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Jan 1, 1938

Jan 1, 1920

By O. W. Walvoord

ONE particular plant has been chosen to illustrate the various factors in mill design. The problems are general in nature and with various modifications are met in the design of most milling plants. Literature on modern mill design is not extensive and certainly has not kept pace with the rapid advancement in the art of ore beneficiation. Much remains to be investigated, and continued vigilance is required to give the operator and the metallurgist the best layout to meet the industry's changing requirements. The Humboldt project, a joint venture of the Cleveland-Cliffs Iron Co. and the Ford Motor Co., involves an iron ore flotation plant near the town of Humboldt, on the Marquette range of the Michigan Upper Peninsula. A crushing plant, designed for an ultimate capacity of 720 long tons per hr, is followed by a first mill unit of 70 long tons per hr. Future mill units are planned to bring the total mill capacity to 5000 long tons per 24 hr.

Jan 1, 1954

Jan 1, 1951

Jan 1, 1951

By B. Misra, N. Brook

A new method of determining a "Rock Impact Hardness Number" by comminuting cylindrical specimens in a "Syskov" mortar is proposed. The method of finding Protodyakonov Number by the stamp-mill method was first examined, and the effect of initial size of specimen thoroughly investigated. A method of determining the correct number of blows to use in a test is developed and the inaccuracies involved in the original method, which stem from the measurement of a volume of fines, are avoided by using mass measurements. A graph of percentage fines below 50µtm and number of blows is statistically examined to obtain an accurate estimate of the number of blows to produce 25% fines, from regular initial specimens. This number was defined as the "Rock Impact Hardness Number". The effect of specimen size on this strength index was investigated. A comparison was made between this method of determining rock strength, and a 'field' method using irregular specimens.

Jan 1, 1971

By Joseph B. Umpleby

WHEN the Cushing field flooded the oil market in 1914 and 1915 with a daily output equal to nearly one-third of the world's production, the situation was soon corrected by increased consumption, and the price of crude oil rose from 45 c. per barrel in, February 1915 to $1.10 in December of the same year-the highest price paid in the Mid-Continent field up to that time. The intensive search for oil during the following seven years failed to disclose a single new ,field equal to Cushing, and many observers concluded that the rapidly increasing number of wells contributing to the world's output, each declining roughly 20 per cent. a year, combined with the rapidly increasing con¬sumption of petroleum, made it highly improbable that any field would; be found again sufficiently large to seri¬ously affect the oil market. That seven exceptional fields should then be discovered simultaneously is a remarkable coincidence. Long Beach, Santa Fe Springs, and Powell, each exceeded Cushing in daily output and reached the apex of their production during a year when Burbank, Tonkawa, - Smackover and Huntington Beach each contributed several times the daily output of the average new pool. This unexpected and tremendous flood of flush production could only have the effect of depressing price and greatly adding to stocks throughout the country. It was particularly depressing in the Mid-Continent as the new oil from California proved of attractive refining grade and because of cheap transportation by water easily undersold Oklahoma crude in the eastern markets.

Jan 1, 1924

By H. M. Zoerb

Based on the belief that operating details are a definite contributing factor to major economies, this paper traces the development of crushing cavity design in Symons cone crushers to attain maximum liner utilization. Wear rates are analyzed and compared in this presentation and drawings illustrate succeeding design changes.

Jan 6, 1953

By Alan B. Nicol, W. T. Parry

The outcome of these tests has been twofold. They have served to demonstrate that the tiltmeter is a useful and dependable instrument which could prove to be of significant value in reaching the goals of landslide prediction and control, and they have raised a good many more questions about the mechanism of slides than they have answered. It seems likely that many of the old concepts and assumptions will be modified or discarded as more knowledge of actual field phenomenon is gained. Safety and economy are paramount concerns in determining slope stability. These two considerations govern the feasibility and character of slope construction from start to finish.

Jan 1, 1970

By Blair R. Benner, Ronald J. Roman

The rate of acid leaching of malachite from a sandstone ore was shown to be controlled by the diffusion of H+ ions through the host rock. The kinetics of the reaction can be expressed by a shrinking core model. Equations for calculating effective diffusivities from an "infinite" slab and a cylindrical core were derived. The effective diffusivity, of H+ ions in a sandstone ore was measured.

Jan 1, 1975

By Kirby D. Mellegard, Ralph A. Wagner, Paul E. Senseny

Six creep laws for salt, each fitted to the same laboratory data base, are used in a numerical model of the deformation of an opening in salt to determine the influence of creep law form on the predicted closures. Results show that predicted closures can be very sensitive to the functional form of the creep law chosen to model the laboratory data.

Jan 1, 1982

University of Alabama-University, Alabama, Mining and Metallurgical Society, William L Mason University of Alaska-College, Alaska, Mining Society of the University of Alaska, E H Beistline University of Arizona-Tucson, Arizona, Miners Society, S L Smith Birmingham-Southern College-Birmingham, Alabama, Pick and Hammer Club, Daniel D Arden University of California-Berkeley, California, Mineral Technology Association, Jack Washburn Carnegie Institute of Technology-Pittsburgh, Pennsylvania, The Metals Club, Gerhard Derge Case Institute of Technology-Cleveland, Ohio, Case Metallurgical Engineering Society, Robert F Hehemann City College of New York-New York, New York, CCNY Student Chapter AIME, Daniel T O'Connell

Jan 1, 1957

By John S. Alexander

THE typical block coal of the Brazil (Indiana) District differs in chemical composition but little from the coking coals of Western Pennsylvania. The physical difference, however, is quite marked ; the latter has a cuboid structure made up of bibuminous particles lying against each other, so that under the action of heat fusion through- out the mass readily takes place, while block coal is formed of alternate layem of rich bituminous matter and a charcoal-like substance, which is not only very slow of combustion, but so retards the transmission of heat that agglutination is prevented, and the coal burns away layer by layer, retaining its form until consumed. This property permits the use of raw block con1 in the furnace but theo-

Jan 1, 1876

By B. H. Mot

Underground water has been one of the greatest problems in sinking mine shafts, sealing existing shafts, and driving headings under streams. In the preparation of a proposed shaft or existing shafts for elimination of water leakage, advances have been brought about through the use of a controlled grouting method. The modern method to divert water from proposed shaft sites is known to us as pre-grouting, and from existing shafts, as controlled pressure grouting. This method involves the solidification of the surface and rock by the injection of a liquid mixture of

Jan 1, 1949

By Sebastian Paul Musco

The importance of the recovery of precious metals, specifically platinum group metals, was recently expressed by Robert McNamara, former head of the World Bank, who stated that the United States should stockpile strategic metals. More than 90% of the platinum metals are imported into the United States from South Africa and Russia. Mr. McNamara's concern is based on the possibility of a disruption of obtaining these metals due to any racial unrest in South Africa and a renewal of the Cold War with Russia. The United States has a platinum mine from coast to coast. Since 1974, the automotive industry has consumed 3 million ounces of platinum and palladium, and the recovery of these metals from auto catalyst converters is estimated to be 300,000 ounces of platinum per year. This would make the United States the 4th largest producer in the world.

Jan 1, 1984

By Daniel C. McLean

Copper concentrates produced by many operations in the United States and South America contain chalcocite (79.9% Cu) as a major component, yet the grades of these concentrates rarely exceed 25 to 28% Cu. Mineralogical studies made by E.P. Cadwell indicated that the low grades were caused by dilution by pyrite rimmed with secondary chalcocite. Laboratory and plant tests proved that concentrates could be significantly upgraded by using a simple, low cost cyanide leaching technique to dissolve the rims and reject the pyrite. The many advantages of this new procedure are cited and the process steps and a typical flowsheet are described.

Jan 1, 1984

Jan 1, 1942

Jan 1, 1900

Jan 1, 1887

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Jan 1, 1942