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By Robert Franke

In view of the prominence which the conical mill has attained in the fine-crushing field within the few years since its introduction, the following comparison with its more mature forerunner, the Chilean mill, based on extensive tests, is submitted in the interest of the milling profession. Soon after designing the concentrating plant of the Miami Copper Co. in 1909, the Hardinge conical mill made its appearance in the milling forum. Its possibility as a suitable crushing device for the plant was well recognized, but in view of the lack of commercial demonstration, at the time, as to capacity, efficiency for desired product, and the still more uncertain factors of cost of maintenance and power consumption, it was deemed that the immediate adoption of this machine throughout the plant would be a hazardous undertaking. For these reasons it was decided to equip the majority of the immediately required units of the plant with Chilean mills, the fine-crushing proficiencies of which were better known, and one section with Hardinge mills, to serve as a test unit for the guidance of future installations and replacements. Thereby, after 1.5 years' operation with both types of mills, a thorough test as to metallurgical efficiency and cost economy has been obtained. The conical mill used in these tests is the 8-ft. Hardinge pebble mill, having a cylinder 22 in. in length. The cylindrical portion of this mill is lined with cast-iron liner plates, and the conical extensions with silex bricks bound together by cement. Each liner plate carries a projecting lifter, the function of which is to increase the height of drop of the lifted material. Danish No. 5 pebbles, obtained from the coast deposits of Denmark, are used for the grinding charge. The Chilean mill used is a fast-running, 3-roller, 6-ft. Saturn mill, with screens of 0.037-in. opening. The feed to these mills is the oversize of Callow screens having 0.029-in. openings, which follow rolls crushing to 0.5 in. For the ore of this mine, a moderately hard but very fissile schist,

Jan 1, 1914

By Tell Ertl, Ernest E. Burgh

The Bureau of Mines is operating an oil-shale mine 10 miles west of Rifle, Colo., as part of its Synthetic Liquid Fuels program. The purpose of operating this mine is twofold: First, to supply oil shale to an experimental Processing plant; and second, to develop practices and select methods for mining oil shale on a commercial scale at the lowest practicable cost. The second purpose—that of finding out how to mine oil shale most cheaply—entails considerable mining research. Since the drilling of oil shale probably will be one of the major items of the mining cost, fattors that influence drilling speeds were investigated. One phase of the drilling program was the development of a successful hard-surfaced rock-drill bit1 that can be used for drilling long holes in oil shale without changing bits. During that phase, drilling speeds were measured and drill cuttings were collected for assay and for screen sizing, when the cuttings from the individual tests were compared, a definite relationship was shown to exist between the drilling speed and the coarseness of the drill cuttings. Procedure Measurement of Drilling Speeds All drilling in the tests was done with a Model UMB-D-99W Gardner-Denver wagon drill. Round-lugged drill steel, 141 in. in diameter was used in 6, 12, and 18 ft lengths with 1/8-in. Timken H-type bits hard-faced with acetylene tube borium. The tests were made in the lower adit of the Bureau of Mines oil-shale mine; the grade of the oil shale drilled ranged from 18.6 to 42.7 gal per ton, During the experiments air pressure varied between 75 and go psi while water pressure remained fairly constant at 75 psi. All holes were drilled almost horizontally. Each drill hole was thoroughly cleaned of cuttings after being collared. The advance of the drill along the carriage was measured and recorded as the drilling speed in inches per minute. Method of Collecting Cuttings TO facilitate the collection of cuttings, each drill hole was collared in a smooth, vertical portion of the oil-shale breast (Fig 1). A galvanized-stee1 sheet was fastened to the breast below the area in which the hole was to be drilled. The cuttings washed out of the drill hole by the drilling water were guided by the steel sheet into a wooden box. The cuttings that remained in the drill hole after the drill was withdrawn were scraped out and placed in the same box as the cuttings washed out of the hole. After the cuttings from a I-min. drilling interval were collected, they were placed in flat metal pans. The fines were allowed to settle and the clear water was decanted. The cuttings then were dried in the sun.

Jan 1, 1949

By D. J. Carney, J. Chipman, N. J. Grant

G. A. Moore—The tin-fusion method has been a very favorable possibility for many years. The authors apparently have settled the question that delayed the method for a long time by showing that no hydrogen is absorbed in the tin. This, of course, is very important. I want to make a few remarks concerning the absolute accuracy of analysis, which must be the final basis for deciding among the various methods. From the figures in the paper, there seems to be some remaining slight discrepancy on the actual amount of hydrogen present in various samples which may be presumed essentially identical. (This is of the order of the precision of individual analyses but appears in averaged results.) From the analyst's viewpoint, the tally of hydrogen content can be regarded as occurring in three portions. First is a large portion which comes off easily and automatically during sample storage and later on heating in the apparatus. This is fairly easily analyzed. Second is an item which may be either positive or negative in the tally sheet. In warm or hot evolution, this is a portion which, in practice, can never be re-

Jan 1, 1951

By Marcel Daly

THE writer has devoted a number of years to practical operations and to the study of geology in the oil fields. In consequence, he has been brought to investigate the theories advanced to account for the accumulation of oil and gas in commercial deposits. It is the result of these investigations and his personal conclusions that he wishes to sum up in this paper. The writer is an advocate of the organic origin of petroleum found in pools. He has been led to believe that the present theories of oil and gas accumulations are incomplete and, in certain respects, incorrect, although they may embody certain elements of truth; that the forces that are called upon to explain the movement are only secondary forces in the process, and insufficient, by themselves, to cause this movement; and that the phenomenon of accumulation is of much larger order than heretofore admitted and bears an intimate relation with the general as well as with the local deformations of the crust and is a direct consequence and a mechanical effect of these deformations to which the term "diastrophic" has been applied. As a complement to this theory, the writer offers a new interpretation of the "rock pressure" and of the mechanism of the "sealing up" of this pressure in oil and gas pools.

Jan 7, 1916

By E. C. Hopkinson, A. H. Youmans, R. A. Bergan, H. I. Oshry

A new log has been developed for quantitative formation evaluation which is based on a measurement of the length of time slow neutrons survive before they are captured in the rocks and fluids. The logging instrument employs a cyclically pulsed neutron generator and a gated scintillation counter which is synchronized with the source. The source emits short, intense bursts of 14 mev neutrons once every 1,000 microsec and is quiescent between bursts. During the period the source is quiescent, the detector is electronically actuated for two independent preselected intervals. A comparison of the counting rates during these two intervals gives a measure of the rate of decay of the slow neutrons and of the associated gamma radiation. The average neutron lifetime in most earth formations is in the range from 50 to 500 microsec. It can be measured during a continuous logging operation at conventional logging speeds. The design of the logging instrument is described and the results of tests are compared with theoretical predictiom. Formulas are developed which give the relationship between log response and formation properties. It is shown that the method is particularly sensitive to formation fluid salinity, and that salt water saturation can be measured accurately in either cased or open hole. The measurement can be made independent of borehole size, fluid type, casing and tool position in the hole by properly selecting the intervals during which the measurements are made. The results of tests with a prototype logging tool are given. INTRODUCTION A new nuclear logging system has been developed which employs the Accelatron,* an accelerator-type neutron source, and accurately measures formation brine saturation in an entirely new way. It has produced a type of formation log with better sensitivity, greater sampling depth and simpler quantitative interpretation than any other nuclear log thus far suggested. The new Neutron Lifetime Log* employs a pulsed electromechanical neutron source and a synchronously gated radiation detector. A prototype instrument has been field tested during recent months to demonstrate the operability of the apparatus and the feasibility of the method. Tests in wells and simulated boreholes have confirmed theoretical predictions and have shown that formation param ters can be measured independent of casing and other borehole parameters. Preliminary results of field tests have indicated that the log may have important and widespread applications. BASIC PRINCIPLE OF NEUTRON LIFETIME LOG The Neutron Lifetime Log is based on the fact that neutrons emitted by a source in a well are rapidly but not instantly captured by the material around the source. Their capture is a matter of statistical probability; the greater the number of capturing nuclei and the greater the "capture cross section", the greater is the probability that a neutron will be captured quickly. The average life of a thermal neutron in vacuum is about 13 minutes, but in common earth materials, the average neutron life ranges between extremes of about 5 rnicrosec for rock salt and perhaps 900 microsec for quartzite. The Neutron Lifetime Log responds to variations in this average neutron life. The theoretical basis for a log of this general type has been well understood by nuclear logging experts in many laboratories both in America and in Russia, and develop mental work along these lines has been in progress for many years. The Russian literature has reported both theoretical and experimental work1,2 but in this country there have been no published reports of progress toward a practical logging instrument. The logging instrument is designed to measure radiation produced by slow neutrons during selected intervals when no neutrons are being emitted by the source. The source is arranged to emit neutrons in bursts or pulses. During the quiescent interval between the pulses, it is possible to observe the exponential "decay" of the neutrons and the neutron-induced radiation as the individual neutrons progressively disappear due to capture by atoms in the formation or the borehole. When a short pulse of 14 mev neutrons is emitted by a source in a borehole, the individual neutrons are slowed to thermal energy within a few microsec. Thus, a cloud of "slow" neutrons is formed around the source within 10 to 50 microsec after the pulse. This cloud is most dense within a few inches of the source, and is progressively less dense out to a radius of about 3 ft, where radiation from the source is practically undetectable.

Jan 1, 1965

By John Chipman

Published data on the equilibria of carbon in binary Fe-C austenite with H2-CH4 and CO2-CO gas mixtures are used to obtain the constants of an equation repre -senting the activity coefficient of carbon throughout the stable austenite range of temperatutre mid compositiotl. Calculated values for the solubility of graphite are found to be in agreement with the best-published direct observations. Its heat of solution is 10,680 calper g-atom. The free energy of formation of cementite is culculated from the equilibrium compositions of austenite and of gas. Its entropy and heat of formation are also obtained. BASIC knowledge of the high-temperature properties and treatment of steels is contained in the Fe-C diagram and its extensions for the effects of alloying elements. The application of thermodynamics to the Fe-C system, with addition of alloying elements, can serve to simplify and systematize this knowledge. The points of beginning are the binary fee solution, austenite, concerning which our information is reasonably complete, and the binary carbide, cementite. Further studies must include the other phases of the binary system, a and liquid, and for these an accurate knowledge of the ? phase boundaries is essential. These studies should provide a firm base for systematic study of the effects of alloying elements on all phases of the system, their transformations, and precipitation phenomena. With the aid of the simplifying thermodynamic concepts of activity coefficients and interaction parameters it is to be hoped that the results of these studies will be amenable to computer solution thus making the information on multicomponent systems more readily available than would be possible in multidimensional diagrams. Studies of the thermodynamic properties of austenite have utilized equilibrium measurements on the reactions:

Jan 1, 1968

By Frederick M. Becket

DoctoR Albert Sauveur, distinguished scientist and Honorary Member of this Institute, predicted in the first Howe Memorial Lecture that the privilege of delivering' this annual address would be considered a highly significant honor. The intervening years have well borne out Sauveur's prophecy. I wish to assure the American Institute of Mining and Metallurgical Engineers that I also deeply appreciate this honor, recognizing at the same time the present and even more the future responsibilities with which it is accompanicd. Several of the previous lecturers had the good fortune to attend the classes of Professor Howc and to work in his laboratories. I was similarly favored, although in my instance and to my great regret the period was all too short. However, Howe's book, published in 1903, "Iron, Steel and Other Alloys," afforded me abundant opportunity to continue these studies. How well I remember the inspiration I derived from this famous book by Howe, the metallurgical master, pioneer, and educator! Remembering that Professor Howe contributed numerous papers to The Metallographist, a magazine supported from a technical point of view by the world's pioneers in metallography, I was curious a few days ago to learn the nature of Howe's early contributions to this magazine. The first paper by Howe in the first year of The Metallographist (1898) dealt with the allotropic theory; the second also treated of allotropy, and I quote the first sentence of that paper: The allotropic theory of the hardening of steel may, like so many other important theories, have to be accepted or rejected not on direct proof or disproof, but on the accumulation of circumstantial evidence for or against it. Howe's ability to stimulate others by his deep understanding and clarity of expression was truly remarkable; but just as striking was his intuitive judgment concerning the implications of metallurgical data in the arts and scienees. It therefore seems fitting that this lecture comprise a broad treatment of the subject chosen, rather than a closely documented thesis on any one phase of the problem; that in it attention be focused

Jan 1, 1938

By W. A. Ver Wiebe

UNder the impetus of new demands caused by the defense program, the oil and gas industries of Kansas established new records during the year 1941. In all, 2113 wells were drilled, which compares favorably with the record total drilled in 1937. These 2113 tests resulted in 1446 oil wells, 76 gas wells and 592 dry holes. In all three categories there was an increase over the previous year, but unfortunately the most marked increase was in the dry holes. Nearly 80 per cent of the increase must be allocated to the drilling 01 unsuccessful tests. This was partly because of the increasing difficulty of finding new reserve areas and partly because of the erratic character of the production in the Arbuckle dolomite, which is now the main producing zone. Closer analysis of the totals reveals that western Kansas accounted for 1634 tests, of which 1186 were oil wells, 34 were gas wells and 415 were dry holes. The total potential initial daily production uncovered by the successful wells amounted to 1,691,000 bbl. of oil and 508,000,000 cu. ft. of gas. Both figures indicate a considerable decrease when compared with the proceeding year; in 1940 the respective figures were 2,128,000 bbl. and 1,289,000,000 cu. feet. In eastern Kansas a total of 479 wells were drilled. Among these, 260 were oil wells accounting for a daily initial potential production of 45,662 bbl. The new gas wells numbered 42 and added 290,438,000 cu. ft. per day to the gas potential production of the state. The remaining tests, 177 in number, were dry. It is interesting and significant that almost half (791) of the total wells drilled in western Kansas were drilled by the independent operators. Among the large companies the Cities Service Oil Co. drilled 169 wells; the Stanolind Oil and Gas CO., 101; the Skelly Oil Co., 80; the Continental Oil Co., 99, and the Shell Petroleum Co., 63 wells. In eastern Kansas the independent operators drilled 406 out of the total of 479 wells. Among the major oil companies the Cities Service Oil Co. drilled 38; the Phillips Petroleum Co., 13, and the Sinclair-Prairie Oil Co., II wells. The figures on relative percentages of dry holes to successful oil or gas wells are revealing. In western Kansas approximately one third of all wells drilled by the independent operators were dry holes. The major oil companies drilled approximately 844 wells in western Kansas, of which 678 were successful in finding either oil or gas. It thus appears that the major companies fared much Getter than the independents. In eastern Kansas the major companies drilled 73 wells of which 63 were successful in finding commercial quantities of oil or gas. No less than 286 wildcat tests were put down in western Kansas and 72 in eastern Kansas, or 358 in all, during 1941. Considerably more than half of these were drilled by independent operators; zoo in western and 66 in eastern Kansas. An exploratory hole % mile or more from production is regarded as a wildcat well in Kansas. On a percentage basis, approximately 75 per cent of all wildcat wells were failures; only 25 per cent found oil or gas in western

Jan 1, 1942

By Robert Glass Cleland

[George B. Agnew Cleveland H. Dodge James Douglas E. Hayward Ferry Francis L. Hine Arthur Curtiss James1908-1941 1908-1926 1908-1918 1908-1935 1908-1927 1908-1941]

Jan 1, 1952

By D. F. Toner

THE decomposition of the ß phase in the copper-aluminum system has recently been subjected to considerable investigation1-4 As a result of this work, principally by Haynes, much additional interest has been aroused concerning the various transitional or metastable phases in the Cu-A1 system. No attempt has been made to resolve the question of whether the PI and ß" phases of Klier and Grymko5 are the same as the rosette-shaped phase first observed by Smith and Lindlief6 in 1933 during an isothermal transformation study of an eutectoid alloy. It is the purpose of this study, however, to obtain

Jan 1, 1960

By R. L. Huntington, D. T. MacRoberts, Charles R. Hetherington

Since the equation of continuity governing transient flow of gases through porous media cannot be integrated mathematically into a simple usable expression free from series terms, empirical and approximate equations have been advanced relating cumulative production and future production rates from gas reservoirs with time. In order to check the accuracy of these empirical equations and to obtain an insight into the initial conditions pertinent to the solution of the fundamental equation of continuity, experimental work has been conducted on a vertical 2-in. tube, 91.6 ft. high, packed with unconsolidated Wilcox sand. The results presented in graphical form show the accuracy of the approximate relations. Data from unsteady-flow runs on the 2-in. experimental tube are presented graphically, and are applied to obtain an equation for this specific case, and are offered as an aid in future investigations of this basic equation. The close agreement between equations calculated for steady-state flow and the experiments indicates that the decline of actual gas reservoirs may be treated by an application of these equations without serious error. Introduction The steady-state flow of gas through a porous material—that is, flow wherein the boundary conditions do not vary with time—is subject to analytical solution. Muskat1 has shown that the general differential equation is simply the La Place equation in P2. Direct solutions may be at once obtained. The unsteady state, on the other hand, is not analytically reducible. Since nearly all phenomena of practical interest in gas production involve flow in the unsteady rather than in the steady state, it has been necessary to derive approximate Solutions to the general equation. The validity of such approximations has not hitherto been adequately tested. In the experiments to be described a simple, closed, linear system is substituted for the real complex gas field. The general results, however, are independent of the geometry Of the system' The problem studied is the rate of production, and the accompanying variations in pressure, when one end of a linear porous system is opened to the atmosphere and permitted to produce to exhaustion. An approximate solution to the general differential equation, based upon the assumption of an "infinite series of steady states," is then applied to the results to determine the validity of this method of dealing with actual reservoirs. Theoretical Considerations The fundamental differential equation governing the flow of a gas through a Porous medium can be derived easily from the equation of continuity, Darcy's law, Boyle's law and a statement of the thermo-dynamic nature of the flow. For isothermal flow it is: d2P2/dx2 + d2p2/dy2 + d2p2/dz2 = 2fµ/K dP-dT

Jan 1, 1942

By N. S. Stoloff, R. C. Ku, R. G. Davies

The stress-strain behavior of Fe-Co and Fe- V alloys containing up to 25 pct solute have been studied in the temperature range 25° to - 196°C. The microyield stress is independent of temperature for all alloys studied, while the temperature dependence of the ordinary yield stress is large and comparable to that for unalloyed iron. An alloy-softening phenomenon is observed for many alloys relative to unalloyed iron, and appears to be a consequence of removal of inter-stitials from solution and their subsequent agglomeration. The ductile to brittle transition temperature is increased markedly by both cobalt and vanadium. Transmission electron microscopy observations reveal that cross slip and cell formation are restricted with increasing solute, which can account for many aspects of yielding and fracture behavior. IRON and other metals of bcc structure slip on many planes of the (111) zone at moderate and elevated temperatures, giving rise to wavy glide. At low temperatures, however, there is a tendency for slip to be restricted to planes of only one or two crystallographic types; in the case of Fe-Si alloys for example, (110) glide predominates, giving rise to planar slip bands."' Restriction of cross slip at low temperatures in iron has been linked by Brown and Ekvall3 to increased strain hardening in the preyield microstrain region, leading to an apparently large temperature dependence of the yield stress. Support for this view has been provided by Lawley and Gaigher4 from a transmission electron microscope study of molybdenum. They concluded that dislocations at lower temperatures, by virtue of their inability to change planes readily, are unable to interact and annihilate, leading to an increase in internal stress and work-hardening capacity. Restriction of cross slip at low temperatures has also been suggested to be an important factor in determining the ductile to brittle transition of single-phase solids, including metals of bcc structure.5 It is pertinent to note that most solute elements tend to raise the ductile to brittle transition temperature of poly crystalline ferrite,6,7 although in some cases, e.g., Fe-Cr7 and Fe-Al,8 the dilute alloys may actually yield at lower stresses than unalloyed iron. It appears, therefore, that solute elements may have an effect analogous to lowering the test temperature with regard to restricting cross glide. Such an effect has indeed been observed in the ionic alloy system KCl-KBr,9 in which bromine atoms, although causing little misfit and consequently little effect on the yield stress of KC1, have a pronounced effect in restricting wavy glide and inducing brittleness. The purpose of the present investigation was to determine the effects of selected solute atoms on the yield stress and fracture behavior of iron, and to elucidate in turn how the slip character was related to these properties. Since it is known that interstitial atoms exert a strong influence on the mechanical behavior of iron, the solute elements chosen for study were vanadium, which reacts strong with interstitials,10 and cobalt, which does not form highly stable interstitial compounds." EXPERIMENTAL PROCEDURE Four-pound ingots of each of the following alloys were vacuum-melted in zirconia crucibles: Fe-1, 5, 10, 25 at. pct Co, and Fe-1, 4, 10, 20 at. pct V. An ingot of unalloyed iron from the same original stock as that used for the alloy was remelted under similar conditions to eliminate variations in interstitial content arising from differing thermal histories. Chemical analyses of the iron, cobalt, and vanadium melt stock are listed in Table I. All ingots were rolled and swaged, commencing at 850°C, to 1/4-in.-diameter bar. The bars were then annealed at 850°C for 1 hr (except that the 10 and 20 pct V alloys were heated for 2 hr) to give a uniform equiaxed grain size of about 0.05 mm. Tensile samples of 0.125 in. diameter by 0.8 in. gage length were utilized for studies of the ductile to brittle transition. A second set of tensile samples were utilized for microstrain experiments in which strain sensitivity of 1 x 10"6 was achieved by a capacitance method.3 Cylindrical compression samples 0.250 in. diameter by 0.4 in. long also were prepared to study the influence of composition on the macroscopic yield stress, and for metallographic analyses of defor-

Jan 1, 1965

By R. E. Reed-Hill, W. H. Hartt

The second order, {1011}-{1012} twin bands observed in critically deformed magnesium are often accompanied by an unusual form of kinking. These kinks, which lie adjacent to and run more or less parallel to the twin band habit, allow plastic deformation that occurs inside the twins to be accommodated into the matrix. The bend planes of these kinks cannot be explained using slip dislocations with Burgers vectors lying in the basal plane. A mechanism involving a single set of {1012)(1011) dislocations is proposed to account for the kink band habit, in good agreement with the experimental observations. It has been shown that second order, {101l)-{1012} twinning is an important phenomenon for magnesium deformed in the ambient temperature range. A detailed study of these twins has recently led to a better understanding of their irrational habit plane1 and their relation to fracture in magnesium.' This paper is concerned with a third aspect of these twins; this being the kink bands, originally referred to as shear accommodation kinks,3'4 that are often induced in the adjacent matrix. A twin band and its shear accommodation kink usually appear as a single macroscopic deformation, as seen in Fig. 1. The complex nature of these deformed regions is easily revealed, however, with the aid of a suitable microscope. It has been proposed374 that the primary function of these kinks is to accommodate the nonhomogeneous deformation that normally occurs in the second order twins. The twins tend to form as small discrete lamellae lined up approximately one in front of the other.''' Very large plastic deformations varying in magnitude from one twin to the next, may occur inside these lamellae. The kinks serve both to pass this strain into the matrix and to accommodate strain variations between twins. Deformation within the kinks, subsequent to their formation, has also been observed;3,4 and it is thought that this contributes to the strain accommodation process. The bend planes of the kinks have a habit near that of the twin band itself, which lies about 56 deg from the matrix basal plane. This orientation does not bisect the angle formed between the basal plane to either side of the bend plane and therefore differs markedly from the kink structure usually observed in hcp metals.'-' The present paper reports the results of a study of shear accommodation kinks and proposes a possible solution to the problem of the orientation of the bend plane. EXPERIMENTAL PROCEDURE Rectangular cross-section tensile specimens with axes parallel to (1010) and faces to (1210) and (0001) were cut and acid machined from a high-purity magnesium single crystal. After straining on an Instron machine the specimens were examined by both optical and replica electron microscopy. The basic procedures have been previously reported."' EXPERIMENTAL RESULTS AND DISCUSSION Structure of Shear Accommodation Kinks. A typical, large (101l)-{1012) twin band with its associated shear accommodation kink is shown running diagonally from upper left to lower right in Fig. 1. In this optical micrograph the twin band, consisting of a row of small, highly deformed twin lamellae, is visible as a narrow dark band along the left hand edge of the structure in question. The kink lies to the right of the twins, is approximately three times as wide, and is lighter in contrast. The horizontal slip lines visible on the general specimen surface correspond to matrix basal slip and are parallel to the tensile axis. Note that on the right-hand side of the band these slip lines can be followed from the matrix into the kink. At the kink band boundary the slip lines suffer a clockwise rotation of about 25 deg. Rotations of this magnitude are not uncommon. When a surface such as that in Fig. 1 is given an etch1 making it sensitive to polarized light, it has been observed that the slip traces in the kink are parallel to the basal plane trace in this region. This is in excellent agreement with the assumption that these regions are indeed kinks. Fig. 2 is an electron micrograph of this same twin band and kink. Note that a row of small supplimation pits has formed

Jan 1, 1969

By Yoginder P. Chugh

Elastic and viscoelastic behavior of three rocks-Tennessee sandstone, Barre granite, and Indiana limestone-was studied experimentally under uniaxial tensile stress. Cylindrical specimens of these rocks, about 1.0 in. diam and 2.0 in. long, were subjected to incremental constant stress history under uniaxial tension. The stress was held constant for a period of 40 min at each stress level. During this period, longitudinal and transverse strains on specimens were continuously monitored. The straintime history at each stress level was analyzed for elastic and viscoelastic parameters of a generalized Burger model. The viscoelastic parameters under uniaxial tensile stress were compared with those under uniaxial compressive stress. The experimental setup, experimental procedure, analysis techniques, and more significant results are described. This limited research effort clearly indicates the importance of the mechanical behavior of geologic material under tensile stresses.

Jan 1, 1975

C. W. GOODALE,* Butte, Mont.-I notice Mr. Newton refers very briefly to the carbonate ores of manganese, rhodochrosite, but he does not go into any special description of the treatment of that material. In some of the veins in Butte, Mont., there is a large amount of rhodo-chrosite, and a large tonnage of that material has been shipped to the East for making ferromanganese. At the works of the Anaconda company at Great Falls they treated several thousand tons of this manganese ore, running about 37 to 38 per cent. manganese, in electric furnaces, giving a product of about 78 per cent. of manganese. But just at that time the demand for ferromanganese from the West was discontinued and the material, about 1000 tons of 78 per cent. manganese, is on hand at the works at Great Falls. With the higher-grade manganese ore, running, we will say, 37 or 38 per cent., there are large bodies of ore perhaps 20 or 25 per cent., but containing too much silica to be valuable in their present condition. Some efforts have been made for water concentration of that material, but owing to. there being only a difference of about 1 in the specific gravity of the quartz gangue and the manganese mineral, water concentration has offered some difficulties, I have been told, however, that some very satisfactory experiments have been made with magnetic concentration of this material. I think it is a new idea that this manganese ore can be treated successfully by magnetic concentration.

Jan 4, 1919

By T. C. Clarke

The history of iron construction in this country well illustrates the three phases of thought described by Auguste Comte, the French philosopher. The first is the era of faith, when belief in the safety of structures rests on the authority of the designer. The second is the era of criticism, when plans of structures are analyzed with much mathematical skill, but the data upon which the chain of reasoning depends is assumed upon insufficient experiment. The third, upon which we are now entering, is a scientific era, which demands experimental proof. It also demands that this proof shall be derived from experiments made on full-sized specimens, such as are in actual use, and not upon toy models. Until the construction of the United States testing-machine, now at Watertown Arsenal, it was impossible to make such experiments with accuracy. We now have a machine in which we can test full-sized specimens of every part of a bridge or other structure that we want to use, and under the same conditions in which it is actually used. The next thing is to get money to make these experiments available. No private individuals can afford to do it, and even if they could, they might wish to keep the results to themselves. So that the next point is that we want money, and that, I believe, everybodly thinks we should ask Congress for. We want also, as has been said, some one who shall make a business of testing, and who has plenty of time. Persons who are employed in private business are too much in a hurry; they want to do a thing and get done with it, and then do something else; but government officers are entirely free from this feeling; time to them is of no account, and in experimenting that is the very element that is of value; it does not do to be hurried; the great thing is to get it right and to test your results, and go over it, again and again. And the experimenter who operates the machine must be some person educated up to the use of it. We then want a general advisory board who will indicate a plan of experiments, collect the results; and publish them. Some experiments were made the other day at the Watertown Arsenal upon full-sized

Jan 1, 1882

By W. H. Bassett

ALTHOUGH brasses and bronzes have been made for ages, a systematic study of their physical properties has been carried out only during the years of the present century. Among these properties may be included those which are to be detected by means of microscopic examination; in other words by the science of metallography. The earlier workers in this field, both in this country and abroad, gave their attention to steel. When the senior author explored the situation in 1902, there was little encouragement to be found in undertaking the study of the non-ferrous alloys. A start was made, and the metallography of the brasses and bronzes, as well as of the copper-nickel- zinc alloys developed materially under his direction. Annealing experiments were begun in 1902, and in the succeeding years the effect of temperature, and the influence of previous working, on the grain size of brass were studied. The conclusions so well known and widely published today were largely reached during those earlier years. In 1905 the first complete annealing series were made. By this it is meant that brass and copper sheet, 5 B & S Nos. hard, was machined into tensile test specimens, then annealed under accurate control for 30 min. at temperatures up to the melting point of the material. Various determinations were made, including tensile strength and elongation in 2 in. There rapidly followed similar series on all of the copper-zinc alloys from 100 to 60 per cent. copper, on the bronzes, cupronickels, and on copper-zinc-nickel alloys. At this point there was published by Grard, in October, 1909,1 the very comprehensive and complete work on the tensile properties of cartridge brass, 90-10 copper-zinc, and electrolytic copper. The excellent photomicrographs in that paper illustrated the changes in structure produced by cold rolling as well as by annealing at different temperatures, but where Grard's work was confined to copper and to two alloys, the investigations in this laboratory have been over the entire fields of the commercial copper-zinc alloys, copper-tin alloys, representative copper-nickel and copper-nickel-zinc alloys as well as aluminum bronzes and others of a more special nature.

Jan 1, 1927

By Nick A. Hasenack, Heinz Kister, Rolf B. Vogel, Kees H. van Toor

A full survey of the laboratory and blast furnace tests carried out on two types of acid pellets is given. From the lab tests it appears that type B has a better low temperature disintegration index and a lower reducibility index than type A. The chemical composition and swelling indexes do not differ for both types. From the blast furnace test periods, carried out with a charge of 45% of pellets and 45% of sinter, it follows that both types of pellets lead to the same pig-iron production, blast furnace permeability, and blast furnace dust production. It also can be concluded that type B pellets cause a significantly higher coke consumption.

Jan 1, 1977

By L. T. Larson

The spectral reflectivity of zirconium in light of 441 to 668 nanometers (nm) wavelengths and air immersion has been determined. Bireflectance and apparent-angle -of-rotation measurements show zirconium to be optically isotropic when examined in light of approximately 484 nm wavelength. There is a direct relationship between bireflectance and the tilt of the basal pole of zirconium from the surface normal. This relationship allows the determination of the spatial orientation of the basal pole of an individual single crystal within a coarse-grained poly crystalline section to within± 2 to 3 deg for angles of basal pole tilt from 0 to 90 deg. In recent years considerable attention has been given to the quantitative determination of optical properties of opaque minerals by use of vertically incident, plane-polarized light. In particular, Cameron' and Cameron et a1.2 have developed criteria for the identification of a large number of anisotropic ore minerals based upon measurement of the apparent angle of rotation and the ellipticity or phase difference of the reflected light. It was shown by Larson and Pickle-simer3 that apparent-angle-of-rotation measurements may also be used to determine crystallographic orientations of grains of noncubic metals. In particular, it was shown that the basa.1 pole orientation in space of zirconium grains can be determined to ±3 deg for those grains with basal pole tilts of 10 to 90 deg from the plane of the section. Another, even more widely studied, optical property is reflectivity. cameron4 has commented upon measurement of the reflectance of plane-polarized, vertically incident light and Bowie and Taylor5 have made such measurements an integral part of their system of ore-mineral identification. Leow6 has reported on the spectral reflectivity of molybdenite and has used reflectivity values to calculate refractive indices and absorption coefficients. Cameron7 has made use of reflectivity values to ascertain aniso-tropic ore mineral symmetry and Piller and v. Gehlen8 have evaluated sources and importance of errors in reflectivity measurements as applied to calculation of optical constants. cambon9 has shown that reflectivity measurements using vertically incident, plane-polarized light are useful in the investigation of metals and in the identification of phases present in alloys. Bronson10 has made preliminary measurements on the optical anisotropy of beryIlium and Mott and Haines11 have published qualitative data on the intensity of light reflected from sections of bismuth, tin, and aluminum when these metals are microscopically examined under crossed polarizing plates. Koritnig12 has correlated the reflectivity of homogeneous solid solutions with their chemical compositions. From the above work and investigations in progress by this author, it is apparent that accurately determined values for the reflectance of vertically incident, plane-polarized monochromatic light from carefully polished surfaces of noncubic metals can prove useful in identification, composition determinations, and crystallographic orientation applications. Finally, reflectivity values, when measured in two media of differing refraction index and related to standards whose spectral reflectivities in these media are known, can be used to calculate optical constants such as refractive index and absorption coefficient. These constants may prove of use to those concerned with problems of electron band configuration. This paper reports the spectral reflectivity of zirconium measured in light of 441 to 668 nanometers (nm) wavelengths and air immersion. It also gives maximum bireflectance values for a prism section of zirconium in these wavelengths and shows how bire-flectance may be used to determine the crystallographic orientation of zirconium single crystals. Because of the lack of information on the reflectivities of the standards in oil immersion, no attempt is made to calculate the refractive indices or absorption coefficients although it is recognized that such values may be of fundamental importance. METHOD Single crystals of zirconium were cut by electro-discharge machining from a single-crystal rod grown from iodide bar by an electron-beam zone-melting process.13 The crystal sections were mounted in cold-setting epoxy resin and mechanically polished to a plane, uniform, bright surface. Each crystal was then chemically polished in a 26/26/43/5 mixture (by vol) of water, nitric, lactic, and hydrofluoric acids to remove the mechanically damaged and smeared surface layer. Final polish was obtained by electropolishing at 30 v in a bath of methyl alcohol and perchloric acid (98/2 by vol) at -70oc.14 Reflectivity measurements were made using a photometer system designed and developed at Oak Ridge National Laboratory and described in detail by Larson.15 Briefly, the reflectivity measuring system consists of a reflecting microscope; a double-beam, null-balancing photometer array; a mechanically driven microscope stage; and a direct X-Y readout of the reflectivity of the specimen relative to its orientation on the microscope stage. The measuring photometer receives its signal from the specimen through a slotted Wright occular placed on top of the photovisual head of the microscope. The reference photometer receives light through a flexible glass "light pipe" from a mirror in the reflecting system of the microscope. Monochromatic light is attained through use of interference filters (15-nm half-peak width pass bands) placed in front of a stabilized Vickers 12 v, 100 w, tungsten-filament, quartz-iodide lamp.

Jan 1, 1970

By James H. Courtright, Kenyon Richard

TOQUEPALA is a porphyry copper deposit in which mineralization is localized by a large breccia pipe formed in dose genetic relation to intrusive rocks. The deposit is in southern Peru, 55 airline miles north of the small city of Tacna and the same distance inland from the port of 110. Quellaveco and Cuajone, geologically similar deposits, lie 12 and 19 miles north of Toquepala. Chuquicamata is 400 miles to the south. The deposit is high on the southwestern slope about 20 miles from the crest of the Cordillera Occidental of the Andes Chain. It lies in a mountainous desert where the steep southwesterly slope of the Andes is dissected by a succession of rapidly downcutting, deep canyons. Local topography is moderately rugged with a dendritic drainage pattern and an elevation of 8000 to 14,000 ft. Volcanic peaks along the crest of the Cordillera rise over 19,000 ft.

Jan 2, 1958