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"The Midvale. Plant of the United States Smelting, Refining and Mining Company, situated twelve miles south of Salt Lake City, consists of mills for concentrating lead-zinc ores and a custom lead smelter.The milling department includes a 475-ton gravity mill for ores from the United States Mines at Bingham, a 100-ton Huff electrostatic zinc plant and a 60-ton pilot flotation mill for differential separation of lead and zinc. The gravity mill and electro¬static plant are being replaced by a 600-ton differential flotation plant, now under con¬struction, for differential separation of lead, zinc and iron. This new mill will have cap¬acity for treating custom ores in addition to ores from the company's mines at Bingham.The smelting department is equipped to handle 1600 tons of charge per day through six blast furnaces, 48 inches by 160 inches at the tuyeres. All gases from both blast furnaces and roasters are filtered through baghouses, which remove the dust from the gases so effectively that even when the plant is running at full capacity no smoke can be seen coming out of the 450-foot brick stack handling rca2ter gases, nor out of the two shorter steel stacks which take the blast furnace gases. On this account the Midvale plant has come to be known as the ""smokeless smelter.""The blast furnace gases are filtered through 832 woolen bags, 33 feet 6 inches by 18 inches in diameter, and 1200 woolen bags, 28 feet by 12 inches in diameter."

Jan 1, 1925

By A. Hekmat-Ardakan

Conventional hypereutectic Al-Si alloys such as A390 are used principally for the casting of components used in wear applications requiring abrasive resistance such as in engine or compressor blocks. A comprehensive study was undertaken to investigate the potential of improving the mechanical properties of these alloys by the addition of magnesium. A thorough thermodynamic study of the effect of the addition of Mg to the conventional A390 alloy showed that Mg2Si starts to form as a primary phase at 4.2% Mg as well as in the products of the binary and ternary eutectic reactions forming the matrix. Experiments were carried out in producing castings with different cooling and solidification rates of alloys with up to 10% Mg. Mg additions were found to increase the hardness over the as cast alloy due to solid solution strengthening. Also, T6 heat treatment greatly improved the tensile properties of these alloy compositions due to the strengthening effect of the theta-Al2Cu phase. The elongation of these alloys generally decreases marginally with Mg content. The most significant property improvement of the alloys with higher Mg content is the substantial increase in wear resistance. This is attributed to the dispersion of smaller particles of Mg2Si and their coherence with the matrix as compared to the large Si particles in the conventional alloy. A new rheoforming process for A390 is presented that improves the processing of the semi-solid slurry. Structure modification elements were also added to refine the primary and eutectic silicon greatly improving the processing of the semi-solid slurry.

Jan 1, 2011

By J. H. Frye, J. L. Scott, J. W. Woods

THERE are at least two effects of temperature on the stress required to produce plastic flow. 1) Metals plastically strained for the same amount at different temperatures possess different stress-strain curves and different internal structures (e.g., nature and density of imperfections). 2) There is both experimental and theoretical evidence that the stress necessary to produce plastic flow may vary with temperature even though the internal structure remains constant.1-5 Much of the data in the literature is difficult to interpret because these two effects are simultaneously present. In the work reported here, they are considered separately. Standard 0.505 in. tensile specimens were prepared from high-purity Mond nickel and OFHC copper. Nickel specimens were annealed in hydrogen at 1150°C for 30 min and furnace cooled. This produced an average grain diameter of 1.4 mm. Copper specimens were annealed in vacuum at 525°C for 6 hr and furnace cooled. This produced an average grain diameter of 0.11 mm. Nickel tensile specimens were prestrained in tension at 500°K, whereas copper tensile specimens were prestrained in tension at room temperature. All specimens were cooled to 74°K and heated to room temperature. After these treatments all of the tensile specimens of a given set possessed identical structures. All specimens were returned to the tensile machine and tested at various temperatures and constant cross-head speed. Many of the tensile curves showed well defined yields but, in order to minimize personal judgment, the yield was always chosen as the stress corresponding to 0.2 pct plastic deformation. Results are summarized in the graph of yield vs temperature of test, Fig. 1. All of the specimens corresponding to any one line have had identical treatments and, therefore, have identical internal structures. Thus, each line gives the relation between yield stress and temperature for one constant internal structure. The lowest line, which is for annealed nickel, shows no measurable variation of yield with temperature. This is similar to Blewitt's6 results on copper single crystals, but a variation in yield with temperature was found by Andrade and Henderson' in single crystals of nickel, and by Car-recker and Hibbard8 in annealed polycrystalline copper. The three other lines, which are for prestrained materials, show that there is a linear relation between yield stress and temperature when the internal structure remains constant. Such a relation might be expected from a rate equation such as that of Kauzmannl on the assump- tion that the activation energy is either independent of or linear with temperature. These results would also be expected if the shear moduli of copper and nickel are linear functions of temperature for, as Cottrell and Stokes have pointed out," in all dislocation theories of strength the flow stress appears proportional to the shear modulus of the material. In copper and nickel, since the modulus of elasticity decreases roughly linearly with increase in temperature," it is probable that the modulus of shear also decreases approximately linearly with increasing temperature. A detailed discussion of the effect of these and other factors on the temperature dependence of flow stress in face-centered-cubic metals has recently been given by Seeger.4

Jan 1, 1958

By Courtney E. Cleveland

THE gold deposits of the Pioneer and Bralorne mines, in the Bridge River district of British Columbia, are closely associated with a long, narrow intrusive body of extremely variable composition, outcropping on the northeast side of Cadwallader creek and lying almost entirely within the property boundaries of the two companies. Other masses of the same type of intrusive rock are found in the district, more or less along the line of the main axis of the Pioneer-Bralorne in trusive, and have associated with them variable amounts of gold-quartz mineralization (Figure 1). The ore deposits of the district have been the subject of investigation by officers of the Geological Survey of Canada at various times during the past 25 years, and articles on the geology and mines of the district have been published by various individuals in technical journals. A list of the more important re-ports follows: SELECTED BIBLIOGRAPHY

Jan 1, 1938

By Shujian Jia, Mingming Song, Gaoyang Song, Bo Song, Yuhou Yang

An innovative method is investigated to separate inclusion particles from liquid metal by super gravity. To make clear the characteristics of the inclusion separation, Al melt containing MgAl2O4 particles with diameters less than 150 μm has been treated under various super-gravity fields. The thickness of particle-accumulated layer formed at the bottom of the sample and the area fraction, number density and size of inclusions were measured. It is found that the thickness of the particle-accumulated layer decreases and the area fraction of particles at this location increases with the increase of super-gravity field. With the gravity coefficient G=500, time t=2 min, and temperature T=1023 K, it is hardly to find any solid particles in the upper and middle areas of the sample and the separation efficiency is up to 90%.

Jan 1, 2015

By Alcides José de Lucena Silva

O objetivo deste trabalho é demonstrar o desenvolvimento da compensação de sopro no Alto-Forno 3 da CSN durante as manobras dos regeneradores para o ciclo de sopro com o incremento da vazão do ar soprado vindo do moto-soprador. Para a realização deste trabalho utilizou-se a metodologia DMAIC. Na apresentação do resultado final serão demonstrados valores alcançados em torno de 60% de redução da pressão da base do alto-forno com o desenvolvimento e por consequência, um aumento de sua produtividade.

Aug 1, 2018

By J. M. Mutmansky

A number of previous publications have attempted to provide the practicing ventilation engineer with simple guidelines on the optimal velocity to be used in mine openings. Some of these velocities were meant to be used in metal mining operations and some were meant for coal mining. A careful review of these publications reveals that the optimal velocities were determined based upon assumptions that are not existent today. As a result, they are not suitable for use in a modern coal mine. This paper takes a new look at this problem and determines a statistical relationship for optimal velocity that can be applied under both current and future conditions. The analysis performed here is based upon the determination of the optimal velocity for coal mine entries under variations in power cost, mining cost differential, airway friction factor, time value of money, airway lifespan, and quantity of air carried. A total of 8400 different conditions were analyzed for optimal velocity using computer calculation of the capital and operating cost values. Using the individual values of the optimal velocity derived in the calculations, a linear regression equation was fitted to the data to relate the optimal velocity to the other six variables outlined above. This regression relationship allows the ventilation engineer to make an easy, rapid determination of the optimal velocity.

Jan 1, 1984

By Frank M. Howell, Claude E. Schmidt

To counteract the spiralling costs of labor and materials against the fixed sale of its product, namely, gold at $35 per oz, Homestake Mining Co. has revised the milling flowsheet once and effected increases in the daily milling rate twice in the past 12 years. During this period the mining department has been able to hold production costs steady by increased productivity through technical improvements and utilization of the most modern mining by CLAUDE E. SCHMIDT and FRANK M. HOWELL, JR. 46-MINING ENGINEERING, APRIL 1963 equipment. The flowsheet alteration occurred during 1951-1953 when the two crushing plants at the shaft head frames were converted to a three-stage crushing system with the third stage closed circuited to produce a minus 5/8-in. product as rod mill feed.

Jan 4, 1963

By Kelly J. Driscoll

Impure zinc (98.5%) was electrorefined to high purity zinc (99.995%) using a fused salt electrolyte of molar composition 1: 1 : 1 :2 ZnCI2:KCl:NaCl:LiCl with a current efficiency of about 90% at 723 K. A recessed channel electrorefining cell was developed which achieved excellent mixing of both the metal and the electrolyte and by ensuring a very small anode to cathode spacing the voltage drop across the cell was 0.16 V and at a current density of 7kA m-2. The physical characteristics of the cell were observed using a low temperature model which showed the formation of droplets and rivulets which provided mixing. The application of this approach to the refining of other non-ferrous metals is discussed.

Jan 1, 1992

By Nord L. Gale

The discovery of important new ore deposits of lead, zinc, copper and silver in 1955 in Southeastern Missouri has resulted in the development of a thriving mineral industry known as the "New Lead Belt" or "Viburnum Trend", to distinguish it from the older lead producing areas to the East. This region has recently become the world's largest lead producing district with production in 1970 reaching 432,576 tons or 74.4% of the entire United States lead mine production. The area is heavily forested with rolling hills dotted with numerous clear running streams in the Clark National Forest of the Missouri Ozarks. The location is within 70 miles of St. Louis, Missouri and has a natural abundance of water resources which provide an important recreational area for fishing, hunting, camping and other outdoor activities. Until this recent development, the area was sparsely populated and industrialization was almost unknown. The infusion of $150 million in mining capital has brought about a dramatic change in the economic structure of the area and will almost surely be accompanied by changes in its environmental picture. In an effort to maintain this bountiful national resource and to evaluate the changes occurring in surface water quality and aquatic life forms present, an inter- disciplinary research program at the University of Missouri has been undertaken with the support of the National Science Foundation. Research has been carried out to determine background values, establish natural baselines, and to evaluate the extent and causes of changes in streams effected by mine water discharges and wastewater from ore milling operations. The unique topography of the "New Lead Belt" area allows the channelization of milling and smelter wastes to separate stream systems (Figure No. 1) thus allowing measurements of the pollutional effects on an individual basis.

Jan 1, 1973

Mining and metallurgy are more capital intensive than all other industry in Australia. Capital demands are met by domestic and foreign sources of finance for whom the major constraints are the supply of funds and factors of risk and uncertainty. in both mineral development and institutional financing policies, specific options are available to administrators which would allow mining to benefit from a more reliable supply of capital. The strength of major partners involved and overseas participation are important aspects of financing mineral developments. Future changes in financing for the mineral industry are considered most likely in variable interest rate funding, in the leasing of major plant items, and in the development of flexible techniques to ease the burden of infrastructure costs. In a consultancy sense, financiers are available to mining to assist with and to advise on optimal develop- ment of mineral industry projects.

Jan 1, 1975

By G. V. Borquez

For many years drilling and blasting has been considered more of an art than a science. This is still true in some respects, but today scientific approaches to drilling and blasting design must be used to plan an efficient operation which achieves desired fragmentation within constraints. These constraints involve minimizing damage to the wall or nearby permanent structures and avoiding undesirable fragmentation and mine dilution which can adversely affect operation costs. The degree of fragmentation by blasting is the most important single factor in any attempt to optimize the overall cost of the mining operations. The mining cycle begins with the drilling and blasting operations, which result in a given blasted rock size distribution. While this operation represents only about 20% of total mining costs, the efficiency and costs of the subsequent operations are strongly dependent on the fragment distribution obtained.

Jan 1, 1986

By J. G. Asbury

Broadly conceived, the demand for electricity depends upon three sets of variables: (i) the growths of the many individual demands for energy services; (ii) the competitiveness of electrically driven technologies in meeting these demands; and (iii) the energy-conversion efficiencies of installed electrical technologies. The first set of variables establishes the size of the potential market; the second, the market penetration of electrical equipment; and the third, the quantity of electricity required to operate the equipment. All forecasts of electricity consumption ultimately depend upon inferred or assumed relationships to describe the future behavior of these variables. This partitioning of the demand-forecasting problem is conceptually useful and will guide the discussion presented in this paper. However, it is also something of an oversimplification. Examined in more detail, the electricity fore-casting problem is exceedingly complex. The variables mentioned above are, in turn, found to depend upon more fundamental sets of demographic technological, resource, and policy variables. The demand projections developed by the major forecasting services are usually developed in terms of these underlying variables, which themselves must be independently forecast.

Jan 1, 1985

By C. H. Fisher

[Many methods of analyzing tar oils for their tar acid and base content have bun employed in connection with both academic and. industrial investigations. Most of these analytical procedures are based on the diminution in volume caused by extraction with alkali and mineral acids (contraction method), although other methods haves been employed.4/ In many instances the adoption of an analytical method was not preceded by adequate study, and, as a consequence, the literature, on this subject is conspicuous for its contradictory claims and recommendations. It has bin shown in the, case of certain synthetic solutions5/ that large errors may result if the analysis is carried out by simple extraction with alkali and mineral acids.]

Jan 1, 1936

By Calvin K. Lee

This Bureau of Mines report describes a simple fire-retardant treatment for wood. The treatment involves preheating the wood surface at high heat flux (~0.6 cal/cm2 sec) to form an in situ surface char layer (~3 mm thick) on the wood. Laboratory-scale fire tests show that the precharring technique improves the fire-resistance of virgin wood by decreasing and delaying generation of volatile gases through thermal insulation effect of the surface prechar layer.

Jan 1, 1978

By A. B. Kinzel

ALTHOUGH calcium carbide and other compounds of calcium, as well as a number of calcium alloys, are well known and are the basis of important industries in the of United States, calcium metal has been thought of as something of a rarity and has received comparatively little attention from industrial metallurgists. The metal may he made in a number of ways, but the electrolytic deposition of calcium from a molten calcium chloride bath was the first process to be used for its commercial production and is still the standard procedure. Calcium metal has elicited little interest among nonferrous metal producers, as the demand has been relatively small and its production restricted to only a few plants, exclusively in France and Germany.

Jan 1, 1941

By W. Curlook, L. M. Pidgeon

THE PURPOSE of this investigation was to study part of the ternary system Co-Fe-S. Jensen ( 1) established the solubility limits of sulphur in pyrrhotite. The compound with 61.7 per cent Fe, corresponding to a formula Fe12S13, was found to melt congruently at l,192°C. Hulsmann and Weibke(2) determined the Co-S phase diagram from O to 35.2 per cent S. The solubility limits of sulphur in the com-pound Co(l-x)S were not determined. The initial object of the present in-vestigation was to determine the composition at which the compound Coci-xiS melted congruently. Once this was ascertained, it was decided to investigate the ternary system Co-Fe-S from the region of 100 per cent Co(1-x) S to the region of 100 per cent Fe12S13.

Jan 1, 1953

By P. A. Bahri, D. G. Dixon, T. M. Woodward

A comprehensive mathematical model of the Sherritt-Gordon ammoniacal pressure leaching process at K winana Nickel Refinery has been constructed. The process is comprised of six autoclaves functioning as a three-stage leach circuit, operating over the temperature and pressure ranges of 85-95°C and 750-1000 kPa, respectively. The process chemistry forms a complex series-parallel reaction network, characterised by: (1) the gas-liquid mass transfer and reduction of oxygen, (2) the oxidation of eight distinct minerals, (3) the oxidation of sulphur, and successive reactions involving various intermediately oxidised sulphur species, and (4) the oxidation of Fe(II) to Fe(III), and subsequent precipitation as a hydrated ferric oxide. Material balances were developed for species in all three phases, and an energy balance to account for all reactions and phase conversions. The multiple convolution integral (MCI) statistical reactor model was employed for the scale-up of particle kinetics. The model has been validated against plant data, and simulation results are in agreement with plant performance.

Jan 1, 2005

By F. W. Davis

This paper deals in a general way with certain of the necessary requirements of refractories for the open-hearth furnace. The refractories in common use for the different parts are discussed both as to the service they are giving and their suitability to withstand existing chemical, thermal and physical requirements. The relation between the service and allowable cost of a refractory is discussed and suggestions are requested on these points. The purpose of this paper is not to report, to the Institute, the results so far obtained in the survey, by the Bureau of Mines, of the metallurgical requirements for open-hearth refractories, but to present an outline that we hope will serve as a basis for discussion. The systematic survey that the Bureau proposes to make has not been outlined, although considerable preliminary work has been done in the way of interviewing open-hearth superintendents in several of the larger steel plants from the Chicago district eastward. At the several conferences so many of the opinions were diametrically opposite, when considering the same point, that it was thought that such an opportunity as the Institute offers in the way of a clearing house for moot metallurgical topics should not be overlooked. For this reason, the paper has been prepared as a basis for a discussion which, it is believed, will be of value in outlining the program of the Bureau. D. A. LYON, Assistant Director. THE importance of securing suitable refractories for metallurgical operations is daily becoming more universally recognized; particularly in the manufacture of open-hearth steel, where the life and earning power of the furnace depends largely on the judgment and care exercised in the selection of the correct quality of refractory for each of the parts. Any innovation that would make available to the steel manufacturers refractories with longer life or better suited to their needs than those now employed, and at a cost that would permit of their use, would be of enormous value to the industry at large. It is quite probable that revolutionary changes would not be necessary. Material now used in some parts of

Jan 3, 1924

Discussion of the paper Of NOEL CUNNINGHAM, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 601 to 608. C. H. POIRIER, New York, N. Y. (communication to the Secretary*). -Mr. Cunningham's paper, written from the standpoint of a stamp advocate, while commenting more or less favorably upon the installation of ball mills in the Vipond plant, does not, in my opinion, give as much emphasis to the comparatively new departure as the installation of ball mills in the place of stamps justifies. This discussion is based upon my personal and intimate practical work for several years with stamp mills, and for the past three years with Hardinge ball and pebble mills. The fact that the Vipond mine contains about equal quantities of the A and B classes of ore mentioned by Air. Cunningham, and the further fact that I have had a most intimate knowledge of the working of both classes of ore in the Porcupine district in stamp mills and ball mills, justifies upholding my final decision to use ball mills in the place of stamps, and defends my present further action in now increasing the present Vipond capacity by the addition of another 6-ft. Hardinge ball mill, in which action the directors of my company concur. This is one of the strongest evidences I can possibly offer in substantiation of my opinion that the ball mill exceeds the efficiency of the stamp, both in metallurgical and mechanical economy. It is hardly fair to compare a 100-ton per clay plant with a mill handling several times this amount, yet it is my belief that the cost per ton. of grinding in the ball mill is far less than that of any stamp mill in the district, where capacities run up to 400 tons per clay.

Jan 5, 1915