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By W. R. Bendy

GRINDING is a large and costly part of Portland cement manufacture. Prior to clinkering in the rotary kiln, raw materials are ground to a fineness of 80 to 90 pct passing 200 mesh. Then, after burning and cooling, the resulting clinker is ground to about 92 pct passing 325 mesh. In the cement industry the most favored method of grinding has always been by impact and attrition of a ball charge in a rotating mill. Other types of mills, in which materials are ground between die rings and rollers, or between die rings and large balls, are sometimes used for single-stage grinding and often for preliminary grinding followed by grinding in ball-type mills. Their efficiency is usually high, but maintenance and repair costs are high also, and the ball-type mill continues to be the most widely used. Together with 4 pct gypsum to retard setting time, the kiln run clinker—consisting of hard, semi-fused lumps that may have been crushed to — 1/2 in.—is ground to a Blaine surface area of 3000 sq cm per gram and about 92 pct passing 325 mesh. Approximately 32 kw-hr per ton, or 6 kw-hr per 376-1b barrel, are consumed in the grinding mills alone, not counting auxiliaries. Open Circuit Clinker Grinding: Many early clinker grinding plants employed two-stage, open circuit grinding. Comparatively short mills of large diameter, loaded with balls 4 in. and smaller, first reduced the clinker to 95 pct passing 14 mesh. Tube mills of smaller diameter and greater length, loaded with balls 11/4 in. and smaller, carried out the fine grinding operation. An early development was to assemble two or more stages of grinding in a single mill having two, three, or four compartments separated by division heads. There were difficulties in balancing the compartments, but compartment mills were popular in the 1920's because the layout was simple and there were no elevators and conveyors. Oversize Particles: Open circuit mills, whether separate ball and tube mills or compartment mills, always encountered the problem of tramp oversize in the product. A small percentage of clinker survived passage through the first grinding stage as particles—perhaps 1/16 in. diam—that were too large for the smaller balls in the following stages to reduce to —200 mesh. When the feed rate was lowered to reduce tramp oversize, there were serious losses in grinding efficiency. Many ingenious designs were perfected to incorporate perforated screen plates or wire mesh screens in the ball mills or in the first compartments of compartment mills. Their purpose was to prevent mate: rial passing out of the first stage until it was small

Jan 1, 1958

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

THE external appearance of a crystal which has undergone plastic flow suggests that adjacent blocks of the crystal have glided bodily past one another along the slip planes. However, the great discrepancy between the shear stresses calculated to effect such a movement and those actually observed has for many years stimulated searches for more satisfactory interpretations of the slip process. Appreciable success in these efforts has been realized by assuming the presence in the crystal of various sorts of imperfections and by considering the consequences of the presence of these flaws when stress is externally applied, The theory that has received the most attention recently-that of dislocations-postulates the occurrence of small, mobile imperfections or dislocations which move through the crystal along the slip direction, each dislocation being attended by a local shear displacement of one interatomic distance. Thus only that portion of the crystal through which the dislocation has passed may be said to have slipped, Since each dislocation produces a displacement of only one interatomic distance, an avalanche or train of many dislocations would be necessary to account for the observed displacements of several hundred or thousand interatomic distances. The salient point of the theory of dislocations is the concept that a slip band does not suddenly appear in its entirety. On the contrary, it grows progressively across the slip plane as the individual dislocations successively appear and advance in a train through the crystal. However, the concept of growth is not intrinsic only to the theory of dislocations, since atomistic mechanisms other than that postulated by the dislocation theory can quite probably also describe the growth of a slip band. For instance, a slip band might resemble a disc-like interface that appeared and then grew continuously from a small size, producing a displacement that increased with the size of the disc, Whatever the precise mechanism, the concept of growth is in itself consistent both with -the observed low values of critical shear stress and with the experimental observation that slip bands. frequently do not traverse the entire crystal. The likelihood that slip bands grow implies that they must first be nucleated and that the initiation of slip can therefore be analyzed in terms of the general concepts of nucleation. Indeed, this suggestion was advanced1 several years ago, but the matter does not appear to have been further pursued. Recent advances in the theory of nucleations2,3,4 have encouraged such a treatment of the slip process. As will presently be demonstrated, this approach to the problem not only accounts successfully for the incubation periods that have been observed5,6 to precede slip but also predicts certain transient effects in the deformation process, The existence of these transients apparently has not hitherto

Jan 1, 1948

By C. H. Mathewson, H. l. Burghoff

The study of the creep of metals under conditions of prolonged loading has received the attention of many investigators for several years and almost innumerable papers have been published on the various aspects of the subject. As it appeared that much could still be learned from a study of single crystals, the present work was carried out to study the effects of temperature and conditions of loading upon the properties and deformation in tension of single crystals of alpha brass containing about 70 per cent copper and go per cent zinc. In particular, it was hoped to obtain information from tests below and above the recrys-tallization temperature of the material, so that properties such as elastic limit, yield point or critical stress, and manner of deformation might be compared for tensile tests at an ordinary loading rate and for prolonged loading. Accordingly, short-time tensile tests and creep tests were made at room temperature, 300°, 500° and 700°F. The two latter temperatures are above the lowest possible recrystallization temperature of polycrys-talline 70-30 brass. Previous Work Clarke and White1 have made creep tests of some copper-zinc alloys, including 70-30 brass, and copper-zinc-tin alloys at temperatures both below and above the recrystallization temperature of the materials considered. Hanson and Wheeler2 have studied the flow and fracture of single crystals of aluminum for short-time and prolonged tensile loading over a range of temperature extending from room temperature to 400°F., their experiments being made without consideration of the orientations of the test specimens. Extensive creep and fracture tests on single crystals of lead at room temperature have been made by Betty3 and by Baker, Betty and Moore." Results of the last-named investigation were published while the present work was in progress. Miller5 examined the elastic limit of zinc single crystals at and above room temperature by means of creep tests, while Miller and Milligan6 reported the results of tests designed to show the influence of temperature on elastic limit of single crystals of aluminum, silver and zinc. The behavior of iron crystals under static tensile loading at room temperature was reported by Gensamer and Meh17 while the present investigation was in progress. Their specimens exhibited a well-defined yield point, below which no appreciable creep could be detected. The manner of yielding proved interesting, as the shape of the creep-time curve for the iron crystals differed from the common type of crcep curves. Elongation did not begin immediately, or at least was initially very slow. The rate of elongation then increased continuously and finally decreased to zero. This S-shaped type of elongation-time

Jan 1, 1941

By H. l. Burghoff, C. H. Mathewson

The study of the creep of metals under conditions of prolonged loading has received the attention of many investigators for several years and almost innumerable papers have been published on the various aspects of the subject. As it appeared that much could still be learned from a study of single crystals, the present work was carried out to study the effects of temperature and conditions of loading upon the properties and deformation in tension of single crystals of alpha brass containing about 70 per cent copper and go per cent zinc. In particular, it was hoped to obtain information from tests below and above the recrys-tallization temperature of the material, so that properties such as elastic limit, yield point or critical stress, and manner of deformation might be compared for tensile tests at an ordinary loading rate and for prolonged loading. Accordingly, short-time tensile tests and creep tests were made at room temperature, 300°, 500° and 700°F. The two latter temperatures are above the lowest possible recrystallization temperature of polycrys-talline 70-30 brass. Previous Work Clarke and White1 have made creep tests of some copper-zinc alloys, including 70-30 brass, and copper-zinc-tin alloys at temperatures both below and above the recrystallization temperature of the materials considered. Hanson and Wheeler2 have studied the flow and fracture of single crystals of aluminum for short-time and prolonged tensile loading over a range of temperature extending from room temperature to 400°F., their experiments being made without consideration of the orientations of the test specimens. Extensive creep and fracture tests on single crystals of lead at room temperature have been made by Betty3 and by Baker, Betty and Moore." Results of the last-named investigation were published while the present work was in progress. Miller5 examined the elastic limit of zinc single crystals at and above room temperature by means of creep tests, while Miller and Milligan6 reported the results of tests designed to show the influence of temperature on elastic limit of single crystals of aluminum, silver and zinc. The behavior of iron crystals under static tensile loading at room temperature was reported by Gensamer and Meh17 while the present investigation was in progress. Their specimens exhibited a well-defined yield point, below which no appreciable creep could be detected. The manner of yielding proved interesting, as the shape of the creep-time curve for the iron crystals differed from the common type of crcep curves. Elongation did not begin immediately, or at least was initially very slow. The rate of elongation then increased continuously and finally decreased to zero. This S-shaped type of elongation-time

Jan 1, 1941

By W. T. Isbell, Carleton C. Long

Zinc recovery from lead blast-furnace slags has heretofore been an indirect process, involving, first, the fuming off and collecting of an impure zinc oxide, and second, the reduction of the zinc portion of this oxide to metal either by electrolytic or pyrolytic means. (In a variation of this process, blue powder is the intermediate product rather than zinc oxide fume.) In 1940, W. T. Isbell proposed that molten slag from the lead blast furnace or stock-pile slag melted down in a blast or cupola-type furnace be charged directly into an airtight container (i.e., furnace) provided with means to heat further the slag by passage of electric current and means to introduce the carbon (coke) necessary to reduce the ZnO constituent of the slag to zinc as a zinc vapor and CO. He also proposed that the zinc vapors so obtained be condensed in a Weaton-Najariant internal condenser directly connected to the proposed furnace. It was thought that the Weaton-Najarian condenser could liquefy zinc vapor from lean mixtures of vapor and noncondensable gases. Such condensers have been in commercial use! since 1936 at Josephtown smelter, where the source of zinc vapor is a column of coke and zinc-bearing sinter electrically heated (charge resistor). Condenser output when supplied with vapor-gas mixtures containing approximately 45 per cent zinc and 55 per cent noncondensable gases, varies from 18 to 30 tons of slab zinc per day per condenser, depending upon the heat-transfer area (length) of the condenser and the volume of vapor (furnace size) fed to it. Lead-smelting operations at the St. Joseph Lead Company's plant at Hercu-laneum, Mo., produce a slag containing 12 to 16 per cent zinc. For several years this slag has been stock-piled with the object of recovering the zinc values if and when a commercial method was invented. Evaluation of the possibilities of the proposed method was made by pilot-plant operation at Josephtown. The first plant, designed in 1940 and operated in early 1941, consisted of a single-phase, two-electrode furnace. The evolved vapors were burned. Electrical characteiistics of the molten slag, power requirements, coke requirements, and extent of zinc elimination indicated the feasibility of the proposed method. In the latter part of 1941 a second pilot furnace was constructed, to which "was attached a small (6 ft. long) Weaton-Najarian condenser in order to develop an over-all picture of zinc-in-slag to zinc-in-slabs. This furnace was operated in the early part of 1942 and yielded such promising results that a decision was made to design- and construct a commercial furnace. Feed for the pilot-plant furnaces was granulated slag. A suitable deduction (300 to 350 kw-hr. per ton slag) was calculated in estimating power require-

Jan 1, 1944

By K. S. Krishnam, A. G. Guy

VOLUME 6 of the Transactions of the Baikov Institute of Metallurgy, Moscow, is devoted to the subject of "the experimental and theoretical study of the physical characteristics of dilute solid solutions,11 and summarizes work that has been done largely in the years 1958-9. In view of the attention that Soviet investigators have given to this subject, it seemed useful to carry out an independent experimental investigation in an effort to judge the scientific basis and practical significance of this field of study. The present note is a preliminary report of this investigation. The first property studied by the Soviet group was X-ray spectra of solid-solution alloys.' An anomaly observed at low concentrations (--0.05 at. pct) of the alloying element led to the theory that each impurity atom in a transition-metal base alloy is the center of a "block" of affected atoms with a radius of about 10"7 cm. This theory was further developed in a later paper.2 By this time similar anomalies had been found in diffusion coefficients3 and in thermal expansion.4 The entire development up to 1959 was reviewed in a comprehensive paper, and further theoretical ideas were also published at this time. Finally, the volume mentioned above was published in 19607 giving new experimental data on anomalies in optical properties and Hall constant, and a new theoretical treatment also appeared.' Although western scientists have done both theoretical work, summarized recently by Friedel,9 and considerable experimental work on dilute solid solutions, there is little support for the marked anomalies reported in the Soviet papers. Of the physical properties studied by the Soviet investigators, thermal expansion was chosen for the present investigation because of the relative ease of obtaining the necessary precision of measurement. A Leitz dilatometer was used for this purpose, and a special technique involving interchanging of the two specimens being compared permitted a precision of 0.05 x X in average thermal expansion over the range 27° to 600°C. The specimens were heated and cooled in vacuum or in a protective atmosphere at a rate of 50 °C per hr. Ferrovac E iron was used as the comparison specimen and in every case had a coefficient of expansion higher than (or equal to) that of the alloy. Since unintentional impurities are an important factor in studies of dilute alloys, special attention was given to the purity of the iron and the alloys used. The alloys were the same of those used by Abrahamson10 and by Michalak," and their preparation is described in these references. Chemical analyses of the Ferrovac E iron and of typical Fe-W and Fe-Mo alloys are given in Table I. The purity of the iron and alloys is undoubtedly higher than in the

Jan 1, 1962

By C. M. Romanowitz, H. A. Sawin

PLACER dredging as we know it today, especially gold dredging, is an industry about 40 years old, dating from the beginning of this century, when a few mining men in California saw the possibilities in adapting earlier dredging methods to California placer fields in and immediately adjacent to streams. At first it was thought that dredges must be operated in existing stream beds, but experience soon pointed the way to dredging alluvial deposits of old stream beds, operating on landlocked dredging ponds. Within the first five or six years of modern dredging, experience was gained so rapidly that dredges to dig 60 ft. below water level were designed and built. This depth was believed by many operators to be the maximum at which successful dredging could be carried on. Alluvial deposits of gold, suitable for dredging, were readily handled by equipment available and developed early in the industry's history. Much of the gravel was easily dug and if deposits were cemented, contained large boulders, or for some other reason could not be handled by a dredge, the ground was abandoned in favor of other deposits that could be handled easily. Many failures, adversely affecting the dredging industry, resulted from attempts at that time to extend the scope of placer dredging with equipment not suited to the formation being dredged. Dredging ground suited to early equipment was exhausted eventually, but many supposedly undredgeable alluvial fields containing gold in commercial quantities were found and became known to dredgemen. Improved equipment was needed to work deposits known to exist at great depths or associated with unusual obstructions. Operating companies looked to dredge manufacturers and metallurgists, particularly manganese-steel foundries, for improved designs and materials. Experience developed in California has spread throughout the world, and dredges of improved types have been adapted to the mining of platinum and tin as well as gold. Space will not permit a description of all the improvements in dredging since the early days, but a few of the recent developments are worthy of note, because they make possible the dredging of placer deposits of great depth, those having hard, irregular bedrock or containing large boulders in great quantities, and compacted or cemented gravel deposits. DEEP DREDGING At Hammonton, Calif., Yuba Consolidated Gold Fields has, within the past two years, built its dredge No. 20. The company has operated continuously in that field since 1904, digging successively at maximum depths of 60 ft., 80 ft., 112 ft., and now 124 ft. below water level. The first dredges were equipped with buckets of 6 and 7 1/2-cu. ft. capacity; six dredges operating in the field today have 18-cu. ft. buckets, digging now 65 to 124 ft. below water level. Some ground near Hammonton has been dug for the third time, owing to the devel-

Jan 1, 1941

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

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

Jan 1, 1949

By H. E. Hostetter

GROSSMANN'S method1 for calculating the hardenability of steel from the composition and grain size has gained wide acceptance, and when properly used, has been well proved in practical application, both for estimating the hardenability of known compositions and for selecting compositions to meet known hardenability requirements. The Grossmann method uses as the criterion of hardenability the "ideal critical diameter," DI, which is the size round that will just harden to a structure of 50 per cent martensite at the center when given the theoretically fastest quench, or "ideal quench." The DI can be related to actual quenching practice if the severity of quench is known; or the DI can be correlated with hardenability as determined by the Jominy end-quench method.2 The effect on hardenability of each element present in a steel can be represented by a multiplying factor, the value of which depends on the amount of the element present and the degree of effectiveness of the particular element. (The value of the factor for a given carbon content varies with the grain size.) When the factors for all elements present in a steel have been determined from charts, they are multiplied, and the resultant product is the D, of the steel. The validity of Grossmann's scheme of multiplying factors has been confirmed in a number of other investigations.3 -6 It can be appreciated that a certain desired level of hardenability can be obtained by adding chromium, molybdenum, nickel and vanadium to a base composition containing carbon, manganese, silicon and the usual impurities. Many of the ranges of hardenability used commercially can be obtained by any of the foregoing alloying elements used singly in the base composition. The same hardenability levels also can be obtained through use of any of a great number of multiple element combinations of these alloying elements. In this report a method will be presented for determining what one combination is the most efficient (based on hardenability and cost of added alloy) for a given level of hardenability. It should not be assumed from the emphasis given to hardenability, that hardenability is the only criterion for the selection of an alloy composition. Such properties as the hot-working characteristics, machinability, carburizing characteristics, amount of distortion during quenching and the retention of austenite may be considerations of importance in many applications. However, hardenability is one of the most important properties of an alloy steel and one that must be considered in almost all cases involving heat-treatment by quenching. Therefore, a method for determining the lowest-cost alloy combination should be of considerable value. DETERMINATION OF MOST EFFICIENT COMBINATIONS For comparing the alloying elements on standards of cost and hardenability, it

Jan 1, 1945

By M. J. Saarivirta, P. P. Taubenbla

This paper presents some high-temperature properties of copper-zirconium conductor alloy compared to copper-chromium alloy. Definite superiority of the copper -zirconium alloy over the copper-chromium alloy at high temperatures is shown. RECENT investigations have shown that cold-worked copper-zirconium alloy possesses good room-temperature strength, ductility, and conductivity and maintains most of its strength at temperatures up to 450°C (840°F). As a result, this alloy is now used for many applications, such as commutator segments, resistant welding wheels and tips, rectifier bases, electrical contacts, and so forth. Early investigations1-3 have shown that the maximum solid solubility of zirconium in copper is close to 0.15 pct and the alloy containing Cu-0.10-0.15 pct Zr exhibits the optimum mechanical and physical properties. Results2 have also shown that the alloy has better elevated temperature strength and ductility than copper-chromium and copper-silver alloys. The present investigation was undertaken to learn more about the elevated temperature properties of copper-zirconium alloy and to compare these properties with those of the copper-chromium alloy. WORK PROCEDURE The commercial copper-zirconium alloy, Amzirc was selected for this investigation. Because this alloy is composed of oxygen-free high-conductivity copper and 0.10-0.15 pct Zr, it was believed that possible disturbance from impurities would thus be negligible. Copper-chromium alloys used in this investigation contained 0.40 and 0.70 pct Cr and balance copper. The Cu-0.40 pct Cr alloy was a commercial brand, whereas the Cu-0.70 pct Cr alloy was made from OFHC copper and Cu-5 pct Cr master alloy. It was made in a graphite crucible under argon gas cover and cast. In the preparation of specimens, all three alloys were treated to give the optimum properties; thus the Cu-0.15 pct Zr alloy was solution annealed at different temperatures to determine the desirable solution annealing temperature. It was then cold worked and aged at 375" to 400°C (705" to 750" F). A solution annealing temperature of 1000°C (1830°F) was selected for the copper-chromium alloys because this temperature is widely used in commercial practice. The same alloy was aged at 450°C (840°F) after solution annealing and cold working. It was found that the maximum precipitation hardening of the copper-chromium alloy occurred at this temperature. When aged after solution annealing, the aging temperature was 500°C (930"F) for both alloys. The following properties were determined: 1) Tensile properties as a function of temperature. 2) Effect of solution annealing temperature on high-temperature tensile properties. 3) Stress to rupture strength at 350° and 400°C (660"to750°F). 4) Impact strength. 5) Electrical conductivity and resistivity as function of temperature. 6) Thermal expansion.

Jan 1, 1961

By E. I. Larsen

Powder metallurgy has been described as being "as old as the pyramids and yet as new as the latest bomber." While this may be true literally, it has been only in the last Io or 1 5 years that widespread use has been made of this method of fabricating various articles One of the first items fabricated by powder metallurgical methods on a commercial scale was electrical contacts, which were fabricated from metal powders as early as 1920. The reason why these contacts have been made for so many years by powder metallurgy is because the compositions of most of these materials arc such that they could not be made by the conventional methods of melting, casting, rolling, drawing, etc. Classes of Contacts In general, electrical contacts fabricated from metal powders fall into two classes, both from the point of view of the method of fabrication and the components that make up the chemical composition. One class is composed of silver or copper and a refractory metal such as tungsten, molybdenum, or compounds thereof such as carbides. The second class contains a predominant amount of silver and a semi-refractory material such as cadmium oxide, nickel, cobalt, or graphite. Electrical contacts of the first class have been developed primarily as facing materials for heavy-duty circuit-interrupting devices. This class of material unites the high melting point, high boiling point, great resistance to electrical erosion, and the refractory characteristics of molybdenum, tungsten, or their carbides with the high thermal and electrical conductivities and low contact resistance properties of silver or copper. The second class of material is used for lighter duty or specialized applications such as heavy-duty, direct-current aircraft relays. Varieties Electrical contacts fabricated from metal powders are made in a wide variety of compositions, shapes, and sizes. In general, the sizes of electrical contacts fabricated from powders vary from contacts weighing approximately 0.001 oz. up to those weighing 3 to 4 Ib., the contacting face being as small as 0.001 sq. in. up to approximately 6 sq. in. in area. The shapes consist of: sound or rectangular buttons, some of which have radii or bevels on the contacting faces; rings, cups, rectangular bars, the contact face of which may have a radius across the width and/or at one end; and form-pressed pieces of a wide variety such as angles, both acute and obtuse, irregular shapes comprising a radius blended into a flat, which in turn may have steps. The size or shape of the contact is dictated principally by the mechanical design of the manufacturer, who in turn may have problems to be met such as: (I) size, weight, or space limitations; (2) electrical conditions such as blowout coils arc chutes, baffies, gas passages.

Jan 1, 1945

By Harold Vagtborg

Equilibrium vaporization ratios were obtained for light hydrocarbons, nitrogen, carbon dioxide, and hydrogen sulfide in a reservoir fluid containing 35 mole per cent hydrogen sulfide. The data cover the range from 700 to 2500 psia at 154°F. The results of this study are compared with results obtained by other investigators on systems containing less hydrogen sulfide. When large amounts of hydrogen sulfide are present, the equilibrium vaporization ratios for ethane and heavier hydrocarbons are greater than the ratios for systems containing little or no hydrogen sulfide. Large amounts of hydrogen sulfide have the reverse effect on the ratios for methane. Routine PVT studies were performed on the reservoir fluid including flash and differential liberations of the dissolved gas. The pressure-volume relationships of the saturated fluid were also determined. It is shown that the use of published correlations on physical properties of reservoir .fluids can lead to gross errors when applied to systems containing large amounts of hydrogen sulfide. INTRODUCTION Equilibrium vaporization ratios for various components in naturally occurring crude oil and condensate systems have been reported in the literature.1,2,3,4 Recently, several papers have been published with emphasis on non-hydrocarbon components such as nitro- gen, carbon dioxide and hydrogen sulfide.5,6,7,8,9 The increased discovery of reservoir fluids having high concentrations of these non-hydrocarbon components, particularly hydrogen sulfide, has created a need for a further study of their phase behavior. Equilibrium vaporization ratios are known to vary with pressure, temperature, and overall composition of the system.'" It was anticipated that ratios for systems containing large amounts of hydrogen sulfide would differ from the ratios for systems containing small amounts of hydrogen sulfide. Therefore, the present work was undertaken in order to obtain reliable equilibrium vaporization ratios for the reservoir-fluid in question. PROCEDURE The procedure followed was evolved after considerable experimentation on methods of handling the very sour crude. It was found that drying agents (e.g. CaCl2 and CaSO4) absorbed an appreciable amount of hydrogen sulfide from the gas used to prepare the recombined samples. The concentration of hydrogen sulfide dropped as much as 10 mole per cent in a single pass through a 3-ft drying tube. It was also found that when undried gas was agitated with mercury in the PVT cell, a black scum, believed to be mercuric sulfide, was formed and the hydrogen sulfide content of the gas dropped several mole per cent. Because composition changes during a run could not be tolerated, separation of the mercury and sour fluid was necessary. In order to effect this separation, a stainless steel piston, equipped with Teflon O-rings, was placed in the PVT cell between the mercury and the sour fluid. This piston had to be constructed in three parts because

Jan 1, 1955

By J. L. Taylor, P. Duwez

PARTIAL phase diagrams of titanium with iron, cobalt, and nickel have been established by previous investigators.1-3 These diagrams seem to be reliable, at least for concentrations of titanium ranging from 0 to about 50 at. pct. More recently, Long and his collaborators have presented a tentative titanium-nickel diagram covering the titanium-rich side.' These various studies indicate that in each system three intermediate phases exist and correspond to the compositions Tia, TiX, and TiX2 (or TiX3). The purpose of this paper is to review the available information on the crystal structure of these phases and to give the results of additional X-ray diffraction studies. Previous Work A summary of the work of Wallbaum and his collaborators"-' is presented in table I. The first intermediate phase on the titanium-rich side of the three systems, with iron, cobalt, and nickel, is of the Ti2X type and has a face-centered cubic structure. Although it is stated that the unit cell contains 96 atoms: no lattice parameters are given. The second phase is centered around the compositions TiX for the three systems. The crystal structure of this phase is mentioned in a short note" as being body-centered cubic (CsCl type), but no parameters are given. The analogy between the three systems, which is perfect as far as the two phases of the type Ti2X and TiX are concerned, disappears at the titanium-poor end of the diagrams. In the system titanium- iron, TiFe2 has an hexagonal (MgZn2 type) struc-ture with the parameters given in table I. The existence of TiFe3 has also been reported8 (table I) but was questioned by other investigators2 and is also refuted by the present study. In the system titanium-cobalt, a phase corre-sponding to the composition TiCo2 has been investi-gated by Wallbaum and Witte6 who claim that the structure is cubic (MgCu2 type) for alloys slightly deficient in cobalt and hexagonal (MgNi2 type) for alloys slightly deficient in titanium. The parameters of the two phases are given in table I. In the system titanium-nickel, the nickel-rich phase corresponds to the composition TiNi3 and has been described as hexagonal7 with the parameters given in table I. The present investigation was initiated for the purpose of filling in the gaps in the knowledge con-cerning the structure of the various phases sum-marized in table I. Since the titanium used by Wallbaum and his collaborators was only 95 pct pure,' it was found desirable to redetermine the lattice parameters of the alloys prepared with a

Jan 1, 1951

By T. E. Leontis, D. H. Feisel

MAGNESIUM alloys containing rare earth metals have received considerable attention during the past several years because of the need for light alloys having high strength and creep resistance at elevated temperatures. Although much of the work reported earlier has dealt with alloys containing Mischmetal, it has been shown in two previous papersl, V hat distinctly different effects are produced by various rare earth metals and rare earth metal mixtures on the properties of magnesium. For example, much higher strengths are obtained in magnesium alloys containing didym-ium (essentially neodymium plus praseodymium) than in alloys made with Mischmetal, which contains all the rare earth metals in the proportions in which they occur naturally in the monazite ore. Mg-rare earth metal alloys are characterized by a relatively coarse grain size, which greatly impairs castability. The addition of zirconium as a second alloying ingredient has been shown8,7 to refine the grain size, which also produces a distinct improvement in the strength properties. Certain Mg-Mischmetal-Zr and Mg-Mischmetal-Zn-Zr alloy compositions which are currently being produced commercially have been discussed in dytail by Nelson and Strieter,8,4 who also present some in- formation on a Mg-low Ce-Mischmetal-Zr alloy, and by Nelson.8 A patent issued to Jessup, Emley, and Fisher9 emphasizes the superiority of Mg-didymium-Zn-Zr alloys over the corresponding alloys made with Mischmetal. The purpose of this paper is to present the results of an extensive investigation concerned with the effect of increasing amounts of zirconium on magnesium sand casting alloys containing several different rare earth metal mixtures in varying amounts. The effect of the addition of zinc to some of these alloys is also being reported. Preparation and Testing of Alloys The alloys studied in this investigation were prepared in small laboratory melts according to the melting procedures described by Nelson1" as the Crucible Method. Electrolytic magnesium having the composition shown in Table I was used as the starting material. The rare earth metal alloying ingredients used in preparing these alloys were essentially of the compositions listed in Table 11. Some of the didymium-containing alloys were prepared using a Mg-didymium hardener. The rare earth metal content of this hardener analyzed 1.2 pct Ce, 10.4 pct Pr, 80.8 pct Nd, and 7.6 pct La. The zirconium was added in one of three forms: 1) as sponge zirconium obtained from the Bureau of Mines; 2) as a fused salt consisting of 50 pct ZrCl, and 50 pct alkali chlorides from which the zirconium is reduced by the magnesium; or 3) as a Mg-Zr hardener. The alloying procedures and melt hand-

Jan 1, 1958

By Jack A. Crichton, Henry J. Gruy

This paper discusses methods used in the estimation of natural gas reserves and the general conditions under which the various methods are applicable. The factors used in estimating natural gas reserves are reviewed. Errors which have been found to occur frequently are listed. Introduction The estimation of natural gas reserves has become of paramount interest because of the increasing importance of gas in the nation's economy. Gas is a most desirable fuel, a fact substantiated by the continued rise in the market demand. In addition, new uses for gas are being developed by the chemical, plastic, and associated industries, and plants are being built to make gasoline from natural gas. These are a few of the factors contributing to the importance of the nation's natural gas reserves. With the increased importance of gas there is an increase in the need for reliable estimates of the magnitude and availability of natural gas reserves. These estimates are being used currently: (I) to determine which fields contain sufficient available reserves to justify the construction of pipe-line outlets to serve particular markets; (2) to design pipe lines necessary to serve those fields adequately;] (3) to determine the location of industrial and chemical plants; (4) to finance the development of gas properties, and the construction of gas pipe lines; (5) to determine fair and adequate depletion allowances and depreciation rates; (6) to justify applications for gas pipe lines before various regulatory bodies; (7) to determine the number of wells required to exploit the reserves most economically; (8) to aid in establishing values for the purchase or sale of gas properties, and for purposes of inheritance taxes; (9) to determine equities under unitized operations; (10) to provide a basis for calculating the economics of gas-cycling operations. History or Estimation of Natural Gas Reserves The natural gas industry in the United States had its beginning during 1826 when natural gas was used for lighting the city of Fredonia, N. Y. The first natural gas pipe line was a 25-mi]le wooden line constructed from hollowed logs, connecting West Bloomfield and Rochester, N. Y. There is no record of an attempt to estimate the gas reserve at West Bloomfield but an attempt was made to determine the capacity of the well by measuring the time required to 611 a large balloon. One of the earlier publications concerning estimation of natural gas reserves is the "Manual for the Oil and Gas Industry," published by the Treasury Department, United States Internal Revenue, in i9i9. The following methods of computing "gas depletion" are listed: (I) production decline of the gas well or property; (2) decline in open-flow capacity; (3) comparison with the life history of similar wells or properties, particularly those exhausted Art

Jan 1, 1949

By Tell Ertl

THE Piceance Creek Basin in northwestern Colorado is believed to contain the richest large deposit of oil shale in North America. The major portion, about 1650 sq miles, is bounded by the White River on the north, the Grand Hogback, which runs from Meeker to Rifle, on the east, the Colorado River to the south, and the drainage basin of Salt and Douglas Creeks on the west. The Basin is a plateau 7000 to 9000 ft high, composed of 3000 ft of the Green River series of Eocene age and surrounded by a steep escarpment of 1000 to 3000 ft. From the escarpment the beds dip gently toward the center. Although oil shale is found in all members of the Green River series, the rich thick beds are found chiefly in the Parachute Creek member. This is normally capped by 100 to 200 ft of the Evacuation Creek, the youngest member of the Green River series. Actually the Piceance Creek Basin oil shale is not a shale, nor does it contain oil. It is magnesium marlstone holding solid organic matter capable of being broken down by heat into gases, some of which can be condensed into oil. The marlstone is resilient nonporous rock, difficult to sample by pick or hammer and moil. Many companies and individuals prospected the Colorado oil shale shortly after the first World War,' see Fig. 1, but because of the discovery of large quantities of petroleum in the late 1920's in Cali- fornia, Oklahoma, and East Texas, interest in oil shale development waned and did not revive until World War 11. In 1944 the writer, employed by the Bureau of Mines, prospected the high grade oil shale in numerous places along the southern outcrop of the Piceance Creek Basin. Several channel samples about 100 ft in length were cut, see Fig. 2. An eight-man crew needed a week to cut a satisfactory channel 80 ft long in the cliff face. The Phillips Petroleum Co., the Union Oil Co. of California and others also prospected the oil shale outcrop. In 1945 the Bureau of Mines initiated a core drilling program for the purpose of obtaining accurate samples from the Piceance Creek Basin. The U. S. Geological Survey set up a program for the geological study of the Basin that is still going on." Until the end of 1951 a total of 31 holes was drilled for core with diamond drills, and, in addition, cuttings through the oil shale have been obtained from 4 gas wells drilled by standard rotary oil well rigs. The Bureau of Mines drilled 12 of the holes, the Union Oil Company of California 8, the Standard Oil Company of California 6, the Sun Oil Company 3,

Jan 1, 1953

The Cuajone and Toquepala copper projects are located in the extreme southern area of Peru. Since 1960, Southern Peru Copper Company has operated the Toquepala open -pit mine, flotation mill, 110 smelter, townsites, power plants, and railroad. Toquepala and 10, the smelter and port location, are connected by a 110-mile-long (176 lun) railroad. Much of Toquepala's infrastructure has been used for the Cuajone project. Cuajone, at an elevation of 11,400 ft (3475 m), required five standard-guage railroad tunnels with a combined length of 17 miles (27.2 km) to connect with Toquepala so concentrates could be shipped to the no smelter. The total cost of Cuajone is estimated at $726 million for a designed annual capacity of 180,000 tons of copper, equivalent to about $4,000 per ton of installed production capacity. This relatively low cost per ton, by today's standards, has been made possible through the use of the 110-to Toquepala railroad, the ability to expand the 110 copper smelter, and other favorable factors. To mine the 468 million tons of copper sulfide or e at a grade of 1.0% copper, approximately 24 1 million tons of waste were stripped- before mining of ore to supply the new Botiflaca 45, 000 ton per day concentrator. The mining rate must exceed 300,000 tons of waste plus ore per day to maintain the 45, 0 00 tpd sulfide ore milling rate which was to be reached at the end of 1976. Waste stripping is done with 15 cu yd electric shovels and 120 -ton trucks. Ore mining is done with 8 and 9 yd shovels. A railroad connects the pit with the 60 in. by 89 in. Allis-Chalmers gyratory crusher. Side-dump railroad cars of 50.cu yd capacity dump onto a 0 16 ft 9 in. long (5. 1 m) grizzly inclined at 40º with 7 to 8 in. (178 to 203 rnrn) bar spacings. The grizzly is divided into two 22 ft 4 in. (6.8 m) wide sections and two side -dump railroad cars discharge simultaneously into the 150-ton capacity dump pocket. A Barco rock manipulator is used for breaking or removing oversize from the dump pocket. The bin receiving the grizzly undersize has a capacity of 5,000 tons, and the pocket beneath the crusher holds 900 tons. Each is equipped with an 84 in. apron feeder, which feeds a 60 in. (1.52 m) conveyor belt to the 150,000 ton coarse ore stockpile, where the ore is distributed by a 72 in. (1. 83 m) tripper conveyor. The 45, 000 live tons in the coarse ore stockpile are reclaimed by twelve 48 in. (1. 22 m) apron feeders. Maintenance on the crusher eccentric is made easy by an eccentric

Jan 1, 1978

By Tell Ertl

THE Piceance Creek Basin in northwestern Colorado is believed to contain the richest large deposit of oil shale in North America. The major portion, about 1650 sq miles, is bounded by the White River on the north, the Grand Hogback, which runs from Meeker to Rifle, on the east, the Colorado River to the south, and the drainage basin of Salt and Douglas Creeks on the west. The Basin is a plateau 7000 to 9000 ft high, composed of 3000 ft of the Green River series of Eocene age and surrounded by a steep escarpment of 1000 to 3000 ft. From the escarpment the beds dip gently toward the center. Although oil shale is found in all members of the Green River series, the rich thick beds are found chiefly in the Parachute Creek member. This is normally capped by 100 to 200 ft of the Evacuation Creek, the youngest member of the Green River series. Actually the Piceance Creek Basin oil shale is not a shale, nor does it contain oil. It is magnesium marlstone holding solid organic matter capable of being broken down by heat into gases, some of which can be condensed into oil. The marlstone is resilient nonporous rock, difficult to sample by pick or hammer and moil. Many companies and individuals prospected the Colorado oil shale shortly after the first World War,' see Fig. 1, but because of the discovery of large quantities of petroleum in the late 1920's in Cali- fornia, Oklahoma, and East Texas, interest in oil shale development waned and did not revive until World War 11. In 1944 the writer, employed by the Bureau of Mines, prospected the high grade oil shale in numerous places along the southern outcrop of the Piceance Creek Basin. Several channel samples about 100 ft in length were cut, see Fig. 2. An eight-man crew needed a week to cut a satisfactory channel 80 ft long in the cliff face. The Phillips Petroleum Co., the Union Oil Co. of California and others also prospected the oil shale outcrop. In 1945 the Bureau of Mines initiated a core drilling program for the purpose of obtaining accurate samples from the Piceance Creek Basin. The U. S. Geological Survey set up a program for the geological study of the Basin that is still going on." Until the end of 1951 a total of 31 holes was drilled for core with diamond drills, and, in addition, cuttings through the oil shale have been obtained from 4 gas wells drilled by standard rotary oil well rigs. The Bureau of Mines drilled 12 of the holes, the Union Oil Company of California 8, the Standard Oil Company of California 6, the Sun Oil Company 3,

Jan 1, 1953

By R. A. Bell, R. Schultz, P. G. Hallof

The Ballyvergin area is located in County Clare on the southwest coast of Ireland. It is one of six areas in County Clare in which mining operations were carried out during the last century. The ores mined were high grade Cu-Pb-Ag deposits in the form of small fracture fillings and gash veins in the lower Carboniferous limestones. The zone of primary economic interest is situated on the north limb of a geosyncline which plunges moderately to the southwest. The zones of mineralization previously mined were associated with local structures and folds, and the initial geophysical investigations took the form of reconnaissance induced polarization measurements around, and between, the old mines. This work located an anomaly which, on drilling, resulted in a small extension of the Pb-Cu ore at the Ballyvergin mine. However, a potentially more important zone of mineralization resulted from the drilling of another IP anomaly near Ballyvergin. This wide anomaly was found to be a domal shaped deposit of disseminated chalcopyrite located at a depth of more than 100 ft. The deposit is controlled by local folding in the sediments and is of a type previously unknown in the area. More IP investigations are under way to locate other deposits of the same type. The Ballyvergin area is located in County Clare, about 35 miles northeast of Shannon Airport, near the Atlantic west coast of Southern Ireland (Fig. 1). Interest in the area stems from a number of occurrences of small, but high grade, Pb-Ag deposits. From the summer of 1960 to the spring of 1961, Irish Base Metals carried out a comprehensive exploration program on a 38-sq mile concession in east-central County Clare in an attempt to locate additional deposits of this type. Field operations consisted of geologic mapping, geochemical soil and stream sampling, geophysical surveying and diamond drilling. The geophysical program consisted primarily of detailed induced polarization (IP) surveys in the general vicinity of old mine workings, supplemented by electromagnetic and self-potential investigations. Subsequent diamond drilling of a well defined IP anomaly close to the old Ballyvergin mine disclosed a sizeable deposit of low grade disseminated copper, a type of deposit previously unknown in this area. REGIONAL GEOLOGY Topography: The topography is of the Karst type with low regional relief. The northern parts of the area are covered almost completely with glacial deposits including a large number of drumlins. Elsewhere the overburden is patchy and only moderately deep. A close network of roads makes every part of the area readily accessible, and rail and harbor facilities are available nearby — Fig. 2. Stratigraphy: The area was mapped on a reconnaissance basis by the Geological Survey of Ireland during the latter part of the 19th century at scales of 1 and 6 in. to the mile. Mapping is complicated in

Jan 1, 1962

By M. A. Westbrook, J. F. Redmond

A method is presented for obtaining porosities of consolidated formations from the drill returns. The method provides a means of determining the bulk volume of a large number of particles, such as drill cuttings, by employing a capillary diaphragm for removal of surplus surface liquid from saturated cuttings having pores of capillary size, which reduces tile amount of error present in former attempts to determine the porosity of drill cuttings. The method makes it possible to obtain a considerable amount of supplementary data on consolidated formations. Introduction Porosity is a direct measure Of the volume of the voids in a formation. It may be used for estimating the permeability of a formation provided that a correlation of these two properties has been obtained from the analysis of cores from the particular formation, and it forms a desirable aid in interpreting electric logs.1 These useful applications have emphasized the importance of developing a method for determining the porosity of the formations penetrated by a well by some means other than coring, for even in exploration wells it is neither economical nor practical to core all formations. Also, in wells where at the outset the coring program appears comprehensive, it is frequently found that, after certain layers are drilled. more complete information is required for evaluation. Porosity values, if obtainable, would be of great assistance in such cases. In soft formations it is usually possible to obtain porosities after drilling with cores taken by side-wall coring devices. In hard consolidated formations, that coring procedure is not alway practicable and other methods for determining porosities must be resorted to. A first choice is the examination of drill cuttings. if an analytical procedure is available that is both accurate and reasonably rapid. Such a procedure has been devised and is applicable to sand and limestone cuttings having pores of capillary size. Although imp,ovements can yet be made, it is believed that the new technique is sufficiently well developed to warrant description, Preparation of Sample The well samples containing the cuttings representative of the particular intervals are first washed through a No' 6 gauge screen. The cuttings remaining on the Screen are large enough to use lor the porosity measurements' From the sized sample, the cuttings to be examined are separated from the shale and Other extraneous particles. It is recommended that 10 to 15 c.c. of the selected cuttings be used for measurements, although only 4 to 5 c c. were used to make the comparative tests described later in this article. These cuttings are extracted and dried by the same methods used for preparing core samples for porosity and other measurements. The separation, which is at present being carried out by hand, is the most tedious

Jan 1, 1946