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By N. K. Chen, C. H. Mathewson

Recrystallization of aluminum single crystals after plastic extension is carefully studied in relation to the structure of the deformed matrix. The shapes of the new grains are analyzed with regard to slip planes and to the presence or absence of deformation bands. A mechanism by which the orientations of the grains are related to the parent lattice is described. EXPERIMENTS previously reported&apos; have been extended to develop some of the characteristics of the new crystals which are formed on annealing axially strained crystals whose deformational characteristics had been documented with special care. Thus, the presence of deformation bands affects the growth contours of the crystals, some of the strained crystals produced single crystals anew, and some, polycrystals, on annealing, while others merely "recovered" or "polygonalized" after the 600°C annealing treatment generally adopted in these tests. In the matter of orientational relationships between new crystals and the strained matrix, the present experiments have added little to previous experience, which had demonstrated great variety in the range of orientations encountered and no simple theory or correlation. For example, there has been ample evidence for the predominance in various face-centered cubic metals of a favored orientational relationship; viz., a rotation of 30° to 40° around a <1ll> axis, between grains growing in a matrix with a strong single orientation texture and the matrix itself.&apos;-&apos; This reorientation has been interpreted by various investigators in support of both the "oriented nucleation" and the "oriented growth" hypothesis. In the case of axially extended single crystals of aluminum, no general relationship, such as the one stated above, can be used to correlate the orientations of the recrystallized grains with that of the original crystal. Thus, Carpenter and Elama and Burgers and Basart7 were content to assume that the orientational relationships so developed were random in nature. Mathewson, however, in the Campbell Lecture of 1943 "rgued on the basis of <112> slip that a complex strain, chiefly characterized by rotation around a variable axis in the slip plane combined with a principal rotation around the pole of the slip plane, could be responsible for such devious relationships. Nevertheless, owing to the limited data now available dealing with orientational relationships between new grains and the single crystals strained in tension from which they have recrystallized, no adequate examination of the above generalization could be made. Here, there is the disturbing preliminary condition that any desired orientational relationship may be expressed by means of two rotations about mutually perpendicular axes, so the process lacks a certain critical flavor and any successful choice of axes meeting certain theoretical requirements could be replaced by another differently selected pair. With this reservation clearly in mind the process of double rotations, as previously indicated, was used to relate the orientations of the single crystals which grew out of the strained single crystalline matrix and was construed as certain evidence in favor of the theory of incongruent shearing action proposed by Mathewsons as a necessary element in the (111) slip process with close-packed metals. There is here

Jan 1, 1953

ONE DAY IN the mid-1880s, in a suburb 0f Pittsburgh, Pennsylvania, there dismounted from a train the two foremost leaders of the day in the coal and steel industries-Andrew Carnegie and H. C. Frick. Their attention was drawn to a well-loaded car of coke, which their experienced eyes recognized as a superior product. "I&apos;ll bet you that coke is from the H. C. Frick Coke Company," Mr. Frick challenged. "I&apos;ll bet it was shipped by my company." In a spirit of fun Mr. Carnegie accepted the wager. Mr. Frick lost the bet: the coke had come from M0rewood, one of three sites being operated under the direction of a young entrepreneur, Erskine Ramsay. If Mr. Frick&apos;s confidence was somewhat dented by this occurrence, the responsibility was his own. He himself had opened the way for Erskine Ramsay to become the youngest of mine superintendents; and he had dispersed all dissension regarding his choice with the words : "I&apos;m not interested in his years, I&apos;m interested in his record. He makes more coke in an oven than any other superintendent. And I&apos;ll take &apos;em out 0f the cradle if they can make coke... Suppose he is only twenty years old? ... The d --- kid is a genius, I tell you." Erskine Ramsay was to follow in the tradition of Carnegie and Frick. Not only was he ambitious and a worker his background had prepared him for it. Coal mining was in the Ramsay blood. His father, Robert Ramsay, of whom the son once stated that he had no superior as coal mining and mechanical engineer in this country, once accounted in these words for the phenomenal accomplishments which had attached to the name "It does no harm to belong to a family of mining engineers who are just as good as any in America-if it is myself that says it." Anyone acquainted with Robert Ramsay&apos;s character realized that he was not given to overstatement. And the above-mentioned Mr. Carnegie encountered young Ramsay again, a few years later in his career, and wrote of him to young Erskine&apos;s father, that he was "going to be a credit `tae us a&apos; " (a quotation from Robert Burns.) Nor have Mr. Ramsay&apos;s achievements been identified exclusively with the industrial field in which he early asserted himself. He has been an inventor whose techniques in mining engineering have received international recognition. As an investor of foresight, he has benefitted others immeasurably, as well as himself, being an influential factor in the upbuilding of several communities in his chosen and well-loved adopted home state of Alabama since 1887. He is a philanthropist whose benefactions have run into millions, the chief beneficiaries being educational and charitable institutions. Amidst his accomplishments the lighter side of life has not been neglected and he is known for his hospitality, his

Jan 1, 1953

By L. G. Truby

DISCUSSION By Rhrt G. Nisle, Phillips Petroleum Co., Barthesville, Okla. The subject paper presents the results of a reservoir behavior analyzer study of the pressure-production performance of five Ellenburger pools in West Texas. These five pools are Wheeler, TXL, Andector, Embar, and Martin. This laboratory has also made reservoir behavior analyzer studies in this area and arrived at substantially the same conclusions. Although the principal results of the studies made in this laboratory are confirmed by the results in the subject paper, there are certain points of difference. The points of difference are (1) the subject paper includes the Martin pool in the common aquifer, whereas our studies indicate that it is not, and (2) the subject paper concludes that the effective aquifer is considerably smaller than that derived from studies made in this laboratory. In terms of reservoir analyzer data, our rejection of Martin is based on the inability to obtain a satisfactory match of the pressure curve when Martin is considered as lying within the common aquifer. A satisfactory match was possible, however, when Martin was run as an isolated pool. This indicates that the pressure disturbance resulting from production at Martin had not reached Embar, Andector, TXL, or Wheeler at the time of our study. A similar situation exists relative to Dollarhide. In tern of geological data, our rejection of Martin is based on the presence of a faulted zone between Martin and Embar. This condition is indicated in Fig. 4 and again in Fig. 10 of the subject report. If a permeable connection between Martin and the other fields does exist, it is probably by way of a detour around this fault. The second point of difference between the two studies is illustrated by a comparison of Fig. 4 of the subject paper with Eg. A. Fig. A is obtained from an internal report on one of the studies made by this laboratory. It will be noted that the area indicated in Fig. 4 is roughly that marked "Pool Unit" in Fig. A. The additional portion of the aquifer shown in Fig. A was simulated on the reservoir analyzer by means of the water drive network. A satisfactory pressure match could not be obtained without this additional network. The differences involved here stem from a more fundamental consideration concerning reservoir analyzer operating techniques. The true source of these differences in reported results cannot at this time be determined because of the incompleteness of the subject paper. It is not stated, for instance, whether the pressure match was induced by altering the field resistance or the field capacitance, or both. Changing analyzer

Jan 1, 1953

By B. L. Dunic, Terkel Rosenqvist

rr has long been suspected that sulphur has a small but finite solid solubility in iron, but up to the present more accurate data have been lacking. The survey given by Hansen&apos; illustrates the divergence of data and opinions. Solubilities between 0.01 and 1.5 pct have been suggested, and opinions vary regarding the effects of temperature and phase transformations in iron on the sulphur solubility. The extent of solid solution and its variation with temperature might be expected to be an important factor in the occurrence of hot shortness in steel. Therefore, the object of the present investigation was to study this problem more systematically. It was furthermore hoped that solubility data for sulphur might contribute to an understanding of the factors which determine solid solubilities in general. Experimental Procedure The present work was based on the measurement of the chemical activity of sulphur in the solid solution by means of equilibrium with a mixture of hydrogen and hydrogen sulphide. When the solid solubility limit is reached, the sulphur activity in the iron becomes equal to that in the coexisting sulphide phase. A gas mixture of a controlled H,S/H, ratio was passed over pure metallic iron heated to a temperature in the range 900" to 1500". The amount of sulphur absorbed by the iron was determined by analysis, and from a plot of percentage of sulphur vs. gas composition the sulphur activity and the solubility limit were determined. As the rate of diffusion of sulphur in solid iron is very small, often several days were needed to be sure that equilibrium conditions had been established. To produce a gas flow with less than 1 pct H,S of constant composition for several days, was in itself a problem. The most satisfactory arrangement was obtained by a continuous synthesis of hydrogen sulphide from the elements. This was done in the part of the apparatus shown to the left in Fig. 1. The hydrogen used was first purified in tank batches by passage through activated charcoal cooled in liquid nitrogen under a pressure of 150

Jan 1, 1953

By J. W. Snavely

A practical mathematical treatment is presented for the determination and control of conveyor belt acceleration, particularly for conditions of starting where vertical curves are involved. A typical sample problem is analyzed, with required calculations, to clarify the procedure. THE part that acceleration plays in starting a belt conveyor and its effect on belt conveyor design are well understood in a general way. Its practical importance is easily overlooked, however, and under some conditions, it is absolutely necessary to give the problem of acceleration detailed study. Most handbooks on conveyor belting design adequately present basic data for the determination of acceleration values. This paper will only attempt to present practical thinking and a convenient method of treatment of acceleration in belt conveyor design. Mathematical Analysis In working out the various problems of conveyor belt acceleration, the starting point, as presented by the handbooks, is the familiar formula of "force of acceleration is equal to the mass times acceleration." By expressing these fundamental quantities in terms of belt conveyor design, it is possible to arrive at the unsuspected conclusion that the acceleration time for horizontal belt conveyors is independent of the load, and instead, dependent upon the belt speed, the type of drive arrangement and drive pulley, and the idler coefficient of friction. The mathematics leading to this conclusion are shown in Table I, which has been prepared to show this derivation. While at first the conclusion just given may not seem to be reasonable, further reflection indicates that obviously the type of drive pulley and the type of drive do affect materially the tension in the conveyor belt, and thus, as clearly shown, the time of acceleration is dependent upon the factors mentioned. Inasmuch as all of the factors except time are predetermined by the belt conveyor design, it becomes relatively easy to establish the accelerating time and to reduce further this time determination to a simple graph from which the time in seconds can be read directly. Such a graph is given in Fig. 1. The table appearing on Fig. 1 should be explained further. For a given belt speed, the time of acceleration can be expressed as a percentage of the belt speed. The time of acceleration is also dependent on the drive arrangement, and changes in the drive arrangement consequently change the time of acceleration. It further follows that for a given belt speed, the time expressed as a percentage of that belt speed also changes with the type of drive. Obviously then, it becomes possible to graph the percentage of speed for .each type of drive against the belt speed and accelerating time, after which, for a given belt speed and type of drive, the time can be read directly in seconds. Two constants were established for Fig. 1, the first one being the limiting of the maximum acceleration tension to 35 pct of the full load operating tension in the belt. The purpose of this is to limit the total tension imposed upon the belt during the acceleration period to 135 pct of the full load operating tension, &apos;which is the amount required to start or breakaway the fully loaded belt conveyor from rest. The other constant is the friction factor used for the idler equipment, which has been established as 0.022. For installations where it is necessary to establish the values of acceleration, invariably high grade idler equipment is used, and it has been established from field experience that 0.022 for the idler friction factor is amply conservative. The use of this friction factor for idlers must be tempered with judgment, of course, for occasions will arise where more power than indicated is required to start, even with the very best of equipment, such as low temperature operations that tend to congeal the grease in the bearings and thus produce additional friction drag. An inspection of the table in Fig. 1 affords a convenient rule of thumb method for determining the acceleration time, which conveniently can be 5 pct of the belt speed in seconds. The 5 pct of belt speed figure is close to the average for most types of drives. In using Fig. 1 it must be emphasized that it applies accurately to horizontal belt conveyors only.

Jan 1, 1953

Jan 1, 1953

Jan 1, 1953

By Edmund M. Wise

NATURE has provided us with many metals, but with few really good ones, and frequently the better metals are the rarer. It is to this circumstance that many physical metallurgists, inventors, and just plain experimenters owe their employment, for much of their work is directed, consciously or otherwise, toward the alleviation of some of the more serious shortcomings of the cheaper, less noble, and weaker metals; by alloying, age-hardening, passivating, cladding, plating, and other useful dodges, which sometimes permit the substitution of one of the less gifted metals for one of the really good ones. As a matter of fact, the varied needs of our complex civilization could be quite well met with only five metals, if they were sufficiently abundant, and one of the five would certainly be platinum, the most noble and versatile that nature provides. Many metals are difficult to handle and seem to take pleasure in defying their investigators to find good uses for them, and finally when a use is found it is frequently quite a specific one; in other words, a hole has to be found--or perhaps made-to fit the peg. It is for this reason that a large amount of research must be con- ducted before the more recalcitrant metals become really useful. In platinum, however, we have a metal that inherently possesses so many valuable attributes that it became useful as soon as methods for producing it in massive ductile form were devised, and once its complicated chemical behavior was understood it became principally an aid to research rather than the subject thereof. In recent years, much research has been done to further improve

Jan 1, 1953

By J. L. Taylor, Pol Duwez

THE present knowledge of the Ti-Al system is limited to the portion of the diagram extending from pure aluminum to the intermetallic compound TiAl3&apos; A preliminary investigation of the titanium-rich Ti-A1 alloys revealed that the solubility of aluminum in titanium is quite extensive and that the transformation temperature of titanium is raised by alloying with aluminum. From an X-ray diffraction study of alloys containing up to 75 atomic pct Al (TiAl3), the phase boundaries at 750°C were located as follows: the a titanium solid solution extends from 0 to about 36 atomic pct Al, a two-phase region exists from 36 to 46 atomic pct Al, and an intermediate phase of varying concentration extends from 46 to 62 atomic pct Al. The purpose of the present paper is to describe the crystal structure of this new phase. The alloys were prepared by melting in a helium arc furnace on a water-cooled copper plate, using a furnace essentially the same as that described in ref. 2. The titanium metal was of the iodide type furnished by the New Jersey Zinc Co., and a piece of pure aluminum (99.99 pct) was obtained through the courtesy of the Aluminum Co. of America. After melting, the samples, weighing approximately 5 g, were sealed in evacuated fused silica tubes and homogenized for 4 hr at 1000°C. The specimens were then held for 10 days at 750°C and rapidly cooled to room temperature. Filings were then taken from each sample, sealed in evacuated vials, annealed at 750°C for 4 hr, and rapidly cooled to room temperature by quenching the vials in water. Powder diffraction patterns were obtained with a 14.32 cm diam camera, using K copper radiation filtered through a nickel foil. Structure Determination The X-ray diffraction patterns of the alloys containing 46, 50, 55. 60, and 62 atomic pct Al were identical, except for a slight shift in the positions of the reflections. The alloy containing 55 atomic pct Al was chosen far structure determination. The powder pattern contained 37 reflections and the a, doublets were well resolved in the back-reflection range. The relatively small number of reflections and the sharpness of the pattern were considered as an indication of a simple atomic arrangement in a relatively small unit cell of high symmetry, and an attempt was therefore made to solve the structure without single crystal work. A satisfactory fit was found on a large scale Hull-Davey tetragonal chart for an axial ratio of approximately 1.45. All the reflections were readily indexed and the tentative unit cell dimensions were computed to be a - 2.81 kX, c - 4.07 kX, and c/a = 1.448. The indices (hkl) and the values of d and sin2 A are given in Table I. The agreement between observed and computed sin2 is quite satisfactory. Once the unit cell was known, the details of the structure were readily found. First, it is obvious that the number of atoms per unit cell cannot exceed two, since more than two atoms would lead to a density greater than that of pure titanium. The next logical step is to assume that the two atoms occupy the corner and center of the cell. If this assumption is correct, the structure may be described as follows: space group D1, - P 4/mmm; one titanium atom in a: 000; one aluminum atom in d: 1/2 1/2 1/2: and no extinctions. Assuming this structure to be the correct one. intensities were computed by means of the usual equation: sin2 0 cos 0 where F is the structure factor; 8, the Bragg angle. and p, the multiplicity factor. The calculated values of intensities are compared in Table I with the visually estimated intensities. The agreement is quite satisfactory and the structure is therefore confirmed. The crystal structure of TiAl just described is the same as that of AuCu ordered. The AuCu ordered

Jan 1, 1953

By R. I. Jaffee, R. M. Evans

IN recent years, the interest in liquid metals as heat-transfer media for power plants has been very great. The possibility of the development of nuclear power plants has increased this interest and served as the impetus behind much research on low melting metals and alloys for such purposes. The principal reasons for consideration of liquid metals as heat-transfer media lie in their high thermal conductivity and consequent high heat-transfer coefficients, stability at high temperatures, and the high ranges of temperature possible. The element gallium possesses some of the requisite properties for a heat-transfer liquid. It is a unique material, having a low melting point and a high boiling point. Pure gallium melts at 29.78oC, and suitable alloying will produce a metal which melts below room temperature. The boiling point is about 2000°C. As it is a liquid metal, the heat-transfer characteristics would be good. Gallium is not now readily available, due in part to a lack of uses for the metal. Nevertheless, it is not a rare element, and a sufficient supply of gallium exists to permit its consideration for this use. Since gallium has some promise as a heat-transfer liquid, owing to its unique properties, research on the subject was carried on at Battelle Memorial Institute at the request of the Bureau of Ships, U.S.N. The research had as its objectives the determination of the effect of alloying on the melting point of gallium, and the study of the corrosion of possible container materials. In this research, alloys were found which had significantly lower melting points than pure gallium, but none which simultaneously fulfilled other additional requirements, chiefly the corrosion problem. Neither was it found possible to reduce the melting point of certain otherwise suitable alloys appreciably by small additions of gallium or gallium alloys. The results gave little hope that gallium alloys can be developed which enhance the good properties and minimize the undesirable characteristics of elemental gallium. Thus, gallium now appears less promising than other metallic heat-transfer media. The experimental thermal-analysis techniques used in this work have been described.&apos; Experimental Results As a first approximation, the development of low melting gallium alloys was based on alloying elements suitable for use in a nuclear power plant, which also lowered the melting point of gallium. Information from the literature, summarized in Table I, indicates that. tin, aluminum, and zinc are the only suitable elements which cause a lowering of the melting point of gallium. Indium and silver also lower the melting point of gallium, but are of little interest for use in nuclear power plants. Of the elements reported not to lower the melting point of gallium, there is some ambiguity on the behavior of copper. Weibke3 obtained solidus arrest temperatures of 29°C for Cu-Ga alloys from 60 to 90 pct Ga, 0.8C lower than the generally accepted melting point. This may be the effect of a eutectic close to gallium, or, more likely, the result of impurities, or experimental error. The seven elements listed in Table I whose effects were not known were of potential interest if they lowered the melting point of gallium. Their effects were determined experimentally for this reason. Binary alloys containing nominally 2 pct of each of these elements were prepared in the form of 2-g melts by placing the components in a graphite crucible and holding them in an argon atmosphere at 370°C for 5 hr. These melts were then subjected to thermal analysis. In all cases. the solidus temperature was the melting point of gallium. Since these elements (As, Ca, Ce, Mg. Sb, Si, and T1) did not lower the melting point of gallium, they were not considered further as components of a eutectic-type alloy. Ga-Sn-Zn Alloys Preliminary considerations of this system for low-melting alloys were encouraging. All three binary systems were of the simple eutectic type. The composition and melting points of the eutectics were as follows: Sn-9 pct Zn (199°C), Ga-8 pct Sn (20°C), and Ga-5 pct Zn (25°C). Therefore, the probability of a ternary eutectic was high. For reasons to be discussed later, aluminum could not be used as an alloying constituent, leaving the Ga-Sn-Zn system as the only one of interest for low-melting gallium-

Jan 1, 1953

By J. D. Warne

The ferberite district of Boulder County, Colo., has been an important producer of tungsten since 1900. During World War I, high prices for tungston concontrates resulted in a brief period of intense activity, and the production in 1917 was 2,707 tons of 60 percent W03 concentrates. Production declined thereafter, and in 19.2 the tungsten produced in Boulder County represented about 4 percent of the Nation&apos;s output, being exceeded only by the scheelite production in California, Nevada, and Idaho. Boulder County has boon an important source: of tungsten in the Korean emergency; the present report does not describe this recent activity, as it will be covered by a future publication. Tungsten occurs in small ore shoots of narrow and irregular veins. Most of the ore shoots have been found outcropping on the surface. Core drilling; has been used by the larger operators to explore for new veins and to locate extensions of known veins.

Jan 1, 1953

By H. L. Gilbert, W. W. Stephens

Production of anhydrous zirconium tetrachloride by direct chlor- ination of a zirconium oxide carbon mixture in a silica-brick-lined chlorinator is described. Theory and thermodynamics of reactions are discussed. A pilot-model chlorinator and full-scale production equipment are described and operating data are included. ANHYDROUS zirconium tetrachloride required as a starting material in the Kroll process for production of ductile zirconium has been produced in this country principally by chlorination of the carbide or "carbonitride" made by reduction of zircon sand concentrates with carbon in the arc furnace. This process and the equipment used have been fully described.&apos;.&apos; It is well known that zircon or badde-leyite ores may be chlorinated directly with chlorine in the presence of carbon, and this one-step approach would seem at first glance to be preferable to the two steps involved in the carbide-chloride operation. As previously discussed1 considerations leading to adoption of the longer process were: 1—Chlorination of the carbide proceeds rapidly at temperatures below 500°C, whereas temperatures above 900°C were considered necessary for chlorination of zircon-carbon mixtures. 2—The highly exothermic nature of the carbide-chlorine reaction makes it self-sustaining, while heat must be supplied continuously in direct chlorination of the ore. 3—Silicon was thought to be chlorinated along with zirconium in the direct chlorination of zircon, leading to high chlorine consumption. In production of carbide in the arc furnace, silicon is driven off as silicon monoxide and does not enter the chlorinator. 4—For efficient direct chlorination, the ore must be finely ground and intimately mixed with carbon, and the mixture briquetted. 5—Direct chlorination requires a much larger chlorinator for a given production capacity than chlorination of carbide. Recently it has become necessary to produce large quantities of zirconium metal from a chemically purified zirconium oxide. Since the cost of the latter is high, the relatively high losses encountered in production of carbide in the arc furnace could not be tolerated, and a graphite resistor furnace5 was developed for production of carbide, which was then chlorinated in equipment previously used for chlorinating arc-furnace carbide. This method of operation was quite satisfactory, and losses in the carbid-ing step were minimized. However, operating costs were relatively high, and the process did not lend itself particularly well to large-scale operation because of the multiplicity of small units required and the hand labor needed to load, unload, and maintain the furnaces. To chlorinate the carbide, a vertical-shaft chlorinator was used in which the charge was heated with a central split graphite-rod resistor.&apos; Operation of this chlorinator was somewhat less satisfactory with the resistor furnace carbide than it had been with the arc-furnace carbide due, principally, to the differences in physical properties of the carbide. The arc-furnace carbide is obtained as a fused metallic-appearing mass which can be crushed to -1/4 in. with production of a minimum of fines, whereas the resistor-furnace product is lightly sintered and produces a large proportion of fines in crushing and handling. These fines tend to pack in the chlorinator and promote channeling. which results in poor chlorine efficiency and low capacity. Data based on production of 22,000 lb of chloride from resistor-furnace carbide in this equipment are shown in Table I. Necessity for increasing production of chloride from about 2,000 to 15,000 lb per week led to further investigation of possible methods for direct chlorination of the oxide or oxide-carbon mixtures. Direct chlorination of the pure oxide presents much less difficulty than chlorination of zircon sand or oxide ores. The oxide is easily ground to —200 mesh, and no silica is present to cause excessive consumption of chlorine or contamination of the product. Theoretical Considerations The principal chemical reactions involved in chlorination of mixtures of zirconium oxide and carbon may be written as follows: ½ ZrO2 (c) + C(c) + Cl2(g) = ½ ZrCl,(g) + CO(g) [I] 1/2 ZrO, (c) + CO(g) + Cl2(g) = ½ ZrCl,(g) + CO2(g) 121 ½ ZrO2 (c) + ½ C(C) + Cl2(g) = 1/2 ZrCl4(g) + ½ CO2(g) [3]

Jan 1, 1953

By Helen E. Edwards

The Bureau of Mines is engaged in a systematic evaluation of the thermodynamic properties of combustion gases. These studies are designed to provide basic thermodynamic information of high accuracy facilitating the theoretical study of flame and combustion phenomena. This report is the third of a series3/ presenting results of the study for particular fuel-oxidant systems. The equilibrium composition of the products of combustion and the adiabatic flame temperatures of specified oxyacetylene systems have been computed.

Jan 1, 1953

By John Griffen

THE distinguishing principle of the Tromp process is the use of a medium in the bath which is not stable, i.e., the solids will settle and the density of the medium increases with depth. A medium of uniform density can most easily be effected by agitation or by means which increase the viscosity of the medium. Either of these works against the sharpness of separation of coal from its impurities. The Tromp process grinds the medium solids to relative coarseness, allows them to settle downward in the bath without hindrance, and introduces horizontal currents of medium at intermediate levels between top and bottom of the bath. This prevents any accumulation of particles denser than the upper layer of the medium from which the clean coal is conveyed away or an accumulation of particles lighter than the bottom layer or medium whence the refuse is removed. In a relatively shallow bath making a two-product separation, the intermediate horizontal currents sweep these intermediate gravity materials away to be discharged with the refuse removed by the conveyor. Such a system provides a number of advantages. The gravity of separation can be changed simply by changing the density of the medium without changing particle size of medium solids or other conditions, as would be necessary with a system requiring uniform or stable density throughout the bath. Some installations in Europe separate at 1.40 sp gr on one shift, producing a superclean coal, and on the next shift reclean refuse from dry cleaning units and effect a separation at 1.80 sp gr. Medium solids may be much coarser in size consist, which reduces the viscosity of the medium and promotes its fluidity and in turn the sharpness of separation. Coarser medium solids with a more rapid settling rate are much more easily recoverable from the dilute medium rinsed from the products. The Tromp process is not limited to the use of medium solids having magnetic properties. Instal-

Jan 1, 1953

By I. Fatt

Laboratory relative permeability data on reservoir rock are obtained on samples which are not subjected to overburden pressure during the permeability measurements. These data are then used for calculating the performance characteristics of reservoirs in which the rock is under the pressure of the overburden. Recent observations have shown that the permeability and porosity of reservoir sandstones are decreased by application of overburden pressure. These observations led us to a study of the effect of overburden pressure on the relative permeability characteristics of sandstones. A previous note from this laboratory1 showed that overburden pressure, simulated by applying hydraulic pressure to the outside of a plastic mounted core. caused a reduction in permeability of the core by as much as 50 per cent at 10,000 psig. In a multiphase fluid flow system, the relative permeability at a given saturation will change if the permeability or the effective permeability changes but not if both permeability and effective permeability change by the same ratio. The tests described in this note were made to determine the effect of overburden pressure on permeability and effective gas permeability in the gas-oil system. The gas-oil system was chosen because the available equipment was best suited for studying this system. The resultant data can be applied to other systems of interest because the gas permeability in the gas-oil system is the permeability of the nonwetting phase and, as such, is equivalent to the gas permeability in the gas-oil-water system and to the oil permeability in the oil-water system. EXPERIMENTAL METHOD Cylindrical test plugs, one in. in diameter and one in. long, were cut from sandstone core samples from three different reservoirs. After extraction in toluene, the plugs were mounted in Lucite by conventional core mounting methods.3 The core properties are given in the legend in Fig. 1. The mounted cores were machined to fit the apparatus shown in Fig 4. Air permeabilities as a function of overburden pressure were measured by connecting lines (1) and (2) to a conventional air permeameter. To measure porosity changes as a function of overburden pressure, the lines leading to (1) and (2) and the core were saturated with kerosene; line (1) was capped and a small bore precision calibrated pipet was connected to (2). Changes in pore volume of the core as overburden pressure was applied were noted by reading the amount of kerosene produced into the pipet. To correct for the change in volume of the lines inside the hydraulic cell as a function of pressure, a pressure-vs-volume run was made with a solid Lucite cylinder substituted for the core. The change in volume of the lines was about 10 per cent of the change in pore volume of the core. No correction was needed for the permeability measurements because there was no measurable pressure drop in the lines at the maximum overburden pressure. Relative gas permeabilities were measured by the stationary liquid method described by Osoba, et al.&apos; Gas saturations were obtained by allowing the kerosene from a kerosene saturated core to evaporate out. This procedure was followed

Jan 1, 1953

Launching Platform - Drift Indicator- Stratascope-are components of Carbide and Carbon Chemicals new Mining Machine No. 3.

Jan 1, 1953

By O. A. Carson

"IntroductionTHE ZINC-BASE die casting alloys in common usage contain approximately 4 per cent aluminum as the major alloy element. In addition, they contain about 0.05 per cent Mg .and may• have a small amount .of copper. These are usually the only •elements intentionally present.Small amounts of some impurities have been shown to have a deleterious effect on the properties of these alloys and therefore the impurities are kept low by starting with '99.99%' zinc.The reasons for holding the aluminum content at 4 per cent are not clear. Some statements appear in the literature that higher aluminum increases the brittleness, but probably the chief reason was the relative price of zinc and of aluminum when 4% alloys became firmly established. At that time, aluminum was three to four times the price •of zinc on a weight •basis. Recent prices, roughly equivalent per lb., make aluminum considerably cheaper than zinc on a volume basis and suggest that increased aluminum content would result in a decrease in the cost per piece due to the lower density of the alloy.Little information could be found in the literature and, therefore, it was decided to determine some physical properties of the higher aluminum zinc-base alloys made from high-purity zinc."

Jan 1, 1953

By Joseph J. Wallace

1. The investigation shows that there are 2 coal beds of major importance in Letcher County from the standpoint of present production - Upper Elkhorn No, 3 and Fire Clay - and 5 beds of minor importance - Whitesburg, Flag, Haddix, Elkhorn Leader, and Amburgy, The Upper Elkhorn No. 3 and Fire Clay beds contain the largest remaining known reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and on 1,600 tons per acre-foot of coal in place, are estimated at 1,353 million short tons as of January 1, 1952. Of this total, 1,056 million short tons ere in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bad characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1953

In this paper is given a general description of the Black Star copper orebody, its relation to the lead orebodies and the controlling factors in the mineralisation.Copper ore, in the form of chalcopyrite, was first noted at Mount Isa in 1930 during the surface drilling campaign to prove the downward continuation of the silver-Iead-zinc orebodies.Details of the occurrence are set out in table 1.Other sub-commercial widths were also disclosed and examination of these occurrences showed that commercial mineralisation could not be expected within 800 ft. of the surface. It was therefore decided that further exploration was not warranted until underground workings had advanced to this horizon.Detailed surface mapping showed two small outcrops of the host rock of the copper orebody. One occurrence, 50 ft. x 75 ft., was of quartz, with leaching suggesting former dolomite. Another outcrop, further north and west of silicified shale, with low grade oxidised copper, has recently been found. Both occurrences were above the hangingwall of the main copper orebody.When the workings in the silver-Iead-zinc orebody reached No. 7 level (875 ft. below the surface) further...

Jan 1, 1953

By Cyril Stanley Smith

METALLURGISTS - or at least metals - have been of central importance in most of the inventions that have shaped the course of man&apos;s history. From the first Bronze Age tools to the iron armor of the Roman soldier, the cannon, cast type for printing, the steam engine, the electric motor and modern electronic devices, technological progress has revolved around some particular property or comb nation of properties selected from the metallurgist&apos;s repertory. The recent utilization of the energy of the atomic nucleus (currently for military purposes alone but with great constructive implications for the future) is no exception to this, although the use of uranium and plutonium in metallic form is of secondary importance, since the significant properties are those of the nucleus and not of the electrons responsible for metallic behavior. THE METALLURGIST AND ATOMIC ENERGY The metallurgist has a role of central importance to play in the future development of atomic energy. Not only must he make and shape the fissionable materials themselves, but he must also develop auxiliary materials to withstand the extreme conditions imposed on nuclear reactor components by the high heat-transfer rates needed for efficient utilization of the fuel and by the perplexing but interesting effects of radiation on the structure and properties of materials. It is doubtful if there is currently any other field potentially more rewarding to a young metallurgist. Quite apart from the all important but relatively short-range considerations of national security is the vision of the effect on civiliza-

Jan 1, 1953