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By E. Gilpin

Any estimate of the economic mineral value of an unvisited district is to the mining engineer largely a comparative one. If he knows that certain minerals characterize any given geological horizon he naturally draws upon his experience of the same ores as met by him cinder similar geological conditions. And if he has not had the personal experience, the investigation of the geology of a similar district as given in a trustworthy report enables him to lay a fair basis for conclusions. In a general way these conclusions are of value, and while they pronounce on the possible mineral fecundity of a given district, they

Jan 1, 1890

By Douglas Ragland

Two subjects certain to incite interest among a few practicing engineers and almost all engineering educators are professional recognition and decline in engineering enrollments. It is not surprising that this interest on the part of the educators is universal; it is only regrettable that such an interest on the part of the practitioners is not more widespread. In fact, it is probably the hope of the profession that some of the more penetrating searches now being made into the nature of engineering will generate sufficient cause for perplexity that members of the profession will assume a significant degree of personal concern toward purely professional matters.

Jan 1, 1963

By Richard Miller

The investigations of large-grained specimens carried out by Polanyi and Schmid,1 Sykes,2 Goucher,3 Yamaguchi,4 Gough, Cox, and Sopwith,5 Carpenter and Elam,6 Aston,7 and others have shown qualitatively that grain boundaries restrain the deformation of adjacent crystals. But whether or not the influence of the grain boundary is confined to the glide planes intersected by the boundary has not been demonstrated in any of these investigations, nor has there been carried out any quanti-tative analysis, of the influence of a boundary on the deformation of a crystal. Indeed, the specimens employed in the previous work con-

Jan 1, 1934

By Waldemar Lindgren

THE purpose of this paper is to present certain facts relating to Cordilleran differentiation and metallization. Theoretical discussions concerning the exact modus operandi of differentiation, the causes that led up to it, and the original distribution of the magmas have been omitted because the author feels that his knowledge is deficient. These subjects have been adequately treated in the admirable works of Iddings, Daly, Harker, Tyrrell, Shand, and Wolff. The facts here set forth seem to indicate that differentiation and metallization form one continuous process during the eastward movement of the magmas, culminating in the alkaline province of the eastern border of the Cordilleran Ranges.

Jan 1, 1933

By Thomas F. Donnelly

The Province of San Cristobal is situated on the south side of the island of Santo Domingo about 25 miles west of Santo Domingo city, the capital of the republic. The copper mineraliza,tion is found about 8 miles north of the town of San Cristobal,. in the section known as Bucaro Hill; in San Francisco Hill; on the Nigua River; and on the Jaina River. The district is reached by automobile from Santo Domingo city over an excellent road for 25 miles to San Cristobal, and then, by horseback 6 or 8 miles up the Nigua River to what is locally known as "Camp

Jan 1, 1916

By A. E. Hunt

A GREAT deal that has been written heretofore about the properties of aluminum is of doubtful value, owing to the lack of knowledge we have of the purity of the aluminum referred to. Much of the metal heretofore sold in the markets as pure aluminum has been contaminated with from 4 to 10 per cent. of impurities. Indeed, it is only within a very few years that a purer metal than 96 per cent. alumium has been made upon any larger than a laboratory scale. The works of M. Pechinet,of the Societe Anonyme d' Aluminium, at Salindres (Gard), near Marseilles, in France, have long enjoyed the

Jan 1, 1890

By L. A. Wright, H. L. McKinley

PINE Creek mine of Union Carbide Nuclear Co. is some 23 miles northwest of Bishop, Calif., in the Sierra Nevada Mts. Office and mill are 7800 ft above sea level, the 1500 level portal is at 9300 ft, the A level portal at 10,800 ft, and the 3050 portal at 11,500 ft. Original claims were located in 1916, and the mine worked intermittently until 1936, when it was purchased by Union Carbide Corp. Since then the property has been operated continuously, except for two brief periods when operations were suspended because of manpower shortages. Mine production through 1956 amounted to 2,792,425 dry tons of ore.

Jan 10, 1957

By Herbert Clark Hoover, Lou Henry Hoover

QUESTIONS of assaying were explained in the last Book, and I have now come to a greater task, that is, to the description of how we extract the metals. First of all I will explain the method of preparing the ore1 ; for since Nature usually creates metals in an impure state, mixed with earth, stones, and solidified juices, it is necessary to separate most of these impurities from the ores as far as can be, before they are smelted, and therefore I will now describe the methods by which the ores are sorted, broken with hammers, burnt, crushed with stamps, ground into powder, sifted, washed, roasted, and calcineda.

Jan 1, 1950

The curve of Fig. 3 for pyrite requires modification. There 11% a range of pH values from 6.2 to 7.8 for which no cyanide is required to prevent contact. From 7.8 to 11.3 a small amount of cyanide is required, with a sharp maximum of 20 mg. per liter at pH=9.6. The mistake arose from considering too few solution compositions (17 were considered) in constructing the curve. Subsequent work with other collectors indicates that the corrected curve is typical for such systems; it illustrates the further development of the dip in the pyrite curve of Fig. 5.

Jan 1, 1938

By Gordon Fletcher

Pacific Rim countries currently have plans to import about 100 Mt/a (110 million tpy) of steam coal by 1990. Due to its close proximity, Powder River Basin coals offer a long term economic and dependable source of supply to the Pacific Rim. In existing boilers, Powder River Basin coals can be blended with Australian, South African, or Canadian coals. For new units, Powder River Basin coals are very competitive on a total evaluated cost basis. The advantages of using Powder River Basin coal include: assurity of supply, consistent coal quality, stable labor force, and attractive mining economics. (NOTE: PAPER NOT RECEIVED IN TIME FOR PUBLICATION.)

Jan 1, 1982

It was customary formerly to publish an index of the Transactions about every fifth volume, but since the Institute began in 1913 to publish three volumes instead of one volume per year, this has been deemed impracticable and unnecessary. No collective index has been published since the one covering Volumes I to XXXV inclusive, excepting a short one covering Volumes XXXVI to XL inclusive. The Board of Directors, therefore, upon the recommendation of the Committee on Papers and Publications, decided to publish this index of Volumes XXXVI to LV inclusive, and thus enable members to have in condensed space the collective indexes of all the volumes of the Transactions.

Jan 1, 1918

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) The governing body of the Imperial College of Technology, London, S. W. (Royal School of Mines), will shortly proceed to the appointment of a Professor of Metallurgy. This important Chair has been filled in the past by such eminent metallurgists as John Percy, Sir William C. Roberts-Austen, and others. Inquiry has been received at the office of the Institute for an engineer to examine a mica, deposit in one of the New England States. The position of converter blower at. a side-blow Bessemer steel casting plant is vacant.

Jan 4, 1913

Announcement is made that applications fir the Emmons Memorial Fellowship in Economic. Geology will be considered, and an incumbent appointed prior to the first of June. Applications should be sent to Professor J. F. Kemp of Columbia University not Intel: than May 15. . The holder of this fellowship receives an income of $1,000 and is expected to carry on an investigation in Economic Geology which will add a distinct contribution to the literature. The institution at which the study is pursued will be decided after conference with the members of the Committee of Awards. The character of the investigation will be decided after applications have been passed upon.

Jan 5, 1917

The Committee appointed by your Board of Directors to nominate Officers for the Institute for the year 1915 invites the participation of all members in the nominations. The suggestion of names for the various offices will be appreciated and given full consideration when making the selection of candidates which this Committee will recommend. The officers to be elected at the annual meeting in February, 1915, are: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and VII of the Constitution, and to By-Law XIII, which reads as follows:

Jan 6, 1914

By W. R. Toeplitz

H. N. Ghenn.*—It has been established that the accuracy obtainable from any precision machine is a function of the wear resistance, maintenance and closeness of fit of the bearings, hence I would like to ask Mr. Toeplitz how these oil-less bearings compare with cast iron or babbitt or similar materials when used on precision machinery. Could these bearings be used, for example, on a grinding machine in which work must be held to a tolerance of plus or minus 0.000025 inch? W. R. TOEPLITZ.—The metal-powder bearings can be held to very close tolerances and are used in place of cast iron and babbitt on precision machinery.

Jan 1, 1945

THE papers presented by the Institute of Metals at the Detroit meeting in September, 1926, and the New York meeting, February, 1927, will be issued soon in one volume and mailed to all members of the Institute of Metals Divi-sion of this Institute. The, annual lecture given by Cecil H. Desch will begin the volume and the discussion occurring at the sessions, as well as subsequent written discussions, will be appended to each paper. The volume will contain about 600 pages, and will be sent without charge on request to any member of the Institute. The pre-subscription price to non-members is $5.

Jan 4, 1927

By John V. Beall

IKE'S amiable expression and apparent sincerity impressed AIME members as did the theme of his talk. Cautioning against the gradually increasing power of the federal government, he said: . . . "freedom as we know it is in no greater danger from without than it is from our own lack of understanding of this creeping paralysis from within." Next February, it will be three years since he uttered these words at Annual Meeting welcoming ceremonies, but the theme was oft repeated in his winning campaign. This brush with the exalted, brief though it was, makes Washington look friendlier to many AIME members than it has for years.

Jan 1, 1953

STANFORD UNIVERSITY, CALIFORNIA Our activities for the year 1918-19 have closed with the coming of summer. It has been a most successful year in many respects, especially in the reorganization necessary after the war conditions had passed. An INITIATION SCENE AT STANFORD UNIVERSITY. "old-days" initiation was held on the Stanford campus by the Society a few weeks ago. The accompanying picture explains some of what took place when the following men were taken into the membership: W. P. Winham, Salinas, Calif. ; T. L. Wark, Long Beach, Calif.; P. L. Henderson, Greeley, Colo.; T. E. Bassett, Palo Alto, Calif.; and R. G. Wheelton, Long Beach, Calif. CHAS. A. DOBBEL, Secretary.

Jan 8, 1919

SIR ROBERT HADFIELD, London, England (written discussion*).-We have in the past known so little about tungsten that an important paper such as Mr. Zay Jeffries contributes is most welcome. I have not much personal knowledge on the subject except as regards combinations of iron with tungsten. I put forward the results of my research on natural alloys in 1903,1 and so far as I know the facts there presented still stand. Singular to say, tungsten added to iron affects the electrical resistance less than any other added element. The following tables taken from research work by myself and Sir William Barrett may be of interest.

Jan 10, 1918

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the first half of March: James C. H. Ferguson, San Francisco, Cal. Capt. A. F. Lucas, Washington, D.C. Henry Adams, Stamford, Conn. Dexter P. Cooper, New York, N. Y. H. A. Wheeler, St. Louis, Mo. L. D. Moore, Chatham, N. J. John M. Sherrerd, Easton, Pa. Hennen Jennings, Washington, D. C. R. T. White, formerly General Manager of the Braden Copper Co., Chile, is to take charge of a copper company in Caucasus, South Russia.

Jan 4, 1914