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By E. A. Gulbransen, J. W. Hickman

THE physical and chemical structure of the oxide films formed on metals and alloys is of interest in our understanding of their protective properties. According to Pilling and Bedworth,1 if the specific volume of the oxide is equal to or greater than that of the metal, a compact or continuous structure results; if the volume of the oxide is less, a cellular or porous structure forms. With the cellular type of coating the surface layer of oxide offers no impedance to oxidation; at a given temperature the rate of oxidation is quite constant. On the other hand, the compact type of coating acts as an effective barrier to oxygen and the rate of oxidation will follow a parabolic law. The recent work of Gulbransen2 and of Leontis and Rhines3 on the oxidation of magnesium indicates that it is not necessary for the volume of the oxide to be greater than that of the metal in order that the oxidation may follow a parabolic rate law. One exception to the rule of Pilling and Bedworth' is noted by Scheil;4 namely, tungsten. At 500° and 700°C long-time oxidations indicate a linear rate law with time. However, Dunn's5 oxidation measurements from 700° to 1000°C indicate that a parabolic rate law is followed. The oxide is mainly yellow W03 with a thin layer of the blue oxide. Preliminary results on the oxidation of tungsten6 in the temperature range 400° to 500°C indicate that the oxidation does proceed according to a parabolic rate law. Irrespective of the actual rate law that tungsten may obey, it is of interest to compare the results obtained on the oxidation of tungsten in the thin film region with those found when the metal is scaling. A time-temperature study of the oxides formed on both molybdenum and tungsten may indicate whether there exist any peculiarities in the oxide structures of the thin film region compared with those of the scaling region of oxidation. In a recent paper the authors' presented an investigation of the structures of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper. The results of these studies are presented in graphical form as existence diagrams of the oxides on a time-temperature scale. The existence diagrams of the oxides occurring on some of the metals are simple and show few chemical transitions, but there are many cases in which the physical state of the oxide surface changes as a function of time and temperature, as evidenced by the appearance or disappearance of orientation effects and sharpness of patterns. In general an increase in temperature results in an increase in

Jan 1, 1947

Discussion of the paper of Woolsey McA. Johnson, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 79, July, 1913, pp. 1137 to 1145. F. L. GRAMMER, Leesburg, Va. (communication to the Secretary *):-Mr. Johnson's paper must interest by suggestion those connected with the " burning " of lime, the production of cement, and the smelting of iron. All iron men know how quickly the impalpable purple ore of wet origin reduces compared to finely ground red hematites of approximately identical composition obtained from Lake lump ores. Most housekeepers appreciate that the several forms of carbon-charcoal, coke, and anthracite, not to include graphite and diamond -have different temperatures of ignition. The temperature usually rises with the density and hardness. Some of the scientific bureaus of the government might appropriately conduct some tests along lines suggested by Mr. Johnson's article. We are unable to say whether the topic lies within the spheres of activity of the Bureau of Mines, the Bureau of Soils (Agricultural Department), the Geological Survey, or the Bureau of Standards. The calcining qualities of limestone is a topic too wide for individual effort and is of wide enough interest to merit government or State activity. It is of interest, as aforesaid, to burners of lime, cement manufacturers, and smelters. The chemical composition of a limestone does not tell all the story -if over 1-in. size lumps. The limestones of Annville and Myerstown, Pa., break at a tap; those on the Hudson above Poughkeepsie .act like "nigger heads." The manager of lime kilns near Lake Champlain told me his fuel consumption was high compared to that at other points. Yet the Hudson and Annville stones were both of greatest purity, being rivaled by only the marble at Rutland, Vt., or some stones near Martinsburg, W. Va. A local kiln operator says the conglomerate or pudding limestones of Loudoun county, Va., act very differently in the kiln from the more normal limestone deposits nearby. The tilted and twisted bedding in the anthracite region tells the story of hard coal origin. We might therefore expect that the limestones of greater geological age or depth or metamorphism

Jan 11, 1913

By Arthur Coffinberry

EVE have studied the gold-aluminum system by X-ray diffraction and by the microscope over the entire range of composition for temperatures between 300° and 500° C. Results obtained are shown in Fig. 1, com-bined with the work of Heycock and Neville1 at higher temperatures. The diagram differs in important details from that given by Hansen2 in his critical compilation of the literature of binary alloy systems. This work was, undertaken both because of the intrinsic value of a knowledge of the phase diagram of this system and because of the need of theoretical metallurgy for precise and accurate data, particularly X-ray diffraction data. Systematic studies of equilibrium diagrams, particularly by Hume-Rothery,3 have shown regularities that yield a certain insight into the nature of alloying forces. It has been shown, for example, that solid solubility depends on the concentration of free electrons in the alloy, on the relative radii of solvent and solute atones, on the forces of attraction between atoms, and on the relative stability of intermediate phases. The well-known Hume-Rothery rule states that the crystal structures and compositions of many intermediate phases depend on the electron-to-atom ratio. This has been confirmed and extended by wave mechanical calculations.4 A knowledge of the forces between atoms in alloys, even an imperfectly developed empirical one, should be a valuable guide in the preparation of technological alloys of desirable properties. Furthermore, such informa-tion is basic in such problems as rate of diffusion, age-hardening, phase transformations, and others. The most valuable data for this purpose are furnished by X-ray diffraction studies. Unfortunately, work has been

Jan 1, 1938

By T. Carl Shelton

The coal industry of the United States in 1967 had reasons to be both exuberant and concerned about its present and future role in the economy of the country. Continuing a momentum that began in the early 1960's, the industry has moved ahead in providing competitive customized products to strengthen its long-term domestic and foreign commitments, and has maintained with steady progress its position as a major supplier of energy. On the other hand, the industry must overcome air- water pollution and conservation-reclamation problems that have been identified by 1967 legislation. Throughout the year, the industry was characterized as "progressive," "healthy" and "dynamic." To have been termed a "growth industry" in 1967, is an accolade the coal industry can accept with pride. Culminating its efforts throughout the decade, the industry has emerged with a competitive image that is representative of its future strength.

Jan 2, 1968

By Parviz Montazer, Robert King, William Ubbes, Gideon Chitombo

This paper describes the results of a detailed study that was undertaken to define the spatial distribution of permeability within a five meter thick envelope around the CSM/ONWI room. Detailed fracture orientations and distribution were determined through mapping of the walls of the opening, logging of oriented core, and visual examination of borehole walls with a borescope and a T.V. camera. Over 3,500 measurements were made from which the three dimensional distribution of fractures was determined. Two principally different testing equipment designs and various methods of air injection tests were used in all boreholes to identify and characterize conductive fractures. Through analizing the distribution of permeability and fracture index around the room a zone of blast damage of approximately .5 m thickness was delineated. The effect of stress modification seems to extend farther into the host rock to approximately 3.5 m depth.

Jan 1, 1982

By James Bowron

CONSIDERING the importance of the steel trade and the strategic position occupied in it by the Birmingham District, it may be surprising to many to realize that even the first pig iron smelted with coke was made in Alabama on Feb. 28, 1876, although merchant pig iron had been produced in Rockwood, Tenn., in 1867, a plant which is still in active operation. The heavy deposit of Clinton ore extending from Pennsylvania into Alabama, varying greatly in accessibility on account of geological changes such as erosion or anticlinal upthrow, varies equally as much in thickness and in quality. The brown ores extensively scattered through the South also vary materially in quality, some being relatively low in phosphorus and high in manganese, and vice versa. The red ore varies materially in phosphorus, but the iron produced from these ores was always considered to be too high in phosphorus for treatment by acid Bessemer or open hearth and did not contain sufficient for the basic Bessemer process. Under these conditions there remained only the basic open hearth as a possibility, and for many years it appeared impossible to use it, because, with coke smelted iron, the silicon was too high to permit its use in basic lined furnaces.

Jan 1, 1924

By M. G. Arthur

This paper is a theoretical analysis of fingering of water and coning of water and gas in homogeneous sand. Investigation of this idealized case illustrates the relative magnitude of the factors involved in actual conditions. The body of the report presents equations, example calculations, and charts that facilitate solution of such problems. Derivation of the equations introduced in this paper and a discussion of previously published equations are included in the appendix. Introduction Production of water from oil wells as a result of the pressure gradients established by flow of fluids through oil-~roducing sands is a common occurrence, which influences the cost of oil production, the degree of depletion and the efficiency of expulsion of oil from naturally occurring reservoirs. Control of water production and encroachment are important both in primary and secondary phases of of exploitation in order to produce oil and gas at lowest cost and in order to achieve the greatest ultimate recovery of the oil in the reservoir. Although many actual oil reservoirs present a multitude of variables that influence fingering and coning of water and gas, an inspection of the relationship and magnitude of the forces involved in the case of a homogeneous sand may indicate satisfactory methods of controlling water production. Application of equations relating the variables may indicate the geometric type of drainage that exists in a particular reservoir or in the vicinity of a particular well. A homogeneous sand body is assumed within the portion of the reservoir influenced by the well. Two geometric types of drainage are considered theoretically. The first is water fingering into an oil sand that is relatively thin compared with the lateral extent of the sand. This sand may represent the entire oil-producing reservoir or it may represent one interval in an oil reservoir, which is separated from other producing intervals by competent lithologic barriers to flow of fluids. For the condition of complete penetration of a well in such a sand body, it may be assumed that no flow occurs across bedding planes. A mathematical relation is developed between the limit of approach of a water finger to the well without being drawn into the well and the corresponding operating pressure drawdown. The second condition considered is that of water or gas entry into an oil well as the result of coning through bedding planes. The theory and graphical solution developed by Muskat' for the limit of approach of a water or gas cone to a well, without its entry into the well, related to the corresponding maximum pressure drawdown, is reviewed and amplified, Charts are presented, which facilitate graphical solution of the problem. A method is presented for the extension of this type of graphical solution to the case where gas and water coning occurs simultaneously~

Jan 1, 1944

By M. G. Arthur

This paper is a theoretical analysis of fingering of water and coning of water and gas in homogeneous sand. Investigation of this idealized case illustrates the relative magnitude of the factors involved in actual conditions. The body of the report presents equations, example calculations, and charts that facilitate solution of such problems. Derivation of the equations introduced in this paper and a discussion of previously published equations are included in the appendix. Introduction Production of water from oil wells as a result of the pressure gradients established by flow of fluids through oil-~roducing sands is a common occurrence, which influences the cost of oil production, the degree of depletion and the efficiency of expulsion of oil from naturally occurring reservoirs. Control of water production and encroachment are important both in primary and secondary phases of of exploitation in order to produce oil and gas at lowest cost and in order to achieve the greatest ultimate recovery of the oil in the reservoir. Although many actual oil reservoirs present a multitude of variables that influence fingering and coning of water and gas, an inspection of the relationship and magnitude of the forces involved in the case of a homogeneous sand may indicate satisfactory methods of controlling water production. Application of equations relating the variables may indicate the geometric type of drainage that exists in a particular reservoir or in the vicinity of a particular well. A homogeneous sand body is assumed within the portion of the reservoir influenced by the well. Two geometric types of drainage are considered theoretically. The first is water fingering into an oil sand that is relatively thin compared with the lateral extent of the sand. This sand may represent the entire oil-producing reservoir or it may represent one interval in an oil reservoir, which is separated from other producing intervals by competent lithologic barriers to flow of fluids. For the condition of complete penetration of a well in such a sand body, it may be assumed that no flow occurs across bedding planes. A mathematical relation is developed between the limit of approach of a water finger to the well without being drawn into the well and the corresponding operating pressure drawdown. The second condition considered is that of water or gas entry into an oil well as the result of coning through bedding planes. The theory and graphical solution developed by Muskat' for the limit of approach of a water or gas cone to a well, without its entry into the well, related to the corresponding maximum pressure drawdown, is reviewed and amplified, Charts are presented, which facilitate graphical solution of the problem. A method is presented for the extension of this type of graphical solution to the case where gas and water coning occurs simultaneously~

Jan 1, 1944

By C. R. St. John, R. W. Lindsay, Charles R. Austin

Many of the factors influencing the creep behavior of ferrous alloys have been investigated and reported upon in the literature, including such variables as grain size, steelmaking practice, nature and stability of the microstructure, and the effect of alloying elements in steels. However, with respect to the latter, the microstructures involved are usually heterogeneous and as a result the effect of the addition is related to its effects on the various phases present in the microstructure. In the instances where this structure consists of ferrite and carbide, the behavior of the alloy addition will be related to its action in strengthening ferrite and in opposing temperature softening of ferrite as well as coalescence of carbide. The present paper is the third in a series comprising a comprehensive review of investigations on the properties of iron binary alloys.l,2 Its purpose is to describe the results of isolating one microstructural phase, namely ferrite, and studying its creep characteristics in both the unalloyed and alloyed conditions. This should aid in establishing to a large degree the importance of ferrite in the creep behavior of steels consisting of the previously mentioned ferrite-carbide aggregate. In view of the fact that the present investigation deals only with the effects of silicon, manganese, chromium, molybdenum, nickel, and cobalt, and to a certain extent with the effects of carbon, the review of previous literature will be confined to these elements. Practically no references were encountered dealing with the influence of these elements on the creep characteristics of the isolated phase. However, various contributions have dealt with the creep behavior of low-carbon steels alloyed with the elements under consideration. A particularly concise review in this respect is given by Bullens (Battelle)= and much of this material has been drawn upon. The definite improvement in creep resistance and high-temperature strength conferred by molybdenum is well known. Published suggestions by the A.S.M.E.4 permit of an increase of some 2000 to 5000 lb. per sq. in. in permissible design loads over a temperature range from 650" to IOOO °F. as a consequence of additions of 0.40 to 0.60 per cent of this element in carbon steels of the order of 0.25 to 0.35 per cent carbon content. Babcock and Wilcox Tube CO.5 has published data showing the pronounced increase in stress necessary to cause one per cent creep per 10,000 hr. when additions of 0.5 or I per cent molybdenum are made to a plain carbon steel. These data apply to temperatures over a range from 800° to1000°F. 4

Jan 1, 1945

By A. F. Brock

The cut-and-fill mining methods in use in the mines of The International Nickel Company of Canada Limited, at Falconbridge Nickel Mines Limited, in the Sudbury District, and at McIntyre Porcupine Mines Limited in the Porcupine District, are typical of the general cut-and-fill practice in both the base-metal mines and the gold mines in the Province of Ontario. The following pages describe the methods in use. HORIZONTAL CUT-AND-FILL STOPING Horizontal cut-and-fill stoping, as practiced in the mines of The International Nickel Company of Canada Limited, falls into two main classifications: (I) transverse cut-and-fill stoping, where ground conditions or wide ore bodies make it necessary to establish narrow stopes and pillars across the width of the ore body; (2) longitudinal cut-and-fill stoping where ore body widths and ground conditions allow safe mining of the full width of the ore body. Transverse Cut-and-fill StopiNg General Stoping Layouts Stope and Pillar Widths.—For transverse stoping, experience has indicated that narrow stopes and pillars, 27 ft. 6 in and 22 ft., respectively, are most satisfactory. These width are multiples of 5 ft. 6 in., which is the center to center dimension of a standard square set. Thus any stope, or block of stopes, can be readily converted from cut-and-fill to square set-and-fill if ground conditions should warrant such a change. Formerly, pillars were established 16 ft. 6 in. wide, the equivalent of the width of three square sets, with the intention of extracting the pillars by mining an overhand slice one set wide and an underhand slice two sets wide. However, subsequent experience proved that a two-set overhand slice is so much more efficiently mined than a one-set slice, and 22-ft. pillars have been made standard. Chutes.—The stope chutes are established on the longitudinal center line of the stopes and are spaced at 22-ft. centers from footwall to hanging wall. The footwall chute is usually from 5 to 10 it. from the footwall of the stope. It is offset where necessary at an angle of 52° and vertical chutes are carried from the offset at 22-ft. centers. In sections of the ore body where a flat hanging wall would cut off hanging-wall chutes within a few cuts of the sill, it has proved to be more economical to use temporary chutes or slushers, or both, for these first few cuts, rather than to el permanent chutes at the hanging wall.

Jan 1, 1946

By C. H. Li, R. J. Stokes

This paper compares the fracture behavior of tungsten rods in three conditions: recrystallized. recovered, and wrought. Notched specimens suhjected to a 50 in.-lb impact load showed ductile-brittle transitions at 700, 4.90°, and 440°C, respectinely. The recrystallized material had an equiaxed pain structure and jracbred by simple cleavage from a grain boundary source at all temperatures up to 700°C. The wrought and recovered material had an elongated fibrous structure and at low temperatures fractured by cleavage originating from the notch. As the transition temperature was approached cleavage was preceeded by more and more intergvanular splitting which deflected the crack front into planes parallel to the tensile axis. The enhanced toughness of wrought and recovered tungsten was attributed both to its inability to initiate cleavage because no pain boundaries were suitably oriented perpendicular to the tensile stress and to its inability to maintain cleavage because of intergranular splitting ahead of the crack. It has been appreciated for a long time in a qualitative manner that the room-temperature brittleness of fully recrystallized tungsten may be alleviated by working the material at relatively low temperatures.' More recently this difference in mechanical behavior between wrought and recrystallized tungsten has been examined quantitatively by measurement of the tensile properties as a function of temperature. In these experiments brittleness has been expressed in terms of ductility or reduction in cross-sectional area upon tensile fracture or in terms of the bend radius before fracture under bending.' This work has shown the existence of a fairly sharp transition from brittle to ductile behavior with an increase in temperature. The ductile-brittle transition temperature for recrystallized material is approximately 200°C higher than for wrought material. An increase in strain rate, small additions of impurity,' or an increase in grain size4 shift the respective transition temperatures to higher values, but the difference between them remains approximately the same at 200°C. A number of explanations for this embrittlement by recrystallization have been given. It has been blamed either on the concentration of impurity at the grain boundaries, the increase in grain size, or the change in texture which occurs upon recrystallization. The present paper examines the effect of different heat treatments on the notch-impact behavior of commercial powder-metallurgy tungsten rods. The change in the ductile-brittle transition temperature for this method of loading and the fracture mode has been related to the different mi-crostructures produced by heat treatment. EXPERIMENTAL PROCEDURE Commercial swaged powder-metallurgy tungsten rods 1-3/8 in. in length and 1/8 in. in diameter were machined to introduce a sharp V notch 0.030 in. deep. To change the microstructure from that of the as-received wrought material some of the specimens were subjected to an anneal in nitrogen either at 1300° or 1400°C for 8 hr or at 1600° or 2000°C for 1/2 hr. The notched rods were then placed in a miniature Charpy-type impact machine and struck at their midpoint (opposite the notch) with a hammer designed to deliver 50 in.-lbs of energy. The strain rate at the base of the notch was estimated to be approximately 100 sec-1 at the instant of impact. The specimens were heated in situ to the desired impact temperature. The microstructures produced by the various anneals were studied by both X-ray diffraction and metallographic techniques. Fig. 1 reproduces the microstructures observed metallographically following a 10-sec electroetch in a 10 pct KOH solution. Fig. l(a) shows the elongated fibrous grain structure of the as-received material. Following the anneal at 1300" or 1400°C the grain structure was still elongated as shown in Fig. l(b) but the etch pits delineated dense polygonized dislocation arrays within many of the grains. Occasionally a relatively dislocation-free recrystallized grain was found growing into the matrix. The anneals at 1600° and 2000°C resulted in complete recrystallization and some grain growth. The grains produced at 1600°C were still slightly elongated as shown in Fig. l(c) whereas the anneal at 2000°C produced equiaxed grains. The changes in grain size produced the expected changes in the X-ray back-reflection patterns; there was no indication either in the as-received material or the annealed material of any preferred orientation. RESULTS a) Impact Behavior. Fig. 2 reproduces the ductile-brittle transition curves measured in the manner described in the previous section. It can be seen that under these testing conditions the as-received

Jan 1, 1964

By J. L. SCHUELER

THE writer has reread Mr. Ingalls' interesting article in the July, 1923, issue of MINING AND METAL- LURGY on "The Use of Spelter in Galvanizing." It seems that most writers, in commenting upon coatings of spelter on sheets and wire, dwell upon the thin coatings which these materials carry, and rightly so. However, they seem to forget that until very recently, in the case of wire, the manufacturer did not know how to apply a heavy coating of spelter to the wire, especially if the wire was to be woven into fence or fabricated in some other manner, because heavy coatings of spelter are exceedingly brittle. This is even true in the case of high-grade spelter, but to a lesser degree than with Prime Western. Because of this brittleness, it has been necessary for wire manufacturers to smooth the coating by passing the wire through tightly compressed wiping means of some kind, usually asbestos. This removes all of the excess spelter and allows only a thin coating to remain. The latter, as a rule, is malleable and the wire can be fabricated without material injury to the coating.

Jan 1, 1924

By G. B. Gibbs

Various semiempirical equations which relate defect-formation energies and entropies with elastic and thermal properties of a metal crystal are shown to be related by a simple model for lattice energy. An illustrative comparison of theory with experiment is made using self-diffilsion data for fee metals. SEVERAL workers have related the free energy of defect formation with elastic and thermal properties of a crystal lattice, particularly elastic bulk modulus and Debye temperature. The present note shows how the various approaches are related by a simple model for lattice energy. A comparison of theory with experiment is given using the self-diffusion parameters of fee metals. 1) A MODEL OF THE CRYSTAL LATTICE The internal energy per atom in a metallic lattice may be written U=Ui-Ue [1] where Ui and Ue refer to ion-ion interaction and valence electron energies, respectively. The volume per atom V has an equilibrium value 52 for which

Jan 1, 1968

By Michael B. Bever, Carl F. Floe

The solubility of hydrogen in molten copper-tin alloys is of both practical and theoretical interest. From a practical standpoint, data on the equilibrium solubility as a function of temperature, pressure and alloy composition are valuable for a better understanding of porosity problems in bronze castings. From the theoretical point of view the determination of the hydrogen-copper-tin equilibrium is of interest since it extends the laws governing the solution of gases in metals. This paper presents the results of an investigation of the solubility of hydrogen in representative compositions of the copper-tin system at temperatures ranging from above the liquidus to I300°C. and at pressures from less than 50 mm. of mercury to about atmospheric. Review of Previous Work The solubility of hydrogen in copper was determined by Sieverts and Krumbhaarl in 1910 and by Roentgen and Moeller2 in 1934. Their values are in fair agreement. In 1926 Iwasé3 reported results that were very much higher. The published data on the solubility of hydrogen in tin do not agree. Smithells4 states that no reliable data are available According to Sieverts and Krumbhaar,5 hydrogen is insoluble in tin. Bircumshaw,6 on the other hand, found a definite solubility at 800°C. The latter's experimental procedure did not provide for stirring of the metal and in his opinion he failed to reach equilibrium. Iwasé3 again reported large solubility values. For copper alloys, Sieverts and Krumbhaar5 distinguished between alloying elements that do not markedly affect the solubility of hydrogen, elements that increase the solubility, and elements that reduce it. They named gold, tin, and aluminum as examples of this last group and reported hydrogen solubility data at 1225°C. for the copper-rich side of these alloy systems at atmospheric pressure. Without giving experimental results, they stated that the amount of hydrogen dissolved by liquid copper alloys is proportional to the square root of the pressure as in pure metals. These authors suggested that in a limited way the effect of an alloying element on the solubility of a gas is related to the constitution diagram for the alloy system. Sieverts7 also called attention to the fact that the curve of hydrogen solubility versus composition of copper-tin alloys shows a sharp change of direction at the composition of Cu3Sn and suggested that this compound persists at least to some extent in the molten state. Iwasé3 reported large hydrogen solubility values for several compositions of copper-tin alloys, which appear to be in error.

Jan 1, 1944

By Carl F. Floe, Michael B. Bever

The solubility of hydrogen in molten copper-tin alloys is of both practical and theoretical interest. From a practical standpoint, data on the equilibrium solubility as a function of temperature, pressure and alloy composition are valuable for a better understanding of porosity problems in bronze castings. From the theoretical point of view the determination of the hydrogen-copper-tin equilibrium is of interest since it extends the laws governing the solution of gases in metals. This paper presents the results of an investigation of the solubility of hydrogen in representative compositions of the copper-tin system at temperatures ranging from above the liquidus to I300°C. and at pressures from less than 50 mm. of mercury to about atmospheric. Review of Previous Work The solubility of hydrogen in copper was determined by Sieverts and Krumbhaarl in 1910 and by Roentgen and Moeller2 in 1934. Their values are in fair agreement. In 1926 Iwasé3 reported results that were very much higher. The published data on the solubility of hydrogen in tin do not agree. Smithells4 states that no reliable data are available According to Sieverts and Krumbhaar,5 hydrogen is insoluble in tin. Bircumshaw,6 on the other hand, found a definite solubility at 800°C. The latter's experimental procedure did not provide for stirring of the metal and in his opinion he failed to reach equilibrium. Iwasé3 again reported large solubility values. For copper alloys, Sieverts and Krumbhaar5 distinguished between alloying elements that do not markedly affect the solubility of hydrogen, elements that increase the solubility, and elements that reduce it. They named gold, tin, and aluminum as examples of this last group and reported hydrogen solubility data at 1225°C. for the copper-rich side of these alloy systems at atmospheric pressure. Without giving experimental results, they stated that the amount of hydrogen dissolved by liquid copper alloys is proportional to the square root of the pressure as in pure metals. These authors suggested that in a limited way the effect of an alloying element on the solubility of a gas is related to the constitution diagram for the alloy system. Sieverts7 also called attention to the fact that the curve of hydrogen solubility versus composition of copper-tin alloys shows a sharp change of direction at the composition of Cu3Sn and suggested that this compound persists at least to some extent in the molten state. Iwasé3 reported large hydrogen solubility values for several compositions of copper-tin alloys, which appear to be in error.

Jan 1, 1944

By H. D. Hagen, C. E. Nelson

14.1-1. Coal Mining. CORPORATE STRUCTURE. Most coal companies that operate surface mines had their beginnings as basically one-man organizations, with all decisions and controls in the hands of the founder. At the early stage of the company development, it is usually quite possible for one man to handle all management functions as the mining operations generally are quite localized and the founder can have a first-hand knowledge of all facets of the operation. However, with continued growth, the entrepreneur finds that he must limit himself more and more to the top level of management and delegate the day-to-day operation to others. An organization must be developed that provides not only for current operations but also for continued growth of the company through acquisition of coal reserves in market areas that the company desires to serve. In general, a successful coal company engaged in surface mining must develop an organization consisting of the following departments or divisions: operations, sales, engineering, exploration, land, purchasing, financial, and legal. Of course, all of these departments are not required in the beginning. When the company is small, there is much overlapping of functions. For instance, the operating department will handle purchases and the engineering department will also handle exploration and land functions. A growing surface-mining company has generally evolved through the various stages of development into an organization that is typical of large mining companies. An examination of a typical company and its various departments and their functions should give an insight into the organizational trends of surface mining companies. Having begun as a typical one-man organization, a company of today can be highly centralized, with firm control of all phases of the company's operations in the executive offices. This is achieved by having all department heads (Fig. 14.1-I), as well as the senior management, based in central offices.

Jan 1, 1968

By C. R. Kuzell

GEOGRAPHICAILY the industry of reducing and refining of copper continued to migrate from the .United States during 1931. While this country is losing the predominant position of its copper industry, our engineers still enjoy their pre-eminent position as leaders in the design and operation of the new plants being brought into production in the four quarters of the globe. Progress in the art, as indicated by the construction of the recently completed works, has not been revolutionary. Standard methods have been followed, augmented by novel features in flow-sheets demanded by the results of progress in the art of ore-dressing, and by reason of problems incidental to the peculiarities of the new ores being treated. Design and construction progress has likewise been orderly and without radical departure from less recent practice; new features in primary and secondary equipment being logical developments to provide for special conditions to keep abreast of improve¬ments in accessory apparatus. The new plants are being rapidly brought in without hazardous novelties and for the purpose of yielding the principal ingredient, copper, in as large a volume as it will he possible to market; the old United States procedure. In the meantime the domestic plants are shut down or operating at a very low capacity, threatened with untimely demise unless the metallurgist can extract and develop other valuable products from the ores. International agreements .and tariff protection may be a temporary reviving stimulant, but for many mines the days of profit will be numbered unless the ores can be made to yield as values the ingredients now being discarded. Invisible progress in this direction has been made during the past year, and it is to he hoped that time will prove that the outstanding progress of 1931 was in the development of processes for the ultimate recovery of by-products from copper ores, perhaps even relegating the value of the copper yield to secondary importance.

Jan 1, 1932

By R. E. Somers

Discussion of the paper of R. E. SOMERS, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 101, May, 1915, pp. 957 to 996. A. C. LAWSON, Berkeley, Cal.-One point to which Mr. Graton (in summarizing the paper for us) called attention is that the author had not explained why some copper was fixed in the zone of oxidation. I recollect very well puzzling over that question at Ely, Nev., some years ago. Mr. Sales, in his paper on Butte,1 suggests the explanation. It is clue according to him to the paucity of pyrite in the primary ore. Where there is abundant pyrite sufficient sulphuric acid is formed by oxidation to take all the copper into solution and carry it to lower levels; but where the pyrite is scant so that insufficient sulphuric acid is formed, some of the copper is carbonated and so fixed in the gossan. The hypothesis, or some modification of it, as for example the combination of the sulphuric acid with lime, would appear to explain satisfactorily the fixation of the copper in the gossan as carbonate. I have, however, had no occasion in recent years to study the phenomenon. L. C. GRATON, Cambridge, Mass.-As I remember, the rocks in which the chrysocolla occurs in the Burro Mountains are both silicified and kaolinized. It seems probable that in surroundings deficient in carbon dioxide, complete oxidation of chalcocite may yield chrysocolla up to a maximum of half the copper in the chalcocite; while in rocks, like garnet contact zones and certain easily decomposable porphyries, surface decomposition appears often to yield silica in the necessary form to convert the copper of primary sulphides into chrysocolla immediately and directly upon oxidation.

Jan 12, 1915

By E. C. W. Perryman

On electropolishing, high-purity Cu-Sn and Cu-Sn-P alloys with more than 5 to 9 pct Sn were found to contain many grain boundaries with a ridge-and-furrow profile. The effect was not eliminated by solution treatment and was present at the new boundaries in recrystallized material. It could be produced by diffusing tin into the 3 pct Sn alloy and it is concluded that the effect is due to enrichment of certain boundaries in tin, or possibly in an impurity present in the tin, in solid solution. IN the hot working of tin bronzes, especially those with moderately high tin contents, considerable difficulty is frequently encountered from intercrystal-line weakness, which results in cracking at the edges in sheet on strip rolling and in the unsupported regions of the rod in rod rolling.' These difficulties are not at all pronounced with up to 3 pct Sn, but at 5 pct Sn impose serious limitations and at higher tin contents, especially if the phosphorus content is also high, they may become very severe. In some work carried out at the laboratories of The British Non-Ferrous Metals Research Association it was found that a notable lack of ductility in tension at elevated temperatures, associated with intercrystal-line failure, was characteristic of tin bronzes even of relatively high purity. That the intercrystalline fracture is not due to a brittle or molten impurity phase at the grain boundaries was shown by the fact that the temperature at which intercrystalline fracture first occurred decreased with decrease of rate of straining. Tensile tests on some commercial tin bronzes, reported by Goetzel,² show a similar fall in ductility with increasing temperature. As no visual evidence had been obtained showing that the grain boundaries of the tin bronzes were different from those in copper, a more detailed microscopical examination was carried out, and the results of this are given in the present report. Several workers"' have observed that electrolytic polishing is a powerful tool for detecting small amounts of a second phase and in particular for detecting high solute concentrations, "equilibrium segregation," at grain boundaries. Since it had been found that the suggested solutions for electropolishing bronze and the standard solutions for brass and copper did not give satisfactory results it was first necessary to find a suitable electropolishing solution.' Experimental Procedure Materials Used: The cast and wrought materials used for this work were the same as those used for the mechanical tests referred to above. They comprised 3, 6, and 9 pct Sn alloys without phosphorus and the same three basic alloys with 0.03 and 0.4 pct P. A 5 pct Sn alloy without phosphorus, of similar purity, was also examined. The basis materials were Chempur tin, high purity 15 pct phosphor-copper and cathode copper, and spectrographic analyses are given in Table I. Treatment: The cathode copper was first melted under charcoal, degassed by plunging marble chips beneath the surface, and cast through a coal gas flame into sand molds to produce a number of small ingots which after machining were of a suitable size for subsequent vacuum melting. Chill cast bars of the alloys, approximately 1¼ in. in diameter, were then made by melting and casting in vacuo, the tern-

Jan 1, 1954

By W. R. Ingalls

Jan 1, 1922