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By J. H. Anderson, G. A. Parks, B. K. Jindal

Both temperature and humidity are important variables in electrical separations. By independent control of temperature and water vapor pressure, it is shown that charge depends primarily upon relative humidity, not on temperature or water pressure alone. All the effects of temperature changes other than modification of humidity are apparently small. However, humidity control can be achieved through manipulation of the more tractable variable, temperature. Both temperature and humidity are important variables in electrical separations. Some of their effects have been described in general by Fraas1,2 and by Ralston.3 The influence of temperature and humidity may be considered a problem in industrial separations because humidity, especially, is not normally controlled, hence leads to unpredicted quality control problems. The problem is significant whether the separation is based on conductivity differences or on contact electrification. There is no doubt that water adsorbs from humid atmospheres onto mineral surfaces resulting in conductivity changes.'-8 An empirical relationship between conductivity and humidity is1.4-6,8 where a and b are constants peculiar to the substrate, and s and h are the conductivity and relative humidity respectively. Some authors have taken advantage of differences in a and b among minerals to make or propose electrodynamic separations in which h is the key control variable. Fraasl,2 reported that the charge developed on quartz and feldspar through contact with aluminum is sensitive to humidity, as illustrated schematically in Fig. 1. Lawver9 found that the charge developed by quartz on contact with several materials was tem-

Jan 1, 1967

By J. Alfred Berger, O. M. Katz

The Zv-Hf-H ternary system was studied between 500° and 900°C at pressures less than 1 atm of hydrogen gas between 1 and 60 at. pct H. A new and unique microgravimentric apparatus was used. Cizanges of slope on pressure-hydrogen composition isothernis delineated phase boundaries. These boundaries separatecl the three regions, a, 0, and y—so designated to correspond to the regions of the Zr-H binary system—from the multiphased areas between them. A eutectoidal decomposition was found with the ß region phase or phases decornposing into a lamellar product on quenching to rool ter,zperatuve. Reproducible decomposition-pressure hysteresis occilrved lnainly at lower hydrogen cornpositions and at lower temperatures across multiplzase vegions between a and 0 and a and y. Tire effects of hqfniur7z on the hydriding charactevistics of zirconiurrz weYe as follows: 1) stabilization of the a and y vegions while destabilizing the 0 region; 2) a/?preciable elevation of the decomposition pressrkres in the multiphase region between the a and /3 field; 3) ~nouenzent of the eutectoid reaction to high te~nperatures; 4) reduction in the total qiiantity of hydrogen absorbed under one atmospheve of Hz p7-essure; and 5) introduction of a split deconzposilion at the eiitectoiclal poinl in pa?? of the ternavy. Assuru~ptions based on an ir-2terstitial vandonl-solulion rtioclel 0.f hydrogen in metals slzowed that the bindit~g energy between solute sites prednnzinatecl at low /i?!dvogen concentrations. However, at high hydrogen contents the entropy was the predorninatlt factor in determining the stability of the Zr-Hf-H al1o.s. This was interpreted to mean a scarcity of filrtlzer itltevslilinl solute sites caused by hydrogen-hydvogen intet-actions in the metal lattice. INTEREST in the reaction of hydrogen with metals has increased in the past few years for the following reasons: 1) the formation or use of high hydrogen potential environments in nuclear reactors; 2) the reaction of hydrogen with alloys in nuclear reactors with the accompanying deleterious effects on the mechanical and corrosion properties; 3) the theoretical implications of thermodynamic data on the theory and rules of alloy formation in the metal-hydrogen systems; 4) the use of hydrogen-containing fuels in rocket engines; 5) the need for a process of making fine metal powders of high-melting reactive metals; and 6) the beneficial impregnation of superconducting alloys with hydrogen. In nuclear pressurized-water reactors, the problem exists of limiting the hydrogen pickup of zirconium alloys which are utilized as fuel cladding, heat shields, and support members. In general, zirconium alloys have good mechanical and corrosion-resistant properties in high-temperature water. However, hydrogen is absorbed from the corrosion reaction between metal and water, greatly accelerating the formation of the corrosion product ZrOz as well as mechanically embrittling the underlying metal. In addition, recent observations1 at zirconium to hafnium welds showed that secondary elements in zirconium can have an appreciable, and somewhat unexpected, effect on hydrogen absorption. This paper lists the thermochemical data in the range 500" to 900°C for the equilibrium reaction of four high-purity Zr-Hf alloys with hydrogen. Phase boundaries and thermodynamic functions are determined while the structural data will be presented in a future paper. In general, the Zr-Hf-H system approximates the well-known, eutectoidal, Zr-H diagram2,3 with modifications introduced through the behavior of hafnium.4,5 The Hf-H system,' published while this work was in progress, provided a consistent trend with the Zr-Hf-H data. PREPARATION OF Zr-Hf ALLOYS Table I presents a complete flow chart of the preparation procedure. The zirconium and hafnium crystal bars were completely immersed in high-purity kerosene and slowly cut into thin wafers. Wafers were then cold-sheared into approximately 1-g pieces, thoroughly cleaned, weighed, and inserted into the furnace. The alloys, B-2, B-4, B-6, and B-8, were then nonconsumable arc-melted under 500 mm of purified argon. Additional purification of the argon was accomplished by melting a large titanium button each time an alloy was re-melted or a different alloy melted. Each alloy button, which weighed 25 g, was remelted four times in an approach to complete homogeneity. Material losses were less than 0.02 wt pct. Alloy buttons were alternately cold-rolled and vacuum-annealed into 10- and 20-mil sheets. Table I1 gives the composition of the four alloys used. Very little elemental segregation existed be-

Jan 1, 1965

By T. S. Lovering

The Moffat tunnel passes through the continental divide about 50 miles west of Denver, Colo., on the Denver & Salt Lake R. R.: It is 16 ft. wide, 24 ft. high, and 32,383 ft. long, a distance of a little more than 6 miles. The advantages accruing from its construction may be briefly summarized as follows: The tunnel eliminates 27 miles of grade averaging more than 3.5 per cent. and actually running well over 4 per cent. in many places, and changes the steepest grade from 4.5 to 2 per cent. It reduced the peak of the railroad from 11,660 to 9249 ft. which enables one engine to pull four times as much freight as it could before the tunnel was built. If the Denver & Salt Lake R. R. completes its line, this road will shorten the distance between Denver and Salt Lake City by 200 miles and will have no steeper grades than the lines now connecting the two cities. The proposal to drive the tunnel through the divide dates back about 25 years and D. H. Moffat, who was the leading spirit in the organization of the Denver & Salt Lake R. R. spent much of his time and energy in efforts to raise money for the tunnel that bears his name. He was unsuccessful and died before the work was started. In 1920 an effort was made to obtain state legislation favoring a bond issue to finance three important railroad tunnels in Colorado but the measure was defeated, largely through the efforts of the citizens of the region near Pueblo. A few years later devastating floods caused the Pueblo voters to seek relief from the state and at this time they withdrew their objection to the tunnel bond issue. As a result, a $6,720,000 bond was issued to finance the Moffat tunnel. Construction bids were so high that the work was finally allotted on a scheme analogous to a cost-plus basis. The contract was awarded to Hitchcock and Tinckler, who are paid a fee of $140,000 for driving the tunnel. All bills are paid by the Moffat Tunnel Commission. The contract was let Sept. 19, 1923, and Hitchcock and Tinckler agreed to complete the work by July 19, 1927. In the event of finishing before this date they were to be given a bonus of $1000 a day and

Jan 1, 1928

By P. R. Kneitz, G. Yoshikado, D. Zayakov

The design and analysis of a circular, domed powerhouse for Pacific Gas and Electric (PG&E) Company's Kerckhoff 2 Project is described. Exploration, geologic stress determinations, mechanical properties, reinforcement and instrumentation are addressed briefly. The analyses of the circular, domed cavern and the comparison of predicted and field deformations are presented in somewhat more detail. The behavior of the completed powerhouse cavern has been found to be substantially as predicted by the analysis.

Jan 1, 1982

By D. L. Ritter, N. J. Grant, B. C. Giessen

Forty-six alloys covering the complete concentration range of the Nb-Rh system were examined by metallographic and X-ray methods; solubility limits of terminal ad intermediate phases and transformation and solidus temperatures were determined. There are nine intermediate phases; two eutectic, five peritectic, two eutectoid, and three peritectnid reactions were encountered. The experimental methods and the constitution diagram are described in Part I. Part 11 deals with the crys -tallography and relation of the intermediate phases. The Nb-Rh system was selected for study for three reasons: first, it was hoped that the anticipated similarity of the Nb-Rh phase diagram to the Ta-Rh1 and Ta-Ir2 diagrams treated earlier (see also Ref. 3) and to the Nb-1r4 diagram treated simultaneously would allow a crystallographic and comparative evaluation of the intermediate phases in these related systems; second, it was likely that the previous experimental methods could be carried over without significant change; and third, it was expected that the interesting mechanical properties of the a1 phase of the Ta-Rh and Ta-Ir systems would also be encountered in similar phases of the new systems, and that these phases could be investigated more closely. The phase diagram had not been treated fully in the literature; only brief surveys of some intermediate phases were found.5-7 It was attempted to cover the details of the phase boundaries, Part I, as well as to present the crystallography of the intermediate phases, Part 11. EXPERIMENTAL METHODS Specimen Preparation and Treatment. The following high-purity starting materials were used. 1) Niobium powder, 99.8 pct pure, mesh size -60 +200, from Wah Chang Corp., Albany, Ore. The analysis furnished by the supplier showed the following major impurities: Ta, <500 ppm; Zr, <500 ppm; 0, 300 ppm; Fe, 280 ppm; Ti, <I50 ppm; W, Si, <100 ppm; C, N, 30 ppm; all other impurities, <30 ppm. 2) Rhodium powder, ground sponge, 99.9+ pct pure, mesh size -80, from J. Bishop Co., Malvern,

Jan 1, 1964

By Louis S. Cates

At the annual meeting of the American Institute of Mining and Metallurgical Engineers in February, 1923, the Chairman of the Committee on Ground Movement and Subsidence appointed a sub-committee to work out a form of questionnaire and to collect data on subsidence and ground movement resulting from underground metal and coal-mining operations, and on ground movement and safe slopes in connection with open-cut metal-mining operations. The author was requested to take charge of the collection of data and the preparation of a questionnaire in connection with the Committee&apos;s studies of open-cut metal-mining operations. This paper is a summary of the work carried on and information received therefrom up to February, 1924. The first approach to the problem of safe slopes is to gather all information that pertains to finished slopes; in other words, the steepest economic angle from the horizontal that will stand in order to uncover the ores to be mined and be safe while the extraction of the ore at the base of these slopes is in progress. Whether or not this angle is 35" or 45" depends on many factors. The number of benches maintained to take care of falling rock and their height and width are direct functions of this overall slope. The slope is here taken to mean the angle from the top edge of the pit through the edges of the respective lower benches to the bottom of the pit. If we accept this definition of the slope, it might save some confusion as there would be a difference if one took the line from the top edge of excavation to the toe of the bottom slope. This latter slope would not be constant, but would vary with the number of benches. The depth of the various ore faces will vary, of course, depending on the deposit; Table 1 shows this to range from 50 ft. to 1100 ft. The geology is an important factor, as are the climatic conditions under which one is operating. A saturated condition in some rock structure causes rock flows; in the Panama Canal excavation, slides have run on a ratio of as low as one on ten, which is a 10 per cent. grade, or a slope of less than 6&apos; with the horizontal. Slopes as steep as 60&apos; have been noted in the Utah Copper operations, so that a wide divergence will possibly be met. The work of securing data that will be of value to the operator or estimating engineer will be difficult and will mean little unless a detailed

Jan 1, 1927

By J. R. Thoenen, M. C. Malamphy, G. K. Dale

The beginning of the war and the events leading up to it precipitated a near crisis in the aluminum industry. Demands for the metal reached proportions far beyond the prewar production capacities and, in addition, the submarine menace seriously curtailed the importation of bauxite from South America, hitherto a chief source of high-grade ore. The situation required an intensive search for domestic ore to augment the reserves and in October 1941 Congress directed the Department of the Interior to investigate the extent, mode of occurrence, and quality of bauxite in the United States. In December of that year the Bureau of Mines and the Geological Survey began the search for bauxite in Arkansas, where more than go per cent of the domestic ore had been produced and where the greatest amount of bauxite was known to occur. The program involves the geophysical and geological investigation of the Arkansas bauxite region and the core drilling of areas considered favorable for the occurrence of bauxite deposits. Cores taken from the bauxite-kaolin zone are sampled and analyzed in the Bureau of Mines laboratory in Little Rock. The information from each of the deposits discovered is then assembled, the bauxite is graded with respect to its possible utility, tonnage estimates are made, and the whole is presented in the form of a war minerals report. Thirty-eight new bauxite deposits had been discovered and investigated at the end of the calendar year 1944, and the presence of several others had been indicated by the drilling. More than 5000 holes had been drilled throughout the bauxite region, and more than 60,000 chemical analyses had been made of samples taken from the bauxite-kaolin zone. A study of the chemical analyses led to certain general conclusions not only with regard to the chemical composition of Arkansas bauxite, but also with regard to its component minerals. Charts and diagrams based on these conclusions have been developed for practical use by the Bureau of Mines: (I) to serve as a check against laboratory analyses, (2) to present tonnage estimates of ore bodies based on mineral composition, (3) to illustrate the relationship of tonnages of bauxite to the alumina, silica, and iron content, and (4) to serve as a control for mining operations by providing a means for quick estimates of the value of the ore from a partial analysis of its chemical constituents. The use of charts and diagrams similar to those discussed in this paper-- is not new. The use of the trilinear diagram for studying the ultimate analyses of coals as of proposed by Ralston in Bureau of Mines Technical Paper 93 (1915) showed that the various ranks of coal fell in different areas on the diagram and that volatile matter, calorific value and other properties could also be plotted by the use of contours. A considerable subsequent literature, largely on classification of coals, has accurnulated since then, showing the utility

Jan 1, 1948

By J. R. Thoenen, M. C. Malamphy, G. K. Dale

The beginning of the war and the events leading up to it precipitated a near crisis in the aluminum industry. Demands for the metal reached proportions far beyond the prewar production capacities and, in addition, the submarine menace seriously curtailed the importation of bauxite from South America, hitherto a chief source of high-grade ore. The situation required an intensive search for domestic ore to augment the reserves and in October 1941 Congress directed the Department of the Interior to investigate the extent, mode of occurrence, and quality of bauxite in the United States. In December of that year the Bureau of Mines and the Geological Survey began the search for bauxite in Arkansas, where more than go per cent of the domestic ore had been produced and where the greatest amount of bauxite was known to occur. The program involves the geophysical and geological investigation of the Arkansas bauxite region and the core drilling of areas considered favorable for the occurrence of bauxite deposits. Cores taken from the bauxite-kaolin zone are sampled and analyzed in the Bureau of Mines laboratory in Little Rock. The information from each of the deposits discovered is then assembled, the bauxite is graded with respect to its possible utility, tonnage estimates are made, and the whole is presented in the form of a war minerals report. Thirty-eight new bauxite deposits had been discovered and investigated at the end of the calendar year 1944, and the presence of several others had been indicated by the drilling. More than 5000 holes had been drilled throughout the bauxite region, and more than 60,000 chemical analyses had been made of samples taken from the bauxite-kaolin zone. A study of the chemical analyses led to certain general conclusions not only with regard to the chemical composition of Arkansas bauxite, but also with regard to its component minerals. Charts and diagrams based on these conclusions have been developed for practical use by the Bureau of Mines: (I) to serve as a check against laboratory analyses, (2) to present tonnage estimates of ore bodies based on mineral composition, (3) to illustrate the relationship of tonnages of bauxite to the alumina, silica, and iron content, and (4) to serve as a control for mining operations by providing a means for quick estimates of the value of the ore from a partial analysis of its chemical constituents. The use of charts and diagrams similar to those discussed in this paper-- is not new. The use of the trilinear diagram for studying the ultimate analyses of coals as of proposed by Ralston in Bureau of Mines Technical Paper 93 (1915) showed that the various ranks of coal fell in different areas on the diagram and that volatile matter, calorific value and other properties could also be plotted by the use of contours. A considerable subsequent literature, largely on classification of coals, has accurnulated since then, showing the utility

Jan 1, 1948

By Merle L. Bowser, Lawrence W. Scott, John N. Murphy

The environmental status of underground mining operations is critical to the health and safety of the miners; particularly in a large mine, the multitude of interacting parameters that can favorably or adversely affect the environmental status makes the manpower requirement of the routine checking of specific areas and conditions a formidable one. While the concept of environmental monitoring for miners has been considered for some time, until recently the availability of sensors to reliably measure the parameters of interest severely limited the utility of such systems. The status of sensors for mine use and the evaluation of enviornmental monitoring systems is reviewed.

Jan 1, 1980

By Howard R. Hughes

In drilling for water and oil to reasonable depths through the generally soft yielding clay and sand formation of the Coastal Plain of Texas, Louisiana, and Mississippi, the rotating method of drilling was adopted, principally on account of the easy and quick penetration, and the low cost of the drilling plant. In favorable ground, free of heavy gravel and rock strata, as much as 1,600 ft. has been drilled in less than 36 hr., although such performances were of course rare. Hydraulic rotary drilling, or, as it is now called, rotary drilling, was used in the above States as early as 1880. The plant consisted of an ordinary derrick, a 25-h.p. boiler, a small hoist, a steam pump, and a water swivel with hose attachment, and an ordinary flat diamond-pointed bit. The successful drilling in of a phenomenal oil well by this process on Spindletop, near Beaumont, Texas, on Jan. 10, 1901, and the ascertained impracticability of drilling subsequent wells in the same locality by other methods (owing principally to heavy quicksand under pressure from below), brought rotary drilling into great prominence, practically to the exclusion of any other process throughout the Coastal Plain, and later on elsewhere. The method, as its name implies, involves the rotation of a pipe by means of machinery placed on the derrick floor. A drill bit attached to the lower end cuts a clearance for the drill pipe, with much the same motion and effect as an auger. Water forced through the drill pipe by means of a pump, and escaping through the bit, removes the cuttings and returns to the surface outside the drill pipe. In this manner the hole is kept open, permitting the drill stem to rotate freely. The pressure of the column of muddy water holds up the walls of the hole until it has been cased. Practically all the wells of the Gulf coast region, numbering nearly 10,000, have been drilled with this system. During the last five years its use has been extended to many other States and countries.

Jan 1, 1915

By Arthur L. Bishop

INTRODUCTION Purpose The in-situ leach method for uranium extraction is a relatively new and innovative method of uranium mining. In 1975, the first commercial in-situ facility began operation in south Texas. Since that time numerous other operations have been initiated as either pilot or commercial ventures. Considerable literature has been published that deals primarily with generalities of the process or environmental concerns. Several federal agencies have published documents which do not reflect the true operating or environmental nature of the in-situ leach method of uranium extraction. From an environmental standpoint, this is also evident in the promulgation of rules and regulations. Hence, the purpose of this paper is to present experience with an environmental concern--non- production zone excursions--such that the industry and the regulatory agencies will gain greater insight devoid of preconceived ideas and misconceptions. General Process Description In south Texas, in-situ leach mining is utilized to extract uranium from permeable sandstone ore deposits 61 to 213 meters (200 to 700 feet) below the surface. Uranium is present as an insoluble uranium oxide. In the in-situ or solution mining technique, anoxidizing lixiviant is injected into the formation through injection wells. The solution reacts with the insol uble carbonate complex. This soluble uranium complex is produced at recovery wells, each containing a submersible pump. During production there is a constant sweeping of lixiviant through the formation from the injection wells to the recovery wells. Injection and recovery wells can be arranged in any of a number of geometric patterns dependent upon ore body configuration, aquifer permeability, and operator preference. Submersible pumps in the recovery wells pump the uranium rich pregnant solution to the initial processing facility. Monitor wells surrcsund the pattern area and are screened in appropriate stratigraphic horizons (production and non-production zones) to detect any lixiviant migration that may occur (Fig. 1).

Jan 1, 1980

By John S. Brown

As a part of a symposium on the relations of structure to ore deposition, in February 1938, the writer presented some tentative opinions derived from his experience with a number of important lead-zinc replacement deposits. These ideas were set forth, as a basis for discussion and a stimulus to further inquiry, in a mimeographed leaflet that read as follows Intimate acquaintance with a number of lead and zinc deposits in metamorphosed limestones seems to indicate the existence of certain common features from which can be established some general principles governing the localization of ore in this type of formation. It is suspected that these principles can be applied, with modifications, to mineralization in unmetamorphosed limestone. In metamorphosed formations, some observed rules are as follows: 1. Bands or masses of pure limestone are very resistant to replacement by ore solutions, and are likely either to contain no ore or to resist replacement until near the end of mineralization. The reason for this apparently is physical, not chemical, since microscopic data indicate that when ore is deposited by far the greater part of it substitutes for carbonate. The chief factor is believed to be a lack of porosity in massive limestone that has undergone flowage and recrystallization. 2. Masses of intensely siliceous or silicated rock are likewise unfavorable ore receptacles. This seems to be accounted for by two factors: (a) chemical unsuitability or resistance to replacement, and (b) physical resistance to small-scale brecciation, which might facilitate the opening of effective channelways for solutions. Some low-grade ore may occur, however, and also sporadic fracture fillings. 3. The optimum condition for ore reception appears to be found in bands or areas containing carbonate and silicates (or quartz) intimately mingled in something like equal proportions. In this situation movement is likely to result in mixed flowage and fracture, producing a fine-textured porosity that admits solutions freely and provides access to an abundance of replaceable carbonate. Cleavage cracks in some minerals such as diopside are believed to facilitate the penetration of solutions. 4. Certain minerals or assemblages are regarded as favorable impurities in a limestone and others as unfavorable. Original quartz, and subsequently developed diopside, and perhaps garnet, are typical favorable pre-ore gangue; in general rather equidimensional, brittle minerals. Tremolite, biotite, and probably wollastonite, are typical unfavorable pre-ore gangue; in general highly elongated and somewhat flexible minerals likely to develop under strong shearing stresses. 5. Tentative opinion is that the ratio of lime and magnesia in a limestone is of little or no importance.

Jan 1, 1940

By R. S. Archer

THE name molybdena was employed by Pliny to denote various substances resembling lead. Later this name was applied to galena-the naturally occurring sulfide of lead-or substances of similar appearance. By the middle of the eighteenth century, it was applied to graphite and to the mineral sulfide of molybdenum (MoS2) now called molybdenite. This confusion is quite understand- able inasmuch as these substances look and feel very much alike. In 1778, the Swedish chemist Scheele published a treatise in which he pointed out essential differences between graphite and molybdenite. On treatment with nitric acid, molybdenite, unlike graphite, produced a peculiar white earth with acidic properties which he called molybdic acid. Since the same mineral gave off sulfurous fumes on heating, he concluded that it was a sulfide of molybdenum. In 1790, there appeared an account of the isolation by P. J. Hjelm of the new element molybdenum, as a metallic powder, by heating the oxide with carbon. It was not until Bertelius conducted the necessary experiments, about 1818 to 1825, that the foundation of the chemistry of molybdenum was laid. The only recorded use of molybdenum during the first century after its isolation was as a chemical reagent, primarily for the determination of phosphorus. It was not until the last decade of the nineteenth century that the use of molybdenum in steel appears to have been investigated. A

Jan 1, 1953

By A. F. Peterson

MUCH has been said and written about the engineer shortage. The mining branch in engineering has lagged during the past several decades. I can think of two institutions, formerly prominent in that field, that have discontinued this department and another that has branched from a purely mining school into various forms of engineering. Conversely, I do not recall any institutions that have added mining to their curricula. I believe that this action is in direct response to the demands of incoming students. But I also believe that while there is a specific demand for civil, mechanical, and electrical engineers in the highly complicated mining operations of today, our need for mining engineers capable of assuming top responsibility for mining operations is unchanged.

Jan 3, 1957

By W. T. Thom

Interest naturally attaches to fissuring and subsidence of the earth&apos;s surface, whatever the cause may be, and the induced movement and fissuring of the impervious strata overlying an oil sand is of even greater practical importance because of its bearing upon the recoverability of the portion of the oil not already extracted or extractable by ordinary production methods. It is probably true that significant ground movement induced by oil production occurs only in oil fields in relatively young formations, where the oil comes from incoherent or only slightly cemented sands and oil-soaked clays, but inasmuch as a great proportion of our "gusher" wells produce from "running" sands and yield a large part of the total oil output, it seems worth while to make an effort to inspire the collection and recording of data indicating the nature and magnitude of oil-field subsidence, both surface and subsurface. Goose Creek Field The single known instance in which the nature and magnitude of the surface subsidence incident to petroleum withdrawal has been accurately ascertained is that in the Goose Creek oil field of Texas, described by Pratt and Johnson.&apos; There subsidence caused the submergence of a considerable area within the oil field, and, because the title to the naturally submerged lands of Texas rests in the State, it became necessary to determine whether the submergence was due to natural or artificial causes. A detailed study revealed that the sunken area conformed very closely to the limits of the productive oil field and that the cumulative depression over an eight-year period ranged from zero at the margin to 3.25 ft. at the center. This depression was accompanied by the development of local marginal surface fractures along which the subsiding ares

Jan 1, 1927

By John W. Wagner, Robert K. Willardson

Single crystals of Pbl-xSnXTe have been grown from The melt under liquid B2O3 using the Czochralski technique. The PbTe-SnTe crystals were grown from near-stoichiometric melts and from melts with slight deviations from sloichiometry. Crystal growth rates ranging from 1 mm per hr to 1 cm per hr were employed, the latter being generally used. Several investigations were performed to characterize the single crystals grown In this study. The phase diagram of the PbTe-SnTe system was examined. X-ray analyses verified the single-crystal character of the crystals, and powder pattern lattice parameter determinations showed that Vegard&apos;s law was followed within the limits of the experimental error. The as-grown crystals were p-type with apparent carrier concentrations of -8 x 1018 to -8 x 1020 carriers per cu cm. Hall coefficients, resistivities, and carrier mobilities were determined as a function of composition. Dislocations were revealed by an electrolytic etch, and the crystals were found typically to contain 2 to 4 x 105 dislocations per sq cm. Microhardness measurements were performed; no maximum in the Vickers hardness us composition curve was seen. Mass spectrometry was used for impurity analyses, and the crystals were found to contain 1 to 2 x 1017 total p-type impurities per cubic centimeter. Distribution coefficients were calculated for the major impurities which were Na, Mg, Al, Si, Cl, and Zn. RECENTLY interest has been stimulated in the preparation and characterization of many alloys of the binary compound semiconductors. This interest is due primarily to the almost unlimited possibilities of adjusting the semiconducting characteristics of these materials by varying the alloy compositions. One alloy system which has been receiving extensive investigation is the PbTe-SnTe system, since these alloys show promise of being useful as emitters and detectors of electromagnetic radiation in the spectral range of 8 to 14 µ. This paper reports on the growth of PbTe-SnTe single crystals by the Czochralski technique and investigations of the general properties of these crystals. The phase diagram of the PbTe-SnTe system was investigated so that specific alloy compositions could be attained. I) CRYSTAL GROWTH The PbTe-SnTe single crystals were pulled from the melt using the Czochralski technique. Generally, the crystals were grown from near-stoichiometric melts, although special growth runs were made from both lead-rich and tellurium-rich melts. Growth of single crystals from up to 5 pct lead-rich melts presented no problems; however, melts with tellurium in excess of -1 pct caused volatilization problems which generally made crystal growth impossible. All melts were prepared from high-purity materials as follows: 1) lead— 6 N— Cominco (Cominco Products, Inc., Spokane, Wash.); 2) tin—5N—Cominco; and 3) tellurium— 5N+— American Smelting & Refining Co., Plainfield, N.J. No further purification of materials was undertaken in this study. The elements were reacted at -1000°C in a vacuum-sealed silica tube for a few hours, a gentle rocking action being used to ensure thorough reaction. The cast ingots were then transferred to a silica crucible for crystal growth. A schematic diagram of the growth apparatus is shown in Fig. 1. The Vycor tube is sealed at both ends by O-ring flanges so that a vacuum or a positive pressure may be maintained in the growth chamber. The pull rod and crucible may be rotated; all crystals produced in this study were grown with the crucible sta-

Jan 1, 1969

Domestic: Middle West-,11.. B. Newcombe Eastern District-J. French Robinson1 Kansas-Henry A. Ley 2 Oklahoma-Henry A. Ley 3 Texas, except Gulf Coast and Panhandle-M. G. Cheney 5 Texas Panhandle-W. E. Hubbard and H. E. Crum 6 Gulf Coast-L. P. Teas 7 South Arkansas, North Louisiana and Mississippi-H. K. Shearer 8 Foreign Mexico-V. R. Garfias and C. 0. Isakson 9 Canada-Line M. Farish 10 Venezuela-C. W. Hamilton 10 Colombia-J. T. Duce 12 Peru-O. B. Hopkins 12 Trindad-Williaim J. Millard 13 Dutch East Indies-Fred B. Ely 13 Rumania-I. I. Gardescu . .. . 14 India-Eric J. Bradshaw 14

Jan 1, 1931

By G. S. Hume

ACTIVE drilling operations for oil were carried on during the summer of 1923 in various parts of, western Canada, particularly in Alberta. During the early part of the summer, interest centered in southern Alberta, in the Coutts area, just north of the producing Kevin-Sunburst field of Montana; but on Nov. 14 a strike of oil by British Petroleums Ltd. at its well near Wainwright, 120 mi. east of Edmonton, diverted public attention to a new field. According to present estimates, this well has a possible production of from 60 to 100 bbl. a day; the oil is 15° Be. with an asphaltic base and is obtained from a sand at the depth of 2019-2036 ft. The oil stands at 1700 ft. in the casing and there is sufficient gas pressure to cause it to flow when the well is opened. The oil horizon is in a sandstone in rocks of Colorado age. It is known that there is a terrace structure of which the western edge extends in a northwesterly direction from the vicinity of Hardisty to Viking, where it probably swings more to the north. At Viking a small dome-like structure on this terrace gives rise to an important gas field. Wainwright lies directly northeast of Hardisty. The exact structure in the Wainwright field is unknown. At Fabyan, 6 mi. northwest of Wainwright, the Imperial Oil Co.1 last year brought 1n a large gas well estimated at 14,000,000 cu. ft.; the escaping gas sprayed a small amount of heavy black oil over the derrick. The gas was obtained at a depth of 2727 ft., deeper drilling encountering a water sand. The results of drilling in the Wainwright field are encouraging for future development.

Jan 3, 1924

By Juan Sodi, John F. Elliott

The standard free energy of ReS2 has been measured in the range of 1050° to 1250°K using H2/H2S mixtures and a slight variation of the method described by Hager and Elliott.1 The result is: The experimental method and apparatus were modified slightly for this study. Measurements on Cu2S were made to verify the application of the method to the work on ReS2. THE EXPERIMENTS AND RESULTS Briefly, the experimental method consisted of exposing a chip of copper or rhenium at a known temperature for 8 hr to a slowly flowing gas stream at the same temperature in which Ph2S and PH2 were known. The chip was withdrawn quickly from the hot furnace, and subsequently it was inspected for the presence of a sulfided surface. In the experiments described here, there was no ambiguity in any case as to the presence or the absence of the sulfide. At a given temperature, gas compositions for sulfidization were explored systematically until two compositions were found whose values of ?G°, Eqs. [I] and [2], were within approximately 100 cal of each other, one of which was sulfi-dizing and the other was not. These are termed the "straddle" compositions and it is assumed that the equilibrium composition lies between them. The chief modification to the apparatus, which is shown schematically in Fig. 1 of Ref. 1, was to support the metal specimen on a small alumina boat which could be moved along the reaction tube, 6 mm ID, by platinum wires. An appropriate seal at each end of the reaction tube permitted the sample to be moved from the cold end of the tube into the hot zone in 2 to 3 sec, and the sample could be withdrawn equally rapidly. Thus, it was possible essentially to quench the specimen from the reaction temperature with the reaction gas or helium flowing and without danger of breaking the reaction tube. The usual practice at the end of the experiment was to switch the gas system to the helium tank, flood the reaction chamber with helium, and pull the sample out of the hot zone. The purpose of the modification was to permit study of the sulfidization of copper without the complication of the back-reaction between the gas and the specimen as the latter cooled during slow withdrawal of it from the hot zone; this was a problem in the earlier work.&apos; A further improvement located the tip of the temperature-indieating thermocouple and the specimen precisely at the hottest part of the furnace. A carefully calibrated thermocouple, with its tip at the position of the specimen and with other conditions duplicating those of an actual experiment, showed that in the temperature range of 900° to 1122°C the temperature of the specimen differed from that of the tip of the indicating thermocouple by less than 0.5°C. The two positions were 0.5 cm apart. The reaction gas was prepared from ultrahigh-purity hydrogen (<l ppm O2, <0.5 ppm H2O) and CP grade hydrogen sulfide (99.5 pct H2S). High-purity helium (99.995 pct He) was used. All of these gases were purchased from the Matheson Co. All flow meters were recalibrated by the soap-bubble method with hydrogen, H2S, helium, and several gas compositions used during the study. These calibrations gave a linear relationship with a slope of 1.0 for the plot of log flow rate vs log pressure drop across the flow meter, in accordance with the Hagen-Poiseuille equation. The analysis of the gas was determined in the same manner as was reported previously. Good checks were obtained between the composition of the gas established by the flow-meter settings and by chemical analysis of the gas taken after the mixing bulb and ahead of the furnace. The pressures of H2S, H2, S2, and HS in the equilibrium gas at temperature were calculated from the following data :3 The pressures of the species S and S8 were negligible for the conditions of the experiments.3 There was no sign of vaporization of ReS2 either by weight loss or deposits in the reaction tube. Thus it is not possible to account for the apparent volatility of the compound reported by Juza and Biltz.2 The inlet gas composition and the calculated equilibrium ratio of PH2 S/PH2 for the "straddle" points of each experiment are shown in Table I. The specimens of metal for the experiment were small clippings of annealed copper (99.9+ pct) sheet 0.005 in. thick that was obtained from Baker and Adamson and of "high-purity" rhenium (99.9+ pct) sheet 0.005 in. thick that was purchased from Chase Brass and Copper Co. A specimen was removed from the apparatus; inspected for the presence of the sulfide, and then stored in a sealed vial. A fresh clipping was used in each measurement. The condition of the surface of each specimen after the experiment is noted in Table I.

Jan 1, 1969

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

In the search for practical geological problems amenable to solution by the potential methods, the geophysicist is led to study mathematically various theoretical cases. In these idealistic discussions, the media under consideration are generally supposed to be homogeneous and iso-tropic. The geophysicist, of course, realizes perfectly that these conditions do not occur in their entirety in reality. However, the assumptions made are justified, because very often they are necessary in order to render possible an exhaustive study of a given problem, which otherwise would be too complicated, and would not lend itself to a complete mathematical analysis. Of the above two assumptions, that concerning the homogeneity of a given geological formation is satisfactorily realized except in so far as isotropy is concerned, since this property is not often encountered in practice. As a consequence, it is very desirable for the geophysicist to have quite an extensive knowledge of the properties of anisotropic formations, and of the laws that govern the propagation of electric current therein. With such principles in mind, he will be able to decide whether the conclusions arrived at in simple, isotropic conditions are still correct in more complex cases, or in what way they must be modified or adapted in order to constitute a sound basis for the interpretation of the results obtained in anisotropic media. On the other hand, the fact that in anisotropic formations the mobility of the ions is greater along the strike than perpendicular thereto can be utilized for determining the direction of the dip by induction measurements. We therefore propose to study in three successive chapters the following points: 1. Propagation of the electric current in anisotropic media. 2. Some consequences of the anisotropy of geological formations with reference to the surface electrical measurements, and their interpretation. 3. Determination of the direction of the dip of anisotropic formations by surface induction measurements.

Jan 1, 1934