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By G. T. Lapidus, J. Trejo-Gallardo

A phenomenological model is presented for leaching silver from silver sulfide contained in mineral particles with ammoniacal thiosulfate solutions of copper in stirred reactors. Experimental results were used to adjust the kinetic parameters of the model, such as the reaction order and velocity. The incorporation of the cuprous sulfide-silver sulfide equilibrium at the reaction interface allowed the prediction of the conversion limits for different reagent concentrations. The information obtained from the reactor model was later integrated into a heap leaching simulation, whose results adequately describe tendencies observed in column tests, with respect to variations in copper and thiosulfate concentrations. Comp

Jan 1, 2005

By Francisco Tamargo

"This paper refers to a new process for the full recovery (above 98%) of zinc and other valuable metals (Pb, Ag, Au) accompanying zinc in its concentrates while iron is separated as a marketable product free of any harmful impurities and suitable for sale to the cement industry. The process has been especially designed to achieve the following goals: maximizing the recovery of zinc and those valuable metals that are present in most zinc concentrates (lead, silver, gold); allowing the recovery of other valuable metals such as indium or germanium that could be present in some zinc concentrates; avoiding or minimizing the need for residue disposal in safe areas as it is the common practice nowadays in the zinc industry. Finally, the process achieves the previously related goals at a competitive cost, in line with the existing more efficient operations while using conventional equipment working under atmospheric conditions. The new process can be easily implemented in those smelters using the jarosite or goethite processes as well as in those smelters using direct leaching as a part of the processing facilities. A study has already been conducted on the use of jarosite in the cement manufacturing process, in the raw mix preparation as well as for a set controller. It shows that use of clean jarosite in the manufacture of ordinary Portland cement can result in improved quality of the clinker. Jarosite showed compatibility to influence the burning characteristics of the cement raw mixes. The presence of SO3 bearing mineral phases such as natrojarosite showed the suitability of clean jarosite for use as a set controller in cement production.INTRODUCTION Iron is by far the most abundant impurity accompanying zinc in its concentrates, and consequently, iron residue disposal is a major environmental concern for many zinc smelters in the world. This is especially true during the last 30 years when environmental restrictions became more and more strict. Much research work has been carried out during the last 30 years to try to find a solution for this important issue, but with little success. Only the jarofix process represents a partial solution to this problem as jarofix is stored nearby the smelters with certain limitations as a non-contaminant residue. However, it does not avoid the need to dispose of an important amount of residues every year, representing an environmental liability. Meanwhile, the number of countries limiting or banning the disposal of iron residues generated by the zinc smelters is growing, so that the solution to this problem is becoming an urgent matter right now. At the same time, the lack of appropriate available land for iron disposal is also a major concern in many cases."

Jan 1, 2016

"Block caving is the preferred underground mining method to profitably extract massive, low-grade orebodies; however, lack of cave access inhibits understanding the rockmass response to mining, which is needed for safer, more productive operations. Combining large datasets from multiple sources with virtual reality scientific visualization (VRSV) is an alternative method for understanding complex cave behaviour, by providing virtual access to the cave. A customized VRSV module was developed at UNSW Australia to investigate rockmass response to undercut developments at a case-study block caving operation. Time/sequence effects are investigated in rockmass response to blasting, which is an important factor in hard-rock mines.RÉSUMÉ La méthode d’extraction souterraine par blocs foudroyés est la méthode préférentielle pour extraire rentablement des gisements massifs à faible teneur. Toutefois, le manque d’accès à la chambre restreint la compréhension de la réponse de la masse rocheuse à l’exploitation, ce qui est nécessaire pour obtenir des opérations plus sécuritaires et plus productives. La combinaison de grands ensembles de données de multiples sources avec la visualisation scientifique par réalité virtuelle (VRSV) constitue un autre moyen de comprendre le comportement complexe de la chambre en fournissant un accès virtuel à la chambre. Un module de VRSV sur mesure a été développé à l’Université de Nouvelles-Galles du Sud (UNSW) en Australie afin d’étudier, dans une étude de cas d’une exploitation par blocs foudroyés, la réponse de la masse rocheuse aux développements de galeries de sous-cavage. Les effets de temps/séquence sont étudiés dans la réponse de la masse rocheuse au sautage, ce qui est un facteur important dans les mines de roches dures."

Jan 1, 2016

By G. K. Quainoo

Investigation by researchers on the application of various thermo-mechanical process histories on 6000 series aluminum alloys have found improvements in mechanical properties of these alloys. However, natural aging, which is unavoidable in the automotive processing line, has been found to have deleterious effect on subsequent artificial aging properties in these alloys. In this study, the evolution of yield strength during natural aging modeled by Lloyd and Gupta has been adapted to investigate the effect of cold deformation on the natural aging kinetics in AA61 11 by means of tensile testing, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM). Also, intermetallic particles in the alloy were extracted from the matrix and XRD performed on them to ascertain their composition and their role on the kinetics in the alloy. The results show that cold work effect on the natural aging kinetics of AA6111 is in very good agreement with the model proposed by Lloyd and Gupta. The kinetics of natural aging in AA6111 aluminum also decreases with increasing level of cold work. This is attributed to dislocations serving as sinks which consume quenched-in vacancies formed during the early stages of clustering. The phases of the intermetallic particles identified in AA6111 are those of a-A15Mn12Si7 and a-A15MnSi.

Jan 1, 2007

By I. C. Edwards, D. C. Smith

THE milling plant of Bicroft Uranium Mines Limited at Ban-croft, Ontario, was one of the first in Canada to employ ion excl1ange for the selecti1•e recovery of uranium from acid leach liquors. The ion ex-change circuit started operating early in November, 1956, and by June 1 I959, had handled more than two million tons of pregnant solution containing I,830,000 pounds of U3Os. Each column had been saturated and eluted about 430 times. The ion exchange columns are the conventional fixed bed type. Uranium is eluted from the resin with a sodium chloride-sulphuric acid solution and is precipitated continuous-ly with magnesia. After filtering and drying, the precipitate, or "yellow cake," is packaged in drums for shipment to the refinery.

Jan 1, 1962

By C. Matthews, A. Vo

Australia is one of the world’s leading exporters of bulk commodities and the extensive use of sampling equipment is key to the successful management of each mining operation. At the process plant, without a full understanding of the feed, product and tails, it is impossible to fully optimise the performance of the plant, such that the metallurgical balance is often open to error. At the port, a statistically correct, bias free and compliant sampling system is crucial to ensuring exported minerals are reflective of their true value and to avoid penalties. Over the last decade, as a result of the iron ore boom, there has been high demand for reliable, representative and standard compliant solids sample systems in Australia. This paper reviews several solids sampling applications at Australian mine sites, the challenges and experience gained and how the implementation of reliable representative sampling systems has provided better understanding of plant process performance, improved plant control and overall benefits to the operations. INTRODUCTION Mining is the primary contributor to the Australian economy with Australia ranking in the top 4 in economic resources for 21 primary industrial minerals in 2016 (Britt, et al., 2017). Australia is one of the world leaders in the export of the majority of its commodities including gold, copper and iron ore (Britt, et al., 2017). Therefore, a suitable and standard compliant sampling system is essential for evaluating plant performance and content verification. At the mine and at the port, the larger iron ore miners in Australia have developed stockpile models to predict the grade of their ore down to individual blocks of the stockpile. This allows the miner to create the right blend of material for sale to their customers and ensures they are not underselling their product or at risk of penalties for impurities or low grade. As an example, the average difference between the benchmark 62% Fe and low grade 58% Fe fines at the time of this report averaged US $20/tonne according to the Metal Bulletin Iron Ore Index (Fastmarkets MB, 2019). At a shipload of 180kt this would be a variation of US $3.6M. Whilst this is an extreme example, it highlights the economic importance of producing the correct grade product and a recognised representative sample of said product.

Jan 1, 2019

By E. H. Hall

"Perhaps .I should start this talk on Arsine poisoning, by giving a brief background and history of the Bralorne Mill.The present Bralorne company started milling operations in 1932, with amalgamation and flotation, and operated continuously until 19 61 . In 19 59, it was decided to change over to cyanidation, and to use double filtration rather than counter current. The cyanide portion of this new plant was completed and went on stream in August 1961 utilizing the grinding circuit of the old flotation plant. The new grinding circuit was completed and started operating December 15, 1961.The grinding circuit consists of a 7 1 x 101 Hardinge Rod Mill, and a 7 1 x 101 Hardinge Ball Mill. In series with the rod mill is a 16"" x 24"" Denver Duplex Jig, and two of these jigs are also in parallel with the ball mill. The rod mill product is classified by a Kreb cyclone, the oversize going to the ball mill. The ball mill is in closed circuit with this same cyclone. The jig products are amalgamated daily, and the amalgam barrel tails are returned to the ball mill for regrind. Arsenious oxide (As203) is one of the reagents used in amalgamation. Approximately 39 ozs. per day is used.The cyanide circuit consists of a 481 x 121 thickener, three 24' x 24' agitators, two 141 x 161 drum filters and a Merrill Crowe precipitation unit.The Krebcone overflow is thickened to 60 - 62% solids. Hydrated lime, along with a settling agent is added to the thickener. Some of the overflow water from the thickener is returned for use in the jigs. The balance of this overflow water goes to waste. To the thickened pulp entering No. 1 agitator, barren solution is added, along with sodium cyanide and hydrated lime. Cyanide strength is held at 0. 9 - 1. 0 lbs/ ton solution and lime at 0. 8 lbs/ ton solution. The lime content usually drops to 0. 5 lbs/ ton in No. 3 agitator. The two drum filters are in series and are washed with barren solution. The discharge of No. 3 agitator is fed to No. 1 filter and the discharge of No. 1 filter is repulped in barren solution and feeds No. 2 filter. No. 2 filter discharges to tails, The filtrate is clarified, deaerated and the gold precipitated. One hundred to two hundred tons of barren solution are bled to waste each day. The ore contains 1 % Arsenopyrite and 1. 5% Pyrite."

Jan 1, 1964

By D. Y. Li, C. D. Ma, T. Zhou, T. J. Cheng

In this paper, a number of experimental tests are carried out to study the strength difference on rectangular prismatic marble specimens with different height-to-width (H/W) rations. The specimens have a nominal size of 45×15 mm in the compressive cross-section (W×T) and different heights (H = 22.5 mm, 45 mm, 60 mm and 90 mm). It is to say that the height-to-width ratios are equal to 0.5, 1.0, 1.33 and 2.0, respectively. The quasi-static uniaxial compressive tests are finished by a servo-controlled INSTRON machine (the strain rate at about 10-5/s), and the dynamic compressive tests are finished by a diameter of 50 mm cylindrical SHPB apparatus (the strain rate reaching about 101/s). The rock failure process of marble specimens is captured by a high speed camera in order to distinguish the fracture propagation behaviour. It is found that the compressive strengths increase when the H/W ratio of marble specimen changes from 2.0 to 1.0 due to the end clamping effect both for quasi-static and dynamic loads. However, when the H/W ratio changes from 1.0 to 0.5, the apparent compressive strengths decrease both for the two loading conditions. The strength decrease of short marble specimens may be attributed to the change of failure mode from shear to slabbing, which can be identified by the fracture patterns of the specimens. Based on the uniaxial compressive tests, the slabbing strength of the marble was found to be about 40% of its UCS for the specimens with a nominal height-to-width ratio of 2.0. In addition, it is found that the dynamic increase factors (DIF) are affected by the specimen’s aspect ratios. It implies that the same aspect ratios should be used to compare the dynamic and static compressive strength of rocks. Meanwhile, both the static and dynamic tensile strengths of the marble are obtained by the Brazilian disc tests. The ratio of the dynamic tensile strength to the static tensile strength of the marble is about 2.68.

Jan 1, 2015

By Robert R. MacLachlan

New underground mining technology is evolving through the use of large-diameter bore holes containing individually restricted charge weights. This article presents summary observations on cube-root scaling trials using single and rows of charge blasting in sand and in frozen ground. These observations have some bearing on the evolving underground practice, especially where charges of appropriate geometry are used.

Jan 1, 1978

By Shamia Hoque, Charles Q. Jia

Smelter slags contain valuable metals such as Co, Ni and Cu in proportions of less than 1 wt% along with about 40 wt% of Fe and 15 wt% of Si. Although aqueous SO2 is a versatile lixiviant for transition metals, dissolving the slag in aqueous SO2 produces solutions in which Co and Ni concentrations are lower than that of Fe due to the low metal/ Fe ratio in the slag. To develop the options for increasing Co and Ni concentrations the solubility of slag in aqueous SO2 was studied experimentally and theoretically using OLI, a software package for simulating electrolytes chemistry. The modeling results correlated well with experimental results. The model suggested that the species dominating the system was FeSO3, which would precipitate out as FeSO3.3H2O when the concentration of Fe+2 reached 1.22 molal and the concentration of S032- was beyond 1.4 molal. In the experiments the influence of pH and solids loading were studied. The leach solution obtained after dissolution of slag at 50% solids loading had a pH of 1.85. On raising the pH to 3, precipitation occurred. Analysis of the solution collected after the addition of alkali showed over 50% reduction of Fe, Co and Ni. XRD analysis revealed the precipitate to be of amorphous nature due to the silica present. The analysis confirmed that the precipitate was mainly FeSO3.3H2O. The paper also discusses the potential impact of the slag on the environment.

Jan 1, 2004

By W. Basuki, B. Setyotomo, L. Hakim, R. Hendrajaya

Due to high crack sensitivity of slab product of gas and oil line pipe application, its steel making process and alloy composition were evaluated and then improved to overcome its critical solidification process and reduced surface defects. The study was conducted at Slab Steel Plant Krakatau Steel. The purpose was to improve slab surface quality by reducing surface defects so that the slab surface doesn't need to be totally repaired. The method applied was by performing plant trial process, which the secondary process parameters such as alloying method and the casting parameters such as casting powder selection, metallurgical cooling, mould level control, and superheat were continuously monitored and then adjusted to the surface quality of the product. Based on the calculation of Ferrite potential of the steel, the chemical composition was designed to achieve optimum casting parameters in order to avoid high shrinkage during solidification. The results of the study are decreased surface defect quantity, and smooth casting process. The quantity of crack decreased by almost 90%. The slab surface repairing was significantly reduced from 85. % to less than 10%. These new casting parameters and developed alloy composition are then used and standardized for the mass production of the steel.

Jan 1, 2005

By J. Reinhardt, R. Uken, S. S. Chinnasamy

Au mineralization in the Kilpwal Gold Mine is confined to laminated quartz-carbonate lodes and associated alteration along the Klipwal Shear Zone (KSZ) in the upper Mozaan Group of the Mesoarchaean Pongola Supergroup. The brittle-ductile shear zone is characterized by inner and proximal hydrothermal alteration domains that are comprised of chlorite, epidote, sericite, pyrite, arsenopyrite and gold. Possible sources of gold are: (i) paleo-placer U-Au rich conglomerates from the lower Mozaan Group; (ii) the underlying mafic volcanics of the Nsuze Group; (iii) greenstone belts in the basement to the Pongola basin. Post-Pongola granites probably provided the heat to mobilize auriferous fluids into the KSZ.

Jan 1, 2011

By Jaeheon Lee

"Biooxidation of gold ores or concentrates could be a very attractive alternative to pressure oxidation (POX) or roasting to liberate the gold grains from various sulfides. Crushed heap bioleaching was successful in US and many operations using tank bioleaching of gold concentrate are currently running around the world. Many parameters need to be considered during the project of sulfidic refractory gold ore process. Capital and operation costs are among the most important ones. Run-of-mine heap biooxidation could be very inexpensive and the smaller the crush size (particle size), the more expensive the capital and operating costs for biooxidation application are expected. The capital cost of biooxidation could be a fraction of the cost for building POX plant or roaster and the operating cost could be 1/3 of POX or roasting depending on the method utilized. A new biooxidation process, Sand Farming, is introduced as an alternative to POX and tank biooxidation process. A relatively coarser particle size (P80 = 650 µm) of the process benefits the low cost of grinding against the conventional grinding size (P80 = 75 µm) for other options. The cost of Sand Farming is less than 40% of that of pressure oxidation with comparable gold recovery from the downstream process. This paper will review the laboratory scale testwork for various biooxidation process of sulfidic refractory gold ores and concentrates and provide the economic evaluation showing the biooxidation could be the most economic method without much sacrificing the overall gold recovery. INTRODUCTIONThe decreased availability and lower grade of raw materials has motivated industries to consider recovering values utilizing low cost process options. The process may treat high grade concentrates or submill grade ores that cannot be processed economically by conventional milling-flotation or leaching. Sulfidic refractory gold ores/concentrates have been economically processed by roasting, pressure oxidation, and biooxidation in stirred tank reactor. The process selection is based on a series of studies including multi-year long ore characterization and metallurgical investigations."

Jan 1, 2016

By Diego L. Romero, Joy P. Romero

"IntroductionThe purpose of this paper is to explain the theory and demonstrate the industrial applications of electrostatic separation. Wabush Mines' use of this type of processing for the concentration of iron ore is unique in the industry. Other minerals are concentrated electrostatically but the process is not widely used.Typical minerals separated by electrostatic separation techniques are:Non-ConductorsAnhydriteApatiteBariteBastnasiteBerylCalciteChrysotileCorundumDiamondEpidoteFeldsparsFluoriteGarnetGypsumHornblendeKyaniteAcmiteAugiteBrookiteCassiteriteChalcopyriteChromiteColumbiteCopperDaviditeEuxeniteFerberiteFrankliniteGalenaGoldGraphiteHematiteMica (Biotite)Mica (Muscovite)MonaziteOlivinePerovskiteQuartzScheeliteSideriteSillimaniteSpheneStauroliteSulphurTopazTourmalineXenotimeZirconConductorsIlmeniteIlmenite-( High Iron)IlvaiteKoppiteMagnetiteMarmatiteMolybdenitePyriteRutileSamarskiteSphaleriteTantaliteWolframiteWulfeniteThe limitations of this process are:1. There must be a difference in conductivity between the minerals being separated.2. The size range must not be very wide.3. The specific gravity of minerals being separated should be similar or the minerals to be pinned should be lighter. 4. The feed must be dry.5. The particle shape should be more or less uniform. 6. The feed must not be high in true middling particles."

Jan 1, 1989

By Edward I. Renouard

"THE mineral industry is constantly undergoing changes and facing challenges, and today we are in the midst of another serious one -namely, manpower requirement at every level in the mines, shops and plants. In the not too distant past we had a situation where labour was plentiful, although the equipment, by present-day standards, was quite inadequate, and that's easily understandable when you look back at the primitive methods by which our Western mines were first developed and operated, and then improved by the inventiveness and ingenuity of man.I'd like to show you a few slides from drawings made by Buck O'-Donnell which illustrate some of yesterday's methods of mining. Some of you probably had first-hand experience with some of these so you know they were tedious, time-consuming and involved a lot of heavy labour.Taking the Anaconda Company operations at Butte as an example, we can see what has happened in just the past ten years. In August of 1956, the Butte mines had 5,516 day's-pay employees and 976 salaried employees, for a total payroll of 6,492. In August of this year, there were 3,645 day's-pay employees and 605 on the salaried roll, for a total of 4,250. The number of contract miners had gone from 1,347 in 1956 to 606 in 1966 and that of other underground miners from 2,893 ten years ago to 1,149 this year. Along with these changes, however, another change of special significance has taken place, and that is in the number of skilled craftsmen, surface engineers and so on required for our operations. In 1966, we had 1,890 of these people, 600 more than in 1956 and nearly three times as many as just twenty years ago."

Jan 1, 1967

By S. Eckert, M. Reuter, O. Keplinger, D. Obiso, N. Shevchenko, M. Akashi

We report on laboratory experiments focusing on bubbling phenomena arising from gas injection through a top submerged lance (TSL) in a liquid metal layer. The objective of this study is to reveal the characteristics of the formation and behaviour of the particular bubbles at different gas flow rates and submergence depths of lance. Visualization was performed in the eutectic alloy GaInSn using X-ray radiography. Argon bubbles were injected through the injection positions at three different submergence depths. Essential parameters such as the bubble size, bubble shape, detachment frequency and the two- dimensional gas distribution in the flat vessel were obtained by image processing. The results show that the deep position of the submerged lance causes an asymmetric large-scale circulation inside the fluid vessel. Bubble detachment frequencies were calculated by Fast Fourier Transformation from fluctuations of the image intensity in the vicinity of the nozzle injection point. This frequency does not show strong variations with respect to changes of the gas flow rate and the submergence depth of the nozzle. An increasing gas flow rate results in an increasing two-dimensional projected bubble area and the occurrence of a significant number of small bubbles being trapped by the strong fluid flow in the liquid metal layer. INTRODUCTION The Top Submerged Lance (TSL) process has been an essential component of the metallurgical industry since the emergence of first concepts about 50 years ago (Floyd, 2005). The process, which is characterized by blowing reactive gas through the submerged lance into a liquid bath, was developed mainly for improving the tin smelting process and has been applied for waste treatment or the production of several metals such as copper, lead, nickel and zinc. The productivity of the reactor is determined mainly by the efficiency of the chemical reaction between the gas or solid particles and the liquid. To achieve a high efficiency requires good exchange between the gas-liquid phase and therefore a large interface area. The efficiency changes greatly with the number and size of bubbles injected from the nozzle and the extent of splashing on the free surface. The degree of turbulence in the bath plays a decisive role here. For the reason, the design of an efficient TSL process requires a profound knowledge of the fluid dynamics especially for complex multiphase flows.

Jan 1, 2019

By S. Banisi, A. R. Hasankhoei, Gh. Parsapour, A. R. Ghasemi

At the Gol-E-Gohar mining and industrial Company, a pelletizing plant, which includes two parallel dry closed grinding circuits and a pellet production circuit, produces 600 t/h. Each grinding circuit consists of a burner, a dry ball mill (6 m×13 m) and an air separator. Each ball mill consists of a 2 m-long dryer chamber and an 11 m-long grinding chamber. Iron ore concentrate is fed to the drying chamber to decrease its moisture from 2.5% to below 0.2%. The drying chamber consists of 56 flights in two rows. It was found when the feed moisture content decreased from 1.3 to 3.5%, the throughput decreased by 14% (40 t/h) indicating a low performance of the dryer. In order to improve the efficiency of the drying section, a scale down version of the dryer was constructed in a 1m diameter mill with a transparent end to make image analysis possible. It was found that because of the inappropriate veiling profile in the drying section, most of materials are not subjected to the hot gas tunnel. To overcome this problem, various flights with different geometries were physically tested and also simulated by the KMPCDEM © software. With the aim of arriving at a proper veiling profile which maximizes the particles contact with hot air, a new flight design was obtained and tested. The installation of the rectangular tooth type flights in one of the mills in the plant made the comparison of the old and new designs possible. The evaluation of the designs in a period of three months indicated 15 t/h increase in the throughput in the case of the new flight design.

Jan 1, 2016

By J. A. Meech

"The technology known as Expert Systems is being used within the minerals industry in a wide variety of problem areas. Applications include diagnosis, prediction, training, monitoring and control. Expert Systems provide a way to program computers to imitate human thinking. The construction of such systems is a straight-forward task that can be quickly learned by novices but can require a lifetime to master.To assist in the understanding and utility of this technology, a special manual bas been prepared which operates on a microcomputer under the MS-Windows environment. The manual covers all aspects of Artificial Intelligence of relevance to Expert Systems. A hypertext system allows users to probe as d•~ply as needed to achieve understanding or to simply skim the surface of the knowledge to obtain a quick overview of subjects. The manual was developed under the sponsorship of the Mineral Sciences Laboratory of CANMET and is available from the Mining and Mineral Process Engineering Department at the University of British Columbia. Annual updates are planned to keep abreast of new developments in this rapidly changing technology. RESUMELa technologie: des Systèmes Experts est utilisée par l'industrie minière pour résoudre une grande variété de problèmes. Les domaines d'application comprennent le diagnostic, la prédiction, la formation, la surveillance et le contrôle des procèdes. Les Systèmes Experts permettent d'écrire des programmes d'ordinateur qui imitent le processus de la pensée humaine. La construction de tels systèmes e:st une tâche qui peut être apprise rapidement mais qui peut prendre des années à maitriser.Pour aider à mieux comprendre et utiliser cette technologie, un manuel spécial opérant sur microordinateur dans l'environnement Windows a été développe. Le manuel couvre tous les aspects de l'intelligence artificielle qui concement les Systèmes Experts. Un système ""hypertexte"" permet à l'utilisateur d'étudier un sujet en profondeur ou de simplement couvrir une grande variété de sujet en surface. Le manuel a été développe avec l'aide financière du Laboratoire des Sciences Minérales de CANMET et est disponible au Département de Génie Minier et Minéralurgique de l'Université de la Colombie Britannique. Des mises à jour annuelles sont prévues de manière à couvrir les changements et nouveautés de cette technologie en évolution."

Jan 1, 1993

By S. Maleksaeedi

On-site evaluation of strength using hardness is common for different materials. The lack of such relation for aluminum alloys has always been felt. In this work, a finite element analysis of plastic deformation and its distribution in Brinell hardness testing is presented. The analysis has been performed for different strength levels of aluminum alloys. By utilizing the Von Mises equivalent strain in hardness, it is tried to derive a correlation between hardness and strength values for the alloys under consideration. The derived correlation is verified using the experimental values available in literature.

Jan 1, 2004

By J. M. Turnbull

THE primary objective of the young graduate, after the war, will be to obtain a suitable position within the Industry, with adequate pay and opportunity to advance. The positions available to meet this demand will depend on the magnitude and organization of the industry. The size of the mining industry, in particular, will depend on a number of factors, including depletion; new discoveries of mineral deposits; beneficiation of new kinds of mineral deposits, based on research; technical improvements, also based on research, enabling the mining of lower grade deposits; and complex social factors. The organization of the industry will depend on its control and management, which may be greatly affected by social conditions and changes, and may include a wider or a narrower use of technical services. The corresponding training or qualifications of graduates, to meet these conditions, calls for a consideration of educational requirements and facilities in relation to the conditions that are likely to occur. Some forecast of the probable future of the Industry, after the war, based on consideration of. the above factors, is necessary as a basis of discussion, since the graduate must find his place in the industry of that time, and find his work in maintaining and improving it, within the existent social framework. Social factors are pressing and? important at present and their future impact is uncertain. In considering these, a few quotations and extracts may be in order. "A new economic order, based on free access to the sources of raw materials, means free use of the world's wealth by all civilized nations" (The Pope. Also advocated by Churchill and Roosevelt in the Atlantic Charter). "Every citizen should have a voice in the conduct of business or industry which is ?carried on by means of his labour" (Archbishop of Canterbury).

Jan 1, 1943