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By Louis A. Carapella, Ralph Hultgren

When F. Heuslerl found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.% All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys4 the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intellgently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data. have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. Previous Work In the original work of F. Heuslerl and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for CusMnAl of I = 443 was early measured. Ross and Gray5 found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler's original alloy. F. Heusler6 hen reinvesti-gated the system, confirmed their results,

Jan 1, 1942

By M. E. Wadswort, A. S. Peck

Infrared data disclose that phenacite reacts with oleic acid to form a chemisorbed oleate monolayer on the mineral surface. The absorption band characteristic of the antisymmetrical C = 0 oleate structure appears at a spectral wavelength of 1623 cm-'. Chemisorption also results in the displacement of OH- and silicate from the mineral surface. Infrared absorbance at 1623 cm-1 is correlated with float-ability at different pH for -60-mesh phenacite particles. Phenacite, Be2SiO4, is an ore mineral often associated with quartz, microcline, and chrysoberyl in pegmatites and mica schist. Experimental phenacite beneficiating processes have been confined principally to the flotation of low grade ores occur-ing in several mountain ranges of Utah and Nevada. The U.S. Bureau of Mines ' has recently reported on the separation of phenacite from ore deposits of Mount Wheeler, Nev. Infrared techniques were previously applied by the authors to characterize the role of sodium oleate and oleic acid in the flotation of several non-sulfide minerals.23 A parallel study was projected to the flotation of the orthosilicate mineral phenacite with oleic acid. Infrared spectra provided a 'molecular fingerprint' of the mineral surface and permitted identification of the reaction mechanisms. Infrared data were complemented with flotation and chemical tests. EXPERIMENTAL PROCEDURES The experimental procedures used in this investigation, for which data are presented in graphical or spectral form, are described in chronological test order. Phenacite crystals from Mt. Antero, Colo., were obtained from Ward's Co., Monterey, Calif. The crystals were fragmented in a porcelain mortar to -60 mesh and then pretreated with 0.5 molar HC1 for 15 min to remove iron. Then, the mineral particles were washed free of acid with distilled water and dried. Part of the dried material was ground to a fine powder with a Fisher Grinder using an agate mortar and pestle. Next, the powder was placed in a graduated cylinder and mixed with 500 ml of distilled water. The mineral in suspension was decanted from the settled fraction after 5 min, and the colloidal suspension was used for adsorption tests in which a high specific mineral surface area was required for adsorption and infrared analysis. Conditioning was performed in 50 ml glass centrifuge tubes for both infrared and flotation test determinations. Twenty ml of colloidal suspension was used for the infrared adsorption tests. One and a half g of deslimed -60-mesh HCl pretreated phenacite was added to 20 ml of distilled water for flotation conditioning tests. Six mg of oleic acid was used for each infrared adsorption test, and 0.2 mg of oleic acid was used for the flotation conditioning tests. HCl and NaOH were used for pH modification. The pulps were stirred at a speed of about 1500 rpm for 3 min. Then, the solids were separated out and either dried at 50°C or immediately transferred to a float cell. The pH of the residual liquid was determined with a Beckman Zeromatic pH meter. The flotation procedure is described as follows: 1) A 325-1111 glass micro-float cell was filled with distilled water. 2) Conditioned mineral was placed in the cell and the pulp was aerated through the glass fritted bottom at 7 psi pressure. 3) Floated mineral was skimmed from the cell with a glass slide until flotation ceased. (The end point was reached in all tests in less than 2 min.) 4) The flotation products were dried, weighed, and the recovery was calculated. Samples for infrared analysis were made into mulls using either oleic acid or series 13-21 Halocarbon oil obtained from Halocarbon Products Corp., Hacken-sack, N.J. The mulls were placed between two sodium chloride windows. A characteristic phenacite infrared band at 1868 cm-' was used as an internal standard for quantitative determinations in which absorbance at this position was quantified by the baseline-tangent method4 and related to absorbance at 1623 cm-'. The ratio obtained by dividing absorbance at 1623 cm-' by absorbance at 1868 cm-' was defined as an absorbance quotient for use in graphical presentation.

Jan 1, 1968

By H. Dykstra

Calculated wellbore pressures were obtained for parameters of radilcs ratio and permeability. In all cases bur two, after-production was allowed to occur for one day. The calculated pressure build-up data were compared with actual pressure build-up data from a condensate well. The paper discusses the comparison, gives reasons for, inability to match calculated (2nd actual data, and presents conc1usions derived from the comparison. INTRODUCTION Considerable information has been published on the decline in wellbore pressure for oil and gas fields resulting from production of fluids. Considerable information also has been published on pressure build-up for oil fields, but relatively little has been published for gas and condensate fields. Perrine' summarized the equations derived for pressure build-up in oil wells and showed how the different methods could be applied. On the other hand, very little theoretical information has been published on pressure build-up in gas or gas-condensate wells.2-4 Tracy,' by pointing out the similarity between the equation describing oil wellbore pressure decline and the equation describing gas wellbore pressure decline, showed how methods of pressure build-up analysis could be applied to a gas well. In analyzing pressure build-up data for gas or gas-condensate wells, it would be very desirable to compare actual pressure build-up data with calculated pressure build-up data. Such a comparison would lead to a better feeling for the quantitative picture of gas-well build-up curves and would help to establish a degree of confidence in a given build-up curve. This paper discusses the comparison and presents conclusions made from it. Calculated wellbore pressures are given for parameters of radius ratio and permeability. In all cases but two, after-production was allowed to occur for one day. The work was done in an attempt to evaluate the reserves of a gas-condensate field. As will be discussed later, it was not possible to make an evaluation. METHOD OF CALCULATION The method used for solving the depletion and pressure build-up behavior for a gas-condensate well was that developed by West, Garvin and Sheldon.5 or the IBM 704 computer program used, it was assumed that liquid condensing out of solution would have only a minor effect on the flow behavior. Therefore, the field was treated as having single-phase flow, with the gas saturation S, remaining constant at unity minus the connate-water saturation Sw. As will be discussed later, this may not have been a good assumption. It also was assumed that oil production could be considered as equivalent gas production by using a conversion factor based on an analysis of the liquid produced. An outer boundary condition of no-flow was assumed. BASIC DATA The data required for the study were reservoir properties, fluid properties and production data. Reservoir properties included the following: thickness h, 179 ft; porosity, 0.194; connate-water saturation, 0.43; gas saturation, 0.57; permeabilities k, 1.0, 0.5, 0.25 and 0.15 md; radius ratios re/rw, 800, 1,000 and 2,000; wellbore radius rw, 5 in.; initial reservoir pressure P, 6,529 psia; and reservoir temperature, 272°F. The selection of permeabilities was based on core-analysis data showing an average air permeability of about 2 md. With a relatively high connate-water saturation, the average effective gas permeability would be about one-half, or less, of the air permeability. The selection of radius ratios was based partly on the observed rapid decline in wellbore pressure during production and partly on the fact that the well was believed to be located in a relatively small fault block. Reservoir fluid properties were obtained from a reservoir fluid study on a recombined sample of gas and condensate. Gas formation-volume factors were calculated from pressure-volume measurements made at reservoir temperature. Gas viscosities were calculated by the method of Carr, et al,G from an analysis of the re-combined sample. These data are shown as a function of pressure in Table 1. The production schedule from the gas-condensate

By Max Roesler

W. L. CUMINGS,* Bethlehem, Pa. (communication to the Secretary+). -In this discussion of Mr. Roesler's paper, I shall follow Kemp in using the term "granite" to refer to the acid rock called syenite by Kimball. Diorite, as I understand it, is the dark basic rock invariably closely associated with the orebodies. The types of rock of intermediate composition, mainly intrusives, are not under discussion. It is difficult for me to conceive that this granite is the ore-bearing agent, for the following reasons: 1. No isolated orebodies in the granite are known. It would seem that if this rock is the mineralizer, some small bodies, or at least patches and small masses of ore so situated would exist. 2. In 1909 the writer conducted explorations on the Pequena and Grande claims about 1 mile north of West Mine No. 5. This work was done after a very careful magnetic survey had shown a large and uniform area of attraction. As exploration progressed, it became evident that in this case the magnetic attraction was due to disseminated magnetite. Much ore of 40 per cent. Fe was found, but very little commercial ore was shown up. This ore was entirely in the diorite and no granite outcrops are near. The occurrence could easily have been described as "ore formation but very little ore." I cannot conceive how a remote granite intrusion could impregnate a diorite mountain with 40 per cent. of Fe, and prefer to believe that this 40 per cent. of iron was in its real home, rather than in a sort of dioritic "boarding house" after having been evicted by granitic parents. 3. The Ocaña mine, which has produced nearly 500,000 tons, shows no evidence that the granite is the mineralizer. This is admitted by Mr. Roesler on p. 1827. 4. I believe it will not be disputed that all the iron-ore deposits extending along the south coast for 60 or 70 miles are of a similar origin. Evidence available at other points might properly be referred to in discussing the article under review. At the La Plata mines, about 60 miles west of Santiago, the writer has also made explorations. No granite is in evidence. At one point in the bed of a creek is a small body of magnetite about 10 ft. long, entirely surrounded by a hard fresh diorite. To me

Jan 3, 1917

Executive HOWARD N EAVENSON, Chairman FREDERICK M. BECKET EDGAR RICKARD ERLE V. DAVELER WILLIAM WRAITH Finance HENRY KRUMB Chairman PAUL D. MERICA J V W REYNDERS H G MOULTON, Consultant Admissions JOHN M LOVEJOY, Chairman GEORGE D BARRON - DONALD M LIDDELL ELI T CONNER - WILLIAM W LYNCH

Jan 1, 1935

By F. M. Drake

IN this paper I propose to describe a plant which I lately erected for the Mount Stewart Lead and Silver Mining Company of Leadville, New South Wales, Australia. I am indebted to Mr. W. F. Burrow, of the Roads and Bridges Department of New South Wales, for the drawings which I present herewith, he having reduced and assembled them from my working drawings. The works are situated on a sloping hillside, but sufficient fall mas not available to have the furnace as high as desired, and at the same time have a good slag-tip and sufficient depth on the ore-floor to store a supply of ore and flux. The ore is delivered on the ore-floor (which is of the full width of the furnace-building, and extends back into the hill a distance of seventy feet) by two overhead tramways (not shown in the drawings), one on each side. From these the ore-mixture is made up on one side, while it is being taken to the furnace from the other. The fuel also is delivered by these tramways. The fluxes are stored on a floor directly at the back of the boiler and engine room. The boiler is a Cornish one, 6 feet 6 inches in diameter by 25 feet long. Its flue is 3 feet in diameter and does not contain Galloway tubes. The working-pressure is 40 pounds per square inch. The engine is an old-fashioned one, with a cylinder 16 inches in diameter by 30 inches stroke. Both the engine and boiler had been part of the plant of a defunct gold-mining company. They were very extravagant in their consumption of fuel. The blast is supplied by a rotary pressure-blower, of the Baker pattern, made in England. It has a capacity of 60 cubic feet per revolution. The furnace, which has several novel points, is shown in detail in Figs. 1, 2 and 3. The jackets are of cast-iron, and are higher than those generally used. They are different, too, in that the feedwater inlet is through a hand-hole plate near the bottom. This plate is fastened to the jacket by stud-bolts, and is provided with a baffleplate, which prevents the cooling water from impinging against the inner plate. The outlet is by a goose-neck at the top, which dis-

Jan 1, 1893

By T. R. Ingraham

The thermal decomposition of cupric sulfate and of cupric oxysulfate has been examined by deter-mining the equilibrium gas pressure generated over each pure compound. The equilibrium data have been used to calculate the thermodynamic properties of both compounds, and the results have been combined with previously published data to establish a predominance-volume diagram for the Cu-S-O system over the normal range of roasting temperature and gas composition used in the treatment of copper minerals. Copper oxysulfate recrystal-lizes at 1100°K with an apparently irreversible en-dothermic heat requirement of 2.9 * 0.3 kcal per mole. WHEN mixed sulfide minerals containing copper are roasted, either of two procedures may be followed, depending on the nature of the other metals. In the first procedure, the roasting is controlled to produce a maximum amount of water-soluble copper sulfate which may be removed selectively from the water-insoluble compounds of the other metals. In the second, control is directed toward the production of water-soluble sulfates of the other metals and an insoluble salt of copper. Effective control of either of these processes would be enhanced by knowledge of the thermal stability of cupric sulfate and of cupric oxysulfate. In this paper, established data for the thermal stability of cuprous and cupric sulfide and of cuprous and cupric oxide will be combined with new data for the therma1 stability of cupric sulfate and cupric oxysulfate, to designate the volumes of stability of the significant compounds in the Cu-S-O system in the temperature range 750° to 950°K. EXPERIMENTAL Materials, Apparatus, and Procedure. The copper source material used in all experiments was Fisher Certified Reagent Grade "anhydrous" cupric sulfate, for which the following analysis was supplied by the manufacturer: chloride, 0.002 pct; alkalies and earths, 0.2 pct; insoluble, 0.002 pct; iron, 0.020 pct. Cupric oxysulfate was prepared from the normal sulfate by two procedures. In the first, equimolar quantities of cupric oxide (prepared by decomposition of the sulfate) and cupric sulfate were ground together and heated under vacuum in a sealed silica vessel at 800°C. This procedure was subject to failure because of explosion of the silica vessels due to the pressure of the final traces of water released from the sulfate on the initiation of its decomposition. The second procedure involved roasting the cupric sulfate, with frequent rabbling, in a muffle furnace at 725°C for a period of 48 hr. This produced an excellent product, which was confirmed as copper oxysulfate by X-ray and chemical analyses. The experimental technique used was that of measuring the total pressure exerted by the sulfur trioxide, sulfur dioxide, and oxygen produced by the following reactions: 2 CuS04 = cuo • CuSO4 + SO3 [1] cuo . CuSO4 = 2 cuo + SO3 [2] SO3= SO2 + 1/2 O2 [3] The apparatus used in the experiments has been described previously.1-3 Its main feature of a U-tube mercury manometer in which the mercury is protected from corrosion by enclosure in a flexible Pyrex bellows. Before beginning a run, the interior of the apparatus, including the bellows-manometer and all connecting tubing, was thoroughly washed with hydrochloric acid and distilled water to remove any

Jan 1, 1965

By C. Zener

HE present paper has its origin in an attempt A by the author, extending over the last several years, to understand the influence of the magnetic properties of the constituent atoms upon the various properties of metals and alloys. During this study the author has been impressed by the important role which magnetism plays in the many facets of metallurgy. In writing this paper he has attempted to convey to his colleagues some concept as to the role magnetism will play in the future development of metallurgy. In some of the subjects herein discussed, such as the influence of magnetism upon phase boundaries and upon mechanical properties, only general thermodynamical properties associated with ferromagnetism are introduced. For these subjects, it is not anticipated that any serious differences of opinion will be encountered. A discussion of the other subjects requires the adoption of a quite specific model of the magnetic structure of the metal. This model is discussed under "Magnetic Shells and Their Interactions." The simple model adopted in this paper has been criticized' as being mathematically inconsistent. This criticism has been ably silenced by Dr. W. J. Carr' of this laboratory. The simple model adopted in this paper has been criticized as being inconsistent with observations on magnetic structure using neutron diffraction. This apparent discrepancy has been resolved by Bader3 who has shown that the finite velocity of neutrons prevents neutron beams from detecting the anti-ferromagnetic structure of the type predicted by the simple model adopted in this paper. Magnetic Shells and Their Interactions An electronic shell of an atom is specified by two symbols.' The first symbol is a number and denotes the total quantum number of the shell. The second symbol is a letter and denotes the orbital angular momentum of each electron within the shell. The letters s, p, d, f are used to denote an orbital angular momentum of 0, 1, 2, 3, respectively, in units of h/2a, where h is Planck's constant. As we pass from scandium to nickel in the first transition period, we eraduallv fill the 3d shell. This shell is responsible for ferromagnetism and hence may be called the magnetic shell. The component of the orbital angular momentum along some specified direction must be an integral multiple of h/2~. Thus, for a d electron this component can have any one of the values —2, —1, 0, 1, 2 times h/2a. In addition to its orbital angular momentum, each electron has an intrinsic angular momentum, hereafter called spin, due to a rotation about its own axis. This spin can have either of two components + Yz (h/2a) or — Yz (h/2~) along the specified direction. A fundamental principle of atomic structure, known as Pauli's exclusion principle, is that no two electrons in a given shell may have identical components of orbital angular momentum simultaneous with identical components of spin. The 3d shell thus may have at most ten electrons. Since an intrinsic angular momentum of a charged particle is necessarily associated with a magnetic moment, the spin of an electron may be thought of as referring to either this angular momentum or to the associated magnetic moment. The electron configuration of the ground state of the isolated atoms in the first transition row is reproduced in Table I. The superscript represents the number of electrons in each shell. For the purpose of this paper, the most important principle of atomic structure relates to the manner in which electrons are added to a shell as the atomic number is increased. This principle, commonly known as the principle of highest multiplicity or more simply as Hund's rule, states that within a given shell the maximum number of electrons have spins pointing in the same direction as is consistent with Pauli's exclusion principle. An application of this principle to the d shell is illustrated in Fig. 1, where the spin structure is given for shells containing from 1 to 10 electrons. The physical basis of Hund's rule is the exchange energy discussed first by Heisenberg in 1928. This is a coupling between electrons with parallel spins (spins pointing in the same direction), the coupling

Jan 1, 1956

By Kim Beattie

IN spite of the fact that in 1944 Canada experienced a decline in production of all her leading base metals-nickel, zinc, lead, and copper; despite uncured headaches in the coal-mining industry; and cheerfully ignoring a still further drop in gold, the most valuable product of her mines, which had the lowest output of any year since 1931, the Canadian miner retains the traditional optimism of miners everywhere as he looks forward to the postwar period. Some factors should keep the Canadian mining industry from being too optimistic of the coming era of peace, but the fraternity generally holds that its confident attitude towards the future is based on sound reasons. The decline in production in the Canadian mining industry last year can be almost wholly attributed to the serious shortage of labor and the difficulty in obtaining transport and supplies in remote areas. Some falling off occurred in the demand for certain strategic metals, but the diversion of gold miners, especially, without replacements being obtainable, to direct war work or allied pursuits, was certainly the principal cause of the reduced output in 1944. But that is a situation which will right itself at the close of the conflict.

Jan 1, 1945

By R. F. Rolsten

VAN Arkel 1 prepared ductile tantalum by the thermal decompoiition of tantalum pentachloride on a resistively heated wire (2000° C) in an evacuated bulb maintained at 100°C. Burgers and Basart2'3 observed the formation of a mixture of tantalum carbide and free metal when a carbon deposition base was used. campbel14 suggested the thermal decomposition of the iodide if a lower decomposition tem- perature was desired. To date, the details for preparing high-purity iodide tantalum have not been disclosed. EXPERIMENTAL The tantalum to be purified was symmetrically placed around the clear quartz deposition surface centrally located within a 64 mm cylindrical Vycor bulb. The deposition vessel usually employed5 was modified6 by incorporating a reentrant fin,mer in place of the customary metal filament in the head

Jan 1, 1960

By G. H. Anderson

H. R. HANLEY*—I have been asked to discuss briefly the development of rotating cathodes for the electrolytic deposition of cadmium. The earliest recorded use of rotating cathodes was by Hoepfner at Frufurt, Germany about sixty years ago. He elec-trolized zinc chloride solution using diaphragms to separate electrodes. In the early experimental work of the Bully Hill Copper Mining and Smelting Co., Shasta County, Calif., rotating aluminum cathodes 4 ft in diam were used in the electrolysis of an acid zinc sulphate solution. Finished cathodes weighing up to 400 lb were produced. Because of mechanical difficulties, this type of cathode was abandoned for zinc, but was later used for cadmium because of the relative smoothness of deposit in comparison with stationary plates with comparable current densities. Cadmium sponge which forms on the cathode at moderate current densities (without special treatment) is entirely eliminated by a slow rotation. The rate of rotation of the cathode has an effect on the mechanical nature of the deposit. A high rate of rotation concentrates the adhering electrolyte on the shaft; a moderate rate appears to concentrate on the cathode a short distance out from the shaft tending to corrode the deposit in the form of a ring. At a very slow rotation (2 to 3 rpm) the adhering electrolyte gravitates nearly vertically, thus avoiding the cutting ring referred to above. The true explanation for the smoother deposits obtained on rotating cathodes may not be given definitely as the numerous factors involved are not thoroughly understood. Smooth deposits are obtained when the orderly growth of the metal crystals in the cathode lattice are disorganized. Thus the crystals form and grow for a very short interval when they are arrested and a new crystal forms. The continued growth of the original crystals provides large crystals and a rough deposit. Also if the acidity of the electrolyte is low, hydrogen gas bubbles adhere to the deposit. As the cathode is rotated the gas surface is brought into the atmosphere where they burst; thus the deposit is made on a surface relatively gas-free. An aluminum hub distance piece was riveted to each aluminum disk 4 ft in diam, slipped on a 4 1/2 in. steel shaft and pressed tight to prevent acid electrolyte seeping through to the shaft. The 9-cathode assembly was supported on insulated bearings. Electrical contact to the shaft was made through what was equivalent to a copper pulley. Sufficiently high conductivity brushes were placed on the face of the pulley to lead the current to the cathode bus bar. The assembly was driven by a link belt contacting a sprocket insulated from the shaft. The lead anodes were semicircular and supported on porcelain insulators placed on the bottom of the cell. Two anodes were provided for each cathode to permit an 8-in. space between them without increasing the ohmic resistance. This ample spacing permitted easy stripping of deposit with the assembly in place. Cathode cadmium was melted under 650 W cylinder oil. After casting, the primary slabs were remelted under molten caustic soda and cast into pencils 1 1/32 in. in diam. Rotating cathodes for deposition of cadmium are used at Risdon, Tasmania, and at Magdeburg, Germany. W. G. WOOLF*—This paper is very-interesting to me because in our work at the Electrolytic Zinc Plant of the Sullivan Mining Co. we had an exactly similar problem—that is, a method of producing cadmium from our purification residue, the recovery of the contained copper as a copper precipitate which could be sent to a copper smelter and the production of merchantable cadmium. It is interesting to me, not knowing of the work of the Risdon people, how closely we approximate them in their main metallurgy, diverging at several interesting steps which I would like to discuss for just a moment. For example, at Risdon they oxidize their purification residue. In our practice we take the current residue as it is produced in the purification department of the zinc plant and process it in the cadmium plant. The only oxidation that it obtains is the oxidation in the presses, the dumping of the presses and the collection and transportation of the residue to the cadmium plant. We find that the leaching of that residue does not necessarily require the oxidation step that the Risdon people evidently find necessary. The discussion of oxidation comes in again in the matter of the treatment of the precipitated cadmium sponge with zinc dust which again at Risdon is oxidized but which we do not attempt to oxidize except as it oxidizes itself in the storage. There is a partial oxidation which cannot be avoided, as Mr. David-sou pointed out, but we make no attempt to attain a complete oxidation and we dissolve the cadmium sponge in the sul-

Jan 1, 1950

By K. Nassau

The Effect of tin and hydrogen on the C0 parameter of a titanium. specimens were capsule cooled in water to eliminate contamination by water. Deybe-Scherrer photograms were obtained in a 114.6 mm camera with CuKa radiation. The parameters shown in Table I and Fig. 1 were calculated from the 213 (8569°) and 302 (8173.5°) reflections? no attempt being made to correct for systematic errors. The principal difference in method of preparation of specimens between this investigation and that of Worner was the use of pickling by the latter to produce X-ray diffraction samples. The possibility that hydrogen introduced by pickling was responsible for the lower a and c-parameters was investigated with the same 80 pct HNO3- 20 pct HF solutions used by Worner. The 6 and 10 at. pct specimens, the parameters of which had already been determined, were pickled and the c-parameters obtained are also shown in Fig. 1. The a-parameters, not shown, are also diminished. The quality of the lines obtained from the unetched and etched samples was unchanged, being quite sharp in both cases. It is quite possible that if corrections for systematic error carried out that the parameters obtained for the unetched samples would approach the data of Worner. In any event, the parameters of the etched samples would be still lower. The data obtained here is evidence that hydrogen in solution has contracted the c and a -parameters. Crystallographic Angles of Calcium Tung-state (Tetragonal, c/a = 2.169) K. Nassau In connection with the preparation and orientation of single crystals of calcium tungstate (Scheelite -CaWO4), the need arose for a stereographic projection for this tetragonal material. There appear to be no tetragonal projections with a c/a ratio above that of indium1 (c/a = 1.522) in the literature. In addition to its use for calcium tungstate, such a projection might find other more general applications and is accordingly presented below. The most recent X-ray diffraction work on CaWO4 is that of Swanson, Gilfrich, and Cook,2 where a summary of previous work is also found. Lattice parameters given are: a = 5.242A, c = 11.372A, and c/a = 2.169. The material is tetragonal with space group Table I, giving angles between crystallographic planes (HKL) and (hkl), was calculated from the formula3

Jan 1, 1961

MINING ASSOCIATION OF UNIVERSITY OF CALIFORNIA At a meeting of the Mining Association of the University of California, held May 22, .the .following officers were elected for the fall, semester: President, Sam Grinsfelder; vice-president, Marcus. Peterson; secretary, Ferdinand Trescher; treasurer, Carlton Hulin. F. G. TRESCHER, Secretary.

Jan 8, 1919

Established as a Division March 24, 1922 R B Gilmore, '57, Chairman G L Yates, '56, Vice-Chairman Phil J Lehnhard, '56, Vice-Chairman John R McMillan, Past Chairman T A Pollard, Treasurer Joe B Alford, Executive Secretary 800 Fidelity Union Building Dallas 1, Texas

Jan 1, 1955

By W. L. Falke, A. A. Cochran

Vast deposits of low-grade manganese ore exist in the United States, yet domestic production is insignificant compared to the more than 2 million tons of ore imported yearly into this country.1 A basic problem in connection with manganese is to find economical ways to utilize domestic resources.2 As a part of its program to conserve domestic mineral resources and to reduce dependence on foreign sources, the U.S. Bureau of Mines has conducted extensive research to broaden manganese technology and to find economical processes for recovering manganese from these low-grade resources. Although a great many processes have been proposed for treating domestic manganese resources, a failing of many of them is that too many steps are involved for economical operation.2 Some of the major processes that have been proposed were reviewed by Norman and Kirby.3,4

Jan 3, 1967

By R. B. Adamson

The fatigue behauior of irradiated copper single crystals is compared to that of unirradiated crystals. Proton or electron irradiation did not substantially change the fatigue-lzj.e, fatigue-hardening-, or slip-line characteristics, while neutron irradiation did appear to alter these parameters. Postfatigue transrrzission electron microscopy did not reveal any marked structural differazces between irradiated and unirradiated specimens. Possible dislocatio~a mechanisnzs to explain the observed behavior are discussed. A LTHOUGH considerable work has been done to ascertain the effects of radiation on the tensile properties of metals (e.g., Refs. 1 and 2), little work of a basic nature has been reported on the effect of radiation on fatigue properties. Since it is known that fatigue properties are sensitive to conditions at the surface of the metal, it was felt that charged particle irradiation, whose penetration into metals is very small, might influence the fatigue behavior. To investigate this surface effect, irradiations with 10 mev protons and 1.5 mev electrons were conducted. The range of 10 mev protons in copper is about 0.236 mm; which is very small compared with the thickness of the specimens used (1.53 mm). The range of 1.5 mev electrons is somewhat larger, on the order of 0.665 mm.4 On the other hand, irradiation with reactor neutrons produces damage throughout the entire specimen, so neutron irradiation can be used to study the effects of bulk damage. The damage introduced by proton and neutron irradiation is expected to con!ist of large interstitial dislocation loops,5 tiny (<25A) vacancy loops," and/or various vacancy-rich regions called depleted zones.&apos; In the case of electron irradiation at about -173°C the damage is expected to consist of isolated Frenkel pairs.&apos; The effect of radiation damage on the fatigue properties of some engineering materials has been reported,g,10 but the results are not clear-cut or consistent. SPECIMEN PREPARATION Zone-refined copper was used to grow single crystals by a modified Bridgeman technique in an inert helium atmosphere. Using a seeding method, single crystals were obtained as bars about 6 in. long with a cross section of 3 by $ in. Immediately upon removal from the split-mold graphite boat in which they were grown, the very soft bars were embedded in a room-temperature setting plastic. They could then be cut into specimen lengths without introducing any long-range damage. Generally, four or five specimens plus one seed were obtained from each bar. The plastic material was dissolved away in acetone and the orientation of each sample was checked by the standard Laue X-ray

Jan 1, 1968

By H. J. O’Donnell, B. C. Parks

IN 1930 the late Dr. Reinhardt Thiessen set up a method of microscopic analysis and type classification of coal that has since been followed as standard practice in the coal-petrography laboratory of the Bureau of Mines. Thiessen&apos;s terminology which designated the constituent parts of coal in terms of botanical origin was introduced in 1920.l The technique, however, of preparing a completely representative series of thin sections from a column sample of coal for use in making quantitative determinations of coal components with a microscope was developed about 10 years later by Thiessen and coworkers G. C. Sprunk and H. J. O&apos;Donnell.2 Complete thin-section analyses subsequently have been made of 126 column samples of various ranks and types of American coals. The data and information were assembled from these thin-section studies and published in a large number of reports dealing chiefly with investigations of the coking and hydrogenation properties of certain American coals. In the years following adoption of Thiessen&apos;s method, a considerable amount of work was done in collecting column samples of many coals, making routine thin-section analyses of these, interpreting the results, and finding practical application for the information in other fields of coal research. The many reports and papers covering the work in coal petrography, however, offer very little discussion that can be considered as critical appraisal of the technique. Criticism outside the Bureau most often has voiced questioning opinions concerning the accuracy of the method used of measuring coal components microscopically and classifying the coal into arbitrary types on the basis of the quantitative determinations. The principal purpose of this paper is to discuss in some detail and present data showing the results of certain investigative work done in the petrography laboratory on the accuracy of the Bureau&apos;s method of microscopic measurement of components in coal thin sections. Data from microscopic analyses on file made by G. C. Sprunk and H. J. O&apos;Donnell were freely used in the investigation, and a table of columnar analyses from an unpublished manuscript by Sprunk is included in this paper for reference. In the course of the experimental work a method was developed for measuring instrumentally with a planimeter the components shown in micrographs of selected thin sections. Measuring coal components with a planimeter furnished useful information for studying the accuracy of microscopically measuring the same components in thin sections. PETROGRAPHIC COMPONENTS AND TYPE CLASSIFICATION OF COAL Thiessen considered coal to be composed of two visibly different major components present in various types of coal in greatly varying proportions. He named

Jan 1, 1948

By H. J. Donnell, B. C. Parks, O&apos

In 1930 the late Dr. Reinhardt Thiessen set up a method of microscopic analysis and type classification of coal that has since been followed as standard practice in the coal-petrography laboratory of the Bureau of Mines. Thiessen&apos;s terminology which designated the constituent parts of coal in terms of botanical origin was introduced in 1920.1 The technique, however, of preparing a completely representative series of thin sections from a column sample of coal for use in making quantitative determinations of coal components with a microscope was developed about 10 years later by Thiessen and coworkers G. C. Sprunk and H. J. O&apos;Donnell.2 Complete thin-section analyses subsequently have been made of 126 column samples of various ranks and types of American coals. The data and information were assembled from these thin-section studies and published in a large number of reports dealing chiefly with investigations of the coking and hydrogena-tion properties of certain American coals. In the years following adoption of Thies-sen&apos;s method, a considerable amount of work was done in collecting column samples of many coals, making routine thin-section analyses of these, interpreting the results, and finding practical application for the information in other fields of coal research. The many reports and papers covering the work in coal petrography, however, offer very little discussion that can be considered as critical appraisal of the technique. Criticism outside the Bureau most often has voiced questioning opinions concerning the accuracy of the method used of measuring coal components microscopically and classifying the coal into arbitrary types on the basis of the quantitative determinations. The principal purpose of this paper is to discuss in some detail and present data showing the results of certain investigative work done in the petrography laboratory on the accuracy of the Bureau&apos;s method of microscopic measurement of components in coal thin sections. Data from microscopic analyses on file made by G. C. Sprunk and H. J. O&apos;Donnell were freely used in the investigation, and a table of columnar analyses from an unpublished manuscript by Sprunk is included in this paper for reference. In the course of the experimental work a method was developed for measuring in-strumentally with a planimeter the components shown in micrographs of selected thin sections. Measuring coal components with a planimeter furnished useful information for studying the accuracy of microscopically measuring the same components in thin sections. Petrographic Components and Type Classification of Coal Thiessen considered coal to be composed of two visibly different major components present in various types of coal in greatly varying proportions. He named

Jan 1, 1949

By M. C. Flemings, A. A. Tzavaras

Analytical and experimental procedures are descrihed for quantitative determination of volume-fraction microporosity in metals by mimorarlio-graphg. The analysis assumes spherical pores but allows for the observed fact that pores or portions of pores smaller than a given thickness do not project an image on the film. Volume-fraction microporosity was measuured in cast low-alloy steel and shown to vary from 0.6 x 10-4 to 10 x 10 depending on mode of solidification and on whether the material was air- or vacuum-cast. The aim of work described herein was to develop a method of quantitative measurement of the volume fraction of microporosity in cast metals. Microporosity, present in nearly all castings and ingots, is always interdendritic in nature and may be large enough to be seen on a polished surface with the naked eye. More generally, it is smaller in size, and its detection more difficult. Three techniques might be considered for measurement of microporosity: 1) lineal analysis of a polished metallographic surface, 2) density measurement, or 3) quantitative microradiography. As will be shown later, volume fractions of porosity in directionally solidified castings may be the order of 10-4 to 10-3; such small amounts of porosity are difficult to identify and measure on a polished surface. Density measurement is also not a suitable technique (for alloys) when the volume fraction of porosity is low. This is because the density of the base metal is often not known within the necessary accuracy, due to microsegregation or partial phase transformations. In general, it is not possible to completely eliminate microsegregation without also altering the porosity. Because of the limitations of the foregoing techniques, quantitative microradiography was employed to determine amount of porosity. In recent work, microradiography has been found to be useful for qualitative measurement of porosity, including determination of size and shape of individual pores;&apos;)&apos; however, quantitative determination of amount of porosity has not been attempted. I) CALCULATION OF VOLUME-FRACTION POROSITY The following analysis employs procedures similar to those of Cahn and Nutting3 and Hilliard.4 Major simplifications are that pores are assumed to be spherical and to be present in sufficiently small quantities that no overlapping occurs. A basic difference from the previous treatments is that the limited "sensitivity" of microradiography is considered. Assume first 1) cavities are spherical and of uniform diameter, 2) cavities are randomly distributed, 3) volume-fraction porosity and specimen thickness to pore radius ratio are sufficiently small that overlapping of the projected images of cavities is negligible, 4) sensitivity is limited (i.e., holes or portions of holes of less than a given thickness do not project an image on the film). The sensitivity, is defined as: where 5 = minimum thickness of void from which an image will be projected on the film and t = specimen thickness. Now, from Fig. 1, it is possible to distinguish between two different types of holes. These are 1) holes whose centers lie within the region t/2 > X > 6/2, where X is distance from one surface of the specimen (positive into the specimen), and 2) holes whose centers lie within the region (6 — r) < X < 6/2, Holes whose centers lie outside X = (6 -r) project no image on the film. These two types of pores are considered separately below. Type 1 Pores. When 6 is greater than 0, the image of a spherical cavity of radius r appears on the film as a circle of radius a which is smaller than r. From geometry, Fig. 1: a2=r2-52/4 [2] where a = radius of image of pore on film and r = radius of pore. Since the pores are randomly distributed and spherical V =4/3pr2Nv [3] where V = volume fraction of voids and Nv = number of pores per unit volume and the number of images of Type 1 pores per unit area of film, N&apos;A, is

Jan 1, 1965

Discussion of the paper of HOWARD N. EAVENSON, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October,&apos; 1914, pp. 2637 to 2660. GEORGE S. RICE, Pittsburgh, Pa.-I think it is very wise to point out the greater liability to explosions in certain parts of the year, if there be such difference, with the caution, however, that vigilance be not relaxed at other times. In comparing the figures for the United States with those of Europe, I think we should separate them as far as possible according to cause of origin and means of propagation. That is to say, it would appear to me that the majority of our explosions are due more directly to the ignition of coal dust directly from the flame of explosives, whereas, judging from my inquiries and observations in some of the mines of Europe, the majority of their explosions have been caused by the ignition of fire damp. Now, in the case of fire damp, I do not think that anybody has yet attempted or has been able to find any connection between the seasons and the issuance of methane into mines. One thing must be borne in mind, that if you get a strong explosion of fire damp, dust of a character that might not ignite readily by itself might assist in the extension of an explosion of fire damp through a considerable area in the mine, if not throughout the mine. While it is true we have many lesser explosions in this country attributable to fire damp, it would appear that the majority of all the mine explosions of the country, in considering the means of propagation beyond the locality of the origin, are due to coal dust; and it is the liability to coal-dust explosions that appears to be affected by seasonal changes. Hence the desirability of separating statistically (if it could be done by the inspectors) fire-damp explosions from coal-dust explosions, in order to obtain the true value of the seasonal effect. Nevertheless, in spite of the inclusion of fire-damp explosions with coal-dust explosions, the preponderance of the evidence, as indicated in Mr. Eavenson&apos;s figures for American mines, has shown that&apos; in this country there were more explosions in the winter and spring months, when the mines are drier; that is, when the mines are apt to be drier. Whereas, according to the European figures that he has gathered, it seems to be very clearly demonstrated that in France, England, and Belgium, the time when explosions occur has no connection with any particular season. That, I think, is partly due to the point just mentioned, that a majority of their explosions have originated from fire damp. The European mining men have been more careful, generally speaking, with the use of explosives than we have, so that the cause of ignition from that source has been less. Only comparatively few of the mines in foreign

Jan 4, 1915