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By T. B. Massalski, H. W. King

An hcp phase may be induced by cold working the ß&apos; phase of the Ag-Zn system. This phase reverts to ß&apos; on subsequent aging. No phase change occurs on cold working the o phase, but ß&apos; is formed when the deformed alloy is subsequently aged at room temperature. It is concluded that for alloys near 50 at pct Zn the ordered bcc ß&apos; phase is the equilibrium structure at room temperature. WhEN the disordered bcc ß phase of the Ag-Zn system is cooled to temperatures below 258o to 274oC, it transforms to a complex hexagonal phase <o.1,2 The nature of the o ß=o transformation has been the subject of some discussion,2&apos;3 and the structure of o has been described in detail.&apos; The latter phase appears to be stable on aging at room temperature but decomposes following cold work. When alloys containing approximately 50 at. pct Zn are rapidly quenched from the 0 phase field, the ß ? o transformation may be suppressed; but the ß phase undergoes an ordering reaction (ß ? ß&apos;). The ß&apos; structure may also be obtained as a result of cold working and aging at room temperature.4 Kitchingman, Hall, and Buckley4 have suggested that the decomposition of (o following cold work proceeds in two stages, (o ? ß followed by ß ? ß&apos;, but did not confirm this by experiment. When the ordered &apos; phases in the systems Cu-Zn5 and Ag-Cd6 are cold worked, they become unstable and transform to a close-packed hexagonal phase (( ) indicating that when order is destroyed in a ß&apos; structure the close-packed hexagonal phase may in many cases be more stable. It thus became of interest to study more closely the effect of cold work and annealing on the stability of both the ß&apos; and o phases in a Ag-50 at. pct Zn alloy. Predetermined weights of spectroscopically-pure Ag and Zn, supplied by Johnson and Matthey, were melted and cast under 1/2 atm of He in transparent vycor tubing. The ingot was homogenized for 1 week at 630°C and quenched into iced brine. Since mechanical polishing was found to induce a phase change, sections were first polished at room temperature, sealed in tubes under 1/2 atm of He, reannealed for several days at 630o or 200°C and then quenched into iced brine. Sections of the alloy thus prepared were found to be homogeneous when examined under the microscope. The sample quenched from 630°C (ß -phase region) was pink in color, whereas the sample quenched from 200°C (o-phase region) was silver. The latter sample showed the characteristic hexagonal anisotropy when examined under polarized light. Filings of the alloy were examined at room temperature, after various heat treatments, using an RCA-Siemens Crystalloflex IV diffractometer with filtered CuKa radiation. The X-ray reflections from flat powder specimens quenched from 630o and 200°C and sieved through 230 mesh were recorded graphically at a scanning speed of 1/2 deg per min. The resultant patterns are shown in Figs. 1(a) and 1(b) and may be identified as those of the 8&apos; and <02 structures respectively. The lattice parameter of the ß&apos; phase was determined as 3.1566Å.* This value compares very well withthatto be expected for a 50 at. pct Zn alloy from the data of Owen and Edmunds? and indicates that no loss of Zn occurred during casting. In order to study the effect of cold work upon the ß&apos; and o phases, filings made at room temperature and sieved through 230 mesh were mounted immediately in the diffractometer-i.e., without a strain-relief anneal. Changes in structure on subsequent aging were followed by scanning repeatedly over the regions of the low index reflections of the ß&apos; and o structures-i.e. , 28 from 35 to 44 deg. Immediately after filing the 8&apos; specimen, additional diffraction peaks were observed in the low-index region of the pattern, as shown in Fig. 1(c). These additional peaks do not coincide with those of the o structure, Fig. l(b), but may be indexed as the (10.0), (00.2), and (10.1) reflections of an hcp phase (<) with nearly ideal axial ratio. However, this hexagonal phase appears to be very unstable since within a very short time at room temperature it reverts back to the ordered ß&apos; phase, the reversion being complete within seven hours. The 5 ? ß&apos; reversion reaction is, therefore, very similar to those already reported in Cu-Zn5 and Ag-Cd6 7&apos;alloys. The action of filing caused the deformed surface of the originally pink ingot to become silver in color, indi-cating that the ( phase possesses similar reflecting properties to the o phase. Hence, the subsequent

Jan 1, 1962

Consolidated Gold Fields Limited published annually an excellent reference, GOLD 1978, GOLD 1979, giving the Supply and Demand for Gold, Recent Developments and Prospects, Soviet Gold Production, etc. This outstanding reference is authored by Christopher Glynn, Investment Department, London, Great Britain. The 1978 Report marked the tenth anniversary of Gold Field&apos;s review of world gold market developments; and from it and the 1979 report, the following information was derived. The recovery of gold is widespread in the Soviet Union. Originally, gold was mined principally in the Urals, but in the last few years several major deposits have been discovered in the southwestern areas of the Soviet Union. One of the most dramatic discoveries has been the Muruntau deposit in Western Uzbekestan. This deposit, discovered in 1958, is reported to be the largest and among the lowest cost producers in the Soviet Union. It is located in Armenia, approximately 750 km (465 miles) northeast of the Iran-Afghanistan border, lying in the center of the Kyzylkurn (Red Sands) desert at the foot of Muruntau Mountain. Free gold occurs in both fine and coarse size in quartz veins up to 20 m (66 ft) thick associated with a small percentage of sulfides, mainly arsenopyrite. The ore zone constitutes a large gold-enriched stock work of about 4 sq krn (1.5 sq miles). The development of Muruntau was a major undertaking with open -pit development and construction of the mill and refinery complex started early in 1967, and the first gold bar poured in mid-1969. At the end of the first construction stage in 1970, the mill building was an imposing structure about 38 m (125 ft) high and 330 (1,080 ft) in length housing, probably, 11 parallel milling circuits. The first construction stage also included six 50 m (165 ft) diameter thickeners and 30 Pachuca tanks. The original mill complex was tripled in size after large additional gold reserves were discovered at a depth of 600 m (1,970 ft); and the deposit is now being exploited by both open- pit and underground workings. Ore is ground in semi-autogenous mills with the free gold being recovered into a high-grade concentrate on shaking tables. Table tailings are purnped to duplex spiral classifiers in closed circuit with the grinding mills. Classifier overflow is then thickened before being transferred to the Pachuca building where cyanidation takes place. An ion exchange resin is then added in a countercurrent

Jan 1, 1981

By M. Sheffield

This paper presents a technique lor predicting the flow of oil, gas and water through a petroleum reservoir. Gravitational, viscous arid capillary lorces are considered, and all fluids are considered to be slightly compressible. Some theoretical work concerning the fluid flow in one-, two- and three-space dimensions is given along with example performance predictions in one- and two-space dimensions. INTRODUCTION Since the introduction of high speed computing equipment, one of the goals of reservoir engineering research has been to develop more accurate methods of describing fluid movement through underground reservoirs. Various mathematical methods have been developed or used by reservoir engineers to predict reservoir performance, 193-5,7,8 The work reported in this paper extends previously published work on three-phase fluid flow (1) by including a rigorous treatment of capillary forces and (2) by showing certain theoretical mathematical results proving that these equations can be approximated by certain numerical techniques and that a unique solution exists. DISCUSSION The method of predicting three-phase compressible fluid flow. in a reservoir can be summarized briefly by the following steps. 1. The reservoir, or a section of a reservoir, is characterized by a series of mesh points with varying rock and fluid properties simulated at each mesh point. 2. Three partial differential equations are written to describe the movement at any point in the reservoir of each of the three compressible fluids. All forces influencing movement are considered in the equations. 3. At each mesh point, the partial differential equations are replaced by a system of analogous difference equations. 4. A numerical technique is used to solve the resulting system of difference equations. Capillary forces have been included in two-phase flow calculations.1,4,8 The literature, however, does not contain examples of prediction techniques for three-phase flow that include capillary forces. Where capillary forces are considered, each of the three partial differential equations previously discussed has a different dependent variable, namely pressure in one of the three fluid phases. Therefore, three difference equations must be solved at each point in the reservoir. Where large systems of equations must be solved simultaneously, an engineer might question whether a unique solution to this system of equations actually exists and, if so, what numerical techniques may be used to obtain a good approximation to the solution. It is shown in the Appendix that a unique solution to the three-phase flow problem, as formulated, always exists. It is also shown that several methods may be used to obtain a good approximation to the solution. The partial differential equations and differenceequations used are shown in the Appendix. Matrix notation has been used in developing the mathematical results. Two sample problems were solved on a CDC 1604. They illustrate the type of problems that can be solved using a three-phase prediction technique. SAMPLE ONE-DIMENSIONAL RESERVOIR PERFORMANCE PREDICTION A hypothetical reservoir was studied to provide an example of a one-dimensional problem that can be solved. Of the several techniques available, the direct method of solution as shown in the Appendix was used. The reservoir section studied was a truncated, wedge-shaped section, 2,400 ft long, with a 6&apos; dip. (A schematic is shown in Fig. 1.) This section was represented by 49 mesh points, uniformly spaced at 50-ft intervals. The upper end of the wedge was 2 ft wide, and the lower end was 6 ft wide. The section

Jan 1, 1970

By A. L. Holley

There are regularly manufactured in the eleven Bessemer steel rail mills of the United States, 119 patterns* of steel rails, of 27 different weights per yard. This list does not include patterns which, although still largely in use, are regarded by experts as obsolete, and which would swell the number to nearly 300; nor does it include all the patterns for which rolls are kept on hand to fill a passible demand; nor does it include extra patterns rolled in one finishing groove by opening or closing the rolls so as to get different weights with the same contours. The list embraces only those separate patterns which are subject to current orders. How thoroughly modern these patterns ere, is shown by the fact that of the whole 119, there are but five patterns of conspicuously bad shape; all the rest more or less completely illustrate the standard features,—a heavy head, light web and Hanges, and a good angle to hold the fish-plate. Sixty-two per cent. of the patterns have the "Chanute" head, which was not designed until 1874.† Sixty-four per cent. of the 119 patterns are embraced under five weights per yard,; three only of these vary from standard type; there are thus 76 patterns, all of them modern and standard, to represent five different weights, for which five patterns would perfectly answer. Of the 60lb. rails, there is only one of the pear-head type, while a dozen of the bevelled head templets cannot be distinguished from each other

Jan 1, 1881

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus become citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil. EXTENSIVE beds of a soft aluminiferous phosphate lie in the Bartow-Pembroke region of Florida. Although the extent of the deposit is unknown, it is thought that the equivalent of at least five million tons of material containing 25 pct P,Os exists on one large mine property alone, and soft phosphates similar in nature are known to occur elsewhere in the state. This aluminum phosphate, unlike fluorapatite, is rendered fairly soluble in neutral ammonium citrate solution merely by heating it at a temperature below 600 °C, a property made the basis of a process patent by the junior author.&apos; The possibility of producing an available form of phosphorus from what has hitherto been a worthless natural phosphate prompted the Bureau of Plant Industry, Soils, and Agricultural Engineering to make a brief study of the Pembroke phos- phate during the war years with a view towards determining the optimal temperature for heat treatment and the reactions involved in the process. The results of this study supplemented by data and information furnished by the junior author are presented in this paper. Description of Natural Phosphate: The phosphate with admixed quartz sand and siliceous matter occurs as a low-grade (8 to 9 pct P2O5) clay-like material that can be beneficiated cheaply by making a water separation of the very fine material from the sand, floating off the fine material, settling the suspension to a thick slurry, and finally de-watering the slurry by vacuum filtration followed by drying. The product dried at 100 °C contains about 16 pct water and 25 pct P2O5, about 1/12 of which is citrate soluble. Partial analyses of representative samples of the crude ore and corresponding concentrate are given in table I. The concentrate is light yellow in color and even after being dried at 100°C sticks very noticeably to laboratory grinding and screening equipment. Under the microscope the ground material is predominantly light brown crystalline aggregates with index of refraction near 1.61. The principal phosphate mineral constituent was identified as pseudo-wavellite with admixed phosphosiderite.2 Pseudo-

Jan 1, 1951

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus become citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil. EXTENSIVE beds of a soft aluminiferous phosphate lie in the Bartow-Pembroke region of Florida. Although the extent of the deposit is unknown, it is thought that the equivalent of at least five million tons of material containing 25 pct P,Os exists on one large mine property alone, and soft phosphates similar in nature are known to occur elsewhere in the state. This aluminum phosphate, unlike fluorapatite, is rendered fairly soluble in neutral ammonium citrate solution merely by heating it at a temperature below 600 °C, a property made the basis of a process patent by the junior author.&apos; The possibility of producing an available form of phosphorus from what has hitherto been a worthless natural phosphate prompted the Bureau of Plant Industry, Soils, and Agricultural Engineering to make a brief study of the Pembroke phos- phate during the war years with a view towards determining the optimal temperature for heat treatment and the reactions involved in the process. The results of this study supplemented by data and information furnished by the junior author are presented in this paper. Description of Natural Phosphate: The phosphate with admixed quartz sand and siliceous matter occurs as a low-grade (8 to 9 pct P2O5) clay-like material that can be beneficiated cheaply by making a water separation of the very fine material from the sand, floating off the fine material, settling the suspension to a thick slurry, and finally de-watering the slurry by vacuum filtration followed by drying. The product dried at 100 °C contains about 16 pct water and 25 pct P2O5, about 1/12 of which is citrate soluble. Partial analyses of representative samples of the crude ore and corresponding concentrate are given in table I. The concentrate is light yellow in color and even after being dried at 100°C sticks very noticeably to laboratory grinding and screening equipment. Under the microscope the ground material is predominantly light brown crystalline aggregates with index of refraction near 1.61. The principal phosphate mineral constituent was identified as pseudo-wavellite with admixed phosphosiderite.2 Pseudo-

Jan 1, 1951

By A. M. Nicholas

WHEN attempting to lift mill pulp containing a considerable percentage of wolframite, in an ordinary bucket elevator, difficulty was encountered from the tendency of the tungsten minerals to settle, on account of their high specific gravity. Lifts not exceeding 20 ft. (6m.) could be accomplished without particular difficulty, because there was insufficient time for consolidation of the heavy minerals in the bottom of the bucket; but with higher lifts, the heavy tungsten minerals would settle so solidly that when the bucket turned over at the top of the elevator the contents could be only partially dumped. In this case it ,was necessary to lift the material a distance of 34 ft. (10m.); hence some means had to be adopted to prevent settling, at least to such an extent that the material could be dumped from the buckets. To reduce the carrying time to a sufficient extent would have required a belt speed of 475 ft. (144.7m.) per minute, which was not feasible. It was decided to try, by vibrating the belt about midway of its span, to keel) the material sufficiently agitated during elevation to prevent settling. Underneath the rising side of the belt was placed a 12-in. (30.48-cm.) idler pulley, 18 ft.-(5.5 in.) up in the total lift of 34 ft. The idler pulley was set eccentric by 3/4 in. (19 mm.) and it was hoped that the vibration thus imparted to the belt, running at a speed of 280 ft. (85 m.) per minute, would prevent settling in the buckets. It was found that the pressure of the belt on the idler, due to the small inclination of the elevator, was not sufficient to overcome sliding on the idler, and the agitation was insufficient to accomplish the desired purpose. The idler was then connected to the drive shaft of the elevator through an intermediate pulley, gearing down to a speed of 20 r.p.m., so that a positive vibration was imparted to the belt; this imparted enough motion to the belt to prevent settling and the contents of buckets clumped satisfactorily.

Jan 2, 1918

By Gilbert Doan

AN extensive program of investigation is being carried out at Lehigh University in the study of arcs and arc welds of high-purity iron1, spon-sored by the Engineering Foundation. The part of that program reported in the present paper deals with welds made of high-purity iron in an argon atmosphere and for comparison with them welds made of the same iron in ordinary air. Welds of commercial steel also were made in argon and in air. The primary purpose of the study is to discover the basic physical constants of iron welds when not contaminated either by impurities in the iron or by the action of oxygen and nitrogen of the air during welding. Upon these constants can be founded such future studies as will determine what effects the various impurities and alloy elements present in steel have upon its welding characteristics, and what influence is exerted by the action of oxygen and nitrogen. The welding of steel involves such a multitude of variables, both of composition and of procedure, that development in the fabrication of this most important metal has necessarily been slow, wasteful, and in many instances discouraging. In the present investigation, the simplest possible condition has been selected; namely, iron practically free from contamination and a nonparticipating atmosphere, the inert gas argon. This simplification reduces the number of variables to a point where more rigid control of the system is possible. Although this study is significant for the contributions it makes to the science of steel fabrication, yet it is hoped that it will not be without value also in increasing knowledge of the nature and behavior of iron and steel in general. From the standpoint of open-hearth practice, and to

Jan 1, 1936

By J. W. Rutter, K. T. Aust

In previous studies of grain boundary migration in zone-refined lead, the authors used bicrystal specimens consisting of a striated crystal which was grown from the melt, and an adjacent striation-free crystal, introduced by artificial nucleation and growth.1 While this method permits the study of the motion of individual grain boundaries, it does not provide control of the relative orientations of the grains. The present note will describe a technique for controlling the orientations of the two crystals in this type of specimen. The technique consists essentially of placing a striated crystal and a striation-free crystal of controlled orientations end-to-end in a graphite trough, then melting a short zone at the junction of the two crystals and allowing it to freeze to form the desired grain boundary. The apparatus used to carry out this process is illustrated in Fig. 1. It consists of a trough milled from high-purity graphite,with grooves in the underside for the placement of thermocouples. The graphite piece fans out on one end at the level of the bottom of the trough; the sides of the trough are completed in this region by the attachment of a mating plate with a slot cut at any desired angle to permit reorientation of the crystal placed at this end of the assembly. The joint between the crystals is made at or near the point where the slotted plate joins the rest of the trough. The thermocouple slots are deepened in this region so that the thermocouples are separated from the melt by only 1/32 in. of graphite. An induction heater, with suitable temperature control, is used to obtain the molten zone. The two single crystals used are first chemically polished in a solution consisting of eight parts glacial acetic acid and two parts 30 pct hydrogen peroxide. They are then placed in the trough with the ends to be joined at the position of the thermocouples. Next, cooling is applied to the two crystals by means of air

Jan 1, 1962

By AIME AIME

THOUGH the Annual Meeting of the Institute-officially numbered 158 on the records was delayed a bit at the start by low steam pressure on the locomotives bringing members to New York, the crowd that finally arrived more than lived up to expectations, and the technical program had few difficulties because of absent authors or lack of competent discussers. The transportation difficulties were occasioned by the fact that Monday, Feb. 15, was the third coldest day in the 72 year history of the New York Weather Bureau, the official temperature being 8 below zero. The New York Central&apos;s premier train, the 20th Century, due at 9:30 a.m., arrived about 6:30 p.m., and the Commodore, another crack train from Chicago, was about equally late.

Jan 1, 1943

By W. M. Weigel

Salt production in Louisiana and Texas at the present time is entirely from salt domes of the interior and coastal groups. Before and during the Civil War salt was recovered from numerous salines and salt springs by evaporation in open kettles. The location of these in nearly every instance was near what is now known to be a salt dome, and the source of the salt in the salines and spring waters was that in the salt core. The tops of many of the shallower domes have been subjected to erosion1. The discovery that the salt occurred as large masses of rock salt in the form of domes was made in May, 1802, at Avery Island, La., by John Marsh Avery, grandson of the original owner, John C. Marsh, who built the old salt works in 18122. The first shaft for mining was sunk on the Avery dome in 1867 by Chouteau and Price. It was 90 ft. deep, about 58 ft. being in solid salt. It was abandoned in 1870. There are three general groups or fields of salt domes; interior Louisiana in northern Louisiana, interior Texas in northeastern Texas, and the coastal domes nearer the Gulf Coast and extending from the Mississippi River to the Rio Grande. This last group contains by far the greatest number of domes. As many of the coastal domes especially are prolific producers of petroleum and a few of sulfur, their geology has been intensively studied and fully covered in the literature. The depth to the top of the salt varies from near the surface, where shallow ground waters have dissolved the salt to just below recent deposits, to several thousand feet, where the depth has been cstimated only by geophysical methods. The diameter of the salt core varies from less than 1/2 mile to over 2 miles. Only domes where the salt is comparatively near the surface have been developed for commercial salt. Three deeper domes, which will be described later, have recently been developed or are in process of development, as a source of brine for chemical use. Fig. 1 shows the location of the domes so far developed for commercial salt and brine. Nos. 1, 2, 4, 7, 8, 9 and 10 are in the Gulf Coastal field,

Jan 1, 1938

By W. M. Weigel

Salt production in Louisiana and Texas at the present time is entirely from salt domes of the interior and coastal groups. Before and during the Civil War salt was recovered from numerous salines and salt springs by evaporation in open kettles. The location of these in nearly every instance was near what is now known to be a salt dome, and the source of the salt in the salines and spring waters was that in the salt core. The tops of many of the shallower domes have been subjected to erosion1. The discovery that the salt occurred as large masses of rock salt in the form of domes was made in May, 1802, at Avery Island, La., by John Marsh Avery, grandson of the original owner, John C. Marsh, who built the old salt works in 18122. The first shaft for mining was sunk on the Avery dome in 1867 by Chouteau and Price. It was 90 ft. deep, about 58 ft. being in solid salt. It was abandoned in 1870. There are three general groups or fields of salt domes; interior Louisiana in northern Louisiana, interior Texas in northeastern Texas, and the coastal domes nearer the Gulf Coast and extending from the Mississippi River to the Rio Grande. This last group contains by far the greatest number of domes. As many of the coastal domes especially are prolific producers of petroleum and a few of sulfur, their geology has been intensively studied and fully covered in the literature. The depth to the top of the salt varies from near the surface, where shallow ground waters have dissolved the salt to just below recent deposits, to several thousand feet, where the depth has been cstimated only by geophysical methods. The diameter of the salt core varies from less than 1/2 mile to over 2 miles. Only domes where the salt is comparatively near the surface have been developed for commercial salt. Three deeper domes, which will be described later, have recently been developed or are in process of development, as a source of brine for chemical use. Fig. 1 shows the location of the domes so far developed for commercial salt and brine. Nos. 1, 2, 4, 7, 8, 9 and 10 are in the Gulf Coastal field,

Jan 1, 1938

By J. L. Lamon, W. Crafts

Study with the electron microscope of the carbides in vanadium-chromium-molybdenum steels after tempering up to 1000 hr at 600 teelsto 1400°F confirmed that alloy carbides are formed at the secondary hardening temperature by decomposition of the plate-like iron carbides. It was also demonstrated that vanadium carbide persists as much smaller particles than do chromium- or molybdenum-bearing carbides. Conditions conducive to the formation of fine vanadium carbides are indicated to be favorable for high temperature strength. IN order to determine the effects of long exposure at high temperatures on vanadium-bearing steels, a survey has been made of their hardness and carbide structure. The behavior of carbides in the tempering of martensite was studied by X ray diffraction and electron microscope examination of electrolytically extracted residues in greater detail than in an earlier investigation.&apos; A group of steels with about 0.25 pct carbon and containing chromium up to 5 pct, molybdenum up to 1 pct, and vanadium up to 1 pct was either quenched or annealed and then tempered for peri- ods of up to 1000 hr at 600° to 1400°F. Their hardness after tempering agreed with the Hollomon and Jaffe2 relation of equivalency of time and temperature, and with the degree of secondary hardening predicted from composition. Further, the appearance of the carbides indicated that the time and temperature equivalency relation was also applicable to the degree of carbide development. The mechanism of the tempering of martensite was demonstrated more clearly than in the earlier study. It was confirmed that carbides develop from martensite as poorly defined plates of the Fe2C type carbide followed by thickening of the plates with a transition to Fe,C. Finally the plate structure deteriorates into a lacy mass from which alloy carbides emerge as chunky particles that grow slowly with further increase of tempering temperature. Vanadium carbide derived from tempered martensite was found in characteristically small particles that tended to grow very slowly. The addition of chromium or molybdenum to a steel with predominant vanadium carbide tended to introduce carbides of a chromium- or molybdenum-bearing type having a somewhat larger particle size. The Cr,C, type carbide particles were larger than those of the V,C, type and somewhat smaller than the carbides in steel containing both Cr,C and M,C. Similar observations were made of the carbides in the pear lite of annealed steels. It appeared that high temperature properties would be benefited by the retention of the fine carbide particles that result from a balance of composition and heat-treatment designed to produce a maximum amount of vanadium carbide. Procedure: The steels used in the investigation were made with a base of Armco iron in a high-frequency furnace at the Union Carbide and Carbon Research Labs., Inc. The steels were deoxidized

Jan 1, 1951

By S. H. Ash

More than 100 minerals are mined and processed in the U. S. Management and labor have negotiated wage-scale agreements that have balanced wages and affected cost of labor in such a manner that comparisons can be made of transportation costs. Transportation of materials underground has become of vital importance. This report describes underground haulage methods and equipment, presents cost analyses, and discusses future plans for underground transportation in metal mines. It does not cover hoisting in shafts or slopes by cage, skip, or cars. Advancements have been made by the metal mining industry in lowering transportation costs in several mines, making it possible to mine orebodies or portions of orebodies not considered economically recoverable a few years ago. Numerous reports have been written on transportation at metal mines; this report covers recent haulage at some representative mines throughout the U.S. The term metal mine is used to include all noncoal mines from which up-to-date information was obtainable.

Sep 1, 1956

By J. W. Bolton

THIS paper discusses some fundamental metallurgical principles involved in production of sound cast bronze. In a previous paper the writers advanced the theory that "oxidation" in bronze castings is due to incipient shrinkage, and showed the effect of reducing melting atmospheres. In the present paper the effects of certain impurities and of actual oxidizing conditions are shown. The appendix deals with the appearance of various inclusions. For many years the prevailing opinion has been that unsoundness, dark colored fractures and other phenomena accompanying porosity and weakness in bronzes are due to oxidation. The actual troubles are caused by fissures of intercrystalline type, which are often mistaken for intercrystalline films. These weaken the metal and make it porous. Grave doubt regarding the accuracy of the oxidation theory appears when several research papers presented within the last 10 years are reviewed critically. In 1919, Comstock conducted metallographic researches, attempting to identify "oxides" in synthetically prepared metals. He found that oxides of tin, aluminum, zinc, etc. are different from the intercrystalline films (or cavities) to which porosity is due. Apparently he believed that these "oxide films" may be caused by volatile oxides of zinc or of phosphorus or by dissolved gases thrown out of solution during solidi-fication of the metal. In 1923, Woyski and Boeck3 definitely questioned the accuracy of the oxidation theory and indicated the danger from reducing atmospheres. They say that "oxidation, gassing and shrinkage may produce effects very similar."

Jan 1, 1930

By C. D. Stahl, S. M. Farouq Ali, W. E. Culham

One- and two-dimensional mathematical models have been developed that simulate transient, two-phase flow of hydrocarbon mixtures in porous media in a manner that accounts for interphase mass transfer. Numerical simulations of one-dimensional depletion-drive experiments using a two-component hydrucarbon fluid were used to establish the validity of the mathematical models. In addition, the experimental and numerical data were used to demonstrate that production rate had a relatively insignificant effect on the recovery of individual hydrocarbon components from the experimental system, and that attainment of equilibrium between phases is possible for a wide range of liquid and vapor velocities in reservoirs containing light hydrocarbon fluids. Results of some two-dimensional numerical simulations are also presented. INTRODUCTION This study was undertaken to develop a mathematical model that would simulate transient, two-phase flow of hydrocarbon mixtures in porous media under conditions that result in interphase mass transfer and to test the validity of the assumptions used to set up the model. In addition, the study was designed to determine if production rate influences the recovery of individual hydrocarbon components from reservoirs producing by depletion drive. Two-phase flow in porous media, with interchange of components between the two phases, is important in many petroleum recovery processes. Studiesl-5 conducted within the last 3 years have outlined methods of solving multiphase flow problems incorporating mass transfer. Some of these studies have also indicated the importance of accounting for mass transfer under various producing conditions. An earlier work6 first demonstrated the importance of combining relative permeability data with equilibrium ratios in compositional balance methods. The mathematical model presented in this paper is formulated so that a phase behavior package, as described in previous papers,5,17 is not required as an integral part of the routine employed to solve for the primary dependent variables. The finite difference formulation is designed so that all the primary variables can be solved for simultaneously. This is accomplished by utilizing one basic set of equations. These innovations, which are in contrast to other models2,3,5 but are similar in some respects to the approach used by Taylor,l render the total problem computationally simpler than any of the previously referenced formulations. The mathematical model was developed by combining Darcy&apos;s law with a continuity equation for each hydrocarbon component. The principal assumptions invoked in the formulation were (1) that capillary forces and diffusional effects are negligible, and (2) that thermodynamic equilibrium exists in the reservoir at all times. No assumption as to the type of vaporization process was made in formulating this model. Experimental data were required to complete this study. These were generated by conducting several depletion drive experiments. The experimental apparatus consisted of a sandstone core enclosed in a pressurized casing. The apparatus was designed in such a manner that the core could be charged with a liquid hydrocarbon mixture and depleted at different production rates. The experimental tests were designed to determine the effect of production rate on component recovery. In addition, direct comparison of experimental and mathematically predicted

Jan 1, 1970

By W. A. Koehler, W. L. Eaton, Reynold Q. Shotts, M. E. Hinkle, M. R. Geer, Ralph M. Hunter, H. F. Yancey, Andrew B. Crichton, E. Zimmerman, S. H. Ash

R. Maize and H. P. Greenwald presiding) E. T. POWELL*-I would like to ask either Mr. Ash or Mr. Eaton if they know of any place where the Mine Inspectors&apos; for¬mula has been used that water has flowed from one colliery to the other. W. L. EATON (authors&apos; reply)-We have made considerable study but we have not gotten around to very many of the barrier pillars. I would not say that any or all of them have been designed to the strict figures of this formula. Most of those ex¬amined will not hold back the water that they are supposed to hold back. E. T. POWELL-If the pillar remains ac¬cording to the Mine Inspectors&apos; formula? W. L. EATON-We have not found very many where the provisions were followed. E. T. POWELL-Where the Mine Inspec¬tors&apos; formula has been fully complied with, have there been failures or not? W. L. EATON-I cannot say. Most of these barrier pillars probably were designed in accordance with this formula, but most of them, if they were so designed, are not in that shape now because a large number of them will not hold back the water; they have been reinforced, and they are punc¬tured in various places. Holes have been driven through them to relieve the hydro¬static pressure to avoid a failure. They do not dare to have a failure. In many instances, the barrier is punc¬tured to avoid a failure. In order to mine their coal safely, many companies must pump water from mines that were aban¬doned many years ago. R. MAIZE-That is true, Mr. Eaton, but do you know of any case where a barrier pillar actually failed and flooded an ad¬joining mine when the pillar had been left in accordance with the Mine Inspectors formula?

Jan 1, 1948

By E. P. Pfleider

DIAMOND drill research work was initiated at the School of Mines, University of Minnesota, in late 1949. The Drilling Symposium held in Duluth that spring highlighted the problem of high cost and core recovery and the need for controlled testing. An advisory committee made up of informed representatives of both mining companies and drilling companies was formed to suggest and advise on a program of drill research. A Hy-Mac hydraulic drill unit, see Fig. 1, especially designed for experimental testing, was obtained for this work by the School of Mines through the courtesy of the Carboloy Co. It is an extremely flexible unit, capable of exerting a forward thrust of about 1750 lb and turning at speeds from 650 to 2200 rpm. The feed arrangement is so designed that the advance can be set either at a constant rate or permitted to vary at a fixed pressure, see Fig. 2. The

Jan 1, 1952

By F. V. Lenel

R. P. Seelig.*—Dr. Lenel is to be congratulated on his presentation of a particularly interesting paper describing the use of the powder metallurgy process for the production of magnetic pole pieces. The only thing that might be added is that we have been successful in producing pole . pieces with a narrow hysteresis curve by the use of considerably lower sintering temperatures than the ones used by Dr. Lenel. It is quite possible that this use of lowe- temperatures has considerably widened the field of commercial application for pole pieces made from metal powders. Development work is currently being done on an a.c. application of a sintered iron part. However, I am in full agreement with Dr. Lenel that if eddy currents are an important factor in the application, we cannot substitute sintered material for laminated sheet-metal structures. Mr. Peters&apos; remarks concerning the limitations of machine parts were well taken. The emphasis of the limitations makes it easier to define clearly what we can do and-what the advantages are of machine parts made of metal powders. When I mention metal-powder machine parts, I mean those of relatively high density, although complete elimination of porosity is not possible at this time. The limitations of the field for this type of parts are largely economical. I believe that Mr. Langhammer has made that point very clear. The following questions are very often asked: How large a part can you make? How close can you hold the dimensions ? How fast can a part be produced? In a majority of the cases, it depends on the cost at which the part can be produced. A large variety of shapes and sizes of a number of materials can be formed. However, the main requirement in this field of endeavor is whether this can be done more economically by powder metallurgy than by other manufacturing methods. As a general indication, it may be stated that densities up to 95 per cent of that of rolled material can now be produced commercially in simpler parts. Tolerances of plus or minus 0.001 in. are common, but where special conditions justify, closer tolerances can be held; we are producing a part of which one dimension is held to 0.0003 inch. Finally, as far as maximum size is concerned, technically this would depend on the capacity of the press and furnace equipment available. Actually, we find that the economical limit of powder-metallurgy machine parts is approximately one pound. From there on, each individual case must he studied on its own merits.

Jan 1, 1945

By Lawrence B. Wright, Lester G. Morrell

On the steep slopes of the Kootenays, 15 to 20 miles south of Nelson, B. C., are a number of ore occurrences (Fig. 1). One that has many features of mining and geological interest is the Ymir Yankee Girl Gold Mines Limited. Discovery of this property was made in 1899 at an outcrop on the hillside, some 2500 ft. above the village of Ymir. This proved to be a branch vein 20 ft. long leading to two main veins, the Yankee Girl and the Spur (Fig. 5). The ore pattern as now delimited shows a remarkable increase in ore area with depth below the outcrop. This recent development is of interest particularly in view of the fact that the property was nearly condemned, professionally. Another interesting feature, which has a bearing upon its history, is the persistent excess of tonnage produced from period to period over visible reserves. This is not ascribed to lagging mine development, but to detailed vein characteristics, which we will endeavor to make clear by giving a description of the veins and their surroundings. HISTORY AND PRODUCTION Little interest_was_evidenced-in this-distriet until the building of the railway in 1893 provided easy access and the discovery of the Ymir mine in 1896 attracted attention. As a result, the Ymir Yankee Girl group of claims was staked in October 1899. In 1907, an American syndicate took over the property and subsequently extended the 50-ft. drift and opened the present 400 and 540-ft. levels. In 1908, the Syndicate, without recording any shipments in the meantime, dropped its lease, which was taken up by H. L. Rogers, who bonded the Yankee Girl group. Rogers shipped 2622 tons of ore, mainly from the uppermost stope in the mine, which is reported to have yielded

Jan 1, 1940