Search Documents

By P. L. Woolf

Two blast furnaces, one a. commercial furnace and the other the Bureau of Mines experimental furnace, were successfully operated with extremely low slag volumes. The lowest slag rate obtained on the industrial furnace was 335 pounds per ton of metal. Using the same burden materials a 245-pound slag volume was achieved on the furnace. The coke rate saving and increase in productivity resulting from lowered slag rates are discussed as well as the factors limiting a low slag practice.

Jan 1, 1965

By R. L. Grant

The Bureau of Mines developed two new gap-sensitivity methods for explosives, and especially permissible explosives, to overcome certain disadvantages of the present routine half-cartridge method. The revised methods are based on the statistical up-and-down method and give more useful measurements of the 50-percent' gap values than the nonstatistical routine method. The new methods use full cartridges and incorporate certain physical improvements such as the use of cardboard tubes for containing the explosives and coal dust gaps to simulate actual mining conditions. A total of 60 samples of permissible explosives were evaluated simultaneously with the 2 improved methods and with the half-cartridge method

Jan 1, 1967

By M. Kreuh

An investigation of the pressure pulse spectrum generated by the gas dispersion processes in a Peirce Smith copper converter was undertaken via the simultaneous measurement of four tuyeres using high frequency pressure transducers. The data was captured, stored, and analyzed using digital data processing techniques; including power spectral density plots, band-pass filtering, and a principal component analysis (PCA). The process was characterized throughout by a dominant 3 Hz pulse signature attributed to the formation of lateral gas envelopes. In particular, test tuyeres in the tuyere line tended to operate synchronously at the dominant frequency, regardless of operating conditions tested and despite being distributed along the converter. Synchronous behavior is thought to arise from the acoustic coupling and possible resonance behavior of the gas delivery system on the converter.

Jan 1, 2007

By P. E. Walker, M. E. Reed, R. C. Sims, B. Snowdon, D. E. Fallas

An advanced Flash Furnace feed system is the key to improving furnace performance. Clyde-WorleyParsons has developed a revolutionary pulseless pneumatic injection feed system technology, capable of delivering a range of benefits to operators of Flash Furnaces. The solution was created by combining the pneumatic conveying and injection knowledge, expertise and technology of Clyde Materials Handling with WorleyParsons' flash furnace process and operating experience. Optimal furnace burner performance requires the feed material to be presented to the burner as a stable, pulseless and accurately controlled flow, distributed evenly around the burner tip circumference. These simple requirements appear obvious, but are extremely difficult to satisfy in industrial environments and are not achieved by conventional feed systems. Our analysis of existing operating furnaces has identified the link between pulses in concentrate feed rate caused by conventional drag chain conveyors and rapid fluctuations measured in the furnace pressure. These fluctuations occur at a timescale close to the reaction shaft residence time and lead to unwanted instability in the primary furnace reaction zone - the flame. Through the use of the solution created by Clyde-WorleyParsons, it is predicted that the much more accurate control of feed rates achieved can lead to substantial improvements in furnace output, increased oxygen efficiency and better control of the composition of furnace liquids, such as matte, blister or slag. All these improvements lead to significant increases in smelter output and efficiency, and deliver high economic value compared to the cost of the feed system. Clyde-WorleyParsons' solutions can be deployed on greenfield sites or retrofitted, and therefore, have the capability to improve feed control at both new and existing smelters. This paper will discuss the field test work undertaken to date, the impact of findings and the ongoing analysis of linkages between instabilities in the various components of conventional feed systems and furnace pressure stability.

Jan 1, 2007

By G. Clarkson, M. Hitch, R. Clarkson

"A novel reagent-free method of extracting gold from gravity middling concentrates in the Yukon placer fields is presented in this paper. This method exploits the malleability of gold by submitting concentrates to grinding in a rod mill. Brittle waste minerals are effectively reduced, whereas malleable gold particles are flattened and are then extracted by classification through sieves. Recoveries in the field using a laboratory-sized rod mill regularly exceeded 90%, whereas correlation laboratory tests indicated recovery to be most sensitive to the mill charge size. This method has broad potential, including application to the gravity circuits of large hard-rock processing circuits.RÉSUMÉ Cet article présente une nouvelle méthode sans agents réactifs d’extraction de l’or dans les concentrés gravimétriques mixtes que l’on trouve dans les districts placériens du Yukon. Cette méthode exploite la malléabilité de l’or en broyant des concentrés dans un broyeur à barres. Les déchets miniers cassants sont bien réduits, alors que les particules d’or malléables sont écrasées puis extraites par classification au travers de cribles. Si les récupérations sur le site à l’aide d’un broyeur à barres de laboratoire excèdent 90 %, les essais de concordance en laboratoire indiquent que la récupération est très sensible à la taille de la charge du broyeur. Cette méthode présente un grand potentiel, notamment une application possible aux circuits gravimétriques des grands circuits de traitement des roches dures.INTRODUCTIONExploiting the high density of gold to separate it from waste materials is the oldest known mineral processing technique. This basic technique is still widely used in gravity concentration circuits today; however, gravity processing invariably results in high-value middlings, especially in the Yukon placer gold fields. In addition to having a uniquely high density, gold is also the most malleable metal. This unique malleability can be exploited to extract gold from otherwise inaccessible gravity middlings.The Yukon placer gold industry has been continuously ongoing since the 1860s, and today produces approximately 60,000 oz t (1.87 million grams) of crude gold annually, most of which is from the Klondike region near Dawson City (Van Loon & Bond, 2014). It is important to note that Yukon placer miners do not use any chemical extraction methods; rather, gravity upgrading methods are the sole processing techniques used. Placer deposits are typically coarse, well liberated, and naturally gravity concentrated and recoverable, thus making more expensive chemical extraction unnecessary (Mitchell, Evans, & Styles, 1997). Furthermore, a strict permitting regime, environmental concerns, lack of expertise, and fear of repercussions from regulators prevent miners from attempting more advanced processing methods, such as flotation or cyanidation. Even simple chemical extractions like mercury amalgamation have not been implemented for decades, with one observer noting that, as many as 30 years ago, “the art of mercury for amalgamating appear[ed] to be dying [in the Yukon]” (Osler, 1983)."

Jan 1, 2017

By A. Warczok, C. M. Diaz, A. Bergman, T. Utigard, M. Barati

The world wide consumption of energy is steadily increasing and by 2030 it is forecasted to grow by another 50%, leading to mounting political and economic pressures. For any pyrometallurgical operation, it is therefore paramount to investigate and implement methods to decrease the use of energy. In the pyrometallurgical processing of steel, copper, nickel and other high temperature metals, a large amount of energy is lost in hot off-gases, molten slags, mattes and molten metals. Most of this energy is generally lost during the cooling and solidification steps with very little focus on energy recovery or reuse. In this paper we will quantify how much energy is contained in the various slag streams, then review previous attempts and methods employed to recover some of this energy, and finally evaluate some novel technologies that could potentially be employed.

Jan 1, 2011

By M R. Hettigner, J Nawrocki, C E. Johnson, P G. Cahill

This study evaluates the effects of both short inter-hole and intra-hole delay times on rock fragmentation and throw. Full-scale test blasts were analyzed at a granite quarry in Talbotton, GA. This analysis provides a representative understanding of timing effects on fragmentation in the field, different from previous lab scale studies that negate the effect of geology. Inter-hole delay times between 0 ms and 25 ms were tested on a series of 4 bench blasts and subsequently examined using photographic fragmentation analysis methods.

Jan 1, 2017

By T. K. Akopyan, E. A. Naumova, V. V. Doroshenko, N. A. Belov

"A qualitative and quantitative analysis of the new Al-Ca-Mn-Fe phase diagram in the region of the aluminium corner is carried out using both thermodynamic calculations and experimental methods. Using the obtained data, the principal possibility of creating both cast and wrought sparingly alloyed aluminium alloys with calcium, manganese, scandium and zirconium at allowable iron contents of up to 0.4% that do not require solution treatment and quenching is justified. At the selected concentrations, the entire amount of manganese (1%) is practically included in the aluminium matrix, while calcium (~2%) and iron are in the multiphase eutectic, which has a fine structure. The joint introduction of 0.25% Zr and 0.1% Sc into the alloy leads to precipitation hardening due to the formation of the L12-Al3(Zr,Sc) phase during annealing. Based on the experimental data for the model multicomponent Al2CaMnFeZrSc alloy, it is shown that such alloys can combine high mechanical properties and good manufacturability during both casting and metal forming. This is due to the combination of a narrow temperature range of solidification with a fine eutectic structure.INTRODUCTION Hardening in branded aluminium alloys (both cast and wrought) is generally achieved by heat treatment of the T6 type, including quenching and artificial aging (Zolotorevskiy, 2007; Kaufman, 2004; Mondolfo, 1976). Heat treatment significantly increases the cost of the final products. Therefore, industrial companies are interested in developing alloys that can be hardened to the desired level without quenching. To solve this problem, alloys with scandium are the most suitable (Toropova, 1998; RØyset, 2005). This element (usually in an amount of ~0.3%) is one of the most effective hardeners in aluminium alloys, due to the formation of Al3Sc (L12) phase secondary precipitates, the size of which is less than 10 nm (Knipling, 2010; Fuller, 2005). These nanoparticles are formed during the annealing via decomposition of the supersaturated aluminium solid solution (hereinafter referred to as (Al)). This feature allows us to significantly increase the strength of aluminium alloys by simple annealing (at ~300°C), i.e., without heat treatment, including quenching. However, scandium is a very expensive metal, so its use as an additive is severely limited. The most effective method is the introduction of scandium together with zirconium (Lefebvre, 2009; Booth-Morrison, 2012). The optimal combination is the introduction of ~0.1% Sc together with 0.20–0.25% Zr, which, according to (Belov, 2006), gives approximately the same strengthening effect as the introduction of 0.3% Sc."

Jan 1, 2018

By Y. Luo

"It is generally known that spontaneous combustion potential is a function of coal rank, with low-rank coals having high susceptibility to self-ignition and high-rank coals having low potential. To establish this functional relationship and use it as an engineering tool to identify the propensity of coal to self-heat, both rank and spontaneous combustion potential should be quantified. ASTM D388 is normally used to classify coals by rank, but this classification system can only serve a qualitative analysis. To classify coals by their potential for spontaneous combustion, the self-heating temperature (SHT) method originally developed by the U.S. Bureau of Mines (USBM) was used by Litton and Page (1994) to correlate coal rank with spontaneous combustion potential. In that method, the SHTs of coal determined by an adiabatic experiment are linked with proximate analysis results through a proposed concept known as the “moist fuel ratio.” This ratio is a function of moisture, volatile matter and fixed carbon, all of which have widely different content percentages in different ranks of coal and have strong relationships with coal rank. However, the method is highly empirical, and there is large standard deviation between experimental data and calculated results. The equation correlating the coal quality parameters to determine SHT should be improved with more experimental data.This paper reports on the development of a new system for predicting the spontaneous combustion potential of U.S. coals, based on coal composition data from the U.S. Geological Survey’s coal quality database. First, the user is provided with a quantified classification of coal rank. Second, based on experimental SHT data covering a wide range of ranks from lignite to low-volatile bituminous coal, the original USBM correlation for predicting SHT is improved for the respective rank of coal. The relationship between the rank and SHT of U.S. coals was developed and plotted. The plot diagram can be used for a quick estimate of the SHT of a U.S. coal and as a cost-effective tool for the initial risk assessment of a new mine development."

Jan 1, 2015

By Z. B. Karshigina, Ye. G. Bochevskaya, E. A. Sargelova, Z. S. Abisheva

At the present time of depletion of reserves of high grade rare earth deposits, it has become necessary to involve low grade raw materials in the production. Among the rare-earth deposits in Kazakhstan, the most advanced one is Kundybai. The mineralogical composition of ore is represented by the minerals: a-quartz SiO2, kaolinite Al2(Si2O5)(OH)4, muscovite KAl2(AlSi3)O10(OH, F)2, albite Na(AlSi3O8), rutile TiO2, and hematite Fe2O3. It contains: 59.1–68.5% SiO2, 19.1–28.4% Al2O3, 7.2–10.3% Fe2O3, 0.51–0.84% TiO2, 0.10–2.32% CaO, 0.39–2.10% MgO, and some other elements. Rare earths are located in the clay part (kaolinite, goethite) in the ion-adsorbing form, and they are represented by the main ore mineral churchite - YPO4·2H2O. In the ore the amount of rare-earth elements (total REEs) varies from 210 to 600 ppm. Elements of the cerium group predominate (La, Nd, Ce, Sm, Pr) and the yttrium group is represented by Y, Gd and Dy. Extremely thin intergrowth and accumulation of REEs in clay minerals cause difficulties in their recovery using flotation and gravitation beneficiating methods. The purpose of this work is the development of an extraction method for the main mineral components of ore with transfer of the total REEs into the solution with high extractive efficiency. Results of the experimental work into high-temperature processing (hereinafter referred to as sulphatization) of ore by sulphuric acid with subsequent dual-mode water leaching of the sulphate product (sinter) are presented in this manuscript. The influence on the ore sulphatization process of some physical and chemical parameters: liquid-to-solid (L/S) ratio (0.36–0.86 cm3/g), temperature (100 – 500°?), concentration of sulphuric acid (3.0–18.62 mol/L) and duration (0.5–2.5 h) was studied. Optimal technological parameters of the process were determined to be: L/S ratio 0.36–0.46 cm3/g; temperature 500°?; concentration of H2SO4 9.0 mol/L; soaking time 1.5 h. Under these conditions it is possible to obtain extractions of ~ 85% REE, as well as 58% aluminium and 10% iron. XRD and IR-spectroscopy analyses were used to determine the material constitution of sulphated cakes obtained under optimal conditions. It was found that the primary minerals are quartz and muscovite; however different sodium aluminium silicates and albite minerals are present as well. In the future, it is proposed that the leach residue cakes are processed into precipitated silica (“white soot”).

Jan 1, 2016

By Ralph M. Foecking

The disposal of the phosphate slimes produced by Florida beneficiation operations is perhaps the biggest single problem of the phosphate mining industry. This is an old problem which has not been solved and which is becoming increasingly severe. In a typical phosphate mining operation, the phosphate rock mined is initmately mixed with sand and clay, constituting what is known as matrix. During the beneficiation, the clay and other fine materials are separated usually at -150 mesh, and washed from the phosphate rock in a form of diluted slurry known as phosphate slimes. The quantity of slimes solids and their composition vary considerably with the location but usually represent from 25 to 35% of the ore mined. Because of the affinity that clays have for water, large volumes of water are required to separate the granular material in the matrix forming a dilute slime suspension (1.5 to 3% solids) of colloidal material, which settles very slowly, and thus requires immense impounding areas, which never becomes totally usable land. These ponds also contain about 25 to 35% of the total P205 values mined. The magnitude of the problem represented by the slimes can be appreciated better if we realize that there are around

Jan 1, 1971

?It is not the strongest of the species that survives, nor the most intelligent. It is the one that is most adaptable to change.? Charles Darwin. Canada?s mining and exploration companies have evolved over the past century from essentially a pick-and-shovel industry to a high-tech industrial sector. This evolution has occurred in fits and starts, and has been driven by the shifting environment of economic, technical and social opportunities and pressures in Canada. As labour costs have gone up, and labour availability has gone down, the industry has evolved more efficient processes. As mineral prices have increased or fallen, the industry has evolved either by expanding or shrinking production, or by changing processes to adapt to the newly prevailing conditions. As stringent environmental protection legislation has been implemented, the industry has adapted accordingly, and has substantially changed its mindset to incorporate sustainability into its way of doing business. These changes have occurred over a number of decades, and have usually occurred as the industry?s reluctant response to pressures it couldn?t evade. This model mirrors the classical paradigm of natural selection where evolution is driven by pressures external to the organism (or organization) ? change occurs to the degree necessary for survival and prosperity, but generally no further. In recent years a new paradigm has started to come into play in Canadian mining and exploration. Rather than only a reactive response to the external economic, social and technical factors, groups within the mining community are becoming proactive in developing strategies for future adaptive change. Instead of each against the other, they are developing more sophisticated paradigms where they can both compete against (such as in marketing) and cooperate with (such as for tech development) their fellow organizations. Most importantly, they are seeing individual and national advantage in a collaborative Canadian approach to address the advantages of overseas competitors who often have lower labour costs, lesser environmental standards, or more accessible markets and transportation. This has translated into large-scale mining community support for the Canada Mining Innovation Council, and its programs in exploration, mining, processing, HR development, energy and environmental stewardship. This new paradigm is adaptive to the current environment but is substantially different from the older way of doing business in two major ways ? it is based on a collaborative approach to competitive advantage, and it is highly proactive rather than reactive. All the programs have their priorities determined principally by the mining and exploration companies, whose first obligation is to determine the long-term research priorities of the industry as a whole, rather than for their individual companies. Only after industry consensus on priorities does the research community become engaged in the implementation of specific projects to address those identified priorities. A goal of the program is to effectively create a virtual mining research laboratory, by engaging all the major research centres in the country. This approach is being actively adopted by much of the Canadian mining community, and argues well for the adaptability and long-term survival of mining in Canada.

Aug 1, 2013

By A. D. Walters

"IntroductionScreens are used in coal preparation plants for four basic functions, namely:I. Scalping off large size run-of-mine coal for initial size reduction;2. Sizing of coal treatment in different process streams;3. Removal of magnetite (dense medium) from clean coal and refuse;4. Dewatering.Canadian coal preparation plants use screens extensively in the above functions. Even plants where no beneficiation takes place, screening and crushing are carried out in the size reduction process.Description of Process UnitsThe type of screen used in coal preparation plants generally falls into the following categories:Fixed Screens and Grizzlies (for large coal)Often a simple rugged construction, either set horizontally above a bin or inclined with the coal flow.Fixed Sieves (for fine coal)They are used for dewatering and/ or size separation of slurried coal or discard. The sieve bend, the Vor-Siv, the Wilmot riffle and the cross flow screen fall into this category. The most commonly used in coal preparation plants is the sieve bend, Figure 1. Coal slurry is fed tangentially onto a fixed curve wedge wire screen deck. The solids are separated at a predetermined particle size, delivering a partially dewatered overproduct and a dilute underflow. The coal slurry is initially delivered to the sieve bend via a feed box. A series of baffles spreads the feed evenly across the width of the deck. The slurry drops from the last baffle, passes through the feed spout and is fed tangentially to the screen. It is important that the feed should contact the surface immediately at the front end of the sieve bend. It is possible to lose as much as 250Jo of screening area with a poorly fitted screen box.The full stream of coal slurry flowing over the sieve bend decreases in depth, in increments of approximately •;4 the slot width each time it passes a slot. Sieve bends make a size separation at 112 to 2h the slot width. This feature virtually eliminates blinding of the screen surface. Slot sizes are normally quoted in millimetres, available standard slot sizes are from 2 mm to 0.125 mm. The sieve bend is also widely used in coal preparation for preliminary dewatering."

Jan 1, 1989

By K. C. Dean

The combination of flotation and chemical processing methods presented in this report of the Bureau of Mines enabled treatment of typical low-grade ferberite ores from the Boulder County, Colo. area, to produce specification-grade synthetic scheelite. The overall recovery from ore to synthetic scheelite was 87 percent, based on a flotation recovery of 93 percent and a similar recovery in chemical processing. Preliminary mineral dressing studies revealed that the physical and mineralogical nature of typical ferberite ores precluded high recovery of tungsten in plus 60-percent-W03-grade products by these methods. Therefore, the flotation research was focused on attaining plus 90-percent recovery in a concentrate containing 10 percent W03. Detailed studies were made (1) to establish optimum grinding conditions for obtaining adequate mineral liberation, (2) to develop collecting and modifying reagent combinations that would enable controllable selective flotation, and (3) to define the influence of different pulp solids, temperature, pH, and time for conditioning and for the rougher and cleaner flotation stages.

Jan 1, 1961

By J. Dubbert, T. H. Jones

"This paper describes a rib-control methodology that uses standing support to provide most of the lateral resistance to the rib. The method is analyzed, and its boundary conditions for rib control are described. In this method, an animal-fencing mesh product covers 80 percent of the rib surface and is sparsely bolted to the rib. Can supports or other similar stiff supports are installed primarily as roof support for the entry. As the rib spalls and dilates, the mesh catches the material and expands, pressing against the standing support. Mining proceeds, and vertical roof loads increase the normal force on the Can supports, causing friction at the top and bottom of the support to go up, thereby improving lateral resistance to rib swelling.At one mine in the western United States, this method has proved excellent at preventing the buildup of rib spall. It substantially reduces the number of bolts used for screen installation, improves installation efficiency, reduces manual labor and provides more rib coverage than many screening methods. Because standing support is typically part of the roof-control plan in longwall tailgates, no additional standing-support costs are incurred. IntroductionRib safety in underground coal mines is an oft-studied topic because ribs are high-hazard areas. An overview of early rib safety research can be found in Jones and Mohammed (2014). There is a significant difference between rib support and rib control. Support improves safety through the installation of strengthening elements, such as bolts and dowels, designed to reduce rib spalling. Although spall reduction is preferred, controlling how the rib fails is enough to ensure safety in some situations. Rib control uses external elements to provide confinement, thereby holding sloughed material in place, or to prevent falling rib material from striking mine personnel. This paper presents a study of a control method used on the pillar side of a longwall coal mine tailgate in the western United States."

Jan 1, 2015

By D Finn, D Kentwell

Experience has shown that the E-Type multiple indicator kriging (MIK) estimation technique often works well for resource estimation in stockwork mineralisation that contains a mixture of high and low-grade mineralisation types that are difficult or impossible to separate spatially. E-Type MIK, like ordinary kriging (OK) is a smoothing estimator and where data is sparse can result in estimates of grade tonnage curves that do not reflect the true block variability at selective mining unit (SMU) scale. The rank and replace (RR) estimation methodology is designed to reproduce both local block accuracy and true block variability at SMU scale and has shown good results when used with highly skewed unimodal diffusive style mineralisation. This paper examines the use of RR with mosaic style mineralisation typically found in stockworks via a case study using real data from Newcrest’s Telfer West Dome deposit. Resource level estimation results for ordinary kriging (OK), E-Type MIK and RR are compared to close spaced grade control models as the reference reality.Results show that stationarity requirements and declustering can severely impact on the usefulness of the rank and replace technique and that it should only be used where trends are not too strong and data are relatively uniformly spaced. This does not rule out its application to stockwork or mosaic style deposits. However, in this case, the presence of trends and different data densities requires the non-stationary domain to be further broken down into sub domains for the RR technique to be effective.CITATION:Kentwell, D and Finn, D, 2017. Testing new estimation techniques – rank and replace: a stockwork case study, in Proceedings Tenth International Mining Geology Conference 2017, pp 365–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Travis Davidsavor, David Provost

A segment of high-pressure steel petroleum pipeline needed to be replaced on a hillside and beneath a waterway within an existing right-of-way containing multiple petroleum pipelines. The pipeline replacement required excavation of sedimentary rock to allow placement of the new pipe. As a result of an existing right-of-way limitation, steep slopes, and hard rock, blasting would be required as close as 7.8 meters (25 feet) from two operating pipelines. Existing pipeline company standards would have effectively precluded the construction of the replacement pipe by blasting rock. To facilitate the required construction and evaluate actual pipe stress during blasting to ensure pipeline integrity, a comprehensive evaluation methodology was developed by a team of pipeline, mechanical, geotechnical, instrumentation, and blasting engineers. A total of 60 strain gages were affixed to the steel pipe and seismographs were buried at the surface near the blasting area. Test blasting allowed pipe stresses with corresponding ground motion to be monitored. A conservative analysis approach evaluated individual peak strains and revealed that only small pipeline strains, and therefore stresses, were induced in the pipeline as a result of blasting. This evaluation allowed specific procedures to be developed to inform the blasting operation of maximum explosive loading and minimum charge distances. Additionally, this effort provided the pipeline operator with appropriate pipeline operating pressures during blasting activities to limit total stresses in the pipeline to be below allowable stresses imposed by code, regulators, and company operational limitations. Recommendations were developed to measure the blast generated ground vibrations with seismographs buried at the depth of the pipe, near the pipe, and limit the ground vibrations from blasting to 150 mm/s (6 in/s). If ground vibration intensities of 120 mm/s (4 in/s) or more were observed, additional engineering review is recommended. Finally, all blasting would be suspended and all activities reviewed at peak ground vibration intensities of 230 mm/s (9 in/s). The evaluation effort resulted in effective and efficient construction of the pipeline replacement and allowed the pipeline operator to better understand blasting induced stresses on their assets.

By Louis M. Perlman

CAN PRESENT TRENDS CONTINUE? Can population growth in the world keep going at the average rates of the last few decades, till, say, the year 2000? And beyond? At the same time, can we expect steady increases in mineral consumption per head, all over the world, as the living standards of many nations converge toward the living standards of North America? If they do converge? Does the total fund of world resources extend, with foreseeable techniques, to supplying the consequent demands for metals, non-metallic minerals and energy? Do we have the requisite economic and scientific techniques available to answer these questions? Certainly, we cannot forecast over decades with any certainty. There are many, of course, who seem to believe that by the simple fitting of trends, they can tell us something about the world and resource constraints in the year 2000, twenty-three years from now. It is significant that many studies of this sort have added sustenance to the 'doom-watching' fraternity of commentators. The reason is simple. The extrapolation of exponential trends into the distant future frequently leads to the most astounding and impossible scenarios. Another feature of exponential growth is the suddenness with which certain fixed limits are approached. It took world population two hundreds years to increase by 1/2 a billion, from 1650 to 1850. Yet some U.N. estimates suggest that the net addition to human population will be over 2 billion between now and the end of the century. Thus, the present world population would increase from a little under four thousand million today to rather over six thousand million in the year 2000.

Jan 1, 1977

By T. Shi, Q. Yuan, S. P. Vanka, B. G. Thomas

"The quality of continuous cast steel is greatly affected by fluid flow in the mold region, especially involving transient phenomena. Mathematical models are being applied to investigate many different aspects of these phenomena, but their accuracy must be validated before they can be applied with confidence. As part of a long-term effort to develop and apply comprehensive models of the continuous casting process, this work evaluates the relative accuracy of models of three different fluid flow phenomena in continuous casting through comparison with measurements.Firstly, transient flow simulations of velocities in the mold region are compared with digital particle image velocimetry (PIV) measurements in a single phase water model. Large-eddy simulations (LES) are found to reasonably match the flow measurements, including transient flow variations, except at long time scales, which could not be modeled owing to the excessive computation costs. The standard K-e model produced very good agreement with time-averaged velocities for relatively little computation time, although it is inaccurate at predicting the transient variations. Secondly, particle trajectory calculations are compared with water model measurements to study the distribution and flotation removal of inclusion particles. The LES model was able to match the measurements both qualitatively and quantitatively. Thirdly, steady, multi phase flow computations are compared with flow patterns observed in both a water model and an operating steel caster with argon gas injection. For the same conditions, the water model and steel caster produced very different flow behavior. The computational model was able to match the measured flow patterns in both cases.This work suggests that computational flow modeling has the potential to match real processes as well or better than water models, especially when complex related phenomena such as particle motion and multiphase flow are involved. Much work is still needed to further improve the models and to apply them in parametric studies."

Jan 1, 2001

By R. B. Nourse, S. F. Gwynn-Jones, S. Nikolic, M. L. Bakker, I. McDougall, H. Joubert

"Tenova Pyromet’s core furnace knowhow and expertise has been built within the ferroalloy and nickel/platinum group metal (PGM) industries with the supply of electric furnaces for a number of nickel/PGM operators, including Eastplats, Lonmin, and Anglo-Platinum in South Africa, Mineraçào Serra Da Fortaleza in Brazil, and Norilsk Nickel in Russia. Tenova Pyromet has also supplied the electrode columns and associated electrode equipment – the heart of the electric furnace technology – for cobalt recovery in furnaces in Zambia and the Democratic Republic of the Congo. The quantity and size of projects undertaken by Tenova Pyromet has provided the opportunity to continuously improve furnace designs and the scope of supply, culminating in the most recent nickel/PGM project currently under construction at Northam Platinum. Through this innovative culture, the Tenova Pyromet Base Metals Initiative was formed in 2015 to develop the Novasmelt™ Furnace; a next generation optimised Top Submerged Lance (TSL) furnace design. The combination of Tenova Pyromet’s advanced Novasmelt™ product with our industry leading electric furnace technology are discussed with reference to applications for nickel and cobalt production. Flowsheet arrangements are compared summarising potential capital savings, operating requirements and achievement of downstream product quality.INTRODUCTION Tenova Pyromet is a leading player in the field of smelting technology development and equipment supply. Tenova Pyromet is the result of the union of three furnace suppliers under the Tenova banner: Techint Technologies (Tagliaferri), Core Furnace Systems Corp (Lectromelt) and Pyromet Technologies. The furnace experience of the combined groups dates back over a century with the earliest Lectromelt going into production in the early 1900s. Throughout the modern era, Tenova Pyromet has developed a reputation for providing dependable innovative smelting technology, high quality equipment and sound project execution to a worldwide client base with customer plants operating in Europe, Southern Africa, North America, South America, Russia, Kazakhstan, the Middle East, South Korea, and India. Tenova Pyromet’s core knowledge and expertise was developed in the South African ferroalloy, base metals, and platinum group metals (PGM) smelting industries. Tenova Pyromet has spent considerable effort on development and has contributed significantly to improve the state of the smelting industry. Tenova Pyromet’s electrode columns have become widely renowned and are now providing significant benefits, especially in increased furnace availability, to many smelting furnace operators. The electrode column is the heart of the furnace as it delivers a controlled amount of electrical energy, at an optimum depth in the burden/bath, to the smelting process. Every furnace is custom designed to the specific operating range and optimal operating point of that furnace and process"

Jan 1, 2017