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POLITICAL developments, the impact of Korean warfare necessitating immediate rearmament plans, and recent developments in mining taconites have focused attention on their immediate exploitation to fill the gap created by diminishing reserves. The question of rich foreign ores versus low grade development is past-we need both sources with emphasis on the immediate large scale mining of taconites. In the past three months several things have occurred which add to the taconite picture: (1) Pellets have been used successfully in the blast furnace by Armco. (2) In Congress HR 8512 was introduced by Congressman Blatnik of Minnesota to amend the lending powers of RFC to permit long term loans on basic mining developments, particularly the taconites, which may be needed for the strengthening of the national economy. (3) Walter S. Tower, president of the American Iron & Steel Institute, announced that American steel companies are planning expansion of 6,000,000 tons of steelmaking capacities in the next few years. (4) The outbreak of war in Korea has obliged the United States to rearm and make plans for a semipermanent defense establishment to which 10 to 12 pct of the national income will be budgeted. (5) Startling new advances have been made in the Linde Air Products Co.'s jet-piercing drilling. The United States is now confronted with the problem of increasing its steel capacity and at the same time of securing enough iron ore to supply this increase as well as make provision for the rapidly decreasing supply of rich iron ore on the Mesabi range. Taconites, the low grade iron ore at the east end of the Mesabi, of which there are literally billions and billions of tons of easily concentratable magnetic ore, are the immediate answer. According to the Wall Street Journal on July 24: "Reserve Mining Co., backed by such steelmakers as the Armco Steel Corp., Wheeling Steel Co., Republic Steel Corp., is reported ready-as soon as the pending bill clears (HR 8512)-to seek a $100 million federal loan to build a taconite processing plant at Beaver Bay, Minn., to produce about five million tons (of pellets) annually of 60 pct to 65 pct in iron ore . . ." Experimental work indicates that pellets may be the final form, rather than nodules, agglomerates, or sinter. At Ashland, Ky., the Reserve Mining Co., which has obtained a

Jan 9, 1950

In accordance with the usual custom, manuscripts to be presented at the next meeting of the Institute must be in the hands of the, Secretary before July 1, 1917. Manuscripts to be properly distributed in advance of the meeting must be in the hands of the Secretary before June 1, 1917. At the last meeting of the Institute 45 papers were presented, and 42 of them were actively discussed. This experience makes us believe that advance distribution is the best possible means of getting a good discussion of papers and of securing for them the interest of the members of the profession. It will be impossible, however, to give the papers proper distribution if they bare not received before June 1, 1917.

Jan 4, 1917

By D. S. Jacobus

It is proposed to give in this paper an estimate of the cost at which carburetted and uncarburetted water-gas will have to he sold, in order to compete successfully for steam-boiler use with anthracite coal. The following are analyses of the gas direct from the generator, and of the same after it has been carburetted for illuminating pnrposes. Per cent. by Volumes. I. 11. Uncarburetted. Carburetted. Nitrogen,.4.69 2.5 Carbonic acid,.3.47 .3 Ethylene,....... 0 12.5 Oxygen,....... 0 .2 Benzole vapor,...... 0 1.5 Carbonic oxide,.36.80 29.0 Marsh-gas,.2.16 24.0 Hydrogen,.52.88 30.0 100.00 100.0

Jan 1, 1889

By Burt C. Mariacher

Extraction of uranium from ores is being accomplished by processes which, for the most part, subject the entire ore to acid or carbonate leaching. Ore deposits with a U3O8 content below 0.10 pct U3O8 are seldom considered suitable for treatment by leaching. A preliminary concentration that would enrich the uranium content of an ore by a simple, low cost process based on physical properties of the ore might result in some low grade deposits becoming commercial ores. In addition, the process might be employed in existing operations to reduce transportation and leaching costs and to increase capacity of existing leaching plants.

Oct 1, 1956

By C. E. Birchenall, H. M. Schadel, G. Derge

EXISTING distribution data' for silicon between liquid iron and silver at steelmaking temperatures, 1500" to 1600°C, has made activity relationships in liquid silver-silicon alloys desirable as a method of determining the silicon activity in molten iron. To this end, through the use of radioactive Ag110 and the molecular beam technique described in a previous paper,' the vapor pressure of silver as a function of temperature has been measured over three silver-silicon alloys containing 3.9, 9.3, and 15.4 atomic pct (eutectic composition) silicon. The technique was that described for pure silver with the exception that a porcelain liner was used inside

Jan 1, 1951

By N. E. Bonn

IT is well known that most of the materials entering into the manufacture of thermocouples are subject to variations in their thermoelectric characteristics, the chief causes of which are: differences in chemical composition; the previous .history, which includes mechanical working, ageing, oxidation, and contamination; and mode of use, such as depth of immersion, etc. In the case of a very extensively use thermoelement, the iron-constantan couple, neither iron nor constantan are absolutely uniform, and a number of checks are made during the process of manufacture. As both are subject to diversion from a standard value, neither, can be used for checking the other. It is, therefore, necessary to find a third metal against, which iron and constantan maybe checked. It was to find such a metal; that the present investigation was undertaken. To be a reliable, checking standard, the metal must possess a fairly high melting point? it must be obtainable in sufficient purity, and it must be uniform and constant with respect to its thermoelectric qualities. The choice is, as a result, limited to a few metals, such as copper, gold, and silver. Copper has the advantage of low cost, which makes it possible to use each wire only once and thus avoid any variations due to continued use, although previous investigators have found1 that continued use does not affect the calibration of a copper-constantan thermocouple. Copper also has the advantage of a large thermal electromotive force against constantan and would be desirable as a checking standard if it could be shown that it possessed the proper thermoelectric characteristics. The investigation, accordingly, resolved itself into three phases: the uniformity of commercial electrolytic copper, the effect of aging and method of annealing, and the calibration of the copper-constantan thermocouple.

Jan 9, 1919

By M. J. Hordon, M. A. Wright

The well-defined increase in fatigue life observed o many metals cyclicly strained at vacuum levels below 10-1 to 10-3 torr has been attributed to the critical retardation of oxygen or water vapor chemisorption at the crack tip during crack propagation.1-3 In the absence of strongly adsorbed surface films, crack re-welding during cyclic compression or dislocation escape from the plastic zone around the crack tip has been proposed to account for the observed decrease in the rate of crack growth. The increase in the critical pressure required for the transition in crack growth rate with temperature experimentally determined for aluminum was found to be generally in accord with the adsorption rate model.4 However, although the adsorption mechanism would also predict an increase in transition pressure and fatigue life with increase in cyclic loading rate, and such effects were noted by Snowden5 for lead and Hordon3 for aluminum, the opposite results were reported by Kramer et al.B in studies on aluminum. The present note describes some recent measurements of the fatigue properties of 1100-H14 aluminum at low pressures to determine the specific effect of cyclic strain frequency in the transition pressure range. Flat cantilever-type specimens of 1100-H14 aluminum shaped to produce a uniform strain gradient along the gage length were tested in reverse plane bending at constant deflection amplitudes in two independent multi-specimen vacuum fatigue systems. One series of tests using 2-in. gage length specimens was conducted in an ion pumped apparatus with 107 torr and 50 cps capacity, denoted as Unit I, utilizing fixed mechanical cams to impose the strain amplitude. An independent test series using shorter 1-in. gage length specimens was conducted in a cryopumped apparatus designed for extremely low pressures below 10-10 torr, denoted as Unit II, using an electromechanical vibrator at non-resonant frequencies up to 150 cps to provide the deflection. Both vacuum fatigue units and associated test procedures have been described previously.3'7

Jan 1, 1969

By Joseph R. Stephens

Deformation substructures of' polycrystalline tungsten, W-2, 9, and 24 pct Re, and W-3 pct Ta were studied by tra?zsrnission electron microscopy. The stress-strain curve for unalloyed tungsten showed gradual yielding followed by work-hardening. Electron nzicrographs indicated a gradual increase in dislocation density with increase in strain up to 5.0 pct. Dislocations, although frequently jogged, were straight over moderate distances and were in a randorn array. Stress-strain curves for alloy specimens of W-2 and 9 pct Re and W-3 pct Ta exhibited a drop in stress at yielding followed by only slight work-hardening. Electron micrographs of these specimens after strains of 0.05, 0.1, and 0.5 pct revealed no change in dislocation substructure from the unstrained specimens. After 2.0 pct strain, the three alloys exhibited dense networks. W-3 pct Ta was characterized by straight, frequently jogged dislocations comparable with the dislocation structure in unalloyed tungsten after a similar amount of strain. In contrast, W-2 pct Re exhibited dislocations that contained widely spaced jogs, while W-9 pct Re had developed a cell structure after the relatively srnall strain of 2.0 pct. The W-24 pct Re alloy contained a few dislocations after 0.1 pct strain, while after 0.5 pct strain twins were evident. Dislocation slip bands apparently preceded the twins. The stress-strain curve for the alloy indicated that twinning commenced after approximately 0.25 pet strain. These results indicate that the primary effect of low rhenium concentrations (2 and 9 pct) in tungsten is to increase dislocation multiplication after macroyielding by reducing the Peierls-Nabarro force (lattice resistance to dislocation motion). The dislocation bands that precede twins in W-24 pct Re may be caused by localized internal stresses resulting fro a metastable structure, for example, clustering of rhenium atoms. The effect of high rhenium additions (22 a 65 pet* Rproperties of tungsten. Klopp, Witzke, and Raffo5 reported bend transition temperatures as low as -100°F (200°K) for dilute electron-beam-melted W-Re alloys tested in the worked condition. Recrystalliza-tion increased the bend transition temperature, but alloys with 2 to 4 pct Re were still markedly superior to unalloyed tungsten. Fractographic examinations of tungsten and W- 3 pct Re and W- 5 pct Re alloys by Gilbert 6 revealed that these low rhenium alloys showed a greater tendency toward cleavage failure than did tungsten. Garfinkle 7 showed that rhenium additions, up to 9 pct, to (100) oriented tungsten single crystals increased the proportional limit stress and decreased the flow stress and the rate of work-hardening. In addition, while deformation in unalloyed (100) oriented crystals apparently involved both (110)100) and (112) slip, crystals with rhenium contents of 5 andpct or more deformed primarily by (112) slip. The mechanism by which high and low rhenium additions affect the mechanical properties of tungsten is still not well-established. The present investigation was undertaken to determine by transmission electron microscopy the effects of low rhenium additions, 2 and 9 pct, and a high rhenium addition, 24 pct, on dislocation substructure in the early stages of deformation of polycrystalline electron-beam-melted tungsten. Unalloyed tungsten and a W- 3 pct Ta alloy were included for comparison. EXPERIMENTAL PROCEDURES Materials. Triple electron-beam-melted tungsten, W-2, 9, and 24 pct Re, and W- pet Ta were used for this investigation. Chemical analyses of the cast ingots are given in Table I. A description of the starting metal powders and melting and fabrication pro-cedures for unalloyed tungsten and the W-Re alloys is reported.5 The W-3 pet Ta alloy was processed in a similar manner. Compression specimens measuring 0.300 in. (7.6 mm) in length by 0.130 in. (3.3 mm) in diam were machined from swaged rods. All alloy specimens were annealed in a vacuum of 8 x 10- 6 Torr (10'2iVper sq m) for 1 hr at 3600°F (2255°K). The recrystallized grain size ranged from 0.06 to 0.08 mm diam for the alloy specimens. Unalloyed tungsten was annealed at 2400° F (1589°K) for 1 hr to produce a recrystallized grain diameter of approximately 0.12 mm. Specimens were electropolished in a 2 pet NaOH solution to a diameter of 0.125 in. (3.18 mm) to remove surface notches resulting from grinding and to improve reproducibility of t data. The ends o the compression specimens were ground flat, parallel to each other, and perpendicular to the longitudinal axes with 4/0 emery paper. Compression Tests. The compressive stress-strain apparatus used for compression tests is described in detail by Stearns and Gotsky.9 Room-temperature compression tests were conducted at a crosshead speed of 0.01 in. per min (0.25 mm per min).

Jan 1, 1969

By Thomas N. Walthier

ROSPECTING for uranium in the East is hampered by the lack of bedrock exposure due to extensive overburden and residual soil. But, despite the problems of this physiographic province, it has not been ignored in the search for radioactive materials. Since 1951 both the U.S. Geological Survey and the Atomic Energy Commission have had field parties in the eastern U.S. Tempo of private prospecting is increasing, and many discoveries have resulted. AEC work so far has been concentrated in the areas of most numerous discoveries-Pennsylvania, New Jersey, and New York. Accounts of uranium mineralization in the eastern U.S. are found in the old literature and one site in the Mauch Chunk area of Pennsylvania has been known since 1874. In 1949 McKeown examined the original occurrence there and found another southeast of the town. The deposit appeared to have commercial possibilities and a short period of production began in July 1954

Jun 1, 1955

By Joseph A. Holmes

Iv all new movements unavoidable misapprehensions arise, which should be cleared away, lest they retard the progress of the movement itself. An impression has gone abroad that the movement for conservation of resources is a new movement. No one knows better than the engineer that this is not the case. Men like Douglas and Raymond and John Fritz and Edison and McDonald, and hosts of others, have preached and practiced conservation as applied to mineral resources throughout a long and useful life-time; and, in general, the work of the engineer and the chemist, both in this and in other countries, has been along the line of continually greater efficiency in the use of all available materials. And the results already accomplished through the efforts of these experts are now saving annually many millions of dollars to the people of the United States in materials and labor. It is true, however, that the need for conservation, that is, for a wiser and more efficient use of the natural resources, has taken on a new life, and is being brought home to the people of the United States in a manner which is awakening public interest and even the public conscience. It is, therefore, both appropriate and fortunate that the engineers, the chemists, and the thinking men of all classes are availing themselves of the present impetus to the movement to emphasize anew the lessons which heretofore they have found it more difficult to impress upon the American public or even upon the captains of industry. Still another of these misapprehensions is to the effect that many of the leaders in the present movement hope to bring about conservation of resources through legislation or execu-

May 1, 1909

By S. R. Smith, W. M. Voorhis, J. D. Young

The Tennessee Valley Authority (TVA) has conducted investigations to identify the major causes of coal pile inventory adjustments. This paper describes past and current attempts to improve inventory survey accuracy and reduce costly inventory adjustments. The unique interaction between accountants and engineers is also reviewed. Data and results of a recent field test wing downward-looking radar developed by Ohio State University are presented. These show great promise in determining coal pile depth and density, thus improving inventory accuracy. This electromagnetic remote sensing technique, if successful, would provide an optimum technical and economic method of surveying all 12 TVA stockpiles without costly borehole drilling or disrupting stockout and reclaim activity. The effect of changing coal quality to meet environmental standards has made accurate coal pile density measurement more important than ever in reducing the costs of electric power generation from coal.

Jan 1, 1984

By Richmond Bennett

Airborne geochemistry became a reality with the advent of a high-sensitivity air¬borne gamma ray spectrometer with large volume NAI(Tl) crystal detectors. The high-sensitivity spectrometer measures small variations in the concentration of potassium (as Ks°), thorium (as Tl308) and uranium (as Bi.214) along the flight lines in the area surveyed. Hydrothermal dispersion patterns are indicated by anomalous measured values of the concentrations of potassium, thorium, uranium, or their ratios. In two recent Australian survey areas, copper mineralization was located along favorable structures within hydrothermal dispersion patterns delineated by airborne geochemical surveys. In metamorphic terrane where there had been po¬tassium metasomatism, the hydrothermal dispersion patterns were indicated by high potassium/uranium ratios (K40/Bi). In a sedimentary environment that had been intruded by a stock, the path of hydrothermal fluids was indicated by uranium (Bi214), thorium (TV'), and uranium/ thorium (Bi214/Tl208) ratios.

Jan 1, 1972

Jan 1, 1932

By H. Rush Spedden

When Robert H. Richards wrote Ore Dressing, the famous four-volume work published in the first decade of this century, the ore dresser was still largely concerned, with the mechanical treatment of ores. Since then, however, economics have transformed him into a mineral processing engineer who must increasingly deal with closely integrated facilities designed to produce a commodity for manufacturing. Moreover, this change will grow marked as the complex low- grade ores of the future make it ever more necessary for him not only to use the best combination of pyrometallurgical, hydrometallurgical and physical separation processes, but also to integrate these processes at the mine site. Nor are economic pressures the only ones propelling the processing engineer into a new era. The ecology drive has thrown him into a new situation in which his economic base is radically altered, and it could well precipitate as drastic a revolution in his technology as that which took place when flotation was developed.

Jan 1, 1971

By I. R. M. Chatson

Radial layout's guiding principle is the grouping under one roof of the operating processes which require continuous supervision. Separate treatment sections are isolated by outside stockpiles fed with radiating conveyors. Hence the name "radial" layout. Many plants are designed with "linear" layout where successive operating stages are dotted like beads along a string of conveyors.

Jan 11, 1978

By James W. Lower

IN developing the orebody on lower levels of the Star mine at Burke, Idaho, Hecla Mining Co. is faced with a serious problem in driving raises. Levels are at 200-ft intervals. As a raise is being driven between levels, at points about 70 and 130 ft from the sill, heavy pressure arches develop and the raise becomes extremely hazardous. Eventually, following a blast, caving occurs, making it impossible to recover the raise. In February 1957 it was decided to attempt sinking a small winze on the vein from the 5500 to the 5700 level. This shaft (winze-raise No. 2) was to be used as a raise prior to stoping. It was assumed, and correctly, that the heavy ground pressure could be controlled by timbering close to the bottom after each advance.

Jan 7, 1958

By R. B. Tippin, J. S. Browning

Inasmuch as the higher grade potash deposits are rapidly being depleted, it is important that economic beneficiation techniques be developed for recovering potassium compounds from lower grade sylvite ores and deposits containing clay materials. The Federal Bureau of Mines has conducted research to develop processes for heavy liquid concentration of potash ores, This method of concentration is discussed, and results of tests made on potash ores from New Mexico are presented. The tests demonstrated the technical feasibility of producing near commercial-grade potash concentrates, with a high recovery of the contained sylvite. The concentration of minerals based on their differences in specific gravity dates back to the very beginning of mineral dressing, and the use of heavy liquids in the laboratory to achieve optimum mineral separations has been utilized for many years. With the advent of froth flotation and its success, the incentive to develop new processes has remained relatively dormant. However, flotation refinements in the nonmetallic ores have not progressed as rapidly as in metallic (sulfide) ores because of the complexity of the deposits and the chemical similarities of the minerals.

Jan 1, 1967

By S. Nenno, T. Saburi, Y. Mizutani, M. Yomarnoto, K. Komatsu

In the equilibrium phase diagram of the Ni-Mo sys-tem1,2 available at present, intermetallic compounds (or ordered phases)ß(Ni4Mo) and ?(Ni3Mo) are known to exist to the nickel rich side. In our recent investigations on Ni-Mo alloys, however, it has been found that the quenched alloys from the high temperature region containing more molybdenum than the Ni4Mo do not decompose directly into 0 and when annealed isothermally below the peritectoid temperature, i.e., 865°C. This note is to report the existence of Pt2Mo type superlattice (possibly ordered Ni2Mo) as a metastable phase in the early stage of decomposition. Alloys containing 20.1, 22.7, and 24.4 at. pct Mo were prepared by vacuum-melting electrolytic nickel of 99.9 pct purity and molybdenum powder of 99.9 pct purity in an alumina crucible. From the resulting ingots, sheets 0.3 mm thick were obtained by forging, hot-, and cold-rolling. The sheet specimens were water-quenched from ! region and subsequently annealed for various periods of time at temperatures below the peritectoid temperature. On these specimens were made optical-microscopic and transmis-sion-electron-microscopic observations. Fig. 1- Optical micrograph of the 22.7 at. pct Mo specimen annealed for 100 hr at 700°C after quenching. (ß + ?) region, B, nucleated along a grain boundaries are invading the preexisting (ß + Ni2Mo) region, A. Details of A are observable only by electron microscopy. Etchant: 60 pct HNO3-40 pct CH3COOH.

Jan 1, 1970

A special war committee of the Engineering Council has been appointed to assist other committees of the United Engineering Societies having to do with the development of the arts and sciences related to warfare. One of the principal functions of this additional committee is to pass upon the probable value of new inventions. The new committee has established headquarters' in the rooms of the Naval Consulting Board in New York City, and has received the franking privilege of the Post Office Department.

Jan 1, 1918

Jan 1, 1940