Search Documents

* George M. Humphrey, president of the M. A. Hanna Co. and of the Iron Ore Co. of Canada, has announced arrangements for financing the development of the Labrador-Quebec iron ore deposits in the total amount of $200 million. Plans call for immediately beginning the construction of mining, railroad, and handling facilities, and contemplate the start of ore shipments in 1955 which will reach 10 million tons a year shortly thereafter. Total drilled and proven ore now exceeds 400 million tons of high grade open-pit ore with prospects for large additional tonnages. Capital structure of the company authorizes up to $125 million of first mortgage bonds, $40 million of income debentures and $60 million of common stock.

Jan 12, 1950

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and visitors who registered at Institute headquarters during November: George W. Otterson, Mauson, B. C. Roy H. Allen, Chihuahua, Mexico. E. L. C. Ayres, Bound, Brook, N. J. George A. Packard, Boston, Mass. M. Russell, Bound Brook, N. J. Richard C. Patterson, Jr., Kansas City,,Mo. Carlo Spruyt, Antwerp, Belgium. Francis C. Phillip, Pittsburg, Pa. Charles A. Pringle, San Francisco, Cal. M. H. Kuryla, Mexico City, Mexico. E. S. Bardwell, Great Falls, Mont. Arthur Chippendale, Mexico City, Mexico. Sir Robert Hadfield, London,, England. F. Danvers Power, Sydney, Australia. James A. Barr, San Francisco, Cal..

Jan 12, 1913

Organization Place Date 1918 Institute of Metals Division, A. I. M. E Milwaukee, Wis. Oct. 8-11 Iron and Steel Members, A. I. M. E Milwaukee, Wis. Oct. 8-10 American Foundrymen's Association Milwaukee, Wis. Oct. 7-12 American Museum of Safety and Sanitation, Exposi- tion St. Louis, Mo. Oct. -7-12 National Safety Council St. Louis, Mo. Oct. 14-17 Business Show : New York, N. Y. Oct. 21-26 National Society of Naval Architects New. York, N. Y. Nov. 14-15 American Society of Mechanical Engineers New York, N. Y. Dec. 3-6 Geological Society of America Boston, Mass. Dec. 25-31 American Association for the Advancement of Science Boston, Mass. Dec. 27-Jan. 2. 1919

Jan 10, 1918

By M. Gell, G. R. Leveran

The high- and low-cycle fatigue properties of the nickel-base superalloy, Mar-MBOO, in columnar-grained and single-crystal forms were determined at room temperature. It was found that the fatigue lives of these materials were greatly affected by the size of preexisting cracks in MC-type carbides contained in the micro structure. Most of the data falls on two curves given by: (zN)'/A€= K, where Nf is the number of cycles to failure, Af is the total strain range, and K is a function of carbide size. No difference was observed in the fatigue behavior of the columnar-grained and single-crystal materials for the same MC carbide size. Matrix slip and crack initiation occurred at precracked MC carbides and, to a lesser extent, at micropores. Fatigue crack propagation was mainly in the Stage I mode, i.e., on cry stallo graPhic slip planes. The Stage I fracture in these materials was unusual in that distinct features were observed on the fracture surfaces. In high-cycle fatigue, these features resembled those commonly observed on the cleavage fracture surfaces of bcc and hcp materials. Yet, in this study, the cracks propagated slowly in a cyclic manner. In low-cycle fatigue, the Stage I facets contained equiaxed dimples, similar to those observed on the tensile fracture surfaces of ductile materials. These observations indicate that both local normal and shear stresses are involved in these Stage I fractures. A model is proposed to explain these results based on the weakening of the cohesive energy of the active slip planes by reversed shear deformation and the fracture of the bonds across the weakened planes by the local normal stress. RECENT developments in casting technology have produced cast nickel-base superalloys in columnar -grained and single-crystal forms.1'2 The tensile and creep properties of the nickel-base superalloy, Mar-M200, cast in these forms have been shown to be superior to the corresponding properties of the conventionally cast polycrystalline material.lp2 This improvement in properties results, in part, from the elimination of grain boundaries in the single crystals and the alignment of the grain boundaries parallel to the stress axis in the columnar-grained castings. As part of a program to evaluate the fatigue properties of nickel-base superalloys cast in single-crystal and columnar-grained forms, a study has been made of the cyclic deformation and fracture of Mar-M2OO at room temperature. M. fiFl I .hininr Mpmher AIMF ic ^pninr Rocoarrh Accn^iata anH I) EXPERIMENTAL PROCEDURE The composition range of Mar-Ma00 in weight percent is: 8 to 10 Cr, 9 to 11 Co, 11.5 to 13.5 W, 0.75 to 1.25 Cb, 1.75 to 2.25 Ti, 4.75 to 5.25 Al, 0.01 to 0.02 B, 0.03 to 0.08 Zr, 0.07 to 0.12 C, bal. Ni. All of the castings met the above specifications. The castings were solutionized for 1 to 4 hr at 2250°F followed by aging at 1600°F for 32 hr which resulted in a 0.2 pct offset yield stress of 150,000 psi at room temperature. The microstructure of the material consisted of cuboidal, coherent particles of ordered, fcc Ni3(A1,Ti) (commonly designated y'), approximately 0.3 p on edge, distributed in an fcc y solid-solution matrix. MC carbides together with shrinkage and gas micropores were also distributed throughout the materials. The MC carbides and micropores were located preferentially in the interdendritic interstices, as well as in the grain boundaries in the columnar-grained castings. The (100) direction of all the single crystals and the common (100) axis of the grains in the columnar materials were aligned within about 5 deg of the specimen axis. Fatigue testing was carried out in the high-cycle (HCF) and low-cycle (LCF) fatigue regions, with the major difference being gross yielding of the specimen occurred during the first cycle in the LCF region. This division also corresponded with the more usual one in which the life of a specimen in LCF is less than lo4 cycles and that in HCF is greater than lo4 cycles. The designs of the high-cycle fatigue and low-cycle fatigue specimens are shown in Figs. l(a) and (c), respectively. The gage sections of both HCF and LCF specimens were electropolished prior to testing. The HCF specimens were tested in an MTS, closed-loop, hydraulic fatigue machine at 10 cps in air. The specimens were cycled between a tensile stress of 5000 psi and a maximum tensile stress which ranged from 35,000 to 125,000 psi, Fig. l(b). The LCF specimens were cycled under strain control from zero to a maximum tensile strain, Fig. l(d), in a Wiedemann-Baldwin testing machine. The experimental procedure has been described elsewhere.3'4 Both HCF and LCF tests were interrupted periodically in order to replicate the development of slip and cracking at the specimen surface. This was accomplished by placing plastic replicating tape around the gage section of the specimen while the specimen was in the mahine. The size of the MC carbides for all specimens was measured on a polished longitudinal section through the gage section after fatigue testing. The method of measurement consisted of carefully scanning the entire polished section in order to locate the largest MC carbides. Photographs were then taken of the six longest carbides oriented approximately normal to the

Jan 1, 1969

By M. S. Azun

M.S. Azun I have many objections to the content of the author's paper. Before discussing it, however, I would like to repeat the property of semivariogram function. Second order stationary properties of regionalized variables (ReV's) such as semivariogram function ?(h) are perfectly known in geostatistics. Also, the kriging equations in the language of mathematical statistics using second order stationary properties are well understood. However, the way to use the sample (estimated) semivariogram function in any one of the kriging procedures is vague. The sample semivariogram function is given as follows: [1 N-hy*(h) = 2(N h) i21 {Xi-Xi+h}Z, h=0, 1, N-1] where N is the total number of samples, Xi is the sample value at the i - th location, X i+h is the sample value at the i +h - th location, and h is the distance among the samples. An estimation variance of sample semivariogram function of first lag is smaller than that of higher order lag. The theoretical semivariogram function reaches the variance of samples asymptotically. But this is not easily observable because of the larger variation involved in the estimate of semivariogram function. In general, an estimation procedure is done for h = 0, 1, 2,…., up to the greatest integer less than N/2, even though sample semivariogram function can be computable through N-1. After estimating semivariogram function, the critical question of how to model sample semivariogram function arises. As seen in the above equation, sample semivariogram function is discrete and can be smoothed by the model being selected. Therefore, modeling of sample semivariogram function is the most important step in geostatistics. It not only smoothes a discrete function but also affects the results of the kriging procedure. When the only aim is to model the semivariogram function, which is the basic point of the author's paper, one can employ any fitting techniques, such as curve fitting, or any ar¬bitrary functions, which are called submodels in the paper. The term "arbitrary function" is used rather than "submodel" because there is no basic understanding of developing them. The author suggests that the sum of those submodels can also be used for the modeling of sample semivariogram function. The combination of any arbitrary functions brings many problems instead of giving an insight of the domain structure considered. The author used two arbitrary functions and the nugget effect in response to sample semivariogram function (Fig. 10). For the same example, he stated that the parameters involved in the mixed arbitrary function model can be accepted when the discrepancy between sample semivariogram function and the model is small visually. For verifying the fitting behavior of any selected model, one should not be contented with the visual satisfactory. Some statistical measure such as goodness of fit has to be used. The author's practice is no more than an exercise in curve fitting without any fundamental understanding or conceptualization of the underlying physical mechanism. Furthermore, the selection of any model is not an easy task if the purpose is the search for the "best" response to the observed second order properties of ReV's. I suggest that the Markovian model (Azun, 1983), on the basis of a theoretical understanding of underlying mechanism, which gives more information about the occurrence of regionalized variables, is used to respond all properties of ReV's. There are a lot of problems for modeling of onedimensional sample semivariogram function. Thus, it is not appropriate to go to higher order dimensional sample semivariogram function modeling. In the meantime, I would recommend that one can connect the values of standardized sample semivariogram function rather than simple values of semivariogram function in the two-dimensional estimation. The standardized values can be computed in dividing the semivariogram function value by the number of sample pairs involved in each lag regardless of the directions. In conclusion, geostatistics is an interdisciplinary area in mining that uses the principles of mathematical statistics. Thus, it should not violate any probabilistic and statistical rules. When Matheron was developing the theory of geostatistical study in the early years of geostatistics, many mining people had a reservation accepting the geostatistical tools. However, this does not mean that we, the geostatisticians, might try to convince those people using some "strange" tools or rules as some authors implied (Baafi and Kim, 1984). Instead, we have to develop and explain the geostatistical tools staying only in the framework of statistical concepts and properties. ? References Azun, M.S., 1983, "Stochastic Process Modeling of Spatially Distributed Geostatistical Data," Columbia University, Ph.D. Thesis. Baafi, E.Y., and Kim, Y.C., 1984, "Discussion - Comparison of Different Ore Reserve Estimation Methods Using Conditional Simulation," Mining Engineering, Vol. 36, No. 3, p. 280. Reply by J.M. Rendu The interactive method proposed by Rendu allows practitioners to develop semivariogram models that take into account not only the numerical information obtained by sampling, but also highly significant additional information that often cannot be quantified. The geology of the deposit - including hypotheses concerning its genesis, sampling methods, assaying methods, and mathematical methods used to calculate the semivariograms - all have an influence on the numerical results obtained and on how these results should be interpreted. If all the information concerning the spatial distribution of values in a mineral deposit was contained in the sample values, it could be argued that statistical techniques alone would produce optimum models. However, this is rarely, if ever, the case. Methods that allow the user to take into account his experience and his geologic understanding of the deposit should not be rejected for the sake of theoretical statistical purity. ?

Jan 1, 1986

Trans. Pamphlet Volume Number Title Author Meeting and Page* 1033 Relation of Air Presaure to Drilling H. W. Seamon New York 66, 743. 766 Speeds of Hammer Drills . Feb. 1921 1034 Time Factor in Depletion of Mines J. W. Roberts New York 66, 711 Feb., 1921 1035 Calculation of Ore Tonnage and Grade J. E. Harding New York 66, 117, 122 from Drill-hole Samples Feb., 1921 1038 Diacuasion of Papers Presented in 1920 1041 Run-off and Mine Drainage H. N. Eavenson New York 66. 624. 630 Feb.. 1921 1043 The Health of the Underground Worker A. J. Lanza New York Feb, 1921 1045 Dust-ventilation Studies in Metal D. Harrington New York 66, 272, 288 Mines Feb., 1921 1046 Discussion of Papers Presented at New York Meeting, 1921 1072 Breakage and Heat Treatment of Rock- B. F. Tillson New York 66. 758 drill Steel Feb., 1921 1073 Discussion of Papers Presented at New York Meeting, 1921 1076-M Analysis of Some Drill-ateel Teats F. B. Foley New York 66,789 Feb.. 1921 1077-M Application of Magnetic Analysis to C. W. Burrows New York 66, -796 Rock Drills Feb., 1921 1078-M Heat Treatment of Rock-drill Steel G. H. Gilman New York 66.779 Feb., 1921 1080 What is the Ideal Drill Steel? F. H. kingdon New York 66, 807 Feb.. 1921 1081 Rock Drill-Steels, etc. W. T. Ober New York 66,814 Feb.. 1921 1082-C Underground Mine Development, Its J. B. Dilworth Wilkes-Barre 66,715, 761 Definition and Valuation Sent.. 1921 1081 Drill Steel from Hollow Ingots P. A. E. Armstrong New York 66,809 Feb., 1921 1068 Authors' Replies to Recent Discussion 1092 Heat Treatment of Rock Drill Steel A.E.Perkins New York 66,811 Feb., 1921 1096-M Octagonal Ventilation Shaft of Davis- J. L. Bruce Wilkes-Barre 66. 252, 608 Daly Copper Co. Sept., 1921 1100-C Determination of Electrical Equip- G. Bright Wilkes-Barre 66,580,606 ment for a Mine Hoist Sept., 1921

Jan 1, 1927

PRESIDENTS DAVID THOMAS 1871 Born November 3, 1794, Cadoxtan, Glamorganshire, South Wales. Died in 1882. Attended schools in Wales. Came to America in 1839. A.I.M.E.: Member, 1871; Honorary Member. Iron manufacturer; inventor. Built first anthracite fired hot-blast furnace in America. Known as the "Father of the Lehigh Valley." President, Catasauqua and Fogelsville Railroad; Director, Lehigh Valley Railroad; Founder, Thomas Iron Co. and St. Luke's Hospital at Bethlehem, Pa.; Trustee, Lafayette College.4 ROSSITER WORTHINGTON RAYMOND 1872-1874 Born April 27, 1840, Cincinnati, Ohio. Died in 1918. Brooklyn Polytechnic Institute, 1857; Lafayette College, Ph.D., 1868; Lehigh University, LL.D., 1906; University of Pittsburgh, Hon. LL.D., 1915., Gold Medal, Institution of Mining and Metallurgy (London). A.I.M.E.: Founder, Member of 1871; Vice President, 1871, 1876-1877; Secretary, 1884-1911; Secretary Emeritus, 1911-1918; Honorary Member. Consul¬ing mining engineer; practicing lawyer, sailor, soldier, writer, orator, editor, theologian, teacher, novelist, chess player. Recognized as the "Grand Old Man of the Institute." ALEXANDER LYMAN HOLI,EY 1875 Born July 20, 1832, Lakeville, Conn. Died in 1882. Brown University, 1853; Hon. LL.D., 1878. A.I.M.E.: Member, 1871; Vice President, 1874; Manager, 1877-1879. Bessemer Medal (Iron and Steel Institute, London), posthumously. Brought bessemer process to United States. A statue was erected in Washington Square in his memory and presented to the City of New York in 1889. The inscription notes: "foremost among those whose genius and energy established in America and improved throughout the world the manufacture of bessemer steel." ABRAM STEVENS HEWITT 1876 Born July 31, 1822, Haverstraw, N. Y. Died in 1903. Columbia University, 1842; Hon. LL.D., 1887. A.I.M.E.: Member, 1871; Manager, 1872-1875. Bessemer Medalist and Honorary Member, Iron and Steel Institute (London). Gold Medal, Chamber of Commerce of New York City. Philanthropist, lawyer, statesman, publicist, pioneer in the iron and steel industry. Mayor of New York City in 1887. Business partner of Peter Cooper, Executive Manager of Board of Trustees, Cooper Union, New York City.

Jan 1, 1947

William M. Courtis, Detroit, Mich. (communication to the Secretary*):—I have a few items to add to the history of the Lake Valley mines. In December, 1879, I was sent to the Bassic mine of Colorado and then to Lone mountain, near Silver City, N. M., and to various copper-camps in Arizona. I staged from Glorietta, N. M., to Tucson, Ariz., stopping at Silver City to see the Cosette mine. This mine led to the opening of the Lake Valley mines, and is a deposit of similar formation. New Year's day, 1880, found me crossing the Rio Grande above the Jornado del Muerto. At Aleman, Victorio's band crossecl four hours ahead of us. We picked up four wounded soldiers to take to Fort Bayard, for during the day the colored troops under General Hatch had been driving the Indians back through the San Andreas mountains. The traveler of to-day little realizes the dangers of these trips, when over very rough roads we made about 100 miles in a day and a night. I subsequently made this trip six times, up to 1882, and each time I missed an Indian attack by from one to four days. The day I arrived at Silver City news had come of the massacre of 75 women and children at the San Francisco ranch. The fighting-men of' Silver City had gone to rescue others. I was the only passenger from Socorro, N. M., until we picked up the soldiers. The next day we came suddenly on 5 of Victorio's band, but we had picked up several miners, so our stage bristled with guns, and we mere let alone. At or near my stone quarry, 6 miles from Socorro, 9 men, were killed by the band that, a day or two after, killed George. Daly, Lieutenant White, and all their men. During this raid, our miners and women at the mine slept in the tunnel. At the Cosette mine I had 35 men at work. These Indian raids had

Jan 1, 1910

Discussion of the paper of Frank H. Kneeland, Safeguarding the Use of Mining Machinery. By B. F. Tillson and Arthur Williams. 1073 Discussion of the paper of Howard N. Eavenson, Safety Methods and Organization of United States Coal & Coke Co. By William H. Grady, Thomas W. Dawson, C. W. Goodale, J. Parke Charming, B. F. Tillson, George S. Rice, Arthur Hovey Storrs, Harry H. Stoek, Lawson Blenkinsopp, Arthur Williams, and Howard N. Eavenson. 1075 Discussion of the paper of J. Parke Channing, Enlarging the Worth of the Worker and the Perspective of the Employer. By Fred H. Rindge, Jr., S. A. Taylor, Elmer L. Corthell, and Philip W. Henry. . 1095 Discussion of the paper of Walther Mathesius, High Blast Heats in Mesaba Practice. By Joseph W. Richards, W. A. Forbes, J. E. Johnson, Jr., H. P. Howland, and Walther Mathesius. . 1100 Discussion of the paper of W. R. Shinier, Effect of Finishing Temperatures of Rails on Their Physical Properties and Microstructure. By William R. Webster, Henry M. Howe, A. A. Stevenson, G. K. Burgess, and Samuel L. Hoyt . 1107 Discussion of the paper of George K. Burgess and Sir Robert A. Hadfield, Sound Steel Ingots and Rails. By Albert Sauveur, Henry M. Howe, Henry D. Hibbard, Joseph W. Richards, F. W. Wood, and George K. Burgess. . 1112 Discussion of the paper of Henry M. Howe and Arthur G. Levy, Are the Deformation Lines in Manganese Steel Twins or Slip Bands? By J. E. Stead 1116 Discussion of the paper of F. C. Langenberg and R. G. Webber, Structures and Hysteresis Loss in Medium-Carbon Steel. By Henry M. Howe. . . 1117 Discussion of the paper of Charles H. MacDowell, German and Other Sources of Potash Supply. By George S. Rice, Charles H. MacDowell, and V.C. Grubnau . . 1118 Discussion of the paper of Joel H. Watkins, White-Burning Clays of the Southern Appalachian States. By H. Ries 1120

Jan 5, 1915

By H. Warlimont

In recent investigations of the microstructure and crystallographic features of martensite by electgon microscopy,', '9 thin films (about 50 to l000A in thickness) have been used as specimens. It was found by W. Pitschl ,2 that the lattice relationships between the supefiaturated fcc matrix and the martensite formed in thin films were different from those observed after transformation in bulk material. Corresponding differences are to be expected in nucleation and in reaction kinetics in the formation of martensite in thin films, but have not yet been reported. In the course of the preparation of thin films of iron-base alloys for investigation by electron microscopy it was observed that films of alloys, whose martensite formation temperature (Ms) was below room temperature, formed martensite during the electrochemical thinning process conducted at or above room temperature. The chemical compositions and approximate bulkM,-temperatures of the three materials on which this observation was made are listed in Table I. The alloys were vacuum-melted from high-purity metals. It can be seen that the effect occurred in alloys that contain only sub-stitutional components as well as in alloys that contain carbon as an interstitial solute. The appearance of martensite formed in this manner is illustrated in Fig. 1, which represents a polished film of alloy No. 1 at XI0 magnification. The martensite plates can be recognized by their surface relief effects. In addition, heavily strained (owrinkledo) austenite can be seen near the edges of the film where it is thinnest and transformation stresses or strains can be accommodated by plastic deformation most easily. The nonuniform distribution of transformed regions is probably due to the varying thickness of the film. These observations were common to all materials listed in Table I. Because effects of supercooling or straining can

Jan 1, 1962

By D. Foster Hewett

The scope of this paper is the description of two districts in Peru in which deposits of vanadium have been found, and the consideration of much laboratory-work that I and others have done to determine the nature of these deposits. It is with regret that I present some of the data in a state of evident incompletion, particularly the analyses of a few of the minerals, which leaves some doubt as to whether the true nature of the migerals is understood. I make no apology, however, since in this case, as in many others referring to ore-deposits, conclusive opinions cannot be stated until a great amount of work has been done, and the deposit has been thoroughly exploited. I believe that the data and the tentative conclusions here presented indicate a unique and interesting condition which may assist others in work along similar lines; arid further, what is of more practical importance, stimulate a search for a metal which, though long considered rare, is probably so merely because proper care has not been taken to recognize it. An excellent bibliography on the occurrence of vanadium in nature is given by I?. W. Clarke in his paper, Data of Geochemistry;' and in the preparation of this paper 1 have consulted many of the references contained in the Bibliography of the Chemistry of Vanadium, by M. Moisan.2 A brief review of the subject having special reference to the metallurgy of vanadium is contained in the small book by P. Nicolardot.3 One of these vanadium-deposits has already been briefly. 1 Bulletin No. 330, U. S. Geological Survey (1908). 2 Chimie Minerale, vol. iii. (1905). 3 Le Vanadium (1905).

Jan 1, 1910

By C. L. Shapiro, R. Schempp

DuRing the past few years, general interest in the steel-producing and steel-consuming industries has been centered on the so-called "inherent characteristics" of steels. While often vaguely described, these characteristics are known to influence the response to heat-treatment and the hardening characteristics of the material. Although most of the recent papers and discussions have associated the "inherent characteristics" with the austenitic grain size and emphasized the importance of it, comparatively little is known of the variables that may affect the size of the austenite grain. The work to be described in this paper was carried out during the course of a study on the inherent characteristics of tool steel containing one per cent carbon. The discrepancies encountered in the determination and classification of the austenitic grain size led to an investigation of some of the variants influencing the austenitic grain size as determined by standard methods. Methods of Determining Austenitic Grain Size The present methods used for the determination of the austenitic grain size may briefly be classified in two groups: 1. Etching at room temperature to reveal the austenite grain size prior to cooling. 2. Etching at elevated temperatures, cooling to room temperature, and observing the structural conditions that existed at the temperature from which cooling occurred. The outstanding methods of the first group are: (1) the McQuaid-Ehn test, (2) optimum rate of cooling, (3) quenching and etching. McQuaid-Ehn Test.—This established and accepted test does not need much elaboration. It consists of pack carburizing at a definite temperature for a standard period of time and slowly cooling in the furnace. The temperature is 1700" F. (925' C.) and the time is 8 hr. The interpretation and evaluation of this test are fairly well defined in the A.S.T.M.

Jan 1, 1937

By H. N. Eavenson

EaRly in 1917, the United States Coal & Coke Co. secured options on several tracts in Harlan County, Ky., aggregating about 19,000 acres in area, and after careful prospecting by outcrop openings and diamond drilling, completed the purchase late in July of that year. This property is situated in the eastern end of Harlan County, south of the Poor Fork of Cumberland River, and extending across Big Black Mountain to the Clover Fork of Cumberland River, a distance of about 7 mi. (11.3 kg.). It extends from the Kentucky-Virginia line westward for about 6 mi. Looney Creek, which empties into Poor Fork, crosses the property for about 4 mi. (6.4 kg.), and as several of the seams within the property outcrop along this stream, it afforded an easy, and the logical, place for development. The property is on the northern side of the geological trough formed by the uplifting of Stone Mountain, on the southern, and Pine Mountain, on the northern side; the northern boundary along Poor Fork is practically at the base of Pine Mountain. This area has been described in various geological reports. The main seam on this property is the one known variously as the "C," Benham, Keokee, Taggart, and Roda; it is also called, by the Kentucky Geological Survey, the Kellioka seam of the western portion of Harlan County. This seam averages, in this property, about 5 ft. (1.5 m.) in thickness, although local rolls reduce this thickness considerably over small areas, and at the extreme western end of the property the seam splits. It is usually clean, although occasionally a small parting occurs within a few inches of the bottom of the seam; it is one of the best coking and gas coals in the United States. The average analysis of this coal is given in Table 1.

Jan 1, 1922

By A. M. Gaudin

UNTIL recently little attention has been paid to the effect of particle size on flotation. This has been especially true of material finer than 200 mesh.1 Particles of different sizes must behave differently in a flotation circuit; increased information along this line would be of practical use as well as of theoretical interest. The object of this study has been to determine what effect particle size has on floatability. The problem has been approached in two ways. One method consisted in a study of samples of the final products of several mills. These samples were sized and each size-product was analyzed for its important constituents. Bakelite briquettes2 of some of the products were made and studied under the microscope. This investigation is being continued, with particular reference to quantitative microscopic analysis of intermediate products of flotation plants. M In the other method of study, mixtures of pure minerals were ground to different degrees of fineness and floated. The products were then sized and analyzed. A study of the behavior of mixtures of pure sized minerals would have been illuminating, but after trial it was considered impractical on account of the tediousness of the large amount of elutriation required and the fact that the mineral particles would oxidize while being sized, preparatory to flotation. Broadly speaking, the following conclusions have been reached: 1. Results obtained by the two methods of study are in agreement. 2. The usual notion about the relative ease of flotation of very fine particles does not agree with the facts: 3. There is a time sequence of flotation with regard to particle size, the medium coarse particles floating first. 4. No successful method of floating extremely fine pulps has been found. 5. Recovery is optimum in a certain well-defined size range. 6. Selection is optimum in another well-defined size range.

Jan 1, 1931

By J. L. Rodda, M. L. Fuller

In connection with an investigation in this laboratory on the high-zinc side of the copper-zinc system, it was observed that well developed segregate structures of the Widmansttten type were formed when a secondary phase precipitated from the solid solution of copper in zinc. This paper presents an analysis of the crystallographic relationship between the segregate and the solid solution matrix. The data to be presented are an interesting addition to the literature on segregate structures in that the plane of segregation is one of the less densely populated planes. In agreement with the generalization of C. H. Mathewson and D. W. Smith' the plane of segregation in the matrix contains the direction of closest atomic packing of the lattice. Furthermore, the matrix and the segregate are both hexagonal close-packed, which has not been reported hitherto in the 1iternture.l The increasing commercial importance of zinc alloys containing copper makes this fundamental study of value to the metallography of zinc alloys. Zinoeich Copper-zinc Alloys Copper enters into solid solution with zinc to at least 1.8 per cent at 400" C., according to W. M. Peirce.3 The solubility is less at lower temperatures. Thus a solid solution of copper in zinc, saturated at an elevated temperature, will precipitate the excess copper in a separate phase at a lower temperature, conditions of concentration, time, and temperature being suitable. The nature of these two phases has been established by the X-ray method of crystal analysis. Westgren and Phmgmén4 and also Owen and Preston5 have shown that the solid solution eta (7) is of the substitu-tional type with copper atoms replacing zinc atoms on the hexagonal

Jan 1, 1933

By P. S. Rudman

The allotropic volume changes of the ,metallic elements are reviezoed with the conclusion that in general atomic volume is conserved to better than 1 pct in such transformations. A table of the atomic volumes of the metallic elements is given and its use in considering the size factor in alloys is discussed. The importance of the concept of atomic-size factor, due to Hume-Rothery and coworkers,' is firmly established. Most attempts at quantitative formulations of this concept have employed the atomic radius (half some interatomic distance) as the measure of size and innumerable tables of such radii exist. This is probably, however, an unfortunate choice of parameter. Firstly, discussion in terms of interatomic distances requires a knowledge of the crystal structure. While this is known, except for a few cases, for the elemental structures, there are still many undetermined alloy structures. Secondly, except for the simpler structures, face-centered cubic (Al),* body-centered cubic (A2),* and hexagonal-close-packed (A3).* with ideal axial ratio, there is no unique in- teratomic distance, an m y decision must be made as to which distance, or which average of the distances, should be used. However, the most important point is that for metals the dominant bonding parameter can generally be expected to be atomic volume and not interatomic distance. This is perhaps most explicitly stated in the Wigner-Seitz cellular method.' In this approximation, cellular polyhedra of atomic volume v are replaced by spheres of radius Y,: 4/3 ?rs3 = v. That is, there is no reference to the interatomic distances. If atomic volume is in fact the dominant parameter, then in allotropic transformations we might expect to find atomic volume approximately conserved. For example, in the A1 ? A2 transformation we would thus have

Jan 1, 1965

By Jennings S. Cox

(Glen Summit Meeting, June, 1911.) THE following notes, prepared in 1908, as the result of a personal examination and extensive explorations under my direction in 1906, have been revised and greatly augmented after two subsequent visits and further explorations in 191.0. The hard iron-ores of the south coast of Oriente Province, in the island of Cuba, have been known for many years, in fact one mine has been in operation for more than 20 years ; but it is only within the past four years that the large mantle-deposits of brown ores of the north coast have attracted serious attention. A. C. Spencer 1 has described these ores in a paper, entitled Three Deposits of Iron Ore in Cuba, which refers to the Mayari, Moa, and Cubitas deposits. C. M. Weld,2 in a scholarly paper on The Residual Brown Iron-Ores of Cuba, has discussed the character and possible genesis of these deposits with particular reference to the Moa field, calling attention also to the Taco and Navas fields in addition to those described by Spencer. Descriptive articles with reference to the Mayari field, and a few words about the Moa deposit, have also appeared.3 It is the purpose of the present paper to give some account of the exploration of the Moa deposit and to call attention to its commercial importance. LOCATION. The Moa district is situated on the north coast of the . Province of Oriente, which is the most easterly province of the island of Cuba. It lies on the northern or seaward slope of 1 Bulletin No. 340, U. S. Geological Survey, pp. 318 to 329 (1908). 2 Trans., xl., 299 to 312 (1910). 3 Iron Age, vol. lxxx., No. 7, pp. 421 to 426 (Aug. 15, 1907), and vol. lxxxi., No. 15, pp. 1149 to 1157 (April 9, 1908).

Mar 1, 1911

By George K. Burgess

The suggestion has often been made that it would be highly desirable, at least for certain grades of steel, to be able to control more certainly, by pyrometric measurement or otherwise, the temperatures of the operation of the open-hearth and other furnaces used in the manufacture of steel and iron. That the properties of the ingot and finally of the finished steel product are intimately related to the final temperatures attained by the metal in the furnace and to the temperature of casting, has been recognized by metallurgists for a long time, and this question has been very thoroughly treated, especially by Prof. Henry M. Howe, and by A. W. and H. Brearley.1 It is the object of this paper to demonstrate that in so far as casting temperatures of furnaces, steel ingots, and similar operations involving the temperatures of streams of iron and steel are concerned, well-known pyrometric methods may be easily applied—if certain recently determined corrections are made and precautions taken—with a relatively high degree of accuracy. Greater but not insurmountable difficulties will be encountered in the case of open-hearth furnace temperatures, while for those of the converter type a ready solution does not seem practicable. It appears that certain essential data have always been lacking in reporting observations such as those of Le Chatelier in 1892. Thus the correction to be applied for the characteristic radiation—or emissivity— has hitherto not been adequately taken into account nor the limitations of the several possible pyrometric methods clearly recognized. In view of the fact that in open-hearth practice the temperature to be measured in the furnace itself, in the stream of metal and slag and in the teeming into molds or ingots is usually above 1,500" C. (2,700" F.)

Jan 1, 1917

By S. R. Zimmerley, John Gross

The deductions drawn in crushing and grinding operations have heretofore been based on a separation of the products into various sizes. A crushed product may be sized by sieving, by elutriation and by aid of the microscope. To estimate the surface of each size the relation of the surface to the estimated average diameter must be assumed. Such a relation, owing to the irregularity of the particles, may involve two assumptions: First, a factor to convert average diameter to surface for one particular size; and second, a variation in the factor as the diameter of the particle changes. Obviously a surface measurement in which such assumptions and estimates are involved is questionable. In the first paper of this series1 a method has been given by which an accurate measure of surface of quartz can be obtained from its dissolution rate. By the use of this method, surface measurements have been made on a series of sieve sizes of crushed quartz, the results of which are given and discussed in this paper. Prepaeation of the Quartz Sizes The quartz, consisting of large uniform pieces with a density of 2.65 and a purity of 99.5 per cent. SiO2, was crushed to pass 20 mesh and was then sieved. Tyler standard sieves were used, the sieving being done by hand according to the proposed standard method submitted by the senior author to the Milling Committee of the A. I. M. E. A wet split of the sample was made on a 270-mesh sieve. This was followed by dry sieving until less than 0.05 per cent. of the weight of the sample passed through the sieve in 1-min. sieving. The +28-mesh material was discarded because that size did not contain the difficult grains from the 20-mesh sieve.

Jan 1, 1930

E. M. Fitchett (Johnstown, Pa.)—The fact stated by the authors that: "In the laboratory, without marked efficiency decreases, the authors have deposited zinc successfully from solutions containing as high as 1 g per liter of germanium," (p. 465, paragraph 3) is most unusual. A similar statement is made in the summary and conclusions: "Germanium alone, within normal operating limits does not cause large efficiency losses." The limits are not defined. These facts are directly contrary to much of the published history on the effect of germanium in zinc electrolysis. A description of the conditions leading to such a successful electrolysis would be of interest to all engaged in the production of electrolytic zinc. It is unfortunate that the authors of this paper did not determine the actual concentration of germanium and cadmium in the solutions which they electrolyzed after a zinc dust purification. This purification will take out a variable amount of these impurities, depending upon the composition of the dust, type of agitation, presence of activating agents, etc. Probably every electrolytic zinc plant in this country has accurate methods, both wet and spectrographic, for determining germanium and cadmium. These specific methods, adopted from the standard analytical literature, are often available to educational institutions for the asking. The headings of Fig. 2 and of the two tables, with their definite concentrations of germanium and cadmium (which are not so definite according to the footnotes) could possibly be somewhat misleading, since the actual amounts of germanium and cadmium present during electrolysis are not known. Even the 1 hr electrolysis time might be too short for a study of this type; 12 or 24 hr tests might be much better. Commercial solutions have been known that gave over 90 pct ampere efficiency during the first hour of electrolysis, but no metal at all after 24 hr.

Jan 1, 1953