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By Edmund D. North

In making a glass model of mine-workings, each mine will present some little individualities, to meet which will call for the exercise of special ingenuity. Having made several models, I offer the following details of the model of the Montana-Tonopah mine-workings, believing that with small changes for different conditions the method described can be successfully used in making a glass model of the workings of any mine. The model, Fig. 1, has the top, one end, and the front removed. The case is made of kiln-dried pine, painted with several coats of dead-white paint. It is made to take sheets of glass 24 by 42 in. in size, and is 18 in. high, the workings shown being on a scale of 1 in. = 40 ft., or 4800 : 1 scale. The base is made of four pieces of 2-in. material, well pinned and glued together. The back, of material 1 in. thick, is secured rigidly to the base by screws and countersinking. The four posts, 1.5 in. square, are so cut that the front and two ends of the model fit in flush with the outside edges of the posts. The top rails, 1 in. square, are fastened rigidly to the front and back posts by means of small iron braces. The ends, front, and top of the case are of 0.5-in. material; the ends and front are held in place at the bottom by pegs fitting into the base ; at the top the ends are held by buttons and the front by cupboard-hooks on the inside. Hinged hasps on the cover, fitting over staples in the end-pieces, make it easy to lock the entire case. Before the back is fastened to the base, it is cut with horizontal and vertical grooves to receive the horizontal and vertical sheets of glass, shown clearly in Figs. 1 and 2. The horizontal grooves, spaced to scale, represent the vertical distances between the levels at the shaft. The vertical grooves are placed wherever cross-sections of the workings are desired.

Jan 1, 1910

By D. B. Carson, D. L. Katz

Natural gases under pressure form crystalline hydrates with water. Experimental data are reported on four-phase equilibrium for the methane-propane-water, methanc-pentane-water, and methane-hexane-water systems. Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbon-rich liquid, and hydrate were measured, as well as the percentages of methane and propane in the hydrate. The data indicate that natural gas hydrate behaves as a solid solution and that pentanes and heavier hydrocarbons do not enter into the solid phase. Vapor-solid equilibrium constants are presented that permit the approximation of the conditions for hydrate formation, from the composition of a gas. Introduction Natural gas hydrates have been the object of considerable research in recent years, because of the trouble they have caused in the natural-gas and natural-gasoline industries. Natural gas hydrates are white crystalline compounds of water and gas, which, under pressure, exist at temperatures considerably above the freezing point of water. Because of the relatively high temperatures at which the hydrates exist, they become a nuisance in high-pressure gas operations where water is present, since their formation causes partial or complete plugging of valves and pipes. From a practical standpoint, the trouble incident to hydrate formation has been solved by dehydration of the gas before it enters the plant or pipe line, or by other remedial measures. Extensive work on gas hydrates in the latter part of the nineteenth century, by Villardl and others, gave data on methane hydrate and on ethane hydrate. Schroeder summarized these theoretical studies2 Hammerschmidt3 introduced the information on gas hydrates to the gas industry and Dcaton and Frost4-6 gathered a considerable number of data on the behavior of natural gas hydrates. Recent papers7,8 have extended both the data and the theory of these hydrates. At present, data are available on tem-peraturcs and pressures of hydrate forma. tion for pure methane, ethane, propane, n-butane, methane-ethane mixtures, meth-ane-propane mixtures, methane-butane mixtures, and some Is natural gases, all- in the Presence of excess water. However, up to the Present time no method has been available for predicting the temperature at given pressures or the pressure at given at at which natural gases will form hydrates if hydrates with water. 'This Paper Presents data on the methane-propane-water, methane-pentane-water and methane-hex-""e water systems in four phases, one of which is the hydrate. he application of the phase rule to the methane-~ro~ane-water data Proves that hydrates behave as solid solutions. The data of this paper and those in the literature were used to develop vapor-solid. equilibrium constants,8 which permit prediction of conditions of hydrate formation from the analysis of a natural gas.

Jan 1, 1942

By Waldemar Lindgren

Fifteen years ago, in his presidential address before the Washington Academy of Sciences,' Alfred H. Brooks said: "Applied geology can only maintain its present high position by continuing the researches which advance the knowledge of basic principles. Future progress in applied geology depends on progress in pure geology. Early in 1927, Dr. David White, then chairman of the Division of Geology and Geography of the National Research Council, appointed a committee "On the Processes of Ore Deposition," which was the first recognition by the Council of this branch of applied geology. This committee will not be able to solve the many complex problems involved; it can only clear the way, survey the field, state the problems and encourage systematic research. This short paper aims to outline and to analyze the present status of this kind of geological research, to ascertain the quality of the work and to suggest lines that might profitably be followed. Increasing Demand for Geologists Economic geology, or the art of geology, could develop only after the principles of geology and mineralogy had been established. Before that time it was merely a collection of trade rules accompanied by more or less wild speculations. Thus we observe the beginnings of economic geology in the period 1770-1820. Soon afterwards, the State Surveys were established in this country, with the realization that the natural resources should be investigated and described. Geology was hardly yet equal to the task of scientific research in relationships and genesis, however, and there followed a period of discouragement and stagnation. In the meanwhile, pure geology had again registered progress, and, based on its principles and also on the rapid mining development in the Cordilleran region, the present phase of the study of ore deposits began to take form. Raphael Pumpelly, S. F. Emmons and G. F. Becker were among the pioneers in this movement. The United States Geological Survey was organized. Ore deposits were scientifically described and studied along lines of structure and mineralogy; theories of genesis were advanced, not always permanent but based on sound induction.

Jan 1, 1928

By B. Tani, K. Anderson, I. Johnson, R. Schablaske

INVESTIGATION of the various rare earth-cadmium binary systems discloses the existence of a compound corresponding to the composition MCd6 in all systems save the La-Cd system. Lattice constants for all of the MCde compounds, except LaCd6 which apparently does not form, and PmCd6 whose synthesis was not attempted, are also recorded herein. Iandelli and Ferro 1 report the existence of the compound CeCd6. No additional information, structural details, and so forth are given. Elliott and Lemons2,3' have measured the vapor pressure of cadmium over CeCd6 and have calculated the activity of cadmium in solid CeCd6. These authors find that CeCd6 exists over a composition range from 5.967 to 6.098 (Cd:Ce ratio) at 584oC, and from 5.971 to 6.118 at 639°C. The following is an excerpt from the paper by Elliott and Lemons: 2 "Recently Mr. F. H. Ellinger of this laboratory has indexed an X-ray diffraction powder pattern of CeCd6.00 which we had prepared by gas phase reaction. The compound has a primitive cubic unit cell with a = 15.783 + 0.001A Based on the volume of the cubes surrounding an elemental cerium or an elemental cadmium atom, Mr. Ellinger finds room for 24.10 CeCd6 formula units in the CeCd6 unit cell; similar calculations based on CeCd2 and CeCd11 yield 24.18 formula units per unit cell. The presence of 24 CeCd6 units per unit cell seems probable with an X-ray density of 8.255 grams per cubic centimeter. The most one can say about in-terstitial~ is that there appears to be room in the crystal even at room temperature." Measurements of the solubility of the rare earths in liquid cadmium4 led to the discovery of GdCd6,

Jan 1, 1964

By H. A. Buehler

LOCATION THE Ozark region occupies a large part of the southern half, of Missouri, the northern portion of Arkansas and comparatively small areas in northeast Oklahoma, southwest Kansas, and southern Illinois. . It is a roughly elliptical plateau which has been deeply dissected by stream erosion, and which slopes imperceptibly into the prairie regions to the north, east, and west, but which terminates rather abruptly along the Arkansas River on the south and Tertiary lowland to the southeast. The-Boston Mountains extending for a distance of some 200 miles (321 -km.) along the Arkansas River rise to an elevation of 2000 ft. (609 m.), forming the most prominent topographic feature of the region. The so-called St. Francois Mountains in St. Francois, Madison, and adjoining counties in southeast Missouri, form a prominent but more restricted topographic feature, the highest point rising to an elevation of 1800 ft. (548 m.).. The remainder of the region is largely a plateau area varying from 800 to 1500 ft. (243 to 457 m.) in elevation. STRATIGRAPHY The region is underlain chiefly by sedimentary formations, which outcrop in roughly concentric bands around a comparatively restricted area of igneous rocks in the St. Francois Mountain district. Although located geographically near the eastern edge of the Ozarks, the St. Francois Mountains have apparently suffered the greatest orogenic movement and the lowest formations of the succession are exposed in their immediate vicinity. The various sedimentary formations of the region do not show any considerable metamorphism and have suffered little change since consolidation. With the exception of a few basic intrusions in Ste. Genevieve County and a pegmatite dike in Camden County, Missouri, there is no evidence of igneous-action, since the first sedimentary beds were deposited.

Jan 10, 1917

By H. S. Munroe

As elaborate discussion under this heading formed a chapter in one of the reports made by Professor Raymond as Commissioner of Mining Statistics." In a subsequent report? was printed a paper., by Mr. William Main, Jr., of Columbia, South Carolina, containing a theoretical investigation into the effect of the velocity of impact on the effective ditty of stamps. A visit to the Lake Superior copper region last summer suggested an inquiry into the relative efficiency and economy of the enormous steam stamps of the copper-mills, as compared with the results obtained with the cam and tappet stamps commonly used in the West. The atmospheric stomp used at the Phoenix Mill promised to add interest to the inquiry, as giving an example of unusually high speed, this stamp making 160 drops per minute. In introducing his subject Dr. Raymond makes the following remarks, which are quite apropos of the present investigation: "In considering the economical application of stamping machinery, we meet, at the beginning, with serious difficulties in obtaining accurate data for comparison. The weight and fall of stamps vary as the shoes and dies wear out; and this may lead to a change of speed also. Moreover, defects in engines, boilers, or machinery for the transmission of power, may occasion serious losses, which cannot fairly be charged to the arrangements of the stamps proper. Again, the capacity of stamp-mills is directly dependent, in some degree, upon the nature and extent of discharge, fineness of screens, and other peculiarities of the battery. Finally the hardness and tenacity of the rock crushed varies so much that comparisons between different localities cannot be implicitly trusted. The safest experiments are those made in the same mill, by changing first one arid then another condition of working; but this is seldom possible for such

Jan 1, 1881

By A. J. M. Ross

Backfilling of stopes and other underground openings in the Homestake mine with sand tailings was undertaken primarily to reduce surface subsidence, which was wrecking much of the surface plant and a substantial part of the town, and to make possible maintenance of openings into the top of pillar stopes as mining progressed. The progress of this type of filling has been rapid and the results very satisfactory. Sand is now used in filling timbered stopes, shrinkage stopes, and abandoned drifts and crosscuts. A permanent pipe-line system for transporting sand tailings into the mine by gravity has been installed. The close filling of all stopes has resulted in important benefits other than the two major ones. The ore bodies in the Homestake mine occur as replacements in one distinctive layer of the metamorphosed pre-Cambrian sediments along a group of minor folds that together form a complex anticline that pitches at 35" to 40' to the southeast. The ore bodies are extraordinary for their magnitude. Widths of over 300 ft. have been mined and continuous ore has been followed for over 1200 ft. along the strike on some of the upper levels. Mining has been by shrinkage stoping with square-set mining of crowns and pillars. In the standard plan, shrinkage stopes 60 ft. in the direction of strike and the full width of the ore have been taken up to within 25 ft. of the level above. After filling, the crown has been mined by square-set methods, as have also the 40-ft. pillars between shrinkage stopes. In former days, when the supply of ore seemed inexhaustible, the mining of pillars was allowed to lag far behind because of the high cost. Many pillars were rather badly fractured on the level and in some places between levels. Coarse waste was used for backfilling all stopes, but in pillars it became increasingly difficult to maintain haulageways for the transportation of this fill over the top of the stopes as mining progressed. The cost of maintaining these crosscuts was excessive and in many pillars practically impossible. Therefore it became the practice to fill pillar stopes by tapping the back and sides of the stopes.

Jan 1, 1940

By A. B. Kinzel, Walter Crafts

A PRevioUs study1 of the relations of impact strength to inclusions showed that the dynamic strength of steel is lowered by the presence of visible counted inclusions, but that other factors comprised in the term "body" have a marked influence. The previous work was carried out on selected steels from a single source, so that the body factor was purposely minimized, but even under these conditions it was found that inclusion counting or the use of the commercial inclusion rating is not satisfactory. The tensile-impact test, however, was indicated as a satisfactory measure of dynamic strength. It was further suggested that the tensile-impact test should be so standardized as to be suitable for use in specifications, and that the hardness factor should be worked out over a sufficient range to admit ready commercial use of the tensile-impact test. In accordance with these suggestions, and in view of the fact that the steels reported in the previous paper were selected and treated so as to have a minimum variation in body, hardness and structure, further work has been performed on a variety of steels which are not limited by these conditions. The word "body" is used here for want of a better term. It is simply a convenient expression which comprises the effect, of the various unknown factors that modify the dynamic strength of the steel. Thus at our present state of knowledge, the writers have chosen to consider hardness, structure and counted inclusion content as factors not comprised in the term "body," and such factors as raw materials, process of melting, fabricating, etc., as comprised in the term "body." Numerous grades of steels made in several ways have been taken from different sources and have been heat-treated to varying hardness by normalizing and by quenching and drawing. The results, therefore, may be considered to be generally applicable to current engineering steels. A certain limitation with respect to the hardness at which steel should be tested still seems necessary. The upper limit of this hardness range has

Jan 1, 1931

By C Woodward

AT the Belmont mine of the Anaconda Copper Min-ing Co., Butte, Mont., a new double-drum electric main hoist and a single-drum electric auxiliary hoist have recently been placed in operation to meet the demand for greater hoisting depths, and to replace a steam-driven hoist which was inefficient and inade-quate for the new conditions. The ease of operation, safety, and efficient consumption of power of the main hoist all tend toward improved hoisting conditions. It consists of a 2150 hp. d. c. motor, directly connected to a shaft carrying two drums equipped with clutches and brakes. The auxiliary hoist consists of a 1000 hp. d. c. motor directly con-nected to a single drum provided with the necessary brakes. Fig. 1 shows the general arrangement of the complete installation, with idler towers and head-frame. The headframe is built of Bethlehem H and G rolled sections, equipped with two 12-ft. dia. cast steel sheaves for the main hoisting ropes. The sheaves are mounted 129 ft., 6 in. above the collar of the shaft; and above them trolleys are provided for their removal or repairs. Between the headframe and the hoist machinery are two idler towers for supporting the ropes on 3-ft. man-ganese steel idlers provided with roller bearings which fleet on a fixed shaft. As a city street is between- the mine headframe, and hoists, it is necessary to protect the thoroughfare from drippings of the preservative compound used on the ropes which pass over the street. For this purpose, at the point where the hoisting ropes cross the street ,a bridge of trusses, supported on columns and roofed with corrugated iron, is provided from property line to property line. Since one of the idler, towers is set close to the street, a part of the structure is built in-tegral with the street covering. The general design of idler tower as well as the covering over the street is shown at A in Fig. 1.

Jan 9, 1927

By Henry G. Granger

Repeated failures in attempts to work gold-bearing gravels by means of suction-dredges have created the impression that this method is impracticable. The suction-dredges have failed from three special causes: excessive wear and frequent breakage of pump-shell, runners and liners; inability to dredge compact gravel which would not readily move towards the intake; and, most important of all, closing of the suction-pipe by stones too large to enter it. In my opinion, all three causes of trouble may be remedied: the first, by making stronger the parts most liable to wear and breakage; the second, by means for loosening the gravel at the intake; and the third, by sufficiently increasing the diameter of the suction-pipe. In suction gold-dredges, this diameter has not usually exceeded 10 or 12 in.; whereas there are few profitable gold-fields which call be considered dredge-able, in which stones more than 12 in. in diameter are not frequently encountered. II. An Effective Suction-Dredge. In harbor-operations, much larger stones are handled by suction-dredges. The large dredge of the Henry Steers Contracting Co. worked for nearly four years at League Island, Philadelphia, where it sucked up, passed through the pump, and forced through 3,700 ft. of discharge-pipe, gravel containing boulders up to 200 lb. in weight. This was done with no bad breaks and few shut-downs. The cutter and liners were the only parts liable to damage, and these were easily replaced with brief interruption of work. The chrome-steel liners are said to have lasted from six to nine months. I am informed that this dredge worked continously for nine

Jan 1, 1910

By Don B. Carson, Donald L. Katz

NATURAL gases under pressure form crystal-line hydrates with water. Experimental data are reported on four-phase equilibrium for the methane-propane-water, methane-pentane-water, and methane-hexane-water systems. Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbonrich liquid, and hydrate were measured, as well as the percentages of methane and propane in the hydrate. The data indicate that natural gas hydrate behaves as a solid solution and that pentanes and heavier hydrocarbons do not enter into the solid phase. Vapor-solid equilibrium constants are presented that permit the approximation of the conditions for hydrate formation, from the composition of a gas. INTRODUCTION Natural gas hydrates have been the object of considerable research in recent years, because of the trouble they have caused in the natural-gas and natural gasoline industries. Natural gas hydrates are white crystalline compounds of water and gas, which, under pressure, exist at temperatures considerably above the freezing point of water. Because of the relatively high temperatures at which the hydrates exist, they become a nuisance in high-pressure gas operations where water is present, since their formation causes partial or complete plugging of valves and pipes. From a practical standpoint, the trouble incident to hydrate formation has been solved by dehydration of the gas before it enters the plant or pipe line, or by other remedial measures. Extensive work on gas hydrates in the latter part of the nineteenth century, by Villard1 and others, gave data on methane hydrate and on ethane hydrate. Schroeder summarized these theoretical studies.2 Hammerschmidt3 introduced the information on gas hydrates to the gas industry and Deaton and Frost4-6 gathered a considerable number of data on the behavior of natural gas hydrates. Recent papers7,8 have extended both the data and the theory of these hydrates. At present, data are available on temperatures and pressures of hydrate formation for pure methane, ethane, propane, n-butane, methane-ethane mixtures, methane-propane mixtures, methane-butane mixtures, and some 15 natural gases, all in the presence of excess water. However, up to the present time no method has been available for predicting the temperature at given pressures or the pressure at given temperatures at which natural gases will form hydrates if saturated with water. This paper pre¬sents data on the methane-propane-water, methane-pentane-water and methane-hexane water systems in four phases, one of which is the hydrate. The application of the phase rule to the methane-propane-water data proves that hydrates behave as solid solutions. The data of this paper and those in the literature were used to develop vapor-solid equilibrium constants,8 which permit prediction of conditions of hydrate formation from the analysis of a natural gas.

Jan 1, 1941

By R. J. Schilthuis, T. V. Moore

In a previous paper,' the results of some experimental work on the measurement of slippage in the flow of oil and gas mixtures through vertical pipes were presented. The data obtained were correlated and equations were deduced from which the performance of the experimental gas-lift could be predicted with reasonable accuracy. However, attempts to apply the equations to the calculation of pressure drops in actual flowing wells yielded erroneous results. At the time the results of the experimental work were published, no satisfactory explanation could be offered for the failure of the empirical equations to express properly the performance of wells. However, recent work has led to the development of a new hypothesis which presupposes certain conditions affecting the flow of oil and gas in wells. When the proposed equations are corrected to allow for these conditions, an agreement between the observed and calculated performance of the actual wells is obtained which in most cases is quite satisfactory, although it is subject to certain limitations. In this paper, the method of calculating the pressure drop in actual wells is considered, and the application of the method to the design of tubing is discussed. (For nomenclature used in this discussion, see Table 1.) Factors Affecting Slippage and Efficiency At the outset, a few of the principle factors affecting slippage and efficiency in the gas-lift discussed in the previous paper will be reviewed. In the flow of the mixture of oil and gas in a vertical pipe, slippage is the phenomenon of gas moving upward with a. linear velocity greater than that of the oil. Under steady conditions, if given quantities of oil and gas enter the tubing per unit of time, the same quantities of oil and gas per unit time must, on the average, pass every section of the tubing; otherwise, there would be accumulation or depletion of the oil or gas at some sections, and the flow would be unsteady. Therefore, if the gas is to flow at a greater linear velocity than that of the liquid,

Jan 1, 1933

By E. G. Gaylord

A BRIEF review of the oil conditions in California for a few years prior to 1923 is desirable for a clear comprehension of the development during that year and the results of the development. California's oil production during the five years preceding 1922 had been running from 100,000,000 to 115,000,000 bbl. annually. Crude oil stocks in storage had been declining steadily from 1915 to 1919, when there was a slight increase. They continued to decline through practically all of 1920, when they were drawn on to the extent of 11,350,000 bbl., leaving 20,930,000 bbl. on hand. In 1921, with production approximately 10,000,000 bbl. greater than the previous year, crude-oil stocks increased until, at the end of the year, there were 33,289,000 bbl. on hand. It would seem, therefore, that at the end of 1921 the so-called Pacific Coast province could absorb between 100,000,000 and 105,000,000 bbl. of oil per year, any in excess of this amount going into storage, not being, able to compete in other markets with oil outside the state. During 1922, daily production increased from 316,000 bbl. at the beginning of the year, to 500,000, at the end. This increase was the result entirely of production from the new fields, in the Los Angeles basin. In fact, considerable oil from the older fields of the state was shut-in beginning with March, 1922. As of 1922, the past development of the oil industry of California had been, in a general way, quite regular. As the need grew for more oil, pioneer drilling was increased, resulting in the discovery of new fields here and there. The good prices for crude oil that prevailed during the later part of the War and into 1921 had stimulated an extensive wildcatting campaign by California's larger oil corporations, as well as by smaller independent oil companies and by individuals. Many wildcat wells in California have required, two or three years for their completion, consequently the intensive wildcatting, which might be said to have started in California in 1917 and continued into 1922, found its greatest results with, the discovery of three very productive fields which, for all practical purposes, might as well have come in simultaneously.

Jan 3, 1924

The following list comprises the names of those persons who became members during the period May 10, 1919, to June 10, 1919. ALAYZA, CARLOS Box 850, Lima, Peru, S. A. BALLARD, P. A Surveyor, Midwest Refin. Co., Custer, So. Dakota. BARNEBL, A. J., JR.... Mech. Eng., The Dorr Co., 101 Park Ave., New York, N. Y. BILLINGS, GOODSELL Platteville, Wis. BRONSON, C. B., Mech. & Met. Engr., New York Central Lines, Room 1520, Grand Central Terminal, New York, N. Y. BUNCE, E. H Met., The New. Jersey Zinc Co., Palmerton, Pa. CHARLTON, D. E. A., Editorial Staff, Engrg. & Mm. Journals 10th Ave. & 36th St., New York, N. Y. DAVIS, JOHN N., Supt. of Mills, Engels Copper Min. Co., Engelmine, Plumas Co., Cal. DUKES, GLENN H., Chief Engr., The Sunday Creek Coal Co.,1001 Outlook Bldg., Columbus, Ohio. ERICKSON, ARTHUR .... Engr., United Smelt., Refin. & Min. Co., Mldvale, Utah. FLYNN, A. E Supt., Rand Consolidated Mines, Ltd., Goudreau, Ont., Canada. HIBBARD, WALTER R 63 Ashley St., Bridgeport, Conn. HOBSBAWN, I. BERKWOOD, Cons. Tech. Chem., Messrs. Gibbs. & Co., Valparaiso, Chile, S. A.

Jan 7, 1919

By George A. Laird

THIs old and once famous district played, through its enormous production of silver and gold, an important part in the history of the State of San Luis Potosi. According to a pamphlet prepared under the direction of the Governor of the State, Sr. Don Blas Escontria, and presented to the visiting members of the Institute during the Mexican meeting of 1901, this district is situated 20 km. east of the city of San Luis Potosi, in a range of mountains of moderate height, extending 135 km. N. and S., and 16 km. E. and W.; and the mineralized area hitherto developed is about 600,000 sq. m. The history of the district, as given by the record dated 1778, and formerly kept in the Sail Francisco convent, says that it was discovered in 1575 by Sr. Don Pedro Irarte, and adds that the city of San Luis Rey de Francisco de1 Potosi received its name (in allusion to the famous Potosi mines in Bolivia) by reason of the remarkable productiveness of its gold- and silver-mines in the first period of their exploration, during which they paid to the Crown, as quintos (the fifth part of the product), $97,000,000, as appears from the accounts of the royal treasury. The amount of the quintos paid during the " bonanza period " of 80 years was $72,000,000. The larger sum first mentioned probably represents a longer series of years. But either will suffice to indicate the great wealth of the mines. In 1663, the decadence of the industry began with the caving-in of several mines, concerning which the record of 1778, already cited, says, in substance, that on Good Friday one of the owners in the enterprise, in view of the unfavorable prospect of a lawsuit in which he was engaged, set fire to the timbers supporting the underground galleries and workings of the Sail

Jan 1, 1905

By C. B. Smith, A. G. Guy

The power and convenience of tensor analysis are employed in deriving the equations that describe three-dimensional diffusion in an n-component system plus vacancies. A "Kirkendall coordinate system, '' defined in principle by Kirkendall markers, is used in defining the intrinsic diffusion coefficients that are of primary interest. The defining equations are then transformed to local cartesian coordinates and to fixed cartesian coordinates, the latter being convenient for experimental measurements. Finally, it is shown how the intrinsic diffusion coefficients can be calculated from the experimentally determined quantities. It is generally recognized that any treatment of the essential diffusion phenomena in metallic systems—the jumping of atoms from one lattice position to another—must be based on movement of the atoms past Kirkendall interfaces.' A logical extension of this idea is the proposal that, fundamentally, diffusion must be described mathematically in terms of "Kirkendall coordinates." The basic equations thus obtained may then be transformed into other coordinate systems, when such transformation leads to simplification of either the experimental or mathematical treatment of diffusion data. Tensor analysis is clearly the appropriate mathematical tool for this purpose, since it provides methods both for determining general equations that are valid for all coordinate systems and for conveniently transforming the equations from one coordinate system to another system related to the first in some known fashion. For the present purpose three coordinate systems are used, and it is convenient to begin with a description of the relations among these three systems. FICK LAW FOR KIRKENDALL COORDINATES The reference coordinate system, and the one that is useful for most experimental measurements, is a cartesian coordinate system, xi (i = 1, 2, 3), fixed with respect to some point in the specimen, such as an end of the alloy bar undergoing diffusion. A second set of coordinates, the Kirkendall coordinate system, is one that in principle can be described by the location of inert markers (Kirkendall interfaces). A convenient mathematical relation between Kirkendall coordinates, x'i, and the reference cartesian coordinates, ii, is obtained by specifying that the Kirkendall coordinate system coincide with the cartesian system at time, t = 0. After diffusion has occurred for some time, t = t, the Kirkendall coordinate system will differ from the reference system in the manner shown schematically for the one-dimensional case in Fig. 1. The third coordinate system is Darken's1 local cartesian-coordinate system, xi, which is identical with ii in orientation and units, but which moves with the point under consideration in the Kirkendall coordinate system. Even though most diffusion problems are essentially one-dimensional, there is an advantage in first carrying out the analysis of the three-dimensional problem to gain a clearer insight into the assumptions that are made in the usual one-dimen-

Jan 1, 1962

By Walter Harvey Weed

INTRODUCTION. IN a previous paper upon the enrichment of mineral veins by later metallic sulphides,† the writer has shown that certain masses of rich ores, such as are found in many mines, either near the water-line or as bonanzas in depth, are of secondary origin, and are due to a leaching of lean ore and the concentration of the material by reaction between the solution and the unaltered ore below. The geological and mineralogical evidence is believed to form an adequate basis for a chemical and physical explanation of the phenomenon. In the present paper the writer will give a brief synopsis of this theory, and will apply it more particularly to deposits of the precious metals, laying special emphasis upon the dependence of such enrichments upon the presence of iron sulphide (as pyrite, etc.) in the primary ore, and upon structural features which control the circulation of the enriching solutions below the water-level. It is believed that many, though not all, of the bonanzas and pay-shoots of rich sulphide ores, especially those carrying gold and silver, which are encountered in ore-deposits, are of such secondary origin. Apparently it is essential that the occurrence and structural relations of such ore-masses should be understood, as the success of the mine is often dependent upon the finding and extraction of these ores. A legitimate deduction, too, is that such ore-deposits decrease in value with depth. As my own studies have been mainly in Montana, my illustrations must be drawn from the ore-deposits of this and adjacent States, with such as I have noted in hurried visits elsewhere. The literature of ore-deposits doubtless affords also

Jan 1, 1902

By O. S. True, C. H. Herty

It is well known that manganese will desulfurize molten iron through the formation of manganese sulfide, which, being only slightly soluble in the metal, rises to and enters the slag where it remains as such (mixer slag) or is converted partly or wholly to calcium sulfide (basic open-hearth slag). The reaction by which manganese sulfide is formed is Mn + FeS = MnS + Fe. This reaction is generally considered to be reversible, although McCancel states that such is not the case. The experimental work was carried out to confirm the results of Roh12 as to the reversibility of the reaction. Six trials are herein considered. In each 200 gm. of electrolytic iron free from manganese and sulfur were melted in a pure zirconia crucible in a carbon resistance electric furnace. To the melted iron in runs 2, 3 and 4 metallic manganese and manganese sulfide were added to give 1, 2 and 4 per cent. manganese respectively, with 0.50 per cent, of sulfur in each. In runs 5, 6 and 7, metallic manganese and iron sulfide to give the same proportions of. manganese and sulphur as in runs 2, 3 and 4, were added. The melts were held molten in the furnace for an hour and then cast into small ingots. The results of these melts are as follows: Ingredients of Charge Analysis or InRot ManOaneBe, SulfUR, ManOaneBe. SULFUR, Run Material Charged PeR Cent. PeR Cent. Per Cent. PeR Cent. 2 MnS + Mn............... 1.0 0.452 0.636 0.367 3 MnS + Mn............... 2.0 0.50 1.57 0.310 4 MnS + Mn............... 4.0 0.50 2.81 0.230 5 FeS + Mn................ 1.0 0.50 0.647 0.397 6 FeS + Mn................ 2.0 0.50 1.45 0.374 7 FeS + Mn................ 4.0 0.50 2.73 0.195

Jan 1, 1925

Discussion of the paper of J. E. Johnson, Jr., The Effect of High Carbon on the Quality of Charcoal-Iron, presented at the Cleveland meeting, October, 1912, and printed in Bulletin. No. 74, February, 1913, pp. 173 to °14, and of the paper of Albert Sauveur, Notes on Cast-Iron, presented at the New York meeting, February, 1013, and printed in Bulletin No. 75, March, 1913, pp. 503 to 524. CHAIRMAN. JOHN BIRKINBINE :-Just 20 years ago I had the pleasure, when I retired from the Presidency of the Institute, of introducing my successor, and this afternoon it is my pleasure to ask my good friend Dr. Howe to open this discussion. PROFESSOR HENRY M. HOWE, New York, N. Y. :-This paper of Mr. Sauveur's is extremely interesting. It is one of those papers that one wishes to read in the quiet of one's study, where it can be read with great profit. There are many points which he makes which I think are of very great value, in particular as to the importance of getting fine ;grained graphite by a relatively rapid cooling, combined with a high percentage of silicon. That theory would seem to be very promising; how far it has actually been carried out very likely Dr. Moldenke can. tell us.

Jan 5, 1913

By L. W. Kesler

Kansas produced 41,966,773 bbl. of oil in the year 1927, thereby taking fourth place among the oil-producing states of the Union. The daily average production decreased from 121,609 bbl. in January to 110,244 bbl. in December. Due to excessive flush production and the resulting decline in the price of crude during the year, operations, both in proved and outlying districts, were reduced materially from those of 1926. There were 2338 completions in 1926, but only a total of 1333 in 1927. Regardless of this decrease in the total number of completions, Kansas made a slight gain in total production for the year, producing 620,262 bbl. more than in 1926. This is accounted for, in part, by the comparative long life of the settled production from the Bartlesville sand areas to the east of the Nemaha granite ridge, and by prolific production in eastern Summer County from horizons new in their importance in the state, productive here at two localities along the axis of the granite ridge (Table 1 and Figs. 1, 2 and 3.) For convenience in further consideration, the state is divided into Eastern and "Western" Kansas. Special emphasis will be placed on those areas in the state of which but little is generally known, and which have not been given detailed consideration in previous publications.

Jan 1, 1928