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By Herbert Banks Johnson

During the past 10 or 12 years very little information has been made generally available concerning the commercial possibilities of separating materials by means of static electricity; and yet during that same period important improvements have been made in various branches of the science of electricity, which, when taken together, and applied to electrostatic separation, have resulted in important improvements in that art as well. For example, much improvement has been made in high-voltage electrical equipment such as full-wave vacuum-tube rectification and improved mechanical rectification. Great strides have likewise been made in the development of insulators for high-voltage work, not only in the materials used but also in the design of the insulators themselves. Again, in another field, the development of air-conditioning equipment has improved the technique of controlling the surface condition, through drying or humidifying, of the various materials that are passed through the electrostatic separator. In many authoritative publications and textbooks, the electrostatic separation process is declared to require a balance far too sensitive for general commercial application. For example, one publication1 in the past has referred to an unfavorable effect on the process caused by varying atmospheric conditions such as humidity. Some2 have even gone so far as to state that sunlight and shadows may seriously affect the separating efficiency of the process. Such statements may have been true in the early development of the art, when the source of static electricity was derived from a friction disk machine, such as the Wimshurst. The Blake Mosher equipment and the work of Huff in applying motor-generator sets, transformers and mechanical rectification overcame much of this kind of objection to the commercial application of the electrostatic separating process. Another objection made periodically is that it is generally considered necessary to feed the particles into the electrostatic field in a stream that

Jan 1, 1939

By Herbert Banks Johnson

During the past 10 or 12 years very little information has been made generally available concerning the commercial possibilities of separating materials by means of static electricity; and yet during that same period important improvements have been made in various branches of the science of electricity, which, when taken together, and applied to electrostatic separation, have resulted in important improvements in that art as well. For example, much improvement has been made in high-voltage electrical equipment such as full-wave vacuum-tube rectification and improved mechanical rectification. Great strides have likewise been made in the development of insulators for high-voltage work, not only in the materials used but also in the design of the insulators themselves. Again, in another field, the development of air-conditioning equipment has improved the technique of controlling the surface condition, through drying or humidifying, of the various materials that are passed through the electrostatic separator. In many authoritative publications and textbooks, the electrostatic separation process is declared to require a balance far too sensitive for general commercial application. For example, one publication1 in the past has referred to an unfavorable effect on the process caused by varying atmospheric conditions such as humidity. Some2 have even gone so far as to state that sunlight and shadows may seriously affect the separating efficiency of the process. Such statements may have been true in the early development of the art, when the source of static electricity was derived from a friction disk machine, such as the Wimshurst. The Blake Mosher equipment and the work of Huff in applying motor-generator sets, transformers and mechanical rectification overcame much of this kind of objection to the commercial application of the electrostatic separating process. Another objection made periodically is that it is generally considered necessary to feed the particles into the electrostatic field in a stream that

Jan 1, 1939

By E. G. Leonardon, C. Schlumberger, M. Schlumberger

Since the beginning of the year 1928 the senior authors and their associates have applied a series of procedures which makes possible the detailed study in situ of the formations traversed by a drill hole before the casing has been landed. They have given the name "electrical coring" to the ensemble of these processes, which now replace in a large measure the mechanical coring performed by the drillers, and permit the gathering of bottom-hole data hitherto unobtainable. Three years have elapsed since the technique and interpretation of these measurements emerged from the experimental stage and entered the field of industrial application on a large scale. The total length of drill holes so far surveyed by the authors and their associates, all over the world, amounts to several millions of feet. Practical and strongly built equipment has been evolved, which permits the examination in a short time of an open hole several thousand feet long. No comprehensive paper has yet been published discussing the essential principles of the processes applied and bringing into evidence their economic interest. This is the object of the present paper.' Numerous examples of field work performed under varied geological conditions are given, constituting a concrete illustration of the services rendered by the new methods. The study in situ of the formations penetrated by a drill hole is based on the measurement of a given physical factor or parameter associated with these formations. Generally the measurements are made systematically along the whole length of the open hole. The physical factors , or parameters which are now utilized by us to this end are: (1) the resistivities of the rocks; (2) their porosity; (3) their electrical anisotropy; (4) their temperature; (5) the resistivity of the muds. In order to

Jan 1, 1934

By J. Morgan Clements

Petroleum has been known in Japan since at least 668 A. D., for a picture shows the presentation, during that year, to the Emperor Tenchi (Tenji) of "burning water" and ('burning earth" by his subjects from Echigo Province, which today is the largest producer of petroleum in Japan. The burning water was doubtless petroleum and the burning earth either bituminous shale or oil-soaked earth or rock from near the oil seepages. The early methods of getting the oil were simple and similar to methods used today in Japan and in China. Where the seepages occurred, trenches or shallow wells were dug along the seepages and allowed to fill with oil, which was then bailed out; in some cases, they filled with oil and water and overflowed. During the 300 years following 1500 A. D., the use of petroleum in Echigo Province seems to have increased considerably, as compared with earlier centuries, and records show that in 1818 the depth of the wells had been greatly increased. Doubtless, they passed through the seepages and tapped the shallow oil-bearing strata; probably some of these deeper wells were dug before that time. The real value of petroleum was not recognized until early in the Meiji era, which began in 1868, when the Japanese learned that the kerosene that was being imported was derived from petroleum. Guided solely by information obtained from books, they refined the oil and increased the depth of their wells in order to increase the production. The deepest well, dug by hand, about this time was 894 ft.' (273 m.) and by 1874 the recorded production reached 3499 barrels. In 1876, Benjamin Smith Lyman prepared geological maps of the Echigo oil field, which were the first of such geological maps made in Japan, and based on these a more enlightened development of the oil fields began; the Japanese, however, still dug the wells by hand. Toward the end of the '80s) an American well-drilling outfit was secured, but the efforts to use it failed from lack of experience by the operators. In 1888, a complete well-drilling outfit was purchased and American oil-well

Jan 1, 1923

By J. Morgan Clements

Petroleum has been known in Japan since at least 668 A. D., for a picture shows the presentation, during that year, to the Emperor Tenchi (Tenji) of "burning water" and ('burning earth" by his subjects from Echigo Province, which today is the largest producer of petroleum in Japan. The burning water was doubtless petroleum and the burning earth either bituminous shale or oil-soaked earth or rock from near the oil seepages. The early methods of getting the oil were simple and similar to methods used today in Japan and in China. Where the seepages occurred, trenches or shallow wells were dug along the seepages and allowed to fill with oil, which was then bailed out; in some cases, they filled with oil and water and overflowed. During the 300 years following 1500 A. D., the use of petroleum in Echigo Province seems to have increased considerably, as compared with earlier centuries, and records show that in 1818 the depth of the wells had been greatly increased. Doubtless, they passed through the seepages and tapped the shallow oil-bearing strata; probably some of these deeper wells were dug before that time. The real value of petroleum was not recognized until early in the Meiji era, which began in 1868, when the Japanese learned that the kerosene that was being imported was derived from petroleum. Guided solely by information obtained from books, they refined the oil and increased the depth of their wells in order to increase the production. The deepest well, dug by hand, about this time was 894 ft.' (273 m.) and by 1874 the recorded production reached 3499 barrels. In 1876, Benjamin Smith Lyman prepared geological maps of the Echigo oil field, which were the first of such geological maps made in Japan, and based on these a more enlightened development of the oil fields began; the Japanese, however, still dug the wells by hand. Toward the end of the '80s) an American well-drilling outfit was secured, but the efforts to use it failed from lack of experience by the operators. In 1888, a complete well-drilling outfit was purchased and American oil-well

Jan 1, 1923

By Charles E. W. Bateson

The Mojave mining district is situated in a group of small hills centering around Soledad peak, in the Mojave desert, Kern county, Cal. These hills are about 4.5 miles SSW. of Mojave, a railroad town at the junction of the Santa Fé and Southern Pacific railroads. The town of Mojave is about 50 miles north of Los Angeles, to which it is connected both by telegraph and by rail. The distance on the Southern Pacific railroad is 102 miles, covered in 3 hr. and 45 min. by express train. A sketch-map of this region is shown in Fig. 1. The Mojave district is relatively isolated. The only other mining towns in this section of California are Randsburg and Johannesburg, in a district (containing the well-known Yellow Aster mine) at the northern end of a low range of hills, which begins about 20 miles NE. of Mojave, runs nearly N. for 35 miles, and varies in width between 3 and 6 miles. As will be seen later, the origin and formation of these hills are not the same as those of Soledad peak. II. Climate and VEgetation. The climate and vegetation of the Mojave district are typical of the arid regions of the southwestern United States. During the winter and spring there is some rainfall, and the tempera ture is generally from 60" to 70" F. in the day-time. The rainfall in the spring is often very considerable for short spaces of time, and cloud-bursts are not infrequent. In summer there is continual sunshine, with temperatures, as a rule, exceeding 100" F. in the day-time, while 115" F. in the shade of a house is not at all unusual; but at night the temperature falls considerably. No rain falls during the summer. The vegetation

Jan 1, 1907

By G. D. Boozer, W. H. Somerton

RESEARCH CORP., LA HABRA, CALIF. Thermal diffusivities of some typical sedimentary rocks have been measured by a rapid unsteady-state technique. Thermal data including diffusivity and conductivity are presented for the temperature range of 200" to 1,800°F. Diffusivities calculated from steady-state conductivity rneasurernents compared favorably with unsteady-state data at the lower temperatures. Unsteady-state data are less reliable at higher temperatures; reported values may be as much as 20 per cent high at temperatures in excess of 1,500°F. This is caused partly by the simplified method used in calculating diffusivity from experimental data and partly by the many thermal reactions which occur at the higher temperatures. The marked decrease in thermal diffusivity and conductivity at elevated temperatures indicates the importance of considering the temperature dependence of thermal properties in subsurface heat-transfer calculntions. Knowledge of the effects of liquid saturation, overburden and pore pressures, and heats of reaction of reservoir materials will be required before complete subsurface thermal analyses may be made. INTRODUCTION Heat-transfer calculations are becoming increasingly important in the analysis of in situ combustion and underground nuclear explosions. Thermal data for natural rock materials at elevated temperatures are generally unavailable. Calculations at high temperatures may be grossly inaccurate if temperature-dependent thermal properties of rocks are not considered. It is known that the heat capacities of rocks increase with temperature. Heat capacities may be calculated from chemical or mineralogica1 analyses of the rock system. Thermal bulk expansion of rocks is believed to be small, although few data are available. Thermal conductivities of most natural rock materials decrease with increased temperature. Thermal diffusivity, defined as the thermal conductivity divided by the product of the heat capacity and the bulk density of the material, is used in unsteadv-state heat-transfer calculations. It is apparent that thermal diffusivity decreases markedly with increased temperature. A new method, which gives a nearly continuous record of thermal diffusivity within the temperature range of 200° to 1,800°F and requires less than 1.5 hours for the run,' was used to measure the diffusivity of several sedimentary rocks. Thermal conductivities were calculated from measured bulk densities, heat capacities calculated from chemical analysis and the measured diffusivity values. Thermal conductivities were measured at lower temperatures by a steady-state technique1 to test the agreement of data obtained by the two methods.

By R. E. Jenkins

The Bell Canyon member of the Delaware Mountain group has yielded quite a large number of fields in which completion and production problems have been numerous and complex. Reserves are difficult to estimate due to the problem of evaluating the formation water saturation, and the feasibility of water flooding is questionable. Extensive laboratory investigations were undertaken to determine if normally measured rock and contained fluids properties could account for many of the peculiar characteristics of the formation. A statistical study or routine core-analysis data was made. Capillary-pressure data were obtained by several techniques. Fresh-water and brine permeabilities were measured and relative permeabilities of oil, water and gas were determined. Some qualitative wetta-bility tests were performed, and the petrography of a few thin sections was studied. The results of this work are presented, with typical or average data shown for each test. The permeability -to- water characteristic of the Delaware was found to be abnormally poor. Correlations of laboratory and field performance data indicate high water saturations in much of the formation. Pore geometry is highly uniform. INTRODUCTION The Delaware formation has undergone extensive exploration and development in the past few years. This has resulted in the discovery of quite a number of fields—producing oil for the most part. A large percentage of the productive wells have produced water along with the oil. Often there is no apparent pattern for the percentage of water cut experienced. In several instances vertical displacments of over 200 ft have been established between communicating wells in which the formation appears to be about the same, yet the structurally high wells yield a much higher water cut than the lower wells. Drill-stem tests have contributed little to well completion because they nearly always show small amounts of water (usually mud filtrate), regardless of what is produced later in the life of the well. Other formation evaluation methods have had no more than limited success in indicating ultimate productivity. Consequently, predicting the type of fluid productivity of Delaware wells has been very difficult. Hydraulic fracture treatments are almost universal, and unstimulated Delaware wells have not exhibited the productivity that normally would be expected of wells with the specific permeabilities encountered. Some operators have indicated that their Delaware wells need frequent re-stimulation. The uncertainty of reservoir water saturations reported for the Delaware has made difficult the task of evaluating oil in place in the reservoirs and estimating primary recovery. The unreliability of this data also will cause feasibility studies for water flooding or other secondary-recovery methods to be problematical. Several opinions have been voiced to explain why the Delaware performs as it does. Chronically poor well completions, dynamic water and tilted water tables, capillary inequi-libria, peculiar relative permeability characteristics and oil-wetness are among the suggested reasons. The dual purpose of this paper is (1) to describe the principal rock characteristics, and (2) to present an evaluation of those characteristics so that approaches can be made to explain the irrational behavior of wells completed in the Delaware. STUDY OF ROUTINE CORE-ANALYSIS DATA A statistical study of routine core-analysis data has been made to relate fundamental rock properties and characteristics of the formation to well productivity. For the most part, well production data were obtained from operators and augmented by production data from commercial information services. Only data which were available in detail and which were considered to be accurate were used. The core data used were obtained on samples from the perforated or open interval only and, thus, may not always represent the total productive interval in a well. All the core-analysis data included in this study are from the Bell Canyon member of the Delaware and were obtained by "plug-type" techniques, as opposed to whole-core or full-diameter techniques. Porosity values were obtained by the summation-of-fluids technique, permeability values are air permeabilities corrected for slippage to an equivalent liquid permeability, and the oil and water contents were determined by means of a high-temperature downdraft retort. All the procedures used are discussed at length in Ref. I. The core-analysis data were sorted

By B. Zondek, W. T. Cardwell, J. W. Sheldon

The fundamental equations that are used to describe two-phase fluid flow in porous media are Darcy's law for each phase and an equation of continuity for each component. The special case of one-dimensional, incompressible, two-phase flow has received much attention in the petroleum engineering literature.1-10 The basic paper on the subject is that of Buckley and Leverett.2 Buckley and Leverett showed that one could eliminate the pressure and obtain a single partial differential equation for the saturation. They solved this equation for the case when gravity and capillary forces are negligible. A frequently encountered property of the solution of the basic partial differential equation is that, as time progresses, the saturation becomes a multiple-valued function of the distance coordinate, x. Buckley and Leverett interpreted the formation of multiple values as an indication that the saturation-distance curve had be-come discontinuous. They developed a method of determining the position of the discontinuity from a material balance. We solve the Buckley-Leverett partial differential equation using the method of characteristics and the concept of shocks. Our treatment is analogous to treatments used in the theory of supersonic compressible flow." Although the numerical results obtained are the same as those obtained by previous methods, we believe that this approach is more logical and has broader applicability. It can, for example, be generalized to treat the case when the fluids are compressible. It is not clear how one would go about doing this using the method of Buckley and Leverett. To illustrate the power of the method of characteristics with shocks, we solve a problem in gravity segregation which has not been treated previously in the literature. A special case of the general method developed here was used by Welge, to solve a particular fluid displacement problem. We consider two-phase incompressible flow along the vertical direction x in a porous medium. We assume that there is no flow transverse to .x. We measure positive in the upward direction. The fundamental equations are obtained from Darcy's law and the mass conservation law. Since the two phases are incompressible, mass conservation is equivalent to volume conservation.

By M. E. Nicholson

The effect of boron on the austenitic transformation rate of iron is smaller than on low carbon steels. The influence of austenitizing temperature on B-Fe is the reverse of its influence on steels. THERE have been many studies made of the influence of boron on the hardenability of steel, but apparently none has been made of its influence on the y-a transformation of pure iron. There are several facts suggesting that boron should have a pronounced effect on the transformation rate of iron. First, Simcoe et a1.l indicated that boron reduces the nucleation rate of ferrite and bainite. Second, they showed, along with others,', " that the lower the carbon content of steel the greater the influence of boron on hardenability. If this trend extends to pure iron, the influence on rate of ferrite formation should be considerably greater for iron than for medium carbon steels. According to Rahrer and Armstrong," the multiplying factor for boron in pure iron should be about 2.40, compared with 1.50 in a 0.35 pet C steel. According to an extrapolation made by Grange and Mitchell,' the effect should be even greater, and the multiplying factor should be about 3.5 in iron. Many investigations of the boron influence'.7, 2, 5 indicated that boron is effective only when in solid solution. On the other hand, Chandler and Bredig" suggested that boron increases hardenability by combining with nitrogen, thereby preventing formation of AlN, which catalyzes the decomposition of austenite. If their hypothesis is valid, boron should have no effect on an alloy free from nitrogen. Digges et al." showed that so far as low nitrogen high purity Fe-C alloys are concerned this is not the case. No experiments, however, have been made on low nitrogen iron. To determine whether or not boron has an effect on low nitrogen iron and, if an effect exists, to determine whether it is as large as predicted from the investigations of boron treated steels, the following work was performed. Because of the rapidity with which iron transforms from austenite to ferrite at even a moderate degree of supercooling, it was decided to study the influence of boron on the transformation rate of iron by determining the effect of quenching rate on the temperature of the beginning of transformation. The technique, essentially that used by Greninger' and Duwez,H consisted of heating small specimens, 0.1 in. sq and 0.010 in. thick, in an atmosphere of purified helium with a resistance heater coil, and then quenching the sample in a jet of helium gas. At the time the jet was applied, the heating coil was removed from around the sample. The sample was suspended in the furnace on 30 gage chrome1 and alumel wires, one welded to each side of the specimen, which also served as a thermocouple for measuring the specimen temperature. Specimens were prepared from vacuum-melted iron obtained from the National Research Corp. which was rolled to a thickness of 0.060 in. and then decarburized in wet hydrogen for 51/2 hr at 700°C. This treatment also removed any boron present in the iron. The resulting iron contained 0.001 pet C. 0.0002 pet N, and 0.005 pet 0. One half of the piece was then boronized by surrounding it with 325 mesh boron powder and heating it for about 2 hr at 900°C in H,. The boronized iron was then homogenized at 1100°C for 24 hr. The iron boride case formed by boronizing was removed by grinding 0.010 in. from each side of the plate, and the piece was finally rolled to a thickness of 0.010 in. The resulting alloy contained

Jan 1, 1957

By T. Egleston

The origin of gold both in placer deposits ancl in veins, and especially the origin of nuggets, has been the subject of repctated discussions and investigations, which have been recently brought to my attention by several extremely interesting specinlens sent to me for examination, and mare especially by the one exhibited at the meeting of the Institute in February, 1880.* In the year 1874 I made some exan~inations of the hydraulic mines of California, and was very nluoh struck with the distribution of the gold throughout these deep placers, which were almost invariably poor on'the surface, while gradually growing richer towards the bedrock. The constant presence of fossil wood, and the large quantity of organic matter contained even low down in these beds, was also remarkable. Not being satisfied with the various theories advanced to account for the formation of these deposits, I began an investigation early in the pear 1879 on the conditions of solubility of gold and the causes of the loss in working gold ore in a large way. The researclles which I have undertaken show that gold must be considered a soluble rather than an insoluble metal, and that the conditions of solution are such as will be found anywhere where gold is likely to occur, and the solution may take place even under the ordinary circumstuncee of surfiace drainage, and may be going on freely even where the presence of gold has never been suspected, and that there are causee enough in nature to produce the solution of the gold in sufficient quantities to account for all the phenomena of both the vein and placer formations. The general theory with regard' to the formation of these placer deposits and nuggets has been that they were the result of the deatruction of pre-existing. vein-matter, which does not accord with the fitcts as sholvn in the deep placer deposits. The gold in such case would be distributed in layers of unequal richness throughout

Jan 1, 1881

By Yinchang Wang

1. INTRODUCTION 1. Subject, and Scope The formation of the oxidized ores of zinc has been recognized as a subject of great importance in economic geology. For many years these ores have been much sought, partly because they are more desirable for metallurgical treatment and partly because they are apt to be freer from gangue than is the sulphide of zinc. Up to very recent years the oxidized ores were the principal source of the metal and at present they still furnish a large portion of the commercial production. . The oxidized ores of zinc include six minerals, as shown in the-following table

Jan 9, 1915

By M. R. Annis, P. H. Monaghan

The control of mud properties affords two practical means of tnitigating pipe sticking caused by differential pressure: (I) teducing weight and, therefore, differential pressure; and (2) reducing the friction berween the pipe and mud cake. This paper describes investigation of the second of these—the friction between the pipe and the mud cake. Friction between a steel plate and a mud cake, held in contact by a differential pressure, was measured in the laboratory while maintaining a constant area of contact. Experiments were performed to determine how this friction varied with changes in mud composition and with changes in experimental conditions such as the differential pressure, time of contact of plate and mud cake, and filter-cake thickness. It was found that the apparent coefficient of friction, or the "sticking" coeficient, was not a constant; instead, it increased with increased time of contact between plate and mud cake, and with increased barite content of the Mud. The sticking coeficient varied from about 0.05 to 0.2 afer 20 , and eventually reached values of 0.1 to 0.3 after two Hours. Quehracho or ferrochrome lignosulfonate reduced the sticking coefficient at short .set times but did not reduce the maximum value. Carboxy-~t~etlz~lcellulose had no effect on the sticking coeficient. Emulsification of oil in the mud reduced the sticking coefficient. Some oils reduced the sticking coefficient to about one-third of its Value in the oil- free base mud, while other oils reduced it only slightly. Addition of certain surfactants with the oils further reduced the sticking coefficient. Spotting a clean fluid over the stuck plate caused a reduction in sticking coefficient only if the differential presslrrr was reduced, either temporarily or- permanently. INTRODUCTION Often during drilling operations the drill string becomes stuck and cannot be raised, lowered, or rotated. This condition can be brought about by a number of causes, such as sloughing of the hole wall, settling of large particles carried by the mud, accumulation of mud filter cake during long stoppage of circulation and, finally, sticking by pressure of the mud column holding the pipe against the filter cake on the hole wall. This paper is concerned with the last-mentioned phenomenon. Helmick 2nd Longley' in 1957 suggested that a pressure differential from the wellbore to a permeable formation covered with mud cake could hold the drill pipe against the borehole wall with great force. This situation occurs when a portion of the drill string rests against the wall of the borehole, imbedding itself in the filter cake. The area of the drill pipe in contact with filter cake is then sealed from the full hydrostatic pressure of the mud column. The pressure difference between the mud-column pressure and the formation pressure acts on the area of drill pipe in contact with the filter cake to hold the drill pipe against the wall of the borehole. Helmick and Longley also presented laboratory cxperiments which showed that the force required to move steel across a mud cake increased with increasing differential pressure and with the time the stcel and mud cake had been In cuntact. Their data indicated that replacing the bulk mud with oil reduced the force required for movement. Field evidence was rcported that spotting oil over the stuck interval sometimes freed the pipe. Outmans- in 1958 presented a theoretical paper which described the sticking mechanism and explained the increase of sticking force with time with equations derived from consolidation theory. Since publication of these papers, there has been interest in the differential pressure sticking of drill strings, and several mud additives to reduce sticking or special equipment to free stuck pipe have been proposed."" Haden and Welch" have recently reported laboratory evidence showing that the composition of the filter cake influences the force necessary to move steel on the filter cake. There seems no doubt that differential pressure sticking is a real phenomenon and that its severity depends on the magnitude of the pressure differential across the mud cake, the area of contact and the friction between pipe and mud cake. The mud weight required to control a well is determined by the highest formation pressure in the well: hence, the magnitude of the differential pressure opposite normal or subnormal pressure formations cannot bc reduced. The area of contact may be minimized in several ways (control of filter-cake thickness, use of stabilizers and spirally grooved drill collars), but there arc practical limitations which prevent reduction of contact area from becoming a complete solution of the problem. However. the mud composition might bc altered to reduce the friction between pipe and mud cake. This paper presents quantitative measurements of the friction between steel and mud filter cake and shows how the friction varies with mud composition for given experimental conditions.

By E. A. Gulbransen, A. Pebler

Pressure-composition isotherms have been determinedfor the systems ZrMo2 -H2 between 0" and 900°C at hydrogen pressures between 10-4 and 760 Torr. Tkese studies plus X-ray diffraction analyses of selected compositions show that these intermetallic compounds form a complete series of hydrogen solid solutions within this temperature and pressure range. The partial molar enthalpies and entropies of solution of hydrogen in the three intermetallic compounds were calculated. The solubility of hydrogen in these Laves phases can be related to their free electron concentration. ThE reaction of hydrogen with inter metallic compounds of zirconium with Laves phase-type structure has both theoretical and practical interest. The in-termetallic compounds have structures different from any of the pure metals. In addition the electron to atom ratio of the intermetallics varies appreciably. In the nuclear materials field, these materials are of interest since intermetallic compounds may exist as precipitates in commercial zirconium alloys with transition metals. From studies on the hydrogen reaction, one can establish the stability of the intermetallic compounds relative to the hydrides of the component metals. The intermetallic compounds may also be used as getters for hydrogen and as materials for hydrogen storage. This paper will present the results of equilibrium and structural investigations of the ZrCr2-H2, the ZrV2-H2, and the ZrMo2-H2 systems for the temperature range of 0" to 900°C and the pressure range of Torr to 1 atm. A complete thermochemical analysis will be made of the measurements. Some of the results have been referred to in a survey paper' covering the types of hydrogen behavior observed in zirconium alloys. LITERATURE ZrCr2 is the only intermetallic phase in the Zr-Cr system.' It exists in two allotropic modifications. Between 900" and 1000°C the hexagonal MgZa (C14) structure transforms into the cubic MgCu2 (C15) structure. Beck4 has previously shown that the intermetallic ZrCrz takes up hydrogen into solid solution up to a composition H/ZrCr2 = 1.14 at room temperature and 1 atm hydrogen. A ZrCr2 hydride was stated to have a fcc structure. The binary Zr-V system has been investigated by williams5 although Rostoker and Yamamoto 6 had given earlier a partial phase diagram. ZrV2 was the only intermediate phase found in the system. wallbaum7 reported earlier that the compound ZrV2 hp the MgZm (CJ4) type structure with a = 5.288A and c = 8.664A. This was not comfirmed by Elliot8 nor by Matthias, Compton, and corenzwit9 who reported that ZrV2 has a cubic MgCua LC15) type structure. The latter authors gave a = 7.429A. Also, several authors do not agree on the temperature of the peri-tectic horizontal. It appears that ZrV2 may exist in several modifications. A high capacity for occluding hydrogen was reported by Beck4 who found H/ZrV2 = 1.38 at room temperature and 1 atm of hydrogen. ZrMoz is the only intermetallic phase in the Zr-Mo system.10 ZrMoa is formed by a peritectic reaction of the melt with a molybdenum-rich solid solution. ZrMo2 has the C15-type structure with a = 7.59A. MATERIALS High-purity chromium, vanadium, and molybdenum were used together with grade 1 crystal bar zirconium to prepare the alloys. Table I lists the chemical analysis and the sources for the metals. Ten-gram alloy compacts were levitated and melted in an inert argon

Jan 1, 1968

By Franklin Moeller

CONSIDERING the really short time that has elapsed since hydro-metallurgical processes of extracting copper from ores have been extensively developed, and the large scale on which this method is practised at Ajo, the successful operation of the plant must excite the admiration of every visitor. The application of the mechanical unloader to the purpose for which it is employed at Ajo is but an extension of the use for which it was originally designed, some 20 years ago, for unloading iron-ore vessels at the lower lake ports. At a time when the maximum output of a single machine, with men shoveling the ore into buckets, did not exceed 40 tons per hour, G. H. Hulett invented and constructed a mechanical unloader with a bucket of 10-ton capacity. This machine was of the steam hydraulic type, and it is still in operation after nearly 20 years of service. Several more machines of the same type were built, but the difficulties of power transmission, and the rapid development of electrical machinery, soon led to the adoption of electrically operated machines, and practically all of the later installations have been thus equipped. This electrically operated unloader has proved so well fitted for the work that the design of the lake boats has been practically revolutionized, with special view to the ease and rapidity of unloading. It is now possible to unload a 12,000-ton vessel with four machines in a little over 2 hr. This has necessitated an increase in the capacity of the machine, and the largest yet built handles an average load of 17 tons, with a possible maximum of 20 to 21 tons.

Jan 8, 1918

By J. F. Bryson

Instantaneous outbursts of coal in underground workings have occurred frequently in various coal fields in Nova Scotia; British Columbia; Canada; South Staffordshire, England; and the states of Washington, Virginia, West Virginia and eastern Kentucky in the United States. Such outbursts in eastern Kentucky have been called "mountain bumps " because they are more likely to occur under mountain cover than elsewhere, but recently they have become generally known as "coal bumps." The eastern Kentucky coal field has been troubled by these outbursts since 1923. Many men have been injured and killed, and the morale of the workmen in the vicinity of such outbursts has been affected to such an extent that mine production has suffered for a considerable period following each outburst. Such phenonlenal occurrence in any coal field naturally has led to discussion as to the cause and means of prevention. In the eastern Kentucky field, local mine officials, workmen, mining engineers, and many others have offered many ideas as to the cause and many methods of prevention have been suggested, and tried without success. Some of the plans were either practically or economically unsound and in general impossible to follow. To enumerate all the suggestions would require a large volume. One cause mentioned was that they might be due to gas under high pressure, as in Lower Silesian mines, and the remedy reeommcnded was to drain the gas by drilling holes into a suspected area. A hole 30 ft. long was drilled into a 60-ft. pillar to allow the gas to drain off, hut the pillar bumped the next day. Realizing the importance of obtaining the best information available on coal bumps, the writer, with the permission of the Harlan County Coal Operators' Assoeiation, invited Mr. George S. Rire, Chief Mining Engineer of the U.S. Bureau of Mines, who had investigated bumps in several countries, to conduct an investigation of coal bumps in this field. Mr. Rice, by permission of the Director of the G.S. Bureau of Mines, accepted the invitation, and it was the writer's privilege, in company with

Jan 1, 1936

By Stanley C. Herold

Only two years ago there appeared in our technical magazines articles wherein it was shown that the application of back-pressure increased the ultimate production of a well, that edge water can be stopped in its encroachment by the injection of gas into the productive formation, with the consequent conservation of energy within the pool, that gas is the source of all energy involved in oil production, and that each pool has a definite minimum-valued gas-oil ratio to be attained for the most economical operation of wells. Today we are not so certain of these matters. Probably in some fields, under special circumstances, these ideas are correct, but certainly they must not be correct in all fields, under any and all circumstances. The nature of the productive structure, the location of particular properties on the structure, the existence of adjoining neighbors, whether these are higher or lower on the structure, and the methods of production followed by all operators on the structure, sand for sand on depth, make these subjects worthy of full consideration. Our difficulties in analyzing and comparing the performance of reservoirs in various parts of the world do not rest solely upon structural features and property lines. We do not complete the list of causes for these difficulties if we add lithologic features and correlation of strata encountered by the drill, with the magnitude of pressures exerted by fluids within any of these strata. A further cause, one which the author believes will complete the list, is one involving the theoretical mechanics of fluids within porous formations—porous in the nature of interstices in sandstones and some limestones, networks of fractures in shales, and cavities in otherwise compact limestones. The confusion of ideas concerning reservoir mechanics still with us today seems largely due to our failure to recognize among all wells three great divisions of theoretical mechanics, three great systems which are distinct in themselves, and according to which each well, or better, each group of wells, must be analyzed separately. These systems have been named by the writer Hydraulic Control, Volumetric Control and Capillary Control, respectively.' Wells in these controls behave dif-

Jan 1, 1930

By J. F. Bryson

Instantaneous outbursts of coal in underground workings have occurred frequently in various coal fields in Nova Scotia; British Columbia; Canada; South Staffordshire, England; and the states of Washington, Virginia, West Virginia and eastern Kentucky in the United States. Such outbursts in eastern Kentucky have been called "mountain bumps " because they are more likely to occur under mountain cover than elsewhere, but recently they have become generally known as "coal bumps." The eastern Kentucky coal field has been troubled by these outbursts since 1923. Many men have been injured and killed, and the morale of the workmen in the vicinity of such outbursts has been affected to such an extent that mine production has suffered for a considerable period following each outburst. Such phenonlenal occurrence in any coal field naturally has led to discussion as to the cause and means of prevention. In the eastern Kentucky field, local mine officials, workmen, mining engineers, and many others have offered many ideas as to the cause and many methods of prevention have been suggested, and tried without success. Some of the plans were either practically or economically unsound and in general impossible to follow. To enumerate all the suggestions would require a large volume. One cause mentioned was that they might be due to gas under high pressure, as in Lower Silesian mines, and the remedy reeommcnded was to drain the gas by drilling holes into a suspected area. A hole 30 ft. long was drilled into a 60-ft. pillar to allow the gas to drain off, hut the pillar bumped the next day. Realizing the importance of obtaining the best information available on coal bumps, the writer, with the permission of the Harlan County Coal Operators' Assoeiation, invited Mr. George S. Rire, Chief Mining Engineer of the U.S. Bureau of Mines, who had investigated bumps in several countries, to conduct an investigation of coal bumps in this field. Mr. Rice, by permission of the Director of the G.S. Bureau of Mines, accepted the invitation, and it was the writer's privilege, in company with

Jan 1, 1936

By J. Alfred Berger, O. M. Katz

Selected samples of hydrided Zr-Hf alloys were rapidly quenched to voom temperature and exrtrnined metallographically, by X-ray diffraction, and through micro hardness studies to confirm high-temperutuve data Confirming experiments sllowed that there were five phases in this Lernary system: 1) hextrgonal with lattice parameters similar to that of the initia1 Zr-Hf alloy but slightly enlarged due to dissolved hydrogen; 2) fee with properties of a brittle, intermediate, hydride compound; 3) fct with c/a crvoltnd 1.07 and which appeared as a neetilelike precipitale; 4) hexagonal, designated ?, with c/a ratio of 2.37; and 5) orthorhombic, designated X, with a = 4.67, b = 4.49, and c = 5.093 and whose tnicro-st?ruct~ival nppetrl-nnce depcncled o/i, heat lvecrt~r~ent. The tetragonrrl phase never crppeal-erl witkorct the cubic hydricle. Abpecrrtrnce of 0 and A also tlependet on the hafnium content of the zirconium. A previous paper' on the Zr-Hf-H system described the thermochemical data obtained with a high-vacuum, high-sensitivity mirrogravimetric apparatus. This data presented a fairly complete picture of the phase relationships at elevated temperatures. However, it could not establish the actual crystal structures, lattice parameters, or metallographic disposition of the hydride phases. The present complementary study utilizes X-ray powder patterns along with light and electron microscopy to characterize completely the five hydrided phases found in Zr-Hf-H alloys quenched to room temperature. Crystallographic features of the zr-Hf,2,4 zr-H,5-7 and Hf-H8 systems have been summarized in Table I. Designations of a, ß, and ? were retained in the Zr-Hf-H system for the phase regions through which the pressure-composition isotherms always sloped. However, it was not firmly agreed that these were single-phase regions.' In fact, the region designated y always contained a cubic as well as a tetragonal phase after quenching to -196°C. MATERIALS Preparation of the high-purity Zr-Hf alloys has been described.' The four zirconium alloys which were hydrided contained 37 wt pct Hf (23 at. pct), 51 wt pct Hf (37 at. pct), 73 wt pct Hf (58 at. pct), and 91 wt pct Hf (82 at. pct), respectively. These were designated B-2, B-4, B-6, and B-8. Photomicrographs of the initial alloys showed the material to be quite clean as would be expected from the precautions exercised in producing them. However, there were a number of annealing twins but no other subgrain structure. In addition to the four original alloys, fifteen hydrided samples were observed at room temperature. Hydrogen compositions are given at the top of Tables I1 to V. APPARATUS The phases present at elevated temperatures were studied by quenching hydrided samples to room temperature by two different methods, both under vacuum: 1) fast cooling of the sample tubes of the microgravimetric apparatus1'9 with flowing air and 2) rapid quenching into liquid nitrogen. The cooling rate for 1) was 750° to 250°C in 30 sec. Since the microbalance chamber was not designed to permit very rapid cooling of a hydride sample, all liquid-nitrogen quenching was done in an auxiliary experiment. The auxiliary quenching apparatus consisted of a small-bore, high-temperature furnace, a sealed SiO2 tube containing the sample, and a dewar quenching flask filled with liquid nitrogen. The hydrided sample, previously quenched in the microgravimetric reaction chamber, was placed in a platinum boat in a vacuum-degassed SiO2 tube. A zirconium wire getter and degassed SiO2 rod, to reduce the internal volume, were also in the tube. After sealing the tube under vacuum the zirconium getter was heated to absorb the last traces of gas. Only the sample was heated at the reaction temperature for the desired length of time, and then the tube dropped through the opposite end of the furnace into the dewar. A quenching rate of 200" to 400° C per sec was estimated. Analyses of samples after the auxiliary experiment also showed practically no increase in oxygen or nitrogen content from heating in the SiO2 tube. All of the samples were examined at room temperature by the X-ray powder method. The majority of the powder patterns were obtained with double nickel-filtered CuKa radiation after 8- and 16-hr exposures in an 11.48-cm-diam camera. Cobalt and chromium radiation were also used to spread out the high d value end of the Pattern. Such patterns readily identified the minor phases. NO oxide or nitride lines were found. Where sharp back-reflection lines existed it was possible to reduce the

Jan 1, 1965

By F. A. Forward, A. H. Ross, J. Halpern

IN treating carnotite ores by carbonate leaching it is often necessary to subject the ore to a prior roast. Among the advantages that may result from roasting are: 1) improvement in settling and filtering characteristics of the ore; 2) destruction of carbonaceous impurities that would otherwise contaminate the leach solution and consume carbonate reagent; and 3) substantial increase in extraction of vanadium, which is usually low when the un-roasted ore is leached. Recovery of vanadium may be an important factor in processing carnotite ores, and the fact that vanadium is usually recovered in good yield by acid leaching has often been an economic advantage over results obtained with carbonate leaching. It has been found that response of an ore to carbonate leaching, following roasting, depends primarily on its composition and on the conditions of the prior roast treatment, particularly with regard to the roasting temperature, the atmosphere maintained above the charge during roasting and cooling, and the presence of certain reagents. These factors, especially the last, virtually determine the extractions of uranium and vanadium attainable by carbonate leaching, as well as the reagent consumption on leaching, whereas adjustment of the leaching conditions has only a limited influence. These variables were examined systematically to elucidate roasting and carbonate leaching of carnotite ores and to establish a treatment yielding high recoveries of both uranium and vanadium. Tests were conducted on samples of four different Colorado Plateau ores, described in Table I. Roasting Procedure: The roasting tests were conducted in an electrically heated furnace in which the temperature was controlled to +15oC. The ore (usually a 500-g charge) was ground to —100 mesh, mixed with the desired reagent, and spread in a silica tray to a bed depth of about 1/2 in. During the roast the charge was rabbled at intervals of 15 min. To provide free access of air the furnace was usually ventilated; however, in a few experiments a controlled atmosphere such as carbon dioxide or hydrogen was maintained above the charge. Leaching Procedure: The pulp, generally comprising 500 g of ore and a 2000-cc solution containing 80 g per liter of Na2CO3 and 20 g per liter of NaHCO3, was agitated in an autoclave at 120°C, under 30 psi O2. Samples were withdrawn periodically, and the solution and ore residue were analyzed. Under the conditions employed, maximum attainable extractions were generally achieved in 4

Jan 1, 1958