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By Charles Pack

Extensive progress has been made in the metallurgy of alloys for die castings. Enthusiastic proponents of some alloys are inclined to make extravagant claims for their materials, which may be justified by physical tests on test bars made from the respective alloys but are seldom justified by the results obtained with commercial die castings made from those alloys. Chemical analysis of the test bars and castings fails to determine the cause of these variations, since they are due to other physical factors entering into the commercial production of die castings. In this paper, an attempt will be made to outline some of the factors in commercial die-casting practice to which these variable results may be attributed, in the hope that the manufacturer of die castings, recognizing the importance of these factors, will devote more attention to them in the design and construction of dies and equipment. In 1914,l the author defined die castings as "metal castings made by forcing molten metal, under pressure, into metallic molds or dies." This definition was given in order to differentiate die castings from other molded metal products such as "permanent-mold" castings, L'slush" castings and similar products that are sometimes erroneously termed die castings. The term "die casting" could be interpreted to include all castings made in metal molds or dies; but since this term, like most of our technical nomenclature, has been developed by commercial practice we must look to this practice for its proper definition. The Germans, with their usual devotion to desecriptive names, have adopted the name of sprilzguss (squirt cast) for die castings. Undoubtedly this name is more descriptive of the die-casting process, where the metal is literally squirted into the die and serves to differentiate this process from other metal mold processes, where the metal is poured into the die. In the earlier paper mentioned, the author also emphasized the fact that the definition given for die castings indicated clearly that the satisfactory operation of the process must comprise three factors, all of which must be considered of vital importance to the successful operation of the die-casting process:

Jan 1, 1931

By Nelson Taylor

WITH the extensive deposits of potash minerals which have been dis-covered in the southwestern states, and their rapid development, a permanent. American supply of potassium compounds is now assured. The 325-year history of the potash industry in this country has been told by H. I. Smith1, of the U.S. Geological Survey, and the more recent activities of the Survey and of American potash companies were described last year by the same author2. In fact, it may be stated that so great is the productive capacity that two mines in New Mexico and one in California are able to supply more than half a million tons of crude and refined salts over and above that produced for agricultural purposes. The era of scarcity has given way to an era of superabundance. This situation makes it desirable for the potash producer to look for other applications for his product, and it is with this in mind that the writer presents some information pertaining to present and possible future uses for potassium compounds in the ceramic industry.

Jan 1, 1936

The Library of the above-named Societies is open from 9 A.M. to 10 P.M., except on holidays. It contains about 70,000 volumes and 90,000 pamphlets, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library, through its Library Service Bureau, can render valuable service through correspondence; letters requesting information will receive especial attention. The Library is prepared to furnish references and photographic copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information on the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral. matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape.

Jan 3, 1917

By S. J. Aparo

After surveying the beneficiation techniques in the Florida phosphate field, it is apparent that optimum beneficiation of this ore is a difficult task. Due to continually changing grade, size distribution and basic nature of the ore, there appears to be no universal technique nor a single reagent entirely satisfactory for achieving optimum metallurgy under these dynamic conditions. Although no major change in the basic flow sheet has been made in the last 20 years, there have been many refinements of the process in recent years which have helped increase production, improve recovery, lower unit cost of operation and make the beneficiation of lower grade deposits economically feasible. Among the significant changes is the use of larger plants and equipment which has helped to increase production significantly. The use of cyclones has facilitated and reduced the cost of slimes removal in these large plants. There have also been several new approaches to the flotation of coarse phosphate that are mentioned in the text of this paper. Lastly, significant improvements have also taken place in the area of flotation reagents.

Jan 1, 1970

YEAR OF ELECTION 1913. FRANK DAWSON ADAMS Montreal, Canada. 1921. WILLIAM CUTHBERT BLACKETT Sacriston, Durham, England. 1923. GELASIO CAETANI Rome, Italy. 1929. TAKUMA DAN Tokyo, Japan. 1920. HENRY STURGIS DRINKER Merion Station, Pa. 1922. FEDERICO GIOLITTI Torino, Italy. 1906. SIR ROBERT A. HADFIELD London, England. 1928. JOHN HAYS HAMMOND New York, N. Y. 1928. WILLIAM BOYCE THOMPSON Yonkers, N. Y. 1921. FRANK WILLIAM HARBORD London, England. 1917. HERBERT HOOVER Washington, D. C. 1905. HENRI LECHATELIER Paris, France. 1921. C. MCDERMID London, England. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico. 1909. ALEXANDRE POURCEL Paris, France. 1911. ROBERT H. RICHARDS Cambridge, Mass.

Jan 1, 1923

By E. E. Donath, W. L. Crentz, J. D. Doherty

The principal washing problems in preparing coal for the synthetic fuel industry may be stated as: (1) ash removal for the Bergius process; and (2) sulphur removal for the Fischer-Tropsch process. A study is made of the effect of ash on oil losses during the elimination of the nonliquefiable portions of the coal in the hydrogenation process. The oil loss increases with ash content and results in increased consumption of coal, hydrogen, and power.

Jan 4, 1950

By A. A. Berk

LAGGING technology and the slow spread of in- formation have been the chief obstacles to wide- spread participation in minimizing the industrial pollution load. These obstacles can be conquered by fact finding and applied research. There are three aspects to the problem of waterborne mineral waste: to minimize the amount being thrown away, to select a predisposal treatment, and to use the products or dispose of them.

Jan 7, 1957

MISSOURI SCHOOL OF MINES On the tenth of January, 1919, a meeting was held by the juniors and seniors for the purpose of reorganizing the Missouri Mining Association. The reorganization was brought about in this manner because at that time there were no old members left in school. At that meeting, the following officers were elected for the remainder of the year: Gerald F. Rackett, president, Harland H. Hoppock, Secretary. The Association has held several interesting meetings and is arranging interesting programs for some to be held in the future. At present the Association has thirty-four members. H. H. HOPPOCK, Secretary.

Jan 5, 1919

William B. Phillips, Birmingham, Ala.: The analysis of Pratt coal made by myself, and given by Mr. Ormsbee in his paper (p. 113), is likely to mislead the reader as to the real nature of this coal. It represents the very purest coal that I have been able to get, and does not represent the average composition of the lump-coal as prepared for market. I wish it were true that the coal had no more than 2.50 ash and 0.83 sulphur. The analysis of McCalley is nearer the real figures than any of the others. There is no use in giving an

Jan 1, 1896

By J. W. Lewis

This review covers that portion of the area between the Llano mountains and the Red River which lies between Fort Worth and Abilene. The counties and fields included are listed in Tables 1 and 2. During 1929 there was a marked lull in both prospecting and development in this part of Texas. Archer, Coleman, Cooke, Wilbarger and Young were the counties most active. The total gross production of the year was 52,611,000 bbl., 3 per cent. more than for 1928. The production of the Coleman, Cooke-

Jan 1, 1930

By Ira B. Joralemon

INDIVIDUALS and small companies have discovered and brought into production the mining districts of the United States. Hardly an exception comes to mind, save for the disseminated copper properties and the great iron mines. In spite of this fine record that has made possible the industrial greatness of the country, mining by small companies and by individuals has become a vanishing phenomenon. In Nevada, the lair of rugged individualism, there are fewer operating mines and fewer miners than at any time since the 1860's. The situation in other states is nearly as desperate.

Jan 8, 1950

By John V. Beall

New York was bathed in pale winter sunshine and, surprisingly, coatless weather. The time was the AIME Centennial and 100th Annual Meeting. From advance peeks into the fabulous schedule of events we were well aware that the Centennial Committee, New York Host Section and AIME staff' had pulled out all the stops, laying on the best of everything, but the weather gimmick was the frosting on the cake. The Formal Greetings Session on the first morning, Joe Alford confided, was the greatest AIME experience of his life. Without doubt the honor bestowed on AIME by the greetings and felicitations of the presidents of the world's leading professional engineering societies was the greatest moment in AIME history-save one. That one exception was in 1928, when 1920 AIME President Herbert C. Hoover was elected President of the United States.

Jan 1, 1971

By S. R. Krogh, T. O. Olsen

Analytical expressions for the breakage rate as functions of mill charge, mill speed, particle size, ball diameter, and ball load are derived, using idealized models for probability of breakage (Gaudin and Meloy), energy distribution (Mempel), and arithmetic mean of effective ball energy (Langemanns). Computational results using the theoretical equations are compared to experiments. The equations enable simulation of ball mill grinding at different grinding conditions.

Jan 1, 1973

Jan 1, 1914

By R. J. Blackwell

No. 576.-Graduate mining engineer, married, 32 years of age. Have had 10 years' experience in mining from position of mucker to that of general superintendent. For past four years have been in Copper River District of Alaska as mining engineer, and superintendent of gold and copper mines. Desire position in U. S. Best of reference. No. 577.-Member, technical, age 27, married. Open for engagement. Past year in war mineral field work, operation and production. Ten years thorough experience in both subordinate and executive positions, gold, silver and copper in the U. S., Mexico and South America. Devel-

Jan 5, 1919

By James R. Garvey

Coal reserves of the United States are enormous. Considered on the basis of proven reserves, and compared with reserves of other fuels, coal constitutes 88% of the proven recoverable energy resources of the nation. That includes oil, natural gas, oil shale and uranium used in burner reactors. Considered on the basis of "ultimate recoverable reserves", that is, those resources which can be extracted with improved technology and at somewhat higher costs and including those resources of all fuels not yet found but believed to be waiting discovery, coal still accounts for 75 % of the national total. In the U.S. hydrocarbon economy about 76% of the total energy needs are supplied by petroleum and natural gas and about 20% by coal. Domestic resources of oil and gas are running dangerously low, and assuming a continued hydrocarbon economy, the 20% supplied by coal may increase dramatically. Nearly a quarter of the petroleum consumed in the U.S. is imported. Natural gas is in shorter supply than petroleum and the problems of its importation seem at least as difficult as those of oil.

Jan 6, 1972

By V. C. Allen

THE Tri-State Zinc, Inc., Galena, Ill., was confronted with the problem of securing ore from a deposit because the hoisting shaft was several thousand feet from the mill. The orebody is several thousand feet long, averaging 200 ft in width and 60 ft in height and opened up by vertical shafts some 300 ft deep. Mining is by the room-and-pillar method. During the initial operation the ore was loaded by conventional electric 1/2 -yd boom-and-dipper shovels and hauled to the shaft by 8-ton diesel trucks. This underground ore loading and hauling was well adapted to the conditions and productive of low costs per ton. However, with the mill situated as mentioned, a triple handling of all broken rock was necessary: 1-from the stope to the shaft by truck, 2-up the shaft by skip or can into the surface hopper, and 3-by truck from the surface hopper to the crushing plant at the mill. In addition to the repeated handling, serious troubles were encountered during the winter because of freezing in the shaft hopper.

Jan 6, 1951

By H. I. Aaronson

THE TTT-curve for the beginning of transformation in hypoeutectoid steels containing appreciable amounts of relatively strong carbide-forming alloying elements often exhibits a "bay" at intermediate temperatures. In many of these steels, proeutectoid ferrite is the initial product of the decomposition of austenite not only at temperatures above the bay but also in an appreciable temperature range below the region of the bay. Hultgren has postulated that ferrite formed above the bay, termed "orthoferrite", contains the equilibrium concentration of alloying element at temperatures above the eutectoid range, and the extrapolated metastable equilibrium concentration at lower temperatures. The ferrite formed below the bay, on the other hand, termed "paraferrite", was assumed to inherit completely the bulk alloy content of the austenite without regard for the compositional requirements of equilibrium. As shown schematically in Fig. 1, the two types of ferrite were taken to have different Ae3 temperatures and different C-curves on a TTT-diagram. Their different kinetic behaviors were thus considered responsible for the bay in the TTT-curve for the proeutectoid ferrite reaction in this type of alloy steel.

Jan 1, 1962

By H. A. Bauman, T. S. Spicer, C. C. Wright

Experimental data are presented showing the influence of size consist and firing rate upon the performance of bituminous coal-fired, single-retort, industrial underfeed stokers. Size segregation, degradation, and distributor data are also included. The conclusion is reached that size consist of the fuel as fired, is a critical factor in its performance on this class of equipment.

Jan 2, 1950