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By Donald H. McLaughlin

THE primary function of the mining engineer is to find mineral deposits and fuels in the accessible rocks of the earth and to recover them for the vast needs of our complicated civilization. On him has been placed the responsibility for the exploitation of the nation's and world's mineral resources. The degree to which the minerals of the earth have been utilized serves to an extent as a measure of man's material advancement, as well as an index of the relative strength of nations. The natural endowment of lands, varies greatly, but the intellectual energy of a people is revealed by the way in which they take advantage of their heritage of minerals or reach out to less developed regions by exporting their engineering skill as well as capital to secure the raw materials they need.

Jan 2, 1953

By J. H. Keeler

AN alloy of zirconium containing 18 atomic pct Cb was found to be body-centered-cubic and readily deformable at room temperature. The behavior of this alloy provided an opportunity to determine if

Jan 1, 1957

By J. W. Downey, A. E. Dwight, R. A. Conner

In a previous paper' we have reported the existence of a number of AB2 Laves phases in which A is a member of the scandium group (including the 1an-

Jan 1, 1967

Jan 1, 1940

Jan 1, 1940

Jan 1, 1881

By E. J. Roberts, E. B. Fitch

Most classifiers in use today are, in function, settling pools. A fluid suspension of particles is passed through a pool at such a rate that only a fraction of the particles-the coarser fraction-has time to settle out of suspension. The rest are carried on out of the pool as overflow. The most fundamental way in which such classifiers differ is in the mechanism used to remove the settled particles from the pool. The particles may gravitate from the pool, as in the various sand cones, or they may be conveyed mechanically from the pool by drags, spirals, or reciprocating rakes. The mechanism of settling pool classification and its limitations are discussed. A method for calculating countercurrent classifications is presented. The practical validity of the calculation method has been confirmed through 20 years of use within The Dorr Co. During this time it has been used on diverse feeds and has been checked against many types of settling pool classifiers, with close agreement in nearly every case. Excellent elimination of third critical mesh particles and finer ones may be obtained in a countercurrent classifications series where all stages separate at the same mesh, but elimination of first and second criticals is inherently limited. Spectacular elimination of all criticals may be obtained by arranging successive stages to classify at successively coarser mesh. Improvement in elimination is obtained at the cost of an increased internal recirculation, but this may be tolerable in many cases.

Nov 1, 1956

By Sir Lowthian Bell

WITH the exception of air and water, it is open to question whether there is any form of matter which the human race could less easily spare than iron. Short of going the length of asserting that, without this metal for an anchor or steel for the compass, the adventurous navigator could never have crossed the wide Atlantic, we may credit the locomotive' and the steamer, and hence iron, for that sequence of events which has peopled North America with the

Jan 1, 1891

By Sherwin F. Kelly

Drilling in the Oligocene potash basin of Alsace prior to 1927 had shown important differences of level in the salt beds thus encountered. TO explain this a somewhat unsatisfactory hypothesis of faulting had been advanced. During the latter part of 1926 and the beginning of 1927 our firm was engaged by two organizations1 for the purpose of trying to supplement, by an electrical survey, the geological data this far collected. As a result of this exploration it was possible to affirm that salt dome structures were present in the Oligocene basin of the Upper Rhine, something heretofore absolutely unknown in that region. Two salt domes were actually outlined: one, near Meyenheim, was made the subject of a communication to the Academy of Sciences, by G. Friedel;2 the other, near Hetten-schlag, was briefly discussed by C. and M. Schlumberger3 before the same academy. The purpose of this paper is to indicate the stratigraphic and structural conditions of the area where these salt domes were found; to discuss the results of the electrical survey which led to the location of the domes; and to indicate the new geological outlookwhich such a discovery suggests. Stratigraphy In the southern part of the Rhine graben the Oligocene rests almost directly on the Middle Jurassic and consists, in ascending order, of: 1. Green marls, not salt-bearing, composed of fresh and brackish water deposits. 2. Middle stage, salt-bearing, consisting of lower-schistose marls and upper, variegated marls. 3. Blue marls, not salt-bearing, but including gypsum deposits; hence sediments laid down in a bay more or less connected with the sea.

Jan 1, 1929

Jan 6, 1950

Dr. Rausch, from your vantage point as educator, engineer, and corporate executive, what would you say is the most fundamental need that must be satisfied for the continuing welfare of our society, our industry and our profession?

Jan 3, 1977

By S. Yamaguchi

IN this study of thorium and uranium minerals an x-ray shadow microscope of the Cosslett type1 was used. A flux of electrons driven with a voltage

Jan 1, 1959

By R. W. Raymond

I desire to call the attention of members of the Institute to a new method of plotting and determining faults in mineral deposits, suggested by Prof. Hanns Hoefer, lately of the Mining School of Przi-

Jan 1, 1882

By Mark W. Springett

The sampling of precious metal deposits entails inherent problems due to the low mineral abundances, high mineral specific gravities, skewed grade distributions and wide ranges of mineral particle sizes. Sampling practices and precautions are discussed with particular attention to each of the tripartite stages of sampling - sample acquisition, sample preparation and sample assaying. Practical examples of approaches to the sampling problem are given and some examples of significant sources of error are provided from gold and silver deposits in North America.

Jan 1, 1984

By Elliott J. Roberts

The theory is developed that the tons ground through a given mesh per day in a wet ball mill is proportional to the percent plus that mesh in contact with the balls and the net power applied to the balls at this point. A grindability test is described.

Jan 12, 1950

By J. Weertman

High-temperature creep experiments were carried out on indium, lead, and on binary substitutional alloys of In-Pb, In-Sn, In-TI, In-Cd, In-Hg, Pb-Bi, Pb-Sn, Pb-In, and Pb-Cd. The stress at which the power law creep equution breaks down was found to be much smaller for indium and lead than for metals with larger elastic moduli. The exponent over the stress in the power law creep equation was found to decrease upon alloying from values close to 4.5 to values near 3. THIS paper describes a set of high-temperature creep experiments made on high-purity lead and indium and on lead-rich and indium-rich single-phase binary alloys of various metals. These ex- periments were carried out to check two predictions of some creep equations derived by us"2 from a dislocation creep model due essentially to Mott. This model is shown in Fig. 1. Here dislocation loops are emitted from sources, not shown, situated on different slip planes. As the loops expand they come into each others' stress fields and are stopped. However, at high temperatures, as Mott has pointed out.

Jan 1, 1961

By J. I. Paige, T. T. Campbell, A. W. Henderson, H. M. Harris

The chlorination of ilmenite concentrates and slags to produce Tic14 suitable for pigment or metal production was investigated by the Bureau of Mines along with the dechlorination of byproduct iron chloride to produce chlorine for recycle and iron oxide., Ilmenite concentrates or slag powders were fed into the bottom of a fluidized coke bed at 1,050º C using chlorine flow rates up to 20 l/min in a 10.2-cm-dim reactor. Tests showed that >95 percent of the various ilmenite concentrates reacted at optimum conditions, and recovery of TiC14 ranged from 95 to 100 percent of stoichiometric. Impurity dusts were removed from the vapors by cyclones and a fiberglass cloth filter. Iron chloride was condensed as a powder with less than 0.4 percent insoluble material. The TiC14 was collected in refrigerated condensers. Iron chloride was dechlorinated at 500º to 550º C by reaction with oxygen in a 16.5-cm-dim reactor using a fluidized bed of Fe2O3. Optimum processing was attained with a FeC13 feed containing 25 wt-pct Fe203 granules treated with 2 wt-pct NaCl catalyst; Under the above conditions, off gas chlorine concentrations of 62 to 90 wt-pct were obtained. During 2- and 3-day tests with technical-grade FeC13, conversion of FeC13 was 94 to 97 percent, chlorine concentrations were 76 to 90 wt-pct, and up to 92 pct of the stoichio- metric Fe203 was removed in the primary reactor discharge. Chlorine

Jan 1, 1976

E. T. Turkdogan (British Iron & Steel Research Assoc., London, England)—I would like to suggest a different method for the treatment of the authors' data on the Si-0 equilibrium in liquid iron. Because the activity coefficient of silicon dissolved in iron is influenced by the concentration of silicon as well as that of oxygen, the equilibrium constant K2 of reaction 2 becomes a function of metal composition, and, as shown in Fig. 1, a plot of log KP1 at 1600°C against the weight percent of silicon gives a smooth curve. A similar curve is obtained when log Kzl is plotted against the oxygen content of iron. Before

Jan 1, 1955

By J. E. Strongman

This paper describes a system dynamics model of the international copper system. The development of the model is described regarding the questions it was designed to address, model boundary, major sectors and actors, the availability of data, the copper life cycle, and major supply and demand dynamics. A base forecast is presented describing future supply, demand, capacity, prices, trade flows, scrap flows and capital expenditures from 1976-1990 for the major producing and consuming market economy blocs.

Jan 1, 1977

By James K. Grunig

As the real price of uranium increases, deposits of lower and lower grade will be treated. The various occurrences of uranium ore are described and the chemical aspects of extraction are detailed.

Jan 1, 1981