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By J. F. Poland

Location of Basins and Geologic Features of Occurrence: The major ground-water resources of California occur and are stored in the many large alluvium-filled valleys of the state. The deposits of Quaternary age which hold the ground water commonly are called valley fill. Meinzerl has discussed the characteristic features of this fill and showed that for western United States its distribution is concentrated chiefly in western Utah, Nevada, central Oregon, California, southern Arizona, and central New Mexico (see fig. 1). For California the principal ground-water basins are shown on fig. 2. Except for the Mojave Desert and the "Basin and Range" Valleys (fig. 2, Nos. 23 and 23A), which are not shown individually, the basins outlined on fig. 2 contain all the large reservoirs in valley fill within the state. The Sacramento and San Joaquin Valleys (fig. 2) together comprise the Great Central Valley of California, which has an area of about 18,000 square miles. The Sacramento Valley contains about 5000 square miles of valley lands, approxi- mately equal to the area of Connecticut; the San Joaquin Valley embraces about 13,000 square miles, equivalent to the areas of Massachusetts and Connecticut combined. Both the area and the ground-water use in the Central Valley is far greater than for all the other shaded alluvial basins of fig. 2 added together. Except for the Sacramento Valley, all the major ground-water basins of the state are south of Sacramento. The valley fill in these ground-water basins has been transported by streams and most of it has been laid down in alluvial fans, producing the typical alluvial-fan structure of aquifers radiating as tongues from a prismatic pile of coarse, permeable debris at the canyon mouths; these aquifers are encased down slope by poorly sorted materials consisting of a clayey matrix with imbedded pebbles and boulders, interbedded with flood-plain silt. In the deeper inland structural valleys, the alluvial deposits interfinger at depth in the valley bottoms with horizontally bedded lacustrine sand, silt, and clay. The San Joaquin Valley is a good example. In the coastal valleys exposed to the sea, such as the Los Angeles coastal plain, the alluvial fans pass coastward into lagoonal and thence to shallow marine deposits. In all these basins, the gravel is coarsest and most permeable near the apexes of the fans, but tongues or lenses of clean gravel and sand may extend for many miles down the fan. Thus, these water-bearing structures are in a position to absorb stream flow near the canyon mouths and to transmit it through the buried radiating conduits.

Jan 1, 1951

By George H. West, Ross Cummings, L. V. Steck, B. P. Little, Robert D. Pike

The drilling of constantly deeper oil wells has made it imperative that the manufacturer of casing be ever searching for new methods and new materials to meet the increased demands. One phase of this search constitutes the subject matter of the present paper. Starting from the original Drake well in 1859, the depth of wells has advanced by leaps and bounds, until today depths of 6000 to 8000 ft. are common. Conditions point to the necessity for drilling to greater depths, and it is not at all improbable that much of the future oil produc- tion will be from wells around 10,000 ft. deep. The trend to deeper wells is nicely illustrated by the curve in Fig. 1.l The points plotted are the maximum depths attained in the various pools which were at their peak for the years given. It may be of some interest to observe the change that has taken place in the tensile and collapsing stresses over the last 25 years. The pressure at the bottom of a 900-ft. hole, equivalent to the pressure caused by an equal column of water, is only 450 1b. per sq. in. The equivalent water pressure corresponding to the depth of the deepest hole today would be 4762 1b. per sq, inch.

Jan 1, 1930

By William Barrett

IN order properly to evaluate the data related to geomagnetic surveys, it is highly desirable to have all the available information concerning the magnetic properties of the, involved media. This is true of surface as well as subsurface formations and becomes of increasing importance as advancement in instrumental and interpretative technique permits the analysis of relatively slight magnetic reflections of buried masses. Since the magnitude and areal distribution of the usually complex resultant magnetic field at the surface of the earth is a function of the susceptibility1 of the involved matter, it necessarily follows that susceptibility determinations will afford valuable data for geophysical correlation. The present method was developed to meet the need for routine analysis of specimens in the geomagnetic laboratory where it was felt that general utility, ruggedness, ease of manipulation and reproducibility of results was of greater importance than extreme sensitivity.

Jan 1, 1931

By Thomas N. Walthier

ROSPECTING for uranium in the East is hampered by the lack of bedrock exposure due to extensive overburden and residual soil. But, despite the problems of this physiographic province, it has not been ignored in the search for radioactive materials. Since 1951 both the U.S. Geological Survey and the Atomic Energy Commission have had field parties in the eastern U.S. Tempo of private prospecting is increasing, and many discoveries have resulted. AEC work so far has been concentrated in the areas of most numerous discoveries-Pennsylvania, New Jersey, and New York. Accounts of uranium mineralization in the eastern U.S. are found in the old literature and one site in the Mauch Chunk area of Pennsylvania has been known since 1874. In 1949 McKeown examined the original occurrence there and found another southeast of the town. The deposit appeared to have commercial possibilities and a short period of production began in July 1954

Jun 1, 1955

By J. L. Tokich, A. R. Troiano

INTRODUCTION SINCE 1921, when Hull' discovered that cobalt can exist in the face-centered cubic and hexagonal close-packed modifications, the transitions that occur in cobalt have been extensively studied. It is generally agreed that on heating the hexagonal lattice changes to the cubic structure at temperatures ranging from 400 to 500°C although considerable doubt exists as to the exact temperature. Data concerning the temperature of the transformation on cooling are much less concordant and their interpretation has not been satisfactory. The study is further complicated by the fact that many investigators have reported the existence of a high temperature allotropic change in the range 850 to 1020°C, at which the cubic lattice reverts to the hexagonal modification. The transition on cooling, which has been reported as occurring at various temperatures from approximately 400 to 100°C, is of particular interest. Troiano and Greninger2 have recently suggested and considered the possibility of allotropic transformations occurring in pure metals by a shear-type, diffusionless (martensite) transformation. The case of cobalt was specifically discussed and certain observations of previous investigators evaluated in terms of this type of transformation. Table 1 briefly outlines the methods and results of previous investigators of the transformation temperatures of cobalt. MATERIALS AND METHODS The major portion of this investigation was performed with cobalt sheet containing a total of 0.2 pct impurities with carbon present to the extent of 0.1 pct. After melting in an induction furnace under an atmosphere of hydrogen, the carbon content analyzed 0.03 pct. Some observations were repeated with hydrogen reduced cobalt compresses analyzing 99.9 pct pure. No significant variations in results were observed employing the as-received sheet, the remelted stock, or the cobalt compresses. Filings for X ray diffraction analysis were sealed in evacuated glass ampoules. Pyrex glass tubing was used for temperatures below 600°C and for higher temperatures clear fused quartz was satisfactory. After appropriate heat treatment at various temperatures, the specimen ampoules were furnace cooled, air cooled or quenched by crushing under distilled water. This allowed a range of cooling velocities from less than one degree C per sec to greater than 1,000°C per sec. X ray diffraction patterns were taken with a Debye camera and filtered characteristic cobalt K-alpha radiation. The proportion of the existing phases was roughly approximated by visual examina-

Jan 1, 1948

By R. G. Hite, R. G. Rowe

The Crandon deposit, located in northern Wisconsin, is a 65.8 million ton Precambrian volcanogenic massive sulfide deposit which averages 1.4% copper and 5.8% zinc. The deposit is classic in origin, mineralogy and shape. Comprehensive understanding of the geology of both the deposit and the project site has been fundamental to the credibility and success of project feasibility studies and regulatory permit preparation. Mine development in the current investment and regulatory climate requires thorough and timely application of geologic tools. From 1977-1980 geologic activities were focused on the typical objectives of orebody delineation, reserve estimation, depositional geology, and general site investigation. Results from these programs formed the basis for the project's preliminary feasibility studies. Since 1981 further geologic investigations have provided criteria for project design, site management, and operational permitting. Activities have included mine entry position definition drilling, developing geostatistical reserve modeling, large diameter (150 mm) core drilling for mill pilot samples, rock mechanics testing, and evaluation of the glacial overburden/deposit geohydrology for computer simulation.

Jan 1, 1984

By Michael Perch, Charles C. Russell

Nearly 75 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank' standardized by the American Society for Testing Materials. Although this method of classification has been an American stand¬ard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1944

By Sweetser, Ralph A

AT the fall meeting of the Iron and Steel Division, Oct. 4, 1934, in New York, a symposium was held on Slag Control in the Making of Iron and Steel. The chairman was J. H. Nead and the vice chairman, G. B. Waterhouse. The latter presided at both morning and afternoon sessions. The papers and discussions were presented in the order in which they appear on the following pages. To meet space requirements, much of this material has been considerably condensed. CONTENTS Slag Control and the Blast Furnace. By Ralph H. Sweetser. (With dis¬ cussion.) I Slag Control in Rimming Steel. By L. F. Reinartz 5 Slag Control Applied to Low-carbon Steel. By Frank G. Norris 9 Discussion on both papers 11 Slag Control for Basic Open-hearth High-carbon Steel. By W. J. Reagan. (With discussion.) 14 Slag Control for Recarburized Rail Steel. By A. P. Miller and T. S. Washburn. (With discussion.) 18 Slag Control for Alloy Forging Steel. By A. L. Feild. (With discussion.). . . 24 Slag Control for Alloy Forging Steel. By R. C. Good 27 Slag Control in Acid Open-hearth Steel. By Francis B. Foley. (With dis¬cussion.) 29 Slag Control for Basic Electric-furnace Steel. By H. F. Walther. (With discussion.) 31 Physical Testing of Slag. By A. B. Kinzel. . 40 General Discussion 41

Jan 1, 1935

By Dermot M. Ross-Brown

Introduction Slope angles are one of the major factors affecting the shape of the final pit and the location of the walls Due to differences in geology, the optimum slope angles vary from pit to pit and within different parts of the same pit. Indeed, it is not unusual to have different slope angles for the top and bottom portions of the same cross section. The optimization of these slope angles is a major study in itself and this chapter is intended as a general introduction to the subject. It is not intended to be a comprehensive text for the absolute beginner The objective is to put the various aspects of slope stability analysis into relative perspective by describing the vari¬ous analytical techniques available and indicating when each may be most appropriately used References are made to the many excellent texts and papers on slope stability for the reader who does not have a formal training in soil or rock mechanics. In writing this chapter, an assumption has been made that a tentative mining plan has been drawn up, includ¬ing a preliminary estimate of the slope angles. It has also been assumed that all the necessary field and laboratory data has been collected and reduced to a form suitable for input into the stability analyses.

Jan 1, 1979

By H. I. Aaronson, H. A. Domian, G. M. Pound

Zener's two-parameter theory of the y a reaction in Fe-X alloys is extended to encornpass austenite-stabilizing as well as fewite-stabilizing elements, and is then cottzbitzed with statistical thermodynamic theories of Fe-C alloys to permit development of a ther-modynamic description of the proeutectoid fewite reaction in Fe-C-X alloys. Equilibrium tielines are calculated for tile a + y rep'on from experimental data and frort extrapolations of the y/y +a equilibrium surface. Sectzovs of the y/y + 0 surface are calculaled for the tzetastable sstuation LYL u-kich alloyrtg eleitzents do not partition betzseen azrstenite andfer-rite. The finding that the metastable y/a + y curves Lie close to their equilibriuwz counterparts when X = Si, .Vo, Co, Al, and Cu but well below them when X = A/ln or Ari pr-elides a thermodunamic explanation for the expcri1?7e?ztally obserted absence of partition during the proeutec toid ferrite reartlon in the fortner alloys and for the occurrence of partition at hzgher ternperatures in the latter alloys. Cotarison ofno- patitzoa free-energy changes and y/y i a curr,es in Fe-C-X alloys with the equilibrium 11al1es of these quantities in Fe-C alloys furnishes additional qualitative insight into the irqluence of allojling elements upon the kinetics of the proeutectoicl ferrite reaction. THE introduction of a substitutional alloying element, X, appreciably complicates calculation of the thermodynamics of the formation of proeutectoid ferrite from austenite. As noted in the preceding paper,' the positional entropy of the interstitial species is the principal component of the free energy of an interstitial solid solution with which theory has so far been able to deal. One would expect, however, that other components of the free energy of this type of solid solution may be significantly altered by the addition of a substitutional alloying element. Even if the assumptions are made, by analogy to the case of Fe-C alloys,' that changes in the positional entropy of carbon represent a significant part of the thermodynamic effects of an alloying element, and that the remaining effects can be taken into account by fitting the equations developed on this basis to experimental data on Fe-C-X phase diagrams or on the activities of carbon in alloyed austenite and ferrite, the experimental information available on either of these quantities is not yet sufficiently accurate or extensive, respectively, to make such an approach useful. An attempt made by Zener on the former basis to explain the effects of alloying elements on the thermodynamics of Fe-C alloys in terms of a temperature-independent "free-energy change" (actually enthalpy hane') required to transfer 1 mole of an alloying element from austenite to ferrite, in which the "free-energy change" was determined by fitting the theoretical relationships developed to Fe-C-X phase diagrams, thus proved inadequate in part because of deficiencies in the available ternary-phase-diagram data.= Other difficulties of a more fundamental nature, however, also indicated the desirability of a different approach to the problem.3y4y6 zener6 subsequently proposed that the free-energy change associated with y — a transformation in pure iron can be decomposed into magnetic and nonmagnetic components. Alloying elements were assumed to affect those components separately. One parameter was used to describe the quantitative effect exerted on each component. These parameters were evaluated from Ms (martensite-start) temperature data and from other experimental information usually either readily available or measurable with acceptable accuracy. Zener applied this treatment only to the calculation of Fe-X phase diagrams in which X is a ferrite-stabilizing element. In the present study, this treatment is extended to include austenite-stabilizing elements, and then combined with treatments previously considered for Fe-C alloys1 to permit calculation of the thermodynamic quantities of interest in the austenite - proeutectoid ferrite transformation in Fe-C-X alloys, where a number of representative, and commonly used alloying elements are chosen for X, including Si, Mn, Co, Mo, Al, Cr, and Cu. The results are used to explain important features of the partition of alloying elements between austenite and proeutectoid ferrite, as reported in a companion paper7 on the basis of electron-probe analysis, and to provide some additional understanding of the influence of alloying elements upon the kinetics of nucleation and growth of proeutectoid ferrite. Portions of this treatment6 have been clarified in the course of a review by Kaufman and Cohen.3 The consolidated summary of these developments with which this section is begun provides a basis for further clarification of the treatment, from which extension to include austenite- as well as ferrite-stabilizing elements is a natural consequence. The division of the free-energy change associated with the 7 - a transformation in pure iron, into two independent components is formally stated as:

Jan 1, 1967

By W. M. Peirce, R. K. Waring

Zinc of high purity offers definite advantages in certain fields. A process by which zinc of 99.99 + per cent purity is produced by pyro-metallurgical methods is described in this paper. The process consists of a fractional distillation following the primary reduction; this fractional distillation employs the principles of rectification for the separation of lead and other high-boiling impurities and cadmium and other low-boiling impurities. Theoretical Considerations Involved in Production of High-purity Zinc by Distillation Fractional distillation, fractional condensation, and rectification are recognized methods of separating mixtures of liquids. In the field of organic liquids these methods are widely used but not commonly to effect as complete a separation of liquids as is done in the problem under consideration. Zinc boils at 905" C., cadmium at 778" C. and lead at about 1620" C. Zinc may contain from several hundredths of one per cent to over one per cent each of cadmium and lead, and the problem is to reduce these impurities to a few thousandths of one per cent. For lead and zinc, the spread in boiling points is substantial, 715° C., while for zinc and cadmium it is only 127" C. The basic limitation of any separation by distillation may be found from the relation between the equilibrium composition of the vapor and the liquid for all mixtures of the two substances involved. If a mixture of constant boiling point is found, or if a stable compound that vaporizes without dissociation occurs, there is a definite theoretical limit to the degree of separation that is possible when operating at atmospheric pressure with respect to that mixture. Otherwise, any degree of separation is theoretically possible. The equilibrium composition of vapor in contact with liquid mixtures of zinc and cadmiurn at the boiling point has been determined experi-

Jan 1, 1937

By Hans Lundberg

By electrical prospecting, orebodies that do not otherwise manifest themselves at the surface may be located. Conditions favorable to success with the methods are: Favorable geological conditions, such a proportion of minerals of good electrical conductivity in the orebody as will render the latter materially a better conductor than the enclosing rock, situation of the orebody within the range of influence of the electrical currents used and in proportion to this range a sufficient area of horizontal cross section of the orebody. The result is to permit of spotting drill holes accurately and to save the expense of drilling barren ground. THE art of prospecting, like other branches of mining, has developed rapidly during the last ten years, mainly because of the advancement of mining geology, but also because of the development of "geophysical methods," which are based on the different physical characters of minerals and rocks, e. g., specific gravity, elasticity, and magnetic and electric properties. These methods have proved of great value, especially in countries where the rock is covered by soil and direct geologic investigation is out of the question. In prospecting for orebodies, the methods based on studying differences in electrical conductivity have proved most successful; for which reason, the methods of electrical prospecting have been subject to the most energetic and systematic work, especially in Sweden. This paper gives a brief description of the methods of electrical prospecting now in use, especially the new electromagnetic methods, which have not been described before. The great differences in the electrical properties, especially in conductivity, between ore minerals and rock minerals are fundamental to all methods of electrical prospecting, for which reason, the electrical conductivity of ore minerals and rock minerals has been carefully studied in connection with and previous to the development of the various methods of prospecting with electricity. Ore minerals with a metallic luster, such as chalcopyrite, iron pyrite, galena, specular iron, magnetite, etc., also graphite and a number of cows, have considerably higher conductivity than the surrounding rock and soil (see Table 1). The figures of the table denote the specific resistance W, expressed in ohms for a cube with an edge of 1 centimeter.

Jan 7, 1925

SLAG composition, slag constitution, reactions in slag, and reactions between slag and metal-in other words, the physical chemistry of slags-are matters of great importance to the open-hearth operator, whether or not he makes use of any detailed knowledge of them. Although this is a relatively young branch of the science of steel- making, much progress has been made; however, much remains to be learned, and many of the statements that can be made at present are probably--or even certainly-subject to future change. Nevertheless, the physical chemistry of slags is sufficiently developed to provide a reasonably secure basis for real understanding of steelmaking reactions. FUNDAMENTALS OF SLAG CONTROL By way of introduction, some time is spent in this chapter on effecting an easy transition from some of the more "practical" manifestations of slag to discussions couched in the more formal language of physical chemistry. This necessitates a certain amount of repetition, but it is felt that the purpose of the chapter is best served in this way. Reactions in the metal phase have products that find their way into the slag and are important components thereof; they are discussed in detail in the preceding chapter. Some substances distribute themselves Between slag and metal in definite fashion, and others are found only in the slag. Their reactions are a large reason for this chapter. Limitations of Slag Control. The open-hearth process is essentially oxidizing and cannot be otherwise operated. (Oxygen gradients in the furnace, the mechanism of oxygen inflow, and similar subjects are discussed in Chapter XIX.) As shown in the calculations of material and heat balances for the charge (see Chapter XV), from 25 to 50 lb. of oxygen will flow from air or combustion gases into the charge or molten bath during the heat for each ton of liquid steel

Jan 1, 1944

By T&apos Kê, ing-sui

INTRODUCTION ACCORDING to the classical theory of elasticity, the elastic portion of the stress-strain curve is represented by a straight line. Such a representation implies that there is a linear relationship between strain and stress and also that strain is a single-valued function of stress and vice versa. Actually, such a one-to-one correspondence between strain and stress does not exist in real metals. A well-known example is the elastic after-effect on unloading. Another familiar example is damping or internal friction, that is, the dissipation of energy attending vibration. In an extensive review of such phenomena, Zener1,2 has proposed the term "anelasticity" to denote that property of a solid in virtue of which strain is not a unique function of stress in the non-plastic region. The phenomena arising from anelasticity are called anelastic effects. The measurements on inelastic effects are, important in many fields of metals technology. Thus, in precise instruments such as watch springs, difficulties often arise from the slight dimensional changes after fabrication. The internal friction or damping capacity of metals is often an important factor in deciding whether they are appropriate for instruments in which there are accompanying vibrations.' However, for metal scientists, the study of anelastic effects furnishes a powerful tool for understanding many properties of metals in terms of their microstructures or atomic interactions. In order to utilize the anelastic measurements to their fullest extent for acquiring such information, the experimental studies of anelasticity must be interpreted by appropriate mathematical analysis. For a great many problems, however, the necessary information often can be obtained by general qualitative arguments. From the definition of anelasticity, any physical changes occurring in a specimen as a result of the applied stress will cause anelastic effects if such physical changes are accompanied by a delayed change of elastic strain. Under these circumstances, we have the condition that strain lags behind the stress. We may mention the stress-induced transportation phenomena as examples. These include the stress-induced thermal diffusion," the stress-induced diffusion of particles,8-12. and the stress-induced viscous slip along the microelements in metals.12-15 The differential equations describing the microscopic mechanism in these phenomena lead to relations in which stress is linear with respect to strain (and/or their derivatives). Thus if we can - demonstrate that the superposition principle is valid under the circumstances in which the anelastic effects are observed, we would expect in. the macroscopic relation a linear relationship between stress and strain and their derivatives. This report is to describe a number of anelastic effects observed in alpha-iron, and an attempt is made to derive valuable information from a critical study of these

Jan 1, 1948

By Charles C. Russell, Glenn C. South

A primary factor in the selection of coals for making coke at high temperatures is the amount of pressure the coal will exert upon the oven walls when carbonized in modem by-product ovens.l-3 This factor has become increasingly important in recent years because of demands for increased throughput and higher coke yields. As a result of the increasing necessity for assessing coals in regard to their carbonization pressures, more and more research work is being directed toward developing labora-tory-scale tests for predicting carbonization pressures and for showing how blends of coking coals may be modified to eliminate pressures liable to damage coke-oven walls. The specific reasons have never been defined as to why some blends of coking coals develop dangerous carbonization pressures and others do not, therefore specific procedures to eliminate dangerous pressures could not be prescribed. It is true that the major processes occurring during carbonization have been described by many writers,4 and there is a general agreement on the ideas of the changes that occur as coal is transformed into coke. However, there is little evidence relating the processes occurring during carbonization to the pressure developed and the available evidence is very incomplete and often contradictory. This deficiency arises in part from the fact that the fundamental causes of pressure development have not been defined, at least from experimental data, and in turn this is the result of the lack of satisfactory testing equipment for studying the problem. Operating experience has shown several ways of reducing or eliminating dangerous pressures,5 but probably none of these ways is applicable to all blends of coking coals, and such empirical methods often lead to production of inferior coke. They are trial-and-error methods, not designed to remedy specific causes of pressure development. The number of laboratory-scale testing devices designed to estimate the carbonization pressures that result when coals are carbonized in commercial ovens is probably well over a hundred.6 Few of these instruments have remained in use for any length of time, either because the predictions were not sufficiently accurate or, more often, because too many exceptions were found. Often testing devices are operated without any attempt at duplication of conditions in commercial ovens and erroneous and contradictory results are frequently obtained. Therefore, it has seemed desirable to study the properties of coal itself and to determine any relationships between the properties of the coal and the carbonization pressures developed. Relationship between Properties of Coal and Carbonization Pressure Attempts to determine relationships between various properties of coal and carbonization pressures, for the most parti have been indirect because no satisfactory and reliable laboratory testing device has

Jan 1, 1944

By Glenn C. South, Charles C. Russell

A primary factor in the selection of coals for making coke at high temperatures is the amount of pressure the coal will exert upon the oven walls when carbonized in modem by-product ovens.l-3 This factor has become increasingly important in recent years because of demands for increased throughput and higher coke yields. As a result of the increasing necessity for assessing coals in regard to their carbonization pressures, more and more research work is being directed toward developing labora-tory-scale tests for predicting carbonization pressures and for showing how blends of coking coals may be modified to eliminate pressures liable to damage coke-oven walls. The specific reasons have never been defined as to why some blends of coking coals develop dangerous carbonization pressures and others do not, therefore specific procedures to eliminate dangerous pressures could not be prescribed. It is true that the major processes occurring during carbonization have been described by many writers,4 and there is a general agreement on the ideas of the changes that occur as coal is transformed into coke. However, there is little evidence relating the processes occurring during carbonization to the pressure developed and the available evidence is very incomplete and often contradictory. This deficiency arises in part from the fact that the fundamental causes of pressure development have not been defined, at least from experimental data, and in turn this is the result of the lack of satisfactory testing equipment for studying the problem. Operating experience has shown several ways of reducing or eliminating dangerous pressures,5 but probably none of these ways is applicable to all blends of coking coals, and such empirical methods often lead to production of inferior coke. They are trial-and-error methods, not designed to remedy specific causes of pressure development. The number of laboratory-scale testing devices designed to estimate the carbonization pressures that result when coals are carbonized in commercial ovens is probably well over a hundred.6 Few of these instruments have remained in use for any length of time, either because the predictions were not sufficiently accurate or, more often, because too many exceptions were found. Often testing devices are operated without any attempt at duplication of conditions in commercial ovens and erroneous and contradictory results are frequently obtained. Therefore, it has seemed desirable to study the properties of coal itself and to determine any relationships between the properties of the coal and the carbonization pressures developed. Relationship between Properties of Coal and Carbonization Pressure Attempts to determine relationships between various properties of coal and carbonization pressures, for the most parti have been indirect because no satisfactory and reliable laboratory testing device has

Jan 1, 1944

By G. R. M. Del Giudice, A. M. Sadler, Arthur F. Taggart, M. Hassialis

FLOTATION of sulphide minerals and native metals is no longer a practical difficulty. The underlying scientific principles of the method, although not explored in anything like complete detail, have been formulated with sufficient breadth so that the direction of attack on any specific case is clearly indicated. It has been known since the earliest days of flotation that certain of the nonsulphide nonmetal minerals-e.g., sulphur and graphite-would respond to flotation by oils as sulphides do; therefore they have been grouped with sulphides in many patents. But since the development of the chemical theory of collection, 1,2,3 this similarity in action has been one of the facts cited in disproof of the theory by opponents of the hypothesis. 4 5-1 Air levitationt of certain oxidized minerals, both metalliferoust and nonmetalliferous, and separation thereby from other oxidized minerals, is a recent development in practice, although the discovery of the method dates back 17 years .7 This paper presents evidence that the principles underlying the air levitation of the nonsulphide nonmetal minerals are the same as those utilized in the flotation of the sulphides and native metals. It will be apparent immediately to anyone with knowledge of mineral concentration that separation of air-levitated minerals in water from minerals not so levitated is a simple matter of water-gravity concentration, the separating device employed depending solely upon the size of the particles treated and the buoyancy differences effected by the levitation. The usual separating means employed are: (1) a flotation machine for fine, slimy and for well aerated granular material; (2) shaking tables for granular less aerated material. By using large quantities of oil, it is possible to form substantially air-free oil-bound masses or granules of nonsiliceous minerals and to

Jan 1, 1937

By W. R. Hibbard

The increased strength of a polycrystal-line metallic aggregate compared with that of its individual crystals generally has been associated with complex stress distributions at the grain boundaries resulting from atomic irregularity between grains. This disregistry, together with the necessity for adjacent crystals to deform compatibly regardless of the single crystal crystallo-graphic strain mechanism, complicates this mechanism so as to increase the metal's resistance to deformation. Although Taylor1 has shown from purely mechanical considerations the requirement for at least five active slip systems to absorb the complexities during the homogeneous deformation of polycrystalline face-centered cubic metals, experimental studies by Barrett and Levenson2 indicate that this is feasible only in a qualitative sense because of deviations from homogeneous deformation. Seitz and Read in their review3 state: " Unfortunately . . . present knowledge of the grain boundary influence is not sufficient to complement the work in single crystals and provide us with a good foundation for treating polycrystals." The purpose of this investigation was to attempt to clarify the gap between single crystals and crystalline aggregates by an analysis of the effects of dcformational stresses. Some of the results were described by C. H. Mathewson in his 1943 Campbell Memorial Lecture.zl Previous Investigations Since the performance of single crystals deformed under pure stresses has been relatively thoroughly investigated, the most significant researches are concerned primarily with deviations from single crystal behavior of large grained specimens. Qualitative grain boundary effects involving the observed amount of slip werc reported by Carpenter and Elam5 in 1921. Individual crystals in a two or three grained aluminum specimen deformed by tension acted in the normal manner described by Taylor and Elarn4 except for marked modifications at the grain boundaries. There the power to withstand deformation was considerably increased, leaving a ridge on the specimen where decreased slip occurred, often noticeable yi in. from the boundary. Adcock,6 Yamaguchi,' Seumel, Hirstg and others have also reported this phenomenon as a qualitative trend. Yet attempts by O'Neill'o and Ljunggrenll to measure a difference in hardness at grain boundaries in undeformed specimens were unsuccessful. Miller12 measured quantitatively the reduction in slip near the boundary between the single crystal and polycrystalline areas of zinc specimens. These effects consisted of two parts: I. Next to the polycrystalline interface thc distribution of stresses was so altered

Jan 1, 1949

By A. F. Giamei, E. J. Freise

A discussion of the various factors affecting the accuracy of volume fraction determination by the direct comparison X-ray diffraction method is presented. To minimize errors introduced by nonrandomization effects such as preferred orientation and large grain size, as well as errors introduced by statistical effects, an iterative mathematical analysis is introduced. This analysis is applied to all observable diffractio~ spectra from a given specimen by means of computer techniques and is statistically superior to the standard direct comparison technique which utilizes only one or tm sets of intensity spectra. The computer program also presents a graphical interpretation of- the results which enables the investigator to visualize and readily assess the scatter in volume fraction estimates caused by deviations from randomness. Finally, the iterative analysis is applied to experimental data collected from a series of plain carbon steels in both the as-received and spheroidized conditions to determine the volume fraction of cemen-tite present in each case. The results show markedly good agreement with chemical analyses for all spheroidized specimens. In theory, quantitative X-ray diffraction is a power-ful analytical technique for precise determination of the volume fractions of various phases present in a multiphase poly crystalline aggregate. There are two generally used methods; both utilize the fact that the intensity of a diffraction line of a particular phase is a function of volume fraction of that phase present in the aggregate. The more common method is the so-called internal standard technique where a known amount of standard substance is mixed with the aggregate containing the unknown. The resulting ratio of the intensity of a particular diffraction line of the unknown to the intensity of a diffraction line from the standard is used to find the weight fraction of unknown material by reference to the intensity data obtained from a previously prepared set of standards containing the same amount of standard material. The details of this technique are outlined in standard works on X-ray diffraction.' The disadvantages of the technique are that it requires the use of powder specimens and that the powder mixture must be homogeneous near the surface to the maximum effective beam depth. The alternative technique is the direct comparison method in which the ratio of the intensity of a diffraction line of a phase in the aggregate to the intensity of a second-phase diffraction line yields the ratio of the volume fractions of each phase present. This method has been applied most extensively to the determination of the percentage of retained austenite in martensitic steels and to determining the amounts of hcp and fcc allotropic modifications in pure cobalt5 and the amounts of hexagonal and rhombohedra1 modifications in graphite.8 This method is applicable to bulk as well as powder aggregates and is the technique which will be considered in the following text. It is the purpose of the present communication to show that by combining the results of X-ray diffrac-tometry with the use of high-speed digital computers the results of the direct comparison quantitative X-ray analysis technique can be optimized by using all of the data available on a diffraction pattern. THEORETICAL DISCUSSION In optimizing any quantitative X-ray diffraction experiment, the problem of accuracy vs time to collect and analyze the experimental data arises. For any method to be practical, it is required that both experimental and analytical procedures are reasonably short. In most of the previous work performed by the direct comparison method, intensity data from only one or two sets of peaks were used to calculate the volume fraction of phases present in the aggregate. Consequently, rather long-time experimental measurements are required to assure that the intensity data are sufficiently accurate to justify the use of one or two sets of data. By using computer techniques to analyze the experimental data it becomes feasible to use all of the available data on a diffraction pattern. By so doing, the time spent in measuring any one diffraction maxima can be appreciably reduced. Although this results in poor counting statistics for any one maxima, the number of data points available for analysis is greatly increased. Based on the above discussion, it will be assumed that a continuous scanning counter-diffractometer technique will be used to collect intensity data from a two-phase mixture. The integrated intensity of the ith diffraction line from the a phase in the aggregate is given by:'" where is the volume fraction of the a phase, The various quantities in Eq. [la] are angular independent while those in [lb] depend on the hkl spectrum of a particular phase. The meaning of the individual quantities in Eqs. [la] and [lb] are given in Appendix 1. It is convenient at this point to outline briefly the factors which will affect the measured intensity of any one hkl spectrum. a) Extinction effects arise from two independent experimental conditions. Primary extinction arises from a high degree of crystal perfection and results in spectra having lower intensity than predicted by Eq. [I]. Any treatment, such as powdering, which reduces

Jan 1, 1968

By K. E. Brown, F. W. Jessen

By utilizing an 8,000-ft experimental field well equipped with 10 gas-lift valves and 10 Maihak pressure recorders, gas-lift tests were conducted with port sizes ranging from 5/16 through I in. The well was equipped to provide accurate means of measuring surface pressures, temperatures, quantity of injection gas and fluid production. The tests were conducted in 2%-in. OD tubing, and the well was making 95 per cent water. A complete evaluation of gas-lift-valve port sizes shows the relationship of per cent recovery, gas-liquid ratios, minimum pressure created at the operating valve and horsepower requirements for each port. The length of time necessary for the fluid in the tubing to reach equilib.rium conditions after each cycle was recorded. Fallback of fluid at depths of 477, 969, 1,685, 2,493 and 4,290 ft was noted. For each port size, pressure loads of 2.50, 300, 350, 400 and 450 psi were lifted with a valve operating at approximately 550 psi at 6,000 ft. Gas-liquid ratios for each load were varied from excess gas to a gas volume per cycle whereby the load failed to reach the surface. Numerous curves are presented in evaluating the accumulated dara. The results show a 1-in. port to be the most efficient under all conditions. The production of intermittent liquid slugs against different-sized surface chokes was evaluated. These tests were conducted from a 7/16-in. ported valve at 4,072 ft. Tests indicate that, when possible, a %-in. in diameter choke or larger should be used at the surface. In the past few years most of the advancement in gas-lift operations has been made in continuous-flow operations. Yet, it is estimated that at least 70 per cent of the wells on gas lift in the United States are of the intermittent type. Since the term "slug flow" is sometimes used in both intermittent- and continuous-flow operations, it would be well to distinguish between the two types of flow. Continuous-flow gas lift is defined as a method whereby the fluids are produced at a continuous rate at the surface. This generally requires a continuous injection of gas through a surface choke; however, various other control devices sometimes are installed to eliminate freezing, to shut-off gas during natural flow periods, etc. The actual flow of fluids in the tubing may be of the slug type (one of many flow patterns known to exist in continuous flow). Intermittent flow is defined as a method of gas lift whereby the liquid is produced in separate piston-type slugs. Perhaps this type of flow could best be thought of as a ballistic-type flow where the liquid leaves bottom as a piston, propelled by a slug of expanding gas. Gas generally is injected through some type of control at the surface at predetermined intervals. However, the valve may have characteristics whereby gas can be injected through a small choke and still result in a ballistic-type flow. The purpose of the experimental work was to evaluate the most efficient port size to be used on the operating valve for the ballistic type of lift and, in addition, to establish the importance of utilizing a surface choke large enough to allow slugs to be produced without detrimental effects. This work is part of a compre- hensive study of both intermittent-and continuous-flow gas lift, representing a joint project conducted by the Ohio Oil Co., the Sun Oil Co., Otis Engineering Corp, and The U. of Texas. The problem of evaluating port sizes has been given little previous attention. Some work undoubtedly has been done which has not been published to date. Some tests were conducted when the wireline, mechanically-opened valve (Nixon) first came on the market. This valve was capable of utilizing full tubing area as its port size. It is known that this was a very efficient valve, but to the authors' knowledge the results of tests have never been published. EXPERIMENTAL EQUIPMENT These tests were conducted on an actual field well, the Ohio-Sun Unit Well No. 2-E, in the North Markham-North Bay City field, Matagorda County, Tex. The well incorporated 23/8-in. OD tubing and produced 95 per cent water. Since the running of equipment was to be quite elaborate and expensive, a well was selected in which both intermittent- and continuous-flow tests could be conducted. This particular well was capable of producing in excess of 1,000 B/D of liquid (95 per cent salt water), yet with a 3/64-in. in diameter bottom-hole choke, production was controlled to 82 B/D. Most of the intermittent tests were conducted at this low rate. Figs. 1 and 2 show all the surface and down-hole equipment. As can be seen, every attempt was made to insure that ample equipment was available for reliable testing procedures. Fig. 1 shows the surface testing equipment. The input gas was controlled first by a regulator, then