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By M. L. Fuller

MOST commercial alloys undergo changes in phase composition after casting. This is a natural result of the fact that the alloys are not in a state of phase equilibrium as cast and phase changes will therefore take place, with more or less rapidity, in an attempt to attain equilibrium. The practical aspect of aging in zinc-alloy die castings concerns the changes in physical properties and in dimensions that may accompany aging phase changes. Harmful alterations have been reduced to a minimum and zinc-alloy die castings are being produced today that are so stable with respect to dimensions and physical properties that they are entirely suitable for most practical purposes1. In the first paper' of this series, and in this paper, aging phase changes of zinc alloy die castings have been investigated and the possible influence of these changes on dimensional changes of the castings has been evalu-ated and compared with the dimensional changes actually experienced. The change of dimensions has been selected for practical comparison in these papers because the effect of phase changes on the dimensions of a casting is directly calculable; from X-ray crystal-analysis data of the phase structure. The die-casting alloys considered contain, in addition to zinc, 4 per cent of aluminum, about 0.03 per cent magnesium, and from 0 to 3 per cent of copper. It was shown in the former paper that the eutectoidal decomposition of the beta aluminum-zinc phase, while intrinsically capable of causing a considerable shrinkage, can have very little effect on the observed shrinkage of die castings because it takes place within a few days of aging, whereas the observed shrinkage continues for five weeks. It was therefore concluded that the other existing phase change,

Jan 1, 1936

By Donald L. Colwell

THIS is a metallurgical war. More than ever before, the mechanized forces and the air-borne warfare are deciding campaigns. Both of these are primarily dependent upon metals. There are two ways of increasing the effective supply of these metals when the demand is greater than the total over-all supply. The American custom, when a shortage of anything develops, is to get more. In the case of some nonferrous metals this has been done. For example, our potential peak output of magnesium will be almost one hundred times the prewar production. Output of aluminun has also been tremendously increased, and production of other metals is being stimulated by every possible means. Our enemies, however, have another successful method of increasing the effective supply of a material, and that is, to eliminate entirely all nonessential uses, and also to use, in essential applications, alternate materials wherever possible. Sometimes, ersatz material is inferior to the original, and consequently does not do the job as well. Often, however, it has been found superior, and many substitute items are now being used both by industry and by the military which will continue even when the original material again becomes available.

Jan 1, 1943

By J. C. Boswell, J. D. Crawford

IN addition to its base-metal and coal mining operations, the United States Smelting Refining and Mining Company has, for the past quarter century, been one of the few large American mining companies interested in dredging. Its activities in this field are confined to gold, and to Alaska, but it is the largest operator in that territory, with twelve huge dredges available to work during the summer on the frozen ancient beach sands at Nome and the gravels of Fairbanks. These operations will be described separately.

Jan 1, 1948

By HENRY M. HOWEL

1. Introduction.-The first part of this papers treats of the causes and the restraining of piping in steel ingots; the second& considers the causes and the restraining of -segregation; and the third proposes certain precautions in engineering specifications concerning these two defects. Into their causes I have looked carefully, with the purpose of arriving at rational methods of restraining them, and at efficient ways of detecting. and measuring the harm which they cause, so as to benefit the public by reducing this harm at once effectively and with the least expense to the manufacturer, and therefore in the end with the least expense to the consumer. In Part I., I infer that the pipe is chiefly due to what I, call the virtual expansion of the outer walls of the ingot in the early part of the freezing. I find that the upper and smooth-faced part of the pipe probably forms while the interior is still molten, but that the lower, steep, and crystal-faced part probably forms in metal which is already firm. Of the five causes which may co-operate to limit the depth of the pipe, I find that three-blow-holes, sagging, and the progress of freezing from below upwards-are usually effective. I find that the pipe may be lessened by casting (1) in wide ingots,; (2) in sand molds, especially if these are pre-heated (this is rarely expedient); (3) at the tops instead of at the bottom; (4) slowly; (5) and with the large end up; (6) by the use of a sinking-head or other means of retarding the cooling of the top; (7) by permitting blow-holes to form; and (8) by liquid compression.) Most of these I consider in some detail, and in particular I dwell on the advantages of casting with the large end up, and I propose certain administrative arrangements to permit this.

Mar 1, 1907

By AIME AIME

THE program of government drilling, conducted jointly by the U. S. Geological Survey and the Bureau of Mines, has demonstrated the presence in Texas and New Mexico of potash-bearing beds of considerable importance. Information regarding the ex- tent and location of the potash deposits as presented at the non-metallic sessions was of great interest to many engineers. These subjects will be covered in greater detail in later paragraphs. The first session, with about 50 in attendance, convened at 10 a.m. on Feb. 18, with Oliver Bowles, chair- man of the Committee on Non-Metallic Minerals, pre- siding. The first paper was on "Soapstone Mining In Virginia," presented by C. W. Ryan of Lynchburg, Va. The nature and extent of the soapstone deposits of Nelson County were described in some detail. In origin, the soapstone is undoubtedly related to a basic peridotite rock though its mode of formation is some- what uncertain. This main soapstone deposit occurs in three veins, the western, middle, and eastern, the middle vein being of greatest economic importance. Methods of stripping, quarrying and milling the rock were described and the uses of soapstone were enum- erated. In discussing this paper, C. P. Berkey, of Co- lumbia University strongly favored the theory of igneous origin of the soapstone and the need for further detailed geological study. J. L. Gillson of Cambridge, Mass., stated that the Vermont and New York talc deposits were always associated with characteristic minerals, such as, a chlorite of one particular variety, siderite, amphibole, magnetite, and biotite. C. H. Behre of Cincinnati, Ohio, raised the question of parallelism in the soapstone structure and Mr. Ryan stated that such parallelism was in evidence in some parts of the deposits. H. A. Wheeler of St. Louis, Mo., also took 'part in the discussion.

Jan 1, 1929

By AIME AIME

NAPOLEON'S dictum that an Army travels on its stomach has not changed in this present war, but the things an Army's stomach calls for would be more than strange to Napoleon. Today one of the main articles of diet for the mechanized army is oil and gasoline, and the chief and most efficient source of 'apply overland is the pipe line. It was a flexible 4-in. pipe line that supplied the voracious appetite of tanks, trucks, jeeps, and planes across the North African desert. and it is the 1800-mile pipe line from Calcutta to Kunming, Yunnan Province in China, the longest in the world, that supplied oil and 100-octane gas for the trucks, tanks, Jeeps, and planes fighting on the Assam-Burma-China front in recent months. Completion of this approximately 1800-mile pipe line to China over rivers that had never been bridged, over hill that towered 9000 ft., and over swamps

Jan 1, 1945

By J. J. Bowman, E. H. Dix

A LACK of experimental data illustrating the effect of composition, particularly in respect to impurities, on the mechanical properties and corrosion resistance of aluminum-alloy die castings induced the authors and their associates to undertake a limited study of these relations. A number of commercial alloys and several experimental variations of a commercial alloy were used for the investigation. Mechanical property, growth, steam, paraffin, salt spray and atmospheric exposure tests were employed. This paper deals with the more accelerated tests and the results they have produced. It is concluded that a high-silicon alloy with all impurities except iron strictly limited to small amounts will develop an excellent resistance to corrosion and retain satisfactory mechanical properties and casting characteristics. As a direct result of this investigation an alloy of this character with superior corrosion resistance is now available commercially. In general, copper increases the strength and decreases the elongation and corrosion resistance. Tin reduces the mechanical properties and the resistance to corrosion. Iron reduces the elongation and, if excessively high, may adversely affect the tensile strength. Even excessively high iron contents do not affect the corrosion resistance, which is fortunate for the die caster as it is this element that is the most difficult to control. Nickel and zinc in limited amounts do not seem to affect the properties or corrosion resistance of at least the high-silicon alloy. Growth tests have confirmed the previous common belief that dimensional changes under either dry or wet conditions at 100° C. are too small to be of practical importance.

Jan 1, 1935

By John A. Mathews

RESEARCH in the steel industry, as in other lines of manufacturing, has for its principal purpose the increasing of profits. That is what manufacturing companies are for, and all departments of the organization must be so coordinated as to lead to profitable operation. To divide a payroll into productive and non-productive labor is misleading. Productive labor, in fact, is necessary labor, and non- productive labor is the labor we can get along without. One might as well say that the steering wheel is not a part of an automobile as to say that the directing minds of an industry are non-productive. Legitimate manufacturing profits in a steel company or any other company are the reward that the public pays for service rendered or risk taken. The desire for profits is the impelling motive that leads investors .to take risks and build up industries that give employment to others. Every department of a company, be it executive, manufacturing, financial, sales, or research, must contribute to the one end which brings success-profits.

Jan 1, 1921

By AIME AIME

T HE 133rd meeting of the A. I. M. E., opening in New York on Feb. 15, promises to be as successful technically and socially as any in the past. The papers submitted for the various technical sessions are unusually excellent and insure something of interest to every group. Tentative programs have already been issued, and a concise resume of the various sessions, arranged chronologically, appears on page 48. Among the many interesting technical sessions arranged, attention is directed to those of the Petroleum Division, embracing the Symposium on Production that has come to be an annual feature, and new ones on refining practice, transportation and economics. The Institute of Metals program is similarly comprehensive. It includes 15 papers, 8 on copper, 4 on aluminum and its alloys, and one each on magnesium, lead, and fatigue of metals. The Coal Committee offers as a leading contribution its report, prepared under the direction of H. N. Eavenson, giving a new analysis of the capacity of the mines and a comparison of coal with other industries. This will be supplemented by a number of other papers of especial interest to operating men, among which are "Data on Use of Loading Machines in Bituminous Mines," by Graham Bright; "Evaluation of Coal," by R. H. Sweetser; "Selection of Coals for the Manufacture of Coke," by H. J. Rose; and "Relation of Origin and State of Carbonization of Coal to Problems of Low Temperature Carbonization," by S. W. Parr. The Iron and Steel Committee has scheduled seven papers, and there will be a special session on open-hearth practice, in which will be presented the first results of the two conferences, held by the sub- committee at Pittsburgh and Cleveland. A symposium on molding sands will be a special feature of the session on non-metallics.

Jan 1, 1926

By A. B. Stickney

UPWARDS of 200,000 engineers in this country are sufficiently interested in engineering as a profession to have joined a society, but not over 10% of them belong to any one society. There is a widely-felt need of an over-all organization of all the societies to act as spokesman for all engineers on matters of common concern. On a local basis, over 100,000 engineers in 35 metropolitan areas have organized themselves into local councils, and are doing an effective job of intersocietal co-operation within their sphere of activity. In the last few years much has been said and written about a similar organization on a national scale. Everybody wants iteverybody is talking about it-it's in the air-it's coming-it's inevitable. Although it is no longer necessary to talk about why or whether there should be such an organization, there is no such unanimity about what it should be like. This paper outlines a proposed organization by answering four questions-who, how, what, and who will pay for it.

Jan 1, 1946

By S. F. Emmons

Jan 1, 1899

By H Haas

H. HAAS, San Francisco, Cal. (communication to the Secretary?). -Fig. 1 plainly shows that the comparison of the steam-turbine and Diesel-engine plants was made on a basis of 6,000 kw. continuous operating load. The tabulation of costs for an 8,000-kw. load is merely done to show the relation of increased output on' the unit power costs. Both plants would sacrifice their reserve capacity, which is to insure continuous operation, if operated to generate 8,000 kw. continuously; unless Mr. Hawkins advocates the operation of one of the turbines at 33.33 per cent. overload, retaining the other as a standby, which, besides overtaxing the turbine, results in a great loss of efficiency. It would he well for Mr. Hawkins to qualify certain of his statements. Thus, under the caption "Diesel Engines, Selection of Units," he says that "two of the largest Diesel-engine builders take the position that, in the present state of the art, they would not attempt to put out units over 1,000 kw.;" he should qualify it by saving that "two of the largest American Diesel-engine builders take the position that, in the present state of the art in the United States, they would not attempt to put out units over 1,000 kw." The reason that American manufacturers restrict themselves at present to units of that size is to be found not so much in a lack of experience in building large units as in a lack of a sufficient, demand for them in the United States to justify the heavy capital outlay connected with the development of such engines. There are relatively few localities in the United States where fuel prices are as high as they are in the Southwest, and regions of high fuel prices are sparsely settled and have a very limited demand for power. Where low fuel prices obtain, steam turbines are active competitors of Diesel engines for large power plants, particularly when the station load factor is low. As most of the American manufacturers of Diesel engines work under license agreements with European manufacturers, which limit their market to the United States and its possessions and Canada, a further limitation is imposed upon them, leaving to European firms practically the entire world as a market.

Jan 5, 1917

By F. C. Foshag, P. E. Wingrove

The Kayford, Boone and Nicholas Division of Bethlehem Mines Corp. operates a modern coal preparation plant in Van, WV. Since start-up of the Van plant in 1976 until the summer of 1980, the refuse handling system proved to be a costly maintenance problem and a material handling bottleneck. During the 1980 two-week miners' vacation, the original system - which included two screw conveyors and a drag conveyor - was replaced by an installation using two Flexowall steep angle belt conveyors. This paper describes the technical and economic analysis that led to the new installation and reviews its first year operating performance.

Jan 1, 1983

By Stanley J. LeFond

Brazil is one of the most outstanding examples of economic development of our time. Its amazing growth record is substantiated by a GNP which has increased at an average rate of 92% for the period 1968-1970 and estimates for 1971 range from 11.7-12.5%. Hence, this growth, coupled with a more relaxed attitude of the Brazilian government towards foreign participation in business opportunities and the remittance of profits out of the country, has caused many exploration companies to reevaluate the potential of Brazil. Despite recent press notices and publicity, Brazil is still not a mining country in the tradition of Canada or Australia. It is still basically an agriculture and manufacturing country.

Jan 11, 1973

By Frederic P. Dewey

This old and well-known method of determining silver is, in bullion work, so far superior to the furnace-assay that it is looked upon with reverential awe by many, if not by most, users, and its ease of execution, with proper equipment, commends it highly where much commercial bullion work on silver is required. The method is so thoroughly well known that a description of it here may seem to be unnecessary, but many thousands of determinations are annually made by it in the U. S. Mint Service and its practice is there reduced to an art. This is necessary both for the sake of economy of time, and because high-grade work with it requires constant practice. It is useless for a person who uses it only occasionally to expect to attain high accuracy with it, without spending more time upon a detemination than is warranted in a busy commercial laboratory. It is always employed in the Mint service whenever possible, but its chief field is in the determination of silver in standard silver (ingots and coin), which is 900 fine in silver and 100 fine in copper, and I shall first briefly outline its use on this metal and then take up various points in detail, especially as related to the accuracy of the results obtained. For this determination 1,115 mg. of standard metal are weighed and transferred to a glass-stoppered bottle, the metal is dissolved in nitric acid, and 100 cc. of a standard solution of NaCl run in. The bottle is then vigorously shaken and a measured portion of a decimal salt solution added, and again shaken, if necessary. These operations are repeated until the silver is precipitated. Standard metal being 900 fine, 1,115 mg. should carry 1,003.5 mg. of silver, which is a convenient figure to work with.

Jan 1, 1914

By T. A. Rickard

The key-note of good writing, as of good manners, is B natural. Sincerity is the first requisite for effective writing. When a man says what he knows or believes, he is likely to be interesting, because each human being possesses an individuality, a point of view, or a range of sympathy that makes him different from his fellows. To say or to write what you do no6 think, for the mere sake of talking or writing, is a verbal exercise that must be performed with extraordinary skill if it is to be attractive. Affectations are rarely attractive, rarely effective. To be natural is to be yourself, not a poseur; to give the reader the best of yourself, instead of re-warming the baked meats of yesterday. Quotations-which are second-hand thoughts-will serve occasionally when the thing you want to say has been said so well by another that it would be waste of energy to try to say it better; but, as a rule, the utterance of the writer himself is more interesting than the quotation, because the writer brings something of himself to bear on the subject, and for the moment is more in touch with the reader than any dear departed author. Therefore, say things as best you can in your own way, neither in borrowed words nor in the phraseology that mimics another. Write as if you were speaking to a person whom you desire to persuade or convince. You will then write better than you speak, because, in the first place, you can be more deliberate, and, secondly, you can revise what you have written. Speaking and writing are similar mental acts, with a difference: the difference between eating food raw and eating it cooked. Some kinds of food gain nothing by being cooked; likewise some kinds of utterance are not bettered by being written down first; but most expressions of thought, especially

Jan 1, 1931

By R. E. Allen

THERE was once a time when a practical oil man would appraise or buy a producing property on the basis of from $200 to $500 per barrel of average daily settled production. Curtailment-has, for the present at least, caused a virtual abandonment of the "barrel -of settled production" as a yardstick of, oil property value and in its place has come the "barrel of allowable production," which, although an artificial thing, is nevertheless now the principal factor governing the rate of ?pay out? or investment return. The potential production of a well, settled or otherwise, is of less importance in determining the present worth of a well than is the rate at which it may be produced. Speaking only of true potential for the moment, it is obvious that of two similar wells having the same potential, the one having the highest rate of allowable production would be worth proportionately more than the one of lesser allowable. The discount factor for deferred return and risk can easily vary the present values of the two wells by as much as 20 per cent when allowable rates are not greatly different.

Jan 1, 1934

By K. H. Heino

Two 200 T/da Lurgi Turbulent Layer fluid-bed roasters have been in operation at Canadian Electrolytic Zinc Limited since 1966. Zinc concentrate containing 52-54% Zn, 9-11% Fe,31-33% S is treated to produce calcine containing 60-62% Zn,10-12% Fe, .l-.3% S as sulphide and .8-1.2% S as sulphate. Each roaster train comprises a waste heat boiler, two cyclones in parallel and a two-field electrostatic precipitator. Distribution of calcine collected is 10-15 percent from bed overflow, 55-65 percent from boilers, 20-25 percent from cyclones and 2-6 percent from precipitators. A Monsanto designed contact plant produces acid at a rated capacity of 365 T/da (100% H2304 basis) from roaster gases diluted to 7.0-7.5% S02. The process steps are gas cleaning and cooling by weak acid scrubbing, acid mist removal in electrostatic precipitators, gas drying in 93.5-96.5% H2304, conversion of sulphur dioxide to sulphur trioxide in a four-pass converter containing vanadium pentoxide catalyst, and absorption of the sulphur trioxide in 98.1-98.3% H2S04. Product acid is 93.2% H2S04. Conversion efficiency is 97-98 percent and overall sulphur recovery from concentrate is 87-90 percent. The adjacent fertilizer plant has a capacity of 135 T/da of P205. The products are 54 percent phosphoric acid, run-of-pile triple superphosphate, and diammonium phosphate. The plant is of Ugine-Kuhlman design and consists of an air-cooled multiple tank reactor, a tilting pan filter, and a forced circultation vacuum evaporator. Triple superphosphate is made on a continuous belt and partially cured in a rotary dryer. Diammonium phosphate is produced by ammoniating phosphoric acid in a single stage reactor. The slurry of ammonium phosphate is granulated in a blunger and dried.

Jan 1, 1970

By Leon Borgman, Michael P. Lipkewich

Orebodies at or near the surface are generally amenable to open pit mining. The development of a mining program involves designing an ultimate pit and a production schedule. This pit maximizes total profit while the production schedule maximize6 the present value of the property. Optimum pit limits can be approximated by two-and three-dimensional numerical techniques. These techniques presuppose that the mineralized area has been sufficiently sampled to allow a reasonably accurate prediction of grade at any spatial location.

Jan 1, 1969

By Paul E. Melancon, Vincent C. Kelley, Dale F. Kittel

Uranium of the Grants region occurs predominantly in continental sandstones of the upper part of the Jurassic Morrison Formation, but significant lesser deposits are found in limestone of the Jurassic Todilto Formation and in black shale of the Cretaceous Dakota Formation. The deposits are disseminations that form runs ranging from a few hundred tons to several million tons. The ore consists mainly of uraninite, uraniferous carbonaceous material, coffinite, and such secondary oxidized minerals at tyuyamunite, carnotite, and uranophane. In sandstone, the ore runs were locallized by mudstone, interstitial carbonaceous material, and primary sand channel trends. In limestone, ore deposition was related to folds and fracture zones. The great bulk of production has come from the Ambrosia Lake mines in the Grants district and the Jackpile and Paguate mines in the Laguna district. The ores, which generally have been 0.20 to 0.30 per cent U3O8, are treated at mills operated by Kerr-McGee Corporation, Homestake-Sapin Partners, and The Anaconda Company, all in the Grants district. In 14·years after discovery in 1950, the deposits had yielded concentrates valued in excess of $800,000,000. Since deposition of the Jurassic host rocks, a geologic history involving tilting, faulting, erosion, changing ground-water environments, and oxidation has considerably influenced the existence and character of the deposits. It is evident that their ongm is not simple. However, a degree of agreement appears probable for a pre-Dakota age for the original ore runs, and, at Ambrosia Lake, two principal stages of ore formation, separated by Laramide faulting, are recognized. All earlier ores have been modified by Quaternary oxidation, solution, and enrichment during which time much secondary tyuyamunite, metatyuyamunite, carnotite were formed.

Jan 1, 1968