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By G. D. Gemmell

Effects of solid-sdutidn alloying with titanium, molybdenum, and tungsten at concentrations up to 10 pct on the strength of pure columbium at elevated temperatures (mainly 2000°F) have been investigated by means of creep-rupture, hot-tensile, and hot-hardness testing and recrystallization studies. ThIS paper presents some results from the initial part of a study of the effects of alloying on the high-temperature strength properties of columbium. The elevated-temperature strength characteristics of pure columbium were first studied. Binary alloys of columbium with titanium, molybdenum, and tungsten containing 1, 5, and 10 pct of the solute elements were chosen on the basis of their high melting points, their known solid solubility in columbium, and results of separate oxidation-resistance studies of columbium alloys. EXPERIMENTAL PROCEDURE All the materials used were of highest purity. A typical analysis of the columbium is shown in Table I. Compositions of the alloys are also given in Table I. To evaluate the strength properties of pure co-lumbium and the alloys at elevated temperatures, creep-rupture, hot-tensile, and hot-hardness testing was done on recrystallized material. To prepare the pure metal and the alloys for these tests, 1- 1b buttons were made in a water-cooled copper crucible, inert atmosphere, tungsten arc furnace. Tapered ingots, 3 in. long, were made from these buttons by a skull-casting technique and these were machined to 1/2 in. diam, swaged to 50 pct reduction (pure columbium at room temperature, alloys at lowest temperature possible without cracking, generally in range 1100" to 1800°F) and heated in vacuum (lo-' mm Hg) for 16 hr at 2550°F for re-crystallization and homogenization. The resulting grain diameter was 0.1 to 0.3 mm. The 10 pct Mo alloy casting was not successfully swaged at temperatures up to 1800°F without cracking and was not included in the test program. Creep-rupture testing was done at constant load in vacuum on cylindrical specimens of 0.16 in. diam, using Instron capsules. The pressure at test temperatures was less than 10-1 mm Hg. Hardneas readings taken on the test specimen before and after testing were used as a check on possible gaseous contamination. Hot tensile tests in vacuum on cylindrical specimens of 0.125 in. diam were also made with Instron equipment at a strain rate of 0.067 min.-l. Hot-hardness measurements were taken with a unit constructed at the Du Pont Experimental Station. The test piece, supported on an alumina anvil, and the molybdenum indenter shaft with sapphire tip is heated in a platinum-wound furnace. The load applied to the pyramid indenter is measured by strain gages attached to a proving ring located outside the hot zone. In the measurements reported here the load was I kg. The tester operates in a vacuum of about 10"5 mm Hg and is capable of temperatures up to 1400°C.

Jan 1, 1960

It is always the case with heavy and cheap materials that the area within which they can be economically used depends upon the cost of transportation, and in those days of poor roads and no mechanical means of haulage on them, coal could only be moved a few miles from the mine by any other means than water. The need of better means of transport to the areas west of the mountains had been urged by Washington and many other leaders, but the first turnpike over the Alleghenies only reached the Ohio River at Wheeling, W. Va. in 1818. The James River and Kanawha road reached the Ohio in 1831, that from Winchester, Va. to Parkersburg in 1838, and the road through the Cumberland Gap was completed in 1797. None of these affected the coal industry excepting indirectly by building up some of the river towns which coal could reach. The inadequacy of roads alone to carry the traffic of the rapidly growing interior communities was demonstrated only a few years after the National Pike was completed, and in the early 1820's several of the states embarked upon the construction of a canal system, which had been under discussion for some years. The Erie Canal was opened in 1825 from Lake Erie to the Hudson River through New York; Pennsylvania, Virginia and Maryland had already started similar projects designed to bring traffic to their principal cities from the interior. The Pennsylvania Canal was started from Columbia, as a railroad extended from Philadelphia to that point, and it followed the Susquehanna and Juniata Rivers to Hollidaysburg; thence to Johnstown, a distance of 36 miles, where it consisted of partly railroad and partly inclined planes, the boats being hauled up, and lowered down the planes; from Johnstown the canal followed the Conemaugh, Kiskiminitas and Allegheny Rivers to Pittsburgh, 104 miles. Boats first reached Pittsburgh by this route in 1834. The Chesapeake and Potomac Canal followed the Potomac River from a point above Alexandria above the falls, to Cumberland. This canal was chartered in the eighteenth century and a portion of it was used by traffic in 1800. It was too small to be of much use and was abandoned, and later after many legal and financial vicissitudes was completed to Cumberland, traffic from there starting late in 1850. This date, however, was long after the Baltimore and Ohio Railroad had been completed to

Jan 1, 1942

By Edward Adarns Richardson

As developed up to the end of the Great War, an airplane was essentially a mechanism of wood and fabric, joined and held together by metal fittings and fastening. The engine and accessories, wire for wheel spokes and other tension members, and the occasional use of metal for inter-plane struts and the shafts of surface controls required some metal, but essentially it was a wood and fabric structure. Attempts had been made to use metal for other purposes, such as struts in the drag-trussing of wing panels and for short interplane struts, and Junkers had produced an airplane of iron in 1915. By 1917 he was using steel tubes and duralumin sheets, securing noteworthy advantages aerodynamically and from the standpoint of weight and upkeep. He was a pioneer along lines in which progress is still being made. Principles of Airplane Construction The loaded weight of airplanes ranges from 500 lb. for the light plane of which we heard so much a short time ago, to about 40,000 Ib. The great majority of planes range from 2000 to 10,000 Ib. Of this weight from 15 to 30 per cent. is for the dividend-earning load. This percentage is so low that every per cent. saved on the rest of the weight increases the pay load from 3 to 6 per cent,. The economic value of every pound that can be saved in designing or constructing a plane is sufficiently great to warrant spending money on refined methods of structural analysis, materials of superior strength properties for a given weight, methods of manufacture which may make possible the use of refinements in structural design, and the like, to an extent unknown heretofore. The weight of the airplane, without fuel, oil and crew, and pay load, ranges from 50 to 65 per cent. of the total weight loaded for planes suitable for commercial use. It is doubtful if the structural weight will ever be brought down to as low as 40 per cent. for commercial planes. The airplane may be roughly divided into: (1) Power plant, which includes engines, radiators, cooling water, oil and fuel tanks, piping, propellers, engine-starting systems, pumps, super-

By G. W. Healy, D. C. Hilty

MAJOR considerations in the production of stainless steel are the utilization of stainless steel scrap and the recovery of chromium and other metallic values from the initial furnace charge. The decarburization of a bath of molten chromium steel with gaseous oxygen is usually accompanied by a considerable amount of metallic oxidation. Since recovery of this metal from the slag may require substantial expenditures of time and materials for slag reduction, holding metallic oxidation to the minimum consistent with good operating practice is generally desirable. The important role of temperature in minimizing metallic oxidation is illustrated by Fig. 1, taken from the results of Hilty, Healy, and Crafts,' who established the quantitative relations connecting the amounts of chromium, manganese, and iron oxidized during the oxidizing period of chromium steel heats with the composition of the initial charge and the temperature and composition of the molten bath after oxidation. Higher temperatures after the oxygen blow result in lower metallic oxidation. Although high temperatures are desirable for minimizing metallic oxidation, practical operating considerations limit the degree to which they can be employed. Excessively high temperatures or prolonged operation at moderately high temperatures may cause serious damage to the furnace refractories, so that a compromise must be effected. The problem, therefore, is one of controlling the oxidizing period of chromium steel heats to the shortest time at the highest practical temperature. The most effective tool the steel melter has for attaining high temperature while decarburizing a chromium steel heat is now commonly considered to be the oxygen lance with an adequate supply of gaseous oxygen. In order for the tool to be effective, however, the heat resulting from the oxidation of carbon, chromium, silicon, manganese, and iron in the bath must exceed the heat losses from the furnace. General recognition, of this principle has stimulated a trend toward faster injection of oxygen. For example, Pachaly2 proposed a high temperature at the start of the oxygen blow or a high rate of oxygen input as a means of obtaining the desired carbon level with high chromium recovery. On the other hand, limited understanding of the specific effects of oxygen input rate has hampered development of optimum practices. As part of a broad study of the metallurgy of chromium steel melting, therefore, the Linde Air Products Co. and the Electro Metallurgical Co. at their Metals Research Labo-ratories have evaluated the heat-balance during the oxidizing period in terms of oxygen input rate. The evaluation has then been related to factors such as temperature increase, metallic oxidation, oxygen Utilization, etc., and extrapolated to include a wide

Jan 1, 1958

By E. C. Bitzer

THE primary object of the work described in the following pages was to simplify the equipment in the separating circuit of the heavy-media process by substituting a spiral classifier for the separatory cone. Mechanical considerations were the leading attraction and the best that was hoped for on metallurgical performance was that the new vessel would give results equal to those obtained by conventional equipment. Tests have demonstrated in commercial operation on iron ore that the mechanical advantages of the spiral separator are about as predicted; also, the metallurgical performance is superior to the cone on the ores treated. Treatment of iron ore involves the separation of two products: a concentrate that sinks and a float product that contains true float material plus a controlled division of interfering middling. The middling material is heavier than the average specific gravity of the separating medium. Recent work with the spiral separator on Tri-State zinc ore showed that the middling material had to be recovered as concentrate because this fraction contained the bulk of the-zinc in the ore. It has been demonstrated that it is possible to make three products with the new separator on an ore such as this: a float tailing, a float middling, and a high grade heavy sink product. It appears from this last work that the new separator has definite mechanica1 and metallurgical advantages over any type of separating cone for treating feed that contains large amounts of material of a specific gravity close to that of the separating medium. However, either type of separator should perform equally well, metallurgically, on feed that is free of middlings. Each series of experiments with the spiral separator as required additional work to fully develop the possibilities of the machine. For this reason the paper is divided into chronological parts. History of Development A drag-type classifier was first proposed as a substitute for the cone separator by Butler Brothers technicians during the initial tests with galena medium at Crosby, Minn., in 1937. The desire for finding a substitute for the cone arose from trouble with interfering middlings and certain operating disadvantages of the cone. The possibility of using a spiral classifier was also suggested at this time by Emmett Butler and C. J. Abrams. However, inability to satisfactorily recover fine galena, which was used as a medium, terminated all development work at Crosby. During the winter of 1937--1938 investigation started on magnetic medium with concurrent s development of the inverted or closed- top cone, which was found necessary to eliminate iron-ore middlings with the float product. About

Jan 1, 1947

By J. H. Lightfoot, Stuart E. Buckley

Deep drilling has led to the development of numerous pools which yield products consisting predominantly of natural gas accompanied by high-gravity water-white or slightly straw-colored liquid. Yields of this "condensate" or "distillate," as it is commonly called, vary from traces to over a hundred barrels per million cubic feet of gas. The fact that this liquid exists in the reservoir as an integral part of the gas phase and is formed by condensation attending simultaneous reduction of pressure and temperature after its entry into the well was apparently first recognized about 1932.l The nature of the physical phenomena involved in this condensation was clarified for the petroleum industry in 1933 by a report by Sage, Schaafsma, and Lacey2 of the results of an experimental investigation of the behavior of mixtures of methane and propane. Search of the literature has revealed that the condensation of liquid from gaseous mixtures by isothermal pressure reduction is not a new discovery. Kuenen was led by theoretical considerations to expect such a phenomenon, and in 1892 reported3 the results of experimental verification of his deductions. This was followed by a considerable amount of work on the phase relations of mixtures by Kuenen 4,5,6 and by 0thers,7,8 mostly in European universities. Since 1930 investigators in this country have reported experimental data on the properties and behavior of a number of hydrocarbon systems."' It is now generally known that in the presence of natural gas the solubility in the gas phase of the heavier and normally liquid hydrocarbons increases rapidly with increasing pressure above 500 to 1000 Ib. per sq. in. Thus, at pressures of 2500 Ib. per sq. in. or higher a gas may contain appreciable quantities of hydrocarbons with normal boiling points as high as 6o0°F., which in turn may be condensed from the gas phase by the reduction of their solubility therein attending pressure reduc-tion. The combined effects of pressure and temperature on condensation and vaporiza-tioi of mixtures are most readily visualized by the study of phase diagrams. Since the construction, application, and interpreta-tion of such diagrams have been described fully in readily available literature, 18-20 this paper will not review the theoretical aspects of this subject. While the behavior of gas-distillate sys tems is now clearly understood, at least in a qualitative way, most of the published work deals with the results of laboratory studies of binary systems or of synthetic mixtures of hydrocarbons, and although several systematic investigations of the effects of separator pressure and temperature on the yields of liquid product from gas-distillate wells have been made21,12z it appears that in all cases the limitations have precluded the construction of even approximately complete phase diagrams for naturally occurring systems. There has 2

Jan 1, 1941

By A. D. Hodges

The great mining region of Peru is a mountainous belt of country, running nearly the whole length of the republic, and comprising the two grand ranges of the Andes with the elevated table-lands between them. On the east of this belt are the extensive plains and fertile valleys of the Amazon and its tributaries. On the west is a narrow strip of coast 20 to 50 miles wide, for the most part a sandy desert, but producing abundant crops where irrigated ; and here are found petroleum (Department of Piura), salt (at Huacho and elsewhere), nitrate of soda in enormous amounts at the south, silver in a few localities (Province of Tarapaca), copper and other mineral products. The Western Cordillera, running nearly parallel with the shoreline, rises like a wall on the eastern side of the coast-belt, with passes from 15,000 to 18,000 feet high and peaks attaining 18,000 to 20,000 feet. Further east, at a varying distance, is the Eastern Cordillera, composed of broken mountain ranges which, considered as one group, have a general parallelism with the western chain, but individually vary greatly in direction, sometimes running nearly east and west, in places projecting out into the Amazonian lands, or here and there curving around to unite with the western ridge, and with this enclosing immense inter-alpine plains. These general features are indicated in Fig. 1. The surface of these plains is uneven and traversed by lower ranges of hills which surround large lakes, or rolling pampas, or fertile valleys; and through many of these last run rivers of considerable size. The whole country has a high altitude (averaging up to 15,000 or 16,000 feet), and slopes gradually north and east towards the Amazon, into which drain all its waters. Its bounding mountain chains are scored on all sides by narrow, picturesque and pre-

Jan 1, 1888

By S. W. Zanolli

The history of labor relations in the coal industry of the United States is a study of its collective bargaining. This study of collective bargaining is largely the history of the United Mine Workers of America and its contractual relations with the various coal mining employers who have produced this country's coal over the years under a free enterprise system. There have been other unions in the picture from time to time and some coal miners have mined coal without representation by any union. Even today some 25% of the nation's coal is produced outside of the collective bargaining relationship with the UMWA. However, more than 100,000 coal mine wage employees - well over 75% of the total in the industry - are covered by labor agreements negotiated for them by the UMWA. Practically all of these work in bituminous mines.

Jan 12, 1972

By C. A. Pierce

UNDERGROUND operations of the United States Potash Co. at its mine near Carlsbad, N.M., have been continuous since the property was opened about five years ago. Approximately one million tons of potash has been mined and two shafts have been sunk, each to a depth of about 1000 ft. Outstanding in the company's operations is the fact that not a single blasting accident has occurred during the aforesaid period. The purpose of this paper is to describe the blasting practice that has made possible the achievement of this accident-prevention record. The mining method employed in extracting the thick horizontal bed of potash may be described as a double-entry room-and-pillar system. Mine development is kept well in advance of extraction operations, and a three years' supply of ore, at least, is always available. Limits of the orebody have not been determined, and in the present system of mining headings are advanced by a "shortwall" method. This was the first potash ore bed developed in the United States. The nature of the deposit, therefore, was unknown, and it was deemed expedient to outline a conservative mining policy. Later, when more is known about the deposit and certain control ascertained, a "longwall" panel retreating method may be found advisable. The necessity for a domestic supply of potash became a national issue previous to and during the World War. The United States Govern-ment came to realize that this country should not be dependent upon foreign sources of potash, and began extensive explorations in many parts of the country, seeking an orebody that would meet the exacting require-ments of the domestic market. The Department of Interior, through the Geological Survey and Bureau of Mines, made every effort to determine the location of potash deposits and encouraged their exploitation by private capital. Through the combined efforts of the Department of Interior and private industry, the deposit now being worked by the United States Potash Co. was discovered and brought into production.

Jan 1, 1936

By C. P. Watson, R. E. Collom

Various chapters already written in the history of development of the North Dome of Kettleman Hills are monotonoysly identical in the one underlying' theme of conservation of oil and gas. Discovered on Oct. 4, 1928, by Milham Exploration Co. with its wildcat Elliot No. 1, the field has been subjected to practically every modern form of production restraint in the name of conservation. The record thus far developed shows that conservation was had for a time, at a price; and that unitiza-tion must be blessed by single ownership or 100 per cent participation to be effective. In fact, incomplete unitization places a heavy handicap upon its participants in the competitive development that follows. Shut-in Agreement of July 25, 1929 Not long after discovery at Kettleman but after the Continental Oil Co. and the Standard Oil Co. had completed several producing wells in the discovery group, came the so-called Shut-in Agreement negotiated at the instance of the Department of the Interior. This agreement became effective July 25, 1929. The fundamental purpose of the agreement was to prevent bringing on production of some 30 wells then being drilled and forestall a flood of Kettleman oil on the market. A cooperative scheme was developed whereby wells in the discovery group would continue to produce. Two of them could not be shut in. Drilling wells would be completed to a water shutoff in top of Temblor and operations suspended. Producing wells would contribute the value of 10 to 25 per cent of their production to the owners of suspended qualifying wells. The percentage rate of drainage contribution was left to a committee or umpire. Some acreage was not placed under the agreement. This same acreage later did not come into the Kettleman Unit Agreement. Several wells on this acreage did not contribute to the drainage fund. The total amount of oil produced during the 17 months of the shut-in agreement, by Milham, Continental and Standard from wells in the discovery group, was 5,297,262.22 bbl. The total amount paid out in "drainage" contributions was $2,046,048.18, representing sales value of 1,266,044.06 bbl. of oil.

Jan 1, 1937

By George F. Weaton, Eugene P. Pfleider

13.4-1. History. During the past ten years the mining and production of iron ores has been through a revolution. From 1939 through 1948, which included World War II, 561,000,000 tons of iron ore was mined and shipped from Minnesota's Mesabi Range to the blast furnaces of the United States for the production of iron and steel products (20, 28, 29). The iron mining industry, anticipating the exhaustion of this highly productive source of raw material, instigated a worldwide search for new sources of iron ores. This search was highly successful, both as to quantity and quality. Venezuela (38), Canada (17, 28, 42), Peru (19, 23, 50, 52, 54, 56) Chile, (1, 66, 75), Brazil, and Liberia were among the countries where enormous deposits of high quality iron ores were discovered. The exploitation of these deposits took away the monopoly held by the Lake Superior region for so many years and created a highly competitive market for high quality natural iron ores. 13.4-2. Exploration and Development Practices. SPECIFIC TO IRON MIN- ING. American industries are motivated to continue exploration because new ore discoveries often lead to an improved competitive position with respect to raw material supply. Exploration techniques have advanced rapidly in recent years, to a degree that potentially important iron ore reserves, stratigically located, may now be detectable by application of a combination of refined and diversified geophysical exploration methods. Since the days of the dip needle, iron ore people have placed greatest reliance on the magnetometer. Its successive stages of development progressed from the balance and the torsion type to the fluxgate, and then to the "sophisticated" magnetometers-conceived and developed in th field of atomic physics. By far the greatest advancement in magnetometer prospecting was made when the self-orienting fluxgate magnetometer took to the air. This was not a new development, but it was a breakthrough in reconnaissance investi-

Jan 1, 1968

By D. G. F. Hedley, D. F. Coates, K. Barron

INTRODUCTION Preceding papers presented in this symposium have considered the influence of various parameters, such as geologic structure, groundwater, etc., on the stability of rock slopes and have given some analyses and guide lines for slope design. To carry out such analyses it is necessary to put numbers to these parameters; where possible, this is best done on the basis of in- situ observation and measurement. Since none of the design analyses can be considered exact and since conditions vary during excavation, it is also desirable to monitor the behaviour of the slopes as the excavation proceeds. In this manner a feedback of information on the actual excavation conditions can allow a continuous reassessment of the design parameters to be made and can give early warning of incipient failures. The purpose of instrumenting rock slopes is thus to provide information which fits into one of two categories: (a) To give basic data to assist on-site assessment and design of the rock excavation. (b) To provide data for the control and assessment of safety during excavation. The purpose of this paper is to review briefly some of the instruments and measuring techniques available for gathering this data and to indicate where such data may prove useful. This is not a comprehensive review of all available instrumentation but, rather, is a survey of some of the instruments and techniques with which the authors have had some experience and which have proven useful. STRUCTURAL ASSESSMENT Whilst most structural assessment of a site is done on the basis of geologic mapping and core examination, there exists some instrumentation which can, in particular circumstances, assist in this assessment. Seismic instruments can be used to determine the geometry of formations and to give an indication of the relative competency of rocks. These instruments operate using seismic reflection or refraction techniques and, although mainly confined to shallow sub-surface exploration, can be useful in distinguishing between soil/ bedrock contacts and, in some cases, the extent of weathered surface rock.

Jan 1, 1971

By David B. Burrows, Rlkl Kobayashi, Norman L. Carr

The viscosity of hydrocarbon mixtures, whether in the gas or liquid phase, is a function of pressure, temperature, and phase composition. This paper presents methods for the prediction of the viscosity of the gas or less dense fluid phase over the practical range of pressure, temperature, and phase compositions encountered in surface and subsurface petroleum production operations. The correlation necessary to predict the effect of pressure on viscosities is presented in Part I. Serious discrepancies in high pressure gas viscosity data in the literature are discussed. The application of the correlation to predict absolute viscosities is discussed in Part 11. Auxiliary correlations are presented to enable calculations of viscosities from a knowledge of the pressure, temperature, and gravity of the gas phase. INTRODUCTION A knowledge of the viscosity of hydrocarbon fluids is needed to study the dynamical or flow behavior of these mixtures through pipes, porous media, or more generally wherever transport of momentum occurs in fluid motion. Since flow is predominantly in the laminar region in petroleum reservoirs, the influence of fluid viscosity on this flow is especially important. As early as 1894, Onnes1 and Onnes and de Haas' noted that the viscosities of homologs under corresponding states could be correlated. The theorem of corresponding states has been further developed and applied to the viscosity of pure, nonpolar gases under pressure by Comings, Mayland, and Egly.3 It was demonstrated that the viscosity ratio could be expressed rather closely as a function of reduced pressures and temperatures, 1.e.: µ/µ1 = f( TR2 PR) ........(1) temperature, absolute units where: TR =------------------------------ ------ critical temperature. absolute units _pressure, absolute units critical pressure, absolute units µ = viscosity of gas at reduced temperature TR and reduced pressure PR µ1 =. viscosity of gas at atmospheric pressure and at temperature TR Serious discrepancies in the viscosity of pure hydrocarbon gases at high pressures have been called to Our attention by Comings, and and Egly. They made a careful analysis of the following methods commonly used to measure gas viscosities: 1. Oscillating disc viscometer4,5 2. Rolling ball viscometer6,7 3. Capillary tube viscometer12 On the basis of their analysis of the problem and their experimental data on the viscosities of methane, ethylene, carbon dioxide, and propane, they preferentially selected data obtained by the capillary tube viscometer to develop their viscosity correlation. Since then a need has existed to verify the experimental technique of Comings, Mayland, and Egly for the determination of viscosities at high pressure; to extend the data to mixtures of hydrocarbons; and to extend the range of their correlation to include higher pressures. Using the correlation procedure of Comings, May-land, and Egly, the prediction of gas viscosities is resolved into the correlation of the effect of pressure, temperature, and composition on the viscosity of hydrocarbons and their mixtures and the prediction of viscosities of mixtures of hydrocarbons and other natural gas components at one atmosphere pressure.

Jan 1, 1955

By W. Rostoker

The process of diffusion alloying of mixed powders offers attractive possibilities both commercially and experimentally. It avoids the fabrication difficulties arising from high alloy contents. Indeed, the process is facilitated by larger alloy additions. The direct formation of the part or test piece and the opportunlity to perform machining operations under more favorable conditions are of no small importance. However, it is necessary to make only brief mention of the interesting features. As yet there have been few attempts to study this process in detail and to carry it to completion, if such is possible. It was intended not only to measure the intermediate and optimum magnetic properties of sintered alloys but to use magnetic testing itself as a means of following the progress of alloying under various condi-tions. Having established that alloys could be successfully synthesized by this tech. nique, the opportunity was taken to study the magnetic properties of several alloys of iron and silicon which had hitherto been too difficult to prepare in suitable test piece form. While avoiding some of the difficulties inherent in the fabrication of alloys by orthodox methods, the diffusion alloying process introduces a few of its own. The first of these is the evaluation of the approach to homogenization. In recent years some notable contributions have been made to this question, but considerable uncertainty remains in its definition and evaluation. This work has concerned itself with further study of this problem and it is hoped that more light has been shed on it. The second of these difficulties arises from the presence of porosity. It is inevitable that in the consolidation of a loose bulk of powder, there should remain some voids unless extremely high pressures are repeatedly applied. It was therefore of importance to investigate their effect on magnetic properties. Recently this effect has been studied and certain predictions made of its behavior. It is believed that the experimental results presented here provide a sound substantiation of the theoretical treatment. The attempt has been made to synthesize five alloys of the iron-silicon system and three each of the iron-nickel and iron-cobalt systems. A series of experiments was also conducted on some of these alloys to test their susceptibility to heat treatment. Some unfortunate experiences have provided opportunity to report data on the deleterious effects of nitrogen on magnetic properties when present as a a in protective atmospheres. MateRIALS, PREPARATION OF SAMPLES and Testing The purest materials available were em. ployed for this work. A specially purified,

Jan 1, 1949

By B. N. Bose, M. F. Hawk

SINCE Davenport and Bain' introduced the isothermal transformation technique for the study of austenite decomposition in steels, a new field of investigation has opened up. Extensive research has been carried out on many different steels, but relatively little work has been done on eutectoid transformations in analogous alloy systems. The researches of Smith and Lindlief,² Mack,³ and Klier and Grymko²0 on the beta-phase transformation in copper-aluminum alloys, of Hibbard, Eichelrnan, and Saunders4 and Smith5 on the kappa-phase transformation in copper-silicon alloys, of Chaudron and Forester6 on the decomposition of "FeO," and of Wasserman7 on similarities between the iron-carbon, copper-aluminum, copper-tin, and copper-beryllium systems essentially comprise the field. The iron-nitrogen system, in view of its remarkable similarity to the iron-carbon system, is particularly attractive for the study of eutectoid decomposition. The present investigation is concerned with the study of isothermal transformation, proceeding by the familiar nucleation and growth processes, and of martensitic transformation characteristics of pure iron-nitrogen alloys. The kinetics of transformation and the morphology of the transformation products have been investigated, for these must be the factors determining the properties and behavior of the final product. The Iron-Nitrogen System he binary iron-nitrogen phase diagram has been a matter of considerable disagreement among vari01.1s investigators. However, the phase diagram according to Eisenhut and Kaupp8 and Lehrer10 is now considered essentially correct as reproduced in fig. 1. The important values, 2.35 pct nitrogen and 591°C, for the co-ordinates of the eutectoid point (obtained from this diagram and used in the re- search to be described) were confirmed in a concurrent study of Paranjpe, Cohen, Bever and Floe." The eutectoid decomposition involves the transformation of the ? face-centered cubic interstitial solid solution of nitrogen in iron to the a body-centered cubic interstitial solid solution of nitrogen in iron and the ?' nitride of iron. This nitride is essentially the compound Fe,N; it also possesses a face-centered cubic lattice but a considerably larger one than the ?; the nitrogen atoms in ?' are arranged in an ordered way in the centers of the unit cubes.8,10,11 A martensitic structure has also been reported8,12 in iron-nitrogen alloys and was studied in the research to be described here. Materials and Methods The specimens used in this investigation were prepared by nitriding "pure" iron. This iron was supplied by the Westinghouse Research Laboratories and is the product bearing their trade name "Puron"; it contains about 0.04 wt pct total impurities, the major portion of which is oxygen. Specimens were ribbons several inches long, a tenth of an inch wide, and 0.125 mm thick; this was the

Jan 1, 1951

By Enid C. Plante

THIS paper deals with the flotation of the mineral fluorite (calcium fluoride) and of two associated gangue minerals, calcite and quartz. The aim of the investigation was to produce "acid-grade" fluorite, which must contain less than one per cent of silica. Several reagents are used successfully in practice for floating fluorite from its ores. Oleic acid is the most widely used collector, usually at temperatures above 60°C, with sodium silicate as a dispersant for quartz and quebracho or tannin to depress calcite. Sulphides (e.g., galena) are often removed first by xanthate flotation. Many investigators23 report results in which more than 80 pct of the fluorite is recovered in a concentrate assaying 96 pct or more of fluorite and less than I pct of silica. This investigation was undertaken with the intention of floating the gangue, which is the minor constituent of the ore, from the fluorite. Hence emphasis was first placed on the cationic compounds that float quartz. No satisfactory separations were obtained in this way, and other reagents were investigated to discover whether these were more effective than oleic acid in floating fluorite from quartz in the usual way. The first part of the paper describes experiments with several long-chain collectors available commercially. Most of this work has been by captive-bubble and cylinder flotation tests, with some batch tests in a flotation machine. The second part describes the use of sodium cetyl sulphate as a collector for fluorite and includes laboratory tests and extension of the work to batch tests in the flotation machine. A method for determining the adsorption of sodium cetyl sulphate on fluorite has been developed and is described. Theory of Collection by Paraffin-chain Salts It may be assumed that these compounds are adsorbed at the mineral surface in one or more of three ways outlined by Kolthoff :12 I. Exchange adsorption between lattice ions in the mineral surface and collector ions in solution. Closely related is adsorption by the collecting mechanism postulated by Taggart,17 in which there is metathesis between the collector and the mineral cation or anion. 2. Exchange adsorption between adsorbed gegen ions (p. 67, ref. 19) and collector ions in solution. 3. Adsorption of nonelectrolytes (polarnonpolar) without displacement of adsorbed ions. With cationic collectors, inorganic cations in the solution (e.g., hydrogen ion) compete with the collector ions and therefore act as depressants, while inorganic anions have the same effect with anionic collectors. From this follows the general conclusion that ions of the same charge as

Jan 1, 1947

By Philip D. Wilson

The mines of the Calumet & Arizona Mining Co. are situated in the Warren Mining District, Cochise County, Arizona, between Bisbee and Warren and adjoin those of the Copper Queen Consolidated Mining Co. and the Shattuck Arizona Copper Co. Paleozoic 1imestones.of considerable thickness have been intruded by granite porphyry. A great stock of the intrusive outcrops boldly near the city of Bisbee and is known as Sacramento Hill. From this central core the porphyry has tongued out into the limestone for many thousands of feet as dikes and sills of irregular shape and variable dimensions. Churn drilling has recently developed a large tonnage of secondarily enriched copper ore in the main porphyry mass of Sacramento Hill. While some ore has been found in porphyry in other parts of the district, it is relatively unimportant compared with that which occurs in the Paleozoic limestone as irregular lenses replacing favorable beds near porphyry contacts or associated with well-marked fracture zones often many hundreds of feet away from the intrusive. In a zone extending from Sacramento Hill for a distance of from 1,500 to 3,000 ft., the limestone has been extensively metamorphosed and in this contact metamorphic zone the ore occurs through a known vertical thickness of upward of 900 ft. and individual orebodies often show extension in a vertical direction of over 200 ft. At a greater distance from the intrusive stock, the ore occurs as lenses of greater horizontal than vertical dimensions with an average thickness of approximately 30 ft. An exception to this rule is found in the occasional steeply dipping mineralized fractures, almost true tabular veins, which are found long distances a way from the zone of contact metamorphism. The copper was probably introduced during or slightly later than the porphyry intrusion in the form of chalcopyrite and bornite. These primary copper minerals are always associated with pyrite and often occur as rich lenses in a huge mass or shell of pyrite carrying an insignificant percentage of copper. In many instances the copper-bearing solutions were preceded by siliceous solutions and these latter, often persisting during the period of mineralization, have thoroughly indurated the ore-

Jan 1, 1917

By J. W. Bolton, S. A. Weigand

Production of sound bronze castings is a matter of great practical interest to users and manufacturers of high-grade non-ferrous engineering specialties. Although there has been much excellent research in this field, there still remains some confusion regarding the fundamental principles underlying production of really sound bronze. The literature of the past 20 years on this subject indicates that the prevailing opinion of metallurgists and foundrymen has been that unsoundness in bronze is due generally to oxidation. The following references are typical. Review of Literature Carpenter and Edwards1 state that when gun metal is melted the alloy dissolves gas, the amount increasing with rise in temperature and duration of the melting. The solubility of the gas diminishes during the fall in temperature and it escapes through the liquid metal. At the moment of incipient solidification there is an evolution of gas. Sperry2 says that by using charcoal a reducing atmosphere is supplied whereby oxidation is prevented, and this also prevents gases from coming in contact with the metal. Logan3 says that many of the troubles that occur in non-ferrous castings are the direct result of one thing—oxidized material. He mentions how readily copper absorbs oxygen when molten, but does not mention the harmful effects of reducing conditions as observed in overpoled copper. Guillemin and Delachana14 investigated the gases occluded in bronze and found that the better bronzes contained mostly hydrogen while the poorer ones had a larger proportion of carbon monoxide and carbon dioxide.

Jan 1, 1929

By M. D. Cooper

For the purpose of obtaining some first-hand data in regard to the shooting down of coal in bituminous mines, it was the writer's good fortune to be employed as a shot-firer for almost one year. In all, 6020 shots were fired by him during this period. All of the work was done in what is known as the South Main section of the No. 2 Mine of the Ellsworth Collieries Co., Ellsworth, Pa., a subsidiary of the Lackawanna Steel Go. Position of Shot-firing in the Cycle of Operations The established practice of the Ellsworth Collieries Co. calls first for the undercutting of the coal by electric chain machines across the face of the entry or room. This is followed by replacing any posts removed by the machine-runners, or the setting of new posts or timber, as may be required. After this has been done the machine cuttings are loaded into cars. Then the coal is spragged, and a shot hole drilled to the depth of the undercut. Next in order, the shot-firer loads the hole and fires the charge. The working place is then cleaned up, timbered if necessary, the sides and face squared up, and loose material taken down. The face is again ready to be undercut. Materials Used Permissible explosives were used exclusively in blasting coal. These were Carbonite No. 2, a nitroglyccrine explosive; and three different makes of ammonium nitrate explosives, Tunnelite, Red H, and Mine-ite 5-D. The last-named was used during the greater part of the period. It is interesting to note that even at the beginning of this work, the gases resulting from the explosions of the charges caused no especial distress on. the shot-firer's part and this continued to be the case except on the occasions when a change was made from one class of explosive to another.

Jan 1, 1918

By L. G. Austin, P. T. Luckie, R. R. Klimpel, R. S. C. Rogers

1. INTRODUCTION The Bond method(1.2) for sizing tumbling ball mills has been used successfully for many years. The primary purpose of the Bond calculation is to predict the mill size and mill power to give a desired capacity (Q tph) from a wet overflow ball mill in normal closed circuit operated with a circulation ratio of 2.5. The input to the calculation is the make-up feed size characterized by the 80%-passing size in micrometers (xG), the desired circuit product size characterized by the 80%-passing size (xQ), and an empirical grindability number (the standard Bond Work Index) determined by a standard test. A series of empirical correcting factors(2) are used to convert the results to open-circuit or dry grinding in grate discharge mills. The Bond method has two major engineering advantages: (i) it is very simple; (ii) experience has shown that it works for many circumstances, as a reasonable approximation, because it is based on direct conversion of test data to results measured on industrial mills. There are four main disadvantages of the Bond method. First, there will be a range of error for any specific mill and material and set of operating conditions because the method does not explicitly include several variables which are obviously important: (i) recycle ratio and classifier efficiency (ii) mixture of ball sizes in the mill (iii) variations of residence time distributions with mill geometry and slurry density (iv) lifter design (v) slurry rheology (vi) different underfilling or overfilling of the mill as flow rate is changed. Second, the Bond method explicitly assumes that specific grinding energy E is not a function of ball load, whereas industrial practice and laboratory tests(3) show that the specific grinding energy (to go from a specified feed to a specified product) is less for lower ball loadings than the ball loading for maximum mill capacity. Third, the method uses only the 80% passing size of circuit feed and product to characterize the size distributions, whereas mill capacity in general must depend on the shape of the feed size distribution and the product size distribution. The prime example of this is the use of the reverse closed circuit which removes some fraction of the make-up feed before it is

Jan 1, 1982