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By D. C. Jackling

I BESPEAK your indulgence for a brief expression of the views of a patriarch in the field of mineral industry technology relative to young men's problems in that sphere of education and endeavor. Wherever hereafter I employ the terms "technical education," "engineer," "technologist," or similar expressions, these are intended to be understood as relating to the broad field of the sciences and arts applicable to the mineral industries. First, the usefulness of technical education to either the possessor of it or those to whom its services may be made available industrially depends primarily upon the quality of the education and the capabilities of the educated to put his talents to effective and constructive employment in his chosen field of applied science.

Jan 1, 1940

AALL,Christian H.,(M '49), Asat.Research Dir , Phosphate Div Monsanto Chem.Co.,Monaanto, Tenn. AAMOT,Olav Crone, (M '29), Dir of Tech., Chromium Min. & Smelt. Co Ltd Box 6215, Hillyard, Spokane, Wash. AARING, Floyd Daniel, (J '48), Prod. Engr., Canadian Gulf Oil Co., 8035 - 102nd St., Edmonton, Alta., Canada AASE, Glenn D., (J '40), Met Engr Western Research Div. ,Amer. Smelt. & Refin. Co., Selby, Calif ABADIE, Henry G (M '43), Senior Prod Engr., Long Beach Oil Dev Co., 255 S Santa Clara Ave Long Beach 2, Calif. ABBOTT,Clarence E (M '04), Civil Engr., 901 Insurance Bldg., Raleigh, N.C. ABBOTT, John, H., (M '46), Resident Mgr., Hickman, Williams & Co., Rm 2205,230 N Michigan Ave., Chicago 1. I11.

Jan 1, 1952

By A. D. Hughes

C. W. MERRILL*-Mr. Hughes' paper not only is very well presented but is most timely in that it covers a subject of vital interest to the United States. Tin is one of the strategic metals which has not been found here in appreciable quantities. The total United States tin output since the first recorded production over 100 years ago would not supply current consumption for a fortnight. On the consumption side, tin is extremely important in national defense because of its use in tin plate which, in the form of tin cans, makes it possible to feed properly the armies that the United States recruits from its civilian population in emergencies. Moreover, the internal combustion engines so important in powering tanks, planes, and other war machines, require large quantities of tin alloys for bearings and for soldering. These considerations, along with the fact that Malaya, historically, has been the leading source of tin to the United States, make the kind of information that Mr. Hughes has presented so ably, a matter of vital interest.

Jan 1, 1949

By Paul M. Tyler

ROUGHLY one-half the value of mineral products at mines or quarries must be spent for wages. In view of the steady increase in hourly wages that continued for several decades prior to the onslaught of the recent depression, it is perhaps surprising to discover that labor's share of the gross proceeds of the mining and quarrying industries of the United States declined to 46.8 per cent in 1929, compared with 52.2 per cent in 1919 and 53.2 per cent in 1909. The actual percentages vary in different branches of the industry and in different localities but the downward trend is unmistakable. For the period 1909 to 1919 it was quite marked in every industry and from 1919 to 1929 it was apparent in all but six: namely, gold and silver lode mining, placer gold mining, crude gypsum production, marble quarrying, asbestos production, and fluorspar Tninino mining

Jan 1, 1933

By A. Lawley S. Schuster

The tensile behavior of copper foils prepared from rolled bulk material has been studied over the thickness range 2 to 53 , and for a range of pain sizes. For foils of comparable grain size, having the cube texture and tested along (100), yield strength increases with decreasing foil thickness t below -26p, with a corresponding decrease in ductility. Deformation occurs in the form of localized slip clusters distributed throughout the gage section. To the extent that the tensile strength (10 to 18 kg mm-) is unaffected by foil thickness, and that the foils possess fair ductility, the stress-strain behavior resembles that of bulk material rather than that of whiskers or evaporated films of comparable dimensions. The dependence of yield strength o on foil thickness t below -26p is of the form: oy = oo + kt-1/2. Possible explanations for the stress increase are considered based on 1) the dependence of active dislocation source length on foil dimensions, 2) the locking of surface sources, or the blocking of mobile sources at the surface due to surface film. It is now well-established that filamentary whiskers of many materials show exceptionally high strength compared with bulk crystals.'-11 As the diameter of the whiskers decreases to -1, the observed fracture strength approaches, and in certain cases exceeds, the calculated shear stress for the nucleation of slip in a perfect crystal.' In general, the stress-strain curve is entirely elastic, with strains at fracture approaching 1 pct. Similarly, thin films12-24 of evaporated or electrodeposi-ted material have been shown to possess tensile strengths three to seven times that of bulk material, with total strains at fracture -1 to 2 pct. In the present study, attention has been directed to the room-temperature tensile behavior of thin foils of copper over the thickness range 2 to 53, prepared from rolled bulk material. Yield stress, ultimate tensile strength, elongation to fracture, and work-hardening behavior are measured as a function of grain size and foil thickness. Structurally such foils are superior to either evaporated or electrodeposited films, and in the recrystallized condition exhibit considerable ductility. Apart from preliminary work by Sumino and Yamamoto25 on the work-hardening behavior of rolled and recrystallized copper foils, no systematic tensile studies have been carried out on material of this form. EXPERIMENTAL PROCEDURE Tensile specimens were prepared from 99.995 pct purity rolled copper foils of thickness 2, 6, 12, 26, and 53, obtained from the Hamilton Watch Co., Lancaster, Pa. Irrespective of specimen shape, it is necessary to use tensile foils with edges free from notches or tears. To this end, any form of cutting operation was excluded, and the tensile foils prepared using a photoengraving process, the details of which are described elsewhere.26 Since tensile data are required under conditions of uni-axial stress, the specimen shape is extremely important. Ideally, the foil should be infinitely long, allowing a gradual taper from the grip area to the gage section; however, from a practical standpoint, long foils are easily damaged during testing. A modified tensile specimen was therefore selected having a parallel gage section 1.25 by 0.20 in. with a tapered shoulder section increasing to 0.5 in. at the grips, and an over-all length between grips of 4 in., Fig. 1. In practically all tests, these foils fractured within the parallel gage section. By approximating the foil contour (Fig. 1) to a hyperbola it is possible to analyze the stress distribution in the tensile foil using two-dimensional elasticity

Jan 1, 1964

By A. L. Sweetser

EXPERIENCE has shown how difficult it is to obtain information regarding laboratory-tests in connection with the chlorination-process for the extraction of gold from its ores, and I therefore present the following method, somewhat in detail, for the benefit of those who may desire to pursue research work in this field. The ore chosen was a partly-decomposed porphyry, extremely siliceous and comparatively soft, and of an average value per ton of from $25 to $26 in gold and $0.68 in silver. The chemical analysis gave : Fe2O3, 3.35; FeS, 1.5; MnO2, 0.75; ZnCO3, 4; Al2O3, 3.20; H2O, 0.7; SiO2 and insol., 83.50 per cent. The ore, first crushed to pass a 5-mesh screen, was coned and quartered until a 45-lb. sample was obtained. Samples for assay and analysis, taken from this lot by means of riffles, were crushed to pass a 100-mesh screen. The original sample was divided into 10-lb. lots, of which one was crushed to pass a 10-mesh screen; another through a 12-; the third through a 20-, .and the last through a 30-mesh screen. Because of the production of an excessive quantity of fine material it was deemed inexpedient to crush finer than 30-mesh size-a decision the wisdom of which is proved by the data in Table I., showing the increasing ratio of slimes, in proportion as the ore is crushed finer. In order to determine the percentage of fines in the sizes of mesh selected, a weighed sample of ore was taken from each mesh, and a sample from the 10-mesh lot was passed successively through 20-, 40- and 100-mesh screens, and the percentage remaining on each screen determined. This process was repeated with the 12-, 20- and 30-mesh lots, with the results given in Table I.

Sep 1, 1907

By AIME AIME

MOST recently elected to the limited group of Honorary Members in the A.I.M.E. is the distinguished Australian metallurgist, Guillaume Daniel Delprat. His citation reads: "in recognition of his distinguished achievement as metallurgist, engineer, and administrator in the production of ferrous and nonferrous metals," Mr. Delprat's ability and experience in both the ferrous and nonferrous fields at once distinguishes him from most of his professional brothers. Mr. Delprat's nativity was neither Australian nor English, for he was born in Delft, Holland, in 1856, and educated in Amsterdam. At the age of 22 he went to Spain, as metallurgist for the Tharsis Sulphur and Copper Co., Ltd. Afterwards he spent some time with the Bede Metal and Chemical Co., which had mines in both Spain and Norway, and of which company he became general manager. Other positions of responsibility held by Mr. Delprat before he went to Australia included the managing directorship of the Cordova Exploration Co., with properties in Spain and Canada; of the Rincon Silver-Lead Mining Co., in Spain; and of the Deloro Gold Mines, in Canada.

Jan 1, 1936

By E. J. Duggan

CLIMAX ore is an altered and highly silicified granite, about half of the gangue being quartz. Molybdenite is the only mineral recovered and most of it is intimately associated with the quartz in fine veinlets. Other minerals are molybdite, pyrite, and chalcopyrite. Although the molybdite may be readily extracted by hydrometallurgical methods, its content is too low to make this profitable. The pyrite ranges from 2 to 5 per cent and the chalcopyrite from 0.03 to 0.05 per cent. There is not enough copper to make its recovery attractive and one of the problems is its elimination, and that of pyrite iron, from the final product. On account of the high degree of dissemination of the molybdenite and the necessity of eliminating the iron and copper, fine-grinding followed by flotation is the only known feasible method of concentration. Two factors, peculiar to Climax ore, have a predominating influence on the metallurgical attack: (1) Molybdenite is one of the most easily floated minerals. High recoveries may be made with pine oil alone if the

Jan 1, 1946

[RALPH ADAIR Ore Dressing Consultant Bull Mtn. Rd., Asheville, N. C. Phone 4-1693 JAMES A. BARR Consulting Engineer Mt. Pleasant, Tennessee Washington, D.C. BEHRE DOLBEAR & COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4, N. Y. I. B. BERENT Engineering Consultants and Contractors Mineral Exploration, Mine Evaluation, Mine Designs and Mine Management 158, Ataturk Bulvari-Ankara, Turkey BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 8 Howard-Canfleld Bldg. Santa Barbara, Calif. COWIN & CO. Mining Engineers and Contractors Consulting Shaft & Slope Sinking Appraisal Mine Development Reports Mine Plant Construction 1-18th St. S. W. B'ham, Ala., Phone 56-5566]

Jan 1, 1952

By Nathan C. Rockwood

WHILE mining engineers have been searching in far corners of the country and of the world for hidden wealth there has grown up around us in nearly every city great wealth-producing mines calling for the investment of hundreds of millions of dollars and yielding products now sold for over half a billion dollars yearly-largely unknown and almost wholly neglected by mining engineers. But this neglect is explainable and excusable. They are industries of very recent origin-practically the growth of the last 25 years. They are in a very large measure the result of tremendous developments in engineering construction and the rapidly expanding use of portland cement concrete for structures of every description. Concrete as a material of construction is going through an evolution very much as did cast iron and other metals used in engineering; and this phase of the industry should appeal to the imagination of metallurgical engineers. At first iron was iron-a material of uncertain properties, owing both to small differences in chemical composition and in methods of manufacture. By successive steps iron was studied and knowledge of its properties developed-the striking effects of very small percentages of other minerals and of various heat-treatments.

Jan 1, 1924

Organization Place Date 1919 American Electrochemical Society New York, N. Y. Apr. 3-5 American Chemical Society Buffalo, N. Y. Apr. 8-11 National Foreign Trade Council : Chicago, Ill. Apr. 24-26 American Iron and Steel Institute New York, N. Y: May American Institute of Electrical Engineers Lake Placid, N. Y. June 23-27 American Society for Testing Materials..: Atlantic City, N. J. June 24-27 American Railway Bridge and Building Association Cleveland, O. Oct. 21-23

Jan 4, 1919

||Abad, Leopoldo F., Min Engr, Div of Mines, Bureau of Science Manila, P I '23 Abadilla, Quirico A, Geol, Lago Pet Corp Box 172, Maracaibo, Venezuela '20 ||Abbey, Robert Graham, The W W Sly Mfg Co Train Ave, Cleveland, Ohio '21 Abbott, A. N., Mines Supt, Mazapil Copper Co, Ltd Concepcion del Oro, Mexico '23 Abbott, Clarence E., Mgr, Mines & Quarries, Tenn Coal, Iron & R R Co, 1242 Brown Marx Bldg, Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr , Consolidation Coal Co , Elkhorn Div Jenkins, Ky. '16 Abbott, Robert R., Met Engr , Peerless Motor Car Co Cleveland, Ohio '12 ||Abbott, Wells Osborn, Ray Consolidated Copper Co Hayden, Ariz. '23 Abeel, George H, Jr., Cons Min Engr 4612 West 17th St , Los Angeles, Cal '18 Abel, Albert E., Asst to Pres, Valley Mould & Iron Corp Sharpsville, Pa. '19 Abernathy, George Elmer, Prof of Geol & Min , Kansas State Teachers College, Pittsburg, Kans. '20 Abey, Hiroshi, Min & Met Engr, Min & Met Dept, The Higher Technical School, Osaka, Japan. '17 ||d'Ablaing, Philip R, Chem , Anaconda Copper Min Co Great Falls, Mont '25 Aborn, Robert H , Research Assoc., Mass Inst of Tech Cambridge, Mass '19 Abouchar, Sylvain Sley, Min. Engi & Geol , care of S H Sekaly, 13 Rue El Nimr, Cairo, Egypt '17

Jan 1, 1923

By N. H. Emmons

In the United States the value of gold- and silver-ores is everywhere reckoned in ounces troy of the metal per " short ton " (2000 lbs. avoird.) of the ore. In the case of silver, which fluctuates in market value, the New York quotation on a given day must be known, in order to determine the gross value of an ore at that date. In Mexico the assay is reported 'in kilogrammes of silver or grammes of gold per metric ton. As everyone is aware, this is practically a percentage system, 1 kg. of silver per metric toll (1000 kg.) being 0.1 per cent., and 1 gramme of gold per metric ton, 0.0001 per cent. The notation is simple and convenient for both assayer and miner.* The Mexican government purchases at an unvarying price for silver, payable in silver, and at a fixed price for gold, payable in gold if the seller insists, but preferably in silver at about the rate of exchange between U. S. gold coin and Mesican silver coin. The value of silver is $40.915 per kilogramme in Mexican silver dollars. That of gold is $675.416 per kilogramme in gold coin. The mints do not, as a rule, issue gold dollars, as the government keeps them to pay the interest on the national debt. Almost all bullion containing a considerable percentage of gold is shipped to foreign countries (principally the United States) to be refined. The Mexican mint receives for refining and coining no bullion which is not at least .950 fine in gold and silver, separately or

Jan 1, 1902

By AIME AIME

THE 123d meeting of the Institute was held in New York Feb. 14 to 17, 1921. The total registration was 1199, as compared with 1138 at the New York meeting in 1920. The weather was a strange and welcome contrast to that of last year, when New York was buried under six feet of snow as the result of the fiercest blizzard in its history. This year there was no snow, and the weather was said to be much more like an Arizona winter than New York. A complete program of the Technical Sessions is on p. 9. The discussions of the papers presented will be published in pamphlet form as soon as possible and will be noted in MINING AND METALLURGY in the usual way.

Jan 1, 1921

E. E. Russell Tratman, New York City (communication to the Secretary): Mr. Glenn's paper brings up again the question of the part played by coal-dust in colliery-explosions. In the discussion of Sir Frederick Abel's paper on " Accidents in Mines," read before the Institution of Civil Engineers,? much was said about the dangerous properties of coal-dust, and several instances were given of the successful use of a spray of water, water and compressed air, or exhaust-steam from an engine, to keep the mine SUEciently damp to prevent the formation of dust clouds. Methods of preventing shots from blowing out; of using water cartridges to prevent flame ; and of using lime cartridges, wedges and other means of breaking down the coal were also discussed. Mr. Emerson Bainbridge referred to the explosive termed " roburite " (ammonium nitrate and

Jan 1, 1895

By Paul W. Zimmer, Carl E. Dutton

Iron ore in the Menominee district is mined from two iron-formations of middle Precambrian age. The older formation is present in the northeastern part; is composed mainly of hematite, magnetite, quartz, and minor silicates; and contains about 34 per cent iron. The rock has been so coarsened by meta- morphism that concentration of magnetite and hematite is feasib!e, and pellets containing more than 60 per cent iron are being produced. The older formation is also present in the southeastern part where it has 1:een only slightly metamorphosed. Ore containing more than 50 per cent iron was formerly mined from local residual concentrations of iron oxides from which silica had been sufficiently leached, or replaced by iron oxide, or affected by combinations of these processes. The younger iron-formation occurs in the western part of the district and, if unaltered, is interlayered siderite and chert. The ore in this area also contains more than 50 per cent iron and formed as local residual concentrations but in two stages. The siderite was converted to iron oxides (hematite and "limonite"), and silica was contemporaneously or subsequently removed by leaching, or replacement, or combinations of these processes.

Jan 1, 1968

By Persifor Frazer

CONTENTS. PAGE 1. Committee House of Commons Report (1843).......521 2. Clark (1880).............521 3. Schröder and Schertel (1884).... . 521 4. Committee House of Lords Report (1887).......523 5. Vita (1890).............524 6. Irvine (1890-1)............524 i. Cramer (1891)............525 8. Bailey. Cohen. Tatham and Hartog (1891))......525 9. Morrison (1891)............525 10. Brunner (1891)............525 11. Bell (1892).............585 12. Oades (1892).............526 12a. Purcell (1892)............526 13. Sennett (1892)............526 14. Bulier (1892).............526 1.7. Wiesner (1892))...........526 16. Thomson (1892)............530 17. Fletcher (1892)............530 18. Committee Engineers' Club Report (1892).......530 19. Cohen and Hefford (1892)..........531 20. Discussion Soc. Chem. Ind. (1893). ..532 21. Reuss (1893).............532 22. Thomson (1894—5) ...........535 23. Clowes and Feilmann (1895). ...536 24. Callan (1895)...........536 2.5. Wright (1895)............536 25A. Mabery (1895)............536 26. Re- (1896). ..........536 27. Herman (1896)............ 537 28. Cohen and Russell (1896).......... 537 29. Dennstedt and A hrens (1896). ..537 30. Cohen (1897). ...........537 31. Drehschmidt (1897)........... 538 32. Pfeiffer (1898). .........538 33. Fritzche (1898)............ 540 34. Ost and Wehmer (1899)........... 540 35. Donkin (1899). .........541 36. Beilby (1899)............. 643 37. Berthelot (1900)............ 544

Jan 1, 1908

R. F. MCELVENNY.- Over 20 years ago I went back East on a little tour of copper companies to see how copper was handled and fabricated, and I met a Mr. Bassett who took me through the Waterbury branche of the American Brass Co. I have not seen this gentleman for 20 years, but I have a letter from him that I would like to read to you. 'The American Brass Co. Waterbury, Conn. May 19, 1930. To the-Salt Lake City Conference on Reverberatory Smelting Practice: Through the courtesy of Mr. Scott Turner, Director of the U. S. Bureau of Mines, Mr. G. L. Oldright has been temporarily released from his regular duties to act as your secretary. We have asked him and Mr. McElvenny to make the necessary preliminary arrangements and to present to you at the opening session the greetings of the officers and' directors of the Institute. I am very glad that it has been possible for you to come together under the auspices of the Institute and that the acceptance of our invitation has been so very unanimous. Such an acceptance of the invitation to this meeting indicates your interest in getting together for an exchange of technical data and ideas. We anticipate that this meeting will be of real service to the smelting industry through your open discussion and exchange of ideas, and we sincerely hope that you will form an organization which will arrange for future meetings of a similar nature. While it probably may not be desirable to. distribute the minutes of this conference except to the members who take part in it, we hope that later the Institute publications may be enriched by such matter as you think it desirable to have published; and also, that some of you may be able to offer technical papers for the Institute publications. I hope that you will find a permanent organization desirable and trust that it will be possible for you to form such an organization so that conferences may be regularly called. We hope that you can make use of the Institute organization and that we can be of real service to your industry. With best wishes for your success in this undertaking, I am Most cordially yours, W. H. Bassett, President.

Jan 1, 1930

By H. C. Meister

THE zinc-smelting industry of the United States has grown very rapidly in recent years and bids fair to outrival that of all other countries in the future. On account of the geographical situation of the chief ore-supplies, the industry may be divided into two main groups, the eastern and the western. The eastern and older group includes the works of Pennsylvania, New Jersey and Virginia, which practically control their own ore-supply. The western group includes the works of Illinois, Missouri, Kansas, Wisconsin and Indiana, which do not control their own ore-supply, but are compelled to buy the ore in the open market. It is for this reason that the western zinc-smelting industry has been undergoing continual changes since its inception 40 years ago. During the early discoveries of lead- and zinc-ore in the lead- and zinc-districts of Wisconsin and northern Illinois, the zinc-ore (sinithsonite or " bone " as the miner calls it) had no value and was considered waste; but later, when this ore was found in large quantities, it attracted the attention of metallurgists, which finally resulted, during the early sixties, in the building of the Matthiessen & Hegeler Zinc Works at LaSalle, Ill., the pioneer zinc-works of the West. A few years later, zinc-ore was discovered associated with the lead-ore in Jefferson county, southeastern Missouri, which started the industry at Carondelet or South St. Louis. Still later, the discoveries of zinc-ore in the lead-ore region, first' at Granby and then around Joplin, lead to the introduction of the industry in the southwest Missouri and Kansas districts. At first the development of the industry was slow, but it progressed steadily and it is now one of the leading metallurgical industries of the middle West.

Jan 1, 1905

By GEO M. FOWLER

AN appraisal of the activities of the mining geologists during 1936 clearly indicates the ever in- creasing utilization of geology in the search for ore. Few men with geo- logic training are idle at present; this is particularly true regarding recent graduates. Many have accepted employment in distant fields, such as the Philippines and South America, and greatly increased mineral production from these places reflects their activities. In North America, regions of intense mineralization formerly important are being restudied in greater de- tail and with better understanding; as a result, new mineral wealth is being found in many such districts. Much is being done by private companies and individuals, and it is to be hoped that mining companies will increasingly make available the purely scientific results of such studies by permitting their geologists to publish. On such generosity to a large extent will future advances in ore finding depend.

Jan 1, 1937