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By G. W. Doepel, W. P. Sibley

A three-dimensional, multilayer, mathematical model has been developed for predicting performance by mis-c.ible displacement. Areal and vertical coverage, total gas-oil ratio, propane-oil ratio and oil-recovery factor for the multilayer system are computed as functions of hydrocarbon pore volumes of solvent injected. The technique has been programed for use on the IBM-7090 digital computer and was used in calculating perfortnance for continuous miscible displacement of a five-spot, 50-layer .system. Results reported are based on the use of published laboratory data for a single, uniform five-spot layer. However, the technique is sufficiently generalized to calculate performance of any system of layers of any pattern configuration and mobility ratio, provided data are available to describe perfortilance of a single layer. The technique has also been adapted for predicting oil recovery resulting from various gas-driven slug sizes. The results presented for both continuous and slug-type injection show, that permeability variation has 0 significant effect on oil recovery but that solvent composition, within the range studied, has a lesser effect on oil recovery. INTRODUCTION Experience from many of the miscible-phase displacement projects currently in operation indicates that the injected solvent flows preferentially through the more permeable zones in the reservoir. This preferential solvent flow in the high-permeability streaks results in a reduction of vertical coverage (C,) and an attendant decrease in oil recovery. The multilayer technique presented in this paper uses areal coverage (C.,) data for a single layer from the literature and from laboratory measurements of displacement efficiency (herein referred to as microscopic coverage, C,,) to calculate areal coverage (C,) and vertical coverage (C,) for the multilayer system. Oil recovery for the multilayer system is obtained as the product of (Ca) (Cm) (Cv). It is assumed that C, in a single layer is 100 per cent; therefore, (C,) (Cm) is a measure of oil recovery from that layer. Data presented in the literature for a single layer generally deal only with areal coverage and/or microscopic coverage —but seldom specifically with oil recovery. Nevertheless, this technique is flexible in that either Ca and C,, of an individual layer or a direct measurement of oil recovery for the layer may be used. In developing this technique, the problem arose concerning a method of determining the relative amounts of solvent that will enter each layer during any increment of solvent injected. To solve the problem, a dimensionless equation was derived for expressing solvent injected into each layer as a fraction of total injection. A finite-difference method was applied in integrating the equation to determine oil recovery for the system of layers as a function of pore volumes injected. The technique subsequently was programed for solution on a digital computer. The method was applied to predict performance of a deep California reservoir under continuous miscible displacement and has been extended for calculating oil recovery as a function of slug size for gas-driven slug injection. The technique may be applied to any petroleum reservoir that can be adequately represented as a layered system, by considering permeability variation,1-3 permeability range and average permeability. Each layer is then assigned its appropriate permeability, porosity and hydrocarbon saturation. RESERVOIR VOLUME CONTACTED BY SOLVENT It has been recognized for some time that high microscopic coverage (C,) can be obtained by injecting a miscible agent, such as propane, into an oil reservoir. These high values of C,,, have been demonstrated in the laboratory and are normally between 80 and 100 per cent, depending on solvent and reservoir oil composition as well as on reservoir temperature and pressure. In miscible-phase displacement, because there is no interface between solvent and oil, effective permeability to solvent is the same as that to oil. (This assumes that oil saturation has not changed and that water is immobile.) Consequently, mobility ratio (M) simply reduces to that of viscosity ratio . Perrine4 and Habermann5 have shown that large

By J. B. Cheatham, C. E. Murphey

Presently, computer control of Borobolic direction cannot be obtained during drilling, and most straight-holc drilling methods attempt to resist hole deviation rather than control direction. Many of the theories advanced as possible explanations of the cause of hole deviation are Summarized berein. A new correlation of physical partables is introduced to indicate bow factors such iis drill collar stiffness clearance and hit weight influence borehole deviation, .A methord is proposed for predicting the rate of change of hole angle when drilling conditions are changed. INTRODUCTION Control of borehole direction during drilling can be difficult and costly. Unintentional crooked holes are often lrilleti in dipping formations and many times directional drilling is required when the surface location is not directly above the target area —- for example, at offshore and mountainous locations. Prilllng progress can be greatly hindered in either air or liquid drilling when it be comes necessary to use low bit weight to prevent excessive hole angle build-up. If hole inclination becomes too great, drill pipe drag becomes excessive and fishing risks are increased, logging is more difficult and problems of differential sticking, key seating and fatigue failures may be encountered. Dog-legs and key seats are more serious problems than steep inclination angles: therefore, reducing rate of direction change is preferred to attempting to maintain absolutely vertical holes. Consequently, a straight inclineti hole is preferable to a nearly vertical crooked hole containing numerous dog-legs. In this paper, theories of the cause of hole deviation and analyses of drill string behavior under down-hole conclitions are summarized. Methods for computing hole deviation are presented und systems for resisting deviation as well as neans for provic!ing control of holt- direction are iliscusseI. A new correlation of physical variables is introduced tu indicate how factors such as drill collar stiffness, clearance and bit weight influence borehole deviation. A method is oroposeti for predicting the rate of change of hole anFrle when drilling conditions are clianged. IIEVIEU' OF PREVIOUS WORK ON HOIaE DEVIATION Significant progress in the theoretical analysis of hole deviation problems has been made in the past 1 5 years. The pioneering work has been primarily a result of the efforts of Lubinski and Woods.l-5 In 1950, Lubinski 1 considered the buckling of a drill string in a straig:rt vertical hole, a problem also considered by Willers6 in 1941. It wns concluded that very low bit weights must be used to prevent hole deviation resulting from drill collar buckling. The use of conventional stabilizers was proposed2 in 1951 by Mac Donald and Lubinski as a method for permitting greater Sit weights to he carried without drill collar buckling. These authors pointed out that a 2° nearly vertical spiral hole can cause severe key seatinp, and drill pine near, wilereas n 3 straight inclined hole with deviation all in one direction, while not vertical, will not result in serious drillirig or producing problems. Studies were continued with an investigation of straight inclined holes by Lubinski and Woods3 in 1953. In this paper they concluded that perfectlv vertical holes cannot be drilled even in isotropic forriations unless extremely low bit P-eights are used. .l'l~ey postulated that constant drilling conditions produce holes of constant inclination angle and varying conditions cause the hole to drill at a neiv equilibrium angle. This analysis was not concerned with drill string buckling since it was based on an equilibrium solution in which the ~irill string Was presumed to lie along the lower side of the hole abcrve the point of tangency. Weight of the drill collars below the point of tangency tends to force the hole toyard the vertical, whereas the weight on hit tends to force the hole aurav from the vertica l. The concept of an anisotropic formation Lvas introduced as an empirical method for explaining actual drilling data and as a means for extrapolating known deviation data to otiier conditions of hit

Jan 1, 1967

By D. A. Dahlstrom

In the paper, a comparison was made between flowsheets using the screen bowl centrifuge and disc filters, respectively, as the primary dewatering device. The authors very effectively show that by raising feed temperature, mechanical dewatering is enhanced through reduced viscosity of the water. When a final coal moisture of 10% is required, the net effect of heating the feed is a reduction in thermal requirements because of the lower evaporated load on the dryer. The flowsheet comparison on this, however, was not completely correct. Disc filters do not generally utilize enhanced mechanical dewatering through increased temperature. Horizontal belt filters, through the optimal use of steam heating of the filter cake, have shown significant cost reductions over disc filters where steam is not used. In addition, the authors forgot to mention that there is a certain fraction of the feed that is so fine that it cannot be recovered by the centrifuge economically. That is the function of the filtration device shown in [Fig. 4]. In subbituminous pipeline coals, this fraction represents more than 10% of the feed. Even after flocculation and belt pressing, the moisture content in the fine fraction is 30%-40. Recent tests on a subbituminous pipeline coal slurry, compared an Eimco-Extractor horizontal belt filter with the screen bowl centrifuge flowsheet shown in [Fig. 4]. Mechanical dewatering was enhanced through the use of a steam dry zone after the initial dewatering zone. Vacuum pump horsepower was reduced by more than 50% through the use of condensers, and heat recovery was utilized to minimize thermal costs. Thermal drying to 10% moisture by weight was required in both flowsheets. The 0.5 wt% fines in the filtrate were flocculated and recycled to the filter, thus eliminating the belt press and solids mixers. When the three major operating costs (which normally account for 50%-75% of the coal operating costs) of steam, electricity, and flocculants at current prices were calculated, the flowsheets utilizing the Eimco-Extractor had cost savings vs the centrifuge flowsheet of 89c/t (81c per st) of surface dry coal. This advantage increases with increasing thermal and electricity prices. I congratulate the authors for the strides made with the screen bowl centrifuge. However, filtration flowsheets continue to be improved and their simplicity and low thermal and electrical requirements should not be so quickly dismissed.

Jan 1, 1984

PROF RICHARD ÅKERMAN Stockholm, Sweden SIR LOWTHIAN BELL Middlesborough, England DR THOMAS M DROWN South Bethlehem, Pa PROF HATON DE LA GOUPILLIERE Paris, France PROF HANS HOEFER Leoben, Austria PROP DR BRUNO KERL Berlin, Germany M FLORIS OSMOND Paris, France PROF DIMITRY CONSTANTIN TSCHERNOFF St Petersburg, Russia PROF DR HERMANN WEDDING Berlin, Germany

Jan 1, 1910

By LEWIS F. THOMAS

MINING geologists and mining engineer, rarely give due thought to the geography of mining deposits. They realize, it is true that what may be ore in one place would be only worthless rock in another because f the in accessibility of a smelter r a market; and they may consider the lack of a supply of labor, or water, or power to carry on operations. But they do not think (of these things in terms of geography. Geography may be defined as the science of relationships between earth and man, so geographers are vitally interested in the how and why of mining as it is carried on at different place, having entirely different environment-. Such environments are geographic complexes or composites of natural and cultural elements, which are listed and briefly discussed in the following paragraphs.

Jan 1, 1941

By T. S. Plaskett

A striated structure perpendicular to the growth axis was observed by the copper-decoration tech-nique in dislocation-free, .float-zoned silicon crystals. The striations, which were spaced about 100 p apart, fitted the relationship d = f/u , where d is the spacing, f is the growth rate, and u is the crystal rotation rate. Each stria was resolved into an UNDOPED silicon crystals pulled from quartz crucibles by the Czochralski technique usually exhibit a striated structure perpendicular to the growth axis.'-' This structure has been attributed to oxygen segregation, with the oxygen being introduced from the quartz crucible. If the crucible is rotated, the level of oxygen contamination has been reported as high as 10° atoms per cu cm.10 These striations are similar to solute striations commonly observed in doped Czochralski-grown crystals. The periodic nature of the striations is caused by a periodic variation in the growth rate",12 which is attributed mainly to thermal gradients in the melt.13 A finer striated structure14 attributed to constitutional supercooling is sometimes observed between the coarse striae. The oxygen striations have been observed by infrared transmission techniques,' by the copper-decoration technique,' by X-ray diffraction microscopy,6-8 and by 9 p absorption measurements3 on crystals pulled from the melt both with and without dislocations. In this investigation float-zoned dislocation-free crystals were examined by the copper-decoration technique. The level of oxygen for float-zone material is less than 1016 atoms per cu cm the lower limit of detection by 9 p absorption measurement. EXPERIMENTAL TECHNIQUE The crystals were grown by the float-zone process with the rf heating coil outside of the quartz envelope containing the silicon. All float zoning was done under an atmosphere of purified helium. The Dash technique15 was used to grow the crystal dislocation-free. This involves growing the crystal initially with a diameter between 2 and 3 mm and at array of starlike precipitates of copper. The strucLure was not .found at the surface tor a depth of about 1.5 mm, or in a region of similar width ahead of a dislocation network. The structure is postulated to consist of vacancy clusterings or dislocation loops. very rapid rates, about 20 mm per min, for a distance of about 3 cm. The diameter of the crystal is then increased to the diameter of the source of silicon, which in this case was about 19 mm. Because of the arrangement of the apparatus, the zone was passed downward rather than upward, contrary to the standard float-zoning practice. Also, the source was rotated rather than the seed. ziegler17 has made dislocation-free crystals by a similar technique but has passed the zone upwards. The starting material was zone-refined and had a p-type resistivity of 150 ohm-cm. The major impurity was boron; the total impurity excluding the boron was reported by the supplier (Dow-Corning) to be typically less than 2 x 1013 atoms per cu cm. The crystals were examined by the Dash copper-decoration technique18'19—a method in which about 10" atoms per cu cm of copper are diffused at a temperature between 900" and 1000°C into silicon which is then quenched to room temperature. On quenching, the copper precipitates on crystalline defects which are then visible when viewed by transmission infrared microscopy. The photomicrographs shown were taken either of the infrared image tube screen or directly on infrared film. All sections prior to decorating were chemically polished and, for some sections, given a sirtlZ0 dislocation etch-pit examination. After decorating, the samples were mechanically polished. RESULTS A photomicrograph, taken in transmission of a decorated cross section, is shown in Fig. 1. The portion of the section shown is near the surface of the crystal. The entire cross section showed no dislocation etch pits after being given a Sirtl etch treatment. It is seen that the copper precipitated randomly. Each precipitate, as has been reported by others, was found to have a starlike structure.

Jan 1, 1965

By Leslie F. Tedsen, John E. Dorn, Alan E. Flanigan

It is necessary occasionally to use aluminum-alloy sheet where moderately elevated temperatures are encountered. Considerable attention has been directed toward determining the influence of "artificial aging" on the room-temperature properties of the precipitation-hardenable alloys, as testified by numerous company reports and by references I to 4. Investigations on the properties at elevated temperatures are few, however, and have not always covered the range of times and temperatures of greatest interest. The present investigation was instituted to overcome this deficiency. The work was done for the Office of Production Research and Development of the War Production Board, under the supervision of the War Metallurgy Committee, as a part of the "restricted" Project NRC-548. It has been released for publication by the Office of Production Research and Development. AS is well known, the high-strength aluminum alloys achieve their remarkable properties as a result of precipitation-hardening. In production they are subjected to a solution heat-treatment followed by quenching, to retain the supersaturated solid solution. The solution treatment is followed by "aging" (precipitation-hard- ening) either at room temperature or at a suitable elevated temperature. A considerable increase in tensile and compressive yield stresses results from precipitation at room temperature ("natural aging"). Through the elevated-temperature process ("artificial aging") it is possible to obtain values of yield stress considerably higher than those attainable by natural aging. The increase in yield stress is accompanied by a smaller gain in ultimate tensile stress and by a decrease in elongation. During the first stages of artificial aging the yield stress increases steadily until it reaches a maximum value. In this condition the material is said to be "fully aged." Further exposure results in "averaging," attended by a steady decrease in yield stress. In the production of the artificially aged materials, temperatures and times are selected to achieve full aging. The following important characteristics are associated with the process: 1. The higher the temperature, the more rapidly is the fully aged condition attained. :7

Jan 1, 1946

By Leslie F. Tedsen, Alan E. Flanigan, John E. Dorn

It is necessary occasionally to use aluminum-alloy sheet where moderately elevated temperatures are encountered. Considerable attention has been directed toward determining the influence of "artificial aging" on the room-temperature properties of the precipitation-hardenable alloys, as testified by numerous company reports and by references I to 4. Investigations on the properties at elevated temperatures are few, however, and have not always covered the range of times and temperatures of greatest interest. The present investigation was instituted to overcome this deficiency. The work was done for the Office of Production Research and Development of the War Production Board, under the supervision of the War Metallurgy Committee, as a part of the "restricted" Project NRC-548. It has been released for publication by the Office of Production Research and Development. AS is well known, the high-strength aluminum alloys achieve their remarkable properties as a result of precipitation-hardening. In production they are subjected to a solution heat-treatment followed by quenching, to retain the supersaturated solid solution. The solution treatment is followed by "aging" (precipitation-hard- ening) either at room temperature or at a suitable elevated temperature. A considerable increase in tensile and compressive yield stresses results from precipitation at room temperature ("natural aging"). Through the elevated-temperature process ("artificial aging") it is possible to obtain values of yield stress considerably higher than those attainable by natural aging. The increase in yield stress is accompanied by a smaller gain in ultimate tensile stress and by a decrease in elongation. During the first stages of artificial aging the yield stress increases steadily until it reaches a maximum value. In this condition the material is said to be "fully aged." Further exposure results in "averaging," attended by a steady decrease in yield stress. In the production of the artificially aged materials, temperatures and times are selected to achieve full aging. The following important characteristics are associated with the process: 1. The higher the temperature, the more rapidly is the fully aged condition attained. :7

Jan 1, 1946

By R. T. Pepper

DURING an investigation into the effect of heat-treatment on the creep properties of the magnesium alloy ZW1, (1 pct Zn, 0.6 pct Zr), the previously published methods of final polishing were found to be unsatisfactory. A new diamond-polishing technique has been developed to facilitate the study of fine precipitates in this and other magnesium alloys, and is described in this note. The sectioning and coarse grinding techniques are those of Fox and Hall,' and Hess and Cieorge.' Pre- liminary mechanical polishing is done with 6-µ, and 1-µ( grades of diamond compound on 'Microcloth' using a lubricant of 'Hyprez' oil. When the conventional technique is used with a 1/4- µ diamond wheel for the final polishing of magnesium alloys, scratching is likely to result from the abrasive action of the 'Microcloth' nap on the soft metal surface. This problem has been overcome by the use of a cream on the wheel in order to separate the specimen surface from the polishing cloth. To prepare this cream, a solution of 6-ml tri-ethanolamine in 75-ml water is stirred into 12.5 g stearic acid at a constant temperature of 80° to 90°C. The cream is allowed to cool, and is then 'whipped' to a smooth consistency with 100-ml 'Hyprez' oil. Before polishing, the diamond loaded 'Microcloth' is moistened with a few drops of 'Hyprez' oil, then a small amount of cream is worked into the nap. For the best results a wheel speed of 500 rpm should be used for polishing, and the specimen should be held by hand with a light pressure while being rotated in the opposite direction to the wheel. After polishing it is necessary to swab the specimen thoroughly in methylated spirits to remove residual cream and oil from the surface in order to avoid uneven etching and drying stains. Fig. 1 shows the surface finish obtained on a specimen by polishing on a 1/4- ° diamond wheel using the cream, and Figs. 2 and 3 the precipitate observed in ZW1 after polishing, and etching for two seconds in nitric acid 15 pct in ethylene glycol. This new diamond-polishing technique has made a valuable contribution to the programme of metal-lographic research on ZW1 and has become a routine laboratory practice for other low alloy content magnesium alloys.

Jan 1, 1961

By J. M. Tobin, L. H. Cadoff, L. M. Adelsberg

The reaction between liquid zirconium and graphite at temperatures above 2000 °C has been investigated. The reaction products were found to be carbon-saturated zirconium metal and ZrC which formed between the graphite and the metal. Parabolic growth behavior was observed for the ZrC Phase at all temperatures of this investigation. The parabolic growth constant at temperatures between 2000° and 2860°C was measured to be 1.83 exp 84,300/RT) sq cm per sec. The reaclion mechanism was proposed to be the rapid carbon saturation of the liquid metal and the formation of ZrC at the metal-carbide interface with diffusion of carbon through the ZrC, the "rate - determining step" of the reaction. The concentration-independent diffusion coefficient of carbon in ZrC, (DZrC), was expressed as 0.95 exp? 78,700/RT) sq cm per sec. This value mas calculated using the temperature-invariant ZrC phase fields proposed in the literature. The [ZrQiq)] — [ZYQiq) + ZrC] phase boundary over the temperature range 2000° to 2800°C was determined and the ZrC + C eutectic temperature was found to be 2890° ± 50°C. ThE Group IV and VB transition-metal refractory carbides are of interest because of their high melting points, high temperature strength properties, and relative inertness in certain corrosive environments. The present-day understanding of these materials, however, is limited by the general unavailability of accurate and reliable physical and chemical property data. This is due primarily to the difficulties associated with the preparation of suitable, high-density, high-purity carbide samples, and the achievement and control of uniform high-temperature environments. Accurate measurement of temperature is also an important factor limiting the reliability of reported data. The Zr-C reaction was selected for investigation because of the high melting point (>34000C) and favorable nuclear properties of the reaction product, ZrC. The direct reaction method afforded an opportunity to obtain kinetic data on the fully dense carbide. In this paper, layer-growth techniques were used to estimate the diffusivity of carbon in ZrC and to investigate the phase equilibria in the Zr-C system at temperatures above 2000°C. EXPERIMENTAL PROCEDURES AND DATA Crystal bar zirconium (99.9 pct Zr), purchased from the Nuclear Materials and Engineering Corp., and ZTA graphite (99.9+ pct) were used in this study. The analyses of the materials are listed in Table I. A schematic of the high-temperature carburization apparatus is shown in Fig. 1. The sample was a zirconium metal charge in a 1/2 -in.-ID graphite crucible which was capped with a tightly fitting graphite stern. The crucible and stem were designed to closely approximate black-body conditions. The graphite crucible was packed in lampblack (outgassed 1 hr at 2100°C) which provided insulation and thermal stability to the system. The inert atmosphere was maintained by a constant flow of high-purity argon or helium gas. The nozzle-diffuser section on the top flange was sufficient to prevent back-diffusion of air into the system. Chemical analysis of the carburized samples revealed oxygen and nitrogen concentrations of less than 44 and 20 ppm, respectively. The sample was heated by induction with a Westing-house 5 kw-450 kc power source. Temperature was measured with a Milletron two-color pyrometer which was sighted into the crucible by reflection from an overhead front surface mirror. Optical losses due to glass absorption and light reflection at air-glass interfaces were minimized by the employment of the dynamic-gas seal. It was found that no correction was required for the front surface reflector. The pyrometer was calibrated periodically against a U.S. Bureau of Standards tungsten ribbon secondary standard. Temperatures inside the crucible were also calibrated against the Zr-ZrC eutectic (1850°C)1 and the Nb-Nb2C eutectic (2335°C)2,3 temperatures and agreed to within ±10°C of these values. The temperature was controlled by manually adjusting the power input; variations of

Jan 1, 1967

V. R. GARFIAS,* Palo Alto, Cal. (written discussion?).-Regarding the statement of Mr. Ordoñez, on page 1007, concerning the synclinal curving of sedimentary beds caused by the extrusion of volcanic necks, that "this phenomenon might occur, but it is not fully proved in our fields," I beg to reply that the funnel and anticlinal-ring structure is actually associated with igneous intrusions in the Mexican oil fields, as we were able to ascertain by plotting an underground contour map and making a structural model of the oil-bearing beds of the Ebano field. E. DE GOLFER, New York, N. Y. (written discussion?).-The paper under discussion is not only of interest in connection with its subject but it is a contribution of considerable importance to our knowledge of the possible effect of igneous rocks upon the accumulation of petroleum in the Mexican fields.

Jan 10, 1918

By Oswald J. Heinrich

THE responsibility resting upon the owners and managers of mines where fire-damp is generated, renders it a matter of imperative duty that a full and correct statement of any explosion that occurs should be given to the public. But such a statement must be based on the testimony of impartial eye-witnesses or trained experts. Then a sad experience may result in the adoption of effective preventive measures. In the absence of any official and professional body of mining experts in the State of Virginia, the writer desires to submit to his professional brethren of the American Institute of Mining Engineers an account of an explosion which recently took place in a colliery under his management, and earnestly desires a thorough and impartial discussion on the facts submitted. Description and Plan of the Mine.-The "Grove" shaft is situated at the nearest point 825 feet from the last old workings upon the Midlothian property, south of the old Pump shaft works. (See Plate III.) The shaft was sunk by the former company, some thirty years ago, to the depth of 622 feet. An incline over 230 feet long, starting in a northwest direction at a depth of 105 feet above the shaft bottom, had been driven to explore the coal on the dip. A return of very small dimensions had been driven round the shaft on the south side, entering the upcast chamber. With the information obtained from the former company that a seam of coal about four feet thick, at a depth of 490 feet, had been found, and with the information obtained by the present proprietor, R. T. Burrows, of Albion, N. Y., by means of two boreholes on the dip west of the old shaft, in both of which workable seams of coal at various depths had been ascertained, the clearing out and thorough retimbering of this shaft were commenced in March, 1873. Borehole No. 1, at a depth of 477 1/2 feet from surface, revealed a seam of coal. This borehole was afterwards carried to a depth of 1140 feet to the granite, without finding any other seam of coal. Borehole No. 3, at a depth of 608 feet, revealed the first coal-seam, 142 feet thick; at 633 feet, the second, 12 feet thick; at 662 feet the third, 1 foot thick, and at 692 feet the fourth, 4 1/2 to 5 feet thick. The borehole was stopped at a depth of 715 1/2 feet.

Jan 1, 1877

By E. R. Parker, D. L. Martin

In a previous paper one of the authors observed that the rate of cooling from the anneal prior to testing greatly influenced the life of copper under sustained load at 200°C. Furnace-cooled bars of oxygen-free copper (with and without silver) had a life four to twenty-five times that of the water-quenched specimens. The addition of 0.054 per cent silver to the oxygen-free copper increased the life at a stress of 20,000 lb. per sq. in. from about 2 hr. to 50 hr. Fractures in these bars were intercrystalline. An explanation was advanced to account for the profound influence of cooling rate on the rupture properties at 200°C. The suggestion offered was that at the high annealing temperature the minor constituents are distributed at random. By water quenching, this condition is maintained at room temperature, whereas furnace cooling permits some segregation at the grain boundaries. The higher concentration of the minor constituents in the grain boundaries results in a. strengthening, so that a longer life at a given stress and .temperature results. Small amounts of cadmium or manganese have also been found to increase the life of copper at 200°C., and to a much greater extent than silver.2 The increase in the long-time strength of copper resulting from small additions of cadmium or silver appears to be related, indirectly at least, to the higher softening temperatures of such alloys. The elements, such as silver or cadmium, which greatly increase the rupture life of copper also cause large increases in the softening temperature. As little as 0.05 per cent of cadmium or silver is sufficient to raise the softening temperature more than 100°.3,4 The effects of cooling rate and of minor constituents on the rupture properties are of considerable fundamental as well as practical interest; therefore a more detailed study of their nature was conducted and is reported in this paper. Experimental Procedure Materials The materials studied in this investigation may conveniently be classified in two groups: one consisting of a wide variety of commercial coppers, and the other composed of special high-purity, laboratory-prepared coppers. The commercial materials were tested to determine whether or not the effect of cooling rate occurred with all coppers, whereas the high-purity coppers were investigated in order to establish a basis for evaluating the effect of minor constituents on the rupture properties. In Table I are given the analyses of the coppers tested. The samples I to 6 are commercial materials and were obtained for the most part from stock supplies.*

Jan 1, 1944

By D. L. Martin, E. R. Parker

In a previous paper one of the authors observed that the rate of cooling from the anneal prior to testing greatly influenced the life of copper under sustained load at 200°C. Furnace-cooled bars of oxygen-free copper (with and without silver) had a life four to twenty-five times that of the water-quenched specimens. The addition of 0.054 per cent silver to the oxygen-free copper increased the life at a stress of 20,000 lb. per sq. in. from about 2 hr. to 50 hr. Fractures in these bars were intercrystalline. An explanation was advanced to account for the profound influence of cooling rate on the rupture properties at 200°C. The suggestion offered was that at the high annealing temperature the minor constituents are distributed at random. By water quenching, this condition is maintained at room temperature, whereas furnace cooling permits some segregation at the grain boundaries. The higher concentration of the minor constituents in the grain boundaries results in a. strengthening, so that a longer life at a given stress and .temperature results. Small amounts of cadmium or manganese have also been found to increase the life of copper at 200°C., and to a much greater extent than silver.2 The increase in the long-time strength of copper resulting from small additions of cadmium or silver appears to be related, indirectly at least, to the higher softening temperatures of such alloys. The elements, such as silver or cadmium, which greatly increase the rupture life of copper also cause large increases in the softening temperature. As little as 0.05 per cent of cadmium or silver is sufficient to raise the softening temperature more than 100°.3,4 The effects of cooling rate and of minor constituents on the rupture properties are of considerable fundamental as well as practical interest; therefore a more detailed study of their nature was conducted and is reported in this paper. Experimental Procedure Materials The materials studied in this investigation may conveniently be classified in two groups: one consisting of a wide variety of commercial coppers, and the other composed of special high-purity, laboratory-prepared coppers. The commercial materials were tested to determine whether or not the effect of cooling rate occurred with all coppers, whereas the high-purity coppers were investigated in order to establish a basis for evaluating the effect of minor constituents on the rupture properties. In Table I are given the analyses of the coppers tested. The samples I to 6 are commercial materials and were obtained for the most part from stock supplies.*

Jan 1, 1944

By D. L. Martin, E. R. Parker

IN a previous paper, one of the authors observed that the rate of cooling from the anneal prior to testing greatly influenced the life of copper under sustained load at 200°C. Furnace-cooled bars of oxygen-free copper (with, and without silver) had a life four to twenty-five times that of the water-quenched specimens. The addition of 0.054 per cent silver to the oxygen-free copper increased the life at a stress of 20,000 lb. per sq. in. from about 2 hr. to 50 hr. Fractures in these bars were intercrystalline. An explanation was advanced to account for the profound influence of cooling rate on the rupture properties at 200°C. The suggestion offered was that at the high annealing temperature the minor constituents are distributed at random. By water quenching, this condition is maintained at room temperature, whereas furnace cooling permits some segregation at the grain boundaries. The higher concentration of the minor constituents in the grain boundaries results in a strengthening, so that a longer life at a given stress and temperature results. Small amounts of cadmium or manganese have also been found to increase the life of copper at 200°C., and to a much greater extent than silver .2 The increase in the long-time strength of copper resulting from small additions of cadmium or silver appears to be related, indirectly at least, to the higher softening temperatures of such alloys. The elements, such as silver or cadmium, which greatly increase the rupture life of copper also cause large increases in the softening temperature. As little as 0.05 per cent of cadmium or silver is sufficient to raise the softening temperature more than 100°.3,4 The effects of cooling rate and of minor constituents on the rupture properties are of considerable fundamental as well as practical interest; therefore a more detailed study of their nature was conducted and is reported in this paper. EXPERIMENTAL PROCEDURE Materials The materials studied in this investigation may conveniently be classified in two groups: one consisting of a wide variety of commercial coppers, and the other composed of special high-purity, laboratory-prepared coppers. The commercial materials were tested to determine whether or not the effect of cooling rate occurred with all coppers, whereas the high-purity coppers were investigated in order to establish a basis for evaluating the effect of minor constituents on the rupture properties. In Table I are given the analyses of the coppers tested. The samples I to 6 are commercial materials and were obtained for the most part from stock supplies.*

Jan 1, 1943

By Strathmore R. B. Cooke

On the basis of experiments conducted on quartz using a bubble pick-up method, it was shown in an earlier paper1 that this mineral will preferentially adsorb hydrogen, calcium, or sodium ions, depending on the relative concentrations of those ions in the solution in which the quartz is immersed. For quartz particles ranging in size from 0.2 to 1 mm, it was demonstrated that the concentration of calcium in solution (assumed present as ions) necessary to completely activate quartz for flotation is given by the expression: Ca++ = [H+] X 106 + [Na+] X 10-3 In this expression, ionic concentrations are in mols per liter. It was further shown that the pick-up method is apparently more sensitive to changes in reagent concentration than the standard captive-bubble method, and that induction times are apparently much reduced. Since completing these earlier tests, a new type of cell has been constructed; this is shown in Fig 1 and 2. In Fig 1, A is a ground joint, B is a central tube reaching to within a few millimeters of the bottom of the cell, and C is a stopper which may be removed for reagent addition, and serves the further purpose of excluding carbon dioxide from the air during the test. The entire cell is constructed of Pyrex glass, and does not give the trouble experienced with the earlier cell, in which activating ions were released from the glass at high pH values. The only critical factor in the construction of the cell is the clearance between the central tube and the bottom of the cell. This clearance should be sufficiently small that the bubble can be pressed directly on the mineral grains lying on the bottom of the cell. In the pick-up tests to be described in this paper, the reagents used were all of C. P. grade, except the sodium oleate, which was Merck's "neutral powder." The quartz employed was water-clear vein quartz, sized on screens, cleaned with both hydrochloric acid and sodium hydroxide, and given a thorough final washing with distilled water. Experimental procedures were the same as described in the earlier paper. EFFECT OF SIZE OF QUARTZ ON PICK-UP To ascertain the effect of particle size on the adsorption of calcium ions, the quartz was sized from minus 14 plus 20 mesh through the intervening screen sizes to minus 270 mesh plus 400 mesh. Each size was thoroughly cleaned, and then tested in the cell at different calcium chloride and sodium hydroxide concentrations, and at a constant sodium oleate concentration of 20 mg per liter. All particles, within the size range given, exhibited complete pick-up within the curve expressed by the equation above. This presumably means, when the conditions imposed by the equation are satisfied, that this maximum is independent of particle size. However, it was found that the range through which partial particle pick-up occurred progressively broadened as particle size decreased. This is shown in Fig 3, in which curves B, C, and D show the limits at which pick-up just commences (as the pH is increased) for particles of minus 14 plus 28 mesh, minus 65 plus 100 mesh, and minus 270 plus 400 mesh size, respectively. These results indicate that for satisfactory activation, at any given pH, a lower calcium ion concentration is required for fine particles than for coarse particles. EFFECT OF HIGH ALKALINITY ON PICK-UP At calcium concentrations of between 1 and 10 mg per liter, and at high alka-linities, it was noticed that pick-up ceased as soon as calcium hydroxide commenced to precipitate. This effect was investigated at other calcium concentrations, with the same results. Solutions of calcium chloride, containing 105, 104, l03, and l02 mg of calcium per liter were made alkaline with sodium hydroxide until calcium hydroxide just started to precipitate, according to the following equation: CaCl² + NaOH -+ Ca(OH)2 + 2NaCl The beginning of precipitation was taken as that point at which either a faint opalescence appeared in the solution, or a Tyndall cone became ap-

Jan 1, 1950

By Charles H. Doolittle, Royal P. Jarvis

The following notes are contributed, not with the idea of offering a complete history of the development of this very important process as applied to the Leadville district, but with the hope that the practice, as it was carried out in the Bi-Metallic Smelter, may still be of interest to others. The Bi-Metallic Smelter, at Leadville, Colo., was the first to make a commercial success of the process described in the following pages, which consisted essentially of smelting raw silver- and copper-bearing sulphide ores in blast-furnaces to form a matte, which was generally re-smelted with siliceous ores for a second high-grade matte. Robert Sticht, in his excellent monograph on the subject,' has outlined briefly the plant belonging to this company. He says, in effect: The Boulder, Mont., enterprise set the example for others with whom the patentee (W. L. Austin) had been negotiating, and the old La Plata lead-smelter at Leadville, Colo., was fashioned into a crude, temporary experimental plant for the Bi-Metallic Company, and the feasibility of the process demonstrated by a trial run. Subsequently, the plant was considerably improved, and, being supplied with very favorable ores, continued to run without interruption from August, 1892, to June, 1893. In September, 1803, smelting was resumed in a completely remodeled establishment, some $200,000 having been expended upon the new work. Thus, aside from the Montana experiments, which, under the direction of W. L. Austin, began as early as 1885 at Toston, and continued with indifferent success for six or seven years, the Bi-Metallic plant at Leadville may be said to have

Jan 1, 1911

By C. M. Schwartz, J. R. Bridge, D. A. Vaughan

THERMAL expansion coefficients of a uranium were originally reported' on the basis of X-ray diffraction measurement of lattice constants at 25°, 300°, and 650°C. These data have been reproduced by Katz and Rabinowitch.' CuK radiation had been used in this work, with consequent crowding of the patterns. Considerable overlap of the back-reflection lines was observed as the temperature was raised. Subsequent reexamination of the data led to the conclusion that errors had resulted from failure to obtain unequivocal indexing of the high angle reflections at elevated temperatures. The measurements have been repeated, using FeK radiation, which provided sufficient dispersion to assure proper indexing of the reflections, at each temperature level. The unit cell dimensions were re-determined at ten temperatures, from 25" to 650°C. Schuch and Laquer easured the macroscopic contraction from room temperature down to —253°C, and reported a negative value from —210" to —253°C; they suggested the possibility of the occurrence of a phase change. In the present work, the lattice constants of uranium have been measured down to —253°C, to test this hypothesis. Filings were prepared from a single piece of pure uranium bar stock. They were carefully cleaned with a magnet and pickled in nitric acid to remove traces of iron from the file. They were then annealed at 600°C in a sealed evacuated silica tube. The annealed filings were pickled in strong nitric acid to remove any oxide layer, washed in water and alcohol, quickly dried, and sealed in evacuated thin-walled silica capillary tubes. If properly sealed, the sample could be heated to the a-ß transforination temperature without significant buildup of the diffraction pattern of oxide. The high temperature X-ray diffraction camera was modified from the design of Hume-Rothery and Reynolds.' The thermocouple used to record the specimen temperature was calibrated from lattice-constant measurements of a standard silver specimen, using the Hume-Rothery and Reynolds values for silver over the temperature range from 25" to 700°C. Temperatures were reproducible to 210°C. Temperatures to —210°C were attained by passing precooled gas over the sample. The gas from the cooling train was directed over the sample capillary tube and thermocouple by means of a chimney of 1-mil polystyrene. The 36-gage Cu-constantan thermocouple had been calibrated by

Jan 1, 1957

Aaby, Alton O , (S'47) Univ of Minnesota, Mimeapolis, Minn Aaby, Waldo S , (S?48) Univ of Minnesota, Minneapolis Minn Aalde, Kaare, (S'48) Univ of Nevada, Reno, Nev Aaring, Floyd D , (S'48) Univ of Oklahoma, Nor man, Oka Aaronson, Hubert I , (S'47) Carnegie Inst of Technology, Pittsburgh, Pa Abbott, Peyton Osborn, (S'46) 1502 Westover, Austin 21, Texas Abel, Malcolm D , (S'47) Univ of Texas, Austin, Texas Aberg, Richard S , (S'47) Univ of Minnesota, Minneipolis, Minn Abrahamson, Guy C , (S'43) 420 W Dennis St , Wilmington, Calif Abrahao, Benjamin, (S'46) Escola Politeenica da Unnersidade, de Sin Piulo, Braizil Achter, Meyer R , (S'46) Carnegie Inst of Tech , Pittsburgh, Pa

Jan 1, 1952

By W. S. Stahmann, F. W. Bowdish

Previously published experimental data showing that both collectable and non-collectable sulfide films may be formed on chrysocolla were analysed, and chemical mechanisms were proposed for the formation of the films. A special technique was developed by which the quantity of sulfur adsorbed was determined for samples sulfidized under different conditions of pH and soluble sulfide concentration. The data on sulfur adsorption were used together with the expression for the equilibrium constant for the proposed reaction to indicate the validity of the chemical mechanism theory. A recent paper 1 about contact angle studies on chrysocolla reported the effects of pH value and sodium sulfide concentration during sulfidization upon the character of the surfaces produced. In each experiment the surface of a specimen of chrysocolla was prepared by grinding it with fine abrasive and washing it in tap water. The specimen was then placed in the sulfidizing solution for 10 min, rinsed in tap water, treated for 15 min in a solution containing 30 mg of potassium amyl xanthate per liter, rinsed in distilled water, and tested for air adhesion in a contact angle apparatus. The results, when plotted as in Fig. 1, showed an island representing conditions giving air adherent or collectable surfaces surrounded by conditions giving non-collectable surfaces. Particular interest may be attached to the region of non-collectability to the right of and above the island in Fig. 1, and to the boundry curve separating these two regions. It is apparent that at any pH from 4.0 to 6.0, where a collectable surface may be produced, a sufficient increase in the sulfide concentration results in a non-collectable surface. Thus it appears that too much soluble sulfide has a depressing effect upon the mineral, just as it has in sulfide flotation. This paper presents some speculations regarding the chemical mechanisms by which the collectable and non-collectable sulfide films may be formed and reports on a physical-chemical study intended to support these speculations. THEORETICAL CONSIDERATIONS The experimental results presented in the previous paper were analysed in several ways in an attempt to understand better the chemical mechanisms involved. For several points on the boundary to the right of the region of contact in Fig. 1, molar concentrations of H+, OH-, HS-, and S= ions, as well as various ion concentration products, were calculated. Following the reasoning of Wark and Cox, 2,3 no single kind of ions may be credited with causing depression of the surface because none of them have a constant con-

Jan 1, 1968