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By J. E. Spurr

CONTENTS. [ ] I. INTRODUCTION. The region here discussed is that part of western Nevada in which, during the last few years, discoveries of rich gold- and

Jan 1, 1913

By C. A. Edwards

Jan 1, 1935

By H. W. Hitzrot

*Original Pages Missing From Book

Jan 5, 1954

By Erik G:Son Odelstjerna

ALTHOUGH the Swedes have not taken as prominent a position in the open-hearth as in the Ressemer industry, the successful development of which in Sweden has been described by Prof. Åkerman, in a paper read before the Institute,? nevertheless our work with the Siemens-Martin method may possess some interest, even for countries outside our own, and especially for the United States, where the charcoaliron industry competes with that of Sweden for the first rank in extent and importance. I take the liberty therefore of giving in

Jan 1, 1895

Jan 1, 1902

By M. G. F. Söhnlein

In the earlier clays, these ores were treated by chloridizing-roasting followed by amalgamation, with satisfactory results, according to the information now available. Material from old tailing dumps from ore treated by this process, which are found at several places in the vicinity of Oruro, seldom contains more than 5 to 6 oz. of silver per ton. As ore with less than 100 oz. per ton was not treated, the extraction of silver must have been good. Reports of the operating companies published about 1890 asserted that over 90 per cent. of the silver was recovered, but in these calculations, as a rule, no allowance was made for silver lost during roasting and the figure referred only to the extraction of silvcr by amalgamation from the roasted ore.

Jan 1, 1921

Jan 1, 1970

By Philip McKenna

WHEN a new material becomes available to industry, it is useful to describe its properties as a guide to its most effective application; and when the new material may be produced in compositions having a series of graded properties, tests to select the combination of properties best adapted for various uses are helpful. The class of materials to be con-sidered in this paper are hard tool materials produced by processes of powder metallurgy from hard carbide constituents and various matrices of iron, nickel or cobalt, or alloys of them with tungsten, or tungsten and carbon. The customary use of carbide hard alloys is for metal-cutting tools; although wire-drawing dies, lathe centers, follow rests, grinding rests, burnishers, rolls, extrusion dies, measuring gauges and micrometers, and a number of other tools are also made with these hard alloys as the essen-tial wear-resisting parts. The properties and tests to be considered are those affecting these uses. In the development of tool, materials since the industrial revolution we have had carbon tool steels, Mushet steel, high-speed steels, stellites, and now cemented carbide compositions. For an understanding of the latter category of materials their properties and uses relative to the older and more familiar tool materials will be considered.

Jan 1, 1938

Jan 3, 1950

By R. S. Lewis

The Utah field to which the name Book Cliffs is applied runs in a northeast direction from Mt. Hilgarde, in Sevier county…

Jan 1, 1915

By L. G. Austin

The procedure for scaling breakage parameters determined in a laboratory mill to values for a full-scale mill is briefly presented. A simulation model of a closed circuit mill also requires a model of residence time distribution, a mass transfer law to predict over-filling as a function of flow rate through the mill, and a model to describe classification action. For fine dry grinding, or viscous slurry grinding, it is necessary to allow for slowing-down of breakage rates for a fine mill charge. Four examples of comparing simulation models to actual plant data are presented. The first is wet grinding of copper ore in normal closed circuit at 50 tph (metric) production, under conditions where the mill does not overfill. The second is the wet grinding of copper ore in reversed closed circuit at production of 87, 102 and 108 tph, with flow through the mill of approximately 150, 200 and 300 tph. The third is dry grinding of coal with a hot air sweeping stream to remove all of the coal as air-borne material, in open and normal closed circuit. The fourth is grinding of cement clinker in a two-compartment, air-swept tube mill in normal closed circuit with two different classifiers, producing 120 tph of 3250 Blaine cement. In all cases the simulated capacities and product size distributions were in reasonable agreement with actual plant performance.

Jan 1, 1984

Jan 1, 1951

America.-Foreman, J. T. Ashland.-Sturdevant, J. C. AItalIa. Henderson, R. M. Bessemer.-Ball, E. M. Maschmeyer, W. L. McKenzie, W. C., Jr. Birmingham.-Abbott, C. E. Aldrich, T. H. Aldrich, T. H., Jr Aufderhaar, H. C. Berg, H. A. Blair, C. S. Bush, M. W. Clark, G. H.

Jan 1, 1923

By Donald E. Crowell

Due to falling metal prices and depletion of ore reserves, lead- zinc mining in the Leadville, Colo., area gradually came to a halt in the 1950's. Exploration work continued, however, and by 1969 sufficient ore had been blocked out to warrant sinking a shaft and erecting a new concentrator to treat 700 tpd. The new shaft and concentrator were to be located in Iowa Gulch several miles east of Leadville at an elevation of 11,100 ft. The Leadville project is a joint venture between Newmont Mining Co. and Asarco, with Asarco being the operator. Design work began in the fall of 1969. Engineering was done by Torkelson Engineering Co. of Salt Lake City in conjunction with the central engineering department of Asarco. The plant was constructed by Stearns-Roger Corp. Construction began in the spring of 1970 and the plant went onstream in April 1971.

Jan 11, 1972

Jan 1, 1951

CONTENTS PAGE World-V. R. Garfias 3 Russia-R. C. Beckstrom 6 Rumania-I. I. Gardescu 11 Germany-W. Kauenhowen 14 France, Italy and Poland-W. P. Haynes 20 Persia-Sir John Cadman 23 Iraq-E. B. Swanson 27 Burma and India-L. D. Stamp 30 Venezuela-H. Sherman 37 Trinidad-H. W. Reid 44 Colombia-O. C. Wheeler 47 Peru-O. B. Hopkins 50 Mexico-V. R. Garfias and R. V. Whetsel 51 Canada-L. C. Snider 55

Jan 1, 1933

Jan 1, 1889

By James E. Little

Of the several extensive deposits of brown iron-ore in Cuba, including those of Mayari and Moa, that of Mayari was the first to be systematically explored, and was selected as the scene of the first operations in the development of this class of ore. Construction-work, begun in the spring of 1907, involved the building of 16 miles of stantlard-gauge railroad and two large double-track inelines, the installation of milling-machinery, a nodulizing-plant, power-plant, shops and shipping-facilities, and the dredging of an extensive basin for deep-draught vessels. Unusual weather-conditions delayed the completion of portions of this work so that the entire plant was not in operation until December, 1900.

Jan 1, 1912

By Richard H. Jahns

Such minerals as beryl, lepidolite, sheet muscovite, spodumene, and tantalite-columbite are obtained chiefly from pegmatite bodies that are internally zoned. As shown by examples of such pegmatites from the Southwestern and Southeastern States during World War II, studies of their internal and external structure have value in prospecting and the planning of exploration, development, and mining.

Jan 1, 1951

Abramovits, Charles, Student. Case School of Applied Science Cleveland, Ohio. '37 Adams, Benjamin C., Jr Address Wanted. '36 Adams, Ernest C., Student, Univ. of Illinois 908 W. Green St., Urbana, Ill. '35 Adams, George H. 4021 Walnut St., Riverside, Calif. '36 Afshar, Hodji Khan ?A. Box 2072, Norman, Okla. '35 Ahlen, Louis S., Student, Univ. of North Dakota Univ. Sta., Grand Forks, N. D. '37 Ahrenholz, Herman William, Jr., Student, Lehigh Univ Bethlehem, Pa. '35 Alger, Robert P., Student, Missouri School of Mines & Met Rolla, Mo. '36 Alkire, Robert L., Student, Univ. of Pittsburgh Pittsburgh, Pa. '37 Alleman, Virgil C., Student, South Dakota School of Mines Rapid City, S.-D. '37 Allen, C. G., Student, Case School of Applied Science Cleveland, Ohio. '37 Allen, Eugene S., Student, Univ. of California Berkeley, Calif. '37 Allen, George W., Student, Michigan College of Min. & Tech Houghton, Mich. '37 Allen, Harry Berkley, Student, Univ. of California Los Angeles, Calif. '37 Allen, Henry, Jr., Student. Univ. of Arizona Sigma Chi House, Tucson. Ariz. '37 Allen, Paul W., Student, Mass. Inst. of Tech Cambridge, Mass. '35 Allen. R. M.. Jr.. Student. Virginia Polytechnic Inst., "G" Co Blacksburg, Va. '35

Jan 1, 1937