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By Zay Jeffries

OF the new production of non-ferrous metals in 1930 gold will rank first in value. We usually think of copper as the most important non-ferrous metal. The copper industry as a whole, that is, adding copper production to copper fabrication, is the largest non-ferrous metal industry. Prior to the world war; however, gold led in value of new metal produced. During the war copper passed gold in value, but gold regained its position during the 1921 depression. For the past several years copper has again passed gold, but in 1930 gold promises again to regain the lead. The gold producer has at times been called a social parasite, largely because we ' cannot eat or drink gold, or because we cannot use it for clothes or for the construction of buildings. Let us briefly examine this accusation.

Jan 1, 1930

By M. G. Corson

THE theory of hardening by interference with slip which has been so clearly developed by Jeffries and his co-workers requires that an alloy to be amenable to age or heat hardening should contain among its components some that will stay in solid solution at high temperatures and precipitate as a secondary phase on cooling. This secondary phase may be either a more or less pure individual element (chromium in the case of copper, anti-mony in the case of lead), or some intermetallic com-pound. Those cases of hardening which depend on the precipitation of a compound are not only the most frequent, but are also far superior in the efficiency of hardening obtained. However, the slip interference theory as stated in its most general form is not sufficient to foretell new cases of this type of hardening and also will not explain some phenomena of a more intricate nature. It is not sufficient that a secondary phase might be absorbed by the main one at high temperatures and precipitated at the lower ones. The kinetics of this precipitation and the accompanying. physical phenomena of dimensional changes play independent and highly important parts. These kinetics, while not yet sufficiently studied to he formulated in the shape of physicochemical equations, might find their expression-in a qualitative systema-tization of the phenomena of precipitation according to two different viewpoints. To begin with, we encounter the question as to the velocities of the precipitation and of the growth of the phase precipitated. To harden a metal in an efficient manner we must be able to control the precipitation on one hand and also to bring the total of the secondary phase to such a number and size of the particles pre-cipitated as, will produce a desirable hardening effect under commercially feasible conditions of. age or heat hardening. From this viewpoint six different cases may be dis-cerned.

Jan 7, 1928

By C. F. Jackson

THE work of, the Mining Methods Committee is now well under way. Following discussions previous to and during the February meeting, an Outline for Papers on Mining Methods was prepared, and over a thousand copies have now been distributed to committee men, to section secretaries and to members who have indicated any interest in the subject. The objective of the committee is to prepare a symposium on mining methods which will be of real practical value to the operator and engineer in the solution of every-day mining problems. It is planned to cover the entire field of mining in such a way that the different branches of mining, such as coal and ore (iron, copper, lead, zinc and precious metal) can benefit from the experience of the others at points where they have problems in common.. It is realized fully that each of these branches of mining possesses its own peculiar problems, but at the same time, there are prob-lems in connection with each, where the experience in others should be of value. The committee proposes to proceed along the following lines: 1. To present a general classification of mining methods, showing their inter-relationship, and at the same time .provide a common language for the discussion of mining methods and a nomenclature that will have the same meaning wherever used. A com-plete set of illustrations will accompany the classi-fication to make clear the terminology adopted and to show graphically the inter-relationship of methods. 2. To show the relationship between the physical characteristic of the deposit, the economic consider-ations and the. mining method., It is not proposed to treat this subject as a mere academic problem, but to secure reports from every mining company of impor-tance in this country, which will show what methods or modifications and combinations of methods have actually been applied and the physical conditions and economic considerations which have led to the adoption of these methods in each case. The Mining Methods Committee has drawn up an Outline for Papers on Mining Methods to be distributed among mining engineers and operators, giving in detail the information desired. This outline is the result of several months of careful thought and is a composite of the suggestions of many engineers and mining company officials from all parts of the United States.

Jan 7, 1922

By C. T. Holland

This discussion is concerned with those com-J- paratively infrequent bumps that eject material from the failed mass with enough energy to wreck heavy machinery and seriously injure or kill people. In such cases there is a loud report, and the pressure waves set up in the mine atmosphere wreck ventilation controls several hundred feet from the site of the failure. Vibrations are induced in the earth's crust which may be detected several miles from the point of origin, and explosive gases may be released in large quantities." Usually a dense suspension of dust is produced from the failed mass, together with dust placed in suspension by the resulting air blast. These rock bursts or bumps have also been called mountain shots, bounces, pillar bursts, and crumps. Such occurrences, when extensive, are serious catastrophes, and may force abandonment of the mine.' CAUSES OF ROCK BURSTS Rock bursts in coal mines have occurred in sev-eral places under diverse geological conditions, mining methods, and/or practices. A study of many such occurrences indicates that they depend on the following conditions: 1) cover thickness of 500 ft or more, 2) cover composed of strong members and having a strong member lying close to or on the coal bed, and 3) a floor that does not readily heave. The minimum thickness of cover under which coal mine rock bursts occur is based on observation. Under unusual circumstances involving very strong roof members and/or mining systems, and/or practices especially likely to induce bursts, a burst conceivably could occur under less roof. Under special circumstances rock bursts have occurred in marble quarries almost at the surface.' Furthermore, under very heavy cover it is likely that controlling roof members need not be as strong and as close to the coal bed to cause bumps. Just what constitutes a strong roof or roof member is open to question. Obviously the strength of a roof member is determined by its thickness, the distance between bedding planes across which little or no bond exists, the spacing and development of joints, and the inherent strength of the rock material. Strata sections showing roofs under which rock bursts in coal mines have developed are illustrated in Fig. 2. In several instances the strength of rocks composing the roof of mines developing bumps has been tested. The tests (Table I) show that these rocks develop considerable strength in compression, bending, and shear and that in some cases the strengths are very high. No quantitative data are available concerning joints in roof members over coal beds where rock bursts have occurred, but the author has examined many mines subject to bursts and has received the impression that joints in the shales immediately over the coal beds are always present and well developed. In the main sandstone or conglomerate members themselves, however, where observed, he has yet to see a fracture system indicating well developed joints. Undoubtedly joints are present, but the evidence indicates that they are few, poorly developed, and widely spaced. In a mine subject to bumps, moreover, actual measurements of roof spans up to 225 ft between supports under a cover of about 800 ft have been made before roof failure occurred. Such spans signify strong roof. In coal beds subject to rock bursts, the bottom rock is usually a sandy shale. A few tests (Table I) have been made on the floor rock of coal beds. Observations in mines indicate that they are usually weaker than roof rocks and that under load they show more plastic effects. Observation in ground subject to bursts invariably indicates a relatively strong floor highly resistant to heaving, although some heaving may occur. Other factors listed as favorable to rock bursts are: 1) mountainous surface; 2) steeply dipping beds; 3) proximity of faults, folds, and other similar geologic structures. Many bursts have occurred in mines under mountainous country, although many bursts in mines under a surface with little relief indicate that thickness of cover, not relief, is the essential factor. In steeply dipping beds, many bursts occur in mines that are essentially flat, and rock bursts have been recorded in beds dipping as much as 35o Most rock bursts in the U. S. occur in beds that dip less than 10 pct. It is also true that most U. S. coal is produced from beds dipping less than 10 pct. Geologically, faults are regarded as providing stress relief, but in the vicinity of faults, as well as sharp folds, it would seem that residual stresses could be present. The fact that rock bursts occur in areas remote from faults and sharp folds suggests that their presence is not necessary for this phenomenon to take place. There have been many bursts close to faults and folds, and it may be assumed that occasionally such structures accentuate their occurrence3 The conditions and circumstances under which they occur, coupled with the effects produced, leave In the Crowsnest Pass coalfield, British Columbia, a rock burst is estimated to have released 1.8 million cu ft of methane.

Jan 1, 1959

By A. S. Nowick, E. S. Machlin

ONE of the main criteria used to rate the heat-resisting properties of alloys is stress rupture.1 During a stress-rupture test a tensile specimen is held under a constant load at a constant temperature until it fractures. The chief measurement made during this test is the time required for rupture at the specific test stress and temperature. It was found empirically from a series of stress-rupture tests at a constant temperature that when the logarithm of the time for rupture is plotted against the logarithm of stress a straight line is obtained within experimental error.2~3 This method of showing stress-rupture data has been adopted by many investigators and the KACA.4 By interpolation and extrapolation from these plots, values of the stresses required to rupture the specimens (the rupture strengths) in 10, 100, and 1000 hr are obtained for specific temperatures. Alloys are then rated for a particular application on the basis of their rupture strengths at the rupture life that most nearly represents the application. Inasmuch as stress rupture is an important criterion in rating heat-resisting alloys, it would be advantageous to know the quantitative dependence of the time for rupture on stress, temperature, com- position, and structure. In order to obtain this information, an investigation was made at the KACA Cleveland laboratory during the spring of 1945. The theory of rate processes was used because it has been found to apply to certain processes such as chemical reactions, viscous flow, and creep that occur at a definite rate for given conditions. It was thought that stress rupture was such a process. An equation was derived that gives, for a given com- position and structure, the dependence of the time for rupture on stress and temperature. The investigation is part of a general program to provide information that will lead ultimately to the development of better alloys in order that the efficiency and power output of gas turbines used in aircraft propulsion can be increased. THEORY The theory of rate processes will first be discussed as a general theory. It will then be shown that if stress rupture of heat-resisting alloys can be treated as a rate process, certain equations must be satisfied. Later sections will then show that these equations are satisfied. General Theory of Rate Processes The theory of rate processes5 eveloped by Eyring and others has been applied to chemical reactions as well as to other processes such as viscosity of liquids and diffusion. In every case in which rate- process theory can be applied, there is a small subdivision, so that the macroscopic process is the net effect of all the small processes. This smallest subdivision is called the "unit process.'' For example, in a chemical reaction the unit process is

Jan 1, 1947

By G. Sandoz, D. A. Meyn

The fracture surfaces of specimens of titanium a1loys which exhibited susceptibility to subcritical crack growth in a wide variety of environments, including aqueous solutions, alcohols, hydrocarbon gases, carbm tetrachloride, and dry air, were examined. The dominant and characteristic fracture mode was cleavage. which became mixed with an increasing porportion of ductile fracture modes (dimples. and so forth) as the applied KI was increased. The cleavage plane in all the alloys was oriented at 15 deg from (0001) of the a phase. No indices could be assigned to the 15 deg cleavage Plane because of uncertainty as to which zone it belonged to. SLOW crack growth and delayed fracture take place in certain titanium alloys at stress intensity (KI) lower than the critical values for complete fracture (KIc) found in short-time tests for plane strain fracture toughness.' Such crack growth may take place in very dry air on sustained loading if the alloy contains a sufficient amount of hydrogen and if the stress intensity factor is higher than a threshold value designated KIH.2 Similarly, a number of environments such as water, alcohols, and hydrocarbons may cause slow crack growth provided the stress intensity factor exceeds the threshold value KISCC. In this paper it is intended to examine some fracto-graphic and crystallographic details of this subcritical crack propagation process as related to alloy composition, environment, and stress intensity. It has been previously reported that subcritical crack growth takes place in titanium alloys in aqueous environments by cleavage.2"6 The observations to be described here indicate that in the alloys investigated the mode of subcritical crack propagation is more dependent on the stress intensity during cracking than on the environment. The fracture mode is illustrated with photographs of the fracture surfaces at a wide range of magnifications. The crystallographic character of the cleavage mode is also presented and the results discussed. EXPERIMENTAL APPROACH The studies were made on four titanium alloys— Ti-8A1-1Mo-lV, Ti-5A1-2.5Sn, Ti-7Al-1Mo-lV, and Ti-0.350. Of these four alloys the first two were mill annealed and fine grained. The latter two were noncommercial and coarse grained, having been prepared for other experimental purposes. The crystallographic studies required a large-grain size. Consequently the fine-grained alloys were an- nealed in a vacuum at 1950°F and furnace cooled to produce samples for these studies. This treatment did not alter the microstructure significantly except for grain size. All the aluminum-containing alloys showed primary a with a network of ß-phase particles within the a grains; Figs. 1 and 2 show this microstructure for the specific case of fine-grained Ti-8A1-1Mo-1V. The cracks in the figures will be discussed later. Fractographic studies were made on all the alloys, but the electron fractographs displayed herein are from the Ti-8A1-1Mo-1V alloy in the fine-grained condition. Emphasis was placed on this commercial alloy because considerable information was available on the stress-corrosion cracking characteristics in a variety of environments. Sufficient supplementary studies of the alloy after the anneal to produce large grains were conducted to establish that the stress-corrosion cracking susceptibility and fractographic characteristics were not changed significantly. Thus it could be inferred that the crystallographic data obtained exclusively on large-grained specimens would apply also to fine-grained specimens. Fracture surfaces for study were obtained using precracked cantilever beam specimens loaded as described by Brown. The precracked section of a specimen was immersed in the environment of interest. Values of initial stress intensity factor Kli were chosen slightly higher than KISCC in order to obtain a fairly extensive region of slow crack growth. Fracture surfaces representative of a variety of stress intensity levels could then be examined because in the cantilever beam test KI increases as the crack propagates.

Jan 1, 1970

By R. W. Armstrong, D. H. Feisel

Self-diffusion in pure crystalline solids has been described through extension of the Cohen and Tum-hull volume -fluctuation model originally proposed for diffusion in simple liquids. It is shown, for a number of crystalline solids, that the self-diffusion coefficient, D, obeys the relationship where a is the lattice spacing, v the Debye frequency, Z' the lattice-volume fluctuation per atom required for a diffusion jump, and (?V/Vo) the relative increase in the lattice volume resulting from thermal expansion between O°K and the temperature under consideration. The calculated value of Z' is dependent upon the difiusion mechanism and the lattice geometry. ThE need for an increased understanding of mass-transport processes in crystalline solids has resulted in much research to determine rates of self-diffusion.' For several metals (e.g., copper, silver, and iron), the experimental values of the self-diffusion coefficient, D, have been determined over a large interval of temperature and the accuracy of D has been investigated through repeated experiments. Also, a number of empirical and theoretical diffusion studies have established a rational basis for understanding the D values for the different elements.2"6 The empirical diffusion analysis by Sherby and simnad6 supplied the main stimulus for the present study. Sherby and Simnad, reviewing the self-diffusion data for a substantial number of pure crystalline solids, suggested that sufficient data were available to establish with some certainty the apparent intrinsic material properties which influence D. Without explicit regard for any mechanism of diffusion, these investigators obtained an empirical relationship for D which correlated the self- diffusion coefficient for each element with the melting temperature, crystal structure, and valence of the particular element. Their analysis is only unsatisfactory in that the effect on D of crystal structure is not very clear and the valence to be assigned to an element is not always straightforward. The present study is an attempt, from a very different viewpoint from that of Sherby and Simnad, to establish a basis for understanding the self-diffusion coefficients for crystalline solids. This analysis was undertaken for the purpose of developing a general expression for D which would explicitly depend on the mechanism of diffusion. The main result of the study is that diffusion in crystalline solids may be described in terms of a volume-fluctuation model which was originally proposed by Cohen and Turnbull7 to describe diffusion in simple liquids. The model appears to be useful for predicting self-diffusion coefficients in crystals. The following sections describe the volume-fluctuation model for diffusion, the application of this model to crystals, and the resultant agreement with experimental data. 1) THE VOLUME-FLUCTUATION MODEL FOR DIFFUSION Cohen and Turnbull7'8 developed their model for liquid self-diffusivity for the purpose of describing certain properties of liquids, glasses, and the liquid-glass transition. A hard-sphere model for the liquid structure is used. In this model, the size of a spherical molecule or atom is fixed for all temperatures by the interatomic spacing at the absolute zero of temperature. At any temperature above O°K, the atom is viewed as being contained within a larger spherical cage defined by the interatomic spacing of the atoms at that temperature. A random distribution of varying cage sizes is assumed to exist in the liquid. An individual diffusion jump occurs when the free volume of an atom (the volume of the cage containing the atom minus the volume of the atom) is large enough for the atom to jump out of its cage. With this physical picture of diffusion in liquids, Cohen and Turnbull derive the following equation for self-diffusivity: D=Doe-yv*/vf [1] where Do is the product of three factors which are the diffusion-path geometry, the diffusion-jump distance, and the velocity of the diffusing atom, v*

Jan 1, 1964

By E. A. Hopkin

Laboratory tests conducted by the author. together with actual field experience in Canada. have indicated the magnitudc of some of the factors affecting ability of drilling mud to clean the hole. A correlation was observed between funnel viscosity and particle slip velocity. A relationship was also observed between the Bingham yield value of the mud and the particle .slip velocity. Laburatury tests indicated little change in slip velocity with funnel viscosities up to ahout 80 sec/qt or to yield values of aboul 15 lb/100 .sq ft. The lip velocity of the partic1e.s. studied vuried from 160 ft/min with water to neerly zero for high mud viscositie. lncreasing the mud density, creating laminar annular mud flow or rotating the drill pipe Mlay also improve the carrying capacity of mud. Field tests indicated that during fast upper-hole drilling, the rate of cutting removal must he sufficien to maintain the concentration of cuttings in the annulus at less than 5 percent by volume to prevernt balled-up drill collars and .stuck drill pipe. INTRODUCTION In the Mid-Continent area, hole cleaning during rotary drilling normally involves the use of low-density drilling muds with funnel viscosities varying from 26 to 80 sec/qt. However, frequently it is necessary to raise the mud viscosity in excess of 200 sec/qt to clean the hole. In addition, field experience has indicated that during very fast upper-hole drilling, annular mud velocities considerably in excess of the maximum slip velocity of the cuttings (normally considered to be 120 to 150 ft/min) are necessary to prevent balling the bit and drill collars. In view of these variations in mud properties and circulation rates necessary to clean the wellbore, a study of factors affecting hole cleaning and the relative magnitude of each was undertaken. The study was also prompted by the knowledge that a drilling mud with properties close to those of water would drill at rates several times that of a viscous mud. The carrying capacity of these near-water muds was not clearly understood, however, and many drillers were reluctant to use them. DISCUSSION EFFECT OF MUD PROPERTIES ON DRILLING RATE The effect of mud properties on drilling rate has been studied by a number of investigators. 1t is clear from their work that mud properties close to those of water will significantly improve drilling rate and bit life. If the water-type mud will also effectively clean the hole and cause no logging or formation impairment problems, the choice of an appropriate drilling fluid is clear—use water. Often, however, a water-type drilling fluid is not capable of effectively cleaning the hole. THEORY OF PARTICLE SETTLING The forces acting on a particle that is allowed to settle through a fluid quickly reach equilibrium, and the particle settles at some constant velocity referred to as the slip velocity. The slip velocity of any particle depends upon a number of factors such as density and viscosity of the fluid, the volume, specific gravity, shape and roughness of the particle, and upon the shape and area of the projected face of the particle at right angles to the direction of relative fluid solid movement. Brown' expressed this relationship for spheres in Newtonian fluids in the following equation. where v, = slip velocity D, — diameter of sphere p, = density of spheye p, = density of liquid /a = friction factor g = constant. The friction factor f, varies as the size, shape, surface roughness and slip velocity of the body, and as the density and viscosity of the fluid varies. WaddelV ound experimentally that where dynamic similarity exists. f, was a function of the particle Reynolds number (NRe) of the sphere (Fig. 1). Fig. 1 shows that f, for spheres varies from over 10 for low NKe numbers to 0.44 for N,,. over 600.

By C. Kremer Bain

DURING the past several years of diamond drilling in Washington County, Mo., the St. Joseph Lead Co. has discovered a concentration of commercial lead-zinc ore at four different points within an area of 36 square miles. The largest and to date the most promising group of these orebodies is located in the Indian Creek area. It was considered to be of sufficient value to warrant development. The Indian Creek area is in the center of the northern half of Washington County, 11 miles northwest of Potosi, Mo., the county seat. The location is readily accessible from Potosi by car or truck over the all-weather Missouri State Highway No. 114. The topography is one of rolling relief, varying from an elevation of 700 ft above sea level on Mineral Fork and Indian Creek to a maximum of 1176 ft at High Point Tower. It is divided in equal halves between the drainage to Mineral Fork and to Indian Creek. The shaft site at 1060 elevation is on the divide between the two drainage areas. The Indian Creek side is rough and heavily wooded, with only a few cultivated clearings. The slopes to Mineral Fork are more gentle and rounded, with much of the area cleared for farm land. Most of the surface is covered with Potosi and Eminence formations, which show little evidence of any structure. Ore structure was worked out by extensive diamond core drilling, with holes varying in depth from about 700 to 1300 ft. As of Oct. 1, 1950, 218 prospect holes had been drilled within the 36-square mile area. The ore is disseminated galena with considerable accompanying sphalerite in the Bonne Terre forma-tion in the shape of irregular blanket-type deposits. The main controlling structural feature of the outlined mineral zone is a buried pre-Cambrian rhy-olite-porphyry ridge extending partly through the Bonne Terre formation, which laps against the por phyry and also covers it. The mineralized zone parallels and forms an irregular halo around the porphyry ridge and is concentrated in the Bonne Terre formation where the La Motte sandstone is cut out by the porphyry ridge. This is a very common mineral occurrence in the southeastern Missouri lead belt district. The La Motte sandstone, which normally underlies the Bonne Terre formation, is thus cut out entirely. In this area the Bonne Terre is usually about 275 to 320 ft thick, the La Motte varying in thickness from zero up to 400 ft. Commercial concentrations of ore are indicated at several places, the most notable being at the shaft site where an orebody at least 4000 ft long with widths of 500 to 600 ft has been outlined. The total thickness of mineralized rock reaches 150 ft in some holes, although total ore thickness runs from 8 ft to about 60 ft, often in more than one layer. Preliminary Planning Ore reserves as outlined lend themselves to open-stope mining with trackless haulage and mobile loading machines and drilling equipment. This type of equipment has proved to be very efficient during recent years in the company's lead belt operations. After a study of bids for shaft sinking and an estimation of comparative costs, it was decided that the shaft would be sunk by St. Joseph Lead Co. personnel using company equipment. Since the plant site is about 26 miles from the company's nearest lead belt operations, it was necessary to plan a complete surface plant, including mill, shops, office, change room, and warehousing facilities. Immediately following the filing of an application for a certificate of necessity, a headframe was selected for which detailed drawings were already available. The order was placed for fabrication so that it could be delivered and erected in time to serve for sinking the shaft. This eliminated the expense of a temporary headframe. Drilling was started on two churn drill holes near shaft location, and two 1000-gpm deep well pumps

Jan 1, 1954

By D. F. Gibbons

THIS investigation was undertaken in order to gain further information on the mechanism of plastic deformation of iron at temperatures between room temperature and 77.2°K, and also to contribute to our understanding of the low temperature brittleness phenomenon that occurs in both the tensile and impact tests. It was decided to study as pure an iron as possible and to use the tensile test in order to simplify the problem as much as possible. Two series of iron were used throughout the investigation: iron A, obtained from the National Research Corp. and supplied as gas-free, high purity iron; and iron B, obtained from Fast' and produced by melting iron under purified hydrogen. Typical analyses of samples of both irons, after fabrication, are given in Table I. The main difference in composition of these irons is in their nickel and oxygen contents. Nickel has a very large solid solubility in iron. However, oxygen has an extremely small solid solubility. An attempt was made to reduce the oxygen content still further by remelting under purified hydrogen. This was successful in reducing the oxygen content to -0.0006 pct. However, no results on tests of this iron are included, since difficulty was encountered in fabricating the ingot. Wire specimens 1 mm in diameter were used for the investigation. The wires were produced from the ingots, as supplied, by cold rolling and swaging, with intermediate vacuum anneals at 700°C. Care was taken to reduce preferred orientation in the wires to a minimum by keeping the percentage of reduction in area between anneals of 30 to 40 pct. X-ray transmission photographs showed no indication of preferred orientation. The final grain size of iron A was 20 to 24 grains per linear mm and of iron B, 16 to 18 grains per linear mm. All specimens were tested in the decarburized and denitrided condition unless otherwise stated. The procedure was to pass hydrogen, saturated with water vapor at 26oC, over the specimens at 730°C for 2 hr. The specimens were quenched in iced water and then annealed in a vacuum of - 5x10-6 mm Hg for one day at 560°C to remove hydrogen. Higher temperatures were used for the vacuum anneal but this temperature was found to be quite satisfactory in removing hydrogen. The specimens were slow-cooled after the vacuum anneal. Where it is stated that the specimens were carburized, the specimens were given an identical decarburizing treatment and then carburized by passing hydrogen, saturated with pure n-heptane vapor at 0°C, over the specimens at 730°C. The specimens were then homogenized at 730°C for 2 hr in dry hydrogen. After the carburizing treatment the specimens were given the same vacuum anneal as for the decarburized specimens. The carbon content was determined from the maximum value of the internal friction carbon peak.2 Apparatus Fig. 1 shows a diagram of the tensile apparatus, with half the cooling coil removed. The cooling coil enabled temperatures from 200" to 77.2oK to be obtained. The apparatus was designed to fit a standard Tinius Olsen Universal tensile machine. The apparatus consisted of the rigid plate A which carried two carefully machined hooks H. These hooks attached the plate firmly to the moving crosshead of the tensile machine. The lower grip B was rigidly suspended from the plate A by three stainless steel rods. The upper grip C was joined to the upper grip of the tensile machine by the stainless steel rod E. The lower part of the apparatus was surrounded by a Dewar vessel, which was made a sliding fit inside the brass collar D. The specimen was held in a clamp which fitted into the grip, forming a ball and socket joint (see inset a). This was to attain as nearly pure

Jan 1, 1954

By James Howe

EVERY engineer and user of wire rope is desirous of information that will enable him to determine whether the performance of any particular piece of rope is satisfactory, and what conditions can be changed so as to increase the life of a rope. In most cases, it is far from easy to analyze the conditions of service and tell which is the greatest factor in determining the life of wire rope. If we start on a layout for an entirely new rope system, the task of making conditions satisfactory is simplified so far as the engineering details are concerned; but if the plant requiring wire rope is in operation, any change is likely to involve the expenditure of consider-, able money to replace and change over machinery that must be kept in constant operation, because a large monetary loss will result from a shutdown for even a few days. Often wire rope is kept operating under bad conditions, as the user thinks that it is cheaper and quicker to replace the rope than to make alterations in the hoisting machinery. A typical case is a metal mine operating in what is now almost the center of a large mining city, where it owns a few acres of mineral rights. It was expected that the shaft would go to a depth of 1000 ft. (305 m.), so a moderate sized rope, about 1 ¼ in. (31.7 mm.), was used on a 6-ft. drum with a 7-ft. head-frame sheave and rather short lead from drum to head sheave. This mine has gone deeper each year until, it is now 2500 ft. deep and the rope speed has been increased from 1500 ft. per min. to over 3000 ft. The original rope just filled the drum in one layer, now it overwinds three layers. The original ropes were probably 6 X 19 crucible steel and lasted from 12 to 18 mo.; now, the highest grade plow steel is used, yet the average service is only about 6 mo. The cause is not hard to find. If the engineers had known at the outset what would be done with this hoist, the design would have been very different. Conditions at this mine, from a wire rope standpoint, have gradually become worse and it is difficult to see how rope service on this hoist can be com-pared with the service of previous years with any fairness to the wire-

Jan 2, 1922

By Eugene Grace

IN THE careers of the men to whom I have referred we find typified the development of the chief prob-lems of engineering. The first is to shape and direct the forces of nature and thus to bring the world's resources to add to the comfort and welfare of man-kind. That, in a word, is the problem of production. Engineers have made a supreme contribution to the solution of that problem. But I feel that we have two somewhat newer branches of engineering which must command more and more of our attention. Those are what might be termed commercial and human engineering. Of what value is all our efficiency in pro-duction if we do not distribute efficiently, economically and effectively? And of what value is any of it unless we can add to the happiness and deeper satisfaction of those engaged in industry, as well as those who enjoy its -products? I predict that the outstanding advances in business over the next ten years will be in improved merchan-dising and distributing methods. Herein lies a wide field of opportunity for the engineer. We have briefly reviewed certain qualities of engi-neers who have become successful business executives. Is it possible for us to say that the material success of all these men was due to any one characteristic com-mon to each one of them? Indeed, I venture to assert that there is one quality which, in the last analysis, is determining as to whether any roan shall realize material success in this world of ours. That quality-so notable in the character of each one of the men I have named-is sound judgment. Moments arise in every life when it is necessary to say "yes" or to say "no" to a particular proposition or to a proposed line of action. It is the man who says "yes" at the proper time and "no" at the proper time who, in the final analysis, realizes business success. The ability to do this wisely is the mark of sound judg-ment, which is necessary in a business executive. I have known many business men seemingly slow in their mental processes, possessed apparently, of little imagination and of none of the flair which gives fasci-nation to so many characters, and yet who, when crises come-be they big or be they little-are able so to steer their business courses that they move in the right direction instead of into shallow waters or upon the rocks of trouble.

Jan 4, 1928

By E. A. Anderson

THIS seems to be the year for superlatives in A.I.M.E. meetings. The programs of the various Divisions and Institute committees offered an abundance of interesting and valuable information in the form of technical papers, symposia. and lectures to large and interested audiences. The Institute of Metals Division may hold up its head with pride for its own program. With six technical sessions, three full-day symposia, and the annual I.M.D. dinner, four meeting days were not enough and many simultaneous sessions were required. The quantity and quality of the paper were equaled by the numbers and interest of those attending.

Jan 1, 1944

By Hans Lundberg

GEOPHYSICAL methods as described in technical articles generally fail to answer the questions of prospectors and geologists as to which method they should apply and what information they may expect from their application. This article is an attempt to discuss the use of electrical methods with special reference to the prospecting for orebodies and the map¬ping of geologic structure. Especially on virgin ground, geological reconnaissance should precede electrical prospecting, with the object of outlining carefully the orebearing rock and determining the possibilities of elec¬trical prospecting. No electrical survey will then be carried out on ground which, for geological reasons, may be considered barren or where the electrical meth¬ods are inapplicable. As the success of electrical prospecting depends on the difference in conductivity between the ore and the country rock within which the orebody is inclosed, the conductivity of the two should be considered and de¬termined, if possible. The conductivity of an orebody depends on the distribution of conductive ore minerals and, in addition, on its size (length, width and depth). Most minerals with metallic luster show good electrical conductivity; for instance, the sulfides. Zinc-blende is an exception, but as it is often associated with the ore minerals of good conductivity (for instance, pyrite or galena), there is likelihood also of finding zinc.

Jan 1, 1930

By M. J. Pool, P. J. Spencer, R. V. Miner

The partial molar heat of solution of rhodiunz in liquid lin and Rh-Sn alloys has been measured as a function of rhodium concentration at 700" , 725" , 750" , and 775°K. The values at infinite dilution are very exo thermic, ranging from -29,950 to -28,260 cal per g-atom Rh at 700" and 775"K, respectively. At the solubility limit the heat of solution becomes sharply nzore exothermic and has permitted the liquidus boundary to be accurately established at each temperature. From the measurements in the two-phase region of liquid Plus RhSn, the heat of formation of RhSn,has been determined. A large increase in the heat of formation between 725" and 750°K suggests the possibility of a phase transformation in this compound. V ERY few measurements have been made of the heats of solution of transition metals in liquid tin; yet those values that are available are of great interest because of their very large exothermic nature. For example, the heat of solution at infinite dilution of palladium in tin has been measured as about -26,000 cal per g-atom (625" to 800°~),' while the heat of solution at infinite dilution of platinum is even more exothermic at -28,591 cal per g-atom (914°K).' These values are of the same order of magnitude as the heat of formation of many intermetallic compounds and as such clearly indicate that very strong bonding must exist between the solute and tin atoms in the liquid solutions. Rhodium might be expected to display similar solution characteristics in tin in view of its close electronic resemblance to palladium and platinum. Since no thermodynamic data are available for Rh-Sn alloys, rhodium was chosen as an appropriate solute for further investigation of transition-metal systems with highly exothermic heats of solution at infinite dilution. EXPERIMENTAL The heat of solution of rhodium in dilute Rh-Sn liquid solutions was measured as a functlon of rhodium concentration at 700°, 725", 750°, and 775°K. The liquid-metal solution calorimeter used in this work has been fully described elsewhere. At the start of each series of measurements, the solvent bath consisted of about 0.5 g-atoms of 99.9+ pct pure tin. To this was made a number of small rhodium additions, about 0.0005 g-atoms each, and the heat of solution was measured for each. Rhodium of 99.9+ pct purity in powder form was used in order to promote rapid dissolution in the liquid tin. The powder specimens were contained in tin foil stated to be purified (lead-free). This foil was found to have no measurable heat of solution in pure tin so the effect of any impurities could be neglected. The energy equivalent of the calorimeter was experi- mentally determined by dropping tungsten and/or tin specimens at intervals during each series of rhodium drops. The tungsten and tin used were 99.95 and 99.999+ pct pure, respectively. The only heat effect due to a tungsten drop, or a tin drop at low rhodium concentrations in the bath, is the sensible heat of the specimen. The heat content of these materials is well-established and is presented in the compilation of Hultgren et al. 4 As the rhodium concentration in the tin bath increases a small heat effect arises from the reaction: Sn (liquid, T) — & (soln, T) where T is the temperature of the tin bath. Where necessary, this heat of solution of tin was determined by Gibbs-Duhem integration, and corrections were made to the heat effect of the tin calibration specimens and the tin foil containing the rhodium specimens. RESULTS AND DISCUSSION The calculated values of the heat of solution of rhodium in dilute Rh-Sn alloys as a function of composition are shown graphically in Fig. 1. The values have been corrected for the sensible heat of the specimens, initially at 273"K, and apply to the reaction:

Jan 1, 1969

By KENNETH W. GREENAWALT, William Greenawalt

THE patent system, through which an inventor is given exclusive right to his invention for a limited period as a reward for his industry and in reimbursement of his expenditures, originated in England in the famous "Statute of Monopolies," enacted in 1623. The first patent granted in America was to Samuel Winslow, in Massachusetts, in 1641. The basis of the patent system of the United States is a provision in the Constitution giving Congress the power to secure to inventors for a limited time the exclusive use of their discoveries. The first legislative enactment was the law of 1790, which was placed on the statute book after Washington had addressed Congress in its favor. Under this law, the Secretary of State, the Secretary of War, and the Attorney General constituted the board for the examination of patent applications and the granting of patents. The first Secretary of State, Thomas Jefferson, became the first administrator of the patent sys- tem in this country. He personally examined every application filed during his term of office.

Jan 1, 1930

By M. J. Saarivirta

A high-purity copper-zirconium alloy system was imesti-gated. The zirconium content of the alloys studied varied from 0.003 to 0.23 pet. The solid solubility of zirconium in copper and some physical and mechanical properties of the alloys have been determined. By proper heat treatment, Cu-Zr alloy can develop a high electrical conductivity and resistance to softening at temperatures up to 500°C (930°F). This combination of desirable properties makes this alloy superior, to other com-merzcrrl copper base alloys for- use in the electrical conductor field. DEMAND for high conductivity copper alloys that retain their mechanical properties at elevated temperatures is growing rapidly. At present, copper-base alloys such as copper-silver and copper-chromium are used where these characteristics are required. As an example, commutators in electric motors are often made of these alloys. However, the life at elevated temperature of commutators made of copper-silver alloys is much shorter than the life of the same part made of copper-chromium and copper-zirconium alloys. Copper-silver alloys are subject to creep and subsequent failure when the service temperature exceeds several hundred degrees centigrade. Use of copper-chromium alloys has been known for the past several years, but little information is available in the literature concerning the properties of alloys in the copper-zirconium alloy system. Some work had been directed toward determining the solubility of zirconium in copper as well as determining properties of the Cu-Zr alloys. These investigations have revealed the superior high-temperature and electrical conductivity properties of copper-zirconium alloys over copper-chromium alloys. The United States Metals Refining Co., Carteret, N. J. has recently produced OFHC R copper-zirconium alloys for experimentation and evaluation. Because OFHC R copper contains no appreciable oxygen, no harmful oxides are formed and the full benefit of Zr as an alloying addition is obtained. This paper describes the results of this work. It contains room-temperature and some high-temperature data which have been obtained after various processing techniaues. Actual elevated temperature properties are being determined and will be reported in a separate paper. Preliminary results obtained at elevated temperatures suggest that the Cu-Zr alloy is superior to other high conductivity copper-base alloys. WORK PROCEDURE The high-purity oxygen free (OFHC R) copper-zirconium alloys with zirconium content ranging from 0.003 to 0.23 pct were cast into 4-by 4-in. wirebars by both continuous casting and conventional casting methods. Zr was added in the form of a master alloy containing 30 pct Zr and 70 pct Cu. Castings were analyzed for zirconium and nine bars containing various amounts of zirconium were selected for this study. The results of analyses and the sample numbers are given in Table I. Typical analyses of OFHC R copper are also shown. The following properties were studied: A) Solid solubility of zirconium in copper. B) Effect of zirconium on properties of copper. C) Effect of combined working and heat treating on properties of Cu-Zr alloys. The solid solubility of zirconium in copper was determined by metallographic techniques. Specimens for this phase of the investigation were hot rolled at 900oC (1650oF) to 0.250-in. rod. The rolled rods were cut into 2/3-in. long specimens and solution annealed at 950 °C (1740°F), 980°C (1795 °F). and 1020 °C (1870 °F) for 6 hr and quenched in water. In order to find the solid solubility limits at lower temperatures, the homogenized specimens were reheated at various temperatures for 1 hr and quenched. The physical and mechanical properties were determined on 0.250 in. rod, 0.132- and 0.081-in. wires. The wires were cold drawn from the 0.250-in. rods after they were solution annealed at 980 °C (1795°F) and quenched in cold water. Mechanical and electrical properties were determined on cold drawn and

Jan 1, 1961

By Sheldon P. Wimpfen

EVER since the Phoenicians roamed the known world in quest of metals to harden their helmets and precious metals and gems to adorn their ladies, many other nations have sought metals in the far corners of the earth. During the past 75 years American engineers have been among the foremost in seeking for and developing ore deposits. They have been responsible for many of the principal discoveries and for the application of modern methods to mines in the far comers of the earth. American mining engineers with a zest for travel and an insatiable appetite for metals have also introduced throughout the world many articles made of metal which we consider essential to everyday life. Production and consumption of these metals in many foreign countries has brought to these countries an increased standard of living and added tax revenue to their governments. But unfortunately engineers from this country are no longer given ready access to all the countries of the world. This is not only unfortunate for American engineers but also for the countries that have adopted the exclusion policies and especially so since time has proved that in countries where the American engineers have gradually been excluded there has been a significant decline in the progress of the mining industry. Removal of these barriers to professional men would aid immensely in the world-wide development of the mineral industries. New areas brought into production under the guidance of American engineers with their exceptional know-how would provide more jobs for nationals of the countries involved and a better standard of living for the nations as a whole.

Jan 1, 1946

By Arthur Taggart

THE following conclusions on the work of the Hardinge mill are based on data furnished to the writer by the Hardinge Conical Mill Co. in the form of the mesh cards hereto appended. Energy units (E. U.) and relative mechanical efficiencies (R. M. E.) are computed by the "volume method" of Stadler.1 Screen apertures used are the average apertures of testing screens of the meshes given. Card 122. June 28, 1912. Vipond Porcupine Mines Co., Ltd., Schumacher, Ont., Canada. Ore from mill bin. Gangue, quartz and basalt. 4.5 ft. by 13 in. ball mill. Capacity, 48 tons per 24 hr. Charge, 4,000 lb. balls. Speed, 33 rev. per minute. Horsepower, 15 to 17. Water, 100 per cent. by weight. (50 per cent. ?) Product deslimed and oversize reground-in pebble mill, see Card 113. Feed to mill through 2-in. mesh.

Jan 7, 1915

By N. W. Sager, H. W. Mossman

The arrangement and general dimensions of the reverberatory furnaces and waste-heat boilers for the Nos. 2 and 3 smelting units at the McGill plant of the Nevada Consolidated Copper Corporation are shown in Fig. 1. Each of the two reverberatory furnaces has its own set of waste-heat boilers, and before February, 1932, each furnace, when it was in operation, delivered waste-heat gases to its own boilers only. In January, 1933, the idea was suggested of using some of the waste-heat boilers as economizers to operate in conjunction with the waste-heat boilers that were generating steam. The execution of this idea gave rise to the gas-flow scheme depicted in Fig. 1, the advantages of which were obvious, particularly so in view of the fact that for some months prior to the adoption of this scheme the smelting had been confined to No. 2 furnace, with No. 3 furnace and its boilers idle. The waste-heat gases from No. 2 furnace pass through the boilers serving this furnace as steam-generating units, thence through the original exit duct to a point where a bulkhead diverts the gases in a reverse direction through two of the boilers of No. 3 furnace. After the gases have traversed these two boilers, another bulkhead placed in the duct between No. 3 furnace and its boilers causes them to traverse still one more boiler, from which the gas path leads to the stack. In this scheme the last three boilers traversed by the gases, i.e., the boilers behind No. 3 furnace, function as economizers and preheat the feed water for the two steam-generating units directly serving No. 2 furnace. This discussion will give consideration to the results obtained in waste-heat recovery by the scheme shown in Fig. 1, and, further, will compare these results with those obtained before the boilers of No. 3 furnace were set up to act as economizers, but before going into the detail of heat generation, distribution and recovery, will present some additional details of the equipment. All boilers in this waste-heat plant are of the Stirling type. The two behind No. 2 furnace, acting as steam-generating units, of class 13, are 40 tubes wide and rated at 1112 boiler hp., while the three boilers behind No. 3 furnace, acting as economizers, are also of class 13, but 28 tubes

Jan 1, 1934