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By James F. McDivitt

The mineral industry of today is faced with a number of dilemmas, not the least of which grows out of the series of related facts-world mineral consumption is growing, and is expected to continue to grow; maintaining adequate capacity to meet needs will require very great capital investment over the next decades, investment which must be measured in billions of dollars; much of the new production must come from remote and relatively underdeveloped countries; many of the areas in which such development must take place are not areas in which private capital enters without some trepidation. There are real problems in financing new mineral development-problems which have occupied the thoughts of many in the industry. One group which is currently providing part of the answer, and perhaps pointing the way to further progress in the future, is the World Bank. Loans from the World Bank are arranged usually for countries which are attempting to develop their economies through expanded industrial production. More often than not they are for the development of electric power projects or transportation facilities. Although we consider the mineral industries to be basic factors in industrial development and very important factors in the early stages of development of a country, few of these loans are for mineral development-no more than a half dozen out of a total of well over 300 loans which have been granted to date. Yet the World Bank has played a far more important part in world mineral development than these figures would indicate. The few loans for mineral development which it has made are important, but of considerably greater importance are the secondary effects of many of the non-mineral development loans and some of the special services which the Bank also offers.

Jan 5, 1963

By J. D. Price, W. M. Bertholf

A. C. RICHARDSON*—First of all, [ think that the paper represents a lot more work, study, and correlation than has been indicated by the brief talk by Mr. Price. I like the way he started out and described the areas from which the samples were obtained, the locations of the washing plants, the available tonnages, and other background information with which to evaluate the data he submitted later on. Then I like the way in which he described the various types of washing plants, the tonnages handled and the difficulties of the washing problems; showing the amount of material that lies close to the specific gravity at which the washing separation is made. Later he gave figures from washing plant operations showing recoveries and cleaning efficiencies. He then discussed his own plant at Pueblo. It is the same old plant, I think, that I worked around a good many years ago. It is unusual to find a plant treating nearly 5000 tons of coal a day on tables. But this table plant is, I believe, more efficient than is indicated by the figures that Mr. Price gave. To determine the efficiency of a cleaning operation or to compare it with another it is necessary to consider the quantity and character of the material close to the specific gravity at which the separation is made. It is not fair, I believe, to penalize the table operation by something like 4 pct of out-of-place-material as he has done here. The variety and difficulty of the coals that he has to wash, the continuous shift and change in their composition make a very difficult cleaning problem and the table performance is excellent. I believe that the information in this paper will be of interest and value to anyone operating or planning to build a coal cleaning plant in this or other areas; particularly where the cleaning of fine coal is a problem. The data may be used for comparative purposes in determining the relative efficiencies of other cleaning plant separations. E. D. HAIGLER*—What is a Baum jig? J. D. PRICE (authors' reply)—A Baum-type jig is one in which the pulsations of the water is secured by means of a pulsating air current applied on top of the water. I imagine you are all familiar with the old plunger-type jig which is in effect a U tube in which a plunger on one side of the U, moving up and down, causes a corresponding pulsation on the far side of the jig. In the Baum jig, the pulsating air current is applied on the surface of the water on one side of the U tube of the jig and gives a corresponding pulsation on the other. It is also commonly known as a pneumatic jig. The control of the rise and fall of the water in the jig body proper is under much better control than it is in any of the other type jigs. Mr. Richardson could enlarge on that feature, for I know that he has had considerable experience with these jigs. A. C. RICHARDSON—You have asked how to control a Baum-type jig. The pulsations in a Baum jig can be modified and regulated to a marked degree by the amount of water admitted to the jig and by the adjustments of the valve which regulates the manner in which air is admitted. The number of pulsations per minute is controlled by the number of cycles of the air valve. Thirty to forty cycles per minute is a good speed for large jigs treating coarse sizes of cod. With an air valve it is possible to modify the time-velocity curve of the pulsating water to some extent which in turn determines the action in a jig bed. Within limits the following parts of the air valve cycle may be regulated: (1) the rate and period of air admission, (2) the period of air expansion, (3) the rate and period of air exhaust, and (4) the period of air compression. The rate and period of air admission determines the acceleration of the water at the beginning of the pulsion stroke and the amplitude of the stroke. The period of air expansion, after inlet port is closed, is one in which the water has reached the desired velocity, positive acceleration reduced, and the bed held in a mobile condition. The rate and period of the air exhaust can be adjusted to modify the degree of suction and so modify the manner in which the particles in the bed stratify. The compression period, alter the exhaust port closes and before the intake port opens may be used to advantage in retarding the downward velocity of water during the suction stroke. An ideal jig stroke is one in which during the up stroke the bed is lifted slowly in a mass and opens up like an accordian with the bottom layers dropping away first. With the bed open and mobile the particles adjust themselves according to their hindered settling rates. During the down stroke, while the bed is still open the particles of high specific gravity are accelerated toward the bottom layers. It is possible to approach this stroke with all types of jigs but it is less difficult to approximate it with a Baum jig.

Jan 1, 1950

By H. Majima

In spite of the importance of the presence of pyrite in the flotation of sulphide ores, not many studies have been made from the electrochemical point of view. It is generally recognized that the oxidation of sulphide minerals is one of the most Important factors among those which affect the floatability of sulphide minerals. The concept that the presence of oxygen is essential to the flotation of sulphide minerals is supported by numerous experimental results (1). The presence of oxygen in sulphide minerals- aqueous solution systems would affect the electrochemical behaviour of sulphide minerals and subsequently lead to more complicated reactions on the surface of sulphides. Actually some of the phenomena observed in sulphide flotation are deemed to be more appropriately explained from the electrochemical point of view. The author and co-workers have studied extensively the electrode reactions of pyrite and its significance in sulphide flotation. The results have been partly published elsewhere (2-7). In this paper, the author discusses the electrochemical nature of pyrite, and the three different phenomena observed in pyrite flotation: (1) Xanthate¬dixanthogen system on pyrite, (2) Flotation of complex sulphide ores containing pyrite and (3) Depressive mechanisms of pyrite with cyanide. The phenomenon which has been known as an iron contamination effect due to steel grinding media on sulphide flotation is also explained from the electrochemical aspect. However, this problem is not directly concerned with pyrite, and it will be discussed elsewhere (8).

Jan 1, 1971

By L. C. Galloway, P. M. Tiley

"Some progress has already been made in defining the parameters which will determine the performance of a guidance system in a mine shaft. Very little information is available, however, to help designers or operators predict the effects of varying these parameters in new or existing installations.The experience we have gained from monitoring a variety of installations has led to the development of a model which simulates the motion of a conveyance as it moves through a mineshaft, restrained by fixed guides.This paper presents a general analysis of the performance of the guidance system used in several installations, as well as a detailed description of the problem encountered at one mine and the steps taken to solve it.IntroductionOur company has investigated in some depth the problems that arise in the guidance of mine hoist conveyances.We have a telemetering accelerometer which we obtained to test mine hoist brakes. Frequently, during brake tests, the mine owners request us to use this instrument to measure the lateral motion of the conveyance ""to check guide alignment"". We have made such tests in shafts that have guide s of different kinds, including wooden guides, steel rail s and tubular steel guides. From these tests, we have gained some valuable information about guidance systems.In a well-aligned guidance system that is designed within common and well-known practice, the conveyance will experience very little shock most of the time. However, on rare occasions, shocks up to .5 g will occur. That is, the conveyance exerts a force of up to half its loaded weight on the guide. If the guide slips or is damaged by this force, it will be misaligned for future trips and become the cause of future shocks. In time, the whole guidance system can become misaligned."

Jan 1, 1982

Protect rescue workers fighting fires or mine personnel temporarily working in hot environments from heat stress. Approach A specially designed ice-cooled vest is worn while working in hot environments where cooling the mine air is not possible. How It Works The vest holds a total of 44 individual ice cells in packets that are firmly held near the wearer's skin. These ice cells remove heat from the wearer, reducing heat stress and increasing comfort. The locations of the ice cells and packets are shown in the diagram. The vest is constructed in three layers with the outer layer being aluminzed fiberglass cloth. Its aluminized surface reflects radiated heat, and its fiberglass cloth provides fire resistance and strength.

Jan 1, 1979

By William J. Bronkala

One of the oldest tools used in mineral concentrating is the magnetic separator. Virtually every mineral handling system has need for some type of magnetic equipment in two types of basic usage. 1. Equipment protection through tramp iron removal. 2. Mineral concentration based on magnetic properties of the minerals contained in the ore.

Jan 1, 1969

The world is getting flatter through internet, mobile phone technology, relatively low cost travel, massive outsourcing of manufacturing to China and the transfer of company backroom operations to India. In the iron and steel industry, however, things will remain relatively the same with slow gradual improvements in technology; only the geographic location of plants may change over time. Or will it? The blast furnace smelting process has remained largely unchanged since 1828 when James Neilson came up with the idea of preheated air being delivered to the tuyeres. Likewise, oxygen steelmaking that takes molten iron from such blast furnaces has remained conceptually unchanged since Sir Henry Bessemer invented an air-based system in 1856. These two processes are the core of integrated steel mills that we know today. Typically such mills consist of coke ovens, sinter plant, blast furnace, oxygen steelmaking, continuous caster, rolling mills and metal coating lines. In the intervening 150 years the only real disruptive technology to the integrated steel mill has been the minimill. Based on the use of the electric arc furnace (EAF), in conjunction with a continuous caster and rolling mill, the term minimill is used because steel products are produced at down to one-tenth the scale required for economic operation of an integrated mill, with the EAF producing molten steel using largely scrap steel as its feed, as against transforming coal to coke (coke ovens), iron ore, coke and limestone into molten iron (blast furnace) and molten iron to steel (oxygen steelmaking). There are, however, a number of technologies in development that may cause a paradigm shift in the way steel products are produced and perhaps push the evolution of the minimill as a disruptive technology. Two examples are direct iron smelting, where iron is produced in a matter of seconds by injection of ironmaking feed materials into a molten bath, and thin strip casting, where molten steel is cast into 2 mm strip or less, in similar time. Both have Australian connections. A leading iron smelting technology is the HIsmelt« process, which has its first commercial application at Kwinana, Western Australia, where a joint venture of international parties, consisting of Rio Tinto and the Nucor, Mitsubishi and Shougang corporations, are in the stage of ramping up commercial production. The leading strip casting technology is the Castrip« process that arose from development work done by then BHP Steel, with IHI of Japan, at Port Kembla, New South Wales in the 1990s. Nucor followed this work up, building the first commercial plant for the technology at its Crawfordsville site in Indiana in 2001 and has recently announced an intention to build a second plant in the USA. While both technologies are only into the early stages of commercialisation they are likely to change the face of iron and steelmaking as we know it over the next 20 years. This paper elaborates on the technology of the two processes, why they could change the face of the iron and steel industry forever, what might drive the rapid change and what the changes may look like.

Jan 1, 2006

By H. W. Kilau

The Bureau of Mines evaluated synthetic fluorspars as substitutes for natural fluorspar in basic oxygen steelmaking using a high-temperature rotational viscometer and a quarter-ton basic oxygen furnace (BOF). Consider-able variation in stability and BOF slag fluidizing properties were found when using the initial synthetic products, but improved synthesis methods produced synthetic fluorspars that were generally comparable to natural fluorspar in laboratory testing. Trials in the furnace showed the synthetic products to be operationally the equivalent of natural fluorspar. Higher sulfur and phosphorus contents in some of the synthetic materials did not adversely affect the steel chemistry. Analyses of wet scrubber samples showed evidence that the pelletized synthetic fluorspars experienced greater physical and chemical disintegration than did natural fluorspar. It was also found that operation of a BOF without fluorspar is possible when making low-carbon steels because iron oxide is intrinsically generated as the slag fluidizer.

Jan 1, 1981

By L. G. Austin

Introduction My first contact with industrial milling was during the time I worked in the electricity generating industry in the United Kingdom. In visits to power stations to investigate either deposits in the boiler furnaces or polluting deposits settling around the stacks. I had to check the performance of the vertical coal pulverizers, since poor pulverization aggravated both problems. Naturally, then, when I came to the USA in 1957 to take a PhD in fuel technology at Penn State, I was put to work to review the science of coal pulverization. After this reviewing, I was completely confused. On one hand, there was a well-developed understanding of stress-strain equations, and a rap- idly developing knowledge of how stressed, brittle solids fractured, based on the Griffith crack theory. On the other hand, reading in the grinding literature gave me: • Kick's Law, which was clearly not correct in the light of modern fracture theory; • Rittinger's Law, which was also clearly not correct; • Bond's Third Law of Comminution, which was claimed to have something to do with the Griffith crack theory, but where the connection between the two was made by intuitive pseudo- scientific reasoning I could not accept; • the choice of mill motor power for the most common type of coal mill, the Raymond pulverizer, was calculated from the fan power required to move air through the mill. Although I could accept the empirical connection between the two, it made no sense from the point of view of fracture energy. Even today, most books or review chapters on size reduction start from these laws. incorrect statements abound in the literature, such as “the Hardgrove Index is based on Rittinger's Law," which it is not, "The Bond theory states that work input is proportional to new crack tip length produced in particle breakage," which is not true, etc. My own test work showed that these "laws" did not fit the data for grinding of coal. At about this time, Epstein (1 948) and Broadbent and Callcott (1 956), following the original work by R.L. Brown (1941) at the British Coal Utilization Research Association, proposed describing breakage as a series of fracture stages. I took their concepts and developed the basic differential equation for a batch grinding process continuous in time, analogous to a batch chemical reactor. Robin Gardner then joined the project and did his PhD on treating batch grinding in the same way as a batch chemical reactor. He found that the basic equation had already been partially derived by Sedlatschek and Bass (1 953) in Germany. We confirmed experimentally the validity of the equations for describing batch grinding (1 962) and formulated the equation describing steady-state continuous grinding in a fully-mixed mill. At about the time this work was published, Gaudin and Meloy (1962) and Filippov (1961) independently published essentially the same equations, but without experimental proof of the validity of the concepts. I will give a brief overview of what these beginnings had led to in the design of mills for size and power, and show some of the results of this more detailed understanding of grinding processes. Concepts of Fracture Mills such as tumbling ball, rod, pebble and autogenous mills and vertical mills such as the Raymond, and E-type apply compressive stress to lumps or particles relatively slowly. Compressive stress applied to a particle of an elastic brittle solid imparts overall strain energy to the solid and produces local regions of tensile stress, (Fig. 1) (Berenbaum and Brodie, 1959). Irwin (1949) showed from solution of the stress-strain solutions that a small hole in a region of tensile stress reduces stress concentration at the hole, that is, the tensile stress at the tip of a crack or flaw in a solid is much higher than the general tensile stress in the region. The longer the crack, the higher the stress concentration. Griffith (1920) hypothesized that when the regional tensile stress is large enough, then the chemical bonds at a preexisting crack tip are stretched to breaking point, as illustrated in Fig. 2. When the bonds break, the crack becomes longer, the tensile stress concentration increases, the situation is unstable and a crack opens up (propagates) a surface of tensile stress, creating its own tensile stress at the leading edge. Stored strain energy is converted to the kinetic energy of the moving stress field, which is analogous to sound propagation through the solid, so the crack tip accelerates to velocities approaching those of sound. The moving crack will pass through regions that were previously under regional compressive stress. The equations for "ideal" and "Griffith" strengths are where a is the intermolecular distance, y is Young's modulus, g is the energy

Jan 1, 1998

By W. S. Holt, E. T. Tkac, R. A. Grange

QUANTITATIVE knowledge of the time element involved in austenite transformation in a particular steel provides a sound basis for understanding and planning heat-treatment. Such knowledge is conveniently obtained by measurement of austenite transformation as it occurs at each of a series of temperature levels. The results of these measurements usually are summarized in the form of the now familiar isothermal transformation diagram (I-T diagram, TTT diagram, or S-curve). Although a considerable number of such diagrams already have appeared in the literature, there remain many compositions of commercial importance for which no I-T diagram is available. The diagram for many such steels may be predicted from published data with sufficient accuracy for most practical purposes, but for others no satisfactory prediction can be made because the effect on austenite transformation of one or more of the important alloying elements present is not well enough known. Such a steel is Nitralloy, Type 135-Modified, which, containing about 1.25 per cent aluminum, differs from any whose I-T diagram has been published. This paper presents results of a study of the isothermal transformation behavior of a sample from a commercial heat of this aluminum-chromium-molybdenum steel, together with pertinent supplementary data including the equilibrium transformation temperatures (Ae3 and Ae1), the temperature range of martensite formation, and the end-quench hardenability. These data are directly applicable to the heat-treatment of this type of steel and are of interest in revealing some of the fundamental effects of aluminum as an alloying element in steel. MATERIAL All specimens were prepared from a 13-in. diam bar forged from a 5 by 5-in. billet from a commercial heat made in an electric arc furnace. The composition of the bar was; C, 0.41 per cent: Mn, 0.57: P, 0.016: S, 0.005: Si, 0.24: Ni, 0.17: Cr, i.57: MO, 0.36: Al, 1.26. The forged bar was normalized from 1750°F (955°C) and then tempered for one hour at 1200°F (650°C), this tempering treatment having been given to facilitate the machining of specimens. EQUILIBRIUM TRANSFORMATION TEMPERATURES In hypoeutectoid steel the minimum temperature at which austenite is completely stable, Ae3, and the maximum temperature at which austenite is completely unstable, Ae1, are of great significance in heat-treatment. Since these temperatures are dependent upon com-

Jan 1, 1946

By R. D. Brown

In his April 10, 1978 budget address, Finance Minister Chretien declared that the federal government will restrict the growth of its spending to less than the trend growth of the gross national product; over the past year, both the federal and a number of provincial governments have taken action to cut back on spending policies. This new emphasis in restraint would seem 10 be a response to a mounting public reaction to the rapid growth of government spending - and taxation - over the past 25 years. Although this relatively new government posture on public spending may be admired by many, to others it raises the question: "Can the growth in government spending really be stopped?" This article comments on just how government revenues - and spending - have grown over the past few years in Canada, and mentions some of the issues relating to a slowdown in that growth.

Jan 1, 1978

By F. Sakurai

The enlarged Mitsubishi process in Naoshima has been in steady operation since. May 1991. However, the sulfuric acid plants have been in operation for more than 30 years. The acid plants were modernized between 1999 and 2001 by renewing some of main equipment such as the drying tower and gas heat exchangers, and introducing new technology. At the same time, as an electric energy saving measure, the electric power consumption in the sulfuric acid plant was vastly improved by decreasing the volume of gas treated the installation of low temperature activity catalyst in the 1st pass of the converter and optimization of main gas blower runner. Furthermore, last year, the oxygen plant was replaced and enlarged, and anode production increased from 240,000 to 280,000 tonnes per year with an associated increase of sulfuric acid from 550,000 to 660,000 tonnes per year. This paper describes these recent improvements in the acid plant at Naoshima smelter.

Jan 1, 2002

Several surface coal mining operations in North America are attempting to adapt microprocessor-based monitoring equipment as well as programmable logic controllers onto rotary blasthole drills, towards improving overall drill and blast productivity. These Monitoring While Drilling (MUD) systems permit the recording and processing of important drilling parameters such as rotary speed and torque, instantaneous penetration rate and weight on the bit, and enable the operator ultimately to optimize drill and bit performance. MWD systems on production drills in surface coal mines offer the potential to define mine bench geology in detail and in advance of explosives loading. Recent advance s in explosives and initiation technology will require such a detailed knowledge of ground conditions in order to be fully exploited. Additionally, the logic developed from drill monitoring technology will eventually enable full drill automation through feedback and control, once a more complete understanding of the influences of rock mass characteristics on machine performance is achieved.

Jan 1, 1988

By P. Pal Roy, Ajit Raj Ostwal, M. M. Singh

Field investigations have revealed that sawdust can be used as an efficient additive to ANFO for carrying out production blasts in limestone mines. Sawdust can be used at a reasonably reduced cost without sacrificing fragmentation, muck profile and wall control. Such additives lower the detonation pressure of ANFO by acting as low-grade fuel that reacts or burns more slowly in the presence of ammonium nitrate than does fuel oil. On detonation, it eventually forms near-ideal oxygen balance that helps in liberating maximum energy to break the surrounding rock. It also forms a low-density stable mixture that helps in reducing loading density (kg/m) of explosive in the blasthole. Experiments performed at the Hirmi Limestone mine, M/s L&T, and at the Lambasta Limestone mine, M/s Jaypee Rewa Cements, showed the novel acceptance of the technique in a highly competitive market where cost reduction has been a major area of thrust.

Jan 1, 2003

By Newell G. Alford

Forecasts of future timber consumption in soft-coal mining are handicapped by the lack of adequate experience records for estimating properly the timber requirements of the industry. Data were obtained from plants where records are kept or from operators who collected the information and to these were added composite figures for the continental United States in 1905 and 19191 and for central and western Pennsylvania and for Illinois in 1922.2 The result, representing slightly over 928,000,000 net tons, is shown in Table 1. Some of the companies furnishing data were unable to segregate the timber into classes of use but for those who did, Table 2 shows the board feet of posts and cross ban used per ton of coal mined and the percentage of the total timber consumed that was used in roof support. The wide variation in amounts of timber per ton of coal mined is the result of

Jan 1, 1924

By T. S. Fuller

The tensile properties of steels at elevated temperatures have been studied by numerous investigatorsll primarily for the purpose of determining their suitability for structural uses. Tests with this objective have been confined largely to the temperature range of approximately 20" to 500' C., because of the rapidly decreasing tensile strength at the latter temperature. Tests have also been extended to higher temperatures2 for the purpose of determining the most suitable forging range. This temperature range is also of theoretical interest. The phenomenon if increased tensile strength and decreased ductility .in the so-called "blue-heat" range, approximately 200" to 300" C., is well known. It was suggested to the Bureau early in 1926 that a study of the properties of rail steels in this temperature range might prove of interest in relation to the studies of transverse-fissure failures in rails. There were available from another investigation3 several new rails from several different heats made to approximately the same specification requirements, the complete manufacturing histories of which were known. It was decided to determine, at least in the preliminary series of tests, only the ultimate tensile strength, elongation and reduction of area, because of the difficulty, time and cost involved in determining the proportional limit and yield point at elevated temperatures.

Jan 1, 1930

By T E. Jeffries, M Zentilli, J STguel, C C. Wilkinson, B G. Rusk, V H. Vry

Laser ablation Inductively Coupled Plasma Mass Spectrometry (ICPMS) analysis of fluid inclusions trapping mineralising solutions in major porphyry-copper deposits indicates that copper concentrations can reach 103 - 104 ppm in both dilute, CO2-bearing fluids and in high salinity brines. Non-Cl transport of Cu is implicated. Au has been determined at 0.2 - 0.4 ppm in the low salinity fluids and may be co-transported with Cu. In contrast, high concentrations of Fe, Mn, Zn and Pb are only attained in brines and correlate strongly with Cl-indicating chloride transport. Physical and/or temporal separation of these fluid types can therefore producemetal fractionation within porphyry systems. Evidence concerning the behaviour of Mo is less clear but brine transport appears to be favoured; phase separation is one mechanism that may account for the fractionation of Mo from Cu and the formation of quartz-molybdenite veins. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Adrian Brown

INTRODUCTION The primary tool which is available to improve the stability of an open pit mine at a given slope angle is control of groundwater pressure. This paper sets out the methods by which water pressure control can be achieved in large mines in different materials. The emphasis of this paper is on large mine slopes because. these slopes exhibit the greatest need for groundwater control, the greatest economic benefit from groundwater control, and the greatest technical challenge in achieving groundwater control. STABILIZATION USING MTER PRESSURE CONTROL Groundwater pressures reduce the stability of slopes in two fundamental ways, as shown schematically in Figure 1. In the example, a horizontal failure surface intersects a vertical joint or weak zone. Water pressure acts: o On the base plane to reduce the normal force on the sliding surface and hence reduce frictional resistance to sliding, and o On the vertical back plane, to create a driving force for the system.

Jan 1, 1983

By Alder KF

Nuclear power stations to be installed in Australia will be fuelled from Australian resources of raw materials. This will require the establishment of new manufacturing industries and the eventual expansion of established activities, especially in uranium mining and the preparation of precision metal products. This paper presents some predictions of the possible growth of nuclear power installations in Australia. These might amount to 4000 MWE by 1985 and 11,500 MWE by 1990 and towards the end of the century, about 50% of new generating plant might be nuclear. Predictions are given of the demands for materials (uranium and zirconium) and fuel manufacturing services for four reactor systems which might be considered in the programme. - The availability of raw materials and technical capability place Australia in a particularly good position to undertake the manufacture of nuclear fuel'; in addition to satisfying the domestic demand we should actively seek export markets for these products.

Jan 1, 1970

By Hisahiro Kinoshita, Derek Temple, Yoshio Higashitsuji

The zinc-lead blast furnace process has been installed by two smelters in Japan. In 1966 a unit was commissioned at Harima in Hyogo prefecture by Sumitomo Metal Mining Co. Ltd. and in 1969 a consortium of other Japanese zinc and lead smelters completed their unit at Hachinohe in Aomori prefecture, managed by Mitsui Mining & Smelting Go. Ltd. , the major shareholders. The special characteristics of these two plants are described with particular emphasis on their location and operation. Reference is also made to the processing of a wide range of raw materials, including residues from other processes. Both plants pay scrupulous attention to plant and environmental hygiene to meet the high standards set by the local prefectural governments; the ways in which this has been achieved are discussed. General performance data on each furnace is included, showing that this pyrometallurgical process is supplying 16% of Japan's zinc and refined lead consumption. Note - All tonnes (t) are metric of 2204 lbs.

Jan 1, 1976