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By Paul M. Tyler

DOES mining pay? Inasmuch as the whining of minerals from Nature is one of the world's principal sources of new wealth, this question is of general economic interest but it is obviously of even more vital concern to investors and those engaged in mining. In a previous article on "Wage Costs in the Mineral Industries,' published in the November issue, I attempted to show that wages paid workers on the job accounted for, roughly, 50 per cent of the mine dollar. Salaries normally range over 5 per cent - lower for large metal mines but higher in stone quarries and minor nonmetallic min. in, industries. Purchases of supplies, materials. fuel, and power generally aggregate within the range of 15 to 25 per cent of total receipts, with the average well under 20 per cent. The total of all such specified expenditures which may he loosely described as

Jan 1, 1934

Jan 2, 1951

By G. Ansel, J. O. Betteron

THE PURPOSE OF THIS PAPER is to give a brief picture of present day magnesium rolling practice, to elaborate on laboratory and development rolling experiments; and finally, to discuss the possible Future rolling of magnesium. The present production practice is so varied between various mills that it can only he concluded that no single producer is now using a process that is outstandingly superior to others. In view of this, only the general features of present day production practice have been presented and attention is focussed on the results of laboratory find development rolling of magnesium-base alloys as indications of the Future trend of magnesium rolling. MAGNESIUM ROLLING LITERATURE The literature relating to magnesium rolling is divided into three groups: the deformation mechanisms of the hexagonal magnesium crystals, the metallurgical aspects and laboratory type experiments in rolling, and finally, the articles on production rolling methods. This literature was reviewed and is summarized below. In the first group of references, the existence of basal slip in magnesium single crystals was shown by Schiebold and Siebel1 and of {102} twinning by Mathewson and Phillips2, Schmid3 predicted and partially established {101} slip at hot working temperatures. Bakarian and Mathewson4 confirmed the above and eliminated {101} twinning as a probable deformation mechan-

Jan 1, 1948

By A. STEPHENSON

EXPERIMENTAL work conducted at the Petroleum Engineering Laboratory of the University of California by L. C. Uren, J. Domercq, Jr., and J. Mejia has shown that small diameter wells offer tremendous resistance to the flow of fluids in their immediate vicinity. This resistance is due in part to the constriction of the area through which the fluids must pass as they approach the wall of the well, but is also accentuated by the increased volume which results from gas expansion. The latter in turn is a function of the deduction in pressure, the fundamental cause of fluid movement. If the diameter of the bore is enlarged several diameters, the capacity of the well, or the volume of fluid passing per unit drop in pressure per unit of time, is greatly increased without necessitating such high fluid velocities. The fundamental features which should be taken into consideration in the design of casing joints were stressed by J. B. Graham and E. E. Smith. These involved such points as correct thread design, high efficiency, and small diameter, together with the insurance that leakage will absolutely be prevented. The practical features of such design were ably discussed by engineers from leading steel manufacturers.

Jan 1, 1935

Jan 6, 1951

[Officers and Committees of the Society of Petroleum Engineers 1 Officers and Staff of the AIME 2 Officers of AIME Sections Predominantly Petroleum in Membership 3 Society of Petroleum Engineers By-Laws 5 Alphabetical List of Members 9 Geographical List of Members 110 List of Members by Companies 127 Advertisers' Index 137]

Jan 1, 1961

Jan 7, 1976

Jan 3, 1976

Jan 1, 1887

By M. Duclos, A. Sawatzky

A simple model has been developed which describes the steady-state solute distribution in Ti-H type systems above the eutectoid temperature in the presence of a temperature gradient. The solute distribution is dependent on the shape of the phase boundaries. An interesting result, and one that is not observed at steady state in thermal diffusion below the eutectoid temperature, is the existence of a two-phase region. The heat of transport for hydrogen in a titanium, Q*a, over the temperature range 275" to 650.C is determined to be 4500 * 230 cal per mole. The heat of transport for hydrogen in B titanium, QB* over the temperature range 320" to 590.C is found to be 630 ± 200 cal per mole. It is also shown that thermal diffusion provides a method by which phase bounduries above the eutectoid may be determined in Ti-H type systems. IN modern technology materials are being used at constantly increasing temperatures under greater temperature gradients. Thus atomic migration in metal alloys due to a temperature gradient (thermal diffusion) may in some cases occur to an observable extent. The thermal diffusion of hydrogen in zirconium has in recent years received considerable attention1-' because of the use of zirconium alloys in nuclear power reactors. The thermal diffusion kinetics below the eutectoid (547°C) are fairly well understood. At steady state the solid solution, a, and hydride, 6, phases are completely separated with the hydride precipitating at the lower temperatures. No experimental work has been carried out in the a + B region although Droege4 suggested that a complete separation of the two phases, as observed at temperatures below the eutectoid, might not always occur. In the present investigation a simple model has been used to determine the steady-state solute distribution under a temperature gradient in Zr-H type systems heated above the eutectoid temperature. The solute distribution is shown to be dependent on the shape of the phase boundaries in the constitutional diagrams and several typical cases are discussed. The model has been applied to Ti-H. This system was chosen in preference to Zr-H because of its much lower eutectoid temperature (-300°C as compared with 547.C), thereby reducing experimental errors due to oxidation and hydriding. The heats of transport for hydrogen in the a and B phases of titanium also have been determined since they were required to compare the proposed thermal diffusion model with experiment. THEORY In the presence of a temperature gradient the atomic flux in a single-phase region of a two-com-ponent system of which the atoms of only one component are diffusing is given by:' J = - U\dx + RT3 dx) which can be written as: j-D(dn/dt +Q*n/RT2)dt/dx [11 J - -D\dT + RT2)dx [1] where D = diffusion coefficient, n = solute concentration, T = absolute temperature, R = gas constant, dT/dx = temperature gradient, and Q* = heat of transport. At steady state (J = 0) Eq. [I] leads to the solute distribution: n = noexp Q*/RT where no = a constant depending on total solute content. The heat of transport Q* can be experimentally determined from the steady-state distribution. In the present paper we shall determine the solute distribution in systems having the constitutional diagram exemplified by Ti-H shown in Fig. l.' As shown, N,(T) and NB(T) are the equilibrium solute concentrations in the a and 0 phases at temperature T. Lines AA' and CC' define the region of interest to us. The following assumptions are made: 1) Steady-state conditions prevail. 2) In a single-phase region all points on an isotherm have the same thermodynamic potential so that the composition over an isotherm is uniform. If a two-phase region exists, thermodynamic equilibrium is found only at phase interfaces. However, we assume the component of the concentration gradient along an isotherm to be small so that the composition in each phase is approximately the same as at the interface and is given by the constitutional diagram, Fig. 1. 3) There is appreciable diffusion of only one component. 4) We shall consider only the case where Qa*, QB*, and Qg*, the heats of transport for solute diffusion in the a, B, and 6 phases, respectively, are positive. This has been observed for the thermal diffusion of hydrogen in zirconium3 and titanium.10 We will show that the steady-state solute distribution above the eutectoid is primarily determined by the heats of transport and the temperature dependence of Na(T) and Np(T). It may be quite different from the steady-state distribution below the eutectoid. For example, we will see that, under certain conditions,

Jan 1, 1970

By K. E. Nelson

The effect of thorium and zinc variations on the strength and 100-hr creep characteristics of Mg-Th-Zn-Zr alloys was investigated. Optimum resistance to creep at 650° and 700°F are attainable within a certain range of thorium and zinc contents. This range does not conform to that which develops maximum tensile properties. RAPID advances have been made during the last few years in the development of magnesium alloys for elevated temperature applications demanding high resistance to creep. The beneficial effect of rare-earth metals on the creep resistance of magnesium alloys has been emphasized by a number of publications1-13 and such alloys are now in commercial production. The use of thorium as an alloying ingredient in magnesium was mentioned by McDonald and also in two Alien Property Custodian patent applications.10,17 The initial observation of Sauerwald that thorium contributes still higher creep resistance to magnesium than is attainable with rare-earth metals has recently been substantiated.'" " In fact, it has been demonstrated that the useful temperature range of magnesium alloys is appreciably extended by the use of thorium. In all cases, it was observed that zirconium must be included in the alloys in order to render them fine grained and more readily castable. Several recent publications:2-27 indicate that a still further improvement in creep resistance and a further extension of the useful temperature range can be realized by the addition of zinc to alloys. The primary purpose of this paper is to present the results of a comprehensive study of the effect of zinc on the strength and creep characteristics of Mg-Th-Zr alloys. Compositions covering the range of thorium content from M to 6 pct and zinc content from 0 to 5 pct have been investigated. The creep characteristics at 650" and 700°F reported in this paper are based on results of tests of 100-hr duration. It is appreciated that creep tests of 100-hr duration might not yield adequate data for design purposes for parts with much longer expected life. However, for the purposes of the present discussion, it is felt that the combination of stresses and temperatures used in the 100-hr creep tests have yielded a clear representation of the compositional variation of creep resistance at the temperatures investigated. Creep tests of 1000-hr duration are now in progress on a few of the most promising alloys. Preparation and Testing of Alloys The alloys studied in this intensive investigation were prepared in 25 lb capacity mild steel crucibles. The thorium, zinc, and zirconium were alloyed and poured as described in earlier publications The thorium was introduced into the melt in the form of a Mg-Th hardener," the zinc added in the metallic form, and the zirconium alloyed in the form of the commercial hardener containing magnesium and 30 to 50 pct Zr.10, 26 Fluxing practices for melting and refining were the same as for magnesium-rare-earth metal-zirconium alloys. The melts were sampled for analytical determinations and poured into separately cast 1/2 in. diameter standard tensile bars. The test bars were given a precipitation treatment of 16 hr at 600°F in laboratory furnaces. It has been shown by other tests that a high temperature solution treatment followed by an aging treatment is unnecessary for the development of optimum properties in Mg-Th-Zn-Zr alloys. The selection of 600°F as the aging temperature was based on an attempt to achieve metallurgical stability without coalescence of the undissolved phases and the attendant loss in strength. The thorium, zinc, and zirconium contents of each melt were determined chemically. The zirconium contents are reported in two parts, "soluble" and "insoluble," referring, respectively, to the portions present in the alloy which are soluble and insoluble in dilute HCl acid. Distinction is being made between these two components of the zirconium content in the alloys because it has been found that only that portion of the zirconium content which is soluble in dilute inorganic acids affects the structure and properties of the alloys. The usual impurities consisting of copper, iron, manganese, and nickel were determined spectroscopically. The analysis for each melt is listed in Table I. A description of the methods of tension and creep testing has been detailed in earlier papers. The tests were performed with the cast skin re-

Jan 1, 1954

By Yingchang Tsenshan Wang

UUIN L&SS 1» Paqb I. Introduction........................................................658 1. Subject and Scope...............................................658 2. Acknowledgments...............................................659 3. Review of Previous Work........................................659 Field Data...................................................659 Experiment.a1 Data............................................662 4. Plan of Present Investigation.....................................662 Method of General Procedure...................................663 I1. Experimental Work..................................................663 A. The Solution of Sphalerite..............................:........663 1. The Solvent Effect of Iron Sulphates upon Sphalerite...........663 2. The Solubility of Sphalerite in Salt Solutions of Silver, Copper and Lead...............................................668 B. Formation of Zinc Carbonates....................................674 3. The Reactions of Carbonates and Bicarbonates With Solutions of Zinc Salts............................................674 4. The Reaction of Zinc.Sulphate Solution With Limestones.......684 C. Peculiar Conditions Affectitig the Formation of Zinc Silicate (calamine) and Zinc Carbonate (smithsonite)..........................686 5a. The Effect of Carbon Dioxide Upon the Basic Silicate and the Carbonates of Zinc in Water, and Its Bearing Upon the Conditions of Theii Precipitation..............................686 5b. The Reactions of Solutions of Soluble Silicate With calamine and Smithsonite in Solution in Presence of Carbon Dioxide..689 6. The Reactions of a Mixture of Hydroxide and Silicate of Sodium with a Dilute Solution of Zinc Sulphate...................691 D. High-Temperature Methods.....................................692 7a. The Influence of Temperature on the Formation of Calamine..692 7b. Possible Effect of Heat on Calamine and Srnithsonite.........697 E. Summary of the Experimental Work..............................698 III. Petrographic Work....................................................700 1. The Occurrence of Sphalerite in Limestones or in Cherts............701 Summary of the Blende in Limestones and in Cherts.............7432 2. The Partially Altered Sphalerite and the Oxidation Products........702 a. Smithsonite with Blende....................................702 b. Calamine with Blende......................................703 c. Smithsonite and Calamine..................................703 d. Summary on the Partially Altered Sphalerite and Its Oxidation Products..............................................704 IV. Concl~~siom ........................................................-705 V. Microphotographs and Photographs with Their Explanations.............705

Jan 1, 1916

By D. J. Jr. McAdam

RESULTS of a general survey of corrosion-fatigue phenomena at the Naval Engineering Experiment Station were presented in five previous papers.1-5 In these papers references were given to the work of Haigh in 1917.6 The five papers mentioned gave a general survey of the behavior of metals when tested to failure under simultaneous corrosion and cyclic stress. As a result of this survey the fourth paper gave a tentative analysis of the corrosion-fatigue process. According to this analysis, if the initial stress is below the endurance limit but above the corrosion-fatigue limit, the corrosion-fatigue process is divided into two periods. The first period is the formation of pits. As the initial stress is below the endurance limit, the pitting is assumed to be due to corrosion, not to fatigue. The corrosion pitting, however, is not the ordinary pitting of stressless corrosion, but is an accelerated pitting due to the effect of the cyclic stress on the corrosion. As the pit progresses, both the actual stress and the effective solution pressure increase. The increase of actual stress is due to increasing stress concentration at the bottoms of the pits. The increase of effective solution pressure is due to the increase of actual stress. The mutual intensification of stress and solution pressure continues until the actual stress at the bottoms of the pits surpasses the endurance limit. The second period of corrosion-fatigue then begins. In this period the process is merely fatigue accelerated by the corrosion. The cracks advance at a continually accelerated rate until the specimen breaks.

Jan 1, 1930

By H. LeChatelier, B. Bogitch

Page Introduction........................... 134 Methods of Investigation....................... 135 The Tridymite Network...................... 137 Independent Variables....................... 146 Manufacturing Operations..................... 153 Introduction Silica brick are indispensable in the manufacture of steel because they alone are able to withstand the high temperature of regenerative furnaces. All attempts to replace silica brick by other refractory materials for this purpose have failed, but the reason for this failure has remained obscure; we shall give an explanation later in this paper. Before the war, silica brick employed in France came principally from abroad, for which reason, since the beginning of hostilities, certain French steel works have been seriously handicapped. Our attention was first directed to the question by M. Bied, Engineer of the Teil Works. With him, we began certain investigations, at first using our laboratory and the furnaces of neighboring steel works. The larger part of our experiments, however, have been made in the laboratory of the Faculty of Sciences at the Sorbonne. For the heating of our samples, we are deeply obliged to MM. Charpy, Yeatmann and Guerineau. In undertaking these studies, our first aim has been to render assistance to French industry, by indicating, as precisely as possible, the necessary conditions for the manufacture of high-grade brick; but at the same time me have

Jan 1, 1919

By T. Sterry Hunt

Coal was mined to a small extent near Tuscaloosa, in Alabama, and even carried by boats to Mobile, half a century since. Professor Porter, and later, Professor R. T. Brumby, occupied themselves with the geology of the region, and it attracted the attention of Sir Charles Lyell, who visited the region. It is, however, to the two reports of Professor Tuomey, geologist to the State, published in 1850 and 1858, that we owe our first clear notions of the geology of the Alabama coal-fields. His work has, since 1873, been continued by Professor Eugene A. Smith, of the University of Alabama, whose valuable reports, extending and completing the work of his predecessor, are indispensable guides to the geological inquirer in this region. Mention should also be made of the investigations of Mr. R. P. Roth well, who, after three years of studies in parts of the Alabama coal-fields, read before the American Institute of Mining Engineers, in October, 1873," a brief but important paper calling attention to the great deposits of coal and iron-ore found therein, and to their economic importance. Having myself, during the past year, had an opportunity of visiting parts of this region, I have thought that it might be well to bring before the Institute some facts and considerations as to its geological and geographical characteristics, and the value of its mineral resources. It is well known that the great Appalachian coal-basin, stretching southwestward through western Tennessee and the northwestern corner of Georgia, terminates in northern Alabama in what is called the Warrior coal-field, which there covers an area of about 5000 square miles. Lying along the southeast border of this, but

Jan 1, 1883

By AIME

DURING the Revolutionary War an iron mining industry was born in the Adirondack region of New York State. New York State ores provided the iron from which were forged the links of the chain that, strung across the Hudson River, successfully kept British vessels from ascending. The industry flourished for a while and then became dormant. For the successful prosecution of World War II, the magnetite mines were revived and given considerable aid in the form of government financial support. The complete story appeared in a special issue Of MINING AND METALLURGY published in November 1943. Now, almost four years later, it is interesting to see that these "war babies" were not really such but are well-established enterprises with a bright future. A ten-day trip through the Adirondack region and to St. Lawrence County dispelled all thoughts that mining in northern New York State is a transitory industry. In addition to substan-

Jan 1, 1947

By R. H. Hadfield

Professor ArnolD, of the Sheffield Technical School, who has done so much excellent work in metallurgical research, recently produced, with the aid of aluminum, a sound ingot and bar from the purest known Swedish brand containing 99.8 per cent. of pure iron. Table 1. shows the physical quantities of this metal. TABLE I.— Tests of a Sample of Almost Pure Iron Prepared by Professor Arnold from D. v Ewedish Bar, Containing Before Fusion 0.04 Per Cent. of Carbon. I. II.+ III. Series mark,.. 136 1.371F ...... C, 0.07 0.07 Si, 0.04 0.04 8, 0.02 0.03 ...... Analysis, per cent,. .. P, 0.02 0.015 ...... Mn, 0.06 0.07 Al, 003 ............ Fe, 99.76 99.81 ...... Specific gravity,........... 7.863 ...... Original diameter, inches,. .. 0.564 0.798 0.798 Original area, square inches,. . 0.25 0.50 0.50 Limit of elasticity, tons per square inch,...... 18. 3.8 Breaking-load, tons per square inch,. 21. 23. 14.75 Total elongation, per cent., measured on 2 in.,...... 50. 49.25 61. Total reduction of area, per cent.,. 80. 69.60 61.20 Extension at permanent set, per cent.,...... 0.007 ...... silky and Appearance of fracture,. .. . silky i granular in parts.

Jan 1, 1894

By George W. Bain

Methods of mining building stone of any sort are planned to produce as few fractures as possible, and present a strong contrast to methods of mining metallic ores, which must be crushed eventually and have fractures produced in as great profusion as possible. Shocks transmitted to a stone invariably make it more porous and more permeable and reduce its effective life, therefore methods of mining building stone involve as This building illustrates the fine detail of workmanship, unprotected sharp corners and thin edges, and tall narrow columns characteristic of marble structures. These features require exceedingly coherent stone, and preservation of these features for decades or centuries demands many special quarrying precautions to keep absorption to 0.14 per cent or less, a detail not essential to stone for coarser architectural types. few shocks as possible. This is singularly true for marble because marble structures are intended to have long life, greater delicacy of line, more gracefulness and fineness of sculpture than those made from any other structural material (Fig. 1). So that delicate lines may remain in almost perfect preservation for decades, or even centuries, it is important

Jan 1, 1938

By George W. Bain

Methods of mining building stone of any sort are planned to produce as few fractures as possible, and present a strong contrast to methods of mining metallic ores, which must be crushed eventually and have fractures produced in as great profusion as possible. Shocks transmitted to a stone invariably make it more porous and more permeable and reduce its effective life, therefore methods of mining building stone involve as This building illustrates the fine detail of workmanship, unprotected sharp corners and thin edges, and tall narrow columns characteristic of marble structures. These features require exceedingly coherent stone, and preservation of these features for decades or centuries demands many special quarrying precautions to keep absorption to 0.14 per cent or less, a detail not essential to stone for coarser architectural types. few shocks as possible. This is singularly true for marble because marble structures are intended to have long life, greater delicacy of line, more gracefulness and fineness of sculpture than those made from any other structural material (Fig. 1). So that delicate lines may remain in almost perfect preservation for decades, or even centuries, it is important

Jan 1, 1938

By W. O. Hotchkiss

RECOVERY and profits in the mining business do not go hand in hand. Some part of an orebody can usually be recovered at a lower cost per ton than the whole orebody or a higher proportion of it. Similarly, the total of the profits that may be made from mining an orebody is in itself not a true measure of the value of the business. The yardstick for money value should be present worth, and this is particularly so for purposes of com-parison. A simple example, well within the bounds of practicability, illustrates these points: Assume a mine to have known ore reserves of 4,000,000 tons. The ore is of uniform grade but is so situated that 1,000,000 tons could be mined more cheaply than the remainder. Present operations are on the basis of complete recovery of the ores. Output is 100,000 tons per year at a profit of $1 per ton. It is estimated that the 1,000,000 tons of readily accessible ore could be mined at the same production rate but at a profit of $2 per ton. For an output of 100,000 tons each year at a profit of $1.00 per ton, the mine will have a life of 40 years; will produce $4,000,000 of total profit, and, at Hoskold rates of 8 and 4 per cent, will have a present value of $1,104,690. If only the easy one-quarter of the ore is considered, with an output of 100,000 tons each year, at a profit of $2.00 per ton, that part of the mine will have a life of 10 years, will produce total profits of $2,000,000, and at rates of 8 and 4 per cent will have a present value of $1,224,800. . Under conditions such as these, then, one-quarter of the reserve ore promptly mined is worth some 10 per cent more than the entire reserve would be on an average basis extending over the longer period. Assume further that one-half, or 2,000,000 tons, of the reserves could be promptly mined at the same yearly rate of 100,000 tons at a profit of $1.50 per ton. Then this part of the mine would have a life of 20 years, would produce total profits of $3,000,000, and would have a present value of $1,320,630; approximately 20 per cent greater than for the whole ore-body on an average basis for the longer period.

Jan 1, 1936