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By Samuel S. Wyer

THE installation of the gas-producer power-plant in America has been so unusual that all engineers have viewed it with in¬terest; a large majority, however, regard it with a lack of con-fidence and many with positive distrust. Despite the fact that European engineers have usually been less inclined to take the initiative along experimental lines than are Americans, they have, nevertheless, developed the gas-producer plant to a very high state of efficiency to which they were forced by the neces¬sity of economy in fuel-consumption. The gas-producer power-plant is so common in Europe that engineers as well as the general public regard it with the same degree of confidence that is now universally placed in steam¬plants. Gas-engines, both small and large, are in general use there, and central stations, aggregating several thousand horse¬power, are quite numerous. The fact that gas-producer power-plants have received so little attention in America may be attributed to five conditions:-1', ignorance and prejudice; 2, newness of work; 3, in-

Mar 1, 1905

By B. E. Field

Cobalt is a silvery white metal with a slight bluish cast. It strongly resembles nickel in its appearance and properties, notably its resistance to corrosion, although its alloys with other metals differ decidedly in their properties from those of nickel. The name "cobalt" was derived from the German Kobold, meaning goblin, and this came to be applied to the cobalt minerals which, although they resembled ores, did not readily yield metal when smelted by the primitive processes available in the Middle Ages. Cobalt minerals were used as pigments by potters and glass workers before the Christian era. Cobalt blue glass was found in the tombs of the Egyptians and in the ruins of Troy, and many colors used by the ancient Greeks and Romans contained cobalt. The ancients were entirely unaware that the colors they used were caused by cobalt and the metal itself was not isolated until about the middle of the eighteenth century, by Brandt, although the preparation of cobalt compounds had been carried on in a small way ever since the opening of the silver-cobalt deposits at Schneeberg, Germany, in 1470.

Jan 1, 1935

By Frederic P. Dewey

(New York Meeting, February, 1912.) By the old method of determining platinum in ores and bullion, the silver-alloy first obtained in the regular course of assay is parted in strong sulphuric acid and the residual metal weighed. This is re-alloyed with silver by a second cupellation and parted in nitric acid, the residual metal being again weighed. Any difference shown between the two weighings is assumed to be, and is called; platinum. Sometimes it is so, and if any considerable amount of platinum be present, there will be a decided difference between the two weighings; but a slight difference is no real evidence whatever of the presence of platinum. On the other hand, the second weight may equal or possibly exceed the first, even when traces of platinum are present. Again, other members of the platinum group may go into solution in nitric acid more or less. If present, these would be called platinum and escape detection. The method does not provide any direct tests whatever as to the presence or absence of platinum. It is often indecisive, and sometimes jives erroneous results. It is, therefore, quite unsatisfactory. Being called upon many times to determine platinum in a wide variety of materials, particularly when present in very small amounts, I have realized the disadvantages and defects of this old method. In an article on the solubility of gold in nitric acid, 1 I have briefly outlined a method of gathering a little gold out of a solution containing much silver, which furnishes the basis of

Apr 1, 1912

By H. Rush Spedden, Arvid Thunaes

R. R. Knobler and F. E. Albertson—Following the testwork done by Thunaes and Spedden, a Sullivan deck plant was built for the Colquiri mill. This plant started to operate in April 1945 and continues in successful operation. Since May 1950 the Colquiri mill has operated with a completely revamped flowsheet at a rate of 1000 tons per day. The old Sullivan deck section was retained with this new flowsheet. The "slime plant" in Colquiri consists of one 12-cell Denver No. 18-Sp. Sub-A flotation machine, one 16-ft and one 12-ft hydroseparator, six five-deck Sullivan-frames and six shaking tables for cleaning up the Sullivan deck concentrates, as well as 12 Deister plus three Plat-O tables on which the fine sands, which are not treated on the S-decks, are concentrated. Only —325-mesh fines are treated on the Sullivan decks. The combined hydroseparator overflows are fed to the S-decks. From 1946 to 1949, i.e. with the "old" flowsheet and an average mill feed of 800 tons per day an average of 45 tons per day was treated on four Sullivan rougher frames. The two additional frames were used as cleaners. At times, up to 90 and 120 tons of slimes were treated successfully on this Sullivan deck installation. The average operating data for the S-deck section in Colquiri for the year 1949 were as follows: The tests reported in this paper indicated a tin recovery of 42 pct. The actual plant results for 1949 show a 54 pct tin recovery from the Sullivan decks. The total average quantity of tin produced from the S-deck section in 1949 was 15 tons of tin per month. This corresponds to 3 pct of the total mill recovery. The difference between the 6 pct overall recovery-increase expected after the tests in 1943 and the actual plant results given for 1949 is explained as follows. According to the tests, a total of 170 tons was expected to be routed to the Sullivan decks, but because of certain changes in the flowsheet and mill amplifications,

Jan 1, 1951

By H. Rush Spedden, Arvid Thunaes

R. R. Knobler and F. E. Albertson—Following the testwork done by Thunaes and Spedden, a Sullivan deck plant was built for the Colquiri mill. This plant started to operate in April 1945 and continues in successful operation. Since May 1950 the Colquiri mill has operated with a completely revamped flowsheet at a rate of 1000 tons per day. The old Sullivan deck section was retained with this new flowsheet. The "slime plant" in Colquiri consists of one 12-cell Denver No. 18-Sp. Sub-A flotation machine, one 16-ft and one 12-ft hydroseparator, six five-deck Sullivan-frames and six shaking tables for cleaning up the Sullivan deck concentrates, as well as 12 Deister plus three Plat-O tables on which the fine sands, which are not treated on the S-decks, are concentrated. Only —325-mesh fines are treated on the Sullivan decks. The combined hydroseparator overflows are fed to the S-decks. From 1946 to 1949, i.e. with the "old" flowsheet and an average mill feed of 800 tons per day an average of 45 tons per day was treated on four Sullivan rougher frames. The two additional frames were used as cleaners. At times, up to 90 and 120 tons of slimes were treated successfully on this Sullivan deck installation. The average operating data for the S-deck section in Colquiri for the year 1949 were as follows: The tests reported in this paper indicated a tin recovery of 42 pct. The actual plant results for 1949 show a 54 pct tin recovery from the Sullivan decks. The total average quantity of tin produced from the S-deck section in 1949 was 15 tons of tin per month. This corresponds to 3 pct of the total mill recovery. The difference between the 6 pct overall recovery-increase expected after the tests in 1943 and the actual plant results given for 1949 is explained as follows. According to the tests, a total of 170 tons was expected to be routed to the Sullivan decks, but because of certain changes in the flowsheet and mill amplifications,

Jan 1, 1951

By Herbert J. French

ALLOY steels have become essential to industry in meeting the rigid requirements on materials imposed by our, advanced technology. In comparison with the total ingot capacity of the steel industry, the volume of alloy steels is relatively small although for many years annual alloy-ingot tonnage has, been in seven figures. However, the monetary value of the alloy-steel production is exceedingly high and the benefits derived from the products are relatively great. The trend in total ingot production since 1932 has been generally upward with only two major interruptions. That of the year 1938 was due to a decrease in general business activity whereas that of 1946 resulted largely from work stoppages. Traditionally, the tonnage of alloy-steel ingots produced was in the neighborhood of 5 to

Jan 1, 1948

By D. W. Loucks

There is plenty of evidence to indicate that at least one of man's chief interests in life is to make himself as comfortable as possible. If you doubt this, just watch the fellow next to you for the next half hour trying to find the most comfortable position that a hard chair has to offer. Comfort, however, does not always mean an easy chair. To some, it may mean a wealth of money: to another, freedom from worry. But to most of us, it means first of all a comfortable atmosphere in which to live, and to a great many of us it probably also means freedom from that annoying task of firing the furnace. Today more than ever before, automatic heat is one improvement that is placed high on everyone's list. Perhaps this is because automatic heating is becoming relatively cheaper. Perhaps it is because of a good publicity campaign on the part of the oil and gas men or maybe it is just that we are getting lazier day by day. At any rate, almost every issue of Better Homes and Gardens, House Beautiful, or your other favorite home magazine carries an article extolling the virtues of this or that automatic heating system.

Jan 1, 1949

By S. F. Emmons

Jan 1, 1899

ANNUAL meeting of the Woman's Auxiliary of the American Institute of Mining and Metal-lurgical Engineers convened on Tuesday morn-ing, Feb. 20, the president, Mrs. H. W. Hardinge, presiding. President Hardinge, in opening the meet-ing, said: "I have the honor and great pleasure to welcome you to our seventh annual meeting. It has been a happy year, though I started in fear and trembling. My fear is partly gone and my trembling becomes less as time goes on. Never has a chairman had such splendid cooperation and harmony in her work; no. matter how much was asked nor what the task, I have always received the same answer, `We are with you, of course we can do it.' Often the road has been untried and the way full of snares, but we have all pulled together. Is it any wonder we have had a prosperous year? I cannot thank the governing -board and officers enough for their help." Mrs. Hardinge described her trip through the West last summer, during which she visited many of the local sections of the Auxiliary. She also spoke of the work of the Rossiter Raymond memorial library which has been started as an activity of the Woman's Auxiliary. Mrs. Reynders read the minutes of the last annual meeting, and Mrs. Kemp read the treasurer's report. The latter showed that on Feb. 1, 1922, there was a bank balance of $683.61 and on Feb. 10, 1923, the bal-ance was $947.93. Mrs. Westervelt expressed the sorrow of the Auxiliary for the death -of Mrs. Florence Howe Hall and of Mrs. Levi P. Holbrook.

Jan 4, 1923

By AIME AIME

THE Annual Meeting-numerically the 162d meeting-of the American Institute of Mining and Metallurgical Engineers will be held at the Pennsylvania Hotel, 7th Ave. and 33d St., New York, Feb. 18-22, with the exception of the following events: the Mineral Industry Education Division will meet Sunday afternoon and evening at the Columbia University Men's Faculty Club, 400 West 117th St.; and a meeting of the Section Delegates, the annual business meeting of the Institute, and an executive session of the Board of Directors will be held in that order Tuesday afternoon in the Engineering Societies Building, 29 West 39th St., where the Directors will meet in the evening following their annual dinner to the Section Delegates. The Pennsylvania--one of the Statler group of hotels-was selected as headquarters because it has the physical equipment and facilities-for registration, technical sessions of all sizes, luncheons, social events, etc.-as well as the prominence and location desirable for an Institute annual meeting. (A tip for Tuesday afternoon and evening: You can walk underground from the Pennsylvania to within half a block of the Engineering Societies Building,)

Jan 1, 1945

By AIME AIME

TO THE AMERICAN MINING CONGRESS. AMERICAN INSTITUTE OE MINING ENGINEERS. MINING AND METALLURGICAL SOCIETY OF AMERICA. The committee that makes this report was appointed at the meeting of the American Mining Congress, at Denver, Colo., in. November, 1906. The appointment had in view the drafting. of a law for the regulation of quarrying and metalliferous mining under the police laws of the States, with the hope that the uniform adoption of such a law could tend to reduce the number of accidents in mining. Since its. appointment, the committee has had' under serious and continuous consideration the matter with which it was charged. At the meetings 0f the American Mining Congress in 19o7, 1908 and 1909, it reported progress. At the meeting in 1909 it was authorized to present its report not only to the American Mining Congress, but also to the American Institute of Mining Engineers and the. Mining and Metallurgical Society of America, and to present its report in printed form during the interim between meetings of the American Mining Congress. The committee collected from the officials of the States of the Union copies of their mining laws. With the assistance of the Engineering and Mining Journal copies of the laws 0f Great Britain, the Transvaal, New South Wales, Victoria, Queensland, Western Australia, Tasmania, New aland, and certain European countries were also obtained. These laws were subjected to careful study. The first publication of the committee was a summary of the more important metalliferous mining laws 0f this country. Upon the basis of the existing laws of the States of the Union, Great Britain, and the English speaking colonies, a tentative draft. was prepared and printed in limited number in 1909, for convenience in securing the advice and criticism of a considerable number 0f persons engaged in the mining industry. In this way valuable suggestions were received. At the request of the chairman of this committee, Mr. Frederick L. Hoffman, statistician of the Prudential Insurance Company, of Newark, N. J., summarized and reviewed the available statistics of fatalities in metalliferous mining in the United States. Mr. Hoffman's report was published in the Engineering and Mining

Jan 10, 1910

By M. M., Fine

In a laboratory study of grinding and classification' of silica sand, a satisfactory means of producing the medium-fine specification sand desired by producers of flint-glass containers was developed. The best procedure consisted of ball-mill grinding and double classification, which gave a properly sized sand containing less iron than the feed.

Jan 1, 1950

By Charles E. Locke

CONTINUED expansion of gold mining in 1935 led to further developments in treatment methods. In base metals and non-metallics progress is also noted, coincident with greater activity. Statistics are not available yet for 1935 but the trend is shown by 1934 when nonferrous ore mined in the United States was 35,840,737 tons, or 45 per cent more than in 1933. The amount concentrated was 27,167,530 tons or 75.80 per cent of the ore mined, and flotation was used in whole or part on over 96 per cent of the ore subjected to concentration. In the crushing field a new model of the Fahrenwald crusher is promised soon. The Symons fine-reduction cone crusher and Traylor secondary crusher continue to gain as intermediate crushers. A new book entitled "Crushers for Stone and Ore" by William T. W. Miller appeared. The Hadsel mill has been improved still further and a number of installations are in satisfactory operation showing economical power consumption and low wear. An attempt in a

Jan 1, 1936

By C. H. Mathewson

MY treatment of the subject of "Metals of the Future" is imaginative rather than statistical or scientific, because reliable information concerning useful concentrations in the form of ore deposits of by far the majority of the elements does not exist and the chemical, physical, and mechanical properties of the unfamiliar metals are recorded only in fragmentary and uncertain form or not at all.

Jan 1, 1944

By F. V. Lenel

This discussion is concerned with the method of manufacturing, the design possibilities, and the properties of pole pieces for direct-current electric . motors and generators made from iron powder. In such applications as pole pieces, the electric and magnetic properties of the material are of major importance, therefore they are discussed somewhat more fully. However, the main advantage in making pole pieces from powders lies in the rapid and inexpensive method of manufacturing these pieces, and in the flexibility of design, rather than in their superior electrical properties. As a matter of fact, pole pieces from iron powder have found their principal field of usefulness in small electric motors for controls and similar applications where the highest possible flux density in a given design is not required. Fig. I shows a number of different designs for pole pieces made from iron powder. The steps involved in fabricating them are: (I) briquetting—with each stroke of the briquetting press a complete . pole piece is produced; (2) sintering, and (3) sizing, which is a one-step coining operation in a hand-operated punch press. Conventionally small pole pieces are made from laminated electrical sheet steel stock by punching out the laminations and riveting them together (Fig. 2). The powder method has the advantage of being rapid and inexpensive; also, it makes possible the molding of pole pieces with a round hub, which are better from a design standpoint, as will be shown later. It is difficult to make such round-hubbed pieces from laminated stock. The pole pieces could, of course, be machined from solid stock, but this method is not widely used. The raw material for making pole pieces from powder is straight iron powder without the addition of any alloying ingredients. However, the grade of powder used is of considerable importance, as will be shown later when the influence of the grade of iron powder upon the magnetic properties is discussed. Pole pieces are briquetted in the same way that other iron-powder machine parts are made. Because the pole pieces are flanged—i.e., they have a hub and a wing section—they are made in presses that apply pressure from both ends. For best mechanical and magnetic properties, the density throughout the piece should be even and also should be constant from piece to piece. For that reason a powder of constant compressibility from batch to batch is needed for briquetting pole pieces. One method of obtaining the required magnetic properties is to sinter the pole pieces at temperatures higher than are used for most iron-powder parts. A temperature of 2400°F. and an atmosphere of hydrogen has been found satisfactory. No automatic furnaces of the roller hearth or mesh-belt type have yet been developed for such high temperatures. A box-type furnace heated with Globar heating ele-

Jan 1, 1945

By Oscar A. Glaeser

INDUSTRIAL relations in the United States Smelting Refining and Mining Company's Western operations covers the field of personnel and labor relations, and the principal aims are to render service to the employes of the Company and to its operating departments. Accident prevention Safety is a primary function. A safety engineer is employed at each operation. The wholehearted support of Company officials, staff, and the working force has been most successful in preventing accidents. Constant vigilance has been combined with a policy of building safety into all operating activities whether these are in the construction of a new facility, the developmnt of a mining system, or the direction of the working force. That this policy has produced results is attested to by the fact that the accident frequency rate at the Company's major mining operations in Utah has been reduced approximately 75 per cent in the ten-year period ending Dec. 31. 1946.

Jan 1, 1948

By E. V. Daveler, Frank L. Antisell

CERTAIN physical and chemical properties of copper are so intimately related that a change in variation of the physical properties indicates a certain chemical change. The standard specifications of copper of the American Society for Testing Materials are based upon physical characteristics with one exception, namely, the copper contents. Certain phenomena of the surface indicate the adaptability of the metal for forging or rolling. The writer believes that it is much simpler to produce shapes that are metallurgically correct than those that are mechanically satisfactory. The appearance of the surface of the copper when cooled is considered as to its "pitch," or the general contour of the surface, and the "set," or the decail appearance of the surface of the shape. The set of the copper is, in a very large measure, directly related to the pitch; and so intimately are these characteristics connected that they are often used as synonymous terms by the refiner when he is speaking of well-refined copper. Oxygen is often spoken of as a medicine for copper, it being used to regulate the pitch.

Jan 1, 1920

By B. M. Larsen

Jan 1, 1948

By B. M. Larsen

Jan 1, 1948

By Richard Paul Seelig

The following review covers published information on pressing of metal powders at room temperature. Only those operations are considered which occur between the time the powder is filled into the cavity and the compact is ejected from the die. Thus, this review does not concern hot pressing, coining or sizing feed or flow problems, commercial presses nor designs. It was also necessary to disregard to a large extent the effect of pressing on subsequent operations and on properties after sintering. 'The pressing operation is considered independently in its function to compact loose metal powder into useful shapes which can subsequently be handled. There are some comments by the writer in connection with a few of the findings quoted in the literature in order to stimulate thought and discussion. The selection of references quoted in the text is in some cases arbitrary although an attempt was made to favor papers containing novel ideas, techniques or results which mag stimulate future research. In order to enable the reader to check further into the subjects mentioned, the original, rather extensive, bibliography is appended even though not all the references are touched on in the printed version of this review. The equipment used by various workers, for example a die design created by Bridgman,22 is very interesting. 'The die insert has a conical external surface. The vertical pressure exerted on the punch transmits itself to the die which in turn is pushed harder into its tapered retainer. Thus, the higher the pressure exerted on the punch, the higher also the pressure exerted inwards on the die inserts. Inasmuch as this pressure counteracts the internal pressure from the compact the two stresses balance each other so that it is possible to obtain tremendous pressures without breaking the die. The die collar was made from an oil hardening tool steel, heat treated to a tensile strength of some 300,000 psi. The die was closed at the bottom by a plug made from special tool steels. Bridgman found that there is no steel which will withstand a com-pressive stress of 700,000 psi without continuous slow flow or immediate fracture. Therefore, the only material suitable for use in the pressing punch was sintered carbide. In view of the ingenious design it was possible to use special tool steel as die material. Jones22 raises the question whether this method of pressing has practical application in powder metallurgy. Although these tremendous pressures cannot readily be utilized without many special precautions, the tapered die and retainer idea is believed to be useful even for lower pressures. Bridgman, himself," alls attention to the fact that the properties

Jan 1, 1947