral microstructure, which has a dominant influence on the fracture behaviour, can be described in great detail. One major concern, however, is the missing representativeness of simulated models. In this study, a method to overcome this limitation is presented. The authors show how a realistic microstructure can be implemented into a particle bed comminution simulation using a two-dimensional Bonded Particle Model (BPM). The improved algorithm based modelling approach is exemplarily compared to an equivalent real experiment. Thereby, the focus is set on the analysis of the interfacial breakage and the capability of the simulation to reproduce the experimental results. The comparison of the results shows that simulations at grain size level allow a more detailed evaluation of the fracturing behaviour. This is of special interest as the aim of comminution in mineral processing is not only the size reduction of coarse particles, but an efficient liberation of the valuable components. Hence, simulations with automatically generated real mineral microstructures will help to further improve the efficiency of ore processing. Keywords: Discrete Element Method, grain modelling, particle bed comminution, realistic synthetic

Jan 1, 2020

By C. Bergmann, V. Ross

The concept of underground ore processing, in which valuable ore and waste are separated at a coarse particle size to improve the economics of operations and minimise the environmental impact, seems attractive from a sustainability perspective. Perceived benefits of such an operation include energy and cost savings due to a reduced hoisting load, a reduced footprint of surface operations, and using material for backfill that has not been contaminated by process chemicals. Progress in the South African mining industry in this area has however been below expectation, and opportunities for underground processing in deep, narrow reef operations were therefore explored by an Excel-based simulation with sensor-based sorting (SBS) as concentration technology. Various PGM mining scenarios incorporating factors such as the mining rate, depth of operation, and effects of dilution and particle size on the metallurgical efficiency, were compared. Whilst these initial results can be regarded as indicative only, they have shown that the economics of such an operation are driven by selective mining at significantly higher rates than achievable with conventional methods. Also, the cost of preparing, conveying and placing rock backfill will need to be lower than that of hoisting waste and depositing it on a surface dump. Another aspect to be addressed is whether ore sorting machines would be able to operate under harsh conditions underground and what provision would need to be made to ensure their efficient operation. Further investigations should focus on refining costs, incorporating environmental considerations in the modelling of economics and sustainability, and compare greenfields with brownfield scenarios. Keywords: Ore sorting, hoisting, backfill, mining rate, economics simulation

Jan 1, 2020

By S. Gqebe, A. Lewis, M. Rodriguez-Pascual

"Gravitational sedimentation of suspensions in various precipitation processes is hindered by colloidal stability. This is due to the high surface charge of the suspension and results in strong attraction/interaction between the ions on the particle surface and counter-ions in solution. Moreover, this strong interaction results in a charge build-up that renders the suspension stable. In order to induce gravitational sedimentation of these particles, a redistribution of ions close to the particle surface is required. We therefore sought to redistribute ions close to the particle surface by applying a magnetic field. This results in the reduction of interparticle electrostatic repulsive forces and a subsequent increase in the zeta potential of a suspension. For the purpose of this study, a copper sulphide suspension was used. Copper sulphide particles were exposed to a range of field strengths for set exposure times and their zeta potential was measured before and after exposure. All particles had an initial zeta potential value equal to or less than –40 mV prior to magnetic field exposure. A significant increase in zeta potential was observed, with values reaching a maximum of –16.5 mV when exposed to a 2 T field strength for 40 minutes. This is due to Lorentz ion shifts resulting from the Lorentz force exerted by the magnetic field on the particle surface. IntroductionMetal sulphide precipitation is a process for treating industrial waste streams with high residual concentration of mixed metal ions and acid mine drainage. This process has been reported to achieve higher metal removal compared with the industrially prevalent lime precipitation, due to the sparingly soluble nature of the metal sulphide precipitates formed. However, precipitation is governed by high levels of supersaturation which favour the formation of fine particles (Lewis, 2010). Consequently, some of the metal sulphide fines formed exhibit slow settling dynamics and thus tend to remain suspended in solution."

Jan 1, 2016

By A. Cambitsis

We show that the prioritization of business improvement and performance management decisions may be significantly improved by taking into account the systemic effects of changes made in a single process area. To do so we build a model of a mining value chain, taking into account consequential downtime that arises from downstream and upstream starvation and choking effects of each activity. Introducing the concept of internal capacity, this approach yields insight into the relative importance of key metrics such as loading and hauling rates. We suggest that a holistic view of this type should be a core component of business improvement and performance management decisions.

Jan 1, 2012

By L. J. Park, A. D. Thomas

Gladstone Pacific Nickel Limited (GPNL) is proposing to develop the Marlborough nickel deposit in central Queensland and the Yarwun Refinery in Gladstone, Australia. The project proposes to connect the two sites with a DN 500, single pump station slurry pipeline, transporting up to 4 Mtpa of nickel laterite ore as slurry 180 km from Marlborough to Gladstone. Slurry viscosity is a key parameter influencing pipeline design. Not only is the slurry viscosity relatively high, requiring pumping at low concentrations, around 30% by weight, but the viscosity (yield stress and plastic viscosity) increases with shearing or agitation. It is argued that the viscosity changes can be analysed in terms of total energy input, including energy input during grinding. The slurry viscosity is therefore expected to increase along the pipeline and the pumping concentration must be low enough such that the increase in yield stress does not cause transition to laminar flow towards the end of the pipeline. The base viscosity of two ore types is determined using a rotational viscometer for minus 212 micron slurries. Viscosity variations with ore particle sizes of d99 212, 425 and 600microns are investigated. For each of these particle sizes the expected increase in viscosity during pipeline transport is simulated on a laboratory scale by agitation with a turbine mixer in a baffled container to give the same equivalent unit energy input as will occur in the pipeline. Tests were also conducted on the d99425 micron slurry in a 2.7 metre diameter DN 200Wheelstand, rotated for the 23 hour transit time and at a similar relative velocity as in the pipeline. Based on the Wheel stand test results the yield stress is expected to increase by a factor of 3.1during pipeline transit. The preliminary design allows for a reduced pumping concentration to accommodate this increase in yield stress towards the end of the pipeline.

Jan 1, 2007

Since 2001, the Hybrid Stress Blast Model (HSBM) project members have developed a software suite to model the complete blasting process from non-ideal detonation to muck pile formation. To preserve the physics and improve solution time, the breakage engine uses a combination of analytical models and 2D axisym-metric finite differences to model near-field crushing, coupled to 3D discrete lattice fracturing and distinct element numerical methods to model throw and muck pile development. The model has been validated by comparison with laboratory and field tests in kimberlite. Multiple blasthole simulations are used to demonstrate how changes to blasting parameters can influence downstream efficiencies. Case studies of wall control blasting show that the presplit design must balance the two opposing effects of increased damage with increased charge and decreasing attenuation of the seismic waves with decreasing charge. Modelling of decoupled explosives needs further development. Reducing the charge towards the back of the trim blast results in a much more significant decrease in back damage than altering the timing. The model demonstrates how separation along the weaker planes in a jointed rock can coarsen the fragmentation, leading to inefficient beneficiation, and extends the damage to a distance of at least twice the burden behind from the blasthole, severely compromising the wall stability.

Jan 1, 2012

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

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

Jan 1, 2020

"Sampling error and bias, especially the Increment Preparation Error (IPE), are introduced when the tool allocated to do the job fails to extract a representative sample. This is the case with chip sampling; the tool can only extract haphazard shapes of loose or fractured material and not always from within the demarcated sample area. Increment Extraction Error (IEE) and Increment Delimitation Error (IDE) could be severe, but are found to be relatively unbiased. The uncontrolled action of the sampler in discarding excess sample material after sample collection has a significant impact on the error and bias introduced with each and every extraction. A new type of bias, referred to as the ‘waste discard bias’, arises when samplers select what portion of the excess sample material to discard at the sample site. Material visually identified as waste is discarded in preference to mineralized broken ore if there is an excess of sample material. This results in a considerable error in the analytical results. The bias is proportional to the reef-waste ratio in the demarcated sample. IntroductionTwo types of ‘sampling’ are distinguished, namely sampling of particulate materials (broken ores) and sampling of solid, unbroken in situ mineralized reef. This study considers only chip- or face-sampling of in situ, goldbearing, carbon-rich conglomerates typical of the Upper Witwatersrand Supergroup and examines where components of sampling error and bias, clearly specified in the Theory of Sampling, may arise during the practice of ‘face sampling’. Many millions of face samples have been extracted from Witwatersrand-type mines using a hammer and chisel, and detailed descriptions (standard operating procedures) of how the samples should be taken have been developed by many mining companies. There is, however, no taxonomy or nomenclature for managing or reporting the different types of errors associated with chip sampling. The Theory of Sampling compiled by Pierre Gy in the early 1950s provides, comprehensive nomenclature of sampling errors that is applied to particulate sampling of ore in a lot, a stockpile, or a moving stream on a conveyor belt. The taxonomy and characteristics of sampling errors, grouped according to the sources from which they arise, and identified by Gy (1973, 1979, 1982, 1992, 1995, and 1998) are shown in Figure 1. This classification of errors is used extensively in regard to the sampling of particulate materials in the mining and minerals industry, but not in regard to chip sampling. A relatively small mass (hundreds of grams) of representative particulate material for estimating the average grade of a much larger mass (thousands of tons – the ‘lot’ in the Theory of Sampling) is extracted by the chipping or cutting of a representative rock ‘sample’ from the stope face."

Jan 1, 2016

This paper sets out to consider a specific type of corrosion protection system, which is referred to as a Duplex Coating system. The dictionary describes a duplex system as consisting of two elements or a “twofold” composition. The duplex system described in this presentation is such a two-part corrosion protection coating, viz, hot dip galvanizing as the firm base or primer, followed by a top paint system designed to combat severe corrosive environmental conditions encountered in nature. In principle, the duplex system is a cost effective and balanced, designed coating that is suited to the environmental conditions and service life requirements.

Jan 1, 2009