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By Monte J. Pool, Rudolph Speiser, George R. St. Pierre, William T. Ebihara

Standard free energies of formation of WO,, W O W20058 and WO3from oxygen and the lower oxide or tungsten have been determined in the tempel-ature range of 700° to 1220°C. A tentative W-O phase diagmm is presented based on the evidence that the oxide phases, "W18O49" and "W20058", are unstable at l~atm total pressure, below 585° and 485°C:, respectively. A HE need for a complete quantitative treatment of the phase equilibria of the W-O system has been establishedby metallurgists during the past few years. In an attempt to improve the endurance of tungsten exposed to oxidizing atmospheres at high temperatures, many research groups have studied the kinetics of tungsten oxidation. The reverse process, the reduction of the tungsten oxides to metal, has also been investigated to some extent. Regardless of the particular interest, metal to oxide or oxide to metal, a knowledge of the phase equilibria of the W-O system is required to properly interpret all of the kinetic observations. It should be possible to state the stable phases of the W-O system at any given values of the chemical potential of oxygen and the temperature.

Jan 1, 1962

By Robert W. Zimmerman

POROUS SOLID COMPRESSIBILITIES There are four different compressibilities associated with porous solids, each relating the fractional change in either bulk volume or pore volume with the change in either pore pressure or confining pressure. These will be referred to as Cbc, Cbp, Cpc, and Cpp, with the first subscript denoting the relevant volume, and the second subscript denoting the relevant pressure. They are defined as: [ ] Note that minus signs are included in two of the definitions so that each of the compressibilities will always have a positive value. In general, each compressibility depends on the elastic moduli of the matrix material, the porosity, and the exact geometry of the pores. Taking the latter factor into account calls for separate analysis for each different pore shape, which of course can only be attempted for a few relatively simple cases. But lower bounds for each of the four compressibilities can be found, independant of pore structure, in terms of only the porosity (0) and the elastic moduli of the matrix material (any pair chosen from K, E, G and V). The first step is to find relationships between the four compressibilities, starting with the following observation: If a porous solid made of a linear elastic, isotropic and homogeneous matrix material is subjected to uniform hydrostatic pressure of magnitude P on its external and all of its internal (pore) surfaces, the state of stress in the solid will be exactly the same as that which would occur

Jan 1, 1982

By D. D. Pollock

The resistivity, temperature coefficient of resistance, and absolute thermoelectric properties of some binary terminal solid solutions of silver were determined. Equations are given which permit the calculation of these properties. CONSIDERABLE work has been done on the constitution and electrical conductivity of binary alloys of silver.1-l2 Some of these alloy studies are apparently complicated by doubtful chemical analyses. In some cases the limits of solid solubility are questionable. Those references which present electrical properties of binary silver alloys usually give just one particular set of characteristics such as conductivity (or resistivity). As a means of checking and extending this earlier work, an investigation was undertaken to describe and calculate the resistivity, temperature coefficient of resistance, and thermoelectric power of binary terminal solid solutions of silver. PREPARATION OF ALLOYS All of the alloys were made with silver containing less than 0.014 pet (by weight) of impurities. These materials were carefully weighed out into 225-g heats and melted in a high-frequency induction furnace. The indium, tin, and antimony systems were melted in Al2O3 crucibles, under a boric anhydride cover, and poured into split graphite finger molds. The aluminum, germanium, arsenic, lead, and bismuth alloys were melted in machined graphite crucibles, and they were also covered with boric anhydride and poured into split graphite finger molds. The alloys containing magnesium and manganese

Jan 1, 1964

By Albert D. Brokaw

The accompanying charts are presented to extend and improve a chart published under the title "A Chart to Provide Approximate Correction for Temperature and Deviation from Boyle's Law."' The applicability of this earlier chart was limited by the fact that it was based on the work of Burke and Keyes² and Kvalnes and Gaddy3 whose experiments were conducted with pure methane, the adjustments suggested for natural gases of higher specific gravity were unsatisfactory except within limited ranges of temperatures and pressures, and precise interpolation was difficult. The extensive work of G. G. Brown, D. L. Katz and their associates on the heavier natural gases has provided better bases for the needed corrections, and the present charts. which are based largely on their work, are intended to simplify the computations involved. The design of the charts has been changed by plotting temperatures as a function of pressure and correction factor, on a semilogarithmic or "ratio" grid, which gives fairly even spacing of the graphs and simplifies interpolation. Charts have been prepared for natural gas with specific gravities of .60, .65, .70, .75 and .80. The standard computation for use in estimating the quantity of gas in a reservoir may be expressed as follows: _ PA X 520 X VR ZT where: Q is the volume of gas at 60°F and one atmosphere pressure PA is the absolute formation pressure in atmospheres

Jan 1, 1949

By Thomas M. Tharp

INTRODUCTION Attempts to analyze the stability of slopes, foundations and underground openings in discontinuously jointed rock have generally assumed full joint continuity or ignored the role of stress concentration at the tips of discontinuous joints. The most common approach in rock slopes is to consider a failure plane consisting of coplanar, but discontinuous joints separated by intact rock. The intact rock is assumed to fail in shear as a Mohr- Coulomb material and to contribute a strength component proportional to the fraction of the failure plane that is intact rock (Jennings, 1970). An alternative approach by Stimpson (1978) applies Lajtai's (1969) theory for shear strength of discontinuously jointed rock masses to slopes. Lajtai allows tensile failure in the intact rock of a composite surface. This theory yields lower shear strength than that of Jennings (1970) except in the presence of high normal compression, however it also fails to account for the stress concentration at the tip of a discontinuous joint. For a given slope geometry, stresses increase with slope height, but in both of these models rock mass strength is independent of size. A fracture mechanics analysis shows that particularly for small slopes, rock mass strength decreases with size. A continuous stepped failure surf ace produced by propagation of preexisting joints may develop at lower shear stress than predicted by the Jennings (1970) or Lajtai (1969) models. This fracture mechanics model applied to slopes in competent rock is more realistic in its assumed failure mechanism, and for large slopes more conservative than the Jennings (1970) or Lajtai models (1969).

Jan 1, 1984

By R. Schuhmann, J. Th. Overbeek, P. L. De Bruyn

W. E. Ewers (Commonwealth Scientific and Industrial Research organization, Melbourne, Australia)— Any attempt to elucidate further the meaning of the contact angle, particularly if it deals with the magnitudes of those mysterious quantities rsa and YRL, is certain to receive attention from those interested in the fundamentals of flotation. It is imperative, therefore, that attention should be drawn to a serious defect in the treatment by de Bruyn, Overbeek, and Schuhmann. Their Eq. 5 dy = — ld/u — Th2odiH2n states correctly the relationship between the change in surface free energy dy, the surface excesses Tx and Th2o of the components x and H2O and the changes du, and dph2o in the chemical potentials of these components. This equation applies for constant pressure and con- stant temperature and for the interface of the solid in contact with the solution of X. The relation remains valid when 1.1 is defined so that TH2O becomes zero and the equation becomes dr = — r:dur [17] From this equation de Bruyn et al. correctly concluded that increased adsorption of the collector at the liquid solid interface would reduce the interfacial energy ysl. Their second conclusion, however, that an increase in the contact angle, corresponding to a greater decrease in rsa than in rsL can be attributed to greater adsorption of X at the solid-air interface than at the solid-liquid interface is quite unjustified. The portion of the solid surface from which the collector solution has been displaced by air must be considered in terms of the equilibria between the gaseous phase and the surface. If the pressure and temperature

Jan 1, 1955

By Van Manning

IN SUBSTANCE, the international aspects of the petroleum industry, as these relate to the United States, are as follows: The domestic production is not keeping pace with the domestic demands; our best engineering talent warns us of the imminence of a decreased production by our oil wells, although more oil is needed; and the only practical source whence this increasing demand can be supplied for some time to come will be the foreign fields. Other nations have given thought to the future and, in recent years, have shown a tendency to adopt strong nationalistic policies regarding their petroleum resources, policies that hinder or prevent the exploitation of these resources by other nationals. In consequence, we find that, facing a probable shortage of the domestic supply, our nationals are excluded from foreign fields; and this in spite of the fact that foreign nationals have been permitted to enter into and exploit, our own oil resources on an equality with American citizens and without hindrance or restrictions. This country: has supplied the larger part of the petroleum consumed by the world and yet, with a failing supply imminent, it finds that those countries that have been drawing upon our resources to supply their needs are showing a tendency to exclude us from their resources. In this way we shall be transferred from a position of dominence to one of dependence; and only by sufferance of those countries that are now seeking financial or political control of petroleum supplies, shall we be able to obtain the oil we will need.

Jan 2, 1920

By W. F. Tanner

A river delivers a given load of sand, and hence heavy materials, into the sea. The load is fixed by drainage basin characteristics and processes. Wave energy available for redistributing that load is fixed in an entirely different way. An equilibrium diagram of these two parameters (load vs energy) pennits a tentative prediction of what will happen to the heavy minerals. Alluvial rivers transport a mechanical load which consists essentially of wash load (finer than about 0.05 mm in particle diam), bed load (coarser than about 0.10 mm) and the transition sizes in between. A few rivers carry no appreciable mechanical load, and are excluded from this discussion. An example of the latter is the Suwannee River of Florida, which empties across an oyster bar into the Gulf of Mexico and does not build a delta despite the absence of significant waves or currents in that part of the Gulf. An alluvial river may deliver its load into a protected sediment trap (such as an estuary, sound or lagoon), onto a low-energy coast (where it builds a delta) or onto a high-energy coast (from which spot the river load is swept away). The nature and disposition of the load depends, obviously, on three sets of factors: 1) drainage basin characteristics and processes, which determine quantity and make-up of the load; 2) coastal structure and geomorphology, which determine the kind of river-sea coupling which

Jan 1, 1962

By Willard H. Tracy

The method of seismic reflection prospecting has many times been compared to sound ranging, a process that became familiar to many during the World War. According to this very simple theory, the dynamite goes off and sends out a compression wave, which meets a reflecting horizon and returns to the surface, where it is recorded and the elapsed time of its travel in the earth accurately determined. Computations are then made on the general theory that the longer the elapsed time, the greater the depth of the reflecting bed. While this serves to give an idea of the fundamental basis of the process, it suggests a simplicity that does not exist in the life history of the various waves set up by a dynamite explosion in the earth. To begin with, a seismic wave in the earth does not obey the same simple laws of propagation that apply to a sound wave in the air. The property of strength in shear possessed by solids introduces a factor that sets such waves apart from the ordinary air waves. Also, the transmission charactcristics of the earth vary widely from place to place, and a fairly accurate knowledge of the space relationships of these variations is necessary if the final results are to be understood. Besides the waves recorded and used in the reflection computations, there are many

Jan 1, 1940

By D. Jenkins

The Franklin Laboratory was designed mainly for the analysis of the products from the two concentrating mills situated at Franklin and Sterling Hill, the most important determinations being the zinc, iron, manganese, lime, moisture, and silica contents of the ores. Within the last 4 years, however, it has been found advisable to examine most of our supplies, and therefore additional space and equipment was allotted for the examination of such substances as oils, greases, soaps, alloys, fuels, paints, explosives, and water. The building as shown in elevation (Fig. 1) and plan (Fig. 2) consists of a main or routine laboratory, an experimental laboratory, a water analysis room, and the other accessories such as stock room, library, sampling and drying rooms, and office. The main laboratory is further divided into a balance room and zinc analysis room. As the greater part of our determinations are volumetric, good light is a very important factor and with this in view the interior malls of the building were constructed of white enameled brick laid in Keene cement. These also have the additional advantage that they give a clean and attractive appearance to the room. The windows are large, being 76 by 44 in. and even on very dark days the light is good throughout the whole laboratory. Our zinc titration requires a constant light and as, on many days, especially in winter, the light is variable, we installed two Artificial

Jan 1, 1918

By R. V. Ramani, Robert Stefanko

The more stringent ventilation requirements of the 1969 Act have created a greater need for improved network analyses. More air is required at the last open crosscut (9000 cfm) and for the first time a minimum quantity is specified for the face (3000 cfm). Severe restrictions are placed on both belt and track haulage, and the intake air cannot contain more than 2 mg per cu m of respirable dust, to be reduced to 1 mg later. Larger tonnage and longer life mines are the trend today, necessitating multiple fans and shafts. Yet relatively little engineering goes into designing the mine ventilation system. In this paper a ventilation system is designed for a typical Pittsburgh block system, manual calculations are made and then checked by a computer solution. The computer is the ideal tool to try out proposed changes on paper to insure that the entire mine is properly ventilated and no costly adjustments need be made by dumping air. While it is theoretically possible to solve complex ventilation network problems by hand, it is not practical to do so because of the tremendous man-hours required and the many opportunities for errors. Thus the digital computer is indispensible to the ventilation engineer and newer improved ventilation programs are being developed to more realistically model mine ventilation networks. Suggested ventilation changes to comply with the new regulations are also critically evaluated.

Jan 1, 1973

By Yasuo Omori

Stabilized blast furnace operation at high production rates and reduced coke consumption requires control of the gaseous distribution within the furnace. This can be achieved only by an increased use of agglomerates in the furnace burden, and control of the radial distribution of agglomerates and that of coke in the blast furnace. Dissection surveys of commercial blast furnaces recently conducted by several steel plants in Japan gave much valuable knowledge on the behavior of agglomerates within the blast furnace, specifically in regard to the softening-melting zone. The authors analyzed these survey results in conjunction with laboratory studies on the behavior of agglomerates, then proposed appropriate test methods to determine high temperature behavior. A reducibility test at temperatures over 1100°C, a test for softening and melting under load up to 1400°C, and a test for melt-down characteristics were developed to evaluate behavior of agglomerates in the softening-melting zone of the blast furnace. The high quality of self-fluxing sinter, as compared with pellets, was verified by means of these test methods. The test conditions of the respective test methods were examined in detail.

Jan 1, 1977

By R. Neilson Clark

THE discovery of a thin pay streak, yielding carbonates of copper, native silver, and perhaps chloride of silver, was made on the 9th of April, 1874, within the trachytic belt which forms part of the Sierra Mojada. The discoverer named it the Humboldt Mine. On the 2d of May, 1874, another discovery was made, in a northwest direction from the Humboldt, at about five hundred feet distant, this was named the Pocahontas Mine. After some exploration these two discoveries were proven to be on the same vein. To the southeast of the Humboldt a claim had already been taken up, called the Virginia; and to the northwest of the Pocahontas, one called the Southeast Leviathan. On these last two this same vein has been found and worked. This paper will therefore treat of the Humboldt-Pocahontas vein, as worked on these four claims, to wit: beginning at the northwest, the Southeast Leviathan, the Pocahontas, the Humboldt, and the Virginia claims. Since the spring of 1874, there has been sunk on this vein a total of twenty-seven hundred and fourteen feet of

Jan 1, 1879

By A. Donald Kelmers, Forest G. Seeley, B. Zane Egan

INTRODUCTION Coal ash, presently the fifth most abundant of the solid minerals produced in the United States, is expected to become the fourth most abundant by the end of this decade (1). The production of fly ash from the combustion of pulverized coal amounted to a total of 44 million metric tons (Mt) in 1977 and is expected to Increase to 91 Mt by 1985. Coal ash, which results from the Inorganic clay and mineral content of the coal, contains several elements and thus can be considered as a mined and crushed mineral resource rather than a waste material Furthermore, potential problems associated with fly-ash disposal ponds and the leaching of potentially hazardous elements through groundwater infiltration and/or rainfall provide additional incentive for processing fly ash for environ- mental control as well as for the recovery of certain metal values. Fly ash could provide an abundant domestic source of aluminum and several other metals Aluminum is now recovered from bauxite, and over 90% of this ore is imported since domestic sources are limited and cannot meet the U.S. demand There is a close relationship between the aluminum content of fly ash and the domestic consumption of this metal (Table 1).

Jan 1, 1981

By Franklin Bache

It is appropriate to the place of meeting, and of interest to those members of the Institute whose attention has been more or less directed to Virginia during the past eleven years, to know the result of recent developments of the Virginia coal-field. While, during the late " boom," the attention of the industrial pioneers of Virginia was mainly directed to iron-ore deposits and manufacture, it is safe to say that the coal to which, at that time, comparatively little attention was turned, and which did not directly foster a growth of " boom " towns, will prove the most reliable source of mineral wealth in the State. At the time of the last Virginia meeting of the Institute, held at Roanoke, in 1883, the Wise county coal-field was untouched by a railroad, and its economic existence was scarcely considered. Although, in the meantime, a number of reconnaissances had been made, and a fair estimate of the value of the field formed, it was not until 1891, when the Norfolk and Western and the Louisville and Nashville railroads, respectively, completed their Clinch Valley and Norton extensions to a junction at Norton, Wise county, that any development took place, and not until 1892 were shipments of any importance made. The coal-measures of Virginia are confined to the seven counties of Buchanan, Tazewell, Dickenson, Russell, Scott, Wise, and Lee,

Jan 1, 1895

By C. H. Jr. Herty

FEW subjects have attracted the attention of metallurgists more than ,oxygen in steel. From the days of Mushet and Ledebur interest in this subject has been increasing, and as additional knowledge has become available, the problem has naturally grown more complex. Instead of using the simple term "oxygen" we now distinguish between iron oxide, silicates of various kinds, oxysulfides, oxygen as gas and oxygen in solid solution in steel. There are five general methods for determining oxides in steel: hydrogen reduction;, vacuum fusion; various wet-extraction methods, including electrolytic methods; methods depending on volatilization of the iron away from the oxides; and metallographic methods. For oxygen in solid steel each of these methods has both advantages and disadvantages. The hydrogen-reduction method is of no use on steels above about 0.20 per cent. carbon;1 furthermore, it gives only FeO and possibly some MnO. The vacuum-fusion method2 is expensive and gives total oxygen, with the exception of some A1203, and does not differentiate between the various oxides in which the oxygen exists. Most of the wet-extraction methods' give only the more insoluble oxides Si02 and A1203, though the iodine method gives MnO to an uncertain degree (information that may be more misleading then no information

Jan 1, 1930

By Ajoy K. Ghose

INTRODUCTION Longwall mining made its debut in Indian coal mining scene around 1900. Despite this headstart, the application of the method has been slow and halting. Currently, there are some 16 operating longwall faces only in different Indian coalfields contributing to perhaps less than 3 percent of the total underground coal production. Ambitious plans for expansion of longwall mining notwithstanding, apprehensions on the cavability of Indian coalmeasure roof rocks and some unsavoury experiences with face collapses in caved longwalla have impeded wider adoption of the technique. Between 1960 and 1983, some 41 caved longwall faces were worked in Jharia, Raniganj, Karanpura and Korba Coalfields in India, of which 6 faces reportedly had collapsed(1). The first powered support longwall face was started in August 1978 at Monidih colliery which marked a major step forward in the introduction of advanced technological system in Indian coal industry. This paper attempts to analyse critically the experiences with longwall ground control in caved longwall faces in India. Experiences from powered support faces at Monidih, Dhemomain and Pathakhera are synthesized to provide an appraisal of the present status of caved longwall faces under the Indian coalmeasure roofs, which thus far have been characterised as “massive”. The geotechnical site factors at the powered support faces are evaluated and conclusions drawn on the pre-assessment of caving characteristics and support resistance required at the faces.

Jan 1, 1984

By D. Harrington

TheRe has been, during the past year, a wealth of report data and discussion relating directly or indirectly to various phases of ventilation of metal mines, and many of the data are from foreign sources. The phase of the subject most generously accorded the attention of the technical press is that of cooling mine air, with much less attention to other fairly intimately associated features such as fan performance, friction factors, fires, mine gases, mine lighting, health of miners, and ventilation standards. Cooling Mine Air South Africa, with its very deep mining on the Rand and with fairly high working temperatures, 'contributes the most definite data on the subject of cooling mine air, and undoubtedly the most interesting issued are those from a paper by J. H. Dobson,' in which he gives a comprehensive review of the subject as gleaned largely by analyzing the data in three papers.2 Dr. Dobson's summation is decidedly interesting. In general it is recognized that the introducing into the mine and circulating to the working places of large volumes of pure air is the most effective method of giving deep, hot metal-mine workings reasonably efficient working conditions. A tabulation as to the cost of securing various amounts of cooling by circulating various volumes, from 230,000 to 760,000 cu. ft. per min., indicates that there are cost limits beyond which increase of quantity of air in circulation is impracticable, as the annual cost of circulating 230,000 cu. ft. of air per min. in a certain mine at a depth of

Jan 1, 1928

John Eliot Allen has been made acting head, dept. of geology, New Mexico Institute of Mining and Technology, Socorro, N. Mex. He had been associate professor of geology. Robert B. Anderson has accepted a position with the U. S. Steel Co., Gary, W. Va., as assistant to the superintendent, No. 2 mine. [ ] Donald L. Archibald has joined the sales dept. of the Ellicott Machine Corp., Baltimore. He formerly had been associated with the Joy Mfg. Co., St. Louis. J. C. Boswell has been appointed manager of the Fairbanks dept., United Smelting Refining & Mining Co. J. B. Metcalfe has been appointed assistant to the president. G. Howard LeFevre was elected vice-president and general manager of metal sales and R. N. Hunt, vice-president and chief geologist was elected a director. R. B. Earling, vice-president and general manager of Alaskan operations, has retired but. will con¬tinue to serve on the board of directors. J. D. Crawford has been appointed general manager of Alaskan operations.

Jan 1, 1952

By Reginald S. Dean

THE commercial availability of electrolytic manganese has greatly changed the position of manganese as a nonferrous alloying metal. Manganese metal commercially available up to about ten years ago was reduced with either silicon or aluminum and contained substantial amounts of the oxides of these metals and other impurities. Manganese was accordingly not available as an alloy base and its addition to copper-base and nickel-base alloys was generally limited to a manganese content of a few per cent. Several special alloys like manganin contained up to 12 pct of manganese. A method for the production of electrolytic manganese was developed by the Bureau of Mines in 1936 and commercial production was begun in 1938. At the present time (June 1951), production is about 12 tons per day but appears likely to be substantially increased. Electrolytic manganese is deposited from an aqueous electrolyte containing manganese and ammonium sulphates and is marketed as cathode fragments about 1/8 in. thick. The impurities in its composition are as follows: iron, 0.0015 pct; copper, 0.001; arsenic, 0.0005; cobalt, 0.0025; lead, 0.0025; molybdenum, 0.001; sulfide sulfur, 0.017; sulfate sulfur, 0.014; insoluble, 0.002; carbon, 0.002; hydrogen, 0.015. These figures are from Bulletin 463, U. S. Bureau of Mines. From an alloying standpoint, the most important impurity is hydrogen. This can be removed by heating; 95 pct of the hydrogen can be removed in this way without introducing significant amounts of oxygen or nitrogen. Much of the commercial electrolytic manganese used in alloys is dehydrogenited by the producer, since the amount

Jan 1, 1953