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By L Thompson, R C. West, T S. Kho

In 1978, the Outotec direct to blister flash (DBF) smelting process was commercialized with the commissioning of the Glogow 2 smelting facility in Poland. Since then four further DBF facilities have been constructed, two at Olympic Dam, one in Zambia and most recently one at Glogow 1 in Poland. The DBF smelting process differs considerably from conventional smelting process in both chemistry and unit operations, presenting opportunities for flowsheet capital and operating cost savings particularly when the concentrate copper grade is high. WorleyParsons has amassed considerable expertise in the Direct to Blister process and in this paper the process is compared to the modern two stage Double Flash process. The processes are modeled, and the key operating parameters, consumables and production metrics are directly compared. Subsequent flowsheets, key equipment lists and capital costs are also presented for comparison and discussion. The results show the range of concentrates which are most economically treated by the DBF process relative to those best treated in conventional processes along with those concentrates which could be treated by either process. INTRODUCTION The Outotec Direct to Blister (DBF) process was developed and installed at Glogow in 1978 (Czernecki et al., 2006). Currently there are a total of five DBFs built on three sites: Glogow No.2, Olympic Dam No.1, Olympic Dam No.2, KCM Zambia and Glogow No.1, being the most recently constructed. The DBF process was the first flash furnace process to produce blister copper and paved the way for the subsequent development of the flash converter and other continuous converting processes. Today four flash converters are in operation taking the total number of flash furnaces producing blister copper to eight. In all DBF operations it is the unique ore and concentrate composition which made selection of the DBF process the most attractive. In all cases, the concentrate is relatively high in copper but low in iron because chalcopyrite is not the major constituent. When considering smelting options for high copper, low iron concentrates a key question is then often asked, “At what point does it become economic to switch from two stage smelting and converting process to the DBF process?”

Jan 1, 2019

By A. Ghahreman

Activated carbon is proven to be able to catalyze arsenic oxidation in aqueous solution under acidic conditions. A commercially available granular coconut shell based activated carbon (AC) has been evaluated for catalysis of arsenic oxidation in this study. The rapid small-scale column test (RSSCT) has been developed to simulate and predict the performance of a carbon-based arsenic treatment system in a pilot scale reactor. Effects of residence time, aeration rate, and initial arsenic concentration in the influent solution on the AC catalysis of arsenic oxidation under dynamic and continuous conditions were studied by manipulating these parameters during RSSCTs. The effectiveness of the AC on arsenic oxidation was examined over the course of constant diffusivity based RSSCT operation. Residence time and initial arsenite concentration are proven to be the most effective impacting parameters on the arsenic oxidation process. For the 218 min residence time, the highest steady-state arsenic oxidation efficiency achieved was 98% with 1 g/L As(III) being treated at pH=1 under 0.05 L/min oxygen aeration. In a long-running RSSCT, the oxidation efficiency did not seem to deteriorate over a course of 666 hours operation, corresponding to 13986 mL total influent throughput volume. INTRODUCTION Arsenic is toxic to both animals and plants and inorganic arsenicals are proven carcinogens in humans. The increased extraction of low grade and complex mineral resources has introduced high ratios of arsenic into metallurgical processes. Discharge of arsenic by acid mine drainage resulting from mining activities has added intensive pressure on the need for proper treatment (Lawrence & Higgs, 1999). Since trivalent arsenite is more toxic and has lower affinity to solid surfaces for adsorption, many treatment systems initiate with an oxidation step to convert arsenite to arsenate and reach the ultimate immobilization of arsenic by the following precipitation of arsenate (Nazari, Radzinski, & Ghahreman, 2016). Scorodite precipitation has been studied extensively as a means of arsenic immobilization due to its high stability and negligible potential of releasing arsenic (Filippou & Demopoulos, 1997). As a stable ferric arsenate mineral, crystalline scorodite can contain up to 30 wt% arsenic (Paktunc, Dutrizac, & Gertsman, 2008). Arsenic must be in its pentavalent oxidation state in order for scorodite to be precipitated via oxidizing ferrous ions (Clancy, Hayes, & Raskin, 2013).

Jan 1, 2019

By Shinji Shirakawa

The gold wire bonding technology is widely used for electrically connecting aluminum pads on IC devices to external terminal of semiconductor. In 1960?s, the tensile strength of gold bonding wire was about 100 MPa only. However, recently the wire with 300 MPa in strength has been developed. Since the gold bonding wire was started to use for IC package in early 1960?, the many types of gold bonding wire has been developing continuously in order to meet market?s needs, such as high density, small size and thin type of IC packages. Moreover, electronic equipments were used in automobile applications and also demanded good reliability under severe temperature environment. Thus Au-Pd alloy wire has been introduced instead of the wire with 4N(99.99wt%) purity gold to provide excellent reliability in Au-Al bond interface. The phenomena at Au-Al interface in the high temperature storage have been already explained by several studies as follows. There are five phases of inter metallic compound (IMC) between gold and aluminum. Just after bond gold ball on aluminum pad, Au5Al2 phase was formed and occupied almost all of IMC area. During high temperature storage test, Au5Al2 phase transformed to Au4Al phase, then this phase was corroded by Bromide (Br) ion that was isolated from molding resin. Thus the reliability between Au and Al degraded. In case of Au-Pd alloy wire, the concentrated palladium phase (Au-Pd-Al) was formed at the interface between Au alloy ball and Al pad. The Au-Pd-Al phase prevented from transforming between Au and Al, therefore Au5Al2 phase was hard to transform to Au4Al phase. Consequently the reliability at the interface between Au alloy ball and Al pad was less degradation. However, in recent study using several advanced analysis technique, Au4Al phase was found at the interface between Au alloy ball and Al pad same as the case of conventional gold wire (4N purity gold bonding wire). It was suggested that the formation of concentrated palladium phase (Au-Pd-Al) related the excellent reliability at ball bonding process.

Oct 1, 2003

By J. Jackman

North America has been aggressively pursuing approaches to improve the fuel efficiency of vehicles, and to develop alternatives to petroleum-based fuels used in automotive applications, for over ten years, Increasing energy demand due to emerging economies, coupled with probable peaking of conventional petroleum production in the coming decades are increasing the need to reduce dependence on petroleum-based fuels for transportation, Vehicle lightweighting is seen as an important strategy to improve fuel efficiency of conventional as well as highly innovative vehicles, Magnesium has recently emerged as a serious candidate for lightweighting, as a result of lower global prices, Automotive vehicles produced in North America currently use more Mg than vehicles produced elsewhere in the world, but the amounts per vehicle are very small in comparison to other materials such as steel, aluminum and plastics, The reasons, besides price, are primarily a less-developed state of technology for Mg in automotive transportation applications and lack of familiarity by the vehicle manufacturers with the material, This paper reviews the major government-funded research programs in the USA and Canada that are dedicated to advancing the state of Mg technology for automotive applications, It provides examples of research in the areas of high-pressure and other types of castings, corrosion solutions, sheet development and other wrought applications.

Jan 1, 2006

By V. Ogarlaci

Over 90% of the Romania's lignite reserve is located in the region of Oltenia, which is why this area is given special attention in the country's coal resources. Because the lignite deposit of Oltenia is comprised of 1-8 exploitable coal layers, their capitalizing calls for urgent arrangements to ensure rational exploitation under conditions of total safety, minimum losses and efficiency. The technology used the coal pits of North-Western Oltenia is the technology of excavation, transport and dumping in a continuous flow by using the complexes of excavation, transport and high-capacity dumping. The theme of this paper is of particular importance because the rhythmic operation in complete safety, is necessary both for sizing and keeping within the bounds of acceptable values, throughout the process of excavation of the geometric elements of the coal faces, marked by: the height of benches, slope angle and width of berms. Geometric dimensions of the benches of the open pits, the height of benches, slope angle and width of berms shall be calculated and shall be based on: the massif structure that forms the benches; physical-mechanical characteristics of rocks from the bench; working conditions, characterized mainly by mining and extraction methods applied; functional parameters of the mechanical equipment used to perform various operations on the coal face etc. For this study it was necessary a broad field for task tracking, measurement, research and design elements of the coal face, for land survey and a desk activity by: processing of topographic data, laboratory analyses on physical and mechanical properties of rocks and numerous specialized studies. In the final part, we bring some contributions to elucidating the issues of special importance for the lignite coal pits of Oltenia, coming up with data, graphics, formulas, solutions and concrete dimensioning of coal faces in terms of using technology in a continuous flow.

Aug 1, 2013

By A. E. Wraith, J. Protheroe Jones, P. J. Mackey

INTRODUCTION When Victoria became queen in 1837, that technical wonder of the 19th century—electricity— had progressed from being an exciting physical curiosity and was now a field of intense scientific investigation, invention and application. Its role in electrochemistry had been brilliantly quantified by Faraday in 1833–1834, and his earlier discoveries in electro-magnetism were to lay the foundations of electricity generation and the electric motor. In this age of electrical experiment, silver electro-plating emerged as a popular decorative art, at first using batteries to provide the deposition current, superseded by dynamos in the early 1840s. The decorative chemical and electroplating of precious metals was largely pioneered in England by the firm of G.R. Elkington and Co., founded in Birmingham by George Richards Elkington (1801–1865) in 1832, and protected by a series of patents which helped the company establish a leading position in the new field of ‘electrometallurgy’. In the same decade, the technique of electrotyping emerged, the first application of electro- forming by electrolytic deposition. Simultaneously invented by Spenser in England and Jakobi in Russia, but generally claimed for Jakobi, electrotyping involved plating a thick copper layer on to an electrically conducting mould wall embossed or incised with a pattern or profile which would consequently be replicated on the copper deposit—essentially a method of casting by electro-deposition with the mould wall as cathode. Woolrich’s invention of the low voltage magneto-dynamo in 1842 eliminated the need for batteries as a continuous source of deposition power, opening up the possibility of making more massive electroplated deposits, and by the mid-point of Victoria’s reign in 1869, the work of Wilde, Wheatstone and Siemens had produced the self-excited electro-dynamo, capable of higher voltages and yet greater deposition power. In this early Victorian period copper was extracted and refined by methods which had developed step-by-step over many decades. Only relatively rich copper ores containing more than, say, 6% Cu were economically useful, and the final copper product was far from pure. Copper production in Britain was located principally in the Swansea area of South Wales, based upon the ‘Welsh process’ of reverberatory batch smelting and refining, using locally mined coal and ore imported from Cornwall and elsewhere. Silver was an important by-product. Much of the output was exported and South Wales remained a principal supplier to the world copper market until the 1890s. It was here at Pembrey, a few miles west of Llanelli, that a new primary copper smelter was stablished in 1849 under the name Mason and Elkington, arguably to supply the Elkington company’s market for electrotype products.

Jan 1, 2019

Mining companies around the globe have long struggled with the need to ensure that earth moving equipment is designed to be operated and maintained under all site conditions without causing harm to people. Incident and accident data from a range of sources clearly identify mining equipment related issues as major causal factors. One Australian source, the NSW Department of Primary Industries? International Mining Fatality Database Project Report (2008) noted that ?Approximately 77% of mining accidents resulting in a fatality have? involved equipment?. The largest number of fatalities were associated with trucks; the next with LHDs. Many of the technical advances in equipment design over the past few decades have not been matched by advances in the human factors design of mining equipment, resulting in a ?design vacuum? that must be filled prior to commissioning new equipment. This ?design vacuum? is generally filled by local dealers. They retrofit equipment according to customer requirements to mitigate risks that have not been designed out by the Original Equipment Manufacturer (OEM). Mining companies have been frustrated by lost time and additional costs associated with this need to retrofit ex-factory designs. Some companies have attempted to address the problem by negotiating company or site-wide ?solutions? to equipment designs, but this has not simplified or clarified the issue from the point of view of the equipment manufacturers. A number of mining companies operating in Australia first discussed the concept of a joint customer approach to improve the Human Factors design of earth moving equipment at the factory level in 2004. They agreed that a new approach to engaging with OEMs was needed; one that would define the ?Problem?, in other words, the basis of the risks, rather than dictate the ?Solution?. The Earth Moving Equipment Safety Round Table (EMESRT) was formally established in 2006 by six global mining companies to establish a process of engagement between Original Equipment Manufacturers (OEMs) and mining customers.

May 1, 2009

By A. Vasebi, É. Poulin, A. Desbiens, D. Hodouin

Maximizing benefits generated by separation plants in the mineral processing industry is of prime importance. To achieve this goal, observers and controllers are both key tools playing a crucial role for economic optimization. Although these methods have been widely discussed in the literature and that numerous applications have been reported, coupling the different algorithms raises practical challenges. The economic function definition, the selection of the real-time optimization structure, the elaboration of observer and controller models, the controller development, and the tuning of stochastic and deterministic parameters strongly influence economic performances. The objective of the paper is to discuss the major difficulties related to the implementation of a real-time optimization system and highlight the benefits of linking data reconciliation and model predictive control for a simulated flotation plant. A systematic topdown approach is used to go through the main design phases and to comment on the different options available for the development of the optimization structure. An internal model predictive controller coupled with a stationary observer is applied for the direct optimization of a three-stage flotation plant simulator based on a phenomenological model. The results show performance improvements in terms of increased revenues brought by reduced grade variability and collector consumption. The discussion also proposes alternative avenues that could be taken to achieve comparable improvements. Finally, since the limited simulated case-study cannot provide a complete understanding of the benefits brought by a data reconciliation observer, recommendations for industrial applications, which are more complex, are provided to promote effective implementations.

Jan 1, 2016

By P. Mattar

The geotechnical importance of studying fluid flow through porous media and soils in particular, becomes evident when dealing with groundwater movement in surficial geomaterials that can be initiated by hydraulic gradients that develop during construction activity, groundwater extraction, impounding of reservoirs and groundwater recharge during adverse climatic events. In a geotechnical context, rocks are regarded as virtually impermeable materials, with comparatively greater resistance to flow of water through their pore structure. The importance of the permeability of rocks comes to the forefront when deep geologic formations are used in geoenvironmental activities for disposal of hazardous and toxic materials. The permeability of the rocks encountered is of critical importance to these geoenvironmental activities since the movement or transport of the hazardous materials during their eventual release will be largely governed by the permeability characteristics of the geologic formation. The estimation of the permeability characteristic of geologic formations is a non-trivial exercise since the measure of permeability can be influenced by the scale at which the measurement is made. Regional-scale and borehole-scale estimates of the permeability can be greatly influenced by the inhomogeneities, including fractures, fissures, solution channels and other anomalies that are present in naturally occurring geologic media. These anomalies are considered to be site specific and can only be determined in a reliable fashion by either conducting tests at the appropriate scale or in the regional-scale through inverse analysis of tracer movement patterns in rock masses. The estimation of the permeability of intact units of a geologic medium has important geoenvironmental applications in connection with storage of wastes since the units in which repositories will be located should be sparsely fractured and the sealing of the fractures and fissures are a prerequisite to developing an efficient solution for storage. The intact permeability of geomaterials is therefore regarded as an important property that influences efficiency and reliability of geoenvironmental solutions for deep geologic disposal. The permeability of geomaterials such as concrete and cementitious grouts are also important to many geoenvironmental and infrastructure applications where durability of structural materials in general and cements used for sealing deep boreholes and other access shafts employed in waste management endeavours is influenced by the permeability characteristics of these materials

May 1, 2009

By Donald S. Cameron

By dispersing gold in high surface area form supported on metal oxides, its inert character can be transformed to make economical, effective catalysts. Gold has already been demonstrated in a number of fuel cell applications such as gas phase catalysts, electro-catalysts, and electrical connectors. In this paper, the various types of fuel cell systems are reviewed, and several opportunities for gold identified. Low temperature fuel cells, including alkaline and solid polymer electrolyte types rely on high surface area platinum group metal catalysts which are highly susceptible to poisoning by low concentrations of carbon monoxide in the fuel supply. Hydrogen is frequently obtained by steam reforming hydrocarbons, followed by the water gas shift (WGS) reaction. A promising initial use for supported gold catalysts is in catalysing this WGS reaction. Research has shown that gold supported on iron oxide (Au/a-Fe2O3 ) WGS catalysts are more active than the current commercial copper oxide / zinc oxide catalysts, and effective at temperatures as low as 120oC. Products from reformer/ water gas shift reactors can be further purified by removing traces of carbon monoxide. If a small proportion of oxygen is introduced into the fuel gas stream, carbon monoxide can be preferentially oxidized to carbon dioxide even in the presence of hydrogen. Gold nanoparticle catalysts on iron oxide support (Au/a-Fe2O3 ) have exhibited higher activity than commercially available platinum on alumina (Pt/?- Al2O3 ) preferential oxidation catalysts. The low temperature of this reaction may make it feasible to incorporate these catalysts within the fuel cell itself. Proton exchange fuel cells provide several possible applications for catalytically active gold and its alloys. Carbon supported platinum group metals would benefit greatly from improved electrical conductivity if gold replaced some or all of the carbon support material. As electrode current densities are raised, electrical resistance constitutes an increasing proportion of voltage losses within the fuel cell. Dramatic reductions in cell stack voltage losses have already been demonstrated by reducing inter-cell contact resistance using gold plating. The low temperature oxidation properties of gold catalysts have been investigated in controlling gaseous emissions from direct methanol fuel cells, and gold also provides essential catalysis in building direct borohydride oxidation fuel cells. The prospect of a range of other applications for gold in fuel cells to contribute useful improvements in corrosion resistance and conductivity is assessed. Globally, fuel cells have been developed for a wide range of applications including stationary generators, cars and buses, industrial vehicles and small portable power supplies, each of which represents a substantial market. Hence there are likely to be many and varied opportunities for gold catalysts to contribute to the performance and economics of the systems being commercialized.

Oct 1, 2003

By B. McFadzean, J. Taguta

In order to recover minerals by flotation, the sub-processes of collector adsorption onto the valuable minerals followed by bubble-particle attachment should occur efficiently. This paper investigates both of these sub-processes for various thiol collectors and their mixtures onto base metal sulfide minerals. The aim of the work was to investigate whether there is a correlation between the strength of the collector interaction with the mineral and the subsequent bubble-particle attachment. The collector-mineral affinity was measured experimentally using an isothermal titration calorimeter in order to determine the molar enthalpy of adsorption for each collector-mineral system. The bubble-particle attachment was measured using a microflotation device which essentially determines the hydrophobicity of the mineral. Sodium ethyl xanthate (SEX) and sodium diethyl dithiocarbamate (DTC) and mixtures thereof were used as collectors with either single minerals or binary mixtures of pyrite and chalcopyrite, respectively. The adsorption enthalpies of the collectors were interpreted with reference to the chemical structure of the collector molecule and showed that the greater the positive inductive effect of the collector, which may be qualitatively related to their pKa, the greater their affinity for the mineral surface. In the microflotation studies, recoveries were strongly related to the alkyl chain length but there was no correlation between the enthalpies of adsorption and the flotation recoveries. When mixtures of collectors were used there was clear evidence of synergistic effects and in the case of DTC/xanthate mixtures it is possible that this synergism is related to a DTC promoted oxidation of xanthate to dixanthogen. When mixtures of pyrite and chalcopyrite were used the flotation recovery and enthalpy of adsorption of SEX onto the individual pyrite particles in the mixture increased substantially compared to the case of pyrite alone. Mechanisms are proposed to interpret these important observations.

Jan 1, 2016

By A. Probst, J. A. Finch

"Solids concentration (% solids) profiles and the clear liquid/slurry interface level (mudline) were determined from conductivity measurements in thickeners at Falconbridge' s Strathcona mill (Ni concentrate and non-mag thickeners) and Kidd Creek Division (Cu, Zn concentrates and final tails in the concentrator and thickeners in the Zn plant).The conductivity measurement system consisted of a probe 1.5 m in length with 24 electrode cells, a 24-channel relay, a conductivity meter and a computer. A conductivity profile is collected which locates the mud-line by the sharp change in conductivity. The conductivity measurements are readily converted to solids concentration profiles without need for calibration.The results from the conductivity measurements were compared with those from pressure profiles and direct measurements on local samples obtained using a modified Noranda sampler.It is concluded that the conductivity technique is applicable to locate the mud-line and to estimate the solids concentration profiles in thickeners. This on-line information could improve the operational efficiency of industrial thickeners.INTRODUCTIONAn automated, on-line technique for detecting the clear liquid/slurry interface (or mudline) and the variation in solids concentration with depth would enhance thickener operation and control. In some processes such enhanced control offers significant benefits. For example, in hydrometallurgical operations solid/liquid separation is often the process limiting step. Water treatment plants are increasingly expected to operate remotely and reliable sensing is vital.Current attempts to detect the mud-line include reflection of some signal (e.g. sonar), floats (Dahlstrom, 1985) and measurement of pressure (Rosenblum, 1991), and in one case, natural radioactivity of the solids (Johnston and Simic, 1991). A recent commercial development uses reflection from a vertical array of optical transmitters/sensors, which also gives local solids concentration (BTG Inc., 1991)."

Jan 1, 1993

By Jose A. Jimenez

"Mining operations generate an enormous amount of data that is difficult to organize, analyze and act on. These data require an extremely broad range of experts to investigate and manage the cross-disciplinary information. The data collects in paper files, diverse databases, historians, stand-alone applications, and excel files. This collection of sources represents everything from monthly, weekly, or daily inputs to real-time feeds or sporadic unscheduled entries. With the operational complexities ever increasing and fewer engineers per mine, an efficient operation is becoming more and more challenging. Engineers are typically burdened with data collection, clean up, and administrative efforts leaving very limited time for engineering assessment and/or optimization analysis. Often optimization becomes limited to the analysis of equipment uptime through existing field automation systems. A great portion of the field data is tucked away in historians seldom reaching those engineers who might leverage the data. Few mine operators have the time or budget to re-architect their operations data collection or management practice, so solutions must enable improvements without requiring expensive or time-consuming implementation. This presentation highlights examples where the aforementioned challenges are addressed using a solution framework designed to enable: 1) data integration and connectivity, 2) monitoring and opportunity recognition, and 3) engineering workflow automation. The initiative extends the concepts and success proven in the automation market segment to all disciplines across the mine operations. INTRODUCTIONThe mining industry by its very nature spends a great deal of its capital on equipment maintenance and replacement. In addition, periodic shutdowns due to equipment failure are typically very costly in terms of interrupted operations. Keeping mining equipment running at peak performance and avoiding costly shutdowns can make a huge difference in the overall return from mining operations. Today, information can be make available that can go a long way towards spotting equipment issues and permitting timely intervention to avoid costly unplanned shutdowns. That said, gathering all of the information from numerous points on many different pieces of equipment necessary to enhance overall equipment effectiveness presents its own daunting issues."

Jan 1, 2016

By Ted Nuorivaara

The use of polymer-surfactant mixtures as foam stabilization agents is a topic that has drawn the attention of several fields but has so far not be thoroughly studied in the context of mineral froth flotation. The present work showcases a study on the impact on flotation performance of cellulose surfactant derivatives and their mixtures with commercial frothers. Bubble size and foam property measurements were run in a two-phase system along with laboratory-scale flotation experiments conducted using a porphyry copper ore from a mine in Finland. A comparative analysis on recovery, grade and flotation kinetics is presented on the products obtained using: i) a partially hydroxylated cellulose derivative (i.e. hydroxypropyl methyl cellulose; HPMC), ii) a commercial polyglycol-ester frother (Nasfroth240; NF240), and iii) mixtures of these two. The results show that using frothers with a total concentration of 30 ppm, the HPMC-NF240 mixtures provide advantages in terms of Cu recovery, (i.e., up to 95%), compared to the use of either NF240 (ca. 76%) or HPMC alone (ca. 1%). Interestingly, only a small proportion of HPMC mixed with NF240 was sufficient to produce a measurable increase in recovery. This improved performance was attributed to a synergistic effect of the polymer-surfactant mixture which further reduced the bubble sizes in a two-phase system compared to that of NF240. The present work offers a further step into understanding the phenomena taking place when a short chained surfactant is either substituted or mixed with a cellulose derivative, offering potential ways of exploiting this behavior for the enrichment of minerals. INTRODUCTION Froth flotation has been the predominant technology used to beneficiate sulfidic copper minerals such as chalcopyrite ever since it was invented in the late 19th century. The reason for the domination of flotation technology lies behind its versatility in selective separation as well as relatively cheap operational costs (Wills & Finch 2015). Even though flotation of sulfidic copper minerals is moderately well understood based on the broad research work done around the subject (e.g., Albijanic et al., 2015, Bournival et al., 2017, Wang et al., 2015, Mikhlin et al., 2015, to cite only a few), the modern era presents new challenges to the primary raw material industry, including questions regarding sustainability of mining operations accompanied by a need to improve the process efficiencies due to declining ore grades (Edraki et al., 2014).

Jan 1, 2019

By R. Alarcón Sch., R. Abel F.

For many years, copper cathode quality has been a priority for end consumers, since it affects the variety of products that can be obtained from them. From the beginning, physical and chemical quality of the wire bars was controlled, as this product was used to obtain wire rod and other forms of copper by wire drawing. At that time, all the electro refined cathodes were melted and casted as wire bars. Subsequently, in the 80’s, with the introduction of continuous casting furnaces, it was possible to directly produce wire rod from cathodes. From then on, cathodes quality standards were consistently increased, by the introduction of uniform criteria, among which we can identify ASTM and British Standards as well. Also, producers began to use more demanding internal standards than the existing specifications, in order to differentiate their cathodes as high quality products among customers. Today the physical aspect of cathodes, including nodules, cracks, sulfates, or others, is the first element used by end customers to assess their quality. This paper aims to show a brief vision of the evolution of quality specifications for products used to manufacture copper wire. INTRODUCTION From the beginning of refined copper production for industrial purposes, mandatory minimum quality conditions were established. These quality conditions were used as the main element to determine prices and discounts of the respective sales contracts. Reviewing the copper development history, we can appreciate that its quality requirements had been constantly evolved, so that currently refined copper has an extremely high quality standard, that allows its direct use in the production of ultra-thin cables and other products applied in the industry. In each stage, refined copper production has fostered the development of technology used in their treatment. Similarly, cathode processing technology has been evolving to minimize treatment costs in order to generate a wire rod for several uses, ranging from power cables to super conductors. In this sense, to the already known type of fusion processes of the Southwire or Asarco type (capacities over 80 kt / year), wire rod production processes of the Upcast or Rautomead type (capacities between 20-50k t / year) have been added. They immediately deliver oxygen-free wire rods. In both cases, we can conclude that the clients' requirement had evolved from a chemical criteria focus, to considering more subjective aspects, such as visual control as the first stage of inspection.

Jan 1, 2019

By Ali Roshanfekr

Linear mine-waste dumps at open-pit mine sites essentially represent expedient places to deposit large quantities of waste rock. Being in valleys in most cases, the effect of the water flowing through and out of the deposit often raises questions about their hydraulic behaviour and geotechnical stability, especially the zone of the downstream toe. In order to provide better tools to assess the behaviour of these dumps a laboratory and analytical study was conducted. Firstly, physical models were built to assess the flow capacity and hydraulics associated with the linear growth of such dumps. It was found that the elevation of the point of first-emergence on the downstream side becomes constant after the dump grows to a certain length, but that the upstream depth concurrently increases. The limits of applicability of the theories of Hansen et al. (1995, 2005) are discussed in this regard. Secondly, in analysing the seepageface downstream, two approaches for solving this spatially varied flow (SVF) problem were undertaken. Under one of the approaches links to SVF depths were merely made to the hydraulic heads of the body (interior) and flux was calculated using conventional surficial nodes after the fact, Under the other approach flux nodes were used to link the SVF algorithm to the hydraulic heads further ?inside? the body of the rockfill. Although there are inherent uncertainties, it was found that these two methods can be made to perform equally well. Research continues but it appears that a linear variation in depth can be assumed without inducing any unrealistic exit gradients in the zone of primary concern with respect to unravelling.

May 1, 2011

By M. A. Keogh

This paper reviews the physical properties that make low-density polyethylene the most practical and economical material for launder• fabrication in the majority of mine and mill applications. The basic design features and use of other launcher• materials are also discussed.

Jan 1, 1976

By R. Bridge

Mining companies are progressively finding themselves having to develop operations for more complex, deeper ore bodies, which require the use of more complicated mining and mineral processing methods. This coupled with the generally increasing trend of higher capital and operational costs have led to a need in the industry for improving ore body knowledge, mining and mineral processing. Geometallurgy is a relatively new concept that can link the three aspects, and when used effectively it is a method that can produce the necessary information for designing and building operations for reliable and optimum performance. Geometallurgy not only involves the integration of geological, mining, and metallurgical fields, but it can also be expanded to include environmental and economic information to produce a block model that can be used to obtain the best outcome in terms of plant response and plant sustainability. The geometallurgical program should not end once the block model has been populated. A detailed geometallurgical approach should be applied to all stages of the operation encompassing sample selection, through to equipment sizing and production forecasting. It can also become a useful optimisation tool thereby allowing the operation to be proactive rather than reactive against changes in the ore characteristics. With the development of metallurgical performance predictors it is possible to quantify how the ore will behave in the process plant in terms of throughput, recoveries, reagent consumption, etc. Therefore, in terms of responsible mining and sustainable resource development, a geometallurgical approach to operations is the logical step for plant development. In this paper we describe the state of the technology with respect to the application of geometallurgical modeling and its utilisation in the fields of design, forecasting and optimisation of mining operations.

Aug 1, 2013

By R. Saulters, M. Garshasb

The Transportable Moisture Limit (TML) is the copper concentrate moisture content beyond which liquefaction may occur during shipping. This study indicates that TML is a function of mineralogical characteristics of concentrate, which in turn may directly affect moisture retention properties. A comprehensive mineralogical and chemical analysis was conducted to determine the impact of composition and mineral content on concentrate’s TML. The analysis indicates that the high TML value is associated with particular minerals such as gypsum, swelling clay, muscovite and pyrite. Since higher TML values allow higher moisture contents for shipping, this property is desirable for concentrate inventory management and shipping flexibility. Scarcity of minerals that may increase TML contributes to limitations of shippable inventory. INTRODUCTION TML is the maximum moisture content of copper concentrate beyond which liquefaction may occur. Moisture content above the TML is considered a shipping hazard as it may result in loss of lives and cargo. The details of TML testing are given in ISO 12742:2007 (ISO 12742). In principle, TML is 90% of the Flow Moisture Point. The method of testing for Flow Moisture Point and TML is based on procedures that provide pulsations that simulate the cyclic force of ocean waves to determine moisture levels at which the onset of concentrate flow may occur. International Maritime Organization (IMO) provides guidelines for developing and approving TML testing and moisture determination in the context of its Moisture Management Plan (MMP) for shipment of copper concentrate cargoes (IMO 2013). The IMO regulations are specifically provided in MSC.1/Circ. 1454 “Guidelines for developing and approving procedures for sampling, testing and controlling the moisture content for solid bulk cargoes which may liquefy”. Since each port has its own operational characteristics, resource availability, peculiarities of governmental structure, and desired methods of interaction with the authorities, it is necessary to adopt the IMO guidelines to the local requirements. In order to establish a TML and MMP measurement system, it is required to implement and follow proper guidelines for the relevant procedures. For example, sampling procedures are developed in accordance of ISO 12743, “Copper, lead, zinc, and nickel concentrates – Sampling procedures for determination of metal and moisture content”. Moisture content of copper concentrate samples are determined in accordance with ISO 10251, “Copper, lead, zinc, and nickel concentrates – Determination of mass loss of bulk material on drying”. To assure strict adherence to the MMP procedures, the overall system needs to be integrated into the site QA/QC system, which would make them auditable and certified in accordance with standards such as ISO 9001, ISO 17025, and ISO 17020.

Jan 1, 2019

By H. Helmstaedt, P. Thurston, R. Harrap

"Evolution of the continental lithosphere over Earth’s 4.6 billion year history is one of the fundamental questions of geoscience. Much of the Earth’s present-day continental crust formed during the first 2 billion years, the Archean eon, of the planet’s lifetime and thus, Archean processes of lithospheric formation must be studied in order to address this question. Until recently, the processes of Archean lithospheric evolution were thought to be fundamentally different from present-day plate tectonic processes. However, subsequent evidence suggests that the growth of Archean continents may be explained in terms of modern tectonic accretionary tectonics similar to those presently operating in the southwest Pacific region. The evidence supporting this hypothesis was compiled largely by Canadian geoscientists working in the Superior Province of the Canadian Shield in northwestern Ontario, over the past 15 years. Study of Archean rocks is also economically important because the Archean rocks of the world, although comprising only a relatively small fraction of the exposed continental crust, contain much of the world’s mineral wealth, including more than half of the world’s gold, as well as significant base metal reserves. Furthermore, the vast majority of primary economic diamond deposits are derived from the lithospheric roots beneath Archean cratons.The LITHOPROBE Western Superior Transect is located within the western part of the Superior Province in northwestern Ontario (Fig. 1). The Superior Province is the largest and best exposed Archean crustal block in the world and forms the nucleus of the North American continent. The internal structure of the Superior Province records a history of the processes that formed the earliest lithospheric elements of the Earth into cratons, thus providing an ideal laboratory for investigating early crustal evolution. The Western Superior Province is characterized by a regional pattern of alternating, 100 km to 200 km wide geological belts (Fig. 2). The observed geologic relationships between and within these subprovinces have been explained in terms of a modern tectonic model of terrane accretion. Oceanic floor, volcanic island arcs, oceanic sediments and continental fragments were accreted successively from north to south against the southern margin of a cratonic nucleus (North Caribou terrane, Fig. 2) which grew steadily in size with the arrival of new terranes through geologic time. If this model is correct, it suggests that the tectonic processes operating today have been active without major variation over the past 3 billion years."

Jan 1, 1998