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By Cyril Wells, Paul E. Busby, Donald P. Hart

EARLY workers in the field have established that the diffusion of nitrogen follows normal diffusion laws. Concentration-penetration data from layer analyses of reasonably pure iron specimens nitrided in an atmosphere of CO-NH, are given in the literature,' and were utilized to calculate diffusion constants for nitrogen. The diffusion of nitrogen in y-iron may be represented approximately by the equation D - 1.07x10-' e-:".'m'"'r The diflusion coefficients, D, given by this relation represent mean values, since carburization occurred simultaneously with nitriding. The rate of diffusion in a-iron has been determined from calculations based on data obtained by measuring the internal friction of samples at each of several frequencies and temperatures.' The expression for the diffusion of nitrogen in a-iron derived from these experiments is D= 1.4x10-1 e-it tudent Increasing carbon content decreases the diffusion of nitrogen in a-iron.3 Oxygen, either dissolved or combined, has been shown' to exert a marked influence on the diffusion of nitrogen from a nitriding atmosphere. D values increase rapidly with increasing amount of dissolved oxide in the metal, but diffusion is completely inhibited if preliminary oxidation has produced the slightest trace of iron oxide on the surface. Diffusion coefficients have also been calculated from permeability and solubility data,' but these values are of questionable accuracy since the boundary conditions assumed may not actually exist. Experimental Method The method selected for determining the diffusion coefficient of nitrogen in a-iron in the present investigation was the so-called fractional saturation method. This method consists of heating the specimen in an atmosphere of H2-NH8 mixtures of known composition for a predetermined time. Following this treatment, the specimen is analyzed for nitrogen; and the diffusion coefficient is calculated from a known relationship of the fractional saturation, time of diffusion, and dimensions of the specimen. This relation is based on a solution of Fick's second law and assumes that the surface of the specimen immediately reaches a given concentration which remains constant during the diffusion anneal. Tabular solutions are available4-5 and provide the relationship between fractional saturation and the quantity \/Dt /a, where D is the diffusion coefficient in cm2 per sec, t is the time of the diffusion anneal in seconds, and a, in the present experiments, is the half-thickness of the slab specimen in cm. The method is adequately discussed elsewhere.9-10 Material The material for this study consisted of 3/32 in. thick (0.24 cm) carbonyl iron plate. The major impurities in this iron are oxygen and carbon, which are readily removed by long time high temperature treatment in an atmosphere of purified hydrogen. In order to reduce the diffusion anneal time for saturation runs, some of this material was rolled to a thickness of 0.015 in. (0.038 cm) prior to the hydrogen treatment. Hydrogen treatments were carried out in a hydrogen-purified Armco iron tube heated in a global

Jan 1, 1957

By K. G. Gorling, S. J. Wallden, N. B. Lindvall

It is the policy of The Metollurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers according to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editorial Director, Rixford A. Beals; Associate Editor, James J. Burke; Assistants, L. Capria and R. K. Larkin. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Choirmon; Dennis Carney, John Chipman, J. C. Fulton, J. H. Hollomon, H. tl. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and O. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division T. B. King. Cha~rmon; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr.. and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman. F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham. Jr., Robert F. Hehe-mann, R. I. Jaffee, F. E. Jaumot, Jr., lrving R. Kramer, A. J. Leno, Horold Margolin, C. J. McHorgue, Russell A. Meussner, J. 6. Newkirk, H. W. Paxton, G. E. Pell~ssier, I. S. Servi, Alan U. Seybolt, A. J. Sholer, and Sack Wahsburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B King, F. C. Langenberg, W. O. Philbrook, and T. B. Winkler. Published bimonthly by the American Institute of Mining Metallurgical and Petroleum Engineers Inc., 29 West 39th Street, New York 18, N. Y. Telephonne pennsylvania 6-9220.Petroleum Subscription Engineers$20 per year for non-AIME members in United States and North South and Central 6-9220.SubscriptionAmerica $25 toreign; $5 for AIME members. Single copies, $4.00, iinalo copies Southfpr;ign,andCentral $5 00. The AIME 'is $25not responsible for any statement made or opinion expressed in its publications Copyright 1958 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . Registered coble address, AIME New York . . . Indexed in Engineering Index, Industrial Arts Index, ...and Chemical Abstracts . . . Application for second class mail privileges IS pending at New Yark, N. Y. Volume 212, Number 2.

Jan 1, 1959

By J. E. House, C. J. Lewis

In the solvent extraction process, also referred to as liquid-liquid extraction, the clarified uranium-pregnant sulfuric acid leach solution is contacted with an organic extractant dispersed in kerosene; the uranium enters the organic phase and associates itself with the organic extractants. Simultaneously an-ions or cations, as the case may be, leave the organic extractant phase and enter the aqueous phase. The two phases are then allowed to separate by virtue of their immiscibility. Based on the data available, a generalized procedure for the recovery of molybdenum from the sodium carbonate scrub liquor of acid leach uranium mills using secondary and tertiary amine extractants is presented, as is another generalized procedure for the recovery of molybdenum from the bleed stream of alkaline leach uranium mill circuits. Such economic appraisal as can be made at this stage of the development is also indicated. Molybdenum occurs in most uranium ores. Whether the uranium is solubilized by the acid leach route or by the alkaline leach process, some of the molybdenum present in the ore is solubilized along with the uranium. Molybdenum in uranium mill pregant solutions may cause processing difficulties, among which may be mentioned the poisoning of resins, the precipitation of organo-molybdenum complexes, or the build-up of molybdenum in recycle streams. While the uranium milling industry has been successful in applying measures to overcome the problems arising from the presence of molybdenum in the circuits, such measures nevertheless add to the cost of producing uranium yellow cake concentrate. Table I shows the analysis of typical uranium pregnant leach solutions. Uranium recovery by solvent extraction is presently practiced only in conjunction with acid leach circuits, and it may be noted that of about 16,000 tons of uranium ore daily processed by sulfuric acid leach, more than half of this tonnage follows the solvent extraction route. Uranium mills leaching ore with sodium carbonate-sodium bicarbonate solution (the so-called alkaline leach circuit) do not use solvent extraction. In this case the uranium pregnant solution is sufficiently pure to permit the direct precipitation of uranium concentrate with subsequent recycle of the alkaline leach solution. While solvent extraction procedures may be developed which are economically attractive for the alkaline leach uranium process, this has so far not been the case. The earlier uranium mill solvent extraction circuits used organo-phosphate extraction reagents, among which di-2-ethylhexyl phosphoric acid was popular. It should be borne in mind that uranium in its sulfuric acid leach solution exists in an equilibrium involving uranium in both anion and cation forms: uo + 2S0 = [uo2(so4)2] For this reason uranium may be extracted by either cation extractors or anion extractors and this is likewise true of molybdenum. However, the organo-phosphate extractants also load ferric iron which is usually present in the uranium acid leach solution. For this reason, it is necessary to reduce this solution substantially to the ferrous state ahead of solvent extraction using organo-phosphate reagents. The amines, being anion extractors, selectively reject iron and thus render the iron reduction step unnecessary. In the solvent extraction process, also referred to as liquid-liquid extraction, the clarified uranium-

Jan 1, 1961

By Ernest M. Spokes

For bituminous and lignite coals the economic picture continued to improve as it has each year since the low of 1961, with production at 480 mil- lion tons in 1964 compared with 1963's 459 million tons. The anthracite industry produced 16.3 million tons in 1964 and 18.3 million tons in 1963. The industry is looking toward a further expansion; among the new developments will be a mining wheel producing 3 million tons of lignite per year in South Dakota. It is expected that electric power generation will continue to provide the market for most of the increase in consumption, with exports second in importance in the expansion. Improvements in methods of mining and transporting coal underground and in strip mines, and the cooperation of carriers in finding ways to reduce transportation costs to distant markets, have made possible these expansions. Research continues to reduce costs of mining, transportation, steam generation of electric power and production of steam for space heating and manufacturing processes, to retain some markets and expand others. Other research seeks to expand markets by developing fuel from coal which will be more attractive than competing fuels, by reducing sulfur and other sources of air pollution. Public relations efforts of the industry are bearing fruit in a greater acceptance of coal as a modern fuel.

Jan 2, 1965

By Francis T. Freeland

In the West many precious-metal mines are worked in patches by lessees, under conditions which closely resemble those of what is called " tribute-work" in Cornwall.* The company has its own foreman or inspector, and usually employs the engineman, blacksmith, pumpman, and perhaps other general workmen. As an inducement to work on a new piece of ground, where no ore is in sight, the company may advance a " footage"

Jan 1, 1896

By C. C. Miller, A. R. Belyea, C. H. Herty, E. B. Burkart

The removal of sulfur from steel has been studied by many investigators, but the quantitative relationships between the factors involved have not been determined. This is undoubtedly due to the number of variables encountered in practice, an attempt to study any one reaction or relation being affected by other reactions the relative importance of which cannot be estimated. The factors that affect the extent of removal of sulfur in the basic open-hearth process are generally considered to be: 1. Basicity of the slag: (a) Iron oxides in the slag; (b) carbon in the metal or carbide in the slag; (c) temperature. These factors affect the reactions: FeS + CaO = CaS + FeO FeS + CaO + C = CaS + CO + Fe. 2. Amount of sulfur in the gas. 3. Amount of manganese in the metal. The factors which affect the rate of removal of sulfur include, in addition to these: 4. Fluidity of the slag: (a) Normal changes in fluidity with temperature; (b) changes in fluidity because of the addition of special reagents such as fluorspar. 5. Agitation of the bath. Within the past two years, two papers have been presented dealing with the influence of sulfur in the gas on slag and metal. Nead' has shown that if a gas high in sulfur be used for heating, the metal and slag will absorb sulfur. Whitely2 concluded from his experiments that if a

Jan 1, 1925

By V. J. Sikora, W. J. McGuire

Several years ago, we used an electric analogue computer to study the effect of vertical fractures on the productivity of wells in expanding fluid-drive reservoirs. The results of this work were used both as a guide to research and as a basis for the design of actual fracturing operations. In 1958, Dyes, Kemp and Caudle' published portions of the data from this study. The results were released in 1959 to service companies for use in fracturing guides. The purpose of this note is to discuss the experimental conditions and assumptions which were made to derive the information which is already partially a matter of public record. ASSUMPTIONS This study applies to fractures which extend in a vertical plane symmetrically from the well. For simplicity, we chose to study the case of a well in a square drainage area with its fractures extending toward two of its nearest neighbors. We have assumed no migration of fluid across the boundary of this area. The quadrant shown in Fig. 1 models this system. We made the usual assumptions that the reservoir is homogeneous and isotropic, that the fluid is homogeneous and that production is effected by fluid-expansion drive. We also assumed that the fracture extends from top to bottom of the reservoir. Of more practical interest is our assumption that the fracture does not change the size of the drainage area. This premise is appropriate if all the wells in the reservoir are fractured in the same way. But where a single well is fractured, its drainage area may be enlarged at the expense of its neighbors. This could be of economic importance. The assumption that the fracture will not extend beyond the established drainage area of the well also limits the application of the results. Such long frac- tures will yield benefits in excess of those predicted here. When we assume homogeneity, we disregard the frequently observed zone of damage in the vicinity of the well. Where damage is severe, the benefits resulting from by-passing it will far exceed those predicted by this study. All comparisons were made of systems producing in the semi-steady state. By this we mean that equal volumes contributed equally to flow (pressure was dropping at a uniform rate throughout the system) when the rate of flow was observed. EXPERIMENTAL SET-UP We used the pool unit of an electric analyzer' in this study. The squase drainage system of a well was rep-

By John V. Beall

Since the U. S. Metals Refining Co. works was established, around the turn of the century, near the town which is now called Carteret, N. J., it has grown to be a major producer of refined copper and the main source of that special brand known as "oxygen-free high-conductivity copper." Owing to the complex metallurgical problems arising from handling a variety of raw materials such as copper concentrate from Matahambre, Cuba, copper and brass scrap from the New York area, and domestic blister copper, the organization is geared from top management down through its 2000 employes to maintain a high degree of flexibility in plant operation. The Company is a subsidiary of The American Metal Co. Charges for the smelter furnaces, one reverberatory furnace and one blast furnace, are made up in. bedding bins so that they may be tailored to the production of a constant grade of blister copper. The reverberatory furnace smelts the .sulphide charge, which may be a blend of ten different materials but principally the Cuban concentrate, and the matte from the process is poured into a converter. This reverberatory is 80 by 20 ft, silica lined with a slag bottom, fired by pulverized coal, and continuously side-charged from the top by bottom-dump cars which keep the side walls covered. It produces a 40 to 50 per cent copper matte. The fuel-charge ratio is 4.35 tons of solid charge per ton of coal. The furnace has a capacity of 10,000 tons of charge per month and produces from 5000 to 6000 tons of slag per month which must be disposed of. About 5000 tons of converter slag is produced monthly and returned molten to the reverberatory furnace. The converter gases go through a spray chamber to a Cottrell precipitator and thence to the flue system. Smoke from the

Jan 1, 1948

By M. N. Shetty

LARGE copper whiskers (-100 p) of 11111 orientation were tested in a floor-model Instron testing machine, at liquid nitrogen temperature. (Testing methods will appear elsewhere.) Whiskers deformed by twinning after some initial deformation. A load-elongation curve at the onset of twinning is reproduced in Fig. 1. Twinning was confirmed by taking a back-reflection Laue picture, using a slit colli-mator, which showed distinct splitting of reflections. The tensile stress reached just before twinning is about 1.4 x 107 g per sq cm (-7.0 x106 g per sq cm—resolved shear stress) which drops to 1.2 x107 g per sq cm (-6 x 106 g per sq cm—resolved). This twinning stress is about five to ten times larger than the value for bulk single crystals of copper deformed at 77°K (-106 g per sq cm—resolved). Twinning models based on Cottrell-Bilby's pole mechanism are discussed in detail by Venables.' In the present work a mechanism based on the idea of failure of a Lomer-Cottrell barrier by recombination will be proposed. An L-C barrier may fail either by recombination or by dissociation.3 Fig. 2 provides the necessary information. It shows that the stress necessary to break such a barrier is about 1.8 x 107 g per sq cm by recombination and 4 x 107 g per sq cm by dissociation at 77°K. The twinning stress reached by whiskers is comparable to the stress level required for failure of an L-C barrier by recombination. (Stroh himself points out that his calculations should not be taken too literally.) We consider a segment of the L-C dislocation which has recombined (AB in Fig. 3) over a length to form the total dislocation which then glides in the

Jan 1, 1965

By L. M. Kaas

Production planning techniques, particularly a production scheduling model are proposed for use in taconite mining in Minnesota. Applications of the scheduling model, on a two-year mine plan, which evaluates the equipment involved, are detailed. Data and tables are included. INTRODUCTION Fifty years ago Walter Swart, a mining engineer investigating the Minnesota taconites for the Jackling interests, made this report: "There is no doubt in my mind that this taconite mining is a game worth playing and that it can be played to a successful finish. It seems now only a question of men, money, methods and details."' The prosperous industry envisioned by Swart and other taconite pioneers is today a reality. Its growth has been spurred by technological advances in mining and beneficiation, depletion of natural ore reserves, and improvement of the economic climate. However, the massive problems that were solved to make this development possible are only a foreshadowing of the questions of "men, money, methods and details" that will be encountered in the future. The increasing demands for higher quality taconite pellets have already forced producers to examine better methods of quality control for their operations. THE NEED FOR PRODUCTION SCHEDULING The maintenance of fairly constant crude ore characteristics is of major importance to mill quality control. Through careful mixing of ore from storage bins, the concentrator staff can partially reduce the deviations of the feed analysis from the analysis desired. However, the limited effectiveness of bin mixing systems has caused some mining companies to utilize large capacity blending piles to reduce grade variations. Although the analysis of material being reclaimed from such a pile is relatively uniform, raw materials still must be scheduled from the mine into the pile in such a manner that the average analysis of all material is close to the feed analysis prescribed by the mill. PRODUCTION SCHEDULING MODEL Minnesota taconite mining companies have used three analyses to estimate how a certain ore will react to concentration. These factors are the crude magnetic iron content of the ore, the iron content of the plant concentrate produced from the ore at a standard grind, and the grindability index of the ore. The actual laboratory tests used to determine these factors have been described by Apuli.2 These data are obtained from analysis of diamond drill cores, and are the established criteria used by mine planning engineers to formulate taconite production schedules. Variations in the grade of mine output should be controlled by any production scheduling system. However, to be truly practical, production scheduling methods must also consider many of the less tangible variables that affect mine operation. These include pit layout, available equipment, and ownership of ore leases. The number and scope of the variables inherent in this type of mine planning suggested that a computer simulation could be used to solve the problem. The preparation of information for use with a computer simulation program was the initial phase of this project. Meaningful data was developed from logs of diamond drill cores. Analyses were related to their respective areas of influence by means of mine maps, Fig. 1. The three assay variables and tonnages for each area were punched on cards. In addition to these values, a location code number was punched in the first eight columns of the cards. This code is explained as follows: Column 1 Bench number Column 2 Quadrant location as determined by mine reference lines Columns 3-5 East-west coordinate Columns 6-8 North-south coordinate The heart of any simulation techniques is a well engineered mathematical model. To develop a model for taconite production scheduling, the relationship between the three assay variables had to be established. Because changes in each analysis factor affect the mill circuits in different manners, a weighting system was used to determine the relative im-

Jan 1, 1967

By ALBERT F. J. BOARDEAUX

(Canal Zone Meeting, November. 191(j.) I. GENERAL INTRODUCTION. 1. Historical. ALLUVIAL gold was first discovered in Guiana in 1852, in the sands of the Arataye river; by Paulino, a Brazilian convict. During the following years, gold was found also in the rivers Orapu, Cirubé, etc. In 1873 the famous placers of the Sinnamary system were opened: Saint-Elie, Dieu-Merci, Adieu-Tat, and Couriége. This group of mines has produced nearly $10,000,000, according to official records, not including the gold that escaped the taxes. The discoverer was a mulatto named Vitalo. Except in a few rich spots, the gold was rather evenly distributed along the creeks. In one instance, gold was found in the red dirt from the slope of a hill, which, after transport to the creek, gave an amount of 150 kilograms. The placers of the Mana system, Enfin, Elysée, Pas-Trop-Tot, date from 1878, and their production has been about $5,000,000. In 1888, the Awa placers, along the boundary between the French and Dutch Guianas, on the Maroni and its tributaries, were discovered. They have yielded $12,000,000. The only industrial company,, the Dutch Guiana French Mining Co., produced in 15 years about 2,500 kg. of gold, worth $1,500,000. From 1893 dates the famous Carsewene discovery, in territory then in dispute between France and Brazil. A settlement was made recently in favor of Brazil, by arbitration of the Switzerland State Council. Carsewene is said to have pro-duced about $18,000,000 in six years (1894-1900), but not even one-fourth of the production went through French Guiana and

Nov 1, 1910

By D. J. Coolidge, H. L. Sheakley

THIS paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- [ ] duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is commonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. [ ] The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. , I). Above the sand rock an overburden of Joachim limestone appears, which, thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes, where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. PROPERTIES OT THE ST. PETER SAND From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1942

By K. W. John, L. Mueller

The rock mechanics approach to stability problems of steep rock slopes dealt with in this article has particular reference to the concept and methods of analysis developed by the Salzburg, Austria, school of rock mechanics. These theories are based on the principal postulate of the anistropy of the technological properties of in-situ rock masses. The present approach, which is more in line with geological engineering concepts, differs distinctively from the soil mechanics and engineering geological concepts commonly practiced in the United States. PRINCIPAL ENGINEERING APPROACH TO GEOTECHNICAL PROBLEMS AVAILABLE ENGINEERING CONCEPTS At the present time two different concepts are available for engineering analysis of underground structures and foundations in different earth material: soil mechanics and rock mechanics. Of these two branches, soil mechanics is, after 40 years of initially revolutionary and more recently evolutionary development, well established. Its principal concept of replacing in-situ soils or rock masses by perfectly homogeneous substitues has resulted in many practicable methods of analysis which, if applied with judgement, have resulted in successful applications throughout the world. Conversely, rock mechanics is still in the early stages of revolutionary development. Few, if any, standard concepts or methods of analysis have been established. Opinions vary widely. At present the professional background of an investigator very often determines the engineering concept to be applied to a particular problem, rather than its actual requirements if considered objectively. This paper stresses the rock mechanics or geological engineering point of view advocated by the Salzburg group. A review of the soil mechanics concepts is considered beyond the scope of this paper. THE "SALZBURG APPROACH" TO ROCK MECHANICS The rock mechanics concept as outlined here was initiated by Stini, based upon work by sander.1 Since

Jan 1, 1963

By P. van Meurs, C. van der Poel

From observations of the linear displacement of oil by water from a porous medium as visualized in transparent models, new insight into the mechanism of vircous fingering, as occurring in the case of unfavorable oil-water viscosity ratios, has been obtained. A mathematical description of the observed phenomena leads to formulas. expressing both oil production and pressure drop across the formation as a func-tion of cumulative water injection with the oil-water viscosity ratio as a parameter. Theoretical results are compared with those obtained from scaled laboratory experiments in sand-filled rubes in which water was injected at the one end and production was obtained from the other end. In the second part of the paper the same principles are used to calculate a more realistic production scheme in which production of oil and water is obtained from wells regularly distributed over the field. Results show satisfactory agreement with production data of an actual oil field. Application of the theory is extremely simple as only a limited number of readily available parameters have to be known and results are presented in an analytical form. INTRODUCTION When oil is displaced from a porous medium by water having a viscosity lower than the oil. the oil-water interface is essentially unstable and has the tendency to break up into what are called "fingers" or "streamers". This Viscous fingering has been noted before by Engelberts and Klinkenberg' and has recently been demonstrated in transparent models by van Meurs-. It is highly questionable whether it is at all possible to perform relative permeability measurements In the laboratory reproducing the same distribution of water and oil in the cores as Present in practice. Therefore, we based our descriptive theory on an idealized model which was "tailored" to the fingering mechanism as observed in transparent models under scaled conditions. This approach was the more attractive, as a highly simplified model had already yielded an adequate description of the process. Though we are aware our theoretical approach can be extended in several ways, it is given here in its simplest form to explain the fundamental principles and to avoid complicated formulas. SIMPLEST CASE OF A LINEAR DRIVE Observations and Theoretical Model In Fig. 1 a series of photographs shows how water penetrates into a formation saturated with an oil which is considerably more viscous than the water. The technique for obtaining these photographs, using transparent models, has already been described?. The fingers can be clearly observed and are seen to be mainly parallel to the flow direction. Note that the contours of these fingers are not smooth but show protrusions of water enclosing oil pockets.

Large deposits of manganiferous iron ores, representing several million tons of metallic manganese, occur in the United States. The Minnesota deposits of such ore are of outstanding importance because of their size, state of development, ease of mining and proximity to the Great Lakes, which permits water transportation to steel centers. In view of the fact that our steel industry requires large quantities of manganese, for which no satisfactory substitute has been found, and because our reserves of ferro-grade ore are comparatively small, the development of methods that will make our large deposits of manganiferous iron ores available as a source of ferromanganese is an important problem. Realizing the importance of this problem, some years ago the North Central Station of the U. S. Bureau of Mines and the Minnesota School of Mines Experiment Station undertook jointly the development of methods for recovering the .manganese content of manganiferous iron ores in a form suitable for the production of ferromanganese, the 80 per cent. alloy indispensable in producing steel. Two types of manganiferous iron ores have been described in previous reports.' The brown ores are higher in iron and lower in manganese than the black ores; the black ores are more siliceous but contain less phosphorus. The utilization of the iron content of the brown ores in the production of steel appears to furnish the best basis for their treatment. The method of attack has been to work out modifications in iron and steel practice so as to recover manganese in the form of slag comparable to ferro-grade ores. The greater part of the experimental work has been conducted with a 6-ton blast furnace and a 1/2-ton basic open hearth. This paper is devoted mainly to open-hearth tests in which high-phosphorus spiegel

Jan 1, 1930

By Samuel Hoyt

SOME of the more important properties of finished materials are strength, ductility, toughness, resistance to alternating and repeated stresses, etc: Of these, the property that appears to have received the least consideration, at least in this country, is toughness, which is clue, possibly, to our regarding toughness as a qualitative property or, at any rate, as one that, parallels ductility. This arises out of our greater experience with the simple carbon steels in the rolled or forged (non-heat-treated) condition which, qualitatively, are tough if ductile and are not tough if brittle. In this way we have erroneously become, accustomed to judging the toughness of a material from its behavior in the tensile or similar test. The point of view presented in the present paper is that toughness, like hardness or tensile strength, should be regarded as an independent property and of sufficient importance to require, in so far as that may be possible, quantitative determinations. If such be true, it becomes at once necessary to devise experimental means for measuring, or valuating toughness, and the notched-bar impact test (the Charpy test) is advanced as the most logical test that has so far been developed for this purpose. It is further advanced, with particular emphasis, that we have two kinds of toughness to deal with and, accordingly, they will be dealt with independently. CLASSIFICATION OF MATERIALS ACCORDING TO TOUGHNESS Toughness has been defined somewhat as follows: Tough materials are those that offer considerable resistance to permanent deformation but which, once such resistance has been overcome, may' be deformed plastically, but only by the expenditure of considerable energy. In other words; tough materials may be deformed plastically but they absorb a considerable amount of work in the process. This kind of toughness may be called "static" toughness when the rate of loading is reasonably slow or "dynamic" toughness when the rate of loading is

Jan 2, 1919

By J. W. MacDonald

Review of equipment, performance, and shaft design plans including head-frames for sinking and forms for lining are given. Also included are comparative data for shafts of 11 x20 ft and 193/4 x 30 ft with 756 and 666-ft depths, respectively. Advantage from curtain wall installation with "slip forms" which warrant consideration for normal lining are outlined. A preliminary review is also made of "chemical grouting" to stop water inflow leakage with Halliburton equipment and service. Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review. These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work. TEST DRILLING Core test holes were drilled within each of the two shaft locations. Four additional cable tool holes were drilled on a radius of 700 ft from the shaft bottom to determine the coal seam elevations and govern the underground layout plans for each shaft. A graphic log of the hoist shaft test drillhole is shown by Fig. 1. A very soft sandstone was found at a depth of 16 ft. Cored recovery of the sandstone proved much weaker than the overlying compacted sand secured with coring facilities for soil recovery. Gradation from the very soft sandstone to fairly hard material occurred with the next 14 ft, extending to a depth of 30 ft. The weak character within the upper portion entailed need of adequate protection when sinking as described later. A part of the sandstone provided sufficient porosity and permeability to warrant further investigation. Adjacent cable tool drilling for temporary water supply disclosed inflow was limited to 2 gpm with a depth of 40 ft. It was increased to 12 gpm during the next 50 ft of drilling and occasioned subsequent precaution when sinking. General arrangement of facilities for sinking the hoist shaft is shown by Fig. 2. An available steel frame building was used to accommodate the hoist, compressor, shop, and shower or change room. The stiff leg derrick with 90-ft length of boom permitted removal of forms from the wood shop to the storage area or delivery within the shaft. Reinforcing steel and other needs were similarly handled, in addition to headframe erection. The headframe was placed over one end of the shaft to enable passage of forms for lining through the adjacent half next to the stiff leg derrick. The steel headframe as shown by Fig. 3 was fabricated locally. Side anchored cables from the

Jan 1, 1961

Jan 1, 1961

By Waldemar Lindgren

THE following pages present data accepted by many geochemists and geologists regarding the succession of minerals and the temperatures of formation in ore deposits affiliated with igneous rocks. They also present the individual views of the author on the composition of the solutions that were active and on the mode of deposition. He does not regard these views as speculations or hypotheses but as forming a well motivated and consistent theory. It is not certain, however, that all investigators will subscribe to them.

Jan 1, 1936

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe's love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd's register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943