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By A. U. Seybolt

In part 111' of this series it was shown that during the selective oxidation of a 3 1/4 pct Si-Fe alloy in damp hydrogen, only silica, (observed at room temperature) as low cristobalite or low tridy-mite or both, was formed as an oxidation product. In some in- „ stances where the film was fairly thin (probably well under 100A) there was some suggestion of an amorphous form of SiO2. The present investigation of oxidation rate showed that the selective oxidation of silicon-iron can be rather complicated, and apparently impossible to rationalize in an unequivocal manner. In some temperature regions, notably near 800" and 1000°C, the data seem to obey the familiar parabolic rate law. However, at intermediate temperatures complications were noted, some of which are possibly due to the order-disorder reaction in the silicon-iron solid solution. IN an earlier report' it was shown that during the oxidation of 3 1/4 pct Si-Fe alloys in H2O-H2 atmospheres only silica films were formed in the temperature range from 400° to 1000°C in hydrogen nearly saturated with water at room temperatures, or at dew points as low as -45°C. In the work to be reported here, some observations are made on the rate of oxide film formation. As in the earlier investigation, electron diffraction patterns generally showed either low tridymite or low cristobalite or both, except for some very thin films. These sometimes showed diffuse rings, presumably due to a very small crystallite size, or in a few cases, diffuse bands probably caused by an amorphous film. EXPERIMENTAL PROCEDURE Vacuum-melted silicon iron made of high-purity materials was rolled into strips 0.014 in. thick, and cut into samples 1/2 in. wide by 1 in. long. Chemical analysis showed 3.2 pct Si and 0.002 pct C. All samples were surface abraded with 600-grit paper, were solvent cleaned, and then placed in an paper,apparatus containing a "Gulbransen type"2 micro-balance. Here the gain in weight of the samples of about 5 sq cm area could be followed as a function of time during the oxidation caused by the water in atmospheres of various controlled water-hydrogen ratios. The water-hydrogen ratios can most easily be described as varying from a dew point of 0°C (PH2O-p^2 = 6.2 x 10-3 , to K (P j -40°C (PH2O/PH^= 1.3 X 10-* Most of the experiments were conducted at the 0°C dew-point atmosphere because drier atmospheres caused so little gain in weight that the accuracy of measurement was poor. Because of this, only the data obtained at PH2O,/P,,,= 6.2 x X3 will be reported. The temperature range extended from 800" to 1000°C; and most of the oxidation runs lasted for about 24 hr. The reproducibility of any reading was about ± 1 ?, but the sensitivity of the balance was about 0.2 ?. The atmosphere, flowing at 200 cm per-min, was preheated to the furnace temperature before contacting the specimen. While the gas flow caused a measurable lift on the sample, it was ordinarily sufficiently constant so that it was not an appreciable source of error. X-ray and electron diffraction checks of the samples before and after oxidation showed no evidence of preferred orientation, either on the metal samples or on the silica films formed. EXPERIMENTAL RESULTS The data obtained are summarized in Table I, and some are given in detail in Figs. 1 to 4. In the fourth column of Table I, kp refers to the parabolic rate constant in the expression (?/cm2)2 = kpt + c [1] where ? = micrograms gain in weight kp = parabolic rate constant in units r2 /cm4 t = time in minutes c = constant It will be noted that in many cases no value for kp is given; this is because in these instances the data did not obey the parabolic rate law. The silica film thicknesses given in the last columns are values calculated from the weight gain, an average tridy-mite-crystobalite density, and by assuming a perfectly plane surface. Fig. 1 shows the data plotted in the form of Eq. [I], hence a linear plot indicates parabolic behavior. It has been frequently observed in the literature that

Jan 1, 1960

By WALTON H. HAMILTON

THE demand for "production control" has, like the poor, been with us always. With the development of the nation, the accumulation of business experience, and a maturing understanding of how our many and varied industries work, it is increasingly evident that an uncontrolled output is a source of great mischief and that order and performance demand a control of production. To see clearly the demand for "production control" we must look in detail at the ways in which industries operate. General pictures, grand aggregates, situations as "wholes," and smoothed curves are likely to be deceptive. An industry may seem to keep the even tenor of its ways, and yet the establishments which made it up may experience a great range of fortunes. A nice bundle of statistics may show in the aggregate a lovely regularity which is not shared by the firms which make up a trade. An industry may appear to be reasonably profitable, and yet the profits may be very unevenly distributed. The people in an industry, and dependent on it, are managers, laborers, stockholders, creatures of flesh and blood, such as you and I. General pictures and abstract statements must not blind us to what is happening to firms, corporations and individuals.

Jan 1, 1929

By T. W. Atkins

ATHOUGH the magnesium industry in this country is about thirty years old, not until American industry began to amaze the rest of the world and confound our enemies with the extent and variety of our war production did the industry begin to come into its own. At the outset of the war, only three companies were producing and fabricating magnesium in this country. Today, about sixty companies are producing, casting, forging, extruding, rolling, and stamping this lightweight champion of metals. Experience in alloying, processing. and fabricating the metal gained during the war years is now being translated into hundreds of civilian peacetime applications. In no sense should magnesium be considered as a substitute for other metals. It has come into popular favor because If many unique properties in addition to is being the lightest known structural metal. These attributes are toughness, igidity, corrosion-resistance, and the ease with which it can be machined and worked. Magnesium is the third most abundant element in nature. Sea water, magnesite,

Jan 1, 1946

By James S. Baker

LARGER than continental United States but with only about one third the population, Brazil is a land of enormous potential wealth, waiting to be developed. During a recent visit to that country I saw Brazil at war and learned about some of the recent mineral developments. Many engineers and geologists have been sent to Brazil by various U. S. Government agencies to assist the Brazilian producers and co-operate with the Brazilian Government in producing needed war minerals. The Foreign Economic Administration staff of engineers has been active and through their assistance to the Brazilian producers, steadily increasing quantities of strategic minerals were provided to aid the United Nations' war effort. Mineral wealth has been found in almost every state of Brazil. Many mineral deposits have been discovered during the war period. Examples are: barite near Bahia; the tungsten and molybdenum deposits in Rio Grande do Norte; and corundum, beryl, and tungsten ores in Ceara.

Jan 1, 1945

By E. A. Anderson, M. L. Fuller

The copper-zinc phase equilibrium diagram has been the subject of many investigations. Until recently, however, the boundary of the terminal solid solution of copper in zinc (eta) has not been thoroughly investigated. This paper reports determinations of the solid solubility of copper in zinc at temperatures from 100' to 400' C., the course of the liquidus and solidus for the eta solid solution and determinations of the peritectic temperature and peritectic point for the reaction between epsilon and the melt to form eta. The liquidus of the eta phase was determined by thermal analysis and the solidus by the microscopical examination of specimens quenched from temperatures above and below the solidus. The temperature of the peritectic horizontal was obtained by thermal analysis and the composition at the peritectic point was determined by extrapolation of the solid solubility boundary of the eta phase to the peritectic horizontal. The solid solubility boundary of the eta solid solution was investigated very carefully. Particular care was used to achieve equilibrium in the alloys at each temperature selected. The X-ray, electrical conductivity and microscopical methods mere used in determining the solid solubility limits. The X-ray method measures the changes in the solvent lattice with increasing solute content and in this manner locates the composition of the alloy at which no further change in the solvent lattice takes place, the limit of solid solubility. The method of electrical conductivity measures the conductivity of the alloys of a graded series of compositions, whereby the solubility limit is indicated by a discontinuity in the conductivity-composition relationship. The microscopical method distinguishes, by direct inspection, between the homogeneous solid solution alloys and those having a secondary constituent in addition to the solid solution phase, and thus indicates from the examination of a series of alloys the solid solubility limit.

Jan 1, 1934

By H. J. Levinstein, H. J. Guggenheim

RbFeF3 is a transparent ferromagnet with a large faraday rotation which permits the direct observation of magnetic domain structures in bulk crystals. If the position of dislocations within the crystal were known a study of domain wall dislocation interactions would be possible. In this paper an etch pitting solution is described which gives a one-one correspondent between the etch pits and the dislocations intersecting the (100) surfaces of RbFeF3 crystals. In addition, RbFeF3 is shown to have sufficient plasticity so that known arrays of dislocaticms can be put into the crystal. It is concluded that RbFeF, is an ideal material for the investigation of domain wall dislocation interactions. THE influence of lattice defects on the motion of domain walls in ferromagnetic materials has been studied extensively both theoretically and experimentally.4 The experimental data obtained has been qualitative in nature due to the lack either of a quantitative knowledge of the magnetic domain array in the material or of the nature of the dislocation configuration in the material. At room temperature RbFeFJ has the cubic perovskite structure. It is ferromagnetic below 86°K.5,6 It is also transparent and has a large faraday rotation in the magnetic state.7 The domain structure of this material is observable in three dimensions in crystals which are millimeters in thickness.' Since RbFeF3 satisfies the requirements of having an easily visible three-dimensional magnetic domain structure, it was of interest to determine if the dislocation structure of the material could be determined and if the material was sufficiently plastic so that dislocations could be introduced into the as grown crystals. This is a report of the results of that investigation. EXPERIMENTAL PROCEDURE The crystals of RbFeFs used in this experiment were grown by a technique described elsewhere.5 In order to obtain flat strain-free surfaces, the samples were first cut to the crystal orientation desired and the surfaces were polished by employing standard metallographic techniques. The samples were then immersed in a solution of 1 to 3 g of KOH in 100 ml of water. This solution removes the damaged surface layers uniformly leaving a film on the surface of the sample. Etch pits are obtained by immersing the sample in an approximately 50-50 solution of 30 pct peroxide and concentrated acetic acid. The film formed during the KOH treatment turns deep red in color in the etching solution and flakes off the sample. The etching time required depends upon the pit size desired and

Jan 1, 1970

By Wilbur T. Stuart

TO assist the mining industry in attacking problems of water control, the U. S. Geological Survey has begun a program of research in mining hydrology. In certain fundamental respects water control is similar to development of water supplies from wells or to the drainage of agricultural lands, as many of the tools developed in recent years for quantitative ground-water problems are applicable, with modification, to mine-water problems. In 1952 a 30-day pumping test conducted jointly by the Eureka Corp. Ltd. and the Defense Minerals Exploration Agency provided an opportunity to gain knowledge concerning water movements around a flooded mine shaft. The methods of analyzing the data may be used as a guide for the evaluation of similar problems elsewhere. The Fad shaft of the Eureka Corp. is on Ruby Hill, 1 1/2 miles west of Eureka, Nev. The shaft was completed at a depth of 2465 ft in November 1947 at a site adjacent to the downfaulted block in which the ore was found. As the drift on the 2250 level progressed toward the ore zone, a large flow of water was encountered after the Martin fault was intersected. This flow exceeded the installed pump capacity, and an unsuccessful attempt to recover the shaft and the 2250 level was made in 1948.1, 2 Geology and Hydrology: The complex structure of Ruby Hill is that of an anticline broken first by thrust faulting and later by normal faults. The present orebody comprises several mineralized zones within a block of the Eldorado limestone of middle Cambrian age which was downfaulted 1400 to 1600 ft, and it may be related to a similar body mined at a higher level south of the Ruby Hill fault. At the depth of the largest zone of ore the block is roughly rectangular in shape, about 1000 ft wide and 1500 ft long, and dips about 30" NE, see Fig. 1. It is apparently bounded on the south by the Ruby Hill fault, on the east by the Jackson fault, on the north by the Martin fault, and the west by the Bowman fault. Within the block, but between the Ruby Hill and the Martin faults, are the Office and Adams Hills faults; west of the block and the Bowman fault are the Albion and Spring Valley faults. There are many conflicting reports concerning the water-yielding characteristics of the Eldorado limestone and the condition of the fault zones, that is, whether they are open or tight. However, the diamond-drill records indicate that open spaces as much as 2 or 3 ft across were encountered, and considerable cementing and lining of holes was necessary to maintain circulation of drilling fluid. There is also evidence that the Eldorado limestone was cavernous where it was mined in the early days south of the Ruby Hill fault. At the site of the Fad shaft the formations encountered from the surface down included the Pogonip limestone, Dunderberg shale, Hamburg limestone, and Secret Canyon shale. These formations did not yield large quantities of water to the shaft. The Pogonip limestone, which appears to be permeable and might yield water elsewhere, is above the water table in the vicinity of the shaft. The Secret Canyon shale, immediately overlying the Eldorado in some places but in most places separated from it by the Geddes limestone,3 is apparently tight and does not transmit water. During the 30-day test period the shale briefly confined the water in the underlying formations so that artesian conditions were observed in drillholes E and F, which are cased into the Eldorado limestone, whereas unconfined conditions were observed in drillholes B, C, and D, which were open to the shale. The Geddes limestone, which normally lies between the Secret Canyon shale and the Eldorado limestone, was not encountered in the Fad shaft. The Geddes, a flaggy, fractured limestone, is reported capable of yielding large volumes of water. Water stored in the interstices of this thin-bedded limestone within the Ruby Hill fault zone on the 1200 level of the Locan shaft drowned the pumps in 1923 when the Richmond-Eureka Mining Co. attempted to explore the area along the fault. Eldorado limestone was not encountered in the Fad shaft. In the ore-block area the Eldorado limestone was not entirely offset from other water-yielding formations by movement along the Bowman fault; therefore it may be hydraulically connected with the other formations. Adjacent to the Ruby Hill, Jackson, and Martin faults, the Eldorado lies in contact with other possible water-yielding formations. One of these, the Prospect Mountain quartzite, is separated from the Eldorado by thin, sheared, and broken beds of the Geddes within the Ruby Hill fault zone. A limited examination by the author of the Prospect Mountain quartzite in the Richmond mine at a higher level and south of the Ruby Hill fault indicates that the quartzite is poorly permeable. The monzonite mass south of the quartzite would be a further barrier to the flow of water. The poor permeability of this area is substantiated by records of levels at which water was encountered south of the Ruby Hill fault. In view of the normally low rate of ground-water recharge, if this desert area had been permeable, water levels could not have been maintained at altitudes of many hundred feet above the present water table west and north of Ruby Hill. Thus the ore-bearing block of Eldorado limestone is in contact with possible water-yielding rocks on at least two sides, and if the fault zones are possible conduits for water circulation the geologic and hydrologic conditions are suitable for the infinite-aquifer type of analysis as used and modified here. History of Pumping: During sinking of the Fad shaft a maximum pumping rate of 1500 gpm kept the shaft dewatered sufficiently, but in March 1948, after the 2250 level drift passed through the Martin fault into the Eldorado limestone, the pumps and shaft were flooded. Subsequently additional pump-

Jan 1, 1956

By T. T. Read

FOR the second time the Mineral Industry Education Division opened the sessions at the Annual Meeting by gathering at the Engineering Woman's Club, Sunday at 3 p. in., and, in spite of the informality of the hour, with a good attendance of representative men in the educational field. The chairman of the Division, Thomas T. Read, after briefly reviewing some of the more significant events of the past year, introduced H. P. Hammond, professor of civil engineering, Brooklyn Polytechnic Institute, a leading figure in the project of the Engineers' Council for Professional Development for accrediting engineering schools. Prof. Hammond made it clear that the project is not to rate engineering schools but to accredit them; not to arrange them in order of excellence, but to segregate them into two groups, those that are entitled to recognition as genuine engineering schools, and those that are not. About thirty schools in the whole country will presumably fall into the latter class; they are typified by an unnamed institution where the teacher of mathematics bears the title of Professor of Civil Engineering and the man who teaches chemistry that of Professor of Chemical Engineering, and having no engineering instruction except some elementary surveying, but still claiming in its catalogue to be an engineering college. While everyone would like to avoid the necessity of accrediting engineering colleges, it cannot be avoided, since the University of the State of New York, and several other agencies, are already doing it. If it cannot be avoided it is best that it should be done by a qualified agency set up by the national engineering societies, so that the results may command respect and general acceptance. It is for this reason, and this alone, that the accrediting committee of the E. C. P. D. has been set up. It is now ready to begin its task, and during-the coming year it will accredit the schools in two of the seven geographical districts into which the country has been divided, beginning with New England and the Mid-Atlantic States.

Jan 1, 1935

By GUY C. RIDDELL

THE recent purchase by an American investment trust of a substantial block of shares in a British owned Venezuelan copper operation directs attention to mining activities that have been quietly gaining momentum in that country for a number of years. We hear so much of oil work in Venezuela that attention to its metal-mining activities is in most quarters casual. In gold and copper the country has made some interesting mining records, and two of the old districts are ,digging in for a come-back. Copper Copper production centers in the state of Yaracuy. The Aroa-Cumaragua mining region has had a long and eventful history. The Aroa mine itself, 50 miles from the coast in West-Central Venezuela, was discovered in 1605. First mined in 1632, owned at one time by Simon Bolivar, it has been reopened many times and is now , the basis of substantial operations by the South American Copper Syndicate, Ltd. of London. The latter has operated the property profitably, off and on, for a number of years, paying heavy dividends on a small investment-at times over 300 per cent annually.

Jan 1, 1929

By N. J. Grant, D. Carne, J. B. Seabrook

IT is unnecessary to review much of the literature on hydrogen embrittlement of steel since several excellent reviews and bibliographies exist.1-3 Hot acid pickling and cathodic charging have been known to cause hydrogen embrittlement of steel and have been used as laboratory methods to charge steels with hydrogen.4-8 Experimental Procedure The problem of prime concern in all instances, except in the work of Sims and coworkers,10 is that at no time was there a definite known hydrogen value reported which could be related to a particular value of the degree of embrittlement. It was the purpose of this research to determine the relationship between hydrogen content and degree of em-brittlement quantitatively. The 1020 stock used for the specimens was hot-rolled 7/16 in. diam rod of the following analysis: 0.19 pct C, 0.40 pct Mn, 0.012 pct P, 0.036 pct S' Vacuum-fusion analyses for nitrogen and oxygen gave 0.014 pct O2 and 0.0011 pct N2. Cathodic charging was used to cause embrittle-ment. The advantages of this method were that no quenching was necessary, the impregnation was reasonably controllable, and representative samples for analysis could be prepared simultaneously with the charging of the tensile bars. Analyses for hydrogen were made in a vacuum-fusion type of apparatus which extracted gas from the samples by fusion in a molten tin-iron bath' This apparatus, which has recently been described in detail elsewhere, will not be discussed here.". " Consecutive samples can be analyzed every 15 min with an accuracy of 0'03 ppm. A A from an electrolytic or pickling bath can be charged for analysis in about 3 min, and analysis completed in 15 min. Samples of as-received 1020 stock were analyzed and found to contain a negligible amount of hydrogen (0.06 ppm). Preliminary pickling and electrolytic charging gave highly variable results. Cold-worked samples showed higher values but ranged from 0.6 to 6.0 ppm of hydrogen. Charging at 90°C gave higher values of charged hydrogen, but troublesome films on many of the specimens resulted. It was not until a few drops of a catalytic poison, prepared from 2 g of yellow phosphorus dissolved in 40 ml of carbon disulphide,8 was added to the electrolytic cell that fairly consistent high values of hydrogen could be charged into the as-received 1020 steel at room temperature. The cell used is sketched in fig. 1. The anode and fixture for the tensile specimens were fastened to the cell cover as shown, and the specimen was screwed in place, centrally located with respect to the anode. At first, anodes of lead and graphite were tried, but they contaminated the electrolyte and gave a slight deposit on the specimen. Later, a platinum wire was used in the form of a uniform helix. A current of 2 amp, corresponding to about 0.5 amp per sq in. of cathode, was used for most specimens. The electrolyte was 4 pct H2SO4 solution. Fig. 1 shows the form of the special tensile bar, the main portion of which was an ordinary 1/4 in. diam, 1 in. gauge length test bar, except that two to four small cylinders of stock were left attached by small links to the bottom end of the tensile bar for the purpose of providing samples for hydrogen analysis. Thus the bars and samples were charged with hydrogen simultaneously and an analysis could be made while the bar was being tested mechanically. Experiments were performed to determine how representative the test cylinders were of the middle of the test bar proper. While the bar center was being analyzed, the small cylinder was stored in dry ice, since it had been shown that such storage prevents loss of hydrogen for many hours.12 The results of these checks are shown in table 1. The checks are very good (0.3 ppm) and indicate that it is permissible to use the small end cylinders to establish the hydrogen content of the tensile test bar proper-

Jan 1, 1951

By C. R. Wohrman

A melt of pure electrolytic iron with about 0.4 per cent. sulfur and 7 per cent. manganese was prepared in connection with a study of inclusions in iron. The alloy darkened rapidly when etched with a 10 per cent, alcoholic solution of nitric acid, and microscopic examination revealed the presence of a semimartensitic, semi-Widmanstättian structure (Figs. 1 and 2) closely resembling the structures found by Benedicks in his artificially prepared "meteoric iron."' The structures found by Benedicks were readily explained by the presence in his alloy of the two well-known iron-nickel solid solutions, taenite and kamacite, and of their eutectoid (?) aggregate, plessite. By analogy, one would infer the existence of similar phases in the iron-manganese alloy just described, such an inference being strengthened by the similarity displayed in many ways by nickel and manganese in their effects on iron. Iron-manganese Alloys are Regarded as Homogeneous Heterogeneity of iron-manganese alloys has not been recognized heretofore, judging from the data of standard metallographic books and those of original papers. In fact, iron and manganese are quite generally regarded as completely miscible in the solid state. Dr. Rosenhain,2 for example, writes: Alloys of group (a), of which those of gold-silver, iron-manganese, and copper-nickel are examples, when allowed to crystallize sufficiently slowly to attain their condition of final equilibrium, present a microstructure exactly similar to that of a pure metal—the homogeneous character of the molten solution is in that case so completely maintained that the microscope cannot detect the presence of any second constituent. Guillet and Portevin3 refer to the iron-manganese system as an example of the "case of metals completely miscible in the solid state."

By Richards J. W.

J.W. RICHARDS, South Bethlehem, Pa. (communication to the Secretary?).-Mr. Howland's paper, data and conclusions have interested me intensely, and have led me to study carefully the record-of his 26 furnaces therein given. Mr. Howland is undoubtedly right in his conclusion that when expressing the amount of carbon burned at the tuyères in percentage of the total

Jan 1, 1917

For more than 100 years, the Republic of Chile has been one of the leading copper-producing countries of the world. Between 1877 and 1880 Chile accounted for over 50 pet of total world copper production. Today it has the world's largest known reserves of copper ore and a capability of producing over 600,000 tons per year. This capacity can and will be increased as the world demand for copper grows steadily during the remaining years of this century. The Potrerillos mine of Andes Copper Mining Co., a subsidiary of The Anaconda Co., was developed in the rugged, high Cordilleras in the early 1920's, and the townsite, concentrator, leaching plants, smelter, railroad, power and port facilities were completed so that it came into full production in 1927. Since then and until the closing o f the mine in June of last year, 1,762,192 tons o f copper were produced.

Jan 4, 1960

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 AIME AIME

AN unusually interesting meeting devoted to the discussion of the ways and means of improving coal mining practice, through the larger use of machinery underground, was held in the Auditorium of the Engineering Societies Building on March 11. The meeting was organized by the Materials Handling Division of the A. S. M. E. and held under the auspices of the Metropolitan Section of that Society and the National Coal Association. The New York Section of the A. I. M. E., which had been invited to participate, found itself unable to do so formally because of a conflicting date for its March meeting but informally did its part to aasure the success of the meeting. As a result of the discussion at and preceding the meeting, the National Coal Association, through Walter Barnum, chairman of its research committee, has asked the A. S. M. E. and A. I. M. E. to join the Association in a study of the present problems of the bituminous coal industry. Messrs. Harry L. Gandy, Calvin W. Rice and H. Foster Bain have been selected to act as a committee which shall develop plans for a joint program.

Jan 1, 1926

By Albert E. Wiggin, Frederick Laist

Page I. Introduction............................470 II. The Sources and Amount of Slime................470 II. The Composition of the Slime..................471 IV. The Experimental Development of the .Anaconda Slime Plant.. 471 1. The Great Falls Slime Plant and Experimental Work......471 2. The Experimental Work Done at Anaconda..........473 (a) SlimeThickening Devices.............. 474 (b) SlimeConcentrators................. 475 (c) Dewatering the Slime Plant Concentrate......... (d) The Use of Chemicals to Accelerate the Settlement of Slime........................ 478 (e) The Effect of Temperature upon the Settlement of Slime 478 V. A Description of the Anaconda Slime Plant........... 479 1. A Diagrammatic Flow Sheet of Plant............. 480 2. The Slime-Thickening Division................ 480 3. The Concentrating Division.................. 481 4. The Concentrate-Dewatering Division............. 483 5. General Data........................ 484 I. IntRoduction The new slime-concentrating plant at the Washoe Reduction Works, Anaconda, was put into operation during March, 1914. This plant, which has a capacity of 26,000,000 gal. of slime pulp carrying 2,500 tons of solid matter per day, consists of Dorr thickeners and Anaconda multiple-deck slime concentrators. This plant is the culmination of a great deal of experimental work extending over a considerable period of time, which , work will be described briefly in the following pages. II. The Sources and Amount of Slime Up to the beginning of this year, the ore from the Anaconda company's mines in Butte, Mont., has been concentrated both at the Great Falls

Jan 1, 1915

By W. T. Cardwell, R. L. Parsons

This paper discusses the practical problem of estimating a single equivalent permeability for an oil reservoir, or a portion thereof, whose actual permeability varies in an irregular manner. Limiting averages for general types of permeability variation are developed, and illustrated by examples involving important, specific types of variation. Introduction The theory of the flow of fluids through porous media1"4 is becoming increasingly important in predictions of oil-reservoir behavior. In practical applications, however, reservoirs are seldom found to which simple theory strictly applies. Actual reservoirs have complicated shapes and nonuniform permeabilities and porosities. This paper discusses the problem of estimating a single equivalent permeability for an oil reservoir, or a segment of an oil reservoir, whose actual permeability varies in an irregular manner. The equivalent permeability of a reservoir segment is defined as the permeability of a homogeneous segment of the same dimensions that would pass the same flux under the same pressure drop- It is the permeability value that can be used in simple theoretical formulas to calculate the reservoir behavior. To the authors' knowledge, previous theoretical calculationst on systems of nonuniform permeability have been carried out only by Muskat'"; and he has not dealt with irregular variations, except in writing down the general differential equation for the pressure in variably permeable systems.lb In practical work, many calculations necessarily have been made to estimate equivalent permeabilities from the permeabiiity profiles obtained by core analyses. Regarding such calculations, Johnston and Sherborne6 say: Simple arithmetic and weighted averages have been tried on many wells and it has been found that, where frequent sampling has occurred, the arithmetic average is as satis- factory as a weighted average. It is possible that the application of statistical methods to the analysis of permeability data as recently presented by Law8 may prove fruitful. L,, has made a valuable contribution in showing how statistical analyses may aid in picturing the characteristics of a reservoir from those of a necessarily limited number of core samples. It is believed however that the particular problem of the estimation of equivalent permeabilities can be most directly approached from a fluid dynamical viewpoint as given in the present paper. An example is presented of the use of the conclusions herein in conjunction with Law's method. Theory In order to approach the problem of heterogeneity simply, it is interesting to consider a square block composed of four smaller, homogeneous, square blocks of porous medium, two of which have a

Jan 1, 1945

By G. Derge, Lo Ching Chang

The chemical and physical propertties of slag systems are of special interest to metallurgists, for nearly all metals are in contact with molten slags during the primary reduction from their ores and then during the subsequent refining and alloying processes that determine their ultimate use. These processes are carried out at high temperatures and involve such complex chemical systems that funda-mental scientific knowledge of the Properties and behavior of these slags is inadequate. Various hypotheses have been Proposed to explain known slag characteristics. The commonest of these regard the molten slag as constituted of compounds that are dissociated in varying degrees into their constituent oxides, as illustrated by Schenckl and the recent Papers of Chipman and co-authors. Another proposal is that these compounds dissociate by com-plete6 or partial ionization, the evidence for which has been reviewed by Martin and Derge.? whatever hypothesis is favored, the exact formulation of these compounds is incomplete. It is based on three principal types of information: 1. Studies of solidified 51% samples by X ray diffraction, petrography, and similar methods that can be used at room temperature. The correlation of this information with the high-temperature properties of the molten slag is uncertain. 2. Studies of slag-metal equilibria, which have the advantage of providing observations on the molten slag at high temperature. However, even these data present problems of interpretation because they require a complete knowledge of the metal phase. 3. Direct measurements of properties of molten slag at the temperature of greatest metallurgical interest. Viscosity, electrical conductivity, specific heats, and similar properties have been measured, but the data of this type are widely scattered and frequently difficult to interpret. Additional direct measurements of properties of molten slag that can be interpreted in terms of chemical behavior are required, and this paper shows that the standard physical-chemical measurement of reversible electrode potentials, which measure the activity of specific constituents, is a fruitful source of such information. The purpose of this investigation, therefore, was to find an electrode combination that would yield reversible electromotive force measurements when dipped into the molten slag to be studied. Slags of the systems cao-sio2 and cao-120,-SiO2 were chosen for study because graphite containers could be used and the data could be correlated with those for viscosity, conductivity, and other proper-

Jan 1, 1948

By G. Derge

The chemical and physical propertties of slag systems are of special interest to metallurgists, for nearly all metals are in contact with molten slags during the primary reduction from their ores and then during the subsequent refining and alloying processes that determine their ultimate use. These processes are carried out at high temperatures and involve such complex chemical systems that funda-mental scientific knowledge of the Properties and behavior of these slags is inadequate. Various hypotheses have been Proposed to explain known slag characteristics. The commonest of these regard the molten slag as constituted of compounds that are dissociated in varying degrees into their constituent oxides, as illustrated by Schenckl and the recent Papers of Chipman and co-authors. Another proposal is that these compounds dissociate by com-plete6 or partial ionization, the evidence for which has been reviewed by Martin and Derge.? whatever hypothesis is favored, the exact formulation of these compounds is incomplete. It is based on three principal types of information: 1. Studies of solidified 51% samples by X ray diffraction, petrography, and similar methods that can be used at room temperature. The correlation of this information with the high-temperature properties of the molten slag is uncertain. 2. Studies of slag-metal equilibria, which have the advantage of providing observations on the molten slag at high temperature. However, even these data present problems of interpretation because they require a complete knowledge of the metal phase. 3. Direct measurements of properties of molten slag at the temperature of greatest metallurgical interest. Viscosity, electrical conductivity, specific heats, and similar properties have been measured, but the data of this type are widely scattered and frequently difficult to interpret. Additional direct measurements of properties of molten slag that can be interpreted in terms of chemical behavior are required, and this paper shows that the standard physical-chemical measurement of reversible electrode potentials, which measure the activity of specific constituents, is a fruitful source of such information. The purpose of this investigation, therefore, was to find an electrode combination that would yield reversible electromotive force measurements when dipped into the molten slag to be studied. Slags of the systems cao-sio2 and cao-120,-SiO2 were chosen for study because graphite containers could be used and the data could be correlated with those for viscosity, conductivity, and other proper-

Jan 1, 1948

By Thomas T. Read

AT this time of the year, engineering schools are releasing a group of young men who probably are, on the average, in much the same attitude of mind as a person arriving at the terminal station of a railway journey; namely, of having a general idea of his objective, but having to make a decision as to just where he is going and how best to get there. The man leaving the train can at first follow the crowd, but it soon breaks up, as one goes one way and one another, until he has to choose his own course. The recent graduate may do the equivalent of following the crowd by accepting the first position offered, but this only postpones a decision as to where he is going and how best to get there. So many young engineers ask for advice as to what to do that the following statement has been prepared as an attempt to make a general answer to such queries. The engineer taking his first job should realize two fundamental relations. The first is that in electing to be an engineer he has elected to be a hired man. A consulting engineer has more freedom than a man on a regular pay roll, but he is also a hired man; hired for briefer periods at a relatively high rate, but under the necessity of simultaneously doing his consulting work and developing new retainers. There is nothing derogatory in being a hired man (all doctors, lawyers and clergymen are hired men), but the tardy realization that he is one seems to give many an engineer a mental jolt that can be avoided if he accepts it from the beginning.

Jan 1, 1926