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By Harold Margalin, Elmars Ence

M. H. Mueller, M. V. Nevitt, and H. W. Knott (Argonne National Laboratory)—We have reported1 the crystal structure of Ti2CU as body centered tetragonal with a. = 2.944A and co = 10.786A, six atoms per unit cell, and space groupl4/mmm(MoSi2 type). This cell is larger but definitely related to the unit cell reported by the authors. It permits definite positions for the titanium and copper atoms in the cell located as follows: 2 Cu (a) 0 0 0; 1/2 1/2 1/2 4 Ti (e) 0 0 z; 1/2 1/2 1/2 + z; 0 0z; 1/2 1/2 1/2- z where z = 0.341 The face centered tetragonal cell reported by the authors can be transformed to a small body centered tetragonal cell with flo (small bet) = ao(fct)v2 Both unit cells have the same CO. Neither the face centered tetragonal cell with four atoms per unit cell nor the small body centered tetragonal cell with its two atoms per unit cell lend themselves conveniently to an orderly arrangment of the 2 to 1 ratio of titanium to copper atoms. When the co of this small body centered cell is tripled, however, a large body centered tetragonal cell results with six atoms per unit cell as described above. We had also noted that the X-ray patterns of Ti2Cu indicated that the structure could be approximately described by the face centered tetragonal cell as reported by the authors; how- ever, there was evidence for a few additional very weak lines whose positions indicated a larger unit cell. Since the X-ray scattering amplitudes of titanium and copper are nearly equal, it is evident that it is difficult to distinguish their positions especially from X-ray powder patterns. It was therefore decided to look at a powder pattern obtained by neutron diffraction since the scattering amplitudes of the two elements are considerably different in magnitude and opposite in sign. The sample used for neutron diffraction was selected from a group of three alloys prepared by arc melting using crystal bar titanium of 99.92 pet nominal purity and 99.999 pet pure Cu. The alloys designated as A, B, and C had the following respective compositions: Ti-32.8 at. pet Cu, Ti-33.3 at. pet Cu, and Ti-33.8 at. pet Cu. On the basis of the melting losses incurred, it was established that the actual concentration of either component in any of the alloys probably did not deviate from the intended value by as much as 0.1 at. pet. The alloys were annealed for 5 days at 700°C in evacuated Vycor capsules and quenched in tap water. The metallographic structures of these alloys are shown in Fig. 1. None of the alloys contained sufficient second phase to permit its positive identification. Since alloy B contained the least amount of second phase and since its composition placed it closest to the ideal stoichiometry, it was chosen for the neutron diffraction study. The oxygen content of alloy B was found by chemical analysis to be 0.06 at. pet. This particular intermetallic compound is especially suitable for investigation with neutron diffraction since if the titanium and copper atoms have a random statistical distribution, a near null-matrix would result in which there would be practically no coherent scattering of neutrons, and hence no Bragg diffraction peaks. Such a condition could come

Jan 1, 1962

By W. O. Philbrook, K. M. Goldman, G. Derge

EQUILIBRIUM conditions for steelmaking reactions have been studied extensively over the past two decades by a .number of investigators, with gratifying results. Equilibrium data are essential to the understanding of any process, and such knowledge has the practical utility of placing a limit beyond which control measures cannot succeed. When, however, the driving rate of an industrial process is so fast that there is not time for reactions to reach equilibrium, it then becomes necessary that the factors which control the rates of reaction be known in order to establish full control of the process. The desulphurization of molten pig iron by slags within the iron blast furnace is one such process in which the actual degree of sulphur absorption by the slag does not approach the equilibrium distribution obtained for similar slag-metal systems in the laboratory.' A study of the rate-controlling factors governing the desulphurization of iron by slags is becoming increasingly important as the sulphur content of raw materials increases with depletion of higher grade ores and coal. Following up an initial study on kinetics,' this paper reports some results of a continuing laboratory investigation on the mechanism of sulphur transfer between molten iron saturated with carbon and slags of the CaO-SiO,-A12O3 system. Laboratory experiments cannot reproduce in detail the conditions which prevail in the hearth of a blast furnace, but they will contribute to an understanding of the smelting reactions and perhaps will explain some apparent inconsistencies in the factors controlling the equilibrium distribution of sulphur between iron and slags under reducing compared with oxidizing conditions. The mechanism of a reaction—that is, the individual steps and the sequence in which they occur to produce the overall reaction which is ordinarily observed—must be elucidated to learn which steps are the slow ones, or "bottlenecks," that fix the pace of the process as a whole. In the desulphurization reaction, for example, the overall rate might, in principle, depend upon the rate of diffusion of sulphur in the metal or in the slag, upon the speed of some homogeneous reaction taking place entirely within one of the phases, or upon some heterogeneous reaction taking place across the slag-metal interface. Even some side reaction or the back reaction might have some influence. Evidence on all of these points will be presented in this paper. The rate of diffusion of sulphur in both iron and slag is so slow that it seems necessary to assume that convection provides the mechanism of carrying

Jan 1, 1951

THE purpose of this chapter is to present a general outline of the basic open-hearth process for the benefit of students, practicing open-hearth operators, and metallurgists who wish to review the subject. The discussion is limited to a description of the sequence and purpose of the operations, illustrated by data and examples. Subsequent chapters deal with more detailed and fundamental studies of the subject. The function of the basic open-hearth furnace is to convert various types of ferrous material into finished steel of given com- position and quality. In comparison with other steelmaking methods, the basic open-hearth process is one of the most versa- tile, both from the standpoint of the raw materials that can be used and the types of steel that can be produced. The process can be considered as a sequence involving melting, refining, and deoxidation. With some types of liquid-metal charges, the melting stage is not present, but refining and deoxidation in varying degrees are fundamental features of the process. GENERAL DISCUSSION OF BASIC OPEN-HEARTH PROCESS The first consideration in open-hearth practice is the type of charge on which the operation is based. This consists of three components-fluxing, oxidizing, and metallic materials. Fluxes. In the basic process the fluxing material is primarily lime, added in the form of either limestone (CaC03) or burnt lime (CaO) . This is supplemented by magnesia (MgO) and lime from the furnace bottom and banks. The function of these fluxes is to form a slag with the silica (SiO2) , manganese oxide (MnO), iron oxides (FeO and Fe203), and phosphorus oxide (P205) that are produced by the oxidation of varying amounts of the silicon, manganese, iron, and phosphorus in the charge during melting and refining. The slag, composed of the basic fluxes and the neutral and acid oxides, floats on top of the steel bath when the charge is melted. The composition of this slag depends on the amount of each slag-forming element present in the charge and on the extent of oxidation of these elements during the course

Jan 1, 1964

By W. F. Holbrook

THE problem of sulfur control is important in all blast-furnace operations but particularly for certain grades of steel because of the rigorous specifications. During the past decade the tendency has been to produce pig iron, and, hot metal of lower sulfur content. As most of the sulfur in the ion originates in the fuel, the use of high-sulfur coke demands modifications in practice to meet sulfur specifications. While it is generally known that high temperatures and more basic slags favor desulfurization, operators as a rule produce the most acid slag that will permit proper desulfurization. The viscosity of blast-furnace slag has been thought to be related to desulfurization and has been investigated by Feild and Royster1, also McCaffery and his associ-ates2, but apparently no systematic effort has been made to determine the relative desulfurizing powers of slags over the range of composition encountered in practice.

Jan 1, 1936

By T. J. Whalen, M. Humenik

The liquid surface tension of copper-nickel ad copper-nickel-titanium-carbon alloys and the wettability of titanium caybyde by these alloys have been measuhed. It was found that the surface tensions of the binary copper-nickel alloys Lie on a smooth curve between the end members, copper and nickel. The addition of small amounts of titanium and carbon has nO effect on the surface tensions of copper-nickel alloys. Small additions of nickel to copper significantly reduce the contact angle of Ike alloy with titanium carbide. From a Gibbs treatment, nickel is shown to be adsorbed at the titanium carbide-alloy interface. X HE microstructure of two-phase materials has been shown to be influenced largely by the interfacial energies between the phases present.' , In systems prepared by powder metallurgy techniques and densi-fied in the presence of liquid phase, a precise analysis of microstructure and interfacial energy relationships requires a knowledge of the solid-solid interface energies and liquid-solid interface energies. However, marly metal-nonmetal systems are characterized by the "sweating" of the liquid during sintering, and in these systems wettability is a principal consideration. The wetting in turn is dictated by the various interface energies of the system, as shown in Fig. 1 for a liquid drop formed on a solid substrate. The equation which expresses the vectorial balance of surface forces in the horizontal plane, at the point of contact, A, is given by: where ssv = solid-vapor interface energy sSL = solid-liquid interface energy sLV= liquid-vapor interface energy 6 = contact angle measured through the liquid phase. The angle and the surface tension, slv, can be measured accurately by the sessile drop method.3, The absolute value of the surface energy of the solid cannot be determined by this method, but with reasonable changes in the composition of the liquid only, the value of ssv can be considered constant. The changes in contact angle, then, can be attributed to changes in sSL and sLV and since sLV can be measured, the changes in sSL can be determined. Several studies have indicated that the surface and bulk properties of solid alloys can be correlated with electronic structure. The catalytic activity of copper-nickel alloys was reported to follow the dband vacancies in these alloys.5 Nickel has been considered to have 0.6 holes per atom in the d-band. The addition of copper to nickel is thought to bring about a filling of the d-band of nickel, since each copper atom contributes one electron. Thus, at an atomic concentration of 60 Cu-40 Ni (62 wt pct Cu-38 wt pct Ni) the d-band is believed to be full, and magnetic measurements support this view.6 If the electronic structure is influencing a property of the alloy, this property should show some sort of discontinuity as the composition changes from one side of the 60 Cu-40 Ni composition to the other. Since the catalytic activity can be considered as a surface property of the alloy, it is logical to assume that other surface properties, such as surface tension, may also be influenced by electronic structure. The suggestion has been made that there is a correlation between the solid titanium carbide-liquid Cu-Ni alloy interfacial energy and d-band filling.7 One purpose of this investigation was to determine if the changes taking place in the electronic structure with compositional changes in the solid copper-nickel alloys were reflected in the surface tension values of the liquid alloys. Such a change, if present, would lend support to the suggestion that one can refer to discrete energy bands in the liquid state. Other purposes of the present study were to investigate in detail the wettability in the system copper-nickel-titanium carbide, and to discuss the possible processes which take place during wetting in this system.

Jan 1, 1961

By T. N. Andersen, K. J. Richards, C. N. Wright

The kinetics of the important reactions occurring in an electrowinning cell have been determined. This information has been used to quantify relationships between the operating variables of current density, solution composition, agitation, and temperature and the resulting current efficiency and deposit quality. Analysis of these results has shown (1) the importance of dissolved iron in determining maximum possible current efficiency and corrosion rate at the cathode suspension loop, (2) the role of agitation, current density, inert salts and temperature in*determining deposit quality and (3) the effects of non-uniformity in the hydrodynamic conditions from the bottom to top of the cell. The significance of the results of this study to the operation of a commercial plant directly treating acid leach solutions is discussed.

Jan 1, 1973

By Earl S. Greiner, Eric R. Jette

Although the mechanical and chemical characteristics of certain iron-nickel-silicon alloys have been investigated,1 the available literature shows no results of a systematic investigation of the constitution of this system. 'This paper describes the results of an X-ray investigation of the constitution of the iron-rich iron-nickel-silicon alloys at 600°C. Data 011 the constitution of the included binary systems obtained in other investigations have been correlated with the structure of the ternary alloys. Jette and Foote2 have presented a tentative constitutional diagram of the iron-nickel system. following X-ray studies on quenched specimens. This diagram shows that the alloys at 600°C. containing from zero to approximately 4 atomic per cent nickel consist of a body-centered cubic (alpha) phase, the alloys containing 4 to 24 atomic per cent nickel consist of body-centered cubic (alpha) and face-centered cubic (gamma) phases, and the alloys containing from 24 to Ioo atomic per cent nickel consist of a face-centered cubic (gamma) phase. These investigators recognized that it was not possible to retain the gamma phase in equilibrium by quenching alloys containing less than approximately 25 atomic per cent nickel and that high-temperature X-ray methods were desirable to determine the gamma-phase solubility limit. In a later investigation of the iron-nickel alloys, Owen and Sulley3 determined the alpha-phase solid solubility limit to be 3.5 atomic per cent nickel at 600°C. High-temperature X-ray methods showed the solid solubility limit of the gamma phase to be 14 atomic per cent nickel at 600°C. Since the high-temperature X-ray method should reveal equilibrium conditions in these alloys better than the quench method of other investigators, the results of Owen and Sulley pertaining to the gamma-phase boundary are to be preferred. As the result of an X-ray investigation of quenched iron-silicon alloys, Greiner and Jette4 have shown these materials to consist of a body-centered cubic (alpha) phase containing from o to 26.4 atomic per cent silicon at 600°C. The alloys containing from 26.4 to approximately 50 atomic per cent silicon consist of two phases at 600°C.; namely, alpha and eta. The eta phase corresponds to the stoichiometrical formula FeSi (33.4 wt per cent Si)." The literature pertaining to the constitution of the nickel-silicon alloys has been reviewed by Ackerman,' who found disagreements in the results of various investigators on several parts of the system. Subsequent data on the constitution of the nickel-silicon alloys were reported by oSawa and okamoto.6

Jan 1, 1943

By Morris Cohen

STAFF: Editor, Gerhard Derge Acting Editor, Paul G. Shewmon Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: Karl L. Fetters, President; J.S. Smart, Jr., Past-President; R. C. Cole, Vice President; R. L. Hennebach, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: W. O. Phil-brook, Chairman; H. L. Bishop, R. C. Cole, J. N. Hobstetter, W. A. Krivsky, E. R. Morgan, F. C. Langenberg, R. E. Lund, Paul Queneau, L. L. Seigle, R. L. Smith, and T. V. Wainwright. Review and selection of manuscripts is under the supervision of the following Publicotions Committes: Extractive Metallurgy Division: R. E. Lund, Chairman; M. E. Wadsworth, Vice Chairman; D. H. Baker, Jr., G. M. Bell, R. E. Grace, W. A. Krivsky, R. A. Lewis, Charles O'Neill, A. W. Schlechten, R. E. Shinkoskey, and W. W. Stephens. Iran and Steel Division: T. V. Wainright, Choirman; H. L. Bishop, R. E. Boni, T. E. Dancy, D. W. Murphy, Johannes M. Uys, J. B. Wogstoff, and R. G. Ward. Institute of Metals Division: J. N. Hobstetter, Chairman; P. A. Beck, J. J. Becker, G. F. Bolling, J. 0. Brittain, J. B. Clark, R. S. Davis, A. E. Dwight, R. W. Fountain, L. R. Girifolco, J. C. Gurland, H. S. Kalish, E. L. Harmon, J. J. Heger, A. A. Hendrickson, L. Himmel, J. P. Hirth, H. H. Johnson, Jr., R. R. Nosh, T. N. Rhodin, R. H. Richman, H. C. Rogers, W. Rostoker, C. Sherby, C. W. Spencer, L. Slifkin, J. K. Stanley, R. Steinitz, H. C. Stumpf, and R. Swalin. Published bimonthly by the Americon Institute of Mining, Metallurgicol, and Petroleum Engineers, Inc., 345 East 47th Street, New York 17, N. Y. Telephone PLaza 2-6800. Subscription $30 peryear for non-AIME members in United States and North, South, and Centrol America; $32, foreign; $30per$7.50 for AlME members. Single copies, $6.00, single copies foreign, $6.50. The AlME is not responsible for any stotement made or opinion expressed in its publications ... Copyright 1962 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AlME New York . . . Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts . . . Second class postage paid at New York, N. Y., and Ann Arbor, Mich. Volume 224, Number 4.

Jan 1, 1962

By Edward H. Williams

In the middle of the eighteenth century John Frazier and wife, Sarah Ingraham, removed from Boston, Mass., to Philadelphia, Pa., where he was held in such esteem that we find him one of the Committee which arranged the ball at Washington's inauguration. Their son, John Nalbro Frazier, was prosperous in his mercantile career and fortunate in his wife, Anne West, who was an important personage in the early life of Professor Frazier. This cultured lady brought into the family an atmosphere of religious enthusiasm, of thoroughness and of unity of purpose. Her son, Benjamin West Frazier, inherited her traits and displayed them during a short and active life. Like his father, he engaged in mercantile pursuits, and was a member of the firm of Zimmerman, Frazier & Co. In their interests he lived for a short time in Montevideo, and on

Jan 1, 1906

By Cyril Wells, Robert F. Mehl

The two earlier papers in this series1,2 presented data on the rate of diffusion of carbon and of manganese in gamma iron. Apart from their scientific interest, these data are needed chiefly in order to treat data on carburization, on rate of formation of pearlite, and on rate of austenit-izing in a quantitative way.1'2'9'10 In the present investigation rates of diffusion of nickel in ?-Fe over wide temperature and concentration ranges have been determined, and the effects of carbon, of im- purities, and of grain size on these rates have been studied. Claussen,3 using the data of Fry,4 has calculated the diffusion coefficient of nickel in y-Fe as 9.2 X 10-11 sq. cm. per sec. at 1200ºC., but had no data from which to calculate the variation of D with concentration, temperature, and percentage of carbon. Method and Materials Method.—Nickel was diffused along the axis of a cylindrical specimen across a concentration gradient, concentration-penetration curves were determined and D values calculated from Grube or Matano solutions.5 Details of the method are given

Jan 1, 1941

These springs arc situated on the south bank of the river about four miles below the City of Great Falls. In addition to the spring on the bank there are several in the bed of the river. Estimates on the flow of all these vary from 350 to 600 cubic feet per second, and as the temperature is practically constant at 53° F. throughout the year, the effect on the river water is to prevent the formation of anchor ice at the Rainbow Fails power development below, trouble of this source being in evidence every winter at the Black Eagle Falls above. Geologists claim that the water of the Giant Springs is derived from seepage through an old pre-glacial channel of the Missouri River now occupied by Sand Coulee, five miles up-stream from Great Falls. The water in this buried channel seeps through the flat-lying sandstone of the region and again unites with the present stream at the site of the springs.

Jan 1, 1913

By E. van Walsum

Tunneling methods through rock have, since the successful development of explosives, relied almost solely on blasting. Over the last ten years, rock-tunneling machines (moles) have been developed and some major projects have been carried out successfully with the use of such machines, which rely on the destruction of rock by mechanical means rather than blasting. Various other basically new methods are presently under study, such as the use of laser beams, water jets, etc. For practical purposes, there are presently only two methods commercially available: 1) blasting or 2) tunneling by mole. A contractor would choose at present either one method or the other. Both methods have their advantages and disadvantages (Fig. 1). The thought has occurred that the next practical development in rock- tunneling technology might be a combination of the best features of the mole technique and those of the blasting technique. A preliminary evaluation of this approach indicated that there is definitely a good potential for fruitful developments along these lines. My purpose is to place on record some of the thinking and some of the ideas which were developed along these lines and to point out certain areas where development efforts are required. In trying to find an improved tunneling technique, we looked in particular for the following qualities: 1) safety, 2) continuity, 3) uniformity, 4) automation, and 5) flexibility. TUNNELING BY BLASTING Conventional tunneling by means of blasting proceeds generally in recurring sequences of events: 1) drilling, 2) loading, 3) firing, 4) mucking-out, and supplementary operations (such as scaling and lining). These four operations (drilling, loading, firing, mucking) proceed one after another.

Jan 1, 1970

By M. Tsunekawa, T. Takamori, T. Hirajima

In spherical agglomeration in water, the pattern of the growth behaviour of agglomerates is essentially determined by the surface chemical properties of the particles and the oil-water interface. When particles are suitably hydrophobic and oil-water interfacial tension is not too low under an adequate condition for agglomeration, large agglomerates are formed in the initial stage and micro- agglomerates do not appear. When particles are poorly wetted by oil and the interfacial tension is low, initially micro-agglomerates are formed and, after certain aging time, they grow to large agglomerates in a relatively short time without formation of intermediate size agglomerates. Under adequate conditions, the amount of oil and power input do not produce any remarkable effect on the pattern of growth.

Jan 1, 1980

By W. P. Blake

FORGING under the hydraulic press, which was introduced by Haswell in the year 1861, at the machine shops of the Imperial State Railway Company of Austria, has since been greatly improved, so that at the present time there are very few parts of machines which cannot be produced in this way, and at no greater cost than iron castings. The process is now used at Vienna chiefly for such parts of locomotives as cross-heads, link-bars, axle-box frames, etc., especially where the form is intricate, and there are many angles and projections. These objects weigh from 50 to 150 lb. or more, and it is claimed for them that they are not only much cheaper than ordinary forgings, but are much more regular in form and stronger. The results which Mr. Haswell has attained, after years of patient experimenting, were well shown in the Austrian Department of the Vienna Exhibition by a collection of the pressed objects in iron and steel, just as they left the moulds, with some of them cut asunder longitudinally and the surfaces etched, so as to show the internal structure or direction of the grain. Through the courtesy of Mr. Haswell and his son I saw the hydraulic presses in full operation at the works, drawing down large Bessemer ingots, cutting them up into blocks of convenient size, and forming various parts of locomotives. They have two large hydraulic presses in use; the largest, with a piston 24 inches diameter, gives 1200 tons pressure, and the second, with an 18-inch piston, gives 600 tons pressure. The pressure in the pumps is 600 atmospheres. The action is vertical ; the piston descends upon the work, and for forging ingots is armed with a hammer-like head. An ingot of No. 7 soft Bessemer steel, which was forged in my presence, weighed 2030 lbs. One end being placed upon the anvil, the piston is brought slowly down and crowded into the mass as if it were putty or dough, forcing it each way, but chiefly in the direction of the length of the ingot, this being the narrowest section of the anvil and hammer. The piston is then raised and the ingot is moved forward for a second squeeze, and so on, until the first half of the ingot has been reduced in thickness, when it is turned on edge and the operation is repeated. The ingot is then turned end for end and forged until the whole length has been re-

Jan 1, 1874

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York LOUIS D. HUNTOON, Chairman. ARTHUR S. DWIGHT, Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. E. MALTBY SHIPP. Treasurer. GEORGE F. KUNZ, W. DE L. BENEDICT. Boston ROBERT H. RICHARDS, Chairman. ALBERT SAUVEUR, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. TIMOTHY W. SPRAGUE, HENRY A. WENTWORTH. Columbia F. A. THOMSON, Chairman. GEORGE W. RODDEWIG, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. R. S. McCAFFERY. S. H. RICHARDSON.

Jan 3, 1914

By Charles N. Bell

The Telluride mining district of southwestern Colorado is defined by the 37" 45' and 38" parallels of latitude and 107" 45' and 108" meridians of longitude. Telluride was never a boom camp, but has had a steady growth. In recent years, notwithstanding the business depression of 1920, the business has been the same as in normal years. The first prospector is said to have appeared in 1875, in which year locations on the Smuggler vein were made. Shipments were made in 1877 and 1878, and in 1879 milling the ores was attempted. While the district produced high-grade ores, it did not become important until 1890, when the Rio Grande Southern R. R. was completed from Ridgway to Telluride. The railroad has since been extended to Durango. In the fall of 1896, 400 stamps were in operation, and the annual production was $3,000,000.00, two-thirds of which was gold. The total production from 1875 to 1923 was: gold $58,274,527; silver 41,-830,920 oz., valued at $31,016,893; copper 15,258,866 lb., valued at $2,533,291; lead 166,056,484 Ib., valued at $8,324,910; zinc 18,141,182 Ib. valued at $1,323,787; or a total production of $101,473,408. All claims are held in fee. Most of them are 1500 by 300 ft. but claims located within the last few years are 1500 by 600 ft. General supplies are obtained at Telluride, Denver, and Salt Lake. The largest mines are within 6 miles of the town of Telluride. Denver is 422 miles and Salt Lake is 439 miles, by rail, from Telluride. One-half of the distance to Denver and one-sixth of the distance from Telluride to Salt Lake is by narrow-gage railroad. The labor is efficient. The best miners are Italians and Austrians, then Slavs, Greeks, and Mexicans follow in the order mentioned. There are no labor unions. There are no serious mine pumping problems, the drainage being through adits. The Tomboy and Smuggler companies pump water from their reservoirs, the former for milling and domestic purposes and the latter for milling, power, and domestic purposes. BIBLIOGRAPHY A partial bibliography of the Telluride District is: Geologic Atlas Telluride No. 57; Preliminary Report on the Mining Industries of the

Jan 1, 1925

By Francis H. Crockard

During the past five years we have probably witnessed greater technological advances than in any similar period. Industry and science have steadily marched ahead. The makers of iron and steel products have watched with great interest the development of streamlined trains, faster and safer airplanes, the entirely new science of air-conditioning and the widespread use of stainless steels. Since 1930, we have witnessed the erection of the world's largest suspension bridge, the largest and fastest ocean liner and the spectacular Boulder Dam, while even greater things are planned in these particular fields. Other industries, too, have been moving ahead rapidly. This advance in a few years has been caused primarily by the fierce competition of the depression. Now, more than ever, is the emphasis placed upon quality and service. Makers of southern merchant pig iron have been no exception and have been confronted with increasingly strict chemical specifications and with much greater stress on physical characteristics than ever before. For example, sulfur in the iron must be held very low, competition demanding that it be in the 0.020's and low 0.030's; silicon content must be held within a very narrow range, and definite requirements of phosphorus and manganese are an essential part of the specifications. Physical characteristics are becoming of increasingly greater importance. The introduction of triple-skimmed, slow-cooled iron several years ago was the first step in this direction. Now there are a few customers who buy iron by chemical analysis and physical appearance, having found that the analysis alone is an insufficient guide to their requirements. In addition to questions of quality, the subject of cost has greatly altered the southern furnaceman's viewpoint on many things. Formerly we had low-grade but cheap raw materials, but recent developments, such as greatly increased labor rates, have raised the cost of the same

Jan 1, 1936

By E. J. Roberts

Hydrometallurgical operations and many processes in the chemical industry require the separation of dissolved material from solids. One of the decisions which has to be made in designing a plant for such an operation is how this separation shall be accomplished. It is the purpose of this paper to set forth the general principles involved in such separations in order that the optimum flowsheet and equipment may be selected. Countercurrent Decantation with thickeners, or C.C.D. as it is generally known, is, of course, only one way of separating dissolved material from undis-solved. Other unit operations such as Countercurrent Filtration (C.C.F.) and Countercurrent Classification (C.C.C.) are widely used. The same principles may also be applied to centrifugally assisted decantation, as with nozzle or solid bowl type centrifugals, and to separations using screens, either gravity or centrifugal type. Another form of countercurrent washing applicable to granular materials is practiced in continuous ion exchange operations. All of these operations depend on two basic principles, or combinations of these principles. In C.C.D. type operations the solids are concentrated into the smallest possible volume of liquor in each step and the resulting pulp then mixed with a more dilute liquor and recon cen trated, the liquors separated from the more dilute stages being advanced to dilute the more concentrated liquor in a previous solids concentrate, as is shown in Fig. I. This will be termed the solids concentration-solution dilution principle, or, for short, solution dilution. countercurrent decantation- type circuits. The second principle used in washing solubles from solids is that of solids concentration-solution displacement. Here the solids are restrained from movement while wash solution is forced through the interstices in a counter-current fashion, as in Fig. 2. In the simplest application of this principle, once the "cake" has been formed, it is not disturbed until the operation is completed. In continuous filters, the cake is merely moved under the successive washes and the displaced filtrates removed as in Fig. 4. Often, however, after one or two displacement washes, a repulping step is introduced, the cake reformed and washed again. This procedure brings the solution dilution principle into play as well as the solution displacement principle. Merely thickening ahead of filtration, which is often operationally advantageous, does not hybridize he circuit. It still can be a pure solution displacement operation from the washing

Jan 1, 1961

By A. Eilers

ALTHOUGH the process to which I refer in this paper has been in successful operation for nearly five years, during which time it has been introduced, superseding all other processes having in view the same end, in almost every lead refinery in the country, no description of it, giving economical data, has ever appeared in print, nor has the process been known in its details to any considerable number of engineers beside those conducting it at their works. A discussion of this subject at the present time becomes especially interesting in view of a late publication in the Prussian ministerial organ for Mining and Metallurgy, by Dr. Wedding, in which the method of treating the zinc-silver-lead alloy by distillation, as finally settled upon at Tarnowitz, is very minutely and fully described. It is the more interesting, because in that article reference is made to the American method in an unfavorable light, while, at the same time, it is clear from the article itself, that the most important details of the process, besides the one that it is conducted in black-lead retorts, were not at all understood. In publishing herewith the details of our American method, one of my objects is to invite comparisons between our simple and direct process and the elaborate one at Tarnowitz. In extracting the silver from work-lead by means of zinc, it is always the intention, in this country, to obtain a zinc-crust so rich in silver that the rich lead resulting from subsequent distillation

Jan 1, 1875

By I. C. Runge

This paper outlines in a step-by-step approach all of the major tasks to be undertaken for the design of a complex multi-seam open pit coal mine. Examples are drawn from three such projects in the Hunter Valley of New South Wales, Australia, where computer techniques for equipment production rate estimation, mining block layout, and mine scheduling were used extensively. The paper is divided into two sections - Conceptual Planning and Detailed Planning; and the various tasks associated with these sections are discussed in detail, with examples of typical problems to be overcome.

Jan 1, 1983