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By William H. Morris

At the Glen Summit meeting, the question of controlling the silicon in pig-iron WAS raised; and as this has been deemed by most furnace-men for years past a matter of special difficulty, an account of our experience in the matter may be of interest. When running on mill-iron, some years ago, we aimed to keep

Jan 1, 1893

By H. H. Stoek

The fundamental reasons underlying the choicc of a method of mining a coal seam are safety of operation, cheapness of producing the coal and the character of the product as a saleable article. From the standpoint of safety, open or strip coal mining is always preferable, as many of the dangers inherent to underground work are absent, such as explosions of gas and dust, falls of roof and coal, and also to a great extent those due to haulage and the use of explosives, thus eliminating three of the chief causes of accident from which about 75 per cent. of the underground accidents in coal mines occur. The conditions under which coal is stripped also make the work much safer than ordinary quarry work, as the depth of the pit is usually comparatively small. Prom the standpoint of low mining cost, there is much misapprehension and many of the costs given are misleading in that they do not take into account such items as the destruction of the surface for future use, the full cost of the removal of the overburden, depreciation, amortization, coal depletion, loss of time through floods and from bad weather in winter, etc. Coal is no doubt often put on the cars at less cost by stripping than by underground mining, but by no means always so, as is too generally assumed. In some cases coal must be obtained by stripping or not at all, because the small amount of overburden renders underground mining impossible.

Jan 1, 1918

By A. J. McEvily, R. C. Boettner, C. Laird

The processes leading to fatigue failure in the low-cycle range were studied to obtain an understanding of the basis of Coffin's law. Particular attention was paid to the manner of mack nucleation and to the determination of the portion of the total lifetime spent in crack propagation. It was observed that cracks are nucleated at surface notches meated during reversed plastic deformation, Principally at grain boundaries, and that crack growth occupies greater than 75 pct of the fatigue life. When inclusions are present, they are often the primary sites of crack initiation. From consideration of the incremental distances advanced by a crack in each cycle and of the lifetimes of different materials, it appears that the universality of Coffin's law arises from the similarity of crack-tip strain for a given applied strain amplitude, irrespecti7:e of material. STUDIES of low-cycle fatigue have been particularly rewarding in that a simple correlation between fatigue lifetime and plastic-strain range has been shown to exist. This empirical relationship takes the forml,2 Nner=C [1] where N is the number of cycles to failure, Er is the plastic-strain range defined as the total plastic strain per cycle (the sum of the tensile plastic strain plus the compressive plastic strain), n, the exponent, is a constant independent of the material to a first-order approximation and often has a value of about 0.5, and C is a constant which for a number of ductile and metallurgically stable materials is approximately 0.65 for fully reversed strain.3 This relationship has been shown to be valid for a wide variety of metals and alloys and is often referred to as Coffin's law. However, it is yet not clear why so many different metals and alloys exhibit the same over-all behavior in the low-cycle range. Less is known about the mechanisms of fatigue failure in the low-cycle range than in the high-cycle range, but it is expected that the processes would have much in common. For example, an important characteristic common to both high-and low-cycle ranges is that fatigue crack propagation can occupy a considerable portion of the total lifetime. This has been shown by Laird and smith4 by a count of the number of ripples present on the fracture surface of copper specimens, each ripple corresponding to one cycle of load. On the other hand, some marked differences have been noted. For example, in copper,5 nickel, and aluminum4 there is a greater tendency for grain boundary cracking to occur as the strain amplitude is increased. The purpose of the present work was to study further the processes leading to fatigue failure in the low-cycle range and to obtain an understanding of the basis for the validity of Coffin's law. Particular attention has been paid to the manner of crack initiation and to the determination of the portion of total lifetime spent in crack propagation. MATERIALS A number of metals and alloys were tested, although more attention was focused on a particular few, once general trends had become apparent. Alloys were selected so as to investigate the effects of crystal structure, number of phases, stacking-fault energy, and impurity content. The materials in this grouping were: high-purity copper OFHC copper 1100 aluminum (commercially pure) 70-30 brass (Cu-30 wt pct Zn)

Jan 1, 1965

By John Birkinbine

Four meetings of the Institute have been held in the anthracite coal-fields of Pennsylvania, and excursioris into the district, in connection with meetings elsewhere, have familiarized our members with

Jan 1, 1892

By Ernest F. Burchard

PAGE. I. Introduction,........... 75 II. Outline of the Geology......... 76 1. Stratigraphy............ 76 A. Clinton Formation........ 77 2. Structure...........82 3. The Ore..........85 A. Character............ 85 B. Geographic Distribution....88 III. Local Descriptions........... 88 1. Birmingham District.......... 88 A. Topography and Its Relation to Industrial Development... 88 H. Distribution and Structure of Formations.... 89 C. Divisions of the Birmingham District. 95 Division A (Description of the Ore-Beds), . 95 Division B.........105 Division C.......... 106 Division D,..107 Division E,...........108 Division F........ 111 Division C.......... 112 D. Mining .Development.... 113 2. Northeast Alabama........114 IV. Possible Origin oF the Ore......... 119 V. Relation of Origin to Quality and Extent of Ore... 122 VI. Estimates of Ore-Reserves,......... 125 1. Method of Making Estimates......... 125 2. Data and Results....126 VII. Production and Consumption oF IRon-ORe,.... 132 I. Introduction. Brief and interrupted studies of the Alabama Clinton iron-ores have been made within the last four years by members of the IT. S. Geological Survey. Reports on the progress of this

Jan 1, 1910

By C. P. Sandberg

Notwithstanding the growing importance of this subject, no work specially devoted to it has hitherto been published. Having had to inspect during the last twenty years nearly a million tons of iron and steel rails for various countries, I have obtained experience of what rail manufacturers can practically execute, as well as of what railway engineers practically require. Bearing these two points in mind, I have from time to time published observations with a view to unite both interests,—that of the producer and that of the consumer,—and to reduce the specifications and the forms of sections to standards, or types, in order to facilitate the execution of the works and to improve the construction of permanent way. The Swedish government railways, as well as private companies owning railways in Sweden, Norway, and Denmark,.have during the time above mentioned consulted with me and intrusted to me their rail inspection. I therefore owe to these countries much of the opportunity which I have enjoyed of gaining experience and position. Next to Sweden, America is the country which has most liberally favored me with its confidence in placing these matters in my hands. Through circumstances not under my control there has been little exportation to, and less work done by Europe for, America during the last six years; but the recent revival of the rail trade has been the more gratifying to mo, seeing that almost all the importers of American rails are still specifying for the Sandberg rail sections and inspection. It is therefore with feelings of gratitude that I now beg to lay before the American Institute of Mining Engineers, and I hope, through that body, before the American railway world, the results of some experience which I have gained in the execution of work for their country, and which therefore belongs rightfully to

Jan 1, 1881

By C. P. Sandberg

INTRODUCTION. NOTWITHSTANDING the growing importance of this subject, no work specially devoted to it has hitherto been published. Having had to inspect during the last twenty years nearly a million tons of iron and steel rails for various countries, I have obtained experience of what rail manufacturers can practically execute, as well as of what railway engineers practically require. Bearing these two points in mind, I have from time to time published observations with a view to unite both interests, -that of the producer and that of the consumer,-and to reduce the specifications and the forms of sections to standards, or types, in order to facilitate the execution of the works and to improve the construction of permanent way. The Swedish government railways, as well as private companies owning railways in Sweden, Norway, and Denmark, have during the time above mentioned consulted with me and intrusted to me their rail inspection. I therefore owe to these countries much of the opportunity which I have enjoyed of gaining experience and position. Next to Sweden, America is the country which has most liberally favored me with its confidence in placing these matters in my hands. Through circumstances not under my control there has been little exportation to, and less work done by Europe for, America during the last six years ; but the recent revival of the rail trade has been the more gratifying to me, seeing that almost all the importers of American rails are still specifying for the Sandberg rail sections and inspection. It is therefore with .feelings of gratitude that I now beg to lay before the American Institute of Mining Engineers, and I hope, through that body, before the American railway world, the results of some experience which I have gained in the execution of work for their country, and which therefore belongs rightfully to

Jan 1, 1881

By P. W. George

This paper presents geological data regarding deposits of over 7,500,000 tons of fine-grained sulphide ore in barite gangue. A series of pyroclastics and arkoses was intruded by sills of quartz porphyry in connection with batholithic intrusions of granite 3 miles from Buchans. Gentle folding, with fracturing acid shearing of tuff beds and intruded quartz porphyry, accompanied and followed the intrusion of granite and porphyry. The sulphide-barite mineralization is localized primarily in fractured and sheared tuff beds, but also in the sheared quartz porphyry. Two structures have proved particularly favorable for mineralization-one, the center of an anticline; the other, a series of weak, incompetent tuff beds intruded by thin sills of quartz porphyry and located between strong beds of arkose. During the folding the weak tuff with intruded quartz porphyry was intensely sheared and contorted and subse-quently mineralized by sulphides and barite.

Jan 1, 1937

By Leo P. Tarasov

Magnetic torque studies of ferromagnetic single crystals have been carried out in a number of laboratories during the last decade&apos;s2 and some work has been reported on polycrystalline material showing preferred orientation. Goss3 used the method extensively in developing electrical sheet with desirable magnetic properties, but he used it as a control rather than as a means of studying the texture. Bozorth4 made a quantitative correlation of a torque curve he obtained from some cold-rolled iron with the texture as determined from X-rays, but did not extend his studies beyond the one specimen. Other studies, which have been reported from time to time2,5 have also been incomplete in the sense that no effort was made to study a whole series of samples, differing only in degree of cold reduction or in the annealing temperature, in order to ascertain the effect of such treatments on the texture as revealed by torque measurements. It is the purpose of this investigation to make such a study, mainly in order to see how useful the method can be made when used under favorable circumstances and to find what kind of a correlation can be expected between magnetic and X-ray studies of texture. Before proceeding further, it is desirable to say a little about single crystals, so as to make clear the concepts involved in magnetic torque measurements. Magnetic Torque Method It is fairly well known nowadays that single crystals of ferromagnetic substances have directions of easy magnetization and of hard magnetization. In Fig. 1 are reproduced typical magnetization curves for a single crystal of iron, which show that in a < 100 > direction saturation occurs at low fields compared to those required to saturate the same crystal in a <110> or a <111> direction. (The magnetization intensity I is defined by the equation B = H + 4pI.) At fields high enough to

Jan 1, 1939

By Leo P. Tarasov

Magnetic torque studies of ferromagnetic single crystals have been carried out in a number of laboratories during the last decade&apos;s2 and some work has been reported on polycrystalline material showing preferred orientation. Goss3 used the method extensively in developing electrical sheet with desirable magnetic properties, but he used it as a control rather than as a means of studying the texture. Bozorth4 made a quantitative correlation of a torque curve he obtained from some cold-rolled iron with the texture as determined from X-rays, but did not extend his studies beyond the one specimen. Other studies, which have been reported from time to time2,5 have also been incomplete in the sense that no effort was made to study a whole series of samples, differing only in degree of cold reduction or in the annealing temperature, in order to ascertain the effect of such treatments on the texture as revealed by torque measurements. It is the purpose of this investigation to make such a study, mainly in order to see how useful the method can be made when used under favorable circumstances and to find what kind of a correlation can be expected between magnetic and X-ray studies of texture. Before proceeding further, it is desirable to say a little about single crystals, so as to make clear the concepts involved in magnetic torque measurements. Magnetic Torque Method It is fairly well known nowadays that single crystals of ferromagnetic substances have directions of easy magnetization and of hard magnetization. In Fig. 1 are reproduced typical magnetization curves for a single crystal of iron, which show that in a < 100 > direction saturation occurs at low fields compared to those required to saturate the same crystal in a <110> or a <111> direction. (The magnetization intensity I is defined by the equation B = H + 4pI.) At fields high enough to

Jan 1, 1939

The Naval Consulting Board is asking the aid of all the members of the Institute in its effort to help solve the submarine problem. Probably every member of the Institute has some suggestion, and while each one of these may be of only slight value in furnishing the remedy, the aggregate may be of great service. Every member of the Institute will soon receive a pamphlet known as Bulletin No. 1 of the Naval Consulting. Board of the United States in which full information and instructions will be given to all of those who are willing to assist. It is hoped when this information is received the members of the Institute will give it their prompt attention and write as soon as possible to the Secretary of the Naval Consulting Board, 13 Park Row, New York, N. Y.

Jan 9, 1917

By George S. Rice

DEFINITE data on the amplitude and effect of ground movement in specific mineral formations, caused by various methods used in the mining of ores, coal, and nonmetals, or in the extraction through wells of petroleum, sulphur, and soluble salts, are increasingly needed because of legal liabilities from damage to overlying or adjacent properties, and growing concern as to the conservation of national mineral resources. Not since the committee was established in 1923 has it been so difficult to get technical papers giving ground movement and subsidence data from specific mine operators. The reasons given, as above indicated, are pending or threatening lawsuits. There are three major objectives in ground movement and subsidence studies : (1) Maximum recovery of a mineral resource. (2) Minimizing damage to surface structures, highways, railroads, and agricultural lands caused by caving or subsidence, which may in some situations, as along the Gulf of Mexico shore, cause flooding by surface waters. (3) Lessening damage to overlying or adjacent mineral by back-filling of mine excavations as completely as possible.

Jan 1, 1940

By R. A. Falconer, H. L. Lovell

With increasing requirements for fine coal cleaning and the many advantages of the cyclone operating on a coal-water slurry, a series of studies designed to achieve an enhanced understanding of the cyclone parameters has been pursued. The purpose of this investigation has been to vary a series of dimensional parameters with an experimental 15-in. diam hydro-cyclone, and to determine the relative effects of parameter variations upon ash and sulfur removal. This study of the hydrocyclone is a continuation of a series of investigations, conducted in the Dept. of Mineral preparation at The Pennsylvania State University, which are directed toward the removal of ash and sulfur constituents from fine bituminous coal by size-density separations in cyclones, and toward a fuller understanding of the complex mechanisms involved in such separations. The purpose of this investigation has been to vary a series of dimensional parameters with an experimental 15-in. diam hydrocyclone, and to determine the relative effects of parameter variations upon ash and sulfur removal. Of special interest was the response to cone angle variation, since it is the high included cone angle that generally distinguishes the hydrocyclone as a gravity separator rather than a classifier. DESCRIPTION OF THE HYDROCYCLONE Fig. 1 is a dimensional drawing of the hydrocyclone used in the investigation. The unit was designed and fabricated by Heyl and Patterson, Inc., for experimental use. The dimensional parameters considered were: 1) Three cone sections having included angles of 45, 60, and 95,degrees, 2) Three 3 1/8 in. diam vortex finders having lengths of 15, 17, and 19 1/2 in., 3) Three 4 1/16 in. diam vortex finders having lengths of 15, 17, and 19 1/2 in. 4) Two apex sections having diameters of 2 and 2 1/4 in. The feed inlet orifice had a fixed diameter of 3 in. The hydrocyclone test installation was made at The Pennsylvania State University pilot plant at Barnes-boro, Pa., which operated at 50 tph. During the period that the hydrocyclone was tested, research was in progress at the Barnesboro site to reprocess refuse material from a near-by coal preparation plant in

Jan 1, 1968

By S. H. Ash

More than 100 minerals are mined and processed in the U. S. Management and labor have negotiated wage-scale agreements that have balanced wages and affected cost of labor in such a manner that comparisons can be made of transportation costs. Transportation of materials underground has become of vital importance. This report describes underground haulage methods and equipment, presents cost analyses, and discusses future plans for underground transportation in metal mines. It does not cover hoisting in shafts or slopes by cage, skip, or cars. Advancements have been made by the metal mining industry in lowering transportation costs in several mines, making it possible to mine orebodies or portions of orebodies not considered economically recoverable a few years ago. Numerous reports have been written on transportation at metal mines; this report covers recent haulage at some representative mines throughout the U.S. The term metal mine is used to include all noncoal mines from which up-to-date information was obtainable.

Sep 1, 1956

THE book covers principally the assaying of silver and gold and the determination of these values in ores, sweepings, and base metal. It seems to have been written more for the goldsmith and jeweler than for the primary producer of metals. There were approximately sixty different substances needed in the operations described and not over a dozen different types of raw material (ore, matte, crude or alloyed metal) are mentioned. The methods of separation used were essentially simple and reasonably reliable, though the processes were not sufficiently understood to permit the selection of the simplest effective ingredients, and there was a great tendency to employ complicated fluxes, with unnecessary repetition of long-continued heatings indicative of a leisurely pace of life. Practically all the processes described are based on a few chemical facts: the inability of gold to combine with sulphur, while silver and the base metals form easily fusible sulphides; the ready oxidation of base metals; and the ii- solubility of gold in nitric acid. Fluxes serve to make earthy impurities fusible, and to carry oxidizing or sulphurizing ingredients. Many of the processes of assaying had changed little up to the beginning of the present century. Even as late as 1924, when the writer took a University course in fire assaying, the crucibles, cupels, scorifiers, molds, and tongs were identical with those of the sixteenth century, though the wind furnace had a stack on it and the muffle for cupelling was gas-fired.* The fluxes were purer, but of the same essential composition. That this branch- or twig-of metallurgy had not advanced in any funda-

Jan 1, 1949

By B. D. Cullity, S. S. Hsu

The stress distribution at the surface of a twisted cylinder is analyzed along the boundary of a slip plane of arbitrary orientation and this analysis is applied to the torsion of cylindrical crystals of magnesium. A criterion for slip is developed and the critical resolved shear stress of magnesium in torsion is found to be 0.038 kg per sq mm. The mechanism of torsional deformation in magnesium and aluminum is described, as well as the relaxation of a twisted crystal at elevated temperatures. THERE has been considerable fundamental study A of the mechanism of slip occurring during deformation in tension and compression but comparatively little attention has been paid to the mechanism of torsional deformation. This paper is concerned with the way in which a single crystal deforms in static torsion and with the phenomenon of untwisting which a twisted crystal undergoes during annealing. Particular attention is paid to the application of the critical resolved shear stress law to torsional deformation. Probably the most likely mode of torsional deformation that can be imagined consists of rotation of one part of the crystal relative to another on the active slip plane. Here the most interesting feature is the slip direction. If a cylindrical single crystal is twisted about its axis and if, to consider the simplest case, the active slip plane is normal to the specimen axis, then the direction of gross slip at any point must always be at right angles to the radius drawn to that point. It follows that the crystallographic direction of slip must be continually changing, in sharp contrast to slip in tension which occurs in a crystallographically constant direction. Extensive investigations of slip in torsion have been made by Gough and his associates.&apos; They made torsional fatigue tests on metal single crystals belonging to a number of different crystal systems and observed, with a microscope, the appearance of slip lines on the surface and of strain markings on the transverse cross section of cylindrical specimens. They concluded that the critical resolved shear stress law was just as valid in torsion as in tension, in the sense that slip occurred on that plane and in that direction in which the resolved shear stress was a maximum. They also established that the operative slip planes and directions were the same as in tension. They did not, however, measure the critical resolved shear stress in torsion nor, in fact, did they establish that a critical value of the resolved shear stress was necessary for the initiation of slip. Their investigations were, moreover, restricted to torsional fatigue tests which necessarily involve small strain amplitudes. Wilman,&apos; studying crystal growth and the abraded surfaces of crystals, observed crystal fragments

Jan 1, 1955

By John V. Beall

THIS is not simply the story of how a water filled shaft was developed into a million-ton- a-year producing mine in the space of four critical years, although it is reason enough for telling it, but it is also the saga of an engineering achievement in which knowledge nurtured by years of experience in coal and ore mines was blended together and the best from each type of mining selected. The entire system of mining was detailed on maps by the mining engineering department before the shaft was unwatered, and subsequent development followed these plans nearly to perfection. The selection of machinery was particularly critical as it was necessary to push production from only a few headings in the early stages of development and metal mine machinery was being used in a coal panel-system of mining.

Jan 12, 1950

By Franz Wever

ACCORDING to Tammann,1 the explanation of the effect of mechanical deformation in producing changes in the properties of metals is one of the most important problems of physical metallurgy, taking rank with the study of the constitution of alloy systems; and this problem has long attracted-the attention of practitioner and scientist alike. Its solution was not advanced materially until Tammann2 set up his translation hypothesis with its crystallographic basis, while other hypotheses, such as the amorphous metal hypothesis of Beilby3 and Rosenhain,4 have been shown by more intensive studies to be less and less satisfactory. The principles of the Tammann translation hypothesis have proved to be useful even up to today and in spite of all of the recent accumulation of experimental data, while the differences of opinion which have arisen relate to the extent to which the hypothesis accounts for the observed changes in properties and to what extent further assumptions are necessary. Stimulated by the proposals of Tammann, there soon developed a lively experimental activity which aimed at the elucidation of the structural or crystallographic changes produced by the mechanical deformation of metals. Parallel movements of crystal "blocks" along definite crystal slip planes had already been observed by lowing and Rosenhain5 in 1900, in metals which had been moderately deformed but without shedding light on the crystallographic nature of the processes accompanying more severe deformation. The solution of this important problem was not advanced until a much later date, or until the methods of X-ray crystal analysis had become available. Shortly after the discovery of the diffraction of X-ray by crystals, symmetrical diffraction effects were

Jan 1, 1931

By Charles White Merrill, James W. Pennington

No metallurgical process developed in the 20th century compares with froth flotation in its effect on the mineral industry. Processes like gravity - concentration, amalgamation, and pyrometallurgical reduction are of ancient origin; others like cyanidation and electrolytic reduction were well established by 1900. Such metallurgical processes as heavy-media separation, ion-exchange, and solvent extraction belong to this century, but their influence is small compared with froth flotation. Data collected by the U. S. Bureau of Mines* in a canvass of 202 froth flotation plants reveal that, in 1960, 198- million tons of material was treated to recover 20-million tons of concentrates which contained approximately $1 billion in recoverable products. SIGNIFICANCE OF FLOTATION Froth flotation as described in this chapter refers to a wet process for separating properly ground mineral particles into two or more products. It involves the separation of mineral particles from each other in a liquid pulp by means of air bubbles. Finely crushed ore is agitated in water with the addition of air or other gases. Various chemicals and oils are added to cause the selected mineral particles to attach themselves to the air or gas bubbles. These bubbles, carrying the mineral particles, rise to the surface where they are removed in a froth, while the other particles remain suspended in the pulp. The earliest flotation divided the raw material into two products: a bulk concentrate that was removed as a froth and a tailing that remained in the flotation machine. The froth usually contained the valuable constituents. The successful application of such a process depended on the recovery of a single concentrate from which one or more valuable constituents could be recovered by a chemical or smelting process. With the advance of the art, however, the principle of selective flotation, by which two or more relatively pure products could be recovered from complex raw materials, was evolved. Other chapters in this volume describe the developments during the last 50

Jan 1, 1962

Discussion of the paper of M. B. YUNG, presented at the Pittsburgh meeting; October, 1914, and printed in Bulletin No. 93, September, 1914, pp. 2451 to 2458. T. T. READ, New York, N. Y.-I might .point out that this paper of Mr. Yung&apos;s is on a field that is comparatively little known. It is not as well known as the Kochiu tin field, of Yunnan, which is probably the third . in tin output of the world. This field under discussion is considerably further west and the tin which is produced here is, according to Mr. Yung, of somewhat higher grade than the Yunnan tin, and is used by the refiners at Hong Kong to improve the grade of the Yunnan tin. Most of you know that the tin from the Yunnan is shipped to Hong Kong, where it is refined and shipped to Europe. Mr. Yung points out that the Fu Chuan deposits are entirely alluvial and not found in any veins. They .differ in that from the Kochiu deposits, which Leclere says are "nullement alluvionels; leur origéne filonienne est de plus evidentes." Granite is the country rock here; doubtless the tin occurred in veins in the granite, and the deposits have resulted from the disintegration of the granite. This is a country of strong erosive agencies. The country is semi-tropical, and the rainfall is heavy, so that one would naturally expect deep surface erosion of this kind.

Jan 4, 1915