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By Thomas Watson

Introduction THE occurrence of zircon in pegmatites of acidic composition is recorded by many observers both in this country and abroad, and they form one of the most important geologic modes of occurrence of the mineral.' As is well known, commercially the most important American locality for zircon is near Zirconia in Henderson County, North Carolina, where many tons of the mineral have been obtained from a kaolinized pegmatite dike 100 ft. wide and traced for 1 ½ miles along the direction of strike N. 50° E. Zircon may be developed in pegmatites as inclusions in the principal rock-forming minerals, chiefly quartz and feldspar, and as a separate megascopic constituent in the form of grains and crystals not exceeding, as a rule, 2 in. in size, and usually smaller. In the Henderson County, North Carolina, pegmatite, zircon occurs in prismatic crystals with pyramidal terminations measuring up to 30 mm. in diameter, associated chiefly with the feldspar. In some of the apatite veins of Canada, which are closely allied to pegmatite dikes, zircon is reported in crystals upward of 6 in. in length and 2 in. 'and more in thickness. Zircon in large masses occurs in Virginia in the well-known pegmatites near Amelia in Amelia County, and near Gouldin in Hanover County. Both localities are in the middle eastern portion of the Piedmont Plateau province, and are separated by a distance of about 40 miles in a northeast-southwest direction. The rocks of both areas, including the pegmatite bodies, are in an advanced stage of decay, and, the hard and moderately fresh rocks are concealed beneath a cover of variable thickness of rock decay derived by the normal processes of weathering. Exposures, there-

Jan 7, 1916

By AIME AIME

A PAPER recently presented before the Anthracite Section of the A. I. M. E. by S. J. Phil- lips, Mine Inspector, Fifth Anthracite District, Department of Mines of Pennsylvania, covering the water hazards in the anthracite coal mines of the Lackawanna River Valley, was especially timely because the conditions there are duplicated to a large extent in the Wyoming Valley, which is traversed by the Susquehanna River with its many large tributary streams. Also, in the southern anthracite field, where there are a number of large creeks, similar pumping problems and mine water hazards will in time be presented if mining is continued to its conclusion.

Jan 1, 1936

By E. L. Anders

The Mile Six pool is located on the La Brea-Parinas Cullcession of International Petroleum Co., Ltd., in northwestern Peru on the west coast of South America. The reservoir pressure in this pool has been maintained within 200 psi of its initial value throughout its history, and gravity drainage has played an important role in the production behavior. It has now produced 95 per cent of its estimated ultimate recovery. It is estimated that this interesting oil pool will ultimately produce 67 per cent of the initial oil in place and that the resulting residual oil saturation may be as low as 19 per cent of the pore volume (29 per cent of the hydrocarbon pore volume). An evaluation of reservoir rock and fluid characteristics and ultimate oil recovery is presented. INTRODUCTION This study of Mile Six pool was made to evaluate its performance according to latest available information. The production performance of this pool has been discussed in various articles in the past. and the reported behavior has been used as an example for application of computation procedures for gravity drainage depletion' and as an illustration of field behavior under gravity drainage or expanding gas cap drive. There have been wide variations in reported values of initial oil in place, reservoir oil volume factor. connate-water sauration, volume of effective sand, and ultimate recovery because of the paucity of reliable basic data. These various factors have been determined as accurately as practicable with the latest available information, and this evaluation is presented herein. The production history of Mile Six is an excellent example of gravity drainage depleion with effective pressure maintenance by gar injection. GENERAL Mile Six pool was discovered by cable-tool drilling in November. 1927. when well 1996 was completed in the Parinas sand. After slow development with cable tools and sporadic production. the pool was opened to continuous pro(iuction in November. 1933. and develpment was completed with rotary rigs. Pressure maintenance was started in December, 1933. by returning gas to upstructure wells. Most of the development was 'completed by 1937, but some additional wells were drilled in the period 1939-1947. and several old wells were deepened. A total of 46 oil and gas wells and 4 dry holes were drilled on approximately 7-acre spacing. Of the producers. 21 are now flowing. 2 are pumping. 44 are gas input wells. 3 are abandoned. I is a gas well shut in. and 15 are shut in because of non-commercial production or high gas-oil ratio. The locations of all wells are shown on the map of Fig. I. Total oil production on Dec. 31. 1952, was 30,867,373 bbl: cumulative gas production was 22,023,777 Mcf; and 26,410,946 Mcf of gas had been returned to the reservoir. These figures do not include oil and gas lost ill a blowout in January. 1940. GEOLOGICAL DESCRIPTION Mile Six pool is located on the northern end of a structural spur projecting from the La Brea-Negritos uplift.' The spur is probably a reflection of a basement structure. It plunges gently to the north, i broken into a complex series of fault blocks. and contain.; the Verdun Alto. Section Sixteen. and Mile Six pools. The Parinas handstone (lower Eocene!. which is the producing formation in Mile Six. occurs at an average depth of 2,200 ft in the pool and dips north and east at from 15' to 20". The pool covers an area of approximately 350 acres. Mile Six is downfaulted about 600 ft from Section Sixteen pool to the soutb. and a major fault forms its western boundarv. The north and east boundaries are formed by the intersection of the sand top with the water-oil contact which occurs at approximately 2.440 ft subsea. An original gas-oil contact probably existed at about 1.875 ft subsea. Fig. 1 presents the latest structural interpretation of the pool. and Fig. 2 is an isopach map showing thickness of the total Parinas formation above the original water-oil contact. The heavy lints of Fig. 1 are contours on the sand top, and the fine lines are contours on the fault planes. This type of straight-line structural map was developed 1)) International's geologists to reflect structural conditions where the bedding planes dip and have no curvature. 'The La Brea-Parinas Concession is highly faulted by normal fault.. The beds are flat wherever exposed. The Parinas formation is approximately 635 ft thick. and it is etimated that 62 percent II the formation is effective sand. The original oil zone was about 565 ft thick. Fig. 211 presents an electric log showing typical Parinas sand development ill Mile Six pool. The Parinas band in Mile Six i. a well-sorted. medium- to-coal-se-grained. cross-bedded sand with minor lenses of shale and small lenses and pockets of pebble conglomerate. The sand grains are subangular to rounded and consist chiefly of quartz with feldspars. biotite hornblende, and augite as accessory minerals. Because of faulting of the Parinas- formation to the east and north of the pool. there is probably l possibility of a significant, natural water drive in Mile six. The faults within the pool. as indicated in Figs. 1 and 2. are of smaller disI,laceInent and seem to act only , partial barriers to fluid movement within the reservoir. RESERVOIR CHARACTERISTICS Core analysis data are available from five wells. The data were obtained from three wells (Nos. 3401. 3586 and 3719) at the time of their completion and from well 1996 when the original liner was sidetracked and the well was deepened ill 1946. Data from well 2779 were obtained in 1943 from old cores taken when the well was deepened in 1934. From these core analyses. the average porosity was estimated to be 22.6 per cent. and the average permeability to dry ail. was estimated to be 780 and Measured productility indices varied from 3.1 to 71.4 B/D per psi differential. Specific productivity indices varied approximately from 0.1 to 0.3 B./D per psi per ft of sand.

Jan 1, 1953

By W. S. Ayres

A BRIEF history of the growth of the anthracite-coal preparation will give a better view-point from which to judge the present problem of separating slate from coal. At the beginning of the commercial value of anthracite, 70 years ago, only the pure portions, or " splits," of the veins were mined and shipped to market, and without any preparation or screening other than the selection, while loading, of the glassy lumps, and the rejection of the fine material and the slate that had strayed accidentally into the coal. The next step was the crushing or breaking of the coal (hence the name Lt breaker" as applied to the preparation-building), and the sizing of it by means of bars or revolving screens. This stage of its development marked the advent of the "breaker-boy " as a slate-¬picker, with his ever-increasing capriciousness. As the richer veins or ? splits " became exhausted and the market demanded a still greater output, the less-pure " splits " and the thinner veins were utilized to produce the coal. Carrying as they do a far greater percentage of impurities; particularly when removing the pillars, it became necessary to build new and better equipped preparation-plants. Finally, we are now at the highest stage of complication yet known to the art of coal-preparation. We are dealing with varying specific gravities, frictional difference, hardness, structure, and form in the pieces of coal and slate coming from many different veins, and

Dec 1, 1909

By A. U. Seybolt, F. J. Norton

A standard technique for heat treating small metallurgical samples where no appreciable contamination from the atmosphere can be tolerated is that of sealing small samples in evacuated fused-silica tubes. Since vitreous silica is relatively impervious to diffusion of gases, even at temperatures approaching the devitrification range, around 1100°C, this simple procedure has been very widely adopted as a standard technique in metallurgical research. Many workers have recognized that, with metals of fairly high reactivity, insulation from direct contact with the SiOz envelope is desirable in order to avoid displacement reactions of the type M + SOz-- MOz + Si(in M). It is not so generally known, however, that the 'rate of permeation of oxygen from the air through the SiOz enclosure at tem-

Jan 1, 1964

By D. S. Eppelsheimer, D. N. Williams

The cold rolled textures of iodide titanium and of three samples of commercial titanium were examined using the Schulz-Decker Geiger counter technique. The iodide titanium and two of the three samples of commercial titanium showed a (0001) [1010] texture rotated 30' toward the transverse direction about an axis in the rolling direction. The third sample of commercial titanium showed a double texture. THE metals of the hexagonal system tend to deform similarly if the c/a ratios are similar. Thus titanium, zirconium, and beryllium, with c/a ratios of 1.601, 1.590, and 1.570, respectively,l should have similar cold rolled textures. The cold rolled texture of high purity iodide titanium has been described as (0001) [1010] rotated 30" toward the transverse direction about an axis in the rolling direction.' The texture of zirconium has also been reported as (0001) [1010] with a transverse rotation from the ideal position of approximately 30" about an axis in the rolling direction." This texture differs from that reported for titanium however since a continuous spread of (0001) poles toward the transverse direction was reported rather than distinct (0001) maxima 30" from the rolling plane normal. Beryllium has a texture similar to that of zirconium although the angle of transverse rotation of the (0001) poles is much less.' These three metals thus show a common type of cold rolled texture, as yet unexplained, which can be described as (0001) [1010] with various degrees of rotation toward the transverse direction about an axis in the rolling direction. Since titanium showed the greatest degree of rotation from the (0001) [1010] position, the cold rolled texture of titanium was re-examined using a semiquantitative Geiger counter X-ray technique to obtain more accurate experimental data from which a theoretical interpretation of this new type of hex- agonal rolling texture could be developed. The cold rolled textures of iodide titanium and of three samples of commercial titanium were determined. Table 1 gives the analyses of the titanium samples. Experimental Procedure Preparation of Samples: Prior to the final rolling operation each of the samples was given an initial reduction of approximately 50 pct and annealed to remove the gross effects of any previous treatments. Samples were annealed in vacuum, high purity helium, and air to determine whether annealing atmosphere had any effect on the cold rolled textures developed. All samples were annealed 1 hr at 800°C. Grain size determinations were made using the formula, 1.075 in which n is the number of grains counted in an area A (in sq mm) and M is the magnification of the area counted.' This formula gives the diameter between opposite flats assuming hexagonal grains. At least three areas containing more than sixty grains each were counted in each grain size determination. Rockwell B hardness readings were made on the annealed samples. The results of the measurements of

Jan 1, 1954

By Pradeep K. Rohatgi, Clyde M. Adams

Structures obtained on freezing of several hypo-and hypereutectic Al-Cu alloys over a range of solidification rates have been examined. Dendrite spacing, L, increases linearly with solute concentration and with the square root of the inverse freezing rate. The relationship for hypoeutectic alloys is: where rate of change of fraction solid with time, is freezing rate, C is solute concentration, (pct Cu)=1. Mass transport in inter dendritic liquid during solidification is analyzed; the experimental observations suggest maximum concentration differences and constitutional supercooling in the inter dendritic liquid increase with an increase in the solute concentration. The dendrite morphology changes with freezing rate and alloy composition. The dendrites of the a phase are parallel, uniformly spaced plates with slow freezing and rods with rapid freezing. Nonor-thogonal side branching has been observed in phases with cubic and tetragonal structures. Side branches in a dendrites are orthogonal with slow freezing and at 60 deg with rapid freezing. Formation of second-phase envelopes around the Primary phase is also discussed. DENDRITIC structure is characteristic of many types of phase transformation. The most extensively studied so far has been solidification of liquid solutions. chalmersl and coworkers have interpreted the formation of dendrites in terms of the breakdown of a planar interface. Most of the work done concerns itself with the development of an instability at the interface. Little theoretical work has been done quantitatively to relate the parameters of dendritic structure to mass transport in the liquid phase. A few empirical relations based on the experimental2'3 observations exist in the literature. Several workers2 including Brown and Adams1 have studied dendrite spacing in A1-Cu system as a function of solidification variables. In most cases, dendrite spacing has been found to increase linearly with the square root of some parameter proportional to the freezing time. The effect of solute concentration is not clear; some workers report the dendrite spacing increases with solute concentration4 whereas others report vice versa.''' ~ohatgi' has observed an increase in the spacing between ice dendrites with an increase in solute concentration in water. Tiller has also suggested that dendrite spacing should increase with solute concentration. In the present work dendrite spacing and morphology have been examined as a function of solute concentration and freezing rate. The freezing rate is defined as the fraction of liquid solidified per unit time, dfs/dß?, where f, is the fraction solid and 8 the time. The fastest freezing rate studied was 4550 times the slowest freezing rate. THEORETICAL CONSIDERATIONS It is of interest to analyze the concentration distribution in the liquid phase between growing dendrites during solidification, Fig. 1. Since this distribution is a direct consequence of the rejection of solute by the growing solid, a diffusional process, the concentration gradients increase with the freezing rate. However, when solidification rate is the only variable in a series of experiments, the interdendritic liquid regions become smaller (i.e., the dendrites become more closely spaced) with an increase in freezing rate. The main purpose of the analytical treatment of interdendritic liquid diffusion will be to reveal a tendency for dendrite spacing to decrease with increasing solidification rate in just such a way that the maximum concentration differences developed in the liquid phase are remarkably independent of freezing rate. Two rather different analyses are set forth, one pertaining to the one-dimensional diffusion which obtains in the interdendritic liquid between parallel plate-shaped dendrites, and the other to the cylindrically symmetrical diffusion around rod-shaped dendrites during early stages of solidification. The results of the two analyses are quantitatively similar, correlating dendrite spacing, maximum concentration difference, and freezing rate. First consider the simpler one-dimensional case. Two parallel plate-shaped dendrites are separated by a distance, L, between centers, Fig. 1. Solidification takes place by the thickening of these plates, with solute being rejected into the liquid. It is assumed there is no diffusion in the solid. This thickening process is slow enough and the dendrite spacing small enough that the concentration differences which develop, although interesting and important, are very small (an important assumption which is verified ex-

Jan 1, 1968

By John A. Church

Jan 1, 1903

By W. D. Robertson, R. E. Reed-Hill

Slip on (11221 planes, which do not contain a close-packed direction, has been identified on crystals strained at —190°C. Evidence is also presented to show that (1071) pyramidal slip is a mode of deformation at 25ºC in a limited orientation range. PYRAMIDAL slip (l011) <1120> in magnesium at elevated temperatures has been established for some time.1-2 More recently, Burke and Hibbard reported this mode of deformation at 25ºC, but their results were questioned by Craig.&apos; Also, as far as the present authors know, slip in magnesium on pyramidal planes of the second order, Type II (1122)) has not previously been reported, although Gilman"," identified (1122) slip in another hexagonal metal

Jan 1, 1959

By O. D. Gonzalez, R. A. Oriani

The migration of hydrogen and of deuterium dissolved in a iron and in nickel induced by an applied electrical potential has been measured over a range of temperature. In all cases the intevstitial solute migrates to the cathode. The deduced charges of transport are positive, independent of or slightly dependent on temperature, and markedly larger for the beavier mass. These results are interpreted as showing predominating momenlum transfer between electron holes and the acticated complex of the elementary diffusion act. THE migration of components of a metallic system under the action of an applied electrical potential is called electromigration or electratransport. This phenomenon has been known since 1861 and is becoming of increasing interest to metal scientists because of the opportunity it offers to explore the connections between mass transport and electron transport. Until recently, reliable data have been very scarce because of the difficulties inherent in the measurements. In addition, theoretical understanding has been either nonexistent or rudimentary and at present this situation is only moderately improved. Whereas the prevalent notion had been (and is still widely held) that electromigration directly reflects the state of ionization of a component in its equilibrium state in the metal, it is now becoming clear that the major, if not the sole, factor is the momentum transfer between the charge carriers, themselves in motion because of the applied field, and the metallic components in their activated state. It becomes important therefore to obtain reliable data over a range of temperature on electrornigration in systems where only one component moves, that is, either in pure metals (vacancy motion) or in interstitial solid solutions. Our choice of systems was dictated by our measurements&apos; of the Soret effect in solid solutions of hydrogen and deuterium in iron and nickel. Indeed, the main reason for making measurements on electromigration at all is that we suspected a mechanistic connection between thermal diffusion and electromigration. In our former paper&apos; we proposed that what is common to both phenomena is the momentum transfer between the charge carriers in the metal and the atom as it jumps from one equilibrium position to another. In Soret diffusion, however, there is in addition the dissipation of the energy of the jumping atom via pho-nons. We have since found that similar ideas for this interconnection have been developed by Fiks.2 In the present paper we will discuss in more detail our understanding of the mechanism of electromigration itself, but we turn first to a presentation of the experiments and results. EXPERIMENTS AND RESULTS Let us consider a metallic system in which only one component, m , can diffuse at the temperature in question, and to which are applied simultaneously an electrical potential gradient, grad cp, and a chemical potential gradient, grad p,. One may write3 for the material flux Jm and the electronic charge flux Je by applying the condition, grad = 0, to Eq. [I] and evaluating grad(um/T) for the isothermal case and for activity coefficient independent of composition over the relevant composition range. ere, c is the concentration and D the diffusivity of the mobile component. The experimental technique that we have used to measure Z* for the isotopes of hydrogen individually dissolved in each of two transition metals has been developed from a method used by Wagner and Heller.4 (A somewhat similar method was also used by Herold.5) A wire or thin rod of the metal under study connects two volumes of gaseous hydrogen at identical pressures; hence grad um = 0. A direct current is made to pass through the specimen, serving to maintain the specimen at the desired temperature and also to produce the electromigration of the hydrogen dissolved in the metal in equilibrium with the gaseous hydrogen. Under these conditions, the flux of hydrogen from one volume to the other is given, from Eq. [I] for grad( um/T) =0by

Jan 1, 1968

By E. W. Johnson, M. L. Hill

Equilibrium concentrations of hydrogen in iron were measured at H2 pressures up to 136 atm and temperatures down to 145°C. Residual hydrogen was prominent near 600°C in air-melted but not in vacuum-melted iron. The diffusible hydrogen solubility is abnormally high below 390°C, confirming the hypothesis of hydrogen trapping.&apos; It appears that the traps for hydrogen in iron form suddenly on cooling. The estimated H2 pressure in equilibrium with 5 ppm hydrogen in steel at room temperature is less than 1000 atm. It was shown previously1 that the diffusivity of hydrogen in a-Fe below 200°C is anomalously low, a behavior attributed to the presence in the metal structure of hydrogen "traps." The energy of the trapped hydrogen was computed as 4.8 kcal Per g-atom below that of the interstitially dissolved hydrogen. The strongest confirmation of the trap hypothesis should be obtainable from measurements of the hydrogen solubility at low temperatures. such measurements have been performed and are reported in this paper. The "residual hydrogen" effect1&apos;&apos; must be carefully controlled if valid measurements of the solubility are to be obtained, and such an effort was made in the present work. Previous data for the solubility of hydrogen in iron have been summarized by Geller and Sun.3 Their equation for the most probable solubility at 1 atm in a-Fe above 400°C is

Jan 1, 1962

By S. J. Aresco, A. A. Orning

This paper presents a scheme for determination of precision for the various steps in coal sampling, sample preparation, and analysis. It also gives resulting data on 100 American coals from various coal fields covering all ranks from lignite to low-volatile bituminous. The variances of the various steps of the process are studied as a function of the coal preparation, the top size of coal as sampled, and the ash content. To understand the variables that control the overall precision of coal sampling, sample reduction and analysis, there is need for measurement of the variances due to successive steps of the process. The purpose of the present paper is to study these variances as a function of the coal preparation, the top size of the coal as sampled, and the ash content. The sampling data included are from 100 individual preparation plants from various coal fields in the United States and cover all ranks of coal from lignite to low-volatile bituminous; various types of preparation; deep, strip and auger mines; and, in many instances, mixtures from two or more coal beds or types of mines. The collection of data is continuing, but sufficient work has been done to draw some important conclusions. Since the work was done in conjunction with the Bureau of Mines sampling of coal, the time that could be spent at any one preparation plant was limited. This, in turn, limited the number of samples that could be taken for each coal. For this reason, the results from various plants were pooled in blocks. Two major blocking categories were "raw" and "washed!&apos; The raw coals had no preparation other than crushing and/or screening. The washed coals were prepared further by some combination of wet or dry mechanical cleaning. The categories were further divided ac-

Jan 1, 1965

By Louis R. Hodell

WHEN the drilling of an oil well is completed a permanent opening from the reservoir to the surface must be provided. This is done by lining the hole with pipe, commonly known as casing. In the past, all but a small amount of casing has been run in the hole and joined by threads and couplings. Recently, however, in California, Texas, and Oklahoma, there has been a definite tendency &apos;to adopt -the welded joint for the following reasons: (1) Plain end casing for welding may be bought for 15 per cent less than thread-and-coupled casing; some of this is offset by the cost of welding the pipe in the hole but a respectable net profit remains.

Jan 1, 1937

By Willard P. Ward

HAVING been engaged during the past year in the manufacture of ferro-manganese in a blast furnace, I have imagined that some further information on this subject might be of interest to that large number of members of the Institute who are engaged in the iron and steel industries. The great question of the economical production of good steel, ingot metal, or homogeneous iron (we scarcely know now what to call it) from good materials, and at reasonable prices, has, thanks to the intelligence and energy of a few American engineers, been successfully solved in this country. Nearly all first-class railroads, and many that would riot rank so high, have adopted the Bessemer rail. Martin boiler-plates are rapidly gaining ground, in competition with

Jan 1, 1877

By H. F. Moore

DURING the last six years, there have been many extensive investigations of the fatigue of metals. The major work of &apos;these investigations has been the determination of constants for fatigue strength of wrought ferrous metals; but during the past year or two there have become available considerable test data on the fatigue strength of certain nonrferrous metals, including copper, brass, bronze, nickel, copper-nickel alloys, aluminum and aluminum alloys, magnesium and magnesium alloys. It is not proposed to give here extensive quantitative tables of test results; for such tables, reference is made to the published data of various laboratories. The following general conclusions, however, seem to be fairly well established: 1. The phenomenon known as "fatigue" of metal really a progressive fracture of metals. A minute (probably submicroscopic) crack is formed in the metal, the internat stress, is intensified at the ends&apos; of the crack, and under successive applications of load the crack spreads like a minute hacksaw cut until there is not enough sound metal left in the cross-section of the piece to stand the load. applied, and then failure occurs suddenly. 2. For wrought ferrous metals, there is .a limiting intensity of stress (as computed by the ordinary formulas of mechanics of materials) below which, a metal is able to withstand an indefinitely large number of repetitions of stress without failure. This limiting stress is known as the "endurance limit or the fatigue limit.? For reversed flexure, the endurance limit for. wrought ferrous metals is usually not far from 50 per cent. of the ultimate tensile strength.

Jan 1, 1925

By R. L. Orr, O. D. Sherby, J. E. Dorn

Creep data for pure metals at temperatures above those at which rapid recovery occurs (above about 0.45 the melting temperature) are correlatable by means of the equations and These correlations were applied successfully to data for aluminum, iron, nickel, copper, zinc, platinum, gold, and lead as well as for simple alloys. For a given metal, AH is a constant about equal to the activation energy for self-diffusion. THE early recognition that creep is stimulated by thermal activation prompted numerous investigators&apos;, &apos; to apply the same laws that are valid for the viscous behavior of liquids to analyses of creep data. To a good first approximation these laws are summarized by the equation were i is the creep rate; T, the absolute temperature; R, the gas constant in cal per degree per mol; T, the applied stress; AH, the activation energy in cal per mol; S&apos;, a constant dependent on the entropy of activation, the frequency of activation, and the contribution of each activation to the strain; and B&apos;, a constant dependent upon the size of the flow unit that is activated. Although Eq. 1 describes the flow of viscous fluids very accurately, its application to the creep of solids has been disappointing. Two reasons for the failure of Eq. 1 for creep are now known: First, the decelerating creep rates during primary creep demand that the internal structures of the metals are changing and that these changes might be reflected by changes in one or more of the three creep parameters S&apos;, AH, and B&apos;. Consequently when the conventional methods of evaluating these parameters are employed by comparing the secondary creep rates at a series of temperatures and at a series of stresses, the true effects of temperature and stress are masked because of simultaneous changes in one or more of the creep parameters. Second, as will be illustrated more fully later, three distinctly different types of investigations have shown that the stress term for high temperature creep enters the analysis as and not as t/T. This rather unexpected result points sharply to a significant fundamental difference between the mechanisms for the viscous behavior of fluids and the high temperature creep of metals. More recent extensive investigations",&apos;4 on the creep of high purity aluminum and several of its dilute a solid solutions have shown that where E is the total creep strain; temperature compensated time = for a constant temperature test; t, is the initial stress in a constant load test or the constant true stress in a constant stress test;" and t is the duration of test. • Eq. 2 is valid for either constant stress or constant load tests; but the total creep curve is difierent (i.e. the function, f, is differentl for each test. The fundamental origin of the validity of Eq. 2 is thought to arise from some equivalence of substructures in constant load creep tests at equal values of 0 or E. Both X-ray and metallographic examination revealed that practically identical lattice distortions and subgrain sizes are obtained for the same creep strain under the same load over wide ranges of test temperature.&apos; Furthermore the room temperature tensile properties following equal creep strains at different temperatures under constant loads were also identical, illustrating that identical substructures were indeed obtained.&apos; " A second type of correlation was obtained by differentiating Eq. 2 with respect to time, giving For the secondary creep rate, denoted by i,, But Eq. 2 reveals that 0, is a function of a, alone because the secondary creep rate in a given constant load test is always reached at a fixed value E,". Therefore where is the function that was introduced a number of years ago by Zener and Hollomon." Eq. 4 is not only valid for creep but will permit correlations between constant load creep and tensile data where e, is the rate of tensile straining and (TC is the engineering ultimate tensile strength.

Jan 1, 1955

By Stirling Huntley

With the threatened falling off in production of the lighter oil pools of the Tampico embayment in Mexico, a general search of that country for oil-producing regions has resulted in renewed activity in the region of the Isthmus of Tehuantepec, one of the first districts exploited in Mexico. Since the drilling of the first well in the San Cristobal section by the Pearson interests in 1902, drilling has been continuous, except during 1917-1921, when practically all development was stopped by the revolutionary activity. Early in 1921, a drilling campaign was inaugurated for the purpose of testing out the known salt-dome poolfi on the flanks of the salt masses, rather than on their tops where previous tests had been located. On Dec. 7, 1921, the Aguila Co., with which are consolidated the Pearson interests and which has been the only company active in developing this region, unexpectedly drilled into a sand horizon at 3015 ft. with its Conception well No. 18. The hole was unable to handle the production, as a 1400-ft. string of 121/2-in. casing was hanging in the hole, a salt-water horizon drilled through at about 800 ft., was not cemented off, and 3000 ft. of 4-in. drill stem with rotary bit was in the hole. This well&apos;s potential capacity was never determined, but it made 7000 bbl. of 25" Bé. oil through the bit and Pin. drill stem, in one of its sporadic flows before sanding up, and thus proved itself capable of the largest potential production of any well on the Isthmus. The well showed salt water before caving and sanding up with the drill stem still in the hole, and will probably never be used for production. Wells Nos. 22 and 23, drilled nearby, have proved disappointments after making good showings of oil. In the spring of 1922, Ixhuatlan wells Nos. 28 and 29, deep tests supposedly on the flank of the known salt cores in that field, went into solid salt; No. 28 at 2250 ft. and No. 29 at 2400 ft. No. 28 was continued in the salt for 1000 ft. before operations were stopped. Later comple-

Jan 1, 1923

By Stirling Huntley

With the threatened falling off in production of the lighter oil pools of the Tampico embayment in Mexico, a general search of that country for oil-producing regions has resulted in renewed activity in the region of the Isthmus of Tehuantepec, one of the first districts exploited in Mexico. Since the drilling of the first well in the San Cristobal section by the Pearson interests in 1902, drilling has been continuous, except during 1917-1921, when practically all development was stopped by the revolutionary activity. Early in 1921, a drilling campaign was inaugurated for the purpose of testing out the known salt-dome poolfi on the flanks of the salt masses, rather than on their tops where previous tests had been located. On Dec. 7, 1921, the Aguila Co., with which are consolidated the Pearson interests and which has been the only company active in developing this region, unexpectedly drilled into a sand horizon at 3015 ft. with its Conception well No. 18. The hole was unable to handle the production, as a 1400-ft. string of 121/2-in. casing was hanging in the hole, a salt-water horizon drilled through at about 800 ft., was not cemented off, and 3000 ft. of 4-in. drill stem with rotary bit was in the hole. This well&apos;s potential capacity was never determined, but it made 7000 bbl. of 25" Bé. oil through the bit and Pin. drill stem, in one of its sporadic flows before sanding up, and thus proved itself capable of the largest potential production of any well on the Isthmus. The well showed salt water before caving and sanding up with the drill stem still in the hole, and will probably never be used for production. Wells Nos. 22 and 23, drilled nearby, have proved disappointments after making good showings of oil. In the spring of 1922, Ixhuatlan wells Nos. 28 and 29, deep tests supposedly on the flank of the known salt cores in that field, went into solid salt; No. 28 at 2250 ft. and No. 29 at 2400 ft. No. 28 was continued in the salt for 1000 ft. before operations were stopped. Later comple-

Jan 1, 1923

By S. Tiwary, S. Samanta, B. N. Pandey, N. C. Saxena, R. Sinha, B. P. Nandy, B. Singh

Subsidence investigations over one bord and pillar and one longwall caved panel at Dhemomain colliery showed that, although the width-depth ratio (0.82 and 0.83) and working and strata conditions were almost identical, the maximum subsidence over bord and pillar panel was 46.2 per cent of extraction thickness against only 6.9 per cent over longwall panel. The angle of draw was 13O to 210 and 66 to 95 per cent of the subsidence had taken place immediately after extraction. The subsidence profiles were not symmetrical and were of funnel like shape. There was wide variation in subsidence movements over caved faces in India mainly due to difference in the composition of supercumbent strata.

Jan 1, 1983

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of March, 1913 BAECHTOLD, CHARLES A., Engr 9G Liberty St., New York, N. Y. BRANTLY, JOHN E., Instructor in Geology Tuscaloosa, Ala. CADDY, JAMES P., Net., ,Lake View & Star, Ltd Fimiston, West. Australia. LONERGAN, PHILIP J., JR., Prof. of Mining, Government University, Peking, China. MCKANNA, EDWIN A., Min. Engr P. 0. Box 834, Oklahoma City, Okla. MACDONALD, ANGUS W., Supt. Labor Dept., Dominion Coal Co., Ltd., 21 Queen St., Sydney, N. S., Canada. TSUBOI, Yoshio, Min. and Met. Engr., Kosaka Mine, Fujita Co., Akita-ken, Japan.

Jan 4, 1913