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By H. M. St. John, T. Rynalski, G. K. Eggleston

Maintaining a satisfactory structure in brass and bronze castings has always been a foundry problem of great practical importance. While metallurgists and scientific investigators have not entirely ignored this matter, it has received less of their attention than has been given to iron, steel and the wrought copper and aluminum alloys. Investigation in this field has probably been discouraged to some extent by the complicated nature of the alloys involved. Hundreds of alloys are in more or less common use, most of them containing copper, zinc, lead and tin in widely varying proportions. They also contain appreciable percentages of iron and antimony as impurities, and often phosphorus, which has been added as a deoxidizer and fluidifier. Small amounts of sulfur are usually present. It is not uncommon to find nickel, sometimes in rather substantial quantities. Traces of other metals are frequently present. So complicated and variable a mixture obviously offers difficulties in any investigation of the various factors that influence the structure and other properties of the casting. Incipient Shrinkage Bolton and Weigandl have called attention to a type of structure characterized by intercrystalline fissures and large dendritic crystals which are frequently tarnished to an orange or reddish brown color. This intercrystalline porosity they term "incipient shrinkage" and attribute to the presence of carbon monoxide in the atmosphere under which the metal was melted. The defective structure to which Bolton and Weigand refer has become a brass-foundry problem of major importance, because it occurs with distressing frequency in leaded brasses and bronzes when these are melted in a neutral or reducing atmosphere. Since the electric furnaces, now coming into general use in brass foundries, normally operate with such an atmosphere and, in fact, depend upon it in part

Jan 1, 1930

By C. D. Demond

IN reverberatory smelting, fuel is the chief item of expense, as it commonly is in processes using large percentages of it. Hence the most suitable supply is eagerly sought; that is, the supply which, in the end, yields the greatest net profit. The better grades are not infrequently bought, even at an advanced price, because they are apt to be decidedly more economical. High price, of itself, however, is no merit, for freight is generally the largest part of the cost of fuel, and the nearby supply may yield as high efficiency as that from a greater distance. If a poorer grade is reasonably good, and if its cost is low enough to more than offset the decreased technical efficiency, it is of course the more suitable. Any smelting, operation depends for both efficiency and economy on raising the furnace atmosphere considerably above the "critical" temperature; that is, above the temperature at which smelting is completed. If this temperature is not exceeded, smelting stops, no matter how much coal is burned; and the real value of a fuel depends on the number of degrees that the temperature is continuously kept above this point. For example, if one fuel maintains 2,500° F. and another only 2,100° F., while the "critical" temperature is 2,000° F., the first is worth at least five times as much as the second, although the increase above atmospheric temperature is only one-fifth more in one case than in the other. This "margin of temperature" above the smelting point is much more significant than the total number of heat units developed from the fuel. The case is parallel to that of water flowing from a pipe. The reservoir may contain a billion gallons of water; but, even though the fluid has come to the nozzle, not a drop will run out, where it can be of practical use, unless the level in the reservoir is higher than the nozzle; and the speed and volume of flow depend on how much higher the level is in the reservoir than at this point. If the temperature inn a furnace is not above the critical level there will be no slag to flow over the skimming plate, even though there are enough heat units to bring an unlimited quantity of charge up to the point of slag formation; and just as the value of a water supply for the purpose of putting out a fire depends largely on the effective head, so the difficulties of furnace management

Jan 8, 1914

Jan 1, 1902

By H. H. Kellogg

Available high-fernperatzwe equilibrium measurements and other thermochernical data have been critically reciewed for sulfation reactions of the type: Recommended values for log K and ?Fo as junctions of temperature are given for thirty-six suck reactions involving twenty-six different metals. Methods of calculation and choice between conflict-ing data are discussed. SELECTIVE sulfation now enjoys a considerable renaissance as a metallurgical unit process due, in large part, to the available of the fluid-bed re- actor—a device capable of the close control of temperature and gas composition necessary for a successful sulfation process. An additional need, however, if sulfation chemistry is to be approached in a scientific manner, is a reliable body of data on the equilibrium and kinetics of sulfation reactions in simple and complex systems. This paper offers a critical review and compilation of equilibrium data on pure sulfates (simple systems). The last such review, by K. K. Kelley in 1935:30 has proven itself most useful, but the existence of many new data makes necessary a re-evaluation of the available information. METHODS OF CALCULATION For a simple sulfation reaction such as MS04(c) = MO(c) + SO3 [1] there are two approaches one may take toward establishing the value of ?Fo or K as a function of

Jan 1, 1964

By V. J. Sikora, T. S. Hutchinson

This paper presents a method for making a water-rlrive ana1gsis without prior knowledge of aquifer geometry and uniformity using a standard desk calculator. Although it is necessary to know the initial oil in place to use this method, this is a minor limitation to the scope of (he method since in most reservoirs it is possible to obtain reasonably accurate volumetric oil-in-place estimates. An equation is developed which relates pressure at the water-oil contact to the water influx rate as a function of time by a factor called the resistance function. The resistance function introduces the composite effect of the aquifer geometry and flow resistance disrribution. It is pointed out that the characteristic shape of this function makes it possible to start with on approximation of the function and successively improve the approximation until the correct resistance function curve is obtained. In this fashion water-drive estimates can be made without the limitation of assuming simplifed aquifer shapes and flow distributions. This is the novel feature of this development. Methods are given for extrapolating the final curve to calculate future aquifer behavior. Equations are developed for adjusting the pressures and water influx rates where it appears that possible errors in these quantities make it difficult or impossible to obtain a useuble resistance function curve without this adjustment. Application of the pressure build-up analysis techiiique to estimate. some of the aquifer properties is also presented INTRODUCTION A great many oil pools are the result of oil accumulation in some type of trap in an otherwise large and continuous porous stratum. The void space of this stratum outside of the oil pool itself is filled with water or brine. In analyzing performance of the oil pool surrounded by this water aquifer, it is quite necessary. in most cases, to include behavior of the water. When the pressure at any point in a fluid system is lowered, such as by opening a well in an oil sand, fluids in the immediate neighborhood of this point will begin flowing towards this lower pressure sink. As pressure in this area drops due to flow towards the sink, fluids from farther out will start to flow towards the lower pressure. As more and more fluid is removed from the system, the distance from the sink or well within which flow is occurring will continually increase; that is, thc region of disturbance will grow. If some rigid boundary such as a fault is reached by the disturbance, this area will cease to grow; but if some movable boundary is reached, such as a water-oil contact, the area will grow on out into the water, although rate of growth may and almost always does change. The relation between amount of pressure drop and amount of fluid flowing at any point and at any time in an aquifer depends on such factors as compressibility and viscosity of the fluids, the porosity and permeability of the rock, geometry of the whole system and withdrawal rate or pressure drop. With these factors known, it is theoretically possible to calculate the pressure-flow behavior of the system, However, in practice true solutions to the problem are next to impossible due to complexity of reservoir systems. A number of approximate methods of solution have been developed based on various simplifying assumptions. One frequent assumption is that the water-oil contact can be located and equations defining oil reservoir and aquifer solved separately by assigning values to various parameters so as to match past pressure and production history. Usually the properties of the aquifer are not known, since few, if any, wells are drilled through the aquifer; but the water influx and the pressure at the reservoir boundary are known over some time. If it can now be assumed that the aquifer is circular, pie-shaped, or linear, and that it has uniform properties, it is possible to fit a theoretical dimensionless curve to the past aquifer performance history and therefore calculate future water drive. These theoretical curves are available in the literature,1,2,3 Of course, the assumption of uniform aquifer properties is almost always somewhat in error. Fortunately, however, moderate variations from the average have little effect on behavior of the system; and, hence, the best fit of a theoretical curve is frequently satisfactory. In other cases variations in aquifer properties and geometry are large enough that none of the available theoretical curves will give an acceptable fit of the data. In these cases, methods of fitting the data with various electrical analyzers have been developed.1,2' It is the purpose of this paper to present an approach

By Charles Wraith

THE property of the Roan Antelope Copper Mines, Ltd., is situated at Luanshya, north-central part of Northern Rhodesia, and is connected with the main line of the Rhodesia Railways, Ltd., by a 24-mile branch line from N'dola. Most of the material and supplies that are not available in Africa are shipped into the country via Beira, on the East Coast of Africa, a distance of 1473 miles from Luanshya and the nearest ocean port. The output of copper is shipped by rail to Beira and thence by boat to the market. Passenger travel is mostly via Cape Town, a distance of 2162 miles from Luanshya. Excellent passenger trains operate on regular schedules between Cape Town and Northern Rhodesia. Luanshya is 13° south of the equator at an elevation of 4000 ft. above sea level, and has a mild healthful climate. During the rainy season, from October to March, the rainfall averages 53 in. The area is pro-fusely covered with vegetation. An ample supply of water for industrial and domestic purposes is available throughout the year. The more important supplies for smelting purposes, such as wood, coal, limestone, silica, quartzite, and clay for "dolly" mud, are con-veniently available. Excellent grades of coal, coke and firebrick are obtained from the Wankie Colliery Co., Ltd., Southern Rhodesia. The Wankie colliery has just completed the erection of equipment for the manufacture of silica brick. An ample supply of quartzite of good grade is available for this purpose. Silica brick is also obtained from the Belgian Congo and from India. Limestone is quarried from a large deposit a few miles from Bwana Mkubwa, which is 30 miles by rail from the smelter. An abundant supply of clay for "dolly" mud and for lining launders is available within a short distance of the smelter.

Jan 1, 1933

By Robert F. Mehl

THE gamma-alpha transformation in iron and iron-rich alloys is of such practical and theoretical importance that many papers have been published upon the subject relating to critical temperatures, transforma-tion rates and accompanying property changes. Although crystallo-graphic studies are of less immediate practical usefulness, the opportunities which these offer to furnish data, on the basic atomic movements which characterize the transformation are not to be neglected1. The early work on the crystallography of this transformation has been reviewed in the fourth paper of this series2 since then several important papers have appeared. Our present, knowledge may be briefly summarized as follows. Kurdjumow and Sachs, working with a 1.4 per cent carbon steel3, established the orientation relationships subsisting between the face-cen-tered gamma and the metastable tetragonal lattices in freshly quenched martensite, and between the face-centered gamma and the body-Centered alpha lattices in tampered martensite. The orientation relationship observed in the latter case may be stated in terms of planes and directions observed to lie parallel in the two lattices: { 111 }Y//{110}a [110]Y//[111]a

Jan 1, 1937

By Roy R. Weil, John A. Dziubek

This paper discusses the use of computer modeling, data manipulation, and mapping of three multi-seam coal properties in the Appalachian coal basin. Each case history represents a slightly different application of computer usage for estimation of reserves and planning surface mine sequencing. This practical use of computers demonstrates the suitability of data processing for normal evaluation of coal properties.

Jan 1, 1983

If problems are opportunities in disguise, the mining industry certainly had plenty of "opportunities" in 1975. Considering the industry's generally lackluster 1975 profit record, and in view of the slowdown in inflation, there's some hope that 1976 might be a better year in spite of the increasing risks and uncertainties that plague the mining industry.

Jan 2, 1976

By Frank L. Gaddy

Falls of roof account for over 50% of the fatalities that occur in coal mines in the US. Thus, roof control is one of the more important phases of underground mining. In reality, the control of roof influences the system of mining and is a major determinant of the width and spacing of working places, operations at the mining face, ventilation control, and surface subsidence. Frequently, the control of roof is the largest single cost item. Roof control is a never-ending task, not only at the working face and throughout sections where men are working, but along haulways and air- ways that must be maintained for the life of the mine. This is because roof, even the best of roof, slowly deteriorates, so it must be frequently examined, with corrective support applied when needed. As coal is excavated, stresses are set up in the roof because the previous equilibrium is upset, resulting in pressures that cause fractures and slight movements that are frequently hard to detect. Unless the immediate roof, in the excavated area, is given support by artificial means, it might fall or there might be a succession of falls, varying from a thin scale to several feet, depending on the nature of the top. Exceptions to this are those rare mines, or sections of mines, with hard, strong, nonweathering roof that requires no support. GENERAL CLASSIFICATION OF ROOF There are two broad types of roof as far as support is concerned: the immediate roof above the coal and the main roof. Artificial support for mining purposes is only concerned with the immediate roof as nothing except large blocks of solid coal, or massive concrete, will support the main roof. The immediate roof is generally a few feet thick but can vary from inches to 6.1 m (20 ft) or more. There are examples of where there is no immediate roof as the massive main roof lies directly on the coal

Jan 1, 1981

By L. D. Jaffe, J. H. Hollomon

The effect of tempering temperature and time upon the properties of quenched steel is clearly a subject of great practical importance, as well as of considerable theoretical interest. It would be very desirable to be able to predict the properties of a quenched steel when given any selected tempering cycle, with a minimum of experimental work upon that heat or even type of steel. Two problems are involved: one consists of relating the structure obtained to the physical properties, and will not be discussed here; the other, with which this paper deals, involves the relations of time, temperature and composition with the structure obtained 011 tempering. Indentation hardness is perhaps the most convenient quantitative measure of the tempered structure, or of what might be called the "degree of tempering." Undoubtedly, it is not an exact measure, and in some cases (as when temper-brittleness occurs) pieces of the same quenched and tempered steel may have widely differing properties at the same hardness. However, hardness has the advantage of being simple to determine and is certainly the most widely used indication of the degree of tempering. Moreover, for fully quenched steels that are not temper-brittle and do not contain retained austenite when quenched, it appears that, in general, if the hardness of the steel is the same, the tensile and impact properties will also be identical, whether a high or a low tempering temperature is used. The tempering charts available in the metallurgical literature usually give the hardness as a function of tempering temperature for only one tempering time. However, in practice, tempering times frequently vary, and a method of converting tempering curves for one time to tempering curves for some other time would be very valuable. It is also advantageous, in determining the tempering treatment necessary for a given part, not to have to temper samples at several temperatures for the time used for the commercial tempering operation. A more satisfactory procedure would be to employ times of the order of 10 to 30 min., rather than 5 or 10 hr., and if possible to use only one temperature. Furthermore, it is frequently desirable, for reasons such as temper-brittleness,* to obtain a given hardness with short times at relatively high temperatures, and it would be convenient to be able to compute without tests the time required to produce this hardness. Remarkably few quantitative studies of the hardness of quenched steel tempered over wide ranges of temperature and time

Jan 1, 1945

By E. D. Fields, R. W. Sayers, M. C. Tippett

The Duval Corp. porphyry copper deposits at Copper Canyon and Copper Basin, though widely separated, form an econornic unit requiring integrated exploitation. Contrasts in mineralization, host rocks, and mode of occurrence present unique mining and milling problems. Mixed oxide-sulfide ore is treated in extensive dump leaching facilities in both areas. Complex Cu-Au-Ag ore is treated in a 4000-tpd mill at Copper Canyon. In both areas, hypogene metallization occurs within large aureoles of metamoiphism and hydrothennal alteration related to quartz monzonite intrusions of mid-Tertiary age. Supergene processes fitrther altered the rocks and enriched the hypogene protore. At Copper Canyon, hypogene copper and iron sulfides with gold and silver occur in fractures, as partial replacement of favorable beds, and as disseminations in Paleozoic sedimentary rocks. The lower part of the Pennsylvanian Battle formation was a particularly favorable host. Metallization occurs to a lesser extent in quartz monzonite. Metal zoning is well-developed. The deposits at Copper Basin consist principally of supergene copper minerals in arenites of the Cambrian Harmony formation. Oxidation of hypogene copper and iron sulfides in tactite zones has formed at least two commercial deposits; intersections of fractures with favorable beds exerted important ore controls. Recently, the Copper Canyon and Copper Basin properties of Duval Corp. have been added to the list of porphyry copper mines in Nevada, marking the first new copper open pit in this state in 15 years. The properties are situated in the Battle Mountain

Jan 1, 1970

By P. C. Upadhyay, J. G. Singh

Reissner's thick plate bending theory has been recast for rocks which exhibit the property of double elasticity: different Young's modulus and Poisson's ratio in compression and tension. The governing differential equation and other relevent expressions have been presented in a form compatible to the applied mechanics results so that they can readily be used. Effect of the ratio of Young's modulii in compression and tension, (Ec/Et), on the maximum plate deflection and the maximum bending moments has been evaluated over a wide range. It has been found that the inclusion of bi-modulus property through a parameter (ß = Ec/Et), changes the sheer deformation of the plate to such an extent that the bi-modular effect of rock cannot be overlooked in the thick plate analysis, especially when ß is expected to be greater than 2.

Jan 1, 1982

By A. F. Frederickson

Rapid advances in any branch of science often follow the development of new instruments or techniques which permit the scientist a closer look at the material in which he is interested. With the development of the polariz¬ing microscope, modern petrology was born. The resolving power of the microscope, however, was not great enough to enable the geologist to dis¬tinguish or identify the material now known to be minerals which constitute the bulk of the rocks known as "clays" and laterites. The discovery of X-rays and the development of powder X-ray diffrac¬tion techniques provided the extra resolving power necessary to get "a closer look" at the minerals in the clays and laterites. These techniques are largely responsible for the great strides made in the past two decades in the identification of the clay, sesquioxide and hydroxide minerals. To obtain an X-ray diffraction. pattern of a mineral or rock is relatively a simple procedure, but to interpret this pattern in terms of crystal structure or min¬eral identity is quite another matter. It has taken the combined talents of physicists, physical and colloid chemists, mineralogists, and geologists to unravel the identity of some of the minerals in these complex rocks and, as this symposium will indicate, many more problems remain to be solved. To assist in the identification of these minerals, we have the ever-useful microscope, which, is supplemented by the development, only in the last ten years, of differential thermal techniques and the powerful and costly "eye" that enables us to see the shapes and sizes of extremely small particles -the electron microscope. To this array of equipment must be added such gadgets as supercentrifuges, spectrographs, and the apparatus necessary for chemical analytical work. Obviously, not only is it difficult for any one man to master all of the techniques to the point where he can do competent re¬search, but also few institutions are able to provide the high capital outlay for purchase and maintenance of suitable equipment. Here we clearly see that if this equipment is to help us solve our many problems, a close co¬operation of specialists from various institutions and industry is essential. This, however, is less than half the problem. If the geologist is going to learn to intelligently find, and the industrialist to intelligently and eco¬nomically exploit the materials that constitute a large part of the mineral wealth upon which our way of life is based, we must get a better insight into

Jan 1, 1952

By Michael B. Bever, Barton Roessler

The effects of deformation by wire drawing at 78OK on initially ordered and initially disordered specimens of the alloy Cu3Au were investigated. The resistivity, stored energy, drawing force, and microhardness were measured as functions of strain; microstructural changes were observed. The results are interpreted in terms of the structural imperfections and the changes in atomic configuration resulting from deformation. A few experiments on the effects of room-temperature annealing after deformation at 78°K were made; they suggest vacancy-promoted ordering in disordered alloys. BARTON ROESSLER, Junior Member AIME, formerly Graduate Student and Alcoa Fellow, Department of Metallurgy, Massachusetts Institute of Technology, Cambridge, Mass., is with Westinghouse Research Laboratories, Pittsburgh, Penn. MICHAEL B. BEVER, Member AIME, is Professor of Metallurgy, Massachusetts Institute of Technology. Based in part on o thesis by B. ROESSLER submitted in October, 1959 to the Massachusetts Institute of Technology in partial fulfillment of the requirements for the degree of Doctor of Science. Manuscript submitted April 6, 1961. IMD AN investigation of the effects of deformation at room temperature on the alloy Cu3 Au was reported in a recent paper,' which included a review of the literature on the deformation of order-disorder alloys. In general, plastic deformation of ordered alloys reduces the degree of long-range order and causes corresponding changes in their properties. Deformation of disordered alloys changes their properties in a manner characteristic of solid solution alloys; these changes can in part be attributed to the destruction of short-range order. The effects of deformation on solid solution alloys are of two kinds: 1) generation of structural imperfections, which occurs as a result of deformation in any metallic system including pure metals, and 2) changes of atomic configuration, which are characteristic of solid solutions and particularly of order -disorder systems. These two types of effect are not independent of each other and the state of a deformed solid solution alloy is determined in a complex manner by the way in which the structural imperfections cause changes in atomic configuration both during and after deformation.

Jan 1, 1962

By L. L. Wyman

SINCE the presentation, by the writer, of the initial paper on the embrittlement of copper,1 the subject has been investigated further along two separate lines. The first series of investigations involves the "double-deoxidized" copper, while the second series is devoted to single deoxidizers other than those used in the investigations reported upon last year. The object of these experiments is to develop a type of copper that will show the minimum of detrimental effects after having been exposed to alternate oxidation and reduction. The fabrication of this material necessitates the use of alternate oxidizing and reducing atmospheres, at temperatures ranging up to 900° C. Following this treatment it is essential that the soundness and strength of the copper be unimpaired, even in sections of only a few thousandths of an inch in thickness.

Jan 1, 1932

By R. L. Templin

The increasing use of aluminum and its alloys in commercial fields tias demanded a better understanding of their machining properties. This fact is exemplified by problems that have arisen in the automotive and airplane industries, but many in other fields might be cited. As pure alunlinum and its alloys in their various commercial conditions show appreciable differences in their machining properties, it is not surprising that quite divergent solutions have been offered for the machining problems encountered. However, if the fundamental requirements of the most suitable cutting tools for these metals are understood, these machining problems lend themselves more readily to satisfactory solutions. Since the machining of free cutting brass and mild steel is understood by most persons accustomed to working these metals, it may serve our purpose better to first make a general comparison of the tools more commonly used in machining these metals with the tools most suitable for machining aluminum, then proceed to a more specific discussion of the individual tools. Comparison oF Cutting Tools Cutting tools commonly used for machining free cutting brass usually have little, if any, top and side rake; they are ground on a medium to coarse abrasive wheel and used without any cutting compound or with a cutting compound that has a paraffin base. Those ordinarily used for steel have some top and side rake, are usually ground on a medium to fine abrasive wheel, and are often used with soluble-oil cutting compounds. The proper tools for aluminum and its alloys should have appreciably more side and top rake than the tools for cutting steel; should have very keen edges obtained by grinding with fine or very fine abrasive wheels supplemented in many cases by hand stoning with an oil-stone; and should be used with suitable cutting compounds whenever possible. In many cases, tools suitable for machining aluminum and its alloys are not appreciably different from tools commonly used for cutting hardwoods. The front clearance of a tool most suitable for machining aluminum and its alloys should be about 6°, the top rake from 30" to 50°, making the total angle of the cutting edge of the tool from 35' to 55". A side

Jan 1, 1955

By C. J. Haigh

Stockpiled and currently produced zinc plant residues containing zinc ferrite are to be treated at a rate of 350 tonne per day in a plant that is being constructed at the Risdon works of the Electrolytic Zinc Company of Australasia Limited (E.Z.). Start-up of the plant is scheduled for December, 1970. The residue is to be treated by a hydrometallurgical process that was developed by E.Z. in Australia, by Det Norske Zinkkompani in Norway, and by Compagnie Royale Asturienne des Mines (Asturiana de Zinc) in Spain. The process, as it is to be used at Risdon, is simple, consisting essentially of two stages : 1. A leaching stage at atmospheric pressure in which the zinc ferrite contained in zinc plant residue is dissolved in spent electrolyte, fortified with make up sulphuric acid, at a temperature in the range 70 to 95ºC. Undissolved solids containing lead and precious metals are separated for sale to a lead smelter. 2. An iron precipitation stage at atmospheric pressure in which ferric iron is precipitated from a slightly acidic solution at 90 to 95ºC as ammonium jarosite, a crystalline double sulphate which is relatively coarse, and is easily filtered and washed free of zinc-bearing solution. Calcine is used to neutralise the acid that is liberated during precipitation of the iron. Also included in the Risdon plant are a separate stage for oxidation of ferrous iron by injection of air, and a pre-neutralisation stage, using recycled oxidation stage pulp, to neutralise excess acidity from the leaching stage before the jarosite precipitation stage. The residue treatment plant consists of conventional equipment such as covered agitated vessels, thickeners and filters. Operation will be continuous and product solution will join the main zinc plant circuit for further purifications and electrolysis. Marketable zinc production will be increased by 70 tonne per operating day by the treatment of residue.

Jan 1, 1970

By Irwin Roman

THE literature of geophysics as applied to the discovery of mineral deposits has been very extensive during the past few years,1 but there seem to be few references to the use of the method of least squares for obtaining better interpretations of the observed data .2 There seems to be a general reluctance among geologists and engineers to acquire the technique of least squares, in spite of the fact that a thorough knowledge of the theory is not necessary for the use of the method.

Jan 1, 1932