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By E. W. Davis

IF the tonnage of merchantable iron ore remaining in the Lake Superior district is divided by the average of the annual shipments for the past 20 years, it will be found that this ore supply will be exhausted in approximately 35 years. This computed exhaustion period would be an indication of the future activities of the iron-mining industry if it were not for the fact that merchantable ore is being manufactured from low-grade ore, of which there is an almost inexhaustible supply in the Lake Superior district. It is true that at present only the simplest of these low-grade ores are being concentrated to any considerable extent, but progress is being made with the treatment of the more complex ores, and now, in addition to 20 washing plants on the Mesabi Range, three plants are equipped with jigs for the treatment of ore that cannot be concentrated simply by washing. The latest addition to the ore-treating plants of the Mesabi Range is a magnetic roasting and concentration plant at Cooley, Minn., in which ore that cannot be concentrated either by washing or by jigging is roasted to the magnetic state and concentrated on magnetic separators. This plant is beginning its third season of operation, and while it is too soon to make definite predictions, there are strong indica-tions that this new process may make commercially possible the manu-facture of high-grade, merchantable iron ore from large quantities of low-grade ore now considered worthless. After the iron oxide contained in an ore has been converted to mag-netite, almost any desired grade of concentrate can be produced, using magnetic-concentration equipment of the types now in general use for the concentration of the natural magnetites of New York, New Jersey and Pennsylvania. The conversion of hematite (Fe203) to magnetite (Fe304) is easily accomplished by heating the ore to a dull red tempera-ture in a reducing atmosphere. The reaction is slightly endothermic, and while it requires 200 B.t.u. to heat to 900° F. one pound of hematite ore containing 45 per cent Fe, it requires only 100 B.t.u. to convert the oxide into magnetite. In the laboratory, using small quantities of ore, this conversion is very simple, but large furnaces suitable for commercial

Jan 1, 1936

There is a saying, ?If it moves, it vibrates.? This is especially true in our modern industrial environments, where workers use powered tools, machinery, vehicles, and heavy equipment. How workers are affected by these elements of the industrial working environment is a concern of health professionals, govern­ments, and scientists around the world. How to adequately assess the effects of human vibration exposure is an equally important issue. The human body comprises a dynamic structure that is living, intelligent, and complex. Consequently, it is not unreasonable to consider that exposing the body to an array of vibration environments would result in outcomes that are not necessarily simple or easily predictable. Sensations caused by vibration may include nausea, annoyance, discomfort or pain, and exhilaration or pleasure. Many factors contribute to the effects of vibration on humans, including the characteristics of the motion and the exposed indi­vidual, the activities of the exposed individual, and various elements of the environment. There have been attempts to summarize the effects of occupational vibration exposures by simply recommending the avoidance of certain frequencies of vibration or by providing a graphical method, i.e., a single curve displaying all human responses to all frequencies. However, such efforts have not withstood the scrutiny of scientific research and analysis. Thus, attendees and participants at this professional gathering now have the rare opportunity to benefit from the technological advances and new scientific research to enhance their understanding of human responses to vibration that suggest more than a simplistic approach. In the tradition of the First American Conference on Human Vibration (1st ACHV) held in Morgantown, WV, June 2006, the 2nd ACHV provides a forum for scientists, engineers, medical doctors, industrial hygienists, and educators to learn and advance research and education in the specialized area of human body vibration. The conference was organized by the Mechanical and Industrial Engineering Department, University of Illinois at Chicago, with support from the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory. As with the first conference, the 2nd ACHV provides the unique opportunity to learn about the current activities of peers and colleagues and to exchange information on topics of interest such as human response, human modeling, experimental design, sensors, new technologies, and epidemiological studies of human responses to hand-transmitted and whole-body vibration. The conference organizers hope that the publication of these conference proceedings continues to foster new research and technological advances to reduce health hazards associated with occupational vibration exposures.

Jun 1, 2009

On August 22, 1966, just 20 months after writing sales agreements with Japanese steel mills, Hamersley Iron Pty Ltd made its first contractual shipment of 52,000 tons to Yawata Iron and Steel Co Ltd. As world news, the event was not spectacular. But to mining men it represented an astonishing achievement. Twenty months of feverish effort and the expenditure of more than $100 million had created a large open-pit iron ore mine, a crushing plant, storage and load-out facilities for sized ore, and a supporting township at Mt Tom Price; a 182-mile standard gauge railway; and port and loading facilities for a nominal loading capacity of 6000 tph as well as a port town, Dampier, on King Bay. The project was executed in the sparsely inhabited, arid, dissected-plateau country of the Hamersley Range in the northwest sector of Western Australia. Hamersley, 60% owned by Conzinc RioTinto of Australia Pty Ltd and 40% by Kaiser Steel Corp, holds sale contracts for ore and pellets valued at $770 million. The main contracts are with the Japanese, who are to be supplied with 65.5 million tons of ore during the 16 years from August 1966 to August 1982 and 18 million tons of pellets over a 10-yr period beginning in early 1968. Of lesser importance at this time, but presaging trends, are contracts for a total of nearly 1.5 million tons to be shipped to England and Western Europe during the years 1966-68. A pellet plant with a capacity of 2 million tpy is now under construction at Dampier and is to be on stream early next year. Another interesting project for which the plans are set, is a desalination plant for sea water to supply industrial requirements and potable water for the town of Dampier.

Jan 5, 1967

By N. W. Kirshenbaum

"The Marconaflo slurry system was originally developed to reduce costs and solve technical problems in the marine transport of mineral cargoes. In the short time since its inception, it has been found to offer economies and advantages for land-based and in-plant materials handling. This efficient method of reclaiming and slurrying particulate materials at very high pulp densities can be directly utilized in a wide variety of mineral process systems. These include: storage-reclaim applications, where even cohesive, compacted materials can be reclaimed from settled storage ""on demand""; the growing number of hydrometallurgical operations wherein slurried materials are processed to extract or yield metals; certain applications associated with pyrometallurgical treatment; and as a means of augmenting the performance of conventional mineral dressing equipment, such as thickeners.INTRODUCTIONIn the continuing effort to lower costs of producing minerals and extracting metals, the field of handling and transportation often receives too little attention from those engaged in the mining and winning of ores and metals. This comment, which pertains to ferrous and non-ferrous as well as to non-metallic producers, is especially pertinent to products having relatively low value, where transport costs can be a major portion of the delivered selling price to the minerals receiver.One method which was developed recently for the purpose of reducing costs and solving technical problems in marine transport and handling of mineral cargoes is the MARCONAFLO slurry system. A notable feature of this system is its versatility; in addition to its use in marine transport1*, some of its diverse applications have included the mining and reclaiming of tailings2 and in-plant materials handling3. As the concept and fundamentals of this system have been well explained previously4,5, the mechanics of the system will not be elaborated upon here. Rather some specific ways in which MARCONAFLO can be applied to processing and extraction will be explored."

Jan 1, 1973

Calaverite is a gold telluride found in the Kalgoorlie region, Fiji, Cripple Creek Colorado and numerous other locations. It is known that a high pH is necessary for calaverite cyanidation, with the leach rate increasing substantially above pH 12 due to the hydroxide ion concentration. In most circumstances lime is used to achieve high pH, however lime saturates at approximately pH 12, limiting the maximum pH obtainable in a critical region for calaverite leaching. Plant observations, laboratory experiments and thermodynamic modelling show that the maxi-mum hydroxide ion concentration that can be achieved with lime (CaO) is strongly dependent on common ions. The presence of calcium, as commonly found in saline waters, substantially diminishes the maximum pH that can be obtained with lime. Conversely the presence of sulfate ions, as generated through oxidation of sulfides, substantially increases the maximum pH that can be achieved with lime. Sulfide oxidation during cyanide leaching of complex ores may generate acid and sulfate ions, making overdosing with lime at the front of the circuit, or staged addition down the leach train, important to maintaining the maximum hydroxide concentration.

Jan 1, 2014

By Raymond W. Peterson

The practice of Countertrade and all of its variations has increased dramatically during the last five years in great part due to the worsening world economic situation and the Third World's increasing debt problems. Conventional wisdom has held that the goods finding their way into countertrade will tend to be manufactured goods of ever increasing value added. It is my contention that this has not been the case. The continued depression of most metals and minerals prices has conspired to keep a great number of metals and raw materials in the forefront of countertrade negotiations. The concept that if a country needs hard currency it will simply sell metals into world markets for cash has been significantly modified by countertrade which encourages subsidies for raw materials which are in turn funded by higher prices for the manufactured goods which the country must import. Countertrade is a term that is relatively new to most of us who have been involved in the international trade of metals and minerals, but it is one that we will continue to hear more of in the future. Countertrade as it is generally known today had its beginnings after the Second World War in Eastern Europe. As the shattered economies of Europe struggled to right themselves, a "cashless" system of trade developed. This system included such ancient concepts as barter as well as more modern ones like bilateral clearing agreements. For over 30 years countertrade was confined mainly to the COMECON nations and their various trade protocols with Third World nations. If metals and minerals were involved, there was little disruption of world markets by such examples as Cuba shipping ferronickel and sugar cane to the U.S.S.R. for a host of manufactured goods and oil. As the world's economy began to slow in the late 70's and the debt crisis began in earnest in the early 801s, this all began to change. As more and more nations which had previously been almost totally dependent upon their mineral wealth over-extended themselves in an attempt to industralize, they concurrently found their income from minerals falling, due to the decreased demand and subsequently lower prices available in the marketplace. At first these nations attempted to balance their payments by promoting the sales of their high value-added manufactured goods. We have all heard numerous examples of U.S. companies going to sell their high technology products in Rumania or Yugoslavia and being confronted with counterpurchase requirements for machine tools, shoes or drill bits. When faced with these demands, a number of companies chose not to sell into those markets while others merrily signed up the obligations without much intent to carry them out. The Performance Bonds required were generally minimal, especially when considered in light of the high margin inherent in high tech items; and the penalty clauses were equally small or nonexistent. A third group of companies actually tried to buy the machine tools or drill bits either for their own internal use or resale but found that due to poor quality and high prices, they were faced with a difficult if not impossible task. This is not to say that no one was able to fulfill a countertrade requirement, but the success ratio on these transactions was incredibly low. This was one of the major contributing factors to the reputation that countertrade has gained as a discipline ... "that it is mostly talk and very little action." As this situation slowly evolved, both the countries imposing the countertrade obligation and the exporters assuming the obligation began to realize that something

Jan 1, 1986

W. E. RUDER, Schenectady, N. Y. (written discussion?).-To many members of the Institute, papers like this one by Prof. Jeffries, and that on "Reversal of Inheritance" by Prof. Howe, may seem highly academic. Aside from their direct application to all heat-treating processes, to my mind, the establishment of a physical fact and the correlation of facts into a definite law are in themselves ample justification for immense effort. A law, once established, cannot be ignored by those who carry the work along to practical ends. In studying both papers, it seems to me that each author is more concerned with defending a theory than with explaining the individual results as published by various investigators. Take, for example, my sample of pressed electrolytic iron, frequently referred to by both. Prof. Howe, defending inheritance, says that the grains on the second (1300° C.) heating inherited their size from the mother austenite. Prof. Jeffries, defending reversed inheritance, elabor-.

Jan 4, 1918

After reviewing the many excellent papers being delivered here, it is apparent that we are all concerned with the same general subjects of commodity agreements, international cartels, and anti-trust problems as well as the impact of governments on resource management and minerals pricing. Accordingly, as a relative newcomer to the mining business, I feel that my most meaningful contribution can be made by taking a more philosophical look at the future of our system of democratic capitalism. Unfortunately, governments the world over seem intent on jeopardizing the high standards of living resulting from the Industrial Revolution and furthered by the emergence of its by-product, capitalism. This tendency is particularly germane to the basic natural resource field, since government regulations, controls, and intervention in mining far exceed even the constraints normally imposed on hard-pressed consumer-oriented businesses. Increasingly, many governments seem to feel that natural resources no longer belong to private individuals but rather are the property of the state to be developed in a regulated manner and usually in a way directly contrary to the functioning of the free market system.

Jan 1, 1978

By Jian Li, V. Y. Gertsman, David C. Katz, M. Elboujdaini

Analysis of stress corrosion cracking (SCC) usually involves high-end analytical tools including scanning electron microscope (SEM) and analytical transmission electron microscope (TEM). In recent years, focused ion beam microscope (FIB) has found many applications in materials science fields. In this study, high-resolution FIB images have shown details of crack morphology and a plan-view TEM specimen containing the selected crack-tip was successfully prepared. The preparation of cross-sectioned samples containing crack tips was of paramount importance for subsequent TEM analyses.

Jan 1, 2004

By German Zambrana

The solution of the problem of beneficiation of cassiterite from its primary ore deposits is of fundamental importance to Bolivia. The process today involves a gravimetric treatment of the ore followed by sulphide flotation. During the last year, a cassiterite flotation stage has been added in several plants to treat the slime tailings. Although cassiterite flotation is already economical for the slime tailings and the mechanism of the process are understood, it is felt that further research could improve the results. In the past, considerable amount of research and test ark has been performed to select appropriate collectors to improve recovery, to increa¬se the grade of tin in the concentrate, to minimize the effect of metallic ions like Ca+2, Fe+2 and Fe+3 which prevent flotation, and to increase the pH of the pulp which now it can not be higher than 3.0. It has been reported that the halogen salts (1) like NaCl exhibit special surface affinity for cassiterite but none for quartz. These effect seems to be favourable for the selective flotation of cassiterite from silica minerals. In view of these preliminary results it was decided to follow the research accordingly: OBJECTIVES The objectives of the present investigation are: 1. 0 evaluate the influence of NaCl salts in quartz and cassiterite flotation.

Jan 1, 1971

By T. H. Jeffers

The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials such as sphagnum peat moss for extracting metal contaminants from waste waters. The beads, designated as BIO-FIX beads, have removed toxic metals from over 100 waters in laboratory tests. These waters include acid mine drainage (AMD) water from mining sites, metallurgical and chemical industry waste water, and contaminated ground water. Following the laboratory studies, cooperative field tests were conducted to evaluate the metal adsorption properties of the beads in column and low-maintenance circuits, determine bead stability in varied climatic situations, and demonstrate the beads' potential as a viable waste water treatment technique. Field results indicated that BIO-FIX beads readily adsorbed cadmium, lead, and other toxic metals from dilute waters; effluents frequently met drinking water standards and other discharge criteria. The beads exhibited excellent handling characteristics in both column and low-maintenance circuits, and continued to extract metal ions after repeated loading-elution cycles. Based on laboratory and field data, cost evaluations for using BIO-FIX technology to treat two AMD waters were prepared. Operating costs for BIO-FIX treatment, which ranged from $1.40 to $2.30 per 1,000 gal of water treated, were comparable with chemical precipitation costs.

Jan 1, 2010

By James B. Templeton

"IntroductionWith the steady rise of the cost of coal and freight, the time is now ripe for an investigation into the feasibility of using the heat pump for heating purposes in fairly remote industrial areas.The gold mines of northern Ontario seemed to be a most likely place for the application of the heat pump.It was decided that the first step in the investigation would be to determine what economic advantage was to be gained by using the heat pump and thereby determining whether a further and more detailed research programme was warranted.If we can use the heat pump with economic advantage, we can reduce our mining costs and make a worthwhile contribution to our national economy by reducing the import of U. S. coal.The investigation was conducted under the auspices of the Nipissing Fellowship and directed by Professor R. E. Barrett of the Department of Mining Engineering, University of Toronto.With the able guidance of Mr. C. S. Gibson, of the Mines Accident Prevention Association of Ontario, the author visited the following mines: Mcintyre-Porcupine, Delnite, Dome, Lake Shore, Wright-Hargreaves, Kirkland Lake, Macassa, and Kerr Adcliso11.In all cases, the management and technical personnel of these mines were most co-operative and helpful in supplying information and ideas.It should be emphasized at the outset that the design and operation of the heat pump itself is by no means complicated or even new. The reason we hear so much about it today is because there have been improvements in compressors, motors, and heat exchangers in the past few years, and because fuel and freight rates have risen to such a point that, in some cases, the heat pump now has an economic advantage over other methods of heating."

Jan 1, 1950

By Jochen Petersen, Thandazile Moyo

"The oxidative leaching of chalcopyrite in ammoniacal solutions has been evaluated using electro-analytical techniques. The anodic dissolution process has been established to be a seven-electron transfer process under nitrogen in ammonia–ammonium sulphate solutions and ammonia–ammonium carbonate solutions. The number of electrons transferred in the carbonate and sulphate salts suggests that the sulphur is oxidised to a thiosulphate intermediate and the copper and iron released as Cu+ and Fe2+. The Cu+ and Fe2+ is subsequently oxidised in solution in non-Faradaic reactions. The deportment of Fe2+ and S2O32- is affected by choice of the ammonium salt used in the leaching process. In the perchlorate salt, only five electrons are transferred, however observations made on the mineral surface after leaching do not support the formation of elemental sulphur. Scanning electron microscopy and energy-dispersive spectroscopy analysis of the mineral surface suggest presence of an iron–sulphur surface layer completely free of copper under the ammonia–ammonium sulphate conditions, an iron-rich surface layer under ammonia–ammonium perchlorate solutions and absence of surface layer build up under ammonia–ammonium carbonate solutions. INTRODUCTION Hydrometallurgical processes for copper extraction provide a viable route to recover the metal from mixed and low-grade ores, as well as overcome the environmental challenges faced by the traditional pyrometallurgical processes. Chalcopyrite is not only the most abundant of the copper sulphides, but also the most stable, making it recalcitrant to hydrometallurgical processes. Hence, hydrometallurgical processing of chalcopyrite continues to be an attractive area of research due to the vaguely understood surface chemistry of the mineral in different aqueous media. Different approaches to hydrometallurgical treatment of chalcopyrite can be carried out. These include thermal treatment prior to leaching, direct leaching and direct electrochemical leaching (Venkatachalam, 1991). Direct leaching of chalcopyrite can be carried out in various solution systems, as reviewed by Roman and Benner (1973) and Venkatachalam (1991). Ammoniacal solutions are attractive and effective lixiviants that form stable amine complexes with some base-metal cations while rejecting iron. Leaching of chalcopyrite in ammoniacal solutions in the presence of an oxidant is possible due to the stabilisation of copper(I) and copper (II) by ammonia at elevated pH levels. In oxygenated ammonia solutions, it has been suggested that chalcopyrite dissolves according to Equation 1 (Beckstead & Miller, 1977a):"

Jan 1, 2015

By A. A. el-Geassy, A. A. el-Tawil, Hesham M. Ahmed, Bo Bjorkman

The Iron and steel industry is one of the most intensive energy consuming processes. The majority of iron making processes is now directed towards the uses of fossil-based energy sources like coke, coal and oil. Recently, emphasis has been paid to replace part of fossil- based energy sources with renewable biomass-derived reducing agents. In the present work, the possibility of the effective use of woody biomass in carbon-iron oxide composites was investigated. Wood powder was carbonized in N2 atmosphere at 300 up to 450oC. The carbon content in the produced bio-char increased with temperature. The porosity of the char arises from maintaining the cellular structure inherent in wood biomass increases with temperature. The reduction behavior of four iron oxide-bio char composites having different fixed carbon content were carried out non-isothermally up to 1200oC in Ar atmosphere using thermogravimetric anlyser (TGA). Quadruple mass spectroscopy (QMS) was also adopted to measure the CO, CO2 concentrations in the off gases resulted during reduction process. The effect of volatile matter on the reduction of iron oxide was intensively studied. The different phases developed in the reduced product were identified by X-ray diffraction (XRD). The reduction of composites was found to proceed in a stepwise manner (Fe2O3?Fe3O4?FexO?Fe).

Jan 1, 2015

By Amalia Giannakou

This paper utilises 3-D finite-element modeling to study the static and dynamic lateral harmonic response of inclined piles, in a homogenous and a non-homogenous soil, modeled as a linear hysteretic medium. The results of a comprehensive parameter study are presented in the form of dimensionless plots of: (a) static and dynamic swaying and rocking stiffnesses and damping ratios, and (b) distribution of internal forces (bending moment, shear and axial force) with depth. These plots can be readily utilised in practical applications and they offer insight on the role of the inclination in the response of flexible piles.

Jan 1, 2006

By V. G. Papangelakis, G. A. Moldoveanu

The use of anhydrite (AH) seed, control of acidity levels and ageing were assessed as means to promote the conversion of freshly produced metastable gypsum generated in-situ to the less soluble anhydrite phase and force deposition of calcium sulphate on seed as opposed to on equipment as scale, while achieving lower terminal aqueous calcium concentration as well. It was found that moderate sulphuric acid levels (0.25M) and ageing in the presence of AH seed accelerated the gypsum-AH conversion, achieving 100% transformation of the metastable gypsum generated in situ to the more stable, less soluble AH in 6-7 days, while lower/nil acidity did not promote more than 30% AH conversion for 10 days, even in the presence of AH seed. These findings indicate that anhydrite seeding, ageing and incomplete neutralization are beneficial for scale control as well as achieving lower calcium levels, thus rendering the resulting solution more amenable for recycling.

Jan 1, 2015

By James M. Griffin

Ladies and Gentlemen, There have been no less than ten major coal project financings in the last eighteen months. Each of these has been in the order of $100 million to $1 billion for the development of a coal property and its associated infrastructure. It is appropriate at this time to review the nature of these past financings. Why has there been so much activity? There are primarily two reasons. The first is due to the large number of contracts which were signed as a result of OPEC oil shocks. High projections were made for increased coal consumption particularly in world trade. This is distinct from domestic coal mine/power plant projects which often tap a government source of funds. Second is the high cost of coal development in the 1980's compared with a typical company's corporate borrowing capacity.

Jan 1, 1984

By Charles E. Glass

A steadily growing body of evidence indicates that earthquake ground motions can cause failure of rock slopes that are otherwise stable under static loading conditions. As a result, the economic optimum working slope angle is reduced when earthquake shaking is considered in surface mine design, especially in regions of high seismicity. When designing surface mine slopes to withstand seismic motion it is as important to consider the probability of experiencing various levels of ground shaking as it is to consider the characteristics of the ground motion. For most slope designs, simple probabilistic techniques such as extreme value or maximum likelihood techniques are appropriate. These techniques, however, should be applied in such a way that a probability value is assigned to characteristic ground motion parameters at the mine rather than to nearby earthquake magnitudes. Several techniques have been developed to analyze rock slopes subjected to dynamic loads. Most of these techniques do not adequately account for the ground motion parameters of concern. The best technique appears to be one that utilizes actual earthquake time histories. A simple technique that calculates block displacement for any input accelerogram, using a linear acceleration approximation between time steps, has been developed that accurately accounts for rock block response. Results using this technique indicate that the following factors are important for assessing rock slope stability in earthquake regions:

Jan 1, 1983

By Dierling D. H

The paper briefly describes the mining system employed on Western Deep Levels for the past 20 years. The negative aspects which gave rise to a new mechanized method of mining are discussed. The sequence of events leading from the Mine's first attempt at trackless mining in 1980 to the present day in-stope project is presented. The original justification for this project and the in-stope trackless mining method is described in detail. The results to date are evaluated and the original rationale for going in-stope trackless mining questioned. A totally new mining philosophy for Western Deep Levels, whereby major geological disturbances are left in situ and longwalls re-established and mined using trackless mining machinery is described. The economics of this mining method are discussed. Trackless mining machinery can also be put to good use within the conventional longwalls in a new method of mining using Load Haul Dumpers (LHD) in reef drives. When the instope trackless mining project commenced in 1983, it was stated that expansion to any significant degree with diesel powered vehicles could be ruled out and electrically driven alternatives would have to be developed. This issue is discussed and the Mine's decision to expand with diesel powered vehicles explained. Finally, the extent to which trackless mining is likely to be seen in the 1990 s at Western Deep Levels is discussed.

Jan 1, 1986

By A. L. Martikainen

Booster fans increase air pressure to overcome resistance, the objective being to force adequate amounts of air through distant workings. They are used in areas that are difficult or uneconomic to ventilate with main fans alone. Booster fans are currently permitted in underground coal mines in some countries; the United Kingdom, South Africa, Australia and Canada have been defined as major users. Booster fans are not allowed in the US bituminous and lignite coal mining operations at the present time due to safety concerns. This paper presents the history of booster fan use in coal mines of the United States during the last 90 years. Changes in regulations, as well as advantages and disadvantages of booster fan use, are discussed. Research and petitions for booster fan use are highlighted in order to bring the debate into focus.

Jan 1, 2010