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By F. Stober, D. Wanblad, J. Ndlovu, L. R. Nelson, L. P. S. de Villiers

The single six-in-line furnace of the Polokwane Smelter is the largest installed high-intensity furnace for platinum group metals (PGM) base metals sulphide smelting in the world. The furnace employs state-of-the art technology to deliver a planned throughput of 650 000 t/a dry concentrate at a design 68 MW power input. This furnace, at double the capacity of previously existing PGM furnaces, offers low unit operating and capital cost through the resulting economies of scale. Key features of the design include:

Jan 1, 2005

By Fumitaka Tsukihashi

Phase diagrams of the CaO-SiO2-FeOx-MgO, Al2O3 systems arc necessary for the analysis of copper smelting reactions and sintering process of iron ore. The effect of MgO and Al2O3 addition on the liquidus of the phase diagram of the CaO-SiO2-FeOx system at low oxygen partial pressure was observed. The liquid phase area changed bi the addition of MgO and Al2O3 with a changing oxygen partial pressure from 10-8 to 10-3 atm (10-3 to 10 2 Pal at 1573K. The effect of Fe3+ / Fe2+ ratio on the melting mechanism is discussed.

Jan 1, 2003

By A. J. MacRae

Metallurgical furnaces are made up of complex multi-component systems that must function either together or in parallel for safe, and reliable operation. Thermal expansion of single material components experience induced stresses during heating and cooling, which can lead to cracking or failure. Multi component elements and systems can experience significant thermally induced stresses during both steady state and transient temperature conditions. Examples pertaining to temperature effects on refractory, copper cooling blocks, furnace shells, and complete systems will be discussed. The purpose of the paper is to highlight how stresses and strains are developed due to differential thermal expansion.

Jan 1, 2015

By Guiming Yang, Xiaoxian Huang, Zhiyun Ji, Min Gan, Lishun Yuan, Xiaohui Fan, Zhiyuan Yu

"The roasting characteristics of hematite pellets containing MgO were studied where magnesia powder, serpentine and magnesite were used as magnesium-additives respectively. The mechanical strength of both preheated and roasted pellets decreased when MgO content increased, which implied the addition of MgO had an adverse effect on pellet consolidation. By adding flux containing CaO, the mechanical strength of both preheated and roasted pellets were improved. The addition of calcium flux facilitated the formation of calcium ferrite and provided a certain amount of liquid phase, resulting in faster diffusion ofMg2+ and Fe3+. The result showed that diffusing speed of Mg2+ was enhanced by 1.48 times, and rate constant of Fe203 crystalline growth was enhanced by 62% when basicity was around 0.4. Improvement of mineralization degree and recrystallization of Fe203 assisted in consolidation of hematite pellets containing MgO.IntroductionOxidized pellets are ideal iron-bearing burdens in blast furnace. At present, magnetite is the main raw material for oxidized pellet production in China. However, as the rapid development of iron and steel industry, resources of magnetite have been depleted and cannot satisfy the requirement of pellet production. Using hematite concentrates to produce oxidized pellets has become a trend [1, 2]. Many pellet enterprises abroad nowadays have adopted high proportions of hematite concentrates when producing oxidized pellets, e.g. the percentage is 100% in a lot of Brazilian factories [3, 4]. But high proportion of hematite concentrates will lead to low mechanical strength and high reduction swelling index of pellets. Some studies show that Mg-bearing pellets have excellent metallurgical properties, and the reduction swelling phenomenon can be solved by adding fluxes containing MgO [5, 7]. However, there are problems such as low pellet strength and bad roasting characteristics for MgO-bearing pellets, which remains an obstacle in pellet industry. Hence, it's vital to undertake the study on strengthening measures for indurations of Mg-bearing hematite pellets."

Jan 1, 2013

By Jr. Foot

The Bureau of Mines, U.S. Department of the Interior, investigated flotation methods for recovering fluorite and byproduct beryllium from the Fish Creek deposit of Nevada. The preferred method includes (l) fluorite rougher and cleaner flotation, (2) de sliming at 20 micrometers, (3) muscovite flotation, (4) silicate flotation, (5) hypochlorite wash of silicate concentrate, and (6) beryllium rougher and cleaner flotation from the silicate concentrate, Laboratory results showed that over 94 pct of. the fluorite was recovered in a concentrate containing 96 pct CaFz. Beryllium flotation produced .concentrates .containing in excess of 5 pct BeO with recoveries over 70 pct. A 1.00-lb/h continuous flotation unit was constructed to demonstrate this procedure,

Jan 1, 1985

By Mei Yang, Wei Gao, Jian Yang, Qingcai Liu, Wenchang Xi

"TiO2 has been loaded on cordierite porous ceramic to prepare the SCR catalyst carrier by using both APCVD and sol-gel technology. In APCVD method, TiC14 and O 2 were used as reaction precursor. TiC14 was gasified by using N2 as carrier gas which was controlled to 500sccm. Its reaction temperature and reaction time were limited to 773K and 30min respectively. The physical properties, SEM and SEM-EDX of the TiO2-cordierite carrier and the properties of SCR catalysts prepared by these carriers have been tested. The tests showed that TiO2 loaded by APCVD method were of graininess shape and even accumulation. The loading rate of TiO2 and the specific area of carrier sample were increased 114% and 21 % respectively comparing with sol-gel technology. In the result of sol-gel method, the maximal difference of Ti content was 66.92%, while the result of APCVD method was 18.89%. It demonstrated that TiO2 was uniformly attached with the cordierite ceramic by using APCVD method, which would ensure more active ingredients well loaded on the Ti02-cordierite carrier. This difference made the denitrification ratio of catalyst prepared by APCVD method was 8.1 % higher than that of catalyst prepared by sol-gel method.IntroductionIn recent years, the emission of NOx, which were caused by coal-fired power plants, has gotten more and more attention. SCR (selective catalytic reduction) is the most effective technology to DeNOx [ll. The core technology of it is the catalyst. The SCR catalyst usually uses Ti02 as the carrier, and V2O 5 as the active component [2, 3] . However, the thermal stability and mechanical properties of TiO2 carrier are unstable, which would influence the performances of the catalyst. The commercial catalyst generally uses WO3 or MoO3 to promote its heat stability at present [4-7] Besides, TiO2 is expensive. Compared with TiO2, the cordierite is of good thermal stability and lower price. So loading Ti02 on cordierite porous ceramic as carrier to produce SCR catalyst is of good prospects [S, 91 • Currently, TiO2 is usually loaded on cordierite by the sol-gel method. But some research has shown that the sol-gel method easily reduced the loading performances of TiO2, such as distribution, combination, etc. APCVD (atmospheric pressure chemical vapor deposition) has many advantages to preparing TiO2 films, such as high bonding strength, fast reaction rate and so on [l0-13l_ In this paper, TiO2 has been loaded on cordierite porous ceramic to prepare the SCR catalyst carrier by using both APCVD and sol-gel methods. The properties of the carriers prepared by the two processes have also been compared."

Jan 1, 2011

By Dmitriy Kim, Natalya Ibragimova, Galina Sedelnikova

Gold and copper are lost in flotation tailings in mineral processing of copper-zinc-pyrite ores. Large resources of precious and base metals have accumulated in tailing ponds of Russian plants. Object of the study is the sample obtained from Ural Mining and Metallurgical Company in Russia. The main constituents in flotation tailings are Au, Ag, Cu and Zn with content 1.4 g/t, 12 g/t, 0.66 and 0.5% respectively. The flotation tailings are a refractory material. Gold, as main metal, is fine encapsulated in sulfides, mainly in pyrite. Gold extraction from tailings is 34.0 and 42.7% at P42 and P90 of 0.074mm particle size respectively. In this work heap bioleaching of tailings was studied for oxidation sulfides (pyrite and chalcopyrite) with using mesofilic and moderately termofilic bacteria in acidic solutions. The tailings had low filtration property (< 0.3 m/day) and pelletization was used before bioleaching. Copper containing converter slags flotation tailings and calcium oxide were used as binding material for increasing filtration property of tailings. Copper was extracted in sulfate solution and was precipitated by cementation after cleaning of bacterial solution from iron. Copper recovery was 56.8% at content 61.4% in precipitate. The biooxidation of pyrite was 80%. Cyanidation, leaching with thiourea and heap leaching by cyanide were tested too. Gold extraction from solid bioresidues was 82, 75.3 and 77% respectively. The results of this investigation were recommended for pilot test.

Jan 1, 2014

By A. S. Malicsi, I. Iwasaki

The removal of hydrophobic coatings of flotation collectors from iron ores becomes of interest when a duplex flotation process is considered for upgrading, when a pelletizing process is considered for a concentrate floated with a fatty acid or a soap collector, or when a disposal of froth products from cationic silica flotation is of environmental concern. Ozone can oxidize organic compounds rapidly, thereby removing the hydrophobic coatings of flotation collectors. Ozone is widely used for treating and purifying drinking water, waste water treatment, and for chemicals processing (Murphy and Orr, 1975; Rice et al., 1980). Its uses in metallurgical operations, however, are very sparse (Allegrini et al., 1970; Chernobrov and Rozinoyer, 1975; Ishii et al., 1970; Iwasaki and Malicsi, 1985; Matsubara et al., 1978). Yet, its high reactivity and the absence of potentially hazardous byproducts become of interest in destroying flotation reagents adsorbed on mineral surfaces or remaining in mill water for recycle or for discharge. Duplex Flotation A duplex flotation process, as applied to oxidized iron ores, would involve a fatty acid flotation of iron minerals followed by an amine flotation of the siliceous gangue from the rougher iron concentrate. Such a process has been used in the Florida phosphate fields. Fatty acid coatings cannot be removed as readily with a simple acid or alkali treatment from iron oxide surfaces as from Florida phosphates. A combination of reagents, such as lime and quebracho, lime and alkali phosphate, or sulfuric acid and oxalic acid, has therefore been proposed. In a previous article (Iwasaki et al., 1967) , the use of activated carbon was found to be effective in removing fatty acid coatings both in the duplex flotation and the pelletizing processes. The use of ozone offers another approach to the removal of fatty acid coatings from iron oxide surfaces. To investigate the possible application of the duplex flotation process, a specularite ore from Michigan analyzing 36.5% iron was used. A 600-g (1.3-1b) sample was ground in a laboratory rod mill together with 250 g/t (0.5 lb per st) of sodium silicate to -150 µm (-100 mesh). This was transferred to a Fagergren laboratory flotation cell, and deslimed four times at 20 µm (quartz equivalent). The deslimed pulp was transferred to a laboratory conditioner, diluted to 40% solids, and conditioned with 250 g/t (0.5 lb per st) of soda ash and 250 g/t (0.5 lb per st) of oleic acid. The conditioned pulp was then transferred back to the Fagergren cell, floated until barren of froth, and the rougher froth product was returned to the cell and cleaned. The results are presented in Table 1. The cleaner concentrate at this point analyzed 45.3% Fe. The cleaner concentrate coated with fatty acid was transferred to a 2-L (0.53-gal) beaker. While the pulp was agitated with a glass T-stirrer, ozone was bubbled into the agitated pulp for 15 minutes at a rate of 10 mg/min (0.00035 oz per min) ozone (250 g/t or 0.5 lb per st 03 feed). It was observed that the pulp ceased to froth after about 10 minutes. The amine flotation of siliceous gangue from the ozonated pulp was carried out first by conditioning with a dextrin, a commonly used starch depressant for iron oxides. This was followed by flotation with a stage addition of an ether amine at increments of 100 g/t (0.2 lb per st). Three stages were required to float the siliceous gangue to near completion. The three froth products were combined and cleaned twice. When the cationic flotation Rougher, Cleaner 1 and Cleaner 2 cell products were combined, an iron concentrate analyzing 64.5% iron was obtained at an overall iron recovery of 72.8%. Pelletizing Fatty acid flotation concentrates have been pelletized successfully in northern Michigan mills. But at other locations, fatty acid coatings on iron flotation concentrates proved so undesirable in agglomeration that other methods of concentration had to be sought. For example, a sinter mix containing iron ore concentrates upgraded by fatty acid flotation resulted in decreased productivity. This occurred because the micropellets of particles with the hydrophobic coating are less tolerant of moisture. Thus, the bed permeability is lost (Beebe, 1965). The agglomeration of concentrates obtained by the fatty acid flotation alone, and the hydrophobic coatings destroyed by ozonation or by the duplex flotation process, is not expected to cause any difficulty since the surfaces of the concentrates would be hydrophilic. Removal of the fatty acid coating with activated carbon, indicated by the loss of floatability, was shown to restore the decrepitation temperature of wet balls during drying cycle (Iwasaki et al., 1967). Disposal of Cationic Silica Flotation Froths Recent demands of iron blast furnaces place the silica content of the magnetic taconite pellets at about 5%. Conventional process for magnetic taconite involving fine grinding and magnetic separation often produces magnetic concentrates analyzing in excess of 5% silica. This is due to the presence of the middling grains of siliceous gangue and magnetite. Cationic silica flotation of magnetic taconite concentrates (DeVaney, 1949) may be used to reduce the silica content. But the amine coating on siliceous gangue becomes of environmental concern when the flotation tailings are discarded in tailing ponds.

Jan 1, 1986

By A Kitchen

For the past decade, demand for Australian resources has reached unprecedented levels, thanks mainly to the emerging superpowers of China and India. Meeting demand has meant miners and governments alike have ploughed billions into capital expenditure projects for logistics infrastructure such as roads, rail and ports, to support the ever expanding number of mines and mineral volumes. In more recent times, however, the effect of the global economic crisis has led to a decline in demand for Australian minerals. The downturn has seen companies lay off workers in droves, and delay or cancel expansion projects, in an attempt to preserve cash flow. Whilst the current economic cycle has hit the mining sector hard, it is an opportunity for companies to take stock of their existing operations and plan for the future. As mining companies grapple for scarce capital resources, it is inevitable that industry consolidation will ensue. This presents challenges and opportunities for both buyers and sellers alike, looking to expand operations, or sell off assets to raise cash.

Jan 1, 2009

By C. B. Manula

Simulation continues to hold the spotlight among the Operations Research applications in the operational side of mining. One reason for this is the need to solve the many waiting line and storage problems common to the industry. A second reason for using simulation is the central requirement of retrospect testing. Acceptance of a model by management is more likely to depend on its tested performance rather than on the underlying validity aspects of the model itself. Mathematics have not been and may not be developed that will allow all desired system elements to be considered simultaneously. It is in this realm that simulation bridges the gap between theory and useful design procedures. One of the earliest published accounts of simulation at work in the coal industry is demonstrated by the application cf Monte Carlo methods to explore changes in future operating policies for an existing track system (Manula, 1963). By modifying certain control parameters, revision in design changes were evaluated in the computer rather than in the actual production section. A second application which has found wide use in practice is the VFI-OCR Face Simulator (Prelaz et al., 1968). The model developed here has the purpose of allowing the comparison of methods for room-and-pillar face operations end observing their effect on mining prior to actual installation. Proposed changes are tried in the model and the best of these are selected as a guide for better mire management: IBM&apos;s own simulation package, the System 360 General Purpose Simulator, has experienced heavy use in solving similar problems and other steady-state situations.

Jan 1, 1974

By Paulo Henrique Zunzarrem Pinto

Dois assuntos que vêm sendo cada vez mais discutido na indústria são revisão crítica de projetos e a capacitação da equipe de operação para otimização do processo. Além dos benefícios financeiros diretos que se obtêm na redução do tempo de partida, as melhorias, quando identificadas em fases anteriores do projeto, produzem resultados positivos durante outras fases do ciclo de vida da planta. Neste sentido, o sistema de controle e a capacitação dos operadores desempenham um papel fundamental. O presente trabalho apresenta uma estratégia efetiva de se validar as lógicas de controle de uma planta por meio do simulador dinâmico de processos de alta fidelidade IDEAS, e a utilização desta ferramenta no treinamento operacional via OTS (Operator Training Simulator). Neste trabalho, é realizada uma breve revisão sobre a metodologia utilizada para a construção da arquitetura de automação que permitiu a validação das lógicas de controle e o desenvolvimento do sistema de treinamento. Especificamente, são apresentados resultados obtidos com a simulação em projetos de beneficiamento mineral, por meio da quantificação dos ganhos em operação, manutenção e segurança. Como exemplo de resultados, mais de 2000 pontos de melhoria foram encontrados em projetos executados, e mais de 14 cenários de operação foram criados para treinamento. Os ganhos observados corroboram a robustez da ferramenta utilizada e o potencial da metodologia empregada.

Aug 16, 2017

By Reinhard Bott

The Companhia Mineira de Metais (Brazil) runs a Zn-recovery plant in Tres Marias, federal state Minas Gerais, Brazil. The Zn-production is about 65,000 t/a, This corresponds to a concentrate throughput of about 255,000 t/a with a Zncontent of about 29.5 % at an output of 85 %, The plant is run continuously 360 d/a and 24 h/d, respectively. From this it can be concluded that: Input: approx. 650 - 700 t/d ore-concentrate and approx. 29 t/h ore-concentrate, respectively.

Jan 1, 1990

By K. R. Evans

The yield and fracture characteristics of a Ti-8 pct A1 alloy have been examined at room temperature as a function of exposure temperatures to 1700°F. Em-brittlenzent of the alloy is observed to occur following exposures below 1280°F, the critical temperature for formation of ordered Ti3Al particles. Presence of Ti3Al particles results in an increase in the yield and flout stresses which, for a given exposure time, are a maximum at the critical temperature. Embrittlement is attributed to the occurrence of plastically induced fracture controlled by the increase inflow stress. This interpretation is compatible with the decreasing ductility and increasing crack popagation rates observed with increasing exposure time below the critical temperature. Slip line observations and measurements of the gain size dependence of the yield stress indicate that the slip character of the alloy is not influenced by exposure treatments below the critical temperature. ThE potential usefulness of Ti-A1 alloys in structural applications has prompted considerable interest in studies of their microstructure and mechanical characteristics. The relatively recent surge of interest in the system and at the same time its complexities are indicated by the fact that despite numerous recent efforts14 there has not even been general agreement upon a phase diagram for the system. However, most of the Ti-A1 alloys of commercial interest range in aluminum content from 5.0 to 8.5 wt pct where most investigators achowledge the existence of the ordered Ti41 phase. Goldak and parrs confirmed the existence of Ti41 from X-ray diffraction analysis of the stoichiometric composition while Blackburn6 has determined its presence in commercial Ti-8 pct A1 alloys by electron diffraction analysis and dark field transmission microscopy. The embrittlement of Ti-8 pct A1 alloys was initially reported by Crossley and carew7 who showed that aging in the temperature range of 750" to 1110°F resulted in extreme brittleness. This behavior was later confirmed and correlated by Soltiss to the presence of long-range order in the commercial Ti-8 pct Al-1 pct Mo-1 pct V alloy (Ti-8-1-1) which exhibited anomalous creep and yield strength behavior at 950°F. This investigation was designed to study the mechanical characteristics of a binary Ti-8 pct A1 alloy in order to further examine the nature of the embrittlement behavior reported for the alloy system. EXPERIMENTAL PROCEDURE A Ti-8 pct A1 binary alloy was obtained from the Wah Chang Co. in the form of 0.050 in. sheet. The chemical composition of the alloy is given in Table I. Heat-treatment of the alloy was conducted in evacuated vycor capsules for the tensile sDecimens (1.25 bv 0.25 in. gage section) and in evacuated stainless steel jackets for the crack growth-rate panels. All specimens were annealed at 1700°F for 24 hr and water quenched before an exposure at elevated temperatures. Tensile testing was conducted at room temperature in an Instron testing machine equipped with a pushbutton control for instantaneous control of the cross-head motion. In this manner the change in stress, Aa, accompanying an increase in strain-rate by a factor of 10 was measured immediately after yielding. The crack growth-rate panels used were 3 by 18 in. with a precrack 0.33 in. long cut into the center of the panel. The panels were cycled at a maximum gross stress of 40,000 psi at a maximum to minimum tension stress ratio of 20. Cycling of the specimens was continued until the crack propagated the width of the panels. The crack length was intermittently measured during slow crack growth. EXPERIMENTAL RESULTS Correlation of Embrittlement to the Critical Temperature for Ordering. Blackburn6 has found that the critical temperature, T,, for the formation of Ti41 in a Ti-8 pct A1 alloy with an interstitial content on the order of that given in Table I is approximately 1245°F. The relationship between the ductility of the binary alloy used in this investigation and T, was estimated from tensile tests on specimens which were exposed for 24 hr at various temperatures followed

Jan 1, 1970

By O. Saeki

Dolomite-fluxed pellets have been produced at Kakogawa Works, Kobe Steel, Ltd., since August, 1975. The pellets contain 5.5 % dolomite and have a basicity (CaO/Si02) of 1.3. By charging 30-50 % of dolomite-fluxed pellets into the two large blast furnaces at Kakogawa, a low fuel rate of 450 kg per ton of pellets has been achieved with better furnace permeability and gas utilization. Laboratory studies show that dolomite-fluxed pellets have excellent high temperature properties, and that their softening and melting-down temperatures are about 50°C higher than those of lime-fluxed pellets, and that reducibility at 1250°C is increased from 25 to 70 %.

Jan 1, 1977

By Richard A. Walker, John P. Hager

The thermodynamic properties of the Pb-Au system have been determined between 750" and 1075°C by means of the cell Mo, Pb(1) |(PbO-SiO2){l) , SiO2(s) |Pb-Au(1), Mo The activities of lead and gold exhibit negative deviations from ideal behavior; the values of ? pb and ? the raoultain activity coefficients at infinite dilution, being 0.24 and 0.25, respectively, at 1200°K. The liquidus curve for the gold-rich region of the Pb-Au phase diagram has been determined from measure-ments on seven alloy compositions in the two phase region (liquid + Au(s)). The standard free energies of formation of Au2O(l) and Ag2O (1) have been estimated from cell measurements obtained by replacing the alloy electrode with pure liquid gold and silver. A new integral molar heat of mixing curve for the liquid Pb-Au system is presented and the results of previous studies discussed. The contribution of HM to FE was found to be small relative to TSE. THE use of galvanic cells of the type A(l) |A+Za|A - B(l) [I] provides an accurate means for the thermodynamic study of liquid alloy systems. In Part 1&apos; it was shown that cells of type [I] may be extended to higher temperatures and to a wider range of alloy systems if the ion A+Za is incorporated in an appropriate molten oxide phase, rather than in the classical fused salt electrolyte. In the following investigation the experimental method is extended to an investigation of the thermo-dynamic properties of the Pb-Au system by use of the cell: Mo, Pb(l) | (PbO-SiO2)(l), SiO2(S) |Pb-Au(l), Mo [] Previous measurements on liquid Pb-Au alloys were obtained by Kleppa2 by electromotive force measurements on a galvanic cell involving a molten chloride electrolyte. These measurements were confined to temperatures less than 830°C and compositions with X Pb > 0.2 because of the instability of the cell at higher temperatures. Later measurements by Kleppa3 on the heats of formation in the composition range 0.67 < Xpb < 0.98 were not consistent with the results by electromotive force measurement. The purpose of the present study is to extend the temperature and composition range of the thermodynamic properties and to obtain an independent measure of the integral molar heat of mixing over the entire composition range.

Jan 1, 1970

By E. Sun

Tailings disposal is a significant consideration for the mining industry, with the majority of the ore processed in most mining operations ending up as tailings. Several tailings dam failure accidents have occurred during the past few years and mine tailings dam failures are occurring at relatively high rates. Tailings dam failure is disastrous with the serious damage and the loss of lives. To increase the tailings dam safety, a tailings dam monitoring and pre-alarm system (TDMPAS) based on the internet of things and cloud computing platform has been accomplished with the abilities of real-time monitoring of the saturated line, impounded water level, rain fall and the dam deformations etc. The TDMPAS has been applied in several mines in China and helped the mine engineers monitor the tailings dam safety and get warning information automatically and remotely in any kind of weather conditions. This work has been demonstrated the tailings dam monitoring and pre-alarm system (TDMPAS) is meaningful to monitor the tailings dam physical safety condition. The TDMPAS could be applied to monitor all the national tailings dams online in the future.

Jan 1, 2012

By T. Celik, B. Genc, C. Musingwini

"This paper discusses a new methodology for defining and measuring mine planning software utilization in the South African gold mining sector within an evolving data-set framework. An initial data-set showing the mine planning software providers, their corresponding software solutions, as well as the software capabilities and information on the number of licences was collected and compiled in 2012 in an online database for software utilized in the South African mining industry. Details of the database development and implementation were published in the Journal of the Southern African Institute of Mining and Metallurgyin 2013. In 2014 the data-set was updated with additional and new information. Using the 2012 and 2014 timestamps, a methodology for estimating the software utilization was developed. In this methodology, the three variables of commodity, functionality, and time factor were used to define and measure the software utilization in order to ultimately inform decision-making strategies for optimal software utilization. Using six different functionalities, namely Geological Data Management, Geological Modelling and Resource Estimation, Design and Layout, Scheduling, Financial Valuation, and Optimization, utilization in the gold sector was measured. This paper presents the methodology employed for measuring the mine planning software utilization. The methodology is useful for stakeholders reviewing existing software combinations or intending to purchase new software in the near future and who want to estimate the comparative attractiveness of a certain software package. These stakeholders include mining companies, consulting companies, educational institutions, and software providers. The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand."

Jan 1, 2015

By E. F. Evoy

"The Gunnar uranium deposit was within metasedimentary rocks of the late Archaen Tazin Group. These rocks were intensely altered by albitization so that the immediate host to the ore consisted dominantly of albite, and by the subsequent introduction of calcite. The ore consisted of disseminated pitchblende and uranophane in a pipe-shaped breccia zone. Oxidation of the ore was more intense near surface than at depth, but there was no near-surface enrichment.IntroductionThe Gunnar Mine site is on the tip of Crackingstone Peninsula, on the north shore of Lake Athabasca, Province of Saskatchewan, Canada. The peninsula forms the southern part of the Beaverlodge mining area. The ore consisted of disseminated pitchblende and uranophane in brecciated metasedimentary rocks of the Tazin Group, and the deposit was characterized by extreme albitization and subsequent carbonatization of the host environment.Production from the mine began in 1954 and the ore was depleted by 1963. In that interval the deposit yielded about 5 million tonnes of ore containing about I. 75 kg/tonne U3O8. It was mined initially from an open-pit and subsequently from underground; the open-pit contributed about 55% of total tonnage. Uranium was recovered by atmospheric leaching in sulphuric acid, ion exchange concentration, and precipitation with magnesia.This paper is based on studies made during the productive life of the mine and is concerned primarily with pre-ore alteration of the rocks containing the deposit, and with the ore mineralogy."

Jan 1, 1986

By Morris Cohen, Robert C. Ruhl

The phases in Fe-C alloys over a wide composition range have been studied after splal quenching from the liquid state. Binary alloys containing 0 to 5.1 wt pel C as /cell as a large number of ternary Fe-C-Si alloys with 2.5 to 5.0 wt pct C and 0.3 to 5.1 wt pct Si were attlong those sludied. Olher Fe-C-X alloys, zcilh X being Co, Cr, ,Wn, Ni, and Ru , were also inrestigated after splat quenching. At high carbon contents, a new hcp phase (designaled 6 phase, but different from e carbide) is retained upon splat quenching. The .fraction of this phase varies up lo 97 pcl for a Fe-4.K-1.9% alloy. The composition of the E phase ranges from about 3.8 10 4.8 wt pet C, and the corresponding laltice parameters increase linearly ulith carbon content, while the c/a ratio remains essentially conslc~nl. The E phrtse appears to he a solulion of carbon in E iron, the latler being nornially found only at high pressures. It is deduced that the unit cell of the E phase corresponds to the formula Fe12C3, and llzal il is relaled to tlie ordered slruclures 0.f 6 iron carbide and c iron nilride. The E phase is compared and contrasted to the olher known carbides and nitrides of iron and nickel. An exlrapolaTion of the atomic volume 1,s carhon conlent of /he E pllase lzcts giz.en a neu7 estitnale jor /he alomic volume of E iron, 11.30 cu A, a1 atmospheric pressure and temperature. Other alomic volume relalionships lead to /he co~zpositioti Fe2.iC tor E iron carbide, /he unit cell fortr~ula being -Fe2rClo The E phase undergoes a lulo-slage decomposition upon healing, .forrning firsl rnarlensile plus E carhide, a/ler 1 hr at 140" lo 200°C, slid then ferr ite Plus cementile, after 1 lir a1 330" to 460°C. A1 carbo,l contents between 1.5 and 3.0 LC/ pcl, (he predo.wirzar/t plzase alley quenching is fcc austenite. The retained carbon content of this phase increases with itlcreasing silicon in certain concentration ranges, reaching a maximum of 2.37 wt pct C itz a Fe-2.6C-4.OSi alloy. This is the highest carbon conten1 reLaitled in austenite to date. These high-carbon aus-tenites can be partially tm?zsforttled lo tnartensile hy severe deformation in the temperature range of — 190 to -50°C. TECHNIQUES for splat quenching from the liquid state have been utilized in numerous recent investigations to produce metastable phases in a variety of alloy systems. Among the several ways of splat quenching, the shock-tube method appears to yield the highest cooling rates1-3, 7, 8 and was adopted here. Estimated cooling rates attained in the present experiments ranged from 10&apos; to 10 80Cper sec.&apos; As a part of a research program on interstitial al- loy phases, the Fe-C system was selected for splat-quenching studies. It was hoped that splat quenching would allow high metastable supersaturations of carbon to be retained in solution. Also of considerable interest were the conditions governing the occurrence of the various intermediate phases upon solidification. The alloys investigated included both binary Fe-C compositions as well as six ternary Fe-C-X alloy systems. The known phases in the Fe-C system are summarized in Table I.* Only the ferrite and graphite are ent investigation.14 and is described in detail herein Table II summarizes corresponding data on Fe-N phases, which are also of interest here because of their similarity to the Fe-C phases. EXPERIMENTAL PROCEDURES Alloys were prepared by melting the elements. 99.9 pct purity, in an inert gas nonconsumable electrode arc furnace. The buttons. weighing about 5 g. were remelted twice. were then fragmented. and their interior surfaces were examined for uniformity: if any doubt existed. they were remelted again. Chemical analyses were performed on all the alloys. the accuracy being about k0.05 wt pct. At high temperatures, carbon-containing alloys react with alumina crucibles as follows: If the atmosphere in the splat-quenching furnace does not contain sufficient carbon monoxide the alloy can be depleted of carbon and contaminated with aluminum. Calculations and experimental observations showed that 50 to 100 torr CO partial pressure effectively blocked the above reaction in all the alloys investigated. The splat-quenching equipment in Figs. 1 and 2 provides for evacuation and back-filling with CO-Ar mixtures. The furnace is capable of operation up to 1650°C. and the gettering action of the graphite heating element reduces the oxygen partial pressure in the furnace atmosphere to below 10-5 torr, thus preventing oxidation of the specimens.

Jan 1, 1970

By AIME AIME

HENRY DAYTON WILDE-"Date," informally- manager- of the technical and research department of the Humble Oil & Refining Co., was born at Aguascalientes, Mexico, Sept. 25, 1900. He is a graduate in chemical engineering: M.S. from the University of Texas and I Sc.D. fro111 the Massachusetts Institute of Technology. t For a year and a half in 1926 and 1927 he was a research : associate in the research laboratory of applied chemistry at M.I.T., under W. K. Lewis. In the latter year Dr. Wilde went with the Humble as head of the laboratory experimental division of its refining development department. In 1929 he was made director of production research. Dr. Wilde is the author of important papers in the TRANSACTIONS of the Institute, wherein are also mans dis-

Jan 1, 1938