Search Documents

By R. Boom

Corus Umuiden, formerly Hoogovens, was the first steel plant in Europe after Voest to introduce oxygen steelmaking. In the decision-making process contacts with Dofasco in Canada about the production of formability steel grades were crucial. In developing oxygen (LD-) steelmaking high liquid steel output rates had to be combined with accurate process control. For ingot casting static models with input control and sampling during interrupted blowing were sufficient to deliver liquid steel within the required carbon, phosphorus, sulphur and temperature windows. Computers were introduced to perform the complicated charge calculations. Continuous casting called for strict control of composition and temperature at process end point and made predictable timing crucial. Dynamic control was introduced based upon sub lance measurements and waste gas analysis. Reliable disposable measurement sensors were developed in a concerted international action. Dissolved oxygen at blow end deteriorated the quality of low carbon aluminium killed steel grades. Blowing gases through the converter bottom improved process kinetics, resulting in lower carbon-oxygen products, yield increase and better phosphorus removal and generated new families of hybrid blowing processes. Introduction of secondary metallurgy facilities such as argon stirring stations, vacuum degassers and ladle furnaces relieved the demands for strict BOF end point control. Desulphurisation of hot metal became standard practice. In regions with scrap shortage hot metal desiliconisation followed by dephosphorisation, was introduced in the blast furnace cast house and hot metal transfer ladles. Later redundant converter vessels were used for pre-treatment, resulting in a two-stage process. The fundamentals of oxygen steelmaking are described and a vision on the future is presented.

Jan 1, 2004

Fast Adsorption Phenomena at Air/Liquid Interfaces

Sep 13, 2010

Volume 2 presents the results of studies of Phelps Dodge Corporation's tailings embankments numbers 1West and 2 West, at Morenci, Ariz. The work involved compilation and description of pertinent factors relating to the physical features and operational characteristics of the facility, including information on embankment construction practices; investigation and research of the general geologic and seismicity characteristics of the site and vicinity; limited field exploration and materials sampling and testing at the site; installation and limited monitoring of piezometers, surface movement markers, and slope indicator casing; limited laboratory testing of materials to evaluate the basic index and engineering properties of the embankment and tailings materials; selected engineering analyses of the embankment for various types of potential "failure" conditions; and includes appendices.

Jan 1, 1974

It has been proven theoretically and experimentally that the use of 10 - 30 per cent DRI in blast furnace along with iron ore or sinter results in lower coke rate and higher productivity. However, to-date this remains unpractised on a regular basis mainly because of economic reasons. The DRI produced by several methods are expensive and difficult to store/handle in large quantities because of its reactive nature and thus DRI in blast furnace remains unacceptable.

Jan 1, 1999

By Tom Treleaven, Andrew Williams

Several contracts were let in Greenwich, Connecticut, for the installation of a sanitary sewer. The majority of the excavation was in rock and involved numerous challenges due to the following conditions:

Jan 1, 2003

By R. W. Smith

Living and killed organisms, particularly microorganisms, and extracellular products derived from the organisms are increasingly finding use in minerals engineering. Goals include both enhancement of mineral processing/11.ydrometallurgica,l operations and remediation of mineral industry wastes. Some of the applications, such as biologically assisted leaching of ?sulfide ores and bioxidation of refractory gold ores, are well established commercial ?processes used around the world. Others, such as the use. of organisms for the removal of heavy metal ions from dilute aqueous streams, are nearing commercial application. Many other uses of microorganisms and. their derivatives are potentially possible. These include use of microorganisms in flocculation or flotation of minerals., remediation of organics potentially discharged from mineral engineering operations, degradation of cyanide, the recovery of bitumen from heavy oil reservoirs and tar sands and the solubilisation of lignites and low rank coals. In order to fully exploit these many possible uses of organisms and their derivatives, extensive fundamental .and .applied research work exploring the fundamentals, potential and practicality of the various possible uses of microorganisms in mineral engineering should be vigorously pursued. ?

Jan 1, 1991

By Michael L. Wayman

Archaeological and ethnographic work during the last century has shown clearly that metals have played a small but important role in prehistoric Arctic cultures. For at least the past several millenia both iron and copper have been used in the North, primarily for blades, projectile points, knives, awls, engraving tools, fishhooks, scrapers and axes. In addition they were used for joining purposes as staples and rivets. It is of great interest to enquire into the origins of these metals. In this connection one begins with the observation that to date there has been no clear evidence for the smelting or melting of metals in the Arctic prior to the arrival of Europeans. This can be explained partly by the absence of traditional pyrotechnologies such as the high-temperature firing of ceramics and the heat treatment of bone and wood. Another factor which surely inhibited the development of smelting/ melting operations is the relative absence of wood in the region. The production of charcoal for smelting requires large quantities of wood, to the extent that the desertification of a number of areas in the Old World is believed by some to have been at least partly caused by charcoal production. In the North this was obviously not possible. Thus the Arctic peoples were restricted to using native (naturally occurring) metals and metals obtained by various direct and indirect forms of contact with areas of the world where smelting was practiced. Both of these sources were important in the case of iron; we know that meteoritic iron, telluric (native) iron and smelted wrought iron were all used in the Arctic. These three types of iron will be considered in tum.

Jan 1, 1999

For many years the scrubbing of roaster gas carrying sulphur dioxide has been carried out at the plant of the Electrolytic Zinc Co. of Australasia Ltd. at Risdon, Tasmania, using long horizontal tubes. in which the gas stream crossed a shower of water. In order to provide for increased roaster capacity, it was evident that additional gas scrubbing capacity would be required to prevent pollution of the atmosphere.This provided an opportunity to review the whole operation of gas scrubbing and an investigation was initiated to determine the characteristics of a counter-current type of scrubber. It was hoped that a change to this type of scrubbing would also reduce the sulphur dioxide concentration of the gas delivered to the atmosphere to a negligible amount. This, paper outlines results obtained from an experimental tower which was operated under a wide range of conditions, the packing height, gas flow, water flow, water temperature, and concentration of S02 in inlet gas being varied independently. A description is given of the leading features and operating characteristics of the plant units, which are designed on the basis of the experimental results. Operation of the new scrubbing system commenced on October 5th, 1948.THE PROBLEMThe gas which is handled carries S02 which may vary in concentration from 2% to 5%, and reaches the scrubbing system at a temperature of approximately 180 deg. C. An appreciable amount of suspended material accompanies the gas which has passed the cyclone system.

Jan 1, 1949

By M. du Plessis, G. More O’Ferrall, A. Hartzenberg

"Lonmin Platinum has experienced several cases of large-scale hangingwall instabilities during the extraction of the Upper Group 2 Chromitite Layer (UG2) at a number of the Marikana operations along the Western Limb of the Bushveld Complex. These instabilities were all attributed to the presence and interaction of prominent geological features and highlighted that assumptions made in the design of the stable pillars and stable span were potentially overly simplistic in these areas. Investigations into the various case studies over the past ten years have resulted in the identification and classification of the rock mass characteristics of the geological structures causing the instabilities.In order to get a better understanding of these instabilities, it is important to understand the structural geology in general, and the sequence of events that led to the formation of the Bushveld Complex in particular. The tectonics involved in the formation of the various layers around the economic mineralized layers has been investigated, and the influence of these tectonic events on the stability of the UG2 stopes hypothesized.Following this investigation, the behaviour of the various layers in the hangingwall of the UG2 is better understood. This paper presents a description of the ground conditions being experienced in the underground stoping environment, the possible source of the associated structures and the resultant behavioural mechanism of these structures causing the rock mass instabilities."

Jan 1, 2015

ALTHOUGH great progress has been made in flotation of the Broken Hill silver-lead-zinc ores, no paper dealing with this subject has been presented to the members of the Institute since James Hebbard's valuable contribution in 1913. Almost every discovery or development in the history of flotation has formed the basis 6f a patent, and but few experimentalists have overlooked the fact that their investigations might lead to the establishment of a patentable process. This, together with the aftermath of patent litigation, naturally resulted in secrecy being maintained in matters appertaining to the art, and the industry as a whole has consequently suffered considerably. Much valuable time has been wasted through numbers ofmen repeating work along certain lines, which, unknown to them, had already been thoroughly exhausted by others, whereas a lot of this would have been avoided by a freer interchange of information amongst those directly concerned. Owing to differences in the ore treated and the various applications of flotation concentration in relation to gravity methods, the flotation problems of the various mines differ considerably. This, together with the secrecy previously referred to, hasresulted in the development of numerous systems and machines, most of which would appear, to the casual observer, to comprise separate and distinct processes. The author has endeavoured to show how much these processes have in common with one another, and, at the same time, has tried to convey some general ideas on flotation to those members of the Institute who are not directly associated with this branch of concentration.

Jan 1, 1919

By E. O. Wagner, A. W. Koth, V. F. Parry, J. B. Goodman, D. C. Gernies

"INTRODUCTION A commercial-scale pilot plant for gasification of lignite was completed by the Bureau of Mines at Grand Forks, N. Dak., early in 1945 as an extension of work on, gasification of low-rank coals initiated in a smaller pilot plant at Golden, Colo., during 1943. The development work on this plant was part of a program to make reducing gases from lignite for beneficiation of low-grade iron ores. The background of this project has been described in a previous report. 6/ The present report describes the major features of the large pilot plant, a record of experimental operating data during five runs totaling about 1,800 hours, .and results of experimental work on the small pilot plant at Golden during 1945.This project has created considerable interest because heretofore there has been little success in several attempts to gasify American lignites.Furthermore, the methed employed is a departure from conventional processes. Natural lignite is fed continuously into an externally heated annular retort and is converted into water gas by heat conducted through alloy metal walls. Because of the high thermal conductivity of metal, the rate of gasification is several times greater than can be obtained when employing refractory walls. The process has been developed to a part that leaves one major question unanswered. - ""How long will the alloy last under practical operating conditions?"" - and this question has aroussed the interest of the Coal Division of the Bureau of Mines in this new development.Owing to the high reactivity of the lower-rank fuels, the water-gas reactions proceed rapidly at medium temperatures of 1,650°F. to 1,800°F. These temperatures can be attained in a reaction zone heated by external means when the temperature of the retort does not exceed 1,900°F. while transferring from 6,000 to 7,000 B.t.u. per hour per square foot. Such rates are several times greater than can be attained through refractory walls as employed in the Didier-Bubaig 7/ and the Ahrens processes. 7/ Therefore, the investment cost of the gas generator per unit of capacity will be considerably lower for the higher-capacity process. However, the maintenance cost of metal vessels will be higher than that of refractory retorts, and this emphasizes the importance of large-scale operation to determine the life of an alloy retort under practical operating. conditions."

Sep 1, 1947

By G. A. Bezuidenhout, S. Bradshaw, W. Malan

"The purpose of the study was to investigate the feasibility of SiC reduction of low-grade concentrates from Lonmin’s Rowland and Easterns operations with respect to metal fall and PGM recovery. These concentrates are rich in SiO2 and MgO with low concentrations of chalcopyrite and Cr2O3. Pd is the most abundant of the PGMs. SiC reduction of samples was conducted at 1600? with 2.5-3.5 kg SiC per 100 kg concentrate.PGM recoveries for Easterns concentrate were better than for Rowland. More than 85% of the Ir and Pd and almost 60% of the Pt were recovered with 3.5 kg SiC per 100 kg concentrate. SEM of slag samples showed little entrainment of metallic prills compared to Rowland samples. This was attributed to the relatively higher melt viscosities of the Rowland concentrate. In order to decrease slag viscosity and to enhance PGM recovery, the FeO content of the Easterns concentrate was increased with the addition of 10 kg converter slag per 100 kg concentrate. Ir and Pd recoveries were increased to about 95%, while Pt recovery was around 70%. On the basis of these results an optimum feed ratio between Easterns and Rowland concentrates and converter slag is proposed. Carbothermic reduction of the optimum charge was also compared to SiC reduction. Carbothermic reduction yielded a marginally higher metal fall; however, the calculated gas emissions and energy requirements were higher than for SiC reduction."

Jan 1, 2015

By Manqiu Xu, Peter Wells, Gord Bacon

"A methodology is proposed for milling flowsheet design using flotation rate, selectivity and residence time distribution data. The flotation rate data and the difference in flotation rates between the main minerals to be separated are determined from laboratory batch tests. The residence time distribution (RTD) data is calculated using the tanks-in-series model assuming each flotation cell is a perfect reactor. The rate, selectivity and RTD data can be used to calculate the optimum flotation cell number in a bank for rougher/scavenger in a commercial plant.This methodology is demonstrated in a case study of a nickel sulfide ore. It is shown that miniplant rougher/scavenger data can be closely predicted from a batch test using the proposed methodology.INTRODUCTIONIt has been the trend in the past several decades that large flotation cells are increasingly used. This is largely driven by the economics as ore grades are getting lower and the rate of ore processing must be increased in order to keep mining operations economically viable. The development and evaluation of 250 to 500 m3 WEMCO SmartCell and Outokumpu TankCell flotation machines are well in progress. There are many advantages in using large cells: fewer cells, less floor space, lower power cost (although this is now being questioned for fine particle flotation), simpler circuit, simpler control, and lower auxiliary equipment cost (Arbiter, 1999). As flotation cells are getting larger, the importance of cell hydrodynamics, namely, air/slurry dispersion, power intensity, froth transfer, residence time distribution (RTD) and short-circuiting are being fully recognized (Jonaitis, 1999; Weber, et al., 1999; Gomez and Finch, 2002). It is not the intention of this paper to discuss flotation cell scale-up. The intention is to answer what is the optimum number and size of cells in a flotation bank for a given throughput. Figure 1 illustrates this problem facing design engineers. The same mean residence time required for a given throughput can be achieved in a single large cell, or many smaller cells in a row. A few cells of large size may be more cost-effective but they may not be as effective as more cells of smaller size in achieving the optimum metallurgy."

Jan 1, 2005

Advanced Jig Separation of Shredded Plastics The authors have reported that the RETAC jig is very useful in separating relatively low density particles such as plastics, and demonstrated that highly efficient jig separation of plastic components in discarded office machines is possible in pilot-scale tests. To further improve the separation efficiency, a hybrid jig (RETAC jig with air bubbler under the particle bed) which can separate plastics having similar specific gravities using differences in wettability produced by a pretreatment, and a reverse jig (modified RETAC jig for plastics lighter than water) were developed. This paper reviews the separation of shredded plastics using advanced jig separation technology (RETAC, hybrid and reverse jigs). Wettability control of the plastics for the advanced jig separation is also reported.

Sep 13, 2010

By John Birkinbine

(Wilkes-Barre Meeting, June, 1911). MODERN advances in practically all lines of industrial development have occurred in such rapid succession, and have been accepted so readily as accomplished facts, that a retrospect surprises us, by showing how comparatively few of the acknowledged factors of improved conditions may be considered as old. While these advances have not been confined to any country, they have been more pronounced in some than in others, and nowhere more so than in the United States, the population of which, having multiplied nearly three-fold between 1870 and 1910, demanded a proportionately greater increase in materials, supplies, and manufactured products. It therefore appears desirable to discuss mainly conditions in the United States, as concrete evidence of industrial progress throughout the world. Looking backward for but three generations, we may trace the introduction and development of canal- and steamboat-navigation; railroad-transportation; artificial illumination beyond that furnished by candles and lard-oil; quick communication by mail, and subsequently by telegraph or telephone; the manufacture of iron, beyond forms of small dimensions; the production and utilization of steel in large quantities; the economic use of mineral fuel, oil and gas, etc. The practical coincidence of the fortieth anniversary and the 100th technical meeting of the American Institute of Mining Engineers, offers temptation to recall and compare the conditions of mining and metallurgy in or about the years 1871 and 1911. A complete resume would cover phenomenal changes in mining-methods and equipment by which the output of individual exploitation has grown from scores to hundreds and even thousands of units in equal time-intervals. Extension of operations in depth and area, demanding machinery of great power

Aug 1, 1911

1. Scope of project In South Australia, the Western Mining Corporation operates the underground copper and uranium mine Olympic Dam. The deposits concerned are enormous (approx. 570 million tons) and have been mined since 1988. At the end of 1996, Western Mining decided to increase the capacity of Olympic Dam from 85,000 t.p.a. to 200,000 t.p.a. Planning At this point, SIEMAG-GHH Mining Division was asked to carry out a study including the planning of the entire shaft hoisting operations and calculation of the investment and operating costs involved. With the assistance of Australian partners, the study was completed within a single month. The principal points of the study were as follows: ? Planning of the hoisting machinery for 1,375 tons per hour from the surge bin below ground to the discharge bunker above ground. ? Optimisation of the hoisting operation with regard to maximum availability and safety. ? Optimisation of the time schedule to minimise the financing costs of the investment. ? Statement of the investment and operating costs. ? Comparison of the technical data, design and availability of the planned machinery with reference plants. Construction of the plant Following acceptance of the study, the decision was taken within a few weeks to implement it. SIEMAG Transplan GmbH received the order to execute the entire shaft hoisting machinery on the basis of the study submitted. The decisive factors in placing the order were: ? Convincing study, adherence to schedule ? Reference to comparable plants elsewhere ? Reference with regard to availability.

May 1, 2003

By N. Fardin, O. Stephansson, L. Jing

A pair of silicon rubber replicas of size 250 mm by 250 mm, from a natural rock joint, was used to produce several high strength concrete fracture replicas of different sizes, from 50 mm by 50 mm to 200 mm by 200 mm. The morphology of the concrete fracture replicas were digitized at the laboratory using a 3D-laser-scanning machine with high accuracy and resolution. The scale dependency of the geometrical properties, including surface roughness and aperture, of the samples were investigated using fractal method. The investigation was extended to study the scale effect on the mechanical properties of the concrete fracture replicas. Four concrete replicas having same geometry from each sampling size were sheared under four different normal loads. The results show that normal and shear stiffness and peak shear strength decrease with increasing sample size and decreasing normal stress. It is concluded that for accurate determination of geometrical and mechanical properties of rock joints in the laboratory and field scales, samples with size equal to or larger than stationarity limit are required. Silikongummiabdrücke der Größe 250 mm x 250 mm einer natürlichen Kluft dienten als Vorlage für mehrere Hochfestbeton Rissreplikas verschiedener Größe. Die Morphologie der Beton Rissreplikas wurde mittels eines 3D-Laserscanners hoher Genauigkeit und Auflösung im Labor digitalisiert. Die Skalenabhängigkeit der geometrischen Eigenschaften, dies inklusive Oberflächenrauhigkeit und Öffnungsweite, wurden mittels Fraktalen bestimmt. Die Studie wurde durch die Untersuchung der mechanischen Eigenschaften der Betonrepliken erweitert. Hierbei wurden vier Betonrepliken der selben Geometrie jeder Probengrösse unter vier verschiedenen normalen Belastungen abgeschert. Die Ergebnisse zeigen das sowohl Normal- und Schersteifigkeit als auch die Spitzenscherfestigkeit mit zunehmender Probengrösse und abnehmender Normalspannung abnehmen. Es hat sich gezeigt, daß für eine genaue Bestimmung der geometrischen und mechanischen Eigenschaften von Felsklüften im Labor und im Feld Proben einer Größe gleich oder größer des stationären Limits verlangt werden. Deux répliques en gomme de silicone d’une fracture naturelle, de dimension 250 mm par 250 mm, ont été utilisées pour produire des répliques en béton de haute résistance de dimensions allant de 50 mm par 50 mm à 200 mm par 200 mm. La morphologie de ces répliques a été digitalisée au laboratoire à l’aide d’un laser-scanner 3D haute résolution et haute précision. L’influence de l’échelle des propriétés géométriques, incluant rugosité et ouverture, a été étudiée en utilisant la méthode des fractales. Des essais complémentaires ont été réalisés afin d’étudier l’effet d’échelle sur les propriétés mécaniques des répliques de fracture en béton. Quatre répliques béton de même géométrie pour les différentes tailles d’échantillons ont été cisaillées sous quatre valeurs de contrainte normale. Les résultats montrent que la rigidité normale et tangentielle ainsi que la résistance de pic diminuent en proportion de l’augmentation de la taille de l’échantillon et de la diminution des contraintes normales. On peut en conclure que, pour une détermination précise des propriétés géométriques et mécaniques des fractures au laboratoire et sur le terrain, des échantillons de taille égale ou supérieure à la limite stationnaire sont nécessaires.

Jan 1, 2003

By A Guinier

RECIPITATION in alloys is undoubtedly one of the most essential phase transformations in metallurgy and, besides, it is a phenomenon of great interest to physicists. It seems then that it can be chosen as a topic for an Annual IMD Lecture. Of course, the subject is a very wide one and I shall discuss here only a very restricted part of it. I should like to show why it is now considered that there is, at the beginning of the process, a stage distinct from the real precipitation, which is the pre-precipitation. We shall be chiefly interested in the atomic structure of the metal in this preprecipi-tation stage. Numerous reviews on this subject have been published recently.', ' The latest was given by H. K. Hardyh t the last meeting of the Institute of Metals in London. One of the most complete articles has been written by the late Dr. Geisler." I should like, at the beginning of this lecture, to pay a tribute to the memory of our friend Arthur Geisler. Some of the ideas which will be developed here are different from those advocated by him. But everybody knows the considerable progress in experiment and in theory which we owe to him and, personally, I deeply feel how fruitful have been the long discussions which we have had during many years. Experimental Basis of the Precipitation Problems Let us recall the essential facts pertaining to the problem of the precipitation. The starting point and the final one are well known. The initial stage is the supersaturated solid solution before quenching. The dissolved atoms replace some of the atoms of the solvent at the points of a definite lattice. It is generally considered that the distribution of the atoms is completely random, and that the lattice distortions are relatively weak. These assumptions are only an approximation. It has now beenproven", that, in some cases, the dissolved atoms have a tendency to segregate to form very small nuclei. These fluctuations of composition are greater than the normal statistical fluctuations in a purely random alloy. We shall see the role played by these nuclei later. The final state is obtained by a very long annealing at such a temperature that an equilibrium is reached in a reasonable time. The alloy is then composed of a matrix which is a saturated solid solution, much poorer than the initial one. Imbedded

Jan 1, 1957

By A Buckley

Many policy issues facing the mining industry and affected communities are at a level of complexity that they can be called ‘wicked’ problems. The term ‘wicked’ in this context is used, not in the sense of iniquity, but rather as social and economic issues highly resistant to resolution. For the resource extraction sector and affected communities there are an array of challenges embedded in the industry’s production and profit paradigm, the remoteness of mineral reserves and affected communities’ expectations of economic benefit and a positive legacy. The mining industry as a whole is dominated by economic, political, legislative and market structures that influence and constrain interactions between mine operations and local communities. For communities, with particular reference to regional Western Australia, intractable problems include the uncertainty of, yet increasing dependence on, a mining economy. Questionable outcomes for local communities include the limited realisation of local employment and business development benefits, and low overall outcomes or low multiplier effects. ‘Wicked’ problems, according to the literature, are best addressed via collaboration. In the mid-west region of WA, with mining and infrastructure construction underway, alliances have formed between mining companies, the major port and rail infrastructure project (Oakajee Port and Rail) and regional and local governance stakeholders. The major impetus for these affiliations is to expedite planning and associated infrastructure development taking into account the lessons from other mineral-led regions. What has resulted is an array of innovative approaches to stubborn problems including planning well in advance of full-scale mining; regionally coordinated procurement; ‘mine ready’ local businesses; and strategic investments in social infrastructure; including community trust funds paid in advance of project delivery. This paper examines these innovative approaches/alliances and assesses their effectiveness in addressing long standing mining/community dilemmas.

Nov 22, 2011

By George C. Stone

WHEN George C. Stone, a Director of the Institute, and so well known to our Members in connection with the Institute's many activities was abroad in 1.919, he secured an interesting collection of these coins, which appeared in Zinc, a publication by the New Jersey Zinc Co. Regarding this collection of coin, Mr. Stone says: "During the war, all gold and most of the silver disappeared, making small change very scarce. As the French Government was fully occupied by the war, it allowed various Chambers of Commerce and other bodies to issue money, both paper and coins. Many of the latter were made of zinc, and I secured several while in Paris. We had all heard of the Belgian and German zinc coins, but I imagine few knew how many different kinds there were. The accompanying plates show both sides of those I got. I took all that the dealer had; but he said that there were a number of others in existence. The coins in the bottom line were issued by the Germans in Belgium during the war and all are still in common use. The first two in the next to the bottom line are German. All of the others were issued by Chambers of Commerce or corporations. A few have been nickel plated; these look and wear much better than the others. "Coins" made of pasteboard were also issued by similar bodies, also notes.

Jan 1, 1920