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By J. C. M. Li

A dislocation model is constructed for a cylindrical tilt boundary of which the axis of tilt is parallel to the axis of the cylinder. The strain energy per unit area calculated from this model agrees with thut of an infinite vertical wall of edge dislocations. Based on this model, a dislocation mechanism for the shrinking of such a cylindrical boundary is proposed. The power relation between the grain boundary velocity and the driving force is accounted fm by the stress dependence of dislocation velocity. The activation area for grain boundary motion is found to correlate with that .for Creep in aluminum. In the preceding paper' the velocity of a curved grain boundary is found to be a power function of the driving force, [1] where M is the velocity at unit driving force, y is the grain boundary energy, and p is the radius of curvature. This finding adds another nonlinear rate equation to metallurgical phenomena. While a macroscopic theory for the steady state as just presented2 can be used to understand the shape of the moving boundary, such theory usually does not provide any information about the atomistics of the process. It is attempted in this paper to discuss the nonlinear rate equation in terms of a dislocation mechanism. A DISLOCATION MODEL FOR A CYLINDRICAL TILT BOUNDARY Before a dislocation mechanism can be proposed for the motion of a cylindrical tilt boundary, it is necessary to construct a dislocation model for the boundary. For simplicity, a tilt boundary in a simple cubic lattice will be examined. Although this does not represent the situation in aluminum, it is expected that the general features will be similar. The details of the model in the fcc lattice can be constructed when a refinement of the simple model is called for. A cylindrical low angle tilt boundary in a simple cubic lattice is shown in Fig. 1. Two sets of edge dislocations are needed as shown. A schematic representation is shown in Fig. 2(a). In terms of a continuous distribution of dislocations, the density of dislocations n, of Burgers vector b, in the small segment ds of the grain boundary is Similarly the density of dislocations n, of Burgers vector bz in the same segment ds is where is the tilt angle of the grain boundary. Based on this continuous distribution of dislocations in the grain boundary, it can be shown that the interaction between a small segment of the boundary and the rest of it is zero. Furthermore, the stress produced at any point inside or outside the cylinder is also zero. This shows that the model is acceptable in the sense that the boundary has no long-range stresses. Since the model of continuous distribution of dislocations in the grain boundary does not reveal the interactions among individual dislocations, a discrete dislocation model has to be used for such purpose. For simplicity, an equivalent model is shown in Fig. 3. This arises because the total Burgers vector is, from

Jan 1, 1970

By D. H. Gray, G. Bergamini, I. Fatt

A method developed by soil scientists for measuring permeability anisotropy of soils has been adapted for use in studies of sandstone permeability aniso-tmpy. Studies on Berea and Bandera sandstone show that permeability of these materials decreases upon application of simulated overburden pressure. Permeability reduction of Berea and Grubb sandstone cores subjected to simulated overburden pressure is shown to be a function of the ratio of radial to axial stress. INTRODUCTION The effects of mechanical stress on reservoir rock parameters are now generally accepted as being important in reservoir engineering calculations. In several oil fields the unique behavior of the reservoir has been attributed to the influence of overburden pressure or internal fluid pressure on rock permeability or fluid content. l Although the gross effects of overburden pressure on permeability, porosity, waterflood efficiency, electrical resistance and sonic velocity have now been established,3-9 there are some very interesting, and perhaps important, details of rock behavior under stress that have not heretofore been studied. In this paper we will show that permeability anistropy of several sandstones is a function of overburden pressure. We will also show that permeability reduction of cylindrical samples of two sandstones, when subjected to mechanical stress, is a function of the ratio of radial to axial stress. Most studies of overburden pressure effects made in the past have attempted to duplicate reservoir conditions by applying hydrostatic external pressure on all surfaces of the sample. Assuming perfect elasticity, that is, no viscoelastic flow during geological time, reservoir rock in situ cannot be under hydrostatic stress as is apparent from the value of 0.25 for Poisson's ratio for most rock. In the absence of tectonic forces the horizontal stress component If there are directional permeability effects, as has been reported from field and laboratory studies, l0,11 then one would expect hydrostatic stress as used in the laboratory to give a different permeability reduction from that occurring under reservoir stress conditions. The influence of stress on directional permeability was measured by a modification of the method first described by Maasland and Kirkham for use on soil samples.12 Their method permits calculation of the permeabilities along each of the three mutually perpendicular axes of a cubic sample. The modification reported in this paper extends the method to observing these permeabilities when the sample is under hydrostatic stress. The Hassler sleeve type of core holder is satisfactory for studying overburden pressure effects on permeability if a known force is applied to the end plugs. Wyble6 used a sleeve core holder but did not load the end plugs. In this paper we combine sleeve pressure and axial force to give permeability changes which we believe are close to those occurring in reservoirs when reservoir pressure changes. The combination of sleeve pressure and axial force assumes, however, that the sleeve pressure simulates both vertical stress and horizontal stress in one direction. METHOD PERMEABILITY ANISOTROPY The Maasland and Kirkhaml2 method of measuring permeability anisotropy uses a cube of porous material which is Open On three faces and has discs with a Center hole for an air inlet cemented to the other three mutually perpendicular faces (Fig. 1). The rate at which air pressure falls in a bottle of known volume, and pressure slightly above atmospheric, when the bottle discharges through each disc, is

By G. C. Gould

The nature of freckle segregation is determined by chemical analyses, microradiograplzy, and electron microprobe. In addition, the influence of chemistry variation on freckle formation is studied in laboratory experiments. It is demonstrated that controlled laboratory solidification can produce freckle segregation. "FRECKLE" segregation is a discontinuous, rod-like segregation observed in vacuum consumable -electrode ingots. Figs. 1 and 2 show this segregation as pencil-like, dark etching areas of segregation found in longitudinally and transversely sectioned consumable-electrode ingots. In most cases the segregation is perpendicular with respect to gravity and parallel to the longitudinal axis of the ingot. The segregation is most often encountered at or around midradius in large vacuum consumable-electrode ingots. The austenitic alloys, A-286* and 718, † have shown particular susceptibility to this mode of segregation. The origin of these rodlike pockets of segregation is not well-understood. It has been suggested that the segregation is a result of a portion of the electrode dropping off and passing through the arc un-melted. On the other hand, smeltzer1 has demonstrated the freckle segregation in A-286 to be comprised of low-melting constituents relative to the matrix melting point. The discontinuous nature of the segregation is the most perplexing facet of the freckle-segregation problem. It was to gain some insight into this part of the problem that this work was undertaken. I) PROCEDURE At the outset of the work identification of the phases present and the elements concentrated in the freckle areas was undertaken. The electron micro-probe was used to determine general enrichment as well as -specific phase chemistry. Microradiography using cobalt and chromium radiation was also used on the freckle areas again to determine the elements involved in the segregation. X-ray diffraction patterns were made from portions of these same foil specimens. Optical microscopy and Knoop hardness measurements were also used

Jan 1, 1965

By E. Lancaster-Jones

THE gravity magnitudes obtained by means of observations with the Eötvös balance in the field are necessarily resultant or total effects due to all abnormalities of mass distribution, including even the effects due to the ellipticity and rotational motion of the whole earth. Since the object of the survey is to isolate the effects which arise solely from some particular subterranean feature, and to deduce therefrom the configuration and extent of this feature, the first step is to eliminate from the observed effects all those due to "disturbing" (i, e., unwanted) features, whether above or below the surface of the ground. The disturbing features have different characteristics, according to their situation relative to the center of the balance and to the horizontal plane through the foot of the balance, or station point; this diversity was recognized by Eötvös, who divided the total effects into so-called Normal, Terrain, Topographical, Cartographical and Subterranean effects. This classification has been adhered to by most subsequent investigators, but the writer prefers to employ the term "three-dimensional," which really indicates the essential character of the class of effect known as "Subterranean," at any, rate from the standpoint of the computer of effects. Before disturbing effects can be eliminated, the features must be measured up or surveyed, whether by topographical, mining, or boring methods, and then the effects of each feature calculated and subtracted from the total observed effects. After this the problem of interpreting the residual effects will itself necessitate the computation of the assumed feature, or even a series of trial features.

Jan 1, 1928

By Glenn Southward

This describes a highly concentrated mining system consisting of a series of short faces arranged to get complete recovery of coal with the maximum protection for the men and equipment. A series of conveyors collect the coal from eight faces and discharge into mine cars at a central loading point on a main haulageway. The conveyor is sectional and, by a multiple-drive arrangement, the same standard parts are used to construct a unit of any length. THE. V system of mining used at the Norton mine of West Virginia Coal & Coke Co. was designed as a modified longwall with face conveyors, FIG. 1.-GENERAL DESIGN AND ARRANGEMENT OF FACES IN V SYSTEM. for use under roof conditions that would not permit regular longwall methods. This mine is in the Lower Kittanning seam, which averages about 6 ft. in height. There is from 20 to 30 ft. of slate and shale immedi-

Jan 2, 1924

By E. D. Cockrell, E. P. Hayes

The figures herein presented show that during the year 1938 drilling in the Texas Gulf Coast continued at a slightly lower rate than during 1937. In 1938 there were 21 new oil fields added to the Texas Gulf Coast; also numerous extensions and new sands in old fields. This report for 1938 cannot be compared with the report for 1937 in Volume 127 of the Transactions, because the area covered by this report is less than that covered last year. The cross-hatched area on Fig. 1 shows the limits of this report. Of the new fields, Cordele, in Jackson County, Eureka Heights and Fairbanks, in Harris County, Francitas, in Jackson County, LaRosa, in Refugio County, and League City, in Galveston County, have the greatest promise of prolific production. The 1938 production for the Gulf Coast area was 92,530,467 bbl. as compared to 94,019,355 bbl. for the same area in 1937. This shows a decrease of 1,488,888 bbl. during 1938, regardless of the increase due to the 21 new oil fields. This decrease was caused mainly by the Saturday and Sunday shutdowns (68 days during 1938) and by cut in allowables. The 68 shut-down days amount to approximately 18.6 per cent of the 365 days possible for production. The decrease in the 1938 production amounted to approximately 1.58 per cent. Therefore there was actually a potential increase in the year's production. During the past year, 1637 wells were completed as oil wells, 68 as gas wells and approximately 461 dry holes, as compared to 1672 oil wells, 83 gas wells and 448 dry holes in 1937 on the Texas Gulf Coast. Total wells drilled were 2166 in 1938 and 2203 in 1937. Condensate. sands in old fields and new fields are continuing to increase in importance from the standpoint of retrograde condensation and pressure maintenance. The following fields had major extensions during the year 1938 from the standpoint of increased areas of old sands and new deeper sands:

Jan 1, 1939

By E. D. Cockrell, E. P. Hayes

The figures herein presented show that during the year 1938 drilling in the Texas Gulf Coast continued at a slightly lower rate than during 1937. In 1938 there were 21 new oil fields added to the Texas Gulf Coast; also numerous extensions and new sands in old fields. This report for 1938 cannot be compared with the report for 1937 in Volume 127 of the Transactions, because the area covered by this report is less than that covered last year. The cross-hatched area on Fig. 1 shows the limits of this report. Of the new fields, Cordele, in Jackson County, Eureka Heights and Fairbanks, in Harris County, Francitas, in Jackson County, LaRosa, in Refugio County, and League City, in Galveston County, have the greatest promise of prolific production. The 1938 production for the Gulf Coast area was 92,530,467 bbl. as compared to 94,019,355 bbl. for the same area in 1937. This shows a decrease of 1,488,888 bbl. during 1938, regardless of the increase due to the 21 new oil fields. This decrease was caused mainly by the Saturday and Sunday shutdowns (68 days during 1938) and by cut in allowables. The 68 shut-down days amount to approximately 18.6 per cent of the 365 days possible for production. The decrease in the 1938 production amounted to approximately 1.58 per cent. Therefore there was actually a potential increase in the year's production. During the past year, 1637 wells were completed as oil wells, 68 as gas wells and approximately 461 dry holes, as compared to 1672 oil wells, 83 gas wells and 448 dry holes in 1937 on the Texas Gulf Coast. Total wells drilled were 2166 in 1938 and 2203 in 1937. Condensate. sands in old fields and new fields are continuing to increase in importance from the standpoint of retrograde condensation and pressure maintenance. The following fields had major extensions during the year 1938 from the standpoint of increased areas of old sands and new deeper sands:

Jan 1, 1939

By R. H. Card

The geophysicist is interested greatly in the resistivities of different formations or parts of the earth's crust; sometimes he is interested in a single figure in the nature of an average, or what may be called the effective resistivity, of all the formations or parts of the crust at a given location to a certain depth. Conversely, the engineer whose work is concerned with the coordination of power and communication lines in such a manner as to avoid electrical interference between these two types of facilities is concerned very much with this effective resistivity; to a lesser extent he is interested in the resistivities of individual formations. In connection with his work the coordination engineer often estimates the effective resistivity of the earth from measurements of the mutual impedances of lines; in other instances he derives from measurements of a different type the resistivities of different layers of the crust and synthesizes these to obtain an estimate of the effective resistivity. In connection with problems concerning the coordination of power and telephone lines, measurements from which earth resistivities can be estimated have been made at many points in the United States by the American Telephone and Telegraph Co. and its associated companies, in cooperation with various power companies and with railroad companies having electrified sections of line. Other such measurements have been made by the Joint Subcommittee on Development and Research of the Edison Electric Institute and the Bell Telephone System. A study has been made of the correlation of these data with the ages and types of materials of the strata of the earth's crust at each of the test locations. The purpose of this study has been primarily to provide information to assist in predicting the order of magnitude of effective resistivities to be used in the preliminary consideration of problems concerned with the coordination of power and communication lines. To make the results of such a study most useful, it is essential that the geological data to be secured when such a prediction is wanted be readily obtainable. Data on the ages of strata and the types of materials composing geological structures can usually be obtained, therefore particu-

Jan 1, 1940

By R. H. Card

The geophysicist is interested greatly in the resistivities of different formations or parts of the earth's crust; sometimes he is interested in a single figure in the nature of an average, or what may be called the effective resistivity, of all the formations or parts of the crust at a given location to a certain depth. Conversely, the engineer whose work is concerned with the coordination of power and communication lines in such a manner as to avoid electrical interference between these two types of facilities is concerned very much with this effective resistivity; to a lesser extent he is interested in the resistivities of individual formations. In connection with his work the coordination engineer often estimates the effective resistivity of the earth from measurements of the mutual impedances of lines; in other instances he derives from measurements of a different type the resistivities of different layers of the crust and synthesizes these to obtain an estimate of the effective resistivity. In connection with problems concerning the coordination of power and telephone lines, measurements from which earth resistivities can be estimated have been made at many points in the United States by the American Telephone and Telegraph Co. and its associated companies, in cooperation with various power companies and with railroad companies having electrified sections of line. Other such measurements have been made by the Joint Subcommittee on Development and Research of the Edison Electric Institute and the Bell Telephone System. A study has been made of the correlation of these data with the ages and types of materials of the strata of the earth's crust at each of the test locations. The purpose of this study has been primarily to provide information to assist in predicting the order of magnitude of effective resistivities to be used in the preliminary consideration of problems concerned with the coordination of power and communication lines. To make the results of such a study most useful, it is essential that the geological data to be secured when such a prediction is wanted be readily obtainable. Data on the ages of strata and the types of materials composing geological structures can usually be obtained, therefore particu-

Jan 1, 1940

The suggestions of the members of the Institute are very much desired by-the Committee on Nominations prior to deciding upon its nominations to fill the places of those officers who retire early in 1917. The Committee must make its final report to the Board of Directors early ill October. The members are, therefore, -asked to send in promptly their suggestions for Directors as well as for Vice-Presidents and President. The Committee hopes to hear from a large number of the members. The officers to be elected at the annual meeting in February, 1917, are: One officer, known as Director and president. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and VII of the Constitution, and to By-Law XIII, which reads as follows: "The geographical districts to be considered by the Committee on Nominations shall be as follows, until otherwise ordered by the Board. District No. 1. New England, New York, and New Jersey, excepting New York

Jan 9, 1916

By Charles T. Holland

This discussion is concerned with those comparatively infrequent bumps that eject material from the failed mass with enough energy to wreck heavy machinery and seriously injure or kill people. In such cases there is a loud report, and the pressure waves set up in the mine atmosphere wreck ventilation controls several hundred feet from the site of the failure. Vibrations are induced in the earth's crust which may be detected several miles from the point of origin, and explosive gases may be released in large quantities.* Usually a dense suspension of dust is produced from the failed mass, together with dust placed in suspension by the resulting air blast. These rock bursts or bumps have also been called mountain shots, bounces, pillar bursts, and crumps. Such occurrences, when extensive, are serious catastrophes, and may force abandonment of the mine.1

Jan 9, 1958

By R. D. Nelson, J. C. Shyne

The ß and a ß transformations in plutonium were studied with particular emphasis on the transformation kinetics and microstructure. Significant observations are: 1) The kinetic data show conclusively that the ß — a transformation in high-purity plutonium can proceed isothermally with no athermal component. 2) Plastic deformation of the stable (3 phase retards the subsequent (3 — a transformation. 3) Plastic deformation of the stable a phase accelerates the a — ß transformation; the acceleration is attributed only to residual stresses. 4) The a and a?a volume changes occur anisotroPically in textured plutonium. 5) An apparent crystallogvaphic relationship exists between the parent and the product phases of the and (3 — a transformations. 6) Both applied uniaxial compressive stresses and uniaxial tensile stresses raise the starting temperature for the ß — a transformation. 7) A given uniaxial tensile stress favors the a — ß transformation more than an equivalent applied uniaxial compressive stress opposes the transformation. These observations of the (ß —a and a — ß phase changes in plutonium are consistent with known mar-tensitic transformations. ThIS paper elucidates some of the characteristics of the a— ß and ß —a transformations in plutonium. Because considerable conjecture exists about the mechanisms by which the phase transformations occur in plutonium, experiments have been performed to provide indirect information concerning the mechanisms responsible for the a —ß and ß -a transformations. Indirect information is of particular value in the study of plutonium because of the experimental difficulties presented by the metal. Single crystals have not been produced in any of the allotropes. The large density results in high X-ray and electron-absorption factors and consequently complicating X-ray and electron diffraction. The kinetics of ß — a and a — ß transformations of plutonium and the behavior of the transformations under a variety of conditions have been investigated in detail. Information about the mechanisms of the allo-tropic transformations of plutonium was obtained indirectly from three sources: 1) the effect of plastic deformation of the stable parent phase upon the transformation kinetics; 2) the behavior of the metal transforming under applied stresses; and 3) the microstruc-tural and crystallographic features between parent and product phases. PHASE-TRANSFORMATION CHARACTERISTICS In characterizing solid-state phase transformations in metals and alloys, it is useful to define several types of transformations. An aim of the present work was to identify the low-temperature transformations in plutonium by type, i.e., as martensitic or nonmar-tensitic. Practical definitions for these terms follow. The terms commonly used to categorize phase transformations lack universally accepted definitions. This confusion arises doubtlessly because some terms specify crystallographic or morphological character while other words have a kinetic or a thermodynamic connotation. For example, martensitic specifies certain definite crystallographic restrictions. Unfortunately, martensitic is sometimes used in an ill-defined way to imply kinetic characteristics. Further confusion attends the use of such expressions as nucleation and growth, diffusional, and massive. From time to time new systems of phase-transformation nomenclature are suggested; unfortunately none of these has gained general acceptance.1,2 The authors of the present paper have no intention of entering the controversy. We recognize that some readers may object to the nomencliture used here. For exampie, the terms military and civilian have recently been used in much the same way as martensitic and non-martensitic are used in this paper. This paper is intended to describe several specific details of the low-temperature phase transformations in plutonium. The authors have found it useful to identify these transformations as martensitic; the term was chosen as the best available to describe the experimentally observed features of the transformations studied. A martensitic transformation is one that occurs by the cooperative movement of many atoms; the rearrangement of atoms from parent to product crystal structure occurs by the passage of a mobile semico-herent growth interface. The geometric features characteristic of a martensitic transformation are a specific orientation relationship between the product and parent phase lattices, a specific habit-plane orientation for the growth interface, and a shape change with a specifically oriented shear component. There is no alloy partition between the parent and product phases in a martensitic transformation. Martensitic transformations may display either athermal kinetic behavior or thermally activated isothermal kinetic behavior. Some martensitic transformations occur isothermally, although more commonly martensitic transformations are athermal. Isothermal martensitic transformations are suppressible by rapid cooling. In athermal martensitic transformations, nucleation and growth are not thermally activated and the transformations are essentially time-independent. Nucleation, growth, or both can be thermally activated in isothermal martensitic reactions. Transformation of the parent phase into a marten-

Jan 1, 1967

By J. B. Sellers, G. R. Haworth, P. G. Zambas

Rock mechanics research was carried out in the Anvil Points mine, Rifle, Colo., in the period 1964-1968, with the dual purpose of providing oil shale to the retorts of six major oil companies and to perform research on mining cycle operations to maximize extraction under safe conditions. An 80% extraction ratio within the mining area proved feasible. Test results provided data on optimum pillar and roof design. Studies of mine orientation showed that the mining headings should take into account the prevailing joint patterns and also the directions of the principal in-situ stresses acting in the region.

Jan 1, 1973

By N. K. Chen, R. Maddin, R. B. Pond

A METHOD has been described by Andrade' for obtaining very rapid grain growth so that single crystals of high melting point metals could be made with comparative ease. The furnace construction was essentially a very thin wire through which was passed an electrical current so that "a high uniform temperature" was maintained. The wire was surrounded by a fused quartz tube from which the air had been evacuated. Andrade applied this method to the growth of single-crystal wires of alpha iron, and Tsien and Chow2 prepared single crystals of molybdenum 0.25 mm diam in this way. In the present report a method is described in which the basic idea of the Andrade furnace is utilized. However, modifications are employed so that large single crystals of molybdenum or of any refractory metals can be grown. Furnace The modified Andrade furnace is shown in Fig. 1, and the detailed drawing of its construction can be seen in Fig. 2. The furnace proper consists of a 2'/2-in. diam fused silica tube, 20 in. long, which is evacuated continuously at the bottom. Two water-cooled copper electrodes hold the specimen by means of collets held in place in the electrodes by set screws. These electrodes serve also to transmit power to the specimen. The lower electrodes can be clamped to the stand, while the upper electrode is fastened in place to the bellows which in turn is further connected to one side of the lever arm, flexibly supported at the top. After the specimen is mo;nted- and the vacuum is secured, the lever arm is adjusted by means of the counter weight so

Jan 1, 1952

DeLamar, the largest silver mine in the United States outside the Coeur d’Alene District in Idaho, came into production in April 1977. It is a joint venture of Earth Resources Company and Canadian Superior Oil Co., with Earth Resources being the operator. The property is a consolidation of several old operations dating back to the 1800s; the better known of these are the DeLamar and Sommer-camp mines. DeLamar is situated in southwestern Idaho near the Oregon border in the Owyhee Mountains, 88 km (55 miles) southwest of Boise, Idaho. Heavy snowfalls and very low temperatures are common in the wintertime. Planned production was 77,500 kg (2.5, million oz) of silver and 5 13 kg (16,500 oz) of gold per year. Expected life at a milling rate of 1,540 mtpd (1,700 stpd) was 20 years, with an ore grade of 144 g Ag and 1.58 g Au per mt (4.2 oz Ag and 0.046 oz Au per st). Present production is at the rate of 1,900 mtpd (2,100 .stpd). The total cost to bring the mine into production was reported to be approximately $22 million, and the mill was reported to have cost about $10,000 per daily ton of design capacity. At DeLamar, naurnanite (Ag2Se) is the principal silver .mineral occurring with acanthite (Ag2S) disseminated through quartz veins and a silicified rhyolitic ash-flow tuff of Miocene age. The mineralization is relatively iron and manganese free and is readily amenable to cyanidation giving recoveries of 85% silver and 92% gold, which occurs free. When the plant was started, considerable difficulties were encountered in handling the wet sticky ore because of the high clay content. Following primary crushing, the ore is stockpiled. Due to the sticky nature of the ore, the vibrating feeders initially installed under the stockpile were replaced by a reclaim hopper and an apron feeder which was fed 24 hours a day by a front-end loader. The minus 200 mm (8 in.) ore is fed to a 5.5 m by 2.75 m (18 ft by 9 ft) autogenous mill followed by a 2.75 m by 4.57 m (9 ft by 15 ft) ball mill and cyclones. The mills are equipped with 750 kw and 520 kw (1,000 hp and 700 hp) motors. Both mills discharge to the same cyclone feed sump and a portion of the cyclone underflow is returned to the autogenous mill. Cyclone overflow, which is 20% plus 74 microns (200 mesh), is leached in four agitators in series for 72 hours (45 hours at the 2,100

Jan 1, 1981

By Edward Estabrook

THE Salt Creek oil field in Natrona County, Wyo., is the largest pool that has been found in the Rocky Mountain region and one of the largest in the United States. Many features of its production records are of peculiar interest, because of the unusual slowness with which it has been developed. This paper is published by the permission of the Midwest Refining Co., whose records have been freely drawn upon. Many mem¬bers of the Midwest organization have assisted in the collection of the material, but Messrs. F. E. Wood and L. E. Smith have been particularly helpful. The Salt Creek oil field is situated on a great dome with a closure of about 1500 ft., which rises at the northern end of a long anticline extending north-northwest by south-southeast for fully 25 miles. The productive area includes parts of townships 39 and 40 north and ranges 78 and 79 west of the sixth principal meridian. The Teapot oil field occupies a minor dome at about the center of the same anticline and adjoins the Salt Creek oil field on the southeast. The Teapot Naval Reserve includes the Teapot Dome and about 760 acres of the Salt Creek dome. In this paper, the Salt Creek oil field will be considered as' including all of the dome, except that part which lies within the Teapot Naval Reserve and the area west of the dome where oil is produced from shale crevices.

Jan 9, 1925

By E. H. Crabtree

Research on the iron ranges begins to bear fruit in big plant construction -Big coppers raise capacity, build at new Arizona, Michigan, Nevada, properties - Hydrometallurgy comes to fore with new uranium ore treatment and the Chemico process for nonferrous metals -

Jan 2, 1953

By Charles Barrett

THE experiments reported in this paper have been fruitful in disclosing the mechanism of the deformation of iron in compression. They have established the nature of "deformation bands," "etch bands," or "X-bands," that have been a recognized but little understood feature in the structure of cold-worked metals since the early days of metal-lography, and have shown the role of the bands in the development of preferred orientations by cold-working. The work has also shown the relation of the orientation of individual grains to the preferred orientation of the aggregate. Some of the methods previously used in the determination of the indices of slip planes and slip directions are shown to be untrustworthy in the presence of deformation bands. The conclusion is reached that many slip planes and slip directions must operate during each stage in the compression of a single crystal, and that theories failing to take account of this require revision. In conducting the experiments a method f compression has been used by which extreme reductions can easily be reached, even to the limit set by the metal's capacity to deform with-out fracture. The work is a portion of a research program on the plastic properties of iron and steel. It is being used as a foundation for studies of orienta-tions resulting from recrystallization and is being extended to other metals and other types of deformation.

Jan 1, 1938

By E. P. Mathewson

The early development of the reverberatory furnace for smelting copper-ores was the work of the Welsh smelters, particularly those of Swansea. The first record of a reverberatory furnace is made by Jars, who states that in 1755 copper-smelting was effected .in reverberatory furnaces at Middleton-Tyas, in Yorkshire, England. The first patent, of any importance, for improvements in reverberatory furnaces was granted to Thomas Williams in 1778 for the granulation of the regulus. The next was that of William Evetts, in Sheffield, in 1812, for the cooling of the fire-bridge by the admission of air. Charge-hoppers above the furnaces were in common use in 1848. The size of the hearth of the furnaces about the beginning of the 19th century was commonly 11 by 8 feet. No material development was made until the Welsh process mas brought to Colorado, where Richard Pearce, as manager of the Argo works, near Denver, developed the furnace to meet the requirements of a custom plant, under keen competition with lead-silver smelting-plants, using blast-furnaces. His improvements are outlined in Fig. 1, elaborated by permission from E. D. Peters's excellent work,' to which the reader is referred for further details. This figure shows that the furiiaces were in 1878, 9 ft. 8 in. by 15 ft. in hearth; and in 1894, 16 by 35 ft., while the capacity of the furnace had been increased from 12 tons per 24 hr. to 50 tons in the same period.

Jan 1, 1913

By R. P. Carreker, J. G. Leschen, J. H. Hollomon

The external appearance of a crystal which has undergone plastic flow suggests that adjacent blocks of the crystal have glided bodily past one another along the slip planes. However, the great discrepancy between the shear stresses calculated to effect such a movement and those actually observed has for many years stimulated searches for more satisfactory interpretations of the slip process. Appreciable success in these efforts has been realized by assuming the presence in the crystal of various sorts of imperfections and by considering the consequences of the presence of these flaws when stress is externally applied. The theory that has received the most attention recently—that of dislocations—postulates the occurrence of small, mobile imperfections or dislocations which move through the crystal along the slip direction, each dislocation being attended by a local shear displacement of one interatomic distance. Thus only that portion of the crystal through which the dislocation has passed may be said to have slipped. Since each dislocation produces a displacement of only one interatomic distance, an avalanche or train of many dislocations would be necessary to account for the observed displacements of several hundred or thousand interatomic distances. The salient point of the theory of dislocations is the concept that a slip band does not suddenly appear in its entirety. On the contrary, it grows progressively across the slip plane as the individual dislocations successively appear and advance in a train through the crystal. However, the concept of growth is not intrinsic only to the theory of dislocations, since atomistic mechanisms other than that postulated by the dislocation theory can quite probably also describe the growth of a slip band. For instance, a slip band might resemble a disc-like interface that appeared and then grew continuously from a small size, producing a displacement that increased with the size of the disc. Whatever the precise mechanism, the concept of growth is in itself consistent both with the observed low values of critical shear stress and with the experimental observation that slip bands frequently do not traverse the entire crystal. The likelihood that slip bands grow implies that they must first be nucleated and that the initiation of slip can therefore be analyzed in terms of the general concepts of nucleation. Indeed, this suggestion was advanced1 several years ago, but the matter does not appear to have been further pursued. Recent advances in the theory of nucleation 2,3,4 have encouraged such a treatment of the slip process. As will presently be demonstrated, this approach to the problem not only accounts successfully for the incubation periods that have been observed 5,6 to precede slip but also predicts certain transient effects in the deformation process. The existence of these transients apparently has not hitherto

Jan 1, 1949