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By A. M. Talbot

THERE is still considerable controversy as to the exact nature of the mechanism of the age-hardening process, in spite of the many experi-ments already performed. For this reason, a considerable number of typical systems should be examined in detail and their results correlated. Furthermore, the methods of studying the changes that take place during the progress of this phenomenon should be carefully scrutinized and the different methods applied to the same samples, preferably at the same time. The experiments described in this paper are presented to supply information on one age-hardening system and to show how the various methods of investigation compare in their indication of what has hap-pened. In brief, the progress of aging in magnesium alloys containing about 10 per cent by weight of aluminum at different temperatures was followed by measurements of hardness, electrical resistivity, dilation and lattice parameter, and by microscopic observation.

Jan 1, 1936

By Jack White

This paper gives details of the results - of careful testing carried out on two types of ball mills, conical trunnion overflow and cylindrical grate discharge, on identical ore. The object of the test work was to determine which ball mill was the most economical to install for future extensions to the Mufulira concentrator.

Jan 1, 1950

By Joseph G. Franzone, Alan K. Kuhn, Jerry J. Oliver

INTRODUCTION Tailings produced by many uranium milling operations consist of fine sands with some silt and slimes. When fine sandy materials are placed by hydraulic methods behind an impermeable dam, they are deposited in a loose state and some portion remains saturated. These saturated, loose fine sands are highly susceptible to liquefaction, the phenomenon in which a monotonic or cyclic disturbance causes excess pore water pressure and, concurrently, a total loss of strength in the sand. Once liquefied, the fine sand flows, causing collapse of supported structures. The potential for such a liquefaction failure was identified and successfully treated at Sohio Western Mining Company's L-Bar Uranium Operations near Seboyeta, New Mexico. The Sohio tailings dam is an earthfill starter dam with tailings raises constructed upstream of the starter dam crest. Beginning with the start of mill operations in 1976, tailings were deposited hydraulically in the impoundment behind the starter dam. As the tailings level approached the crest of the starter dam, beached tailings were excavated and placed in lifts by a dozer to form two raises above the crest of the starter dam. As the impoundment has gradually filled with tailings, the decant water pond level has risen. Correspondingly, the water level in the tailings dam, upstream of the chimney drain, has also risen. By August 1980, the phreatic surface was above the crest of the starter dam and stability analyses indicated that the tailings dam did not have the safety factor of 1.0, under static loading with liquefaction, implicit in the 1980 New Mexico State Engineer's requirements. The problem related directly to the high phreatic surface in the loose sandy tailings behind a dam structure that was not capable of resisting failure which might develop in liquefied tailings. Two methods of stability enhancement were considered for the Sohio dam. One method was reinforcement of the dam using a clay buttress placed against the downstream slope. The other method was installation of horizontal drains through the starter dam to drain decant water and lower the phreatic surface. Either method would increase the stability of the dam. However, the comparative analysis of the methods indicated that horizontal drainage offered significant advantages in cost and could provide a more direct remedy of the source of the problem, the saturated section of tailings. In addition, a drainage system would be more amenable to modification and more quickly installed than a buttress. On the other hand, a clay buttress could be more directly controlled, would involve routine earthwork, and has successful precedent. Therefore, the buttress approach would involve less risk. After weighing the advantages of both methods and the costs versus risks, the horizontal drainage approach was selected. Consequently, a horizontal pipe drain system was recommended and designed (D’Appolonia, 1981a). This paper describes the design and installation of the drainage system and its initial performance. PIPE DRAIN SYSTEM DESIGN Design Criteria and Parameters To increase the stability of the dam to acceptable levels, the drainage system had to lower the phreatic surface behind the dam to the level calculated to give a minimum safety factor of 1.0 under conditions of liquefaction. In addition, the system needed to be essentially self-operating, easy to maintain, and economical. To accomplish these objectives, the following design criteria were established: 1. The pipe drains must lower the phreatic surface at least 4.3 m (14 ft.) at the midpoint along the dam (the deepest section) and by proportionately smaller amounts toward the abutments to satisfy safety factor requirements.

Jan 1, 1982

By Samuel H. Dolbear

THE value of a mine is basically dependent on its capacity to yield profits. Since the ore must be mined, treated, and sold, some of it in various future years, there is a risk involved as to future costs, selling price, and working conditions. It cannot be expected that the economic condition existing at the time of valuation will continue unchanged for long periods in the future.

Jan 9, 1953

By J. E. Johnson

The brief contribution of Mr. West* furnishes a text for the present paper, which will, however, take a wider range, warranted by the writer's somewhat unusual opportunities for the study of the practice of the foundry as well as the blast-furnace, and especially of the production of satisfactory castings from iron of a composition altogether unsuitable, in the opinion of the average foundryman, for that purpose. Mr. West has observed that plates cast from direct-metal of a certain composition could be planed, whereas this would have been impracticable with cupola-metal of like composition; that furnace-metal has more " life " (i. e., fluidity, or a higher temperature) than cupola-metal; that it throws out much " kish," etc. And he suggests that blast-furnace managers may throw further light on the greater softness of direct-metal castings. Perhaps such light may be furnished to some extent by the present paper. The difference between cupola-metal and furnace- or direct-metal is, first of all, in the lower average sulphur-content of the latter. It has been proved by experiment that iron increases in its content of sulphur to a considerable extent with each remelting. More than thirty years ago Fairbairn showed that a certain iron after remelting 18 times had only five-

Jan 1, 1905

By Wilson Blake

As a part of a USBM-ASARCO cooperative rock-burst research program, a burstprone stope pillar at the Galena mine was successfully destressed. Destressing was accomplished by blasting a single line of long holes in the footwall of the vein. As a result of destressing, the pillar was fractured and softened; hence it yielded, releasing a large amount of stored elastic strain energy nonviolently. In addition, the high stress in the pillar was shifted out around the stope walls and in the sandfill. Both broad-band microseismic monitoring and seismic velocity surveys were used to evaluate the destressing test. The mechanics of destressing were determined by finite element computer model studies of destressing. Results of the field destressing test agreed remarkably well with the predicted results from the computer model.

Jan 1, 1973

By R. H. Maes, R. E. de Strycker, J. J. Jacobs

A simple method, based upow density measurements, has been perfected in order to determine the critical temperature of liquid miscibility gaps. Applied to the Pb-Cu system, it yielded a value of 980"C for the critical tempevature of the miscibility gap in this system. In the Pb-Cu-As system, the immiscibility between lead and coppev evolves towards a miscibility gap be-tween lead and copper arsenides; the liquation temperatures were determined joy different avsenic contents and values up to 1065°C were found. Combining these results with those given by the clzemical analysis of liquid samples taken at dqj.event temperatures, it has been possible to make a cowzplete determination of the liquid miscibility gap in this ternary system. In the Pb-Cu-Fe-As system, a ternary miscibility gap has been discovered; for some compositions, the molten and slowly cooled alloys separated into three layers: an Fe-As alloy, a Cu-As alloy, and a lead-rich layer. ThE Pb-Cu-Fe-As system is of interest for the study of the behavior of speiss or arsenical alloys in the lead blast furnace. The speisses produced in lead metallurgy generally have complex compositions, but they may be considered, in a simplified way, as a mixture of copper, iron, nickel, and cobalt arsenides; there is often an excess of metallic constituants, and lead is also present. Speisses liquate from lead at various temperatures according to their composition; according to industrial experience, iron speisses are already distinctly separated from lead bullion at temperatures of the order of 1100°C, whereas copper speisses only begin to liquate from lead at much lower temperatures, near their solidification points, which were never accurately determined until now. Besides these considerations of practical interest, the present study is of importance for the knowledge of liquid miscibility gaps. Particularly the data of the literature about critical temperatures of liquation are incomplete and present sometimes considerable disparities; a method has been perfected in the present work to determine these temperatures with accuracy. MISCIBILITY GAP OF THE LEAD-COPPER SYSTEM Review of Literature. The generally admitted outline of the Pb-Cu equilibrium diagram is shown by Fig. 1. This figure, with its numerical indications, is taken from the review of Hansen and ~nderko;' compositions are given in weight percent, as will be the case in the remainder of this paper. Between 36 and 87 pct Pb, Pb-Cu alloys separate into two layers, in the liquid state. The critical temperature of liquation has been much disputed in earlier studies, where values up to 1500°C were claimed; but a reliable study of ~ohnen,' based upon differential thermal analysis, gave a value of 990°C; this rather low value was verified by a recent study of Schiirmann and Kaune? based upon thermodynamical properties of the Pb-Cu alloys, which predicted a value of 1002°C. Liquid miscibility gaps were also studied by means of chemical analyses. Satisfactory results were generally obtained with the method consisting in taking samples of the two liquid layers in equilibrium and submitting them to chemical analysis; however, this method becomes delicate near the critical temperature. With this technique, Friedrich and waehlerts ob-

Jan 1, 1968

As desirable as it may be to a geologist to have maximum detail in any geological report, the task of doing so for an area as vast as British Columbia within six average size magazine pages is clearly impossible. As a result, it has been necessary to draw a fairly broad picture of the geology on the following pages, but it is one which should be adequate to give the reader a concept of what rock is where in the Province. In preparing this horseback ride over the strata of the Province, much reliance has been placed on various reports appearing in trade and Canadian Government journals. Of these, one in particular stands out. Entitled "The Cordilleran Region", this report has been authored in three parts by H. S. Bostock, R. Mulligan and R. J. W. Douglas, respectively, and is included as a major chapter of the book Geology and Economic Minerals of Canada. Published in 1957 by the Department of Mines and Technical Surveys, the book has provided the extensive quotes, taken from each of the three authors, which appear on the following pages.

Jan 12, 1963

HARRY B. BARREN Harry B. Barren, born in Cleveland, Ohio, May 31, 1888, died in Indiana Harbor, Ind., on Mar. 18, 1918. After graduating from the Case School of. Applied Science of Cleveland, class of 1910, he spent a year at the Youngstown, Ohio, plant of the Carnegie Steel Co. and the following two years with the National Tube Co. in Lorraine, Ohio. In 1913, he went to Indiana Harbor as assistant superintendent of the blast furnaces of the Inland Steel Co. Four months later, he was made superintendent. On Feb. 11, 1914, he was married to Miss Anna E. Jones in Cleveland and is survived by his widow and two sons, and by his parents Mr. and Mrs. H. A. Barren, of Cleveland, and a brother Kenneth, a lieutenant in the 309th Engineers, stationed at Camp Taylor, Louisville, Ky. CHAS. H. JOHNSON Charles Harmany Johnson died Dec. 10, 1918, at his home in New Castle, Pa., after an illness of more than four weeks brought about by a complete nervous collapse. He was born near Clinton, Lawrence Co. Pa., July 9, 1870, a son of George W. and Elizabeth A. Johnson. His parents moved to New Castle when he was two years old, where he attended the public schools of New Castle. He then attended Allegheny College, and later Massachusetts Institute of Technology where he graduated as a mining engineer. For a year and a half after completing his work at Boston he was connected with the Mesaba Ore Range in Minnesota, and then returned to New Castle and became associated with his father in the operation of the old sheet mill, which was converted into a tin mill and later sold to the American Sheet and Tin Plate Co. Since that time he has been actively engaged with his father in the limestone business and other industries. At the time of his death Mr. Johnson was general manager of the Pittsburg Limestone Co., the G. W. Johnson Limestone Co., the Lawrence Limestone Co., the Keystone Limestone Co., and the Mahoning Limestone Co., all of which have quarries in Lawrence, Butler, Blair and Armstrong counties and also in Maryland and West Virginia. He was president of the Johnson Bronze Co., the National Stone Co., and the

Jan 3, 1919

By R. A. Swalin, L. A. Neimark

The research work presented in this paper had initially a two-fold goal. First, further data concerning the low-temperature recovery of cold work was desired. Recovery phenomena have been extensively studied in face-centered-cubic metals but at the time of initiation of this research, no investigation concerning the low-temperature recovery in body-centered-cubic metals had been made. During the course of the investigation a paper by Martin on the recovery of point defects in molybdenum appeared.&apos; Comparison of our results on tungsten with Martin&apos;s results on molybdenum will be made. Secondly, knowledge concerning the influence of a particular type of impurity addition on the recovery kinetics was desired. It has been known for a long time that extremely small amounts of certain impurity additions exert a profound influence on the recrystallization behavior and the resulting microstructure of tungsten. Small amounts of potassium silicate and aluminum chloride added prior to the reduction of tungsten oxide to the metal have been found by Smithells to raise the recrystallization temperature markedly,2 and yield an ultimate microstructure in which grains several millimeters long are produced in fine wires of say 10 mil diam. If the impurities are added singly, ordinary secondary recrystallization results with none of the spectacular properties of the wire to which special additions were made. Swalin and Geisler3 and Rieck4 have studied the recrystallization behavior of such doped wire in some detail. The former workers found that small amounts of these impurities raised the recrystallization temperature over 400°C and electron microscopic examination revealed no obvious inclusions in the microstructures. In fact. chemical analysis showed that there was <0.001 pct K, <0.002 pct Al, trace of Si, and <0.0003 pct 0 in the wire studied. The possibility that the role of the special impurities is to keep the structure open by void formation and that submicroscopic porosity acts as the inhibiting agent has been discussed.2&apos;3 Meijering and Rieck5 have suggested that the impurities are strung out as second-phase particles in a direction parallel to the drawing direction. It was thought that a kinetic study of recovery could perhaps elucidate the role of the impurities to some extent. When a metal is deformed by cold work three basic types of defects are thought to be introduced into the crystal lattice, namely, interstitials, vacancies, and dislocations. Van Bueren6 has proposed that recovery of cold-worked metal is a four-stage process, each step being the result of the annealing of a primary defect or a combination of defects and having a unique activation energy. The steps in order of increasing activation energy are attributed to a) the diffusion of interstitials recombining with vacancies, b) diffusion of vacancy pairs, c) the diffusion of single vacancies, and d) climb of dislocations. In metals with relatively low- or medium-range melting points the temperatures for recovery are low enough so that the first three steps may occur during room-temperature deformation. For tungsten, because of the high melting point and subsequently high recovery temperature, it was calculated, using Nowick&apos;s approach7 that this recovery would occur in the temperature range 200" to 600°C. It is also known that recovery of X-ray line broadening, presumably due to dislocation climb, occurs at about 600°C.8 EXPERIMENTAL METHOD Two types of cold-rolled 10-mil-diam tungsten wire were used in the investigation; a) pure tungsten, (called undoped) and b) G. E. No. 218 wire (called

Jan 1, 1961

By Frederick W. Bacorn

The paper of Reno H. Sales on Ore Deposits at Butte, Mont.,&apos; is a careful and painstaking work, an important contribution to the literature of the subject. As is almost inevitable in a work of such magnitude, a few misstatements occur; and some of these I shall endeavor to point out. Mr. Sales has also fallen into error, as I think, in the application of his theory of ore deposition; and while the modification which I venture to suggest is a minor one geologically, it is of great economic importance. I refer to Mr. Sales&apos;s idea of an outward migration of mineralizing solutions from a supposed central copper zone. In order that I may make myself plain, I must first epitomize the theory as a whole, which I understand to be this: All of the Butte ore deposits (save those along the Continental fault, not herein considered) are derived from solutions of magmatic origin, which, at the beginning of their ascent from a great depth, were acid in reaction, hot, and were carriers of copper, zinc, manganese and other metals. As they departed from their point of origin they lost heat, and, because of reactions with the wall rock, became more and more alkaline. The metal deposited from these solutions in their hot condition was principally copper; and, as they cooled, they deposited less and less copper and more and more manganese and zinc, until the copper practically disappeared. With this theory in general I have no fault to find, nor have I, it must be stated, the qualifications necessary to enable me to pass upon it critically; but it seems to me to be reasonable and probable, and is one which I am quite willing to accept. But Mr. Sales, for what seem to me to be insufficient reasons, has assumed that there is one deep central source of copper, relatively rich and small, from which all the solutions emanated. From this central source the solutions rose, through one channel or through a group of channels, to the surface, at and within a small area called the central copper zone,

Jan 1, 1915

By George R. Cowan

A number of studies hare been reported of the effects produced in metals subjected to deformation by shock waves with maximum pressures ranging from tens to hundreds of kilobars. On the basis of the equations for the flow of mass, momentum, and energy through a stationary shock front, the macroscopic stress-strain curve for the resulting shock deformation can be calculated within narrow limits from the experimentally determined Hugoniol curve. In relatively weak shocks which are preceded by an elastic wave, the stress rises above the clastic limit only as plastic deformation proceeds cold thus the shock has a long toe. In strong shocks that override the elastic wave a high stress is applied without prior plastic deformation. A more important effect of increasing the shock pressure is the generation of shear stresses, called supercrilical shear stresses, that exceed the strength of the perfect lattice. A change in the mechanism of deformation is expected to result from the onset of supercritical shear. The shock disordering of ordered Cu3Au in strong shocks appears to be an example of such a change. It is suggested that the formation of fine twins in copper and nickel and the formation of structures which enable visible twins to be formed in the rarefaction ware, observed in copper and presumably in disordered Cu3 Au, are related to the occurrence of supercritical shear in shock dcformation. In recent years several studies1,2 have been made of the changes in structural and mechanical properties of metals produced by the passage through the metals of strong shock-compression waves ranging from about 50 to 800 kbar pressure. Recent work involving dynamic measurements of the shock compression "Hugoniot" curves 3-8 of many metals has developed techniques and provided data required to obtain the shock pressure and the (transient! plastic deformation produced in the shock-conlpression experirnents.9 Shock deformation has been found to be much more effective than slow deformation in changing the mechanical properties of metals, when the two are compared on the basis of equal plasti strain, Holtzman and Cowan9 made quantitative estimates of the shearing stress occurring in a shock front in a metal by assuming that the shearing stress is similar to that occurring in a shock front in a viscous, heat-conducting fluid, with the addition of a yield stress. Taylor&apos;s solution9 for a weak shock was used to estimate pairs of values of shearing stress and thickness of the shock front obtained by assumed choices of the ratio of effective kinetic viscosity to thermal diffusivity. It was noted from these values that. unless the shock front is extremely thin. heat conduction has slight effect, and the shearing stress is nearly independent of the mechanism of deformation. This mechanism does, however, determine the thickness of the shock front and the rate of strain. Furthermore, since the maximum possible shearing stress occurring in shocks of moderate strength does not greatly exceed the shear stress occurring in conventional slow deformation, the mechanism of deformation is not expected to be qualitatively different. The greater effectiveness of shock deformation in changing the mechanical properties of metals can be attributed partly to the fact that dislocations, when driven by near-conventional stresses, cannot keep up with the shock front, thus necessitating a higher dislocation density than required for an equivalent slow strain. The fast uni-axial strain occurring in the thin shock front would also be expected to cause a larger number of dislocation intersections to occur. In the upper range of shock pressures that have been studied the estimated values of the shearing stress exceeded the estimated shear strength of a perfect crystal. Under these circumstances it is reasonable to expect that the mechanism of deformation might be considerably different from that involved in slow deformation. Except for the observation by smith1 of twins in shocked copper, the effects of shock waves on metals did not show any obvious or large changes in properties that would indicate the onset of a change in the mechanism of deformation. The recent investigation of the effect of shock waves on ordered and disordered specimens of Cu3Au by Beardmore, Holtzman, and ever" showed a spectacular decrease in the amount of long-range order retained by initially ordered Cu3Au when the shock pressure was raised from 290 to 370 kbar. Since Dr. Holtzman and I suspected that this behavior probably was due to the onset of a shearing stress in the shock front in Cu3Au which exceeded the limiting shear strength of the perfect crystal. it was considered appropriate to examine directly the shock-front equations for a solid. and to obtain a sound estimate of the shearing stress occurring in the front using equation of state data obtained from shock studies. In this paper an estimate is made of the

Jan 1, 1965

By G. A. Moore

A brief review is given of methods designed to produce metallic iron of high purity, and typical results are listed. A recent method, utilized at the National Bureau of Standards, consists of the extraction of ferric chloride by ether, reduction of this ferric chloride to ferrous chloride, further purification of this chloride, and the subsequent electrolytic deposition of metallic iron. iron produced by this procedure apparently is softer than, and otherwise different in properties from, any iron previously prepared and contains appreciably smaller amounts of impurities. THE history of attempts to produce "pure" iron reaches to antiquity and it may be presumed that each ancient armorer who succeeded in making a better steel concluded, correctly, that he had done a better job of removing the "base metals," and incorrectly, that he now at last had a "pure" metal. Early metallurgical papers mentioned use of "pure iron" in making alloys—this "pure" iron in most cases being inferior to some commercial stocks of the present time. Improvement has been continuous, and usually at a sufficient rate to convince each succeeding group of workers that they, at last, were using the really pure metal (until the analysts also improved their techniques to again discover the impurities). These adventures were reviewed in some detail by Cleaves and Thompson.&apos; Although the ores of a metal may be abundant, difficulties in extracting it may make the pure metal very rare. When impurities are restricted to a total of a few parts per million, nearly all pure metals become rarities. Lead, copper, gold, mercury, silver, zinc, aluminum, bismuth, and the six platinum metals are claimed to be available with total impurities ranging from 2 to 50 ppm. The present small and scattered world supply of so-called "pure" iron holds an unimpressive place in another group of 16 metals having approximately 100 ppm of foreign material. Of about 20 less rare metals, only the platinum metals are more costly to prepare. While the production of such rare varieties of iron may appear insignificant in the presence of thousand-ton operations with 95 to 99 pct metal, it must be emphasized that all researches on commercially interesting irons and steels are in fact studies of the modifications of the properties of iron by additional materials. Until the properties of high purity iron are directly measured, all ferrous research must operate without known base values. Traces of impurities may affect the properties of a metal in many ways. Infinitesimal traces of solutes, by disturbing the electronic configuration, greatly change the electrical properties of transistors and semiconductors2-3 and slightly larger traces might alter these quantities in iron. Soluble impurities which disturb the perfection of lattice arrangement not only may alter the magnetic constants and electric properties, but by their close association with dislocation phenomena probably control the very existence of the "yield point"; determine the value of yield stress; and perhaps control the selection of slip and cleavage planes. It has been speculated that impurities might even cause the allotropic transformation in iron, but in any case their rearrangement must contribute to the unreliability of heat capacity and other thermodynamic measurements. Impurities which do not remain in solution may cause even greater effects on the properties. Microscopically visible amounts of phases other than ferrite can be found in all high purity irons which have come to my attention. It can be calculated that from 50 to as little as 2 ppm of an insoluble material might be sufficient to completely film all grain boundaries in irons having grain sizes from ASTM Nos. 10 to 1. Should this occur, such films, even though invisible, may be very important in fracture problems, especially at extremes of temperature:&apos; Studies of grain growth and diffusion normally imply consideration of a single-phase system, hence, in the presence of insoluble impurities they can be expected to give ambiguous data." High purity iron is also in demand for use as chemical and spectro-chemical standards; for work in classifying the lines of the iron spectrum; for biological work in nutrition; and for work in nuclear physics. where the presence of some sensitive

Jan 1, 1954

Jan 12, 1950

By Robert W. Phelps

It is gratifying to observe the growing interest in the study of oil-well spacing. It should always be held in mind that the problem of optimum spacing is to obtain the maximum return of capital per acre drained. This naturally evolves.into a mathematical consideration. As mathematics is the basis of all science, an effort should be made to develop formulas which involve data obtainable in the early stages of development. The first information from a discovery well in a new field would be the character of the sand, rate of initial production of oil and gas, viscosity of the oil, rock pressure, etc. Later, from this well, if Herold&apos;s theories of hydraulic, volumetric and capillary controls are accepted, could he determined the ultimate production as without interference from drainage by subsequent well completions, and under which control the well is producing. If it should prove to be producing under capillary control, a rough estimate could be made of it&apos;s radius of drainage. With but one well, the radius of drainage, or the interference of drainage of individual wells by close spacing, would be estimated by comparison with similar conditions in other fields in which the development has progressed sufficiently to furnish the data. A second well that is spaced sufficiently close so that an interference can he observed after its ultimate production is estimated, will furnish data to develop a desirable spacing of wells which can be inaugurated for that area and which is capable of producing a uniform amount of oil under like conditions. In some fields this area will be extensive, in others each well location will require an individual study. In 1924, Cutlerl developed a scheme whereby he determined by tabulation a spacing of oil wells for the maximum return per acre. After a study of production in a number of fields, he developed the following as a tentative rule: "The ultimate production for wells of equal size in the same pool where there is interference (shown by a difference in the, production decline curves for different spacing) seems approximately to vary directly as the square roots of the areas drained by the wells. This rule may also he stated thus: The recovery from wells of equal size

Jan 1, 1929

By H. R. Brannon, F. M. Perkins, Weldon O. Winsauer

Both the abnormal resistivity exhibited by shaly reservoir materials and their potential are due to adsorption of ions. Interrelationships between the two have been derived and verified by laboratory results. These relations which have resulted from this work may be used in a qualitative manner to estimate whether or not a particular shaly reservoir contains hydrocarbons, and also to estimate the porosity of shaly sands. INTRODUCTION In spite of the progress which has been made in the last decade toward a better understanding and utilization of the electric log, there remain a number of problems in the interpretation of the log. One of these which is often troublesome is that of divining the nature of the fluids in sandstones or carbonate rocks which contain appreciable amounts of shale. It was shown by Patnode and Wylliel in 1949 that shaly rocks exhibit an abnormally low resistivity when saturated with solutions of low ionic concentrations. This phenomenon has been demonstrated to be due to the adsorptive properties of shale or clay in the rock.&apos; In estimating the fluid content of shaly sands or carbonates from the electric log, it is desirable and sometimes necessary to correct for the abnormally low resistivity. A similar correction is likewise often necessary if attempts are made to estimate the porosity of a stratum from resistivity measurements. The correction may be made from data obtained on core samples and from information on salinity of interstitial water. Cores, however, are not always available. Moreover, even if cores are at hand, their examination is time-consuming. It would be most desirable, therefore, to make corrections of this nature from the log itself. Since both the abnormal resistivity and the potential&apos; are consequences of the adsorption of ions on shale, it should be possible to utilize the potential curve to give better interpretation of resistivity data obtained in logging shaly materials. The work described in following sections was directed toward this end. THEORY Relation of Resistivity of Shaly Reservoir Rock to Adsorpttve Properties In discussing the effect which the presence of shale or clay exerts on the resistivity of a reservoir rock, it is convenient to make use of the resistivity factor.4,5 This quantity has been defined as the ratio of the resistivity of the rock when it is completely saturated with an electrolyte to the resistivity of the electrolyte itself. When the rock, such as a clean sand or carbonate, is free of shale the resistivity factor is virtually independent of the ionic concentration of the electrolyte used to saturate the sample, so that F = R0/Rw = constant for a clean rock . . (1) where F is the resistivity factor, R0 is the resistivity of the rock saturated with electrolyte, and Rw is the resistivity of the electrolyte. When the rock contains argillaceous material, the resistivity factor as defined above is no longer independent of the concentration of the electrolyte used to saturate the rock, but decreases as the ionic concentration of the electrolyte decreases. In explanation of this behavior, it is instructive to consider a sample of shaly porous rock placed in contact with a large volume of a dilute electrolyte. The sample is considered to become saturated with the electrolyte, and to attain equilibrium with it. As a result of adsorption by the shale surfaces within the rock, there is a greater concentration of ions in the solution adjacent to the shale particles in the interstices of the sample than there is in the external solution with which the

Jan 1, 1955

By K. Thirumalai

Rock response to heating depends on properties of rock material and varies widely between different rock types. By dissipating energy, surface melting limits rapid heating and fragmentation of rocks achieved by surface heating methods. This study advances a concept of rock fragmentation by rapid internal heating of a localized inner volume of rock. The working of the method to achieve fragmentation of rocks (Charcoal granite and Dresser basalt) having poor response to surface heating is analyzed. Experimental data on elevated temperature rock properties required for the study are presented. Based on the properties of test rocks, a high frequency (50 MHz) dielectric heating method of generating localized internal heating was selected for experimental study. The test rocks were fragmented without melting under localized heating below 600ºC. The heated volume required for fragmentation was observed to be less than 2 percent of the test block volume. A practical application of the method for in situ fragmentation of rocks is suggested.

Jan 1, 1971

By Albert F. J. Bordeaux

Discussion of the paper of Albert F. J. Bordeaux (Bi-Monthly Bulletin, No. 23, September, 190S, pp. 629 to 640). A. H. BROMLY, Zihuatanejo, Guerrero, Mexico (communication to the Secretary*) :-The following criticism of what "is offered as a summary which may be found useful by mining engineers," is not dictated by any captious spirit, but in the interest of historical and scientific accuracy. The States of Queretaro and Oaxaca have produced sufficient silver to warrant more extended notice. Referring to Pachuca, State of Hidalgo, the somewhat loose and. inexact statement is made that "the ore-deposit is an andesite, intermixed with quartz-veins, rich from the surface." A better description would be,-the ore-deposits consist of quartz-veins in andesite. It is notable that many of the rich shoots worked in recent days did not come to surface. In consequence, Pachuca, is often quoted by the ill-informed as a camp in which values improve with depth, the truth being that the veins carry shoots, or clavos, some of which were exposed at surface and some not. The name of " electric plow," applied to the mechanical stirrer of recent use, is certainly not to be recommended. The stirrer, or agitator, consists essentially of a traversing gang-plow, operated by power through shafting, drums, and wire-rope. The fact that in certain plants the motive-power used is electricity does not make it an electric plow. Such a name suggests a machine of which the motor is an essential and integral part; which is not so in this case. A lathe in a factory driven by water-power is not called a hydraulic lathe. My experience agrees with Dr. Raymond&apos;s note as to azulaque, which in sortie districts is also applied to blue copper carbonate. The El Oro, Esperanza, and Mexico mines should be allocated to the State of Mexico; the Dos Estrellas being in Michoacan, as stated. The El Oro quartz certainly does not appeal to me

May 1, 1909

By A. Muan

Liquidus data are presented for mixtures in the ternary system FeO-Fe2O3-SiO2 in equilibrium with a gas phase with O2 pressures ranging from 10-10.9 to 1 atm. Data obtained are combined with previously published data to construct lines of equal 02 pressures and lines of equal CO2/H2 mixing ratios along the liquidus surface. Courses of crystallization of selected mixtures under conditions of constant total composition, constant O2 pressures, and constant CO2/H2 mixing ratios are discussed. PHASE equilibrium studies of silicate systems where iron is one component are complicated by the fact that iron readily occurs in three different states of oxidation: Fe3+, Fe2+, and Fe0. Success or failure in work with iron silicate systems is to a large extent dependent on control of the oxidation state of iron and all investigations therefore must be carried out under carefully controlled atmospheric conditions. Silicate systems containing only strongly electropositive metals (like Na+, Ca2+, Mg", etc.) can, for simplicity, be treated as condensed systems, that is, the gas phase can be neglected and the phase relationships discussed in terms of the phase rule written in the well known simplified form P + F = C + 1. In the case of iron silicate systems, however, the composition of the condensed phases varies with the gas composition, and a complete picture of phase relationships can be obtained only by varying the gas composition over a wide range. In order to understand the phase relationships in the more complicated multicomponent silicate systems with iron oxide as one of the constituents, a knowledge of the ternary system FeO-Fe2O3-SiO2 is essential, since it constitutes a bounding portion of all such systems. It was with this in mind that the present study was undertaken. Previous Work A considerable amount of work has been done on various aspects of the chemistry and metallurgy of systems containing silica and iron oxides. The two bounding binary systems FeO-Fe2O3 and FeO-SiO2" The first attempt to obtain information on phase relationships of iron oxide-SiO, mixtures at different 0, pressures was made by Greig.&apos; Darken" determined the melting points of iron oxide on solid silica under various atmospheric conditions. Darken did not determine experimentally the composition of the melts at liquidus temperatures but discussed very ably the principles involved in applying the phase rule to the system. In a recent study Schuhmann, Powell, and Michal8 determined experimentally the liquidus surface of a portion of the ternary system and combined the new information with data in the literature to construct a phase diagram. Their method was briefly as follows: Homogeneous mixtures with various contents of SiO2, FeO, and Fe2O3 were made up by melting together stock mixtures in various proportions. Samples of the homogeneous mixtures, the compositions of which were determined by chemical analysis, were then heated in platinum crucibles in an inert atmosphere until equilibrium among the condensed phases was achieved. The samples were quenched to room temperature and the phases present determined by microscopic examination. Assuming that no change in composition takes place during the equilibration run in inert atmosphere, the liquidus surface can be determined, but no information is obtained regarding the partial pressures of 0, of the gas phase in equilibrium with the condensed phases. The author&apos;s method, to be described in the next section, permitted the location of points at the liquidus surface as well as a calculation of the corresponding partial pressures of O2. Experimental Method General Procedure: The standard quenching technique was adapted for a study under controlled variable atmospheric conditions. Premelted mixtures of silica and iron oxides in platinum envelopes were held at constant temperature under chosen atmospheric conditions until equilibrium was reached among solid, liquid, and gas phases. The sample was then quenched to room temperature, the phases present identified, and, for the most significant runs, the composition was determined by chemical analysis. The corresponding partial pressure of 0, was calculated from known equilibrium constants of the gas reactions occuring in the furnace atmosphere. Materials: Starting materials were oxides of commercially highest available purity; cp silicic acid was dehydrated by heating to 1350°C for 6 hr and cp Fe2O3 was dried at 400° C for the same length of time. Samples of 10 g were made up by mixing

Jan 1, 1956

By Wm. Terry Siemers, Frank E. Kottlowski, George S. Austin

The value of industrial rocks and minerals produced in New Mexico in 1978 exceeded $227 million. The state ranked first in the nation in production of potash and perlite and was a leader in pumice production. Other commodities with sizable production in New Mexico include barite, caliche, clay, dimension stone, fuorspar, gypsum, humate, limestone, mica, salt, sand and gravel, scoria, and silica sand. Non-metallic resources are distributed throughout the state, but development and exploitation is concentrated in western and southeastern New Mexico. The value of industrial rocks and minerals within the state grew about 9% to more than $227 million in 1978. Continued growth, however, depends on continued demand, exploration, and development.

Jan 1, 1982