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By D. A. Dahlstrom

Although the liquid-solid cyclone is a relatively recent innovation in the field of coal preparation, various authors have already indicated three distinct applications to operations encountered in the modern tipple. Driessen's articles and work at the Dutch State Mines exhibited its possibilities in the bene-ficiation of fine coal with apparently high efficiencies down to the 200-mesh fraction. l,2,3,4 Other publications point out its use as a recoverer, thickener, and preliminary dewatering agent of fine coal which in too many cases is being wasted due largely to former high operating cost limitations.M Finally, certain authors have emphasized the practicability of applying the cyclone to the elimination of coarse and fine solids from water slurries in the tipple in order to produce a water suitable for recycle purposes containing only minute particles far below the 200-mesh size.6 This would result in a closed water system for many cases, with its accompanying economic and operating advantages to locations where water quantity and quality problems are severe; better operation of washing equipment using a consistent water devoid of injurious fine particles; lowered maintenance costs due to the lesser abrasion resulting when the fine abraiding particles are removed; and the greater ease of disposing of refuse streams of reduced volume containing greater percentages of solids. While the three applications have been indicated to be feasible, only a meager amount of data is available on capacities and solid elimination eficiency as a function of design variables and cyclone friction loss. This information is essential for the optimum use and construction of the solid-liquid cyclone, and accordingly, work on the problem was initiated at Northwestern University. For the unfamiliar reader, briefly the cyclone consists of a cylindrical section mounted above a truncated cone. The feed nozzle enters the cylindrical ring tangentially with the underflow nozzle permitting discharge of the concentrated solids located at the apex of the cone. The overflow nozzle through which the clarified water exits is centered in the cylindrical section at the top of the cyclone. Half sections of experimental cyclones will be found in Fig la and 6. The feed slurry enters with a tangential velocity, thus creating a spiral pattern of high centrifugal force. The solid particles of sufficient size and gravity are ejected outward to the walls and spirally discharge to the underflow. Most of the water with uneliminated fine solids moves radially inward along the path of the outer

Jan 1, 1950

By W. L. Chu

It was observed that chromized coatings on low carbon steel could be embrittled by cooling slowly through the 475°C range. A higher chromium coating was more susceptible to embrittlement than a lower chromium coating. Coating structure and composition could be correlated with the chromizing process and prior carbon content of the steel. IT was recently observed that during the fabrication of rectangular tubings made with chromized thin gage 1010 steel, a high percentage of these parts were fractured readily in a brittle manner under the light impact-forming load employed. Ensuing investigation indicated the cause for such brittle failures to be the so-called 475°C embrittlement of the chromized coatings. The experimental work and results are briefly reported. Rectangular tube sections of normalized AISI C1010 steel, which had a cross-section of 0.5x1.5 in. and a wall thickness of 0.030 in., were chromized to yield coatings having several ranges of thickness, varying from 0.0005 to 0.002 in. Essentially, the chromizing process is similar to that described by Samuel and Lockington,' which consists of heating the parts in a sealed container at about 955°C for 4 hr in intimate contact with a chromizing mixture* samples in a hydraulic press, and the other employed a simple beam bending test of the flat sides of the tubing walls. Neither, however, was able to differentiate the relative brittleness of samples known to include both the brittle and tough types, since the impact-brittle samples were found to deform readily in a manner similar to the tough ones. Both the tough and brittle samples were studied by reflection microscopy. Observation showed that the microstructures of the steel cores were similar in content and distribution of inclusions as well as in the ferritic grain size. Results of Filar micrometer measurements showed that coating thicknesses+ of the brittle samples averaged 0.0007 in., whereas those of the tough samples averaged 0.0016 in. The micrographs of Fig. 2 illustrate the structural differences between coatings of both types of samples. By dissolving the steel cores in nitric acid, coatings of both the brittle and tough samples were isolated. Simple bending tests showed that coatings of the brittle samples cracked readily at about 90" bend, whereas those of the tough samples could be bent nearly 180° without cracking. The coatings as well as the steel cores were analyzed for carbon and

Jan 1, 1956

By L. G. Sprague

The fact that this latest and most modern of the Universal Atlas Cement Company's plants at Northampton, Pa., is the fifth to be built on these same properties, and their development has been coincidental with the development of the portland cement industry in the United States, makes it appropriate to sketch briefly the history of the successive steps. In 1889 the original Atlas Portland Cement Co. started its first plant at Coplay, Pa., which is just across the Lehigh River from the present operation. Here the first successful rotary kiln was operated. These kilns were 6 ft. in diameter and 60 ft. long; they used oil for fuel until 1895, when the company developed the first burner for pulverized coal. Shortly thereafter the Atlas company acquired property on the Northampton side of the river and built its plants Nos. 2, 3 and 4 within the following 10 years. During the same period the production of portland cement in the country was increasing rapidly; owing largely to the development of the rotary kiln and improved grinding machinery, which lowered the cost and improved the quality of cement. The general tendency has been to increase the length of the kiln and grind both raw material and finished product Liner. In 1930 the Atlas Portland Cement Co. and the Universal Portland Cement Co. united to form the Universal Atlas Cement Co., and the same policy of improving the product has been continued. Because of the large amount of research carried on by manufacturers and consumers, including government agencies, there is a demand for cement of different chemical and physical characteristics for different kinds of structures. Hence many engineers in recent years have been asking for cements of certain definite chemical analyses, which they think are best for their particular jobs. This has compelled the manufacturer to make several different types of cement by variations of chemical composition. These are generally made by adding silica, iron and lime to the standard mixture, which necessarily increases the cost of the product. Therefore the Universal Atlas Cement Co., in planning the modernization of its Northampton plant, gave this particular phase of the problem considerable study. Research and experimentation have developed the practicability of making a wide variety of differently proportioned raw materials for cement by a process of subtraction rather than by addition. With such process, it is possible to discard the undesirable aluminates and silicates from the ample supply of impure limestone available from the company's property rather than by adding high-grade limestone obtained from distant sources. This procedure requires mineral separation by centrifugal sedimentation and froth flotation. Since the chemical and mineral constituents of Lehigh Valley "cement rock," together with the methods of separating them, have been thoroughly described in published

Jan 1, 1948

By L. G. Sprague

The fact that this latest and most modern of the Universal Atlas Cement Company's plants at Northampton, Pa., is the fifth to be built on these same properties, and their development has been coincidental with the development of the portland cement industry in the United States, makes it appropriate to sketch briefly the history of the successive steps. In 1889 the original Atlas Portland Cement Co. started its first plant at Coplay, Pa., which is just across the Lehigh River from the present operation. Here the first successful rotary kiln was operated. These kilns were 6 ft. in diameter and 60 ft. long; they used oil for fuel until 1895, when the company developed the first burner for pulverized coal. Shortly thereafter the Atlas company acquired property on the Northampton side of the river and built its plants Nos. 2, 3 and 4 within the following 10 years. During the same period the production of portland cement in the country was increasing rapidly; owing largely to the development of the rotary kiln and improved grinding machinery, which lowered the cost and improved the quality of cement. The general tendency has been to increase the length of the kiln and grind both raw material and finished product Liner. In 1930 the Atlas Portland Cement Co. and the Universal Portland Cement Co. united to form the Universal Atlas Cement Co., and the same policy of improving the product has been continued. Because of the large amount of research carried on by manufacturers and consumers, including government agencies, there is a demand for cement of different chemical and physical characteristics for different kinds of structures. Hence many engineers in recent years have been asking for cements of certain definite chemical analyses, which they think are best for their particular jobs. This has compelled the manufacturer to make several different types of cement by variations of chemical composition. These are generally made by adding silica, iron and lime to the standard mixture, which necessarily increases the cost of the product. Therefore the Universal Atlas Cement Co., in planning the modernization of its Northampton plant, gave this particular phase of the problem considerable study. Research and experimentation have developed the practicability of making a wide variety of differently proportioned raw materials for cement by a process of subtraction rather than by addition. With such process, it is possible to discard the undesirable aluminates and silicates from the ample supply of impure limestone available from the company's property rather than by adding high-grade limestone obtained from distant sources. This procedure requires mineral separation by centrifugal sedimentation and froth flotation. Since the chemical and mineral constituents of Lehigh Valley "cement rock," together with the methods of separating them, have been thoroughly described in published

Jan 1, 1948

By Walter Miller

With returning prosperous conditions in all industries, oil-refinery engineering has found opportunity for the more extensive application of improvements developed during the several years of depression. The year has brought out little of an entirely new nature, but much in wider application of previous worth-while developments. The greatest volume of work done has been in modernizing the distillation and cracking units of existing refineries, particularly by substitution of combination skimming and cracking units for older equipment, and the installation of cracking plants in smaller refineries where formerly only skimming was practiced. A number of entirely new refineries were installed during the year, two of the most important being the 20,000-bbl. refinery by the Atlantic Refining Co., at Atreco, Tex., and a 12,000-bbl. plant by the Wilshire Oil Co., at Norwalk, Calif., these two embodying some of the latest developments in cracking and treating. Total refining capacity for the United States is now reported as being something over 4,000,000 bbl. per day, but a movement is on foot looking to a complete revision of these figures, as experience has indicated not only some overstatement of capacity of equipment but that considerable equipment is included which because of obsolescence and location will probably never be run again. The 3,000,000-bbl. figure which the industry reached during the year's high consuming period required the operation of probably 95 per cent of the country's efficiently usable capacity. Cracking and Polymerization There were no new outstanding developments in the cracking field, progress being made largely in the further refinement of known principles. Improvements in furnace design and operation have been largely in permitting closer control of the heating curve through the cracking-tube system, assisting in more uniform yield and in the lessening of coke deposition, and permitting longer trouble-free operating time as well as reduction in furnace-maintenance cost. Actual operating polymerization capacity has been increased little during the year, but a number of projects have been started, some nearing completion, the production from which will be available during 1937.

Jan 1, 1937

By R. Schuhmann, G. W. Powell

The concept of local equilibrium is examined and, in particular, the applicability of the concept to two-phase binary diffusion couples is discussed. It is concluded that, if binary solid solutions are treated thermodynamically as ternary solutions, vacancies being the third component, then recent experimental observations of nonequilibrium interface compositions (i.e., compositions different from the phase diagram values) are consistent with a state of complete dynamic equilibrium at the interface. CLASSICAL approaches to diffusion and to other irreversible processes often utilize a postulate of "local equilibrium". That is, one assumes even in the presence of gradients, fluxes, and time changes of properties, a) that the Second Law can be formulated locally, and b) that thermodynamic equations of state among intensive properties are identical with those for equilibrium phases. A direct consequence of this assumption, for example, is that one would calculate the total entropy of a nonequilibrium phase simply by integrating the entropy density (eu per unit volume) over the volume of the phase, assuming that entropy density is the same function of energy and particle density as for equilibrium phases. In the study of diffusion and of diffusion-controlled phase transformations, metallurgists take this concept of local equilibrium for granted and utilize it automatically. In fact, experimental evidence of all kinds is overwhelming that "local equilibrium" is a valid limiting law, approached more and more closely as gradients and rates of change approach zero. On the other hand, we have neither experimental nor statistical thermodynamic proof that this principle of "local equilibrium" should remain rigorously valid at high gradients and for rapid processes. Theoretically, in fact, one would expect deviations because interactions between adjacent volume increments of material affect the evaluation of entropy. Also one observes experimentally structural and small energetic differences between equilibrium and nonequilibrium phases. The purpose of this paper is to present a thermodynamic framework for the study and correlation of deviations from strict local equilibrium in isothermal diffusion and related processes. This procedure, in effect, preserves the principle of local equilibrium by thermodynamically assigning the deviations from static equilibrium properties to a defect component. Although this theory is entirely phenomenological, the possibility does exist of correlating the theory with experimental observations of defects under favorable circumstances. The most immediate application appears to be to the equilibria at the interfaces in two-phase binary diffusion couples. A recent pertinent work by Eifert et al.1 has shown that the concentrations of aluminum in the a(fcc) and B(bcc) phases at the 0-8 interface in Cu:Cu-12.5 wt pct A1 diffusion couples are greater than those given by the phase diagram. It is postulated by these authors that the supersaturation of the o phase at the interface provides the driving force for the a-to-B lattice transformation; the excess free energy of the a phase, ?Gaxs, arising from the greater-than-equilibrium aluminum concentration is about 3 cal per g-atom. On the basis of the schematic free energy-composition diagram shown in Fig. 1, Eifert et al. concluded that the thermodynamic situation at the interface is one of the partial equilibrium; that is, = for the more mobile aluminum whereas will be reexamined in the latter part of this paper. THERMODYNAMIC PROPERTIES OF DEFECTS A rigorous analysis of the thermodynamics of defects requires an added degree of freedom in the Phase Rule sense, because the standard formulations of solution thermodynamics (partial molal properties of components, free energy minimization, equality of chemical potentials, and so forth) involve the implicit

Jan 1, 1970

[RALPH ADAIR Ore Dressing Consultant Bull Mtn. Rd., Asheville, N. C. Phone 4-1693 JAMES A. BARR Consulting Engineer Mt. Pleasant, Tennessee Washington, D.C. BEHRE DOLBEAR & COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4, N. Y. I. B. BERENT Engineering Consultants and Contractors Mineral Exploration, Mine Evaluation, Mine Designs and Mine Management 158, Ataturk Bulvari-Ankara, Turkey BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 8 Howard-Canfleld Bldg. Santa Barbara, Calif. COWIN & CO. Mining Engineers and Contractors Consulting Shaft & Slope Sinking Appraisal Mine Development Reports Mine Plant Construction 1-18th St. S. W. B'ham, Ala., Phone 56-5566]

Jan 1, 1952

By S. J. M. van Leeuwen, R. Feenstra

The effect of jets on bit penetration has been investigated by means of a 50-ton drilling machine and 8½-in. commercial jet bits, drilling under representative bottom-hole conditions. The conclusions apply to the drilling of impermeable rock only. Penetration rate is in all cases primarily hampered by a differential pressure effect, known as dynamic hold-down. Jet action can reduce this slightly. Major gain in penetration rate, up to 25 or 50 per cent, is already ohtained at medium-high jet power. At high bit load, penetration by soft to medium-hard-formation bits is further hampered by bit-balling. Its alleviation requires intensive tooth scavenging, which is best performed by slanted nozzles with trailing, high-velocity, high-volume jets, hitting bottom in front of the teeth. Penetration may then improve by a 100 per cent. At high bit load, bottom-balling limits the penetration of insert-type bits. In this case bottom scavenging is required, which is most effectively performed with high velocity jets from nozzles extended close to bottom. As a result of this measure, penetration may improve 70 per cent in non-friable rock, and less in friable rock. This will make the insert-type bit more versatile. Toothed hard-formation hits suffer at high bit load from both bit- and bottom-balling. Slanted nozzles, possibly much extended, with high-velocity, high-volume jets then have best prospects. INTRODUCTION For years the use of jet bits in oil well drilling has been increasing, in conjunction with ever greater hydraulic horsepower. To the same extent, the need for efficient use of the horsepower has grown.' This paper, it is hoped, will contribute to an understanding of how effective jet action may be obtained. It deals with the effect of jets on phenomena that are known' " to hamper bit penetration. To study this effect, laboratory drilling tests were performed with 8½-in. commercial bits under bottom-hole pressures representative of deep wells. The investigation has been restricted to the drilling of practically impermeable rock. In the following sections, the increase in bit penetration rates due to jetting is discussed for conditions which made the troublesome phenomena stand out one at a time. A brief definition and interpretation of these phenomena is given in Appendix A. Appendix B gives the results of measurements of fluid velocities along the hole bottom, performed in stationary flow tests. Descriptions of equipment, bits, rocks and mud are collected in Appendix C. Unless otherwise mentioned, drilling conditions were kept standard as given in Table 1. CUTTING TRANSPORT TO THE ANNULUS Jet action was for some time believed to merely improve the transport of cuttings from bottom to annulus, resulting in a clean hole bottom. Flow tests performed in 1954 at the Battelle Memorial Institute6 showed, however, that jet velocities of the order of 40 ft/sec sufficed to clear even large (0.4-in.) chips from bottom in the time between two successive tooth actions. In the field, optimum jet velocities are appreciably higher, indicating that other effects must be involved. This much is confirmed by the results of our drilling experiments in soft rocks performed under atmospheric pressure, i.e., in absence of pressure-differential effects. Fig. 1 shows that variation in the nozzle velocity from 40 to 330 ft/sec had no effect on penetration rate, unless the bit penetrated more than 7 mm per revolution, which is about half the tooth height. At such high rates—150 ft/hr at 100 rpm—cuttings would be caught in the tooth cavities, leading to bit-balling, which was noticed on inspection of the bit. The jets thus assisted in keeping the tooth cavities clean. This is just perceptibly reflected in the penetration-rate curves of Fig. 1: Much the same results were obtained in hard rocks with hard-formation three-cone bits. The conclusion is that transport of loose cuttings towards the annulus does not require a powerful jet action. In the following sections we shall see that in deep-well drilling other phenomena are of greater importance. DYNAMIC HOLD-DOWN It is generally accepted that, in deep-well drilling, bit penetration is hampered primarily by the existence of a difference in pressure between the fluid in the hole and that in the rock at the depth of cutting.2-5 In the drilling

Jan 1, 1965

By E. A. Calnan, B. E. Williams

IN the development of a new treatment for the prediction of deformation textures,'-' it was noted that for no metals are there experimentally determined tension textures with which the predictions may be compared. There is a considerable knowledge of drawing textures and previous workers have been content to consider these as equivalent to tension textures for the purposes of comparison. It is shown, however, in the new treatment that the tension and drawing textures are not necessarily identical, the radial compression exerted by the dies in the drawing operation producing some modification of the tension texture. In particular for the face-centered cubic metals it is predicted that for drawing the final texture should be [1ll] with a spread towards [211] (a more detailed derivation of this texture has been made by Calnan3). This has been amply confirmed by experiment, see Hibbard.6 For the pure tension case, however, the treatment predicts intermediate [1ll] and [loo] textures leading to a [211] end-point, while all previous treatments have predicted the final texture as [1ll] with in some cases an additional [loo] component. Thus evidence that the pure tension end-point is the [211], or at least that [1ll] and [l00] are not the final textures, should provide a valuable test of the new treatment. Accordingly some experiments were made on aluminum. Three aluminum specimens were examined in detail, one of cold-rolled high purity rod (99.99 pct), specimen A, and two of commercial extruded rod of purity 99.4 pct, specimens B and C. The initial annealing treatments were: A, 1½ hr at 400°C; B, 2 hr at 400°C; C, 1½ hr at 650°C. The principal difficulty is that of obtaining sufficient elongation before fracture occurs. This was overcome to some extent by giving a softening heat treatment, 1 hr at 300°C, after each 15 pct of extension. Vickers hardness measurements gave values before and after the softening treatment of about 30 and 28, respectively, in comparison with the initial value of about 19 corresponding to fully annealed material. From recent observations in this laboratory it is concluded that this small recovery corresponds to a polygonization process rather than recrystallization proper and consequently the preferred orientation is unaffected. At the higher extensions, however, some slight necking of the specimens took place and it was necessary to turn them down to a uniform cross-section before

Jan 1, 1953

By Harrison Schmitt

The definitions of the terms commonly used in connection with metamorphism at elevated temperature near igneous contacts are re-examined. As the study of tactite zones associated with igneous contacts progresses, more and more emphasis is put on the localization of the ore by structural forms. The generally early age of the silicates and late age of the sulphides is well established. Postsilicate structural deformation is likely to localize ore bodies. The silicates are often replaced by the ore minerals. we may not be far from proving that the elements involved in the formation of silicate aureoles are merely normal "volcanic" emanations, that silica, lime, magnesia, and alumina, and probably soda and potash, are likely to undergo local transfers only. The work of Newhouse suggests the agents of the formation of sulphides in deposits of various classifications are the volcanic emanations. Introduction The purpose of this paper is to define the terms commonly used in connection with the subject, to briefly review and discuss the broad features of the aureoles, to indicate some of the features lately recognized: to discuss the genesis, and to suggest how the associated ore deposits can best be studied and developed. When developing a subject in mining geology one is soon conscious of the vast amount of pertinent literature and that most relevant ideas, no matter how obscure, have been considered. One can only hope to make some small contribution in point of view, a few confirmatory observations, or, perhaps, suggest a small new idea indebted to the most recent data. It is nearly impossible, also, to give specific credit, and adequate credit, to all the contributors to a given subject. This study, furthermore, was not intended to cover the field exhaustively, nor is the bibliography complete. Definition OF Terms There is much confusion in the use of the broad terms concerned. Needless to say, metamorphism means change of form; metasomatism, change of substance. The term contact metamorphism, however, has been widely misused possibly by a majority of economic geologists and engineers. As originally adopted by European investigators it meant changes effected largely by heat (thermal effects) in the rocks invaded by plutonic intrusives, but did not include those local changes usually at the immediate contact brought about by the addition of substance, i.e., by metasomatism. The term has become clouded. In Europe it has

Jan 1, 1949

By Harrison Schmitt

The definitions of the terms commonly used in connection with metamorphism at elevated temperature near igneous contacts are re-examined. As the study of tactite zones associated with igneous contacts progresses, more and more emphasis is put on the localization of the ore by structural forms. The generally early age of the silicates and late age of the sulphides is well established. Postsilicate structural deformation is likely to localize ore bodies. The silicates are often replaced by the ore minerals. we may not be far from proving that the elements involved in the formation of silicate aureoles are merely normal "volcanic" emanations, that silica, lime, magnesia, and alumina, and probably soda and potash, are likely to undergo local transfers only. The work of Newhouse suggests the agents of the formation of sulphides in deposits of various classifications are the volcanic emanations. Introduction The purpose of this paper is to define the terms commonly used in connection with the subject, to briefly review and discuss the broad features of the aureoles, to indicate some of the features lately recognized: to discuss the genesis, and to suggest how the associated ore deposits can best be studied and developed. When developing a subject in mining geology one is soon conscious of the vast amount of pertinent literature and that most relevant ideas, no matter how obscure, have been considered. One can only hope to make some small contribution in point of view, a few confirmatory observations, or, perhaps, suggest a small new idea indebted to the most recent data. It is nearly impossible, also, to give specific credit, and adequate credit, to all the contributors to a given subject. This study, furthermore, was not intended to cover the field exhaustively, nor is the bibliography complete. Definition OF Terms There is much confusion in the use of the broad terms concerned. Needless to say, metamorphism means change of form; metasomatism, change of substance. The term contact metamorphism, however, has been widely misused possibly by a majority of economic geologists and engineers. As originally adopted by European investigators it meant changes effected largely by heat (thermal effects) in the rocks invaded by plutonic intrusives, but did not include those local changes usually at the immediate contact brought about by the addition of substance, i.e., by metasomatism. The term has become clouded. In Europe it has

Jan 1, 1949

By T. A. Dungan

THE thermal processes for the production of metallic magnesium can be divided into two general classifications, the direct reduction of magnesia with carbon and the indirect reduction of compounds of magnesium by reducing agents that are themselves products of carbon reduction. The latter are so chosen as to cause reduction of magnesium compounds wherein only the magnesium is liberated in the vapor phase. Reducing agents used are: calcium carbide, silicon carbide, silicon, aluminum, various silicides or combinations of calcium, aluminum, silicon in iron. All of these are products of highly endothermic reactions and, with the exception of scrap aluminum, can be produced in an open, submerged arc furnace; that is, the arc is covered only by the charge itself. The more investment in energy required to prepare such a reducing agent, the less is the energy required in the subsequent step to reduce the magnesium compound to the metal. It is impossible, however, to avoid the laws of thermodynamics, no matter how much circumambulation is resorted to in the preparation of successively more powerful reducing agents. Since each such step carries forward its own inefficiencies, it appears evident that the ultimate status of such processes is dependent upon the development of by-products. EARLY EXPERIMENTS IN DIRECT REDUCTION The direct reduction of magnesium oxide by carbon has a decided appeal to both the scientist and the industrialist. The successful production of the carbothermic plant at Permanente is a significant fact in the substantiation of this concept. Like most developments, however, the history of carbon reduction of magnesia is not one of triumph after triumph, or immediate heady success to the investigators. It is understood that one of the early investigators conducted an experiment wherein he placed carbon and magnesia in one end of an evacuated tube and managed to heat this end to a temperature high enough that magnesia and carbon deposited at the other end of the tube. The charge, unreduced, appeared to have been completely transported from the hot to the cold end of the tube. This raised doubt for some time as to whether magnesia could be reduced at all with carbon. It was correctly suspected, however, that the magnesia was in fact reduced and the resultant magnesium vapor and carbon monoxide reacted upon one another upon reduction in temperature to reform the starting ingredients. Attempts were then made to dilute the two vapors by passing a considerable stream of hydrogen through an arc furnace charged with magnesia and carbon. Thus by dilution of the products it was expected to obtain metallic magnesium. The results were positive and metallic magnesium was

Jan 1, 1944

By E. J. Fasiska, L. Zwell

PREVIOUS investigations 1,2 of Fe3P described by pearson3 and schubert4 show that Fe3P has a bct unit cell having four Fe3P tetrahedra centered around each lattice point. The space group is 14, No. 82, and all atoms occupy general positions 8(g). The cell dimensions3 are: a = 9.090, c = 4.446 kX, with an axial ratio of c/o = 0.4891. We have measured the lattice parameters of Fe3P, using a Fe as an internal temperature standard, at 23°, 414°, and 678°C and computed the thermal expansion over this temperature range. The Fe,P was prepared by melting under vacuum (after flushing with argon) a commercially pure iron and "ferrophosphor" in a high-frequency induction furnace. Part of the ingot was crushed for X-ray examination and for chemical analysis. X-ray diffraction and light microscopy indicated iron phosphide (Fe3P) present as the major constituent and a small amount (about 5 pct) of a Fe. Chemical analysis showed 0.05 wt pct Si, 0.008 wt pct N, 0.018 wt pet C, and less than 0.02 wt pct each of other metallic elements. X-ray diffraction powder patterns were obtained from a mixture of iron and Fe3P sealed in an evacuated quartz capsule using a Unicam high-temperature

Jan 1, 1968

By Morris Cohen

WITHIN the past two years, a number of publications have called attention to the double peaks, or stages, that appear in the hardness and strength curves of certain aging alloys. The author has shown the existence of double hardness peaks during the aging of a high-purity silver-copper alloy;1 and on the basis of electrical resistance, microscopic, dilation and lattice-parameter measurements, he concluded that the initial hardness peak occurs prior to precipitation while the secondary hardening is due to precipitation. It was suggested that the general mechanism of age-hardening involves two consecutive processes, the first consisting of nucleus or knot2 formation, and the second consisting of actual precipitation and particle growth. It was further held that the two stages are interdependent, but because of nonuniform precipitation they may overlap each other to an extent that increases as the aging temperature is raised. At high aging temperatures, the effect of the first stage cannot be detected because of the rapid occurrence of precipitation. The general theory of age-hardening recently presented by Dr. M. L. V. Gayler3 is in close agreement with the picture outlined above. With reference to work done on duralumin, copper-beryllium and copper-silver alloys, Dr. Gayler also concluded that age-hardening takes place in two consecutive steps: first, diffusion (in which the solute atoms migrate to certain crystallographic planes), and then precipitation. However, W. L. Fink and D. W. Smith4 have shown that the double aging peaks that appear in the strength curves of high-purity aluminum-copper alloys may be explained without recourse to pre-precipitation phenomena. By means of very careful metallographic technique, Fink and Smith demonstrated that during aging the precipitation takes place at an accelerated rate along the grain boundaries and slip planes as a result of the plastic deformation caused by the drastic quench from the solution heat-treatment temperature. ? The general precipitation occurs at a

Jan 1, 1938

By C. S. Matthews, G. L. Stegemeier

In one field in South Texas, approximately 72 per cent of the pressure build-up results show a characteris-i.rtic "hump" (i.e., the pressure builds up and then falls off) which makes interpretation by. standard methods impossible Correlation of size and time of hump with formation permeability. well productivitv index, and method of completion led to the tentativc, conclusion that the humps were caused by segregation of gas and oil in the wellbore after closing-in"'. This conclusion was confirmed by performance of simple laboratory bubble-rise experiments, by theoretical bubble-rise time calculations, and by a detailed calculation of PVT behavior in the well of a particular well Oil which accurate Surface and bottom-hole pressure measure-ments were untile. The hump behavior has since been found to occur in many other fields. The cause, however, is not the mine in all cases. In some of these the hump is trace-ahie to leaks in the tnbing which allow influx from the annulus after closing-in. In other cases the hump is traceable to leaks in the device separating pay horizons in dually completed wells. It is concluded that the recording of both surface and bottom-hole pressures is desirable in wells which show an anomalous build-up behavior. A number of field examples is discussed where use of both sets of measurements enables the cause for anomalous behavior to he found, (and a reasonable interpreation of bottom-hole pressure to be made. INTRODUCTION Theoretically the pressure build-up in an infinite reser-voir should be a linear function of In [(t + at)/nere t is the production time and At a the closed-in time. Some of the variations from this behavior arc well known, such as the curved portion immediately after shut-in which results from after-production and skin effect, and the flattened end portion which results from boundary effects in a limited reservoir. The effect of stratified producing zones and irregular geometrical drainage patterns may also contribute unusual characteristics to build-ups. However, the effect of still another phenomenon—that of movement of fluids within the wellbore—has been neglected in most build-up studies to date. Fluid movements within the wellbore after shut-in occur as a result of after-production, packer failures, leaks in the casing or tubing, or buoyancy of the gas phase when both gas and liquid are present in the well. Each of these movements can influence the pressure build-up, sometimes sufficiently to negate use of the data for computing permeability or stabilized build-up pressure. Examples of each of these phenomena are discussed below. FIELD OBSERVATIONS ON HUMP BUILD-UPS In approximately 75 per cent of the wells in a medium-sized field in South Texas the pressure build-up curves rise to 3 maximum and then decline to what appears to be a stabilized reservoir pressure as shown in Fig. I. Similar behavior has also been observed in wells in other fields in Texas and Louisian:,. Because of the possibility of such behavior being a mechanical failure of the pressure bomb. the bombs were run in tanden into one well which had been known to exhibit this behavior. When both bombs recorded identical curves with the characteristic hump, it was inferred that the unusual build-up is a result of well or forma-

By R. A. Spurling, C. G. Rhodes

SATISFACTORY metallographic sample preparation of very soft metals, such as lead and its alloys is generally difficult. The prime requisite of any technique must be that the result gives an undis-torted microstructure for the microscopist to examine. A small amount of mechanical polishing followed by a chemical or electrolytic polish is usually the most desirable way to obtain an undis-torted surface. Several chemical-4 and electrolytic3-' polishing solutions have been developed for dilute lead alloys. Perchloric acid mixtures (with acetic anhydride, ethyl alcohol, or water) are among the most prominent electropolishing solutions used for lead; however, the presence of bismuth in the alloy precludes the use of any perchloric-containing solution. The other solutions1-7 were found to be unsatisfactory on alloys ranging from 10 to 65 wt pct Bi in lead. With increasing bismuth content, the microstructure shows a lead (terminal solid solution), 0-6 mixture, E (peri-tectically formed hexagonal phase), and E bismuth mixture (eutectic at 56.7 wt pct Bi).9 The metallographic samples were mounted in "Araldite" epoxy (the heat generated during polymerization does not alter the microstructure), ground by hand on well-waxed silicon carbide papers (400 and 600 grit), and polished with 3- and 0.25-CL diamond paste on billiard and microcloths, respectively. The use of the various polishing and etching solutions reported in the literature resulted in the formation of irremovable reaction products on the sample surface when applied to "as-ground" or "as-polished" surfaces. The E phase was the most difficult to clean chemically and in the development of an etchant for this system several solutions which satisfactorily etched the bismuth or a phase were unacceptable because of their reaction with the E. It was found that a mixture of 50 ml lactic acid 30 ml nitric acid 20 ml (30 pct) hydrogen peroxide (Solution #1) was a satisfactory etchant for the a-matrix alloys. The samples were prepared as before and etched after 1 min of polishing with 3-p diamond paste. The etchant was applied by swabbing (light pressure) for 30 sec to 1 min and the sample was then rinsed in running water. The E has a slight stain and the a is fairly bright, Fig. 1.

Jan 1, 1965

By Jean-Jacques Prompsy, J. S. Rinehart

The purpose of the present study was to arrive at a better understanding of the stress fields developed within drill bits under dynamic loading and the influence that these stress fields could have on the failure of the drill bits. Particular emphasis has been given to the influence that bit shape has on the establishment of highly localized, potentially destructive stress inhomogeneities within the bit. This paper covers one phase of a broad study involving three velocity regimes: impacts at very low velocities, 0 to 20 ft/sec, a velocity range in which dynamic effects are just beginning to be found; impacts at velocities ranging from 20 to several hundred ft/sec, arange commonly encountered in practical drilling operations; and impulsive loading through the detonation of explosives, a velocity range in which the dynamic effects are greatly exaggerated and made more identifiable. Specifically, fracturing which develops at the end of a cylindrical bar undergoing a shock produced by impact was experimentally investigated, the impacted area being the face of a truncated cone terminating the cylindrical bar. Fracture characteristics were looked at as a function of impact velocity, area of impacted face and cone angle — parameters of considerable importance in the design of drill bit. EXPERIMENTS The specimens were made of Plexiglas, which enabled the fracture pattern to be easily observed. In Plexiglas, the velocity of a longitudinal wave is about 8,700 ft/sec, and the velocity of the transverse wave about 4,200 ft/sec. The specimens were impacted by a steel cylinder whose lower face was parallel to the terminal face of the experimental bit, as shown in Fig. 1. The impacting mass was shifted up and down on two steel rods, dropping from a maximum height of 11 ft, with the velocity varied between 0 and 6.5 m/sec. The initial mass of the cylinder was 4.1 kg, which could be increased by steps up to 8.8 kg by addition of steel plates. The velocity of the steel cylinder was determined by using an electric circuit; as the cylinder dropped, it contacted two steel wires, the first one starting and the second one stopping an electronic counter. Two similar counters connected in parallel were used to corroborate each other. The velocity was checked at each drop as it had been observed to vary somewhat from drop to drop. The two contact wires were located just above the top of the specimen so as to give a value of the instantaneous velocity of the steel cylinder at impact. The distance between the wires was 40 ± 0.5 mm and the discrepancy between the counters was never more than 0.1 m/sec. Thus the velocity was known to within 3.25 per cent. This precision was sufficient with respect to the precision of the machining of the specimens. A very small lack of parallelism between the face of a specimen and that of the impacting hammer resulted in an oblique impact which required a much lower velocity to break the specimen. The experiments had a twofold purpose — (1) to observe the fracture pattern, and (2) to find relationships between the minimum velocity required to generate a fracture within a specimen and the

By G. Gutierrez, M. C. Fuerstenau, J. D. Miller

The response of pure goethite and two natural iron ores to flotation with potassium octyl hydroxamate is presented. The ores contained 12.5% and 39.7% iron; concentrates containing 69.5% and 61.5% iron, respectively, were obtained with additions of 0.4 lb/ton hydroxamate. Selective flotation of iron oxides from associated gangue minerals has proven difficult in the past with standard collectors, such as sulfonates and fatty acids. As a result, recent work has been directed toward silica flotation with calcium activation after the iron oxide surfaces have been blinded with certain starches.& The results obtained with this technique are encouraging. This method, however, involves depressing a mineral that would normally float under the conditions employed. A preferable method would involve floating the iron oxide because quartz is naturally depressed until activated. Earlier work involved this approach, but in view of the results obtained, collectors that exhibit greater specificity for iron are needed. During an investigation of chrysocolla flotation with potassium octyl hydroxamate, a metal chelate former, it was observed that pyrite floated well with low additions of collector.3 This phenomenon suggests that hydroxamate has a rather strong affinity for iron, and that other iron-bearing minerals should also respond to flotation with octyl hydroxamate. The object of this paper is to determine this response. The experimental work was divided into areas, the first of which involved microflotation experiments with pure goethite with an apparatus described previously.4 Goethite was selected because of the ease

Jan 1, 1968

By J. P. Myers, A. H. Flagg, E. S. Mardock, J. L. P. Campbell, J. M. Terry

The development process for the use of radioactive tracers as a means of locating zones of permeability is discussed. The general techniques for the safe handling of radioactive materials is given as developed by the Lane-Wells Co. and Well Surveys, Inc. The prob1em and. successes with tracers in waterflood systetns, oil and gas injection profiles, fracture sand tracing, squeeze (ement tracing. lost circulution, and cement top localion are discussed and illustrated. INTRODUCTION The exact location of the permeable zones lying within the productive horizon has been a major problem faced by the petroleum engineer for decades, and it has been a problem which has seldom been solved with certainty. Reservoir engineers usually have to incorporate a question mark in their estimates of future reservoir performance because of blanks in the core data. Although the use of radioactivity or electrical logs for the estimation of porosity has been of great assistance in furnishing a record for the reservoir engineer, this application of logging data has not completely solved the problem. In short, the industry needs an in-situ well surveying method which can locate and estimate the permeability of the zones existing within a given pay section. The initial development work with radioactive tracers has been towards filling the need for permeability information. Progress to date permits the location of permeable zones with a qualitative estimate of their relative importance with respect to permeability. The calibration of the method is still incomplete. but present development work on tracer preparations, borehole effect correction factors, and instrument limitations give a promise of quantitative "permeability profiles" in the near future. The development work on the radioactive tracer method discussed here began several years ago in the laboratories of Well Surveys, Inc., in Tulsa. At the outset of this work, three approaches to the problem were visualized as follows: 1. A fluid carrying a soluble, chemically inert, gamma ray emitting isotope is pumped down the borehole and out into the permeable zones of the formation. The greater gamma activity of the permeable zones thus permits them to be differentiated from the impermeable zones which contain no active tracer. It was found difficult to obtain a tracer material which was chemically inert. Absorption to some degree was noted in all experiments. Also, it proved impossible to hold the tracer near the horehole where it could be logged. 2. A fluid carrying a soluble, gamma ray emitting isotope is pumped down the borehole into the permeable formations. In contrast with proposal 1, above. the tracer is chemically active with the fluids and materials in the pore spaces of the permeable zones. The permeable zones are thus indicated by their higher radioactivity level. The main difficulty in this proposal was finding a tracer material which would not be absorbed by shale as well as in the permeable porosity. Very little field work was done with this system. 3. Radioactive particles suspended within the injection fluid are pumped down the well. As the fluid enters the permeable formations, the radioactive particles are filtered out on borehole wall. The permeable zones are differentiated from the impermeable by the gamma ray activity deposited on the formation wall.

Jan 1, 1956

By Fredrick C. Kruger

Anthropological diggings have revealed that the American Indians carried on intertribal trade in flint, obsidian, ochre, and other mineral commodities, indicating that mining was practiced before the arrival of the white man from Europe Carbon datings from the native copper pits on Isle Royal and Keweenaw Peninsula, Michigan, have yielded dates as early as 5555 BC for this mining. As early as Pliocene time, Eolithic-man fashioned artifacts of stones probably found on the surface, but by late Quaternary, Neolithic man was sinking shafts and mining underground for flint. Because placer gold was easily recognized and easily worked, it was used for ornamental purposes by nearly all cultures before other metals were discovered The Chaldeans hammered copper objects approximately 4500 BC and copper was used in India and China about 3000 BC. An ancient trail from the Nile to the Sinai led to the mines of copper and turquoise Paintings and bas-reliefs of Egyptian tombs dating around 3000 BC depict maps, mining, and smelting in this area. It is interesting that despite this widespread and long history of mining, Agricola records that the first mining laws were developed by the Greeks at Laurium about 700 BC. All of the base metals are known to have been produced in small quantities during the Colonial period in America, but perhaps the first commercial production was the iron ore shipped from Virginia to England in 1608, followed by lead in 1621. Among the earliest companies formed in America that still survive (according to the standard reference yearbooks), were: the Jackson Mining Co., predecessor of Cleveland-Cliffs Iron Co. on the Marquette Range, Michigan, in 1844; the Sussex Zinc and Copper Mining & Manufacturing Co., fore-runner of New Jersey Zinc Co. in 1848 (although the Franklin-Sterling body was discovered in 1640); the five companies, Pittsburg and Boston, Quincy Mining, Pewabic, Huron Mining, and Minesota all formed in the decade (1844-1855) that followed the rediscovery of Keweenaw copper, were combined into Calumet and Hecla; and Vermont Copper Mining Co. in 1853 Although southeast Wisconsin lead-zinc was discovered in 1690, Mine La Motte in southeast Missouri in 1720, placer gold in California in 1848, Comstock Lode in 1859, Leadville in 1860, Cripple Creek in 1891, no surviving companies of those early mining periods exist. The first strong producer in the Mississippi Valley was St. Joseph Lead in 1864; Homestake and Pickands-Mather, were formed in 1877, Phelps-Dodge in 1881; Pittsburgh Reduction, the predecessor of Al-

Jan 1, 1976