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By L. H. Shang

The 319 Al-Si alloy is one of the most prominently used aluminium-based alloys in motor vehicle and engine applications, Microporosity present in 319 alloy castings reduces the load bearing capacity of the castings, The quantitative prediction of microporosity levels in Al-Si castings has been a subject of much interest for several years. In this research a new criteria function, tf 1,98 R13° (tf: local solidification time, R: cooling rate) was developed by multiple regression analyses, correlating thermal data from simulation studies to experimentally obtained microporosity values. This new criteria function gives a general prediction of microporosity in 319 Al-Si castings.

Jan 1, 2005

By Dielle Cristine Toledo Costa

Os aços austeníticos 304L quando processados tem suas propriedades mecânicas afetadas pelas transformações martensíticas induzidas pela deformação plástica (efeito TRIP). O objetivo deste trabalho foi avaliar esse comportamento em corpos de prova que sofreram deformações gradativas por meio de ensaios de tração uniaxial a partir de diferentes técnicas de análises microestruturais e mecânicas, a saber: ferritoscopia, difração de raios-x e ultramicrodureza. Os resultados obtidos foram satisfatórios e permitiram estimar o efeito da deformação na transformação martensítica e comparar as técnicas utilizadas.

Aug 8, 2018

By Felipe das Dôres Machado

No processo de fabricação de aço, o distribuidor possui grande importância na questão limpeza inclusionária, principalmente, quando se trata da produção de aços limpos (clean steel). As inclusões podem afetar negativamente as propriedades mecânicas e metalúrgicas do aço. Estudos realizados em modelos físicos e/ou matemáticos vêm sendo aplicados com intuito de propor medidas que melhorem a capacidade do distribuidor na remoção de inclusões presentes no aço. Este trabalho tem como objetivo principal qualificar o escoamento de um distribuidor e quantificar a remoção de inclusões do mesmo. Um modelo físico de um distribuidor de lingotamento contínuo de tarugos construído em acrílico e que respeita a similaridade de Froude e Reynolds é utilizado para os ensaios. A quantificação das inclusões é realizada por meio de um ensaio que envolve um sistema de injeção de partículas de polietileno na entrada no distribuidor e outro sistema de coleta dessas partículas na saída do distribuidor no qual as amostras coletadas, posteriormente, são secadas e pesadas. Com os resultados obtidos pretende-se compreender o efeito dos parâmetros propostos sobre a remoção de inclusões e permitir a utilização de uma ferramenta capaz de avaliar a qualidade de aços no que se refere à passagem de inclusões na saída do distribuidor.

Jul 30, 2018

The Round Table on Qualities of Pig Iron, under the auspices of the Joint Committee on Qualities of Pig Iron, which is made up of members of the American Institute of Mining and Metallurgical Engineers, the American Foundrymen's Association, the American Society for Testing Materials, the Gray Iron Institute, and the Malleable Iron Institute, was held at the Palmer House, Chicago, III., on Oct. 1, 1935. Prcoeedings R. H. SwEEtseR,* New York, N. Y.—Seven years ago last June, in Chicago, we had a round table on qualities of pig iron1, and at that time the foundrymen were out with their battle-axes for the blast-furnace men, and the open-hearth men were doing the same thing. After that meeting there was really a determined effort to find out about the qualities of pig iron, and great progress has been made all along the line. This afternoon we want to have a frank discussion of the qualities of pig iron, whether it is the molten pig iron going into the steel plant, or cold pigs going to the different foundries. We ought to hear something from Dr. J. T. MacKenzie, who is chairman of the Joint Committee, and from Mr. R. E. Kennedy, the Technical Secretary of the American Foundrymen's Association. J. T. MacKEnzie,† Birmingham, A1a.—As a result of that meeting in Chicago, there was considerable agitation in the Foundrymen's Association to develop a set of tests for pig iron. One of the difficulties was that nobody talked the same language on shrinkage, draws, live iron, dead iron, and so forth, which were the main complaints against pig iron. By request of a committee of the Foundrymen's Association, the Bureau of Standards ran a comprehensive set of tests that did develop the principles governing the optical pyrometer as applied to cast iron and pig iron. Then the Bureau went on further with the fluidity test, and developed a method for the absolute changes of volume at the freezing point. There is one serious gap in the yardstick, which has never been developed, and that is the tendency to draws from heavy sections to light. Everyone who has worried about the differences of section, and sponginess in changes of section, realizes that the

Jan 1, 1936

The Round Table on Qualities of Pig Iron, under the auspices of the Joint Committee on Qualities of Pig Iron, which is made up of members of the American Institute of Mining and Metallurgical Engineers, the American Foundrymen's Association, the American Society for Testing Materials, the Gray Iron Institute, and the Malleable Iron Institute, was held at the Palmer House, Chicago, III., on Oct. 1, 1935. Prcoeedings R. H. SwEEtseR,* New York, N. Y.—Seven years ago last June, in Chicago, we had a round table on qualities of pig iron1, and at that time the foundrymen were out with their battle-axes for the blast-furnace men, and the open-hearth men were doing the same thing. After that meeting there was really a determined effort to find out about the qualities of pig iron, and great progress has been made all along the line. This afternoon we want to have a frank discussion of the qualities of pig iron, whether it is the molten pig iron going into the steel plant, or cold pigs going to the different foundries. We ought to hear something from Dr. J. T. MacKenzie, who is chairman of the Joint Committee, and from Mr. R. E. Kennedy, the Technical Secretary of the American Foundrymen's Association. J. T. MacKEnzie,† Birmingham, A1a.—As a result of that meeting in Chicago, there was considerable agitation in the Foundrymen's Association to develop a set of tests for pig iron. One of the difficulties was that nobody talked the same language on shrinkage, draws, live iron, dead iron, and so forth, which were the main complaints against pig iron. By request of a committee of the Foundrymen's Association, the Bureau of Standards ran a comprehensive set of tests that did develop the principles governing the optical pyrometer as applied to cast iron and pig iron. Then the Bureau went on further with the fluidity test, and developed a method for the absolute changes of volume at the freezing point. There is one serious gap in the yardstick, which has never been developed, and that is the tendency to draws from heavy sections to light. Everyone who has worried about the differences of section, and sponginess in changes of section, realizes that the

Jan 1, 1936

By K. P. V. Lei

The Bureau of Mines investigated molten salt electrorefining 'n helium atmosphere cells as a means for the production of ductile vanadium. 'Electrolytes composed of NaCl-VCl2, LiCl-NaCl-VCl2, BaCl2-KCl-NaCl-VCl2 KCl-LiCl-VCl2, and CaCl2-NaCl-VCl2 were tested. Two electrolytes, KCl-LiCl-VCl2 and CaCl2-NaCl-VC12, were selected for laboratory-scale production tests. A molten salt electrorefining process was developed for the production of ductile 99.6 percent vanadium from a commercial 90-percent grade. Using the CaCl2-NaCl-VC12 electrolyte, an 87-percent recovery of ductile vanadium was made; an 85-percent recovery was made with the KCl-LiCl-VCl2 electrolyte.

Jan 1, 1967

By S McKnight, L Koroznikova, S Hall

Mineral sands represent an important new resource being developed in the Murray Basin, including parts of western Victoria. This paper will outline a simple methodology for mineral sands characterisation, developed as part of the AMIRA-managed project P777 æThe Development of Heavy Suspension Techniques for High Density Separations (Replacement of ClericiÆs Solution)Æ. This project is currently sponsored by three multinational mining companies (De Beers Consolidated Mines, Iluka Resources Limited and Rio Tinto Limited) and is developing an innovative laboratory mineral characterisation procedure that will allow the replacement of the currently employed highly-toxic chemicals.Mineral sand resources almost always contain more than one valuable (and relatively heavy) mineral. Titanium minerals are found with a large range of titanium contents, giving rise to density variation and often subjective mineralogical descriptions. Companies tend to rely on laboratory heavy liquid separation in the evaluation of samples arising from exploration, mining or metallurgical processes. Unfortunately, there are only a limited number of high density (æheavyÆ) liquids and these tend to be more toxic as their density increases. Low-toxicity inorganic solutions, based on tungsten compounds, have been developed that can be utilised at relative densities (RD) up to 3.0. However, beyond this value currently only organic liquids can be used. Diiodomethane (methylene iodide) having a relative density of 3.31 is commonly used; however, this presents significant health and safety hazards. Mixtures of thallium formate and thallium malonate were found in the early 1900s by Clerici to provide liquids having specific gravities between 4.0 and 5.0, hence æClericiÆs solutionÆ. For the characterisation of the heavy components of mineral sand deposits (eg anatase sg 3.9, rutile sg 4.2, ilmenite sg 4.4 û 4.7 and zircon sg 4.6 û 4.8) there is currently no heavy liquid alternative to ClericiÆs solution. ClericiÆs solution is highly toxic and testing is now conducted by very few laboratories worldwide with costs reflecting the chemical costs (though extensive efforts are made to recover and reuse the liquid, plus the requirement of its removal from the mineral samples), the infrastructure costs and health and safety regimes (eg blood testing of exposed staff, inventory management). A simple laboratory technique of density fractionation is being developed, employing suspensions of fine tungsten carbide particles in lithium heteropolytungstate (LST) solutions, that can replace ClericiÆs solution in the evaluation of fine mineral sands samples (eg -250+150 microns). The developing methodology that can achieve low-cost, low-toxic separations at relative densities above 5.0 will be outlined and the comparison of results with ClericiÆs solution presented.

Jan 1, 2006

By Stephen C. Blair

Laboratory permeability measurements at elevated pressure and at temperatures ranging from 20º to 150°C have been conducted on samples of Ironton-Galesville sandstone. The purpose of this testing was to identify and characterize important physicochemical processes occurring in association with the injection and withdrawal of heated ground water at the U.S. Department of Energy's Aquifer Thermal Energy Storage (ATES) field site in St. Paul, Minnesota. Results indicate that permeability decreased significantly as temperature was increased and that dissolution of the dolomite and silicate cementing agents and accompanying changes in mechanical properties may occur in the heat storage aquifer at St. Paul. Further, loss of permeability with temperature in laboratory samples may be caused by the change in the mechanical structure of the sample. Tests at ambient temperature to evaluate the effect of particle migration under conditions of reversed flow indicate that this process will not significantly impair formation permeability at the St. Paul site.

Jan 1, 1984

By R. W. Lankston

Uranium mill tailings disposal facilities present unique problems with respect to siting, design, and long-term stability because their contents remain potentially hazardous for 100,000 years. Dawn Mining Company, operator of a uranium mill in Washington, undertook geological and geophysical studies relative to planned expansion of existing disposal facilities. Seismic refraction and reflection, resistivity, and ground magnetics data were integrated with limited drill data to determine the configuration of Quaternary sediments and the underlying basaltic and granitic bedrock. Analysis of multiple reflections and magnet modelling on a micro-computer with CRT graphics added detail to the interpretation.

Jan 1, 1980

By D. R. Walker, M. C. Shaw

Dimitri Kececioglu (Allis-Chalmers Manufacturing Co., Milwaukee)—The idea of applying metal cutting theory to comminution and vice versa is very impressive. Among others, the demarcation of wheel-grinding data into two regions, namely Kick's and Rittinger's, draws attention here. A study of Figs. 6 to 9 shows the following: In Fig. 6, 1 point out of 8; in Fig. 7, 4 points out of 26; in Fig. 8 only 1 point out of 13; and in Fig. 9 practically none out of 13 points fall out of curve No. 2. Also when grinding particles smaller than 5x10." in. it is difficult to measure very accurately the grinding forces, chip geometry, and particle size. In view of the above it would be difficult to make a positive and distinct demarcation of the Wheel-grinding data into two regions, namely, Kick's and Rittinger's. The idea of using machine grinding to determine the comminution properties of materials is indeed unique. The following cautions come to mind, however, regarding applicability of machine grinding data to comminution: 1—Grinding gives uniform particle size, whereas comminution gives a variety of particle sizes in the same process. The fact that grinding gives uniform particle size is not necessarily an advantage because in comminution the overall energy under actual comminution is desired and comminution invariably results in the production of a variety of particle sizes. 2—In grinding, a small particle is ground off a comparatively large surface. In comminution small bodies are broken down to smaller bodies. This makes it difficult to establish a concept of reduction ratio in machine grinding. 3—The mechanics of machine grinding involve direct shearing action under very high strain and comparatively high compression at the shear zone, whereas: comminution involves direct dynamic compression and surface friction with comparatively little strain and shear. Consequently the mechanics of machine grinding appear to be different from those involved in comminution. Hence one might arrive at erroneous con- clusions when comminution characteristics are eval-uated from machine grinding results. It is noticed also that functions other 'than Eq. 16 which do not involve the concept of direct proportionality of useful energy input to new surface area created (Eq. 2 and particularly Eq. 12) may be derived to fit the, data of curve No. 2. One such relationship may be u = ct-", where c is a positive constant and n is a positive constant less than unity. This, of course, is made possible because data of a very small range. of particle size are being fitted by the curves of No. 2 and the hereby suggested relationship. A sound comminution theory should be applicable to a relatively large range of particle size. George B. Clark (Department of Mining Engineering, University of Illinois)—While the experimental work of Walker and Shawin this article is of intrinsic value in revealing certain fundamental aspects of machine grinding, milling, and related processes and in adding to the store of information concerning the comminution of solid materials by this particular process, it appears doubtful that the results of their research can be employed to verify either Kick's or Rittinger's theories. Both these laws were originally developed and proposed on the basis of very simple, idealized hypotheses. The creation of parallel idealized physical laboratory conditions which would be required for either their proof or disproof appear to be well beyond the scope of human ingenuity, at least at present. One great weakness of the imputed verification is that the spread of the points plotted on the graphs is not sufficient to permit accurate 'curve fitting. The range of particle sizes included in the belt and wheel grinding is not extensive enough to show any general trends, particularly for the horizontal portion of the curves, said to represent Kick's laws. That the milling; grinding, and turning data obtained by Walker and Shaw for both metals and minerals happen to comply with. certain interpretations of these two theories under certain specialized conditions

Jan 1, 1955

By Richard D. Hagni

The United States is dependent upon foreign sources for more than 93% of its bauxite and alumina supply. Domestic production of bauxite, which comes from Alabama, Georgia and Arkansas, is limited to those bauxite ores containing less than about l ½ % iron. Bauxites with higher iron contents are generally not utilized because they cause problems in bauxite calcining and especially because they produce undesirable brick discoloration and cracking. In order to improve beneficiation and expand the utilization of high-iron or ferruginous bauxites, a mineralogical and textural study has been conducted on selected samples from the Eufaula, Alabama, bauxite district. Reflected light microscopic, petrographic, and X-ray techniques have shown that a variety of iron minerals are present, including hematite, goethite, lepidocrosite, siderite, pyrite, marcasite, and ilmenite. Although the iron minerals may be locally concentrated into concretions and pisolites, most occur as very fine grains that are disseminated and show a variety of intergrowths. Mineralogical and textural observations indicate that the fine-grained iron mineral grains may be amenable to high gradient magnetic separation.

Jan 1, 1981

By E. J. Gleim

Many people consider the mining of coal to be an extremely hazardous occupation; but it should be remembered that most large industries have to meet special conditions which, if not dealt with properly, might become hazards to life and property. Mining men may not always be fully aware that some practices and certain equipment that is incorrectly designed or maintained can lead to dangerous conditions. In endeavoring to help the coal-mining industry to prevent accidents and disasters, the Bureau of Mines has engaged in a program of education on conditions and practices that must be avoided. An effective way to teach safety is by visual demonstration. For example, it is generally known that certain kinds of electrical flashes have ignited explosive atmospheres in mines, but actually to see and hear explosions caused by electrical sparks of different size and character under laboratory control is likely to teach a much more emphatic and lasting lesson than would be learned by merely reading about them. The interest manifested by those who witness the demonstrations seems to prove that this is true. The purpose of the demonstrations is not to discourage the use of electricity in mines, but rather to indicate what types of equipment (including some generally regarded as harmless) can ignite gas and what safeguards have been developed to prevent such ignitions. It is hoped that this information will improve the ability of mining men to cope with underground hazards.

Jan 1, 1937

Application of flotation for the removal of hydrophobic compounds from soils was studied. Bench scale flotation tests were conducted on artificially contaminated soil, using both conventional mechanically agitated machine and flotation column. Flotation parameters tested include surfactant collector type, conditioning time, flotation time, surfactant dosage, pulp pH, solid/liquid ratio in conditioning and pulp temperature. It is found that with conventional flotation 74% removal of the contaminant was achieved from soil particles in the range of 75-830 µm; with column flotation up to 80% of oil could be removed from the 250-830 µm soil fraction, and 65% from the 75-830 µm fraction. Flotation was found to have considerable potential for cleaning up contaminated soils.

Jan 1, 1998

By Guilherme Filipe de França Vieira

Os aços inoxidáveis ferríticos apresentam menor custo que os austeníticos, pois praticamente não possuem níquel em sua composição, e seu custo está diretamente ligado ao preço do níquel que possui alta volatilidade. Devido a sua capacidade de resistência à corrosão, estruturas são construídas a partir deste material e descartam a necessidade de revestimento contra corrosão. O trabalho tem como objetivo caracterizar o comportamento mecânico da liga de aço inoxidável ferrítico, UNS S43932. Metalografia e dureza foram realizadas para caracterizar o material e sua microestrutura. Por meio de ensaios mecânicos de tração, no equipamento MTS 250 kN, analisando sete corpos de prova, obtiveram-se propriedades como: módulo de elasticidade, tensão de escoamento, tensão limite de resistência à tração, tensão de ruptura, alongamento, redução de área, coeficiente de resistência e expoente de encruamento, através da curva monotônica. Pode-se observar que as propriedades mecânicas identificadas estão coerentes com aquelas fornecidas pelo fabricante, o que validou os ensaios e possibilitou a adicional obtenção de propriedades mecânicas referentes ao comportamento da parcela plástica.

Aug 16, 2017

By Sarah Bélair, Denis Beltrami, Valérie Weigel

"Mabounié is a polymetallic deposit in Gabon containing niobium (1.2%), tantalum (0.03%), rare earth elements (REE) (1.4%) and uranium (0.03%) that are mostly carried by Pyrochlore minerals. Classical route for niobium recovery is a pyrometallurgical process that consists in pyrochlore flotation, dephosphorization of the niobium concentrate and aluminothermy to obtain ferro-niobium. Pyrochlore concentrates can also be treated by a hydrometallurgical process with a mixture of sulfuric and hydrofluoric acid leaching followed by solvent extraction to separate niobium and tantalum. However, the first process does not allow recovering REE and the second one is not environmentally friendly because of the use of HF.ERAMET is looking for new opportunities on strategic metals market and has recently developed a hydrometallurgical process for the recovery of all these metals based on a sulfuric acid treatment of the ore. After solubilisation of the valuable elements, niobium / tantalum are precipitated as a concentrate (12% w/w Nb and 0.3% w/w Ta) while REE (2.7 g L-1) and uranium (90 mg L-1) remain in solution. Nearly 90% of REE are recovered from the solution by conventional REE double salt precipitation [NaREE(SO4)2.xH2O) method but some REE still remain in solution as this method does not allow to quantitatively recover medium (Sm, Eu, Gd, Tb, Dy) and heavy (Ho, Er, Tm, Yb, Lu, Y) rare earth elements. From the different process routes studied (solvent extraction, precipitation, ionic exchange etc.), an innovative method has been developed and patented to recover REE residual concentration in solution. This is based on an aluminum removal step followed by precipitation of REE as REE phosphate concentrate (REEPO4) by phosphate addition into solution. The phosphate concentrate is then purified according to the conventional monazite treatment, i.e. caustic conversion and REE solubilisation in acidic media."

Jan 1, 2016

By O. A. Paulson, D. D. Runnells, D. P. Dupon, K. J. Bruxvoort

Background groundwater quality is often used to drive remediation programs at sites with waters that have been affected by mining activities. In the past, these levels were sometimes chosen without rigorous statistical and geochemical analysis. A probability-distribution approach was used at the Sweetwater Uranium Project to separate a large set of geochemical data into populations that represent contribu¬tions from different sources. Natural background populations were identified for major ions, metals and radionuclides, and these were submitted to the US Nuclear Regulatory Commis¬sion (NRC) to modify the extent of a corrective-action pro¬gram and to establish control limits for future monitoring.

Jan 1, 2000

By Francisco Necy Alves Júnior

Os aços inoxidáveis superduplex (AISD) aliam boas propriedades mecânicas e resistência à corrosão, possuindo um vasto campo de aplicação na indústria petroquímica. Geralmente, os reparos dos equipamentos são realizados por soldagem, sendo importante a seleção de parâmetros. É de suma importância a obtenção do teor adequado de ferrita no metal de solda, sendo que a variação da energia de soldagem pode influenciar de forma direta a microestrutura e resistência à corrosão. Logo, este trabalho teve como objetivo avaliar os efeitos provenientes da variação de parâmetros de soldagem nas características do AISD UNS S32750. Foi avaliado o balanço de fases, relacionando esse efeito com a resistência à corrosão. Foram realizadas soldagens em chapas pelo processo TIG autógeno em 3 níveis de energia de soldagem (5, 10 e 18 kJ/cm), variando a corrente e velocidade de soldagem, de modo a obter 5 condições e a possibilidade de analisar as variáveis-resposta com essas variações isoladamente. A análise da microestrutura foi realizada por microscopia ótica e o teor de ferrita foi quantificado pela utilização de duas técnicas: ferritoscópio e quantificação por imagem. Foram realizados ensaios de temperatura crítica de pite para análise de resistência à corrosão. Concluiu-se então que o acréscimo de energia pela variação da velocidade de soldagem acarretou no aumento no teor de ferrita, ocasionando a redução da temperatura crítica de pite, sendo estes observados na fase ferrítica.

Aug 7, 2018

By Hongqiang Wang, Qingliang Wang, Eming Hu, Zhiwu Lei, Fang Hu, Rui Zhang, Wei Hou

Pyrite, a mineral associated with uranium ore, is closely related to uranium leaching. In this study, Ozone micro-nano bubbles (OMNBs), as an environmentally friendly advanced oxidation technology, were used for the first time to oxidize pyrite under experimental conditions to improve the leaching rate of uranium. A laboratory-scale agitation leaching experiment of pyrite was carried out with a pH of 1.0–3.0, gas flow of 1–3 L/min, ozone generation rate of 0.55–2.22 mg/s, and pyrite concentration of 0.1–5.0 g/L for 1 h. By adding three different co-oxidant: Mn(II), Mn(IV), and Fe(III), it was found that only Mn(IV) increased the oxidation rate of pyrite by 21.7%. The results of the scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) show that the formation of Fe(III)-O film on the surface of the ore suppresses the oxidation rate of pyrite to a certain extent. Pyrite can be rapidly oxidized up to 57.6% by OMNBs, which is beneficial to uranium leaching. This method is expected to be used for in situ acid leaching of uranium with OMNBs injected into the ground.

Jan 3, 2022

By Alisson Paulo de Oliveira

Incentivado pela diversificação dos produtos em aço, a demanda por graus cuja composição química esteja próxima da faixa peritética, tais como os aços HSLA (High Strength Low Alloy) e AHSS (Advanced High Strength Steel), tem aumentado. As crescentes exigências nas propriedades mecânicas e a redução de custo nas ligas são as razões para que esses aços sejam projetados próximos à faixa peritética, com o teor de carbono entre 0,09 e 0,16%. A produção de placas do aço ASTM A588-B, com o teor de carbono visado igual a 0,10%, apresentava expressiva variação do Nível de Aço no Molde (Ou Mould Level Fluctuation, MLF), aumentando a probabilidade de ocorrência de “Break-Out” (Rompimento de Pele) e a redução da qualidade de superfície das placas, com eventual ocorrência de Trincas Longitudinais. Outra limitação é a impossibilidade de troca de largura das placas, dependente da estabilidade do processo de Lingotamento Contínuo. Serão discutidas as ações tomadas visando a redução do MLF, baseada em alterações no Projeto de Liga, a comparação entre variáveis-chave do processo de Lingotamento Contínuo de Placas em dois cenários de Projeto de Liga além dos impactos em características de Propriedades Mecânicas do produto laminado, no caso bobinas processadas em Laminador Steckel.

Oct 30, 2017

By G D. Richmond, J C. Chomley

Copper has been mined intermittently at Gunpowder, north of Mount Isa, since 1927. Most ventures have had some initial success but fluctuating copper prices, the small-scale of the operations and the remoteness of the site led to closures or sale. Processing routes have included direct sale of high grade ore, flotation of oxide and sulphide concentrate, and copper cement production from mine solutions. Copper cathode has been produced by heap and in-place leaching coupled with solvent extraction and electrowinning (SX/EW). Aberfoyle Limited recently purchased the Gunpowder operation and is expanding operations. An innovative high recovery tank leaching process, including a low temperature, low pressure autoclave, has been adopted. Copper cathode will be produced from an expanded solvent extraction/electrowinning plant at approximately 45 000 tonnes per year. The combination of expanded throughput and high metal recoveries will make Gunpowder a cost competitive producer.

Jan 1, 1998