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By P. G. Shewmon, W. M. Robertson

The derivative of the surface tension with orientation, ??/??, for copper has been measured over the entire unit triangle. This derivative or torque term was determined from the variation of the dihedral angles at the intersection of twin boundaries and free surfaces. High-temperature anneals in graphite with a hydrogen atmosphere gave torque terms of 0.097 at (111), 0.066 at (100), and 0.0257 at (110). A variation from -36oto +23oC in the dew Point of the H2 had no effect on these values, nor did a change from 99.98 to 99.999 pct Pure copper. The removal of graphite from the system decreased ??/?? slightly. Considering the surface near a low-index plane to be smooth except for occasional steps, the free-energy increment per cm of step is calculated, and it is shown that the observed variation of ??/?? is consistent with a random distribution of steps and an interaction energy between steps. Integration of ??/?? gave the relative values of y at (100), (110), and (111) as comPared to ymax: (Y111/Ymax) =0.974, (Y110/Ymax) =0.996, (y100/Ymax) = 0.983. The ratio of the surface tension of coherent twin boundaries to the surface tension of the free surface was found to be (yT/ys) = 0.027 * 0.011. In a crystalline solid the surface tension y (surface free energy per unit area) depends on the orientation of the surface relative to the crystallographic axes of the crystal. Measurements of this variation of y with surface orientation have been reported for metals only within the last few years. Consider the grain boundary groove shown in Fig. 1. Here the three surfaces are all normal to the plane of the paper, and each has a different surface tension, y1, y2, and y3. If the system is at equilibrium, the total surface free energy must remain unchanged for a slight vertical displacement of the intersection (points A, B, and C are kept fixed). As shown by Herring,' the following equation is obtained:

Jan 1, 1962

By Clarence W. Balke

SMALL buttons of fused tantalum have been produced by arc fusion in a vacuum, by drawing an arc between sticks of pressed tantalum and a tantalum-faced water-cooled copper block. However, ingots of appreciable size can be produced only by the heat-treatment of bars pressed from powder. The following outline covering the production of finished bars of tantalum by the methods of powder metallurgy is also used for the production of columbium, taking into account the difference in the melting points of these two metals. PRESSING THE POWDER With possibly a few exceptions, a pressing operation is one of the essential steps in the practice of powder metallurgy. In fact, the author's experience with a number of high-melting-point metals and with numerous types of hard carbide compositions has led him to believe that this operation is often one of the most important in the entire process, and frequently one of the most difficult to carry out in a satisfactory manner. Defects due to improper pressing can readily lead to a defective finished product. It is the author's opinion that rarely is a bar or other article pressed from metal powder in such a way that all parts of the piece are uniformly pressed. The nearest approach to uniformity of pressing is possibly attained when the powder is contained in a flexible receptacle, such as rubber, and is pressed under a liquid by hydrostatic pressure. However, this method is not generally applicable. Hydraulic pressing in steel dies where one or two punches are forced into the die must usually be resorted to. As the pressure in such a die is built up, the powder begins to cling to the walls of the die with a tenacity dependent upon the nature of the powder, and this results in a bridging action, so that the layers of powder adjacent to the moving punch are pressed more heavily than those further removed in the mass. Frequently, as the pressure is carried higher, there may be a mass slippage of the powder upon itself, with the result that slip cracks are formed within the pressed

Jan 1, 1938

J. C. WRIGHT.-The problem of organizing and maintaining a vocational class for those employees who are engaged in the mining industry depends on several most important factors. The first is the sympathetic cooperation of employer and employee; the second is to find the subject matter that must be presented to these men; and the third is to find the instructor who can present that subject matter. This is perhaps the most difficult, for we usually find a man who knows the material that is to be presented but is not a teacher or does not know how to organize his material. The man must know the subject matter from the standpoint of absolute contact with industry in order to be a successful teacher. I have come into contact with two kinds of schools organized in connection with mining occupations. In one type the instruction leans very largely toward elementary subjects, arithmetic, reading and writing and spelling; it is not of such a character as to help or improve the working man in his occupation in the sense that we are attempting when we speak of vocational education. In the other type of school, an engineer is usually employed as a teacher. He immediately begins to give the things with which he is most familiar and the instruction becomes such as only those who possess a high-school or college education, perhaps, are able to receive. In between these two schools is the school we are trying to, promote, a school that will meet the needs of those employed. MARGUERITE W. JORDAN,* Altoona, Pa. -Vocational education has become the business man's problem; for he is the keeper of that white elephant, labor turnover, and anything that will decrease the size of the monster is worthy of serious consideration. This vocational education can do; for it can supply many of those deficiencies in upbringing and. environment that make for the discontent and restlessness of our varied classes of unskilled labor: the Anglo-Saxon mountaineer; the Southern negroes who have crossed Mason & Dixon's line by the thousands, "searching satisfaction for our minds;" and the still greater number who have sought across the sea America, "the promised land.

Jan 4, 1919

By W. G. Woolnough

It is perhaps a little difficult for Americans fully to appreciate the slow progress in the search for oil in Australia. Conditions are so different from those in the United States that methods must also differ considerably. Australia possesses an area almost exactly equal to that of the United States, but has a population of less than 7,000,000, and this population is concentrated almost entirely around the eastern and southern coasts of the continent. There are, therefore, vast "empty spaces" entirely unpopulated or exceedingly sparsely populated. The emptiness is due not to any lack of energy or initiative on the part of Australians but to the arid and waterless character of much of the country's interior. Throughout the greater part of the area that is comparable with the Mississippi drainage area of the United States, there is not a single flowing stream, and over most of it the rainfall is less than 7 in. a year. This hinders exploration and geological survey, and also isolates from potential markets many of the regions that otherwise might be considered worth prospecting. Also, Australia consists of six independent and sovereign states. With the establishment in 1901 of the Commonwealth of Australia, the states retained complete control of lands and mineral rights. Each state has its own petroleum legislation, and the absence of a central controlling authority has tended to confusion and to the introduction of many complications in oil prospecting. There are three major "territories," administered by the Federal Government; namely, the Northern Territory, enclosed between the northern parts of Queensland and Western Australia, within Australia itself, and the Territories of Papua and New Guinea in the island of New Guinea. Land and mineral legislation in these territories is not uniform. Furthermore, during the late twenties there occurred an orgy of company flotation and indiscriminate drilling, wQch resulted in the discovery of some definite indications of oil in three of the states and two of the territories, but which failed to develop any producing oil field in the common acceptation of the term. Much money was squandered,

Jan 1, 1938

By Rudolf Kudlich

The problem of eliminating the hazards of hoisting in mines has been with us since the industry passed its earliest stages, when coal and ore could be won from surface working and tunnels. At first, safety devices were introduced as means of decreasing the amount of labor necessary to produce the mineral, or to increase the amount that could be obtained from a certain opening. For example, crude ladders replaced winding footpaths or steps cut into the walls of the pit or shaft, decreasing the distance it was necessary to carry the product to the surface and eliminating, to some extent, the hazard introduced by the precarious footing afforded by such paths and steps. Latcr, instead of being carried from the pit on the backs of men, the product was hoisted in buckets or baskets on a rope passing over a pulley or around a windlass. Thus the capacity of the pit was considerably increased, and the hazard due to making many trips up and down the shaft was eliminated. From such beginnings accident prevention in mine hoisting advanced with the importance of the industry, until at present hoisting compares favorably with other branches of the mining industry with reference to safe practices. As in the other branches, this progress has been accomplished along two general lines—by legislation, rules, and education, and by the installation of safety devices. Though due credit must be given the former, it is not so satisfactory as the latter. Legislation, to be effective, requires a policing and inspection system to guarantee enforcement, such as we cannot hope to inaugurate. Rules may be satisfactory so long as the employer controls the labor market, and dismissal or some other form of discipline is an effective means of insuring obedience to the rules; but where labor demand is in excess of the supply, or where labor organizations are in control, such measures are not effective. An educational campaign will draw attention to hazards and may awaken a desire to avoid accidents by exercising the proper care. It is necessary, therefore, to place our reliance mainly on mechanical devices to prevent accidents, and to depend as little as possible on laws,

Jan 1, 1923

By G. W. Traer

The distillation of bituminous coals at what is commonly termed low temperature, and the quantities, nature and adaptabilities of the products have been the subject of considerable experimentation, during recent years. Fortunately, the earlier work in this country was done by men whose scientific training qualified them properly to record and interpret the results of their experiments. The work of Prof. Parr, of the University of Illinois, is especially notable in this respect. Prof. Parr's work, added to that of English experimenters, demon-strated-certain things to a degree which is generally regarded as convincing. They have proved that a caking bituminous coal, when subjected to a temperature of not more than 1000" F. (preferably somewhat less) will yield light tar having low specific gravity (about 1.06) and high value; also, that this yield, with a given coal, will depend upon the percentage of hydrocarbons in the coal, the maximum temperature used, and the promptness with which the distillate gases are removed. It is assumed that air is excluded from the retort, and that the coal is subjected to heat for a sufficient time to drive off all of the tarry hydrocarbons. The results attained in the first, or low-temperature stage of the car-bocoal process, recently described by C. T. Malcolmson,1 corroborate these general principles. It is the purpose of the writer to describe other work of a practical nature, directed toward the commercial adaptation of these principles, which was begun nearly two years ago; this investigation was assisted by A. J. Sayers, of the Link-Belt Co., and Carl Scholz. The first step was to draft tentative designs for the handling of the coal and coke so as to produce a coke having a suitable structure for sizing, storage, shipment, and handling, without the necessity of briquetting. Prof. Parr's results had indicated that the rather open-pored volatile coke produced by him had a low ignition point, which would contribute toward easy control of the fire in stoves, house furnaces, fire-boxes, and boilers. It is recognized by those experienced in the marketing of fuels that the hard non-volatile coke from the high-temperature process,

Jan 1, 1920

By R. L. Wiegel

This article proposes a physical model for an idealized binary mineral system and for the process of liberation by size reduction. Based on this model, equations are derived relating the amount of each component liberated as a function of the ratio of the volumetric abundance of the two mineral components and the ratio of the mineral grain size to particle size. A definite relationship is shown to exist between the mineral concentration within a locked particle and the frequency of occurrence of such a particle. These relationships are used to obtain theoretical expressions for the concentration-recovery diagram. Physical mineral beneficiation processes are based on breaking a mineral aggregate to liberate the dissimilar mineral grains and then making use of their physical properties to separate the mixture into its components. The effectiveness of the process is therefore dependent on how well the minerals are liberated and how efficiently they are separated. Although a substantial amount of work is being done to improve our understanding of mineral separation processes, the study of mineral liberation itself has been almost completely neglected. The purpose of this theoretical study is to shed some light on the liberation phenomenon by: 1) proposing a physical model for an ideal binary mineral system, 2) treating mathematically the fracture of this system into liberated and locked particles, and 3) deriving an expression for the liberation characteristics of this system. The results of this study are useful in understanding the effect and importance of various parameters in liberation, and provide a basis for comparison with real mineral systems. 'RANDOM' MODEL It is recognized that liberation can be caused by detachment which results from fractures occurring at the mineral grain boundaries, or by size reduction which restricts the occurrence of dissimilar mineral locking to a portion of the resulting particles. The detachment effect is dependent on the relative strengths of the mineral grains and the bonds between them, and must be treated empirically for each mineral system. The size reduction effect, however, can be treated analytically if certain assumptions are made concerning the shape and geometrical arrangement of the mineral grains.

Jan 1, 1968

By W. R. Ingalls

THE manufacture of zinc oxide directly from the ore is one of the most important contributions that America has made to the metallurgy of zinc. Heretofore, this has been clone chiefly for the production of zinc and zinc-lead pigments, and the method has been known as the Wetherill process. While that term may properly be applied to the process for pigment manufacture, it must be recognized that the principles of the process are of far wider application; and that there is going to be wider application in the immediate future is more than an expectation. I have in mind the use of the process as a method of igneous concentration. Igneous concentration is broader in its scope than the Wetherill process, for it may be done in the blast smelting furnace, or in the reverberatory, or by other means. Igneous concentration is a rather clumsy term, and I prefer to introduce the new generic expression of "zinc burning," which is convenient, readily understood and precise, for in all cases the zinc oxide is reduced to metallic form, is volatilized and is then burned to zinc oxide, the latter happening, however, after the zinc has been separated from the residue of the ore. As previously indicated, zinc burning may be done either in blast or reverberatory smelting, the gangue of the ore being scorified and drawn off as slag, while other metallic minerals are reduced to matte or metal. Such processes have heretofore been practised on fairly large scales. Thus, F. L. Bartlett smelted zinc ores at Canyon City, Colo., in specially designed blast furnaces, wherein the smelting column was only about 18 in. high. Such a limitation was necessary in order to prevent zinky accretions in the shaft of the furnace, which in course of time would have interfered with its operation. In running the Bartlett furnaces it was easy to bar them off, indeed, to poke right down into the smelting zone, and keep things going freely. Some iron blast furnaces in Virginia and the spiegeleisen furnaces of the New Jersey Zinc Co. afford other examples of zinc burning in blast-furnace smelting, although in their cases the happening is incidental rather than a primary purpose.

Jan 9, 1917

By Renato G. Bautista, Robert A. Hard

A comparative study has been made of the ex-tractability of several of the transitim metals from thiocyanate sohtions using methyl isobutyl ketone as the organic solvent. Extractions were made of scandium (III), chromium (III), manganese (II), iron (III), and cobalt (II), of which only the scandium , iron, and cobalt were readily extracted. All extractions were made at pH 2 and at 25.5 °C. A series of extraction experiments was made on scandium, iron, and cobalt to determine the effect of thiocyanate cmcentration added as the ammonium and also as the calcium salt. Also determined was the effect of metal ion concentratim and ionic strength on the distribution ratio. Analyses of the organic extracts indicated the scandium and iron were extracted principally in the uncharged trithiocyanate form, while the extractable form of the cobalt contained the cobaltotetrathiocyanate anion. THE chemical separation of metal complexes in solution by solvent extraction has in recent years been developed for large scale separation as well as bench scale work in the laboratory. It has also found increased application in analytical chemistry. Its extension to extractive metallurgy as a unit operation is best illustrated in the recovery of uranium and vanadium from their leached liquor.5-8 The extractability of some thiocyanate systems have been extensively investigated. The rate earths have been separated from one another using butanol as a olvent. Scandium was effectively extracted in ethyl ether using ammonium thiocyanate as the com-plexing agent.'' Similarly, the separation of hafnium from zirconium has been reported using ether""' or hexone13 as the organic solvent. The extractability of various metal thiocyanates in ethyl ether is given by 0ck.l Sharp and Wilkinson15 prepared nickel-free cobalt slats by thiocyanate extraction. The mechanism of extraction of titanium (IV) thiocyanate with methyl isobutyl ketone was determined by elafosse.''" The characterization of cobalt (TI) thiocyanate complex using methyl isobutyl ketone as the solvent at near neutral aqueous solution and the spectrometric studies of the ex-tractable cobalt complex has been made by Hard." It is noteworthy to mention at this point that the fundamental characteristic of ketone (oxonium) solvent extraction is that the extractable species are uncharged ion pairs solvated by the ketone molecules, but probably still partially hydrated.

Jan 1, 1963

By D. T. MacRoberts

This paper embodies the results of theoretical studies concerning gas reservoirs, especially the effect of drilling programs of various intensities upon pressure depletion and ultimate recoveries. The primary objective has been to determine the net quantity of recoverable gas that could be obtained as a result of each additional well, in comparison with the gas . that might be secured from a single well ideally placed with respect to both acreage and geological structure. No method is yet known whereby the relative merits of intensive and sparse drilling can be compared experimentally; a reservoir must either be drilled closely or developed with wide spacing, but both programs cannot be conducted simultaneously. Hence, the analytical method seems to be the only approach to the problem. While the present state of our theoretical knowledge does not offer a precise solution to the problem of gas flow in sand bodies, it takes such appropriate cognizance of the limitations of the methods used as to restrict any answer obtained to the realm of engineering accuracy. In solving the problem for the average gas field, it was found that practically the same answers resulted as to pressure distribution, regardless of the size of the drainage radius, even though the latter was assumed to vary from a few feet as a minimum to that of the entire reservoir as a maximum. Such limits represent extreme possibilities; therefore, the practical conditions that are associated with normal development programs, in which wells are placed in the center of tracts varying in size from 40 to 640 acres, will of necessity result in less extreme variations than those indicated in the tables accompanying this paper. Stated more concisely, the amount of gas unrecovered at abandonment (of the particular field used for illustrative purposes) will lie somewhere between 4.6 and 6 per cent of the total original content, no matter how intensively the field is drilled. Gas reservoirs may be divided into two general types, those in which the energy is intrinsic, and those of which the energy is extrinsic. † The first type contains energy in the form of a compressed gas, which expands

Jan 1, 1938

By Rudolf Kudlich

The problem of eliminating the hazards of hoisting in mines has been with us since the industry passed its earliest stages, when coal and ore could be won from surface working and tunnels. At first, safety devices were introduced as means of decreasing the amount of labor necessary to produce the mineral, or to increase the amount that could be obtained from a certain opening. For example, crude ladders replaced winding footpaths or steps cut into the walls of the pit or shaft, decreasing the distance it was necessary to carry the product to the surface and eliminating, to some extent, the hazard introduced by the precarious footing afforded by such paths and steps. Latcr, instead of being carried from the pit on the backs of men, the product was hoisted in buckets or baskets on a rope passing over a pulley or around a windlass. Thus the capacity of the pit was considerably increased, and the hazard due to making many trips up and down the shaft was eliminated. From such beginnings accident prevention in mine hoisting advanced with the importance of the industry, until at present hoisting compares favorably with other branches of the mining industry with reference to safe practices. As in the other branches, this progress has been accomplished along two general lines—by legislation, rules, and education, and by the installation of safety devices. Though due credit must be given the former, it is not so satisfactory as the latter. Legislation, to be effective, requires a policing and inspection system to guarantee enforcement, such as we cannot hope to inaugurate. Rules may be satisfactory so long as the employer controls the labor market, and dismissal or some other form of discipline is an effective means of insuring obedience to the rules; but where labor demand is in excess of the supply, or where labor organizations are in control, such measures are not effective. An educational campaign will draw attention to hazards and may awaken a desire to avoid accidents by exercising the proper care. It is necessary, therefore, to place our reliance mainly on mechanical devices to prevent accidents, and to depend as little as possible on laws,

Jan 1, 1923

By F. D. Rosi

IN the production of single crystals by the Bridg-man method of solidification from the melt in vacuum at a crucible lowering rate of 0.25 in. per hr, a cellular structure was frequently observed in copper and copper-base alloys at the terminal surface of the as-cast crystals (i.e., the surface representing the last portion of the crystal to solidify). The geometrical form of this structure varied from crystal to crystal, but, in general, could be classified as either hexagonal or quadrilateral. Fig. 1 shows examples of this cellular structure, which is similar to that reported by Buergerl and, more recently, by Pond and Kessler&apos; and Rutter and Chalmers. In the micrographs of Figs. lb and c, the cubic structure in the alloy crystals is obscured somewhat by excessive surface evaporation in the final stages of solidification. X-ray orientation studies indicate that the traces outlining the various geometrical forms correspond to octahedral planes, which are the planes of greatest reticular density in the face-centered cubic lattice. It would appear from this that the view first propounded by Bravais,4 that the surface energies and normal growth velocities of the different crystal planes are inversely proportional to their reticular densities, applies to this cellular structure, since those surviving are the planes of greatest atomic density. Thus, the observed variation in the geometrical form of this structure in crystals of different orientation is readily understandable from the distribution of the (111) planes in the standard {111}, (1101, and (1001 stereographic projections. Depending upon whether the crystal axis (i.e., the direction of crystallization) coincides with a <111>, <111>, or <100> direction, the cellular structure viewed from a surface perpendicular to the crystal axis will consist of a network of regular hexagons, skewed hexagons (with interfacial angles of 110" and 125"), or cubes, respectively. It follows, moreover, that off-orientations from these principal directions will yield modifications of these three basic geometric configurations. In this connection, it is interesting to note that the bounding planes of the hexagonal structure observed in tin by Rutter and Chalmers3 showed no preferred orientation.

Jan 1, 1954

John Chipman (Massachusetts Institute of Technology, Cambridge, Mass.)—After looking over the authors&apos; shoulders for several years and after many discussions on the interesting diagrams of the types shown, it is a pleasure to see a formal paper published on this subject. There can be no doubt of the practical usefulness of the concepts shown. Inclusion formation in steel is such a highly complex matter that any system for understanding the subject is bound to be welcomed by those who must work with steels and who see in their day-to-day experience the good and evil effects of inclusions. A feature of the work with which the discusser has been concerned, and which he would now like to attempt to explain, is the relation between the schematic diagrams which the authors use and the phase diagrams for related systems. Obviously, the authors&apos; diagrams are in no sense complete phase diagrams. However, there is a relation between this type of diagram and the true phase diagram, and the understand- ing of this relation ought to help in understanding the general picture which the authors are presenting. Consider the authors&apos; Fig. 4, which shows the liqui-dus relations in the Fe-Mn-S-0 system. To show the complete relations between temperature and composition in these four ternary systems would require four triangular prisms, the vertical axes of which would represent temperature. The four triangles of Fig. 4 represent basal projections of certain lines from the four prismatic phase diagrams. Readers of the paper are all more or less acquainted with this type of projection and its usefulness and limitations are generally understood. In order to concentrate on the interesting parts and to minimize the less interesting features, the composition scale may be shifted to de-emphasize regions containing gaseous sulphur and oxygen. Such a diagram is shown in Fig. 16, which is a distorted version of the authors&apos; Fig. 4. Here the oxide of iron is wiistite, denoted by W, and it is to be noted that between W and MnO lies the entire MnO-FeO "binary" system. Similarly, between MnS and FeS lies another binary whose

Jan 1, 1956

By Clarence W. Balke

Small buttons of fused tantalum have been produced by are fusion in a vacuum, by drawing an arc between sticks of pressed tantalum and a tantalum-faced water-cooled copper block. However, ingots of appreciable size can be produced only by the heat-treatment of bars pressed from powder. The following outline covering the production of finished bars of tantalum by the methods of powder metallurgy is also used for the production of columbium, taking into account the difference in the melting points of these two metals. Pressing the Powder With possibly a few exceptions, a pressing operation is one of the essential steps in the practice of powder metallurgy. In fact, the author&apos;s experience with a number of high-melting-point metals and with numerous types of hard carbide compositions has led him to believe that this operation is often one of the most important in the entire process, and frequently one of the most difficult to carry out in a satisfactory manner. Defects due to improper pressing can readily lead to a defective finished product. It is the author&apos;s opinion that rarely is a bar or other article pressed from metal powder in such a way that all parts of the piece are uniformly pressed. The nearest approach to uniformity of pressing is possibly attained when the powder is contained in a flexible receptacle, such as rubber, and is pressed under a liquid by hydrostatic pressure. However, this method is not generally applicable. Hydraulic pressing in steel dies where one or two punches are forced into the die must usually be resorted to. As the pressure in such a die is built up, the powder begins to cling to the walls of the die with a tenacity dependent upon the nature of the powder, and this results in a bridging action, so that the layers of powder adjacent to the moving punch are pressed more heavily than those further removed in the mass. Frequently, as the pressure is carried higher, there may be a mass slippage of the powder upon itself, with the result that slip cracks are formed within the pressed

Jan 1, 1938

By Ralph J. Schilthis

Several investigators1-8 have reported evidence of the existence of native or connate water in oil-and-gas-bearing strata. Both water and salt have been detected in cores of oil sands that yielded oil and gas exclusively when produced. Electrical logs often reveal unexpectedly low resistivity through oil and gas sands, indicating the presence of some material that is a considerably better conductor of current than oil and gas. Furthermore, calculationsg of the oil and gas content of reservoirs based upon production and reservoir-pressure decline data indicate appreciably lower values than are arrived at under the assumption that the pore space is occupied completely by oil and gas. Origin and Occurrence of Connate Water in Oil-and-gas-bearing Formations The view has been expressed, 10-15 and is generally agreed upon, that the expulsion of oil and gas material from source beds and the subsequent migration and accumulation occurred in the presence of salt water. As the strata that usually form reservoirs for oil and gas were laid down by, or in the presence of, ancient seas, the pore space within the strata must have been saturated with salt water before the entrance of the oil and/or gas. Thus, the accumulation of oil and/or gas in the upper regions of structures suitable for reservoirs must have required displacement of the connate water therefrom. In the absence of any forces other than gravitational, it would be expected that the displacement of the connate water out of the zones finally occupied by gas and oil would be complete, and that the vertical distribution of gas, oil, and water in a reservoir would be strictly in the order of their densities. Apparently, however, surface and interfacial forces that will not permit complete segregation of the fluids are active within the capillary spaces comprising a reservoir. The effects of these forces on both accumulation and production of oil and gas have been the subject of study by a number of investigators.16-37 In general, the view is held that the character of most materials that make up the reservoir rock leads to preferential wetting of the rock by

Jan 1, 1938

By Ezequiel Ordonez

The great activity with which the oil resources of the northern Cantons of the State of Veracruz have been developed has largely resulted from the great success obtained by the important explorations carried out since 1902 in the Ebano district in the North, and several years later near Tuxpam, in the South. It must not be thought that these successes were quickly obtained, since the preliminary studies by good experts, the acquisition of what were thought to be the most promising coast lands, the extensive clearing thereof, and finally the number of unsuccessful drillings at great depth, signified an original outlay of some tens of millions of dollars before finding commercial oil. The discovery of oil in industrial quantities at Cerro de la Pez, Ebano district, and the famous Dos Bocas gusher some years later, which was burned, once and for all made famous the Veracruz coast, where today is concentrated the Mexican output of mineral oil. In 1917, this production was nearly 61,000,000 bbl. It is well known that this output represents only a fraction of what the wells in actual production can furnish, because with adequate means of transportation and storage, the present extraction could be somewhat over 300,000,000 bbl. a year. These enormous potential oil resources of the Veracruz coast proceed from a relatively small number of wells, scattered over a few oil fields, separated from each other by large unexplored areas, wherein may be found other favorable fields which, in time, will undoubtedly become just as great centers of oil production. Experts who know our Gulf Coast believe that lands with commercial oil resources lie not only between the Pgnuco and Tuxpan Rivers, but that indications are that the oil zone of Mexico, with more or less interruption, takes in the coast zone from Northern Tamaulipas to the foot of the Sierra Madre of Chiapas, and the banks of the Usumacinta River. This generalization is not merely the outcome of optimism, but is the result of the persistency with which one finds, throughout this Gulf Coast, the most usual characteristics upon which we depend for recognizing oil-bearing lands.

Jan 1, 1920

By Earl Oliver

The term oil property, in this discussion, includes any type of easement or grant under which petroleum might be produced; it ranges from the mere right to drill on undeveloped wildcat acreage up to a fully developed oil property. The values of an oil property, as thus defined, vary widely according to the use for which it is intended, whether it is from the viewpoint of the speculator, the fraudulent stock promoter, the refiner and pipe-line owner, or the oil producer. The market value of a property is usually a combination of some two or more of these influences, and occasionally a combination of all of them, but we prefer to treat each viewpoint as distinct from the others, allowing the reader to make his own combination in such proportions as his inclination and property seem to require. This paper will treat the subject from the viewpoint of the oil producer. However, the other influences have such bearing on the cost of property to the producer and on the price he might obtain by its sale as to warrant brief discussion of them. Speculation, particularly lease speculation, is a parasitic growth on the oil industry, healthy enough, but of no economic value. The class of property usually dealt in for this purpose is the undeveloped lease. Its speculative value may have some relation to its probable productive value, but most frequently this value is the product of temporary excitement due to local development. The lease speculator, seeking out the trend of development or securing early information regarding a proposed test or a new discovery, immediately secures leases whose market value will be increased when the existence of such development becomes more widely known. His profits are purely unearned increment. Not proposing to spend money in exploration, he can afford to compete in purchase with the operator, who, in addition to bonus paid, must spend large sums in testing out his own acreage and that of the nearby speculator as well. It has a tendency to compel unduly high bonuses. The so-called "checker-board1&apos; system of leasing wildcat acreage by the larger companies is on the same principle of attempting to secure the

Jan 1, 1921

By R. E. Rick-Secker, W. M. Baldwin, R. McC. Baker

The development of residual stress in strip during rolling has not been systematically studied. A few scattered papers1 -3 mention the existence of residual stresses in rolled strip or touch upon some of their consequences,4 but there is no report of experimental studies in the literature describing the effect of roll diameter, strip thickness, reduction per pass, metal or metal temper on the magnitude of residual stresses developed in strip. A knowledge of the effect of these factors is of utmost importance since the present trend in some mills to roll thicker castings brings the rolling operation directly into that set of conditions which, as will be brought out in the present paper, can develop residual stresses of a high order of magnitude. Fundamentally, residual stresses are developed when a metal is inhomogeneously unloaded from a plastic stress state. A quantitative treatment of the problem requires a reasonably complete understanding of both the plastic stress state existing in the metal during deformation and the elastic stress state that would exist in the metal if the metal deformed as a perfectly elastic body. Our knowledge of either state during rolling is so meager that we can make no more than certain limited predictions. The external stress state* operating between the roll and the metal consists of Fig i—External stress state operating on metal being rolled (after siebel and LUEG5) compressive stresses acting almost perpendicularly to the strip surface but varying in intensity both across the width of the strip and along the length of contact between the roll and the strip. An example of such a stress distribution is shown in Fig I. The nature of the internal stress state, produced by this distribution, is not known. Various investigators,5-7 however, have felt that a qualitative similarity must exist between the internal stress state so produced and that produced in a wide strip that is compressed between two flat-nosed punches. In the latter case the external stress state is represented by a uniformly distributed compressive stress acting per-pendicularly over the face of the tool. The

Jan 1, 1949

By R. W. Waterfill

MANY existing ore deposits of valuable metals have been worked out in their upper surface levels and the continued productivity of these mines is dependent on their extension to greater depths in the earth. The maximum depths at present reached are about 6000 to 8000 ft. below the surface, with no evidence of an impoverished ore vein. These mines are widely distributed; some of the best known are in South Africa, Brazil, India and in the western sections of the United States. Among the factors which increase the difficulty of working these mines at increasing depths are hoisting, rock pressure and temperature. The manner and effectiveness with which these problems arc met will, no doubt, determine in a large measure the ultimate depths to which any mine can be profitably worked. The most critical of these three factors at present is the increase in temperature with depth. The high temperature and humidity in many of these mines at present are severely detrimental to the health of the workers and greatly hamper their efficiency. Some have almost reached a condition in which the human system cannot survive. The problems involved in the cooling and ventilation of mines have all been ably analyzed and presented in previous articles. For this reason, only a résumé of conditions affecting the cooling and conditioning of deep and hot mines will be given in this paper before attention is directed to possible methods of improving atmospheric conditions in the working levels. Physiological Effects of Temperature, Humidity and Air Motion Many data on the physiological effects of different atmospheric conditions on the human system have been compiled and published through the combined efforts of the American Society of Heating and Ventilating Engineers, the U. S. Bureau of Mines and U. S. Public Health Service. These data were not primarily developed around the conditions existing in deep mines, but the upper temperature limits of the investigations extend into, and are applicable to, mine atmospheric conditions. While the exact values of the standard comfort conditions, established for persons of such habits as those employed in detecting the different degrees of comfort, might not produce identical effects upon persons inured to

Jan 1, 1929

By E. P. Pfleider, O. Rellensmann

For many years mine surveyors and exploration engineers have sought an accurate means of transferring meridian underground by using the gyro-compass. These efforts have generally failed, either because they were inaccurate or because the size and cost of the unit were prohibitive. During the past ten years, however, great strides have been made. Autonetics in California has developed a comparatively light-weight (100-lb) gyro-theodolite, and the Institute for Mine Surveying at Clausthal Mining Academy in Germany has developed an instrument that is accurate to within 20" to 30" of arc. Concurrently, Minneapolis-Honeywell has produced an astounding gyro, the size of a salt shaker, that weighs less than 0.5 lb and compares favorably in performance with the 50-lb gyros of conventional design. This unit, designed for missile guidance, should be adaptable for surveying small boreholes. Given the proper interest and approach from the engineering fraternity, excellent gyrocompasses could probably be available for accurate underground survey work at nominal cost within the next three years. Principles of the Gyro-Compass: The gyrocompass, used for 50 years as a navigational instrument in ships and aircraft, senses the turning axis of the earth and points out true polar north. It does this by employing the earth&apos;s rotation, the force of gravity, and the precession characteristics of a gyro. For further details the reader is referred to several excellent publications&apos;"3 covering the principles and application of the gyroscope. The heart of the gyro-compass is the gyroscope, or rapidly spinning wheel, which rigidly maintains its angular orientation in inertial space. Free gyros employ universal joints to allow the wheel axle to maintain its rigid spatial orientation independent of base motion disturbances. Free gyros are independent of the earth&apos;s turning and are not north-seeking. Only as they might be initially oriented parallel to the earth&apos;s turning axis could any north indication be obtained. In practice, the free gyro tends to drift off its set position and lose its accuracy. The Sperry-Sun Well Surveying Co. instrument (5M in O. D.) is of this free gyro type. It is counterbalanced, however, against the rotational effects of the earth, so that orientation of the spinning axis will be maintained throughout the survey.

Jan 1, 1960