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By Fred H. Kan

The production of petroleum in Venezuela during 1931 was approximately 118,767,000 bbl., a decrease of 18,904,000 bbl., or 13.7 per cent, compared with the previous year. This is the first break in production, which has risen steadily since 1920, and is attributable to restriction of output and drilling operations, in harmony with lessened demand, rather than to any real decline in potential production. Venezuela ranked third among the world's producers, having lost second place to Russia. The Bolivar coastal fields, which were extended approximately 14 miles southward during the year, continued to supply most of the oil. La Concepcion, Los Manueles and Quiriquire all showed marked increases. A new field of light oil was discovered on the north coast near Puerto Cumarebo, State of Falcon. Exports declined 15.7 per cent, from 137,377,000 bbl. in 1930 to about 115,800,000 bbl. in 1931. Crude oil in storage at the end of the year amounted to 7,450,000 bbl., a decrease of 2,150,000 as compared with 1930. Tankage utilized is about 40 per cent of the available space. A drastic decline in drilling activity reduced the number of wells completed in producing areas from 401 in 1930 to 116 in 1931. Only three wells were drilled in the Lagunillas field proper, but, the amount of closed-in production and proven acreage gave assurance of a satisfactory potential output. Of the 1580 wells drilled to the close of 1931 in the producing areas of the Bolivar Coast, 631 were active and 853 were closed in; 96 had been abandoned. The status of the active wells at the end of 1931 was as follows: flowing, 331; pumping, 99; gas-air lift, 201. Producing wells closed in numbered 452; workovers, 8; totally inactive, 393. Lago Petroleum Corp. and Venezuela Gulf Oil Co. placed in operation the first units of their electric power plants, the former at Punta Gorda and the latter at Las Morochas, and are replacing steam power in their operations as rapidly as possible. Compressor stations were also installed for use in connection with air-gas lift operations. A considerable volume of gas was treated in gasoline extraction plants, the tail gas being recom-pressed and utilized together with natural high-pressure gas, for stimulation of production.

Jan 1, 1932

By P. Duwez, L. Zwell

In recent years, the problem of pressing metal powder in a die has received much attention. The question has been the object of a Symposium held in New York in March 1947 under the sponsorship of the AIME; an excellent review of the subject may be found in Ref. 1. Various experimental techniques have been used to study the behavior of the powder in a die cavity. Two methods have been particularly successful; one consists of measuring the density distribution²,³ and the other makes use of a lead grid in the powder during pressing.4 In the present study, the pressure at various points on the bottom and the sides of a die 1.50 in. in diam was measured by means of small piston dynamometers and resistance sensitive strain gauges. In order to correlate the results with previous investigations, the pressure distribution inside the compact has also been determined by an indirect method based on density measurements. Strain Gauge Measurements of Pressure on Side and Bottom of Die A schematic drawing of the die used for measuring side pressures is shown in Fig 1. The pressure gauge consists of a 0.25-in. diam piston A which transmits the pressure to a dynamometer B, on which two Baldwin Southwark type 4-14 strain gauges are fastened 180" apart. Because the installation of several dynamometer assemblies along the side of the die would have been difficult, the pressure distribution was obtained in successive tests in which the distance from the gauge to the bottom of the compact was adjusted to different values by changing the length of the bottom piston. The dynamometer, disassembled from the die, was calibrated under compressive loads and showed a 1.00 ohm change of resistance for every 15,300 psi change of pressure (750 lb load change). All the strain gauge measurements were made with a null type Leeds and Northrup Wheatstone bridge. The sensitivity of the method was better than 1 pct and the accuracy was within 2 pct. These values were considered satisfactory in view of the rather large scatter in the measurements introduced by the random variation in packing the powder in the die. The stable ambient conditions and short time involved in the taking of observations made temperature compensation unnecessary-. The pressure distribution on the bot-

Jan 1, 1950

By H. Rush Spedden

Antoine M. Gaudin was a vigorously creative man and throughout his career an internationally respected leader of his chosen profession of mineral engineering. To his professional colleagues and clients and to his former students he was both "Professor Gaudin," their wise, inspiring, and enthusiastic teacher, and "Tony," their, warm and beloved personal friend. Thus, his teachings and his unique inquisitive-creative approach to problems live on and grow in the accomplishments of his students. Antoine Gaudin was born at the turn of the century in Smyrna, Turkey, where his father was general manager of a French-owned railroad. It was there that he spent his earliest years, literally in the shadow of classic marbles from diggings at the site of Aphrodesias, which his father had rediscovered. From this, Tony developed an appreciation of the arts. He eventually surrounded himself with art treasures; he reveled in the beauties of nature, and he cherished his choice collection of rhododendron and azaleas. His artistic traits led him to take up painting when his daughter, Elinor, sought his help in blending her tints for a water color. In typical fashion he was not satisfied until he had become adept with pastels in capturing the muted tones of distant landscapes and the technical properties of light and color. Unfortunately not many paintings were produced. His paternal grandfather was Marc-Antoine Gaudin, for many years secretary of the Academie des Sciences in Paris, and a well known chemist and mineralogist whose primary interests included the synthesis of precious stones. In an autobiographical sketch written in 1939, Dr. Gaudin recalled: "As a child I saw many of the original synthetic sapphires and rubies which my father had inherited. This, coupled with my father's avocation of mining ventures and archaeology, early decided that I would become connected with the mineral industry." One can speculate that the archeological activities of his father, the mineral systhesis experiments of his grandfather, and his own early studies of mineralogy and geology formed a base from which his special talents as an experimentalist were to develop. Laboratory research under Professor Gaudin's personal guidance was often an intensive, fast-moving, and exciting experience--especially to a new graduate student. First of all, Professor Gaudin was a highly skilled observer with seem-

Jan 1, 1976

By Ben E. Lusk

During the past five years, the surface mining industry in Appalachia has launched itself into a technological revolution, which has never been equaled during a similar period of time. Operators have begun to realize that effectively restoring land to a useful purpose, to the satisfaction of all concerned, has to start at the beginning of the operation and be an integrated part of it throughout. In order to insure continued mining in the mountainous areas, with protection of aesthetic beauty, things really have had to change. And so the new steep slope mining theory of "controlled placement" has been developed. Controlled placement is a broad term which means the placement of spoil in steep areas where its condition can be completely stabilized and revegetated. This includes the head of valley fill, mountain top removal, haulback, over the shoulder, block cut, and any other methods where the over-burden is technically delivered, hauled, or compacted, so that there is no adverse after effects when mining has been completed. [(Fig. 1)] Under controlled placement, our whole approach to mining has changed. Before any displacement of soil or uncovering of the coal seam transpires, a complete drainage system

Jan 1, 1977

By R. V. Wheeler, W. Francis

Of the methods that have been used for studying the chemical composition of coal, attack by reagents has not, in general, yielded much information. Most of the reagents used have been strong oxidants such as nitric acid or Schulze's solution. The use of a milder oxidizing agent, such as air at low temperatures, enables progressive changes in the character af the coal substance to be studied and thus helps toward an understanding of its constitution. British bituminous coals frequently have a banded structure. These bands (of four types) can be separated one from another and have been found to possess markedly different chemical characteristics, even when taken from contiguous portions of the same lump coal. It has been found convenient to give each of the ingredients of banded coal a distinctive name, more or less descriptive of its appearance, and the study of the chemistry of bituminous "coal" in England has resolved itself into a study of each ingredient separately. The coal chosen for this work was taken from the Top Hard seam at East Kirkby colliery, Nottinghamshire, a detailed chemical analysis of which has been recorded by Baranov and Francis.' The banded structure was well marked and the bands could readily be separated. The research was confined to the brilliant vitreous bands (vitrain), the dull hard bands (durain) and the "sooty partings" main); for previous work had shown that the fourth type, to which the name clarain has been given, is intermediate in character, chemically, between vitrain and durain. The method of experiment was, briefly, to draw a slow current of moist air through weighed samples (50 gm.) of the three ingredients, vitrain, durain, and fusain, in the form of powder (through a 60-mesh and on a 90-mesh sieve) contained in glass tubes which could be maintained at a constant temperature during prolonged periods. After passing through the coal, the air bubbled into a measured volume of

Jan 1, 1925

By AIME

WELL known as an outstanding practical metallurgist, the Chairman of the Institute of Metals Division also possesses a rare combination of research and administrative abilities. Louis W. Kempf was born in Muskegon, Mich., on March 22, 1898. Following his graduation from high school, he obtained considerable experience in the automobile industry while employed by Continental Motors, the Studebaker Corp., and Dodge Brothers. He enlisted in the U. S. Army Signal Corps in 1917, and served overseas with an aviation unit. In 1919, Mr. Kempf entered the University of Michigan and earned both B.S. and M.S. degrees. While there he was elected to Tau Beta Pi, Phi Lambda Upsilon, Alpha Chi Sigma, and Gamma Alpha. In 1924, the Aluminum Co. of America secured his services as a research metallurgist. With a steady job he married Elizabeth Skelley in Cleveland in 1926. They have one son now seventeen. After six years Mr. Kempf was made manager of the Cleveland research division of the Aluminum Research Laboratories which position he held until last year. In 1945 he was promoted to assistant director of the Laboratories. He will direct research involving process metallurgy in Cleveland and New Kensington.

Jan 1, 1946

By J. P. Dovel

HAVING been requested to prepare a paper referring especially to my patents as applied to blast furnaces, I shall confine my discussion to those improvements and inventions pertaining directly to the blast furnace itself, omitting a number of patents pertaining to blast furnace operations. I spent the early part of my life in the construction of blast furnaces, from rivet-heating to drafting and designing, much of the work relating to repairs and rebuilding. Later, as I became more interested in maintenance and operation of a group of blast furnaces, one fact especially made a lasting impression on me, namely that a very expensive piece of equipment was very short lived, and the expense of replacement, relining, etc., in many instances consumed most of the profits made while in actual operation. As far back as 1910, I began to lay plans to build with a view to permanency and not merely for a blast, the common expression at that time, which really meant only one or two years in southern practice. Since we did not then blow so hard most failures occurred in the bosh and hearth. The failure of either generally meant a complete new lining, as the inwall did not look good enough to last another blast. At that time we were using two types of hearth, one of heavy steel plate protected by well and sprays on the outside, and .one of heavy. cast iron, made in sections and bound together with wrought-iron bands. The former type proved dangerous, for if the iron should come through, as it frequently did, it would cut away the steel plate, quickly turning large quantities of molten iron into the water, causing a severe explosion and costly repairs. The cast-iron type gave trouble also by the iron finding its way through the joints between the sections, which was' not so serious; since the iron would not cut away the heavy cast-iron sections very quickly, and generally caused only small damage, and repairs-were easily made. Both types have been improved; the former by the introduction of cast-iron -water-cooled plates, placed on the, inside of the steel, jacket. This has proved to be very good construction, but has no real claim to permanency: As the cast-iron plates cannot be replaced from the outside, therefore the operator must assume that some time, at no late date, he must replace them from the inside, which will mean a blowing out of the furnace. The heavy cast-iron hearth has been improved by making the

Jan 1, 1928

By Franklin R. Carpenter, W. P. Headden

TWO notes have already appeared in the Transactions concerning the columbite or tantalite of the Black Hills tin-mines. In vol. xiii., page 232, Prof. Schaeffer speaks of the mineral as tantalite, and concludes by saying that its separation from the tinstone "is a matter which will, I believe, prove puzzling to the wisest metallurgist." He also observes that he is unable to find by analysis in his specimens the least trace of columbic acid. Prof. W. P. Blake, in the same volume, at page 696, says: " Even if it [tantalite or columbite] were present to a considerable amount, it would not injure the tin in smelting. It does not alloy with tin, but carries a small percentage of tin, which would probably be liberated in smelting." He calls the mineral columbite from the fact that a great number of specificgravity tests invariably indicated that it should be so classed. We have made chemical tests as well as specific-gravity tests upon many samples from many different parts of the Hills. Our analyses have always shown the presence of columbic acid, and the specificgravity tests have always indicated columbite, as we have elsewhere shown.* As Prof. Blake has already observed, it is not found in such close association with the tin as to prevent separation by a rough handsorting, but it is usually present with the stream-tin. As Prof. Schaeffer says, it cannot be separated by ordinary concentration; and while, as declared by Prof. Blake, its columbic acid may not unite with the tin in any form, yet its iron and manganese oxides may be reduced, and thus lower the quality of the tin produced, as is also the case when the smelting charge contains wolfram. To determine the effect of columbite in the ordinary potassium cyanide assay, there were assayed at the Dakota School of Mines four samples containing different proportions of columbite. The results, published in the report of the school for 1888, seemed to indi-

Jan 1, 1889

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Jan 1, 1938

By B. B. Rath, Hsun Hu, R. S. Cline

FOLLOWING the techniques used by Beck and co-worker~ "~ the characteristics of selective growth in the recrystallization of a zone-refined aluminum single crystal, rolled 80 pct at -78°C in the (110)[112] orientation, have been studied. The material was 99.999+ pct pure. The as-grown crystal had a resistance ratio, R(298°K) /R(4,2°K), of approximately 5000. The method of preparation of the single crystals and the necessary precautions in handling them during rolling in order to avoid recrystallization in locally distorted regions were described in an earlier paper.3 The rolling texture of this zone-refined aluminum crystal is practically identical with that of less pure aluminum crystals rolle! in the same orientation, i.e., a very sharp (110)[112]. Random nuclei were provided by artificial nuclea-tion by abrading one face of the rolled crystal on 600-grit emery paper in a random fashion. The thin layer of disturbed metal recrystallized at room temperature into fine grains almost immediately. An X-ray diffraction pattern was taken from the abraded surface of the crystal, and the relative intensities of the various reflection peaks were compared with those obtained from a powder specimen. As shown in Fig. 1, the relative intensities of the various peaks from the recrystallized layer varied somewhat from experiment to experiment, depending presumably on the abrading technique. However, the texture of the recrystallized layer produced by this method is nearly as random as that of a powder specimen. Fig. 2 shows the texture determined from the "growth side" (face opposite the abraded surface) of the crystal after it was kept at room temperature for 100 hr. The specimen was only partially recrystallized, as shown by the remaining deformation texture. The new orientations are derived from the recrystallized grains grown through the thickness of the crystal from the "nucleation side" (the abraded surface). Fig. 3 shows the texture after complete recrystallization produced by annealing at 60°C for 1 hr. The arrows indicate 40-deg rotation around the (111) axes of the deformation texture. The microstructure of a completely recrystallized specimen is shown in Fig. 4. As shown in Figs. 2 and 3, the texture of the re-crystallized grains grown from the nucleation side to the growth side is essentially the same as that observed in less pure aluminum' (99.994 pct) and dilute alloyz crystals rolled in the same orientation. How-

Jan 1, 1968

By Alden B. Greninger

In a recent study1 of the deformation of metastable beta copper-zinc and beta copper-tin crystals, it was established that the parallel markings that appear on the surface of these crystals after slight deformation represent lattice transformations. Stereographic analysis showed that in beta copper-tin, the poles of these markings deviated one or two degrees from poles of the form {133}. In beta copper-zinc the plane delineated by the markings corresponded to no one crystallographic plane of the matrix lattice; the marking poles deviated from 5° to 11° from poles of the form (110), and were displaced only a few degrees from (110) zones. Inasmuch as the new transition lattices produced as the result of the deformation are different for each alloy, it was thought at first that the habits of the markings might be the result of a cooperation between matrix lattice and transformed lattice. (Both matrix lattices arc body-centered cubic.) Such a cooperative effect is thought to obtain in the formation of Widmanstätten figures, for it is well known that the matrix lattice alone does not determine the habit assumed by a segregate phase. On the other hand, it is not inconceivable that the dissimilarity in marking habit might be due to differences in deformation characteristics of beta brass and beta bronze. Barrett and co-workers2 have shown that slip-line habits in pure iron are markedly different from those in high-silicon ferrite; and although it has been repeatedly demonstrated that plates of a segregate phase do not necessarily form on the slip planes of the matrix lattice, deformation characteristics may be more intimately allied with plate formation when a transformation is made to occur as a result of plastic deformation. However, there is the fact that the orientation of markings in metastable beta copper-zinc is the same whether the markings be produced by quenching, deformation, or liquid-air cooling; likewise, quenching and deformation markings in metastable beta copper-tin are oriented in the same way with respect to the beta matrix. During the course of the investigation referred to above, samples of 52:48 (stable beta) copper-zinc were deformed and examined micro-

Jan 1, 1938

By Alden B. Greninger

In a recent study1 of the deformation of metastable beta copper-zinc and beta copper-tin crystals, it was established that the parallel markings that appear on the surface of these crystals after slight deformation represent lattice transformations. Stereographic analysis showed that in beta copper-tin, the poles of these markings deviated one or two degrees from poles of the form {133}. In beta copper-zinc the plane delineated by the markings corresponded to no one crystallographic plane of the matrix lattice; the marking poles deviated from 5° to 11° from poles of the form (110), and were displaced only a few degrees from (110) zones. Inasmuch as the new transition lattices produced as the result of the deformation are different for each alloy, it was thought at first that the habits of the markings might be the result of a cooperation between matrix lattice and transformed lattice. (Both matrix lattices arc body-centered cubic.) Such a cooperative effect is thought to obtain in the formation of Widmanstätten figures, for it is well known that the matrix lattice alone does not determine the habit assumed by a segregate phase. On the other hand, it is not inconceivable that the dissimilarity in marking habit might be due to differences in deformation characteristics of beta brass and beta bronze. Barrett and co-workers2 have shown that slip-line habits in pure iron are markedly different from those in high-silicon ferrite; and although it has been repeatedly demonstrated that plates of a segregate phase do not necessarily form on the slip planes of the matrix lattice, deformation characteristics may be more intimately allied with plate formation when a transformation is made to occur as a result of plastic deformation. However, there is the fact that the orientation of markings in metastable beta copper-zinc is the same whether the markings be produced by quenching, deformation, or liquid-air cooling; likewise, quenching and deformation markings in metastable beta copper-tin are oriented in the same way with respect to the beta matrix. During the course of the investigation referred to above, samples of 52:48 (stable beta) copper-zinc were deformed and examined micro-

Jan 1, 1938

By Stanley C. Herold

At the present time five localities in the Argentine Republic are known to bear direct evidences of the presence of petroleum. The segregation of these localities is more or less arbitrary inasmuch as minor indications may be found to extend from one locality to the other at no regular distance apart, especially in the northern and western part of the republic. These localities are listed as follows: North Argentine-Bolivian region, Salta-Jujuy district, provinces of Mendoza and Neuquen, Comodoro Rivadavia, and the Gallegos-Punta Arenas region. Economic conditions attract us to the possibilities of developing these and other regions of countries in the southern hemisphere. Development work will, naturally, be undertaken first in such localities as present direct manifestations of the presence of petroleum; "hidden fields" may exist, but, unless discovered by accident, their development will be left to the last. The problems to be solved in the development of the petroleum resources of the Argentine republic are mainly of stratigraphy, structure, and transportation. We are not here concerned with the unfavorable climate of the countries to the north in the tropics where, for us of the "far north," life hangs by a thread ready to be severed by a mosquito, gnat, or tropical germ. North Argentine-Bolivian Region The North Argentine-Bolivian region has already been described by the author.' Geographically and geologically this is admittedly one field extending from Argentine into Bolivia. It is not necessary to repeat here the various conditions pertaining to this field, though the summary may be quoted as follows: Extending from northern Argentine northward into central Bolivia is a belt of petroleum seepages. On account of the remoteness of the district it has, heretofore, been little considered by oil operators. The regional geology is comparatively well understood but the local features have not been carefully detailed. Development work in the past has been done on an unscientific basis and has led to failures. At the present time, access to the region is somewhat difficult but, no

Jan 1, 1921

By Enrique Touceda

As in the case of steel and the non-ferrous alloys in general, the use of the microscope in connection with the manufacture of malleable cast iron has proved of inestimable value to the industry. Had its use not been invoked, many facts either would not be known at all or, if suspected, would be confined to the realms of conjecture. No fairer statement could be made than that the start of real progress in the industry was coincident with the application of metallography to the product, though the full significance of this statement can hardly be appreciated except by those who not only are conversant with conditions as they existed at the time referred to, but are familiar with the character of works' practice at the present time.. A few years ago, about the only test made to ascertain the physical properties of the product, except in the case of certain plants, was the bending of a casting to destruction, not only with the object of discovering whether or not the metal was ductile, but for the purpose of inspecting the fracture. The characteristics of the fracture, if correctly interpreted, were known to be of value in locating the trouble in castings that were inferior. In general, it was found that if a casting of medium or heavy section would bend through a wide angle before failure took place, the fracture in the majority of cases would have a black velvety appearance; while if it was held at different angles to the direction of the rays of light, it would show a change of color and an iridescent sheen. But an inferior air-furnace heat or anneal might yield castings which, if thin and consequently largely decarburized, could be bent double on themselves and still not possess the fracture described. If, on the other hand, a casting broke short, its fracture might have one of a great many different color and structural peculiarities. Depending on the cause of the trouble, such castings might have any of the fracture characteristics, of which the following is but a partial list.

Jan 1, 1922

By Enrique Touceda

As in the case of steel and the non-ferrous alloys in general, the use of the microscope in connection with the manufacture of malleable cast iron has proved of inestimable value to the industry. Had its use not been invoked, many facts either would not be known at all or, if suspected, would be confined to the realms of conjecture. No fairer statement could be made than that the start of real progress in the industry was coincident with the application of metallography to the product, though the full significance of this statement can hardly be appreciated except by those who not only are conversant with conditions as they existed at the time referred to, but are familiar with the character of works' practice at the present time.. A few years ago, about the only test made to ascertain the physical properties of the product, except in the case of certain plants, was the bending of a casting to destruction, not only with the object of discovering whether or not the metal was ductile, but for the purpose of inspecting the fracture. The characteristics of the fracture, if correctly interpreted, were known to be of value in locating the trouble in castings that were inferior. In general, it was found that if a casting of medium or heavy section would bend through a wide angle before failure took place, the fracture in the majority of cases would have a black velvety appearance; while if it was held at different angles to the direction of the rays of light, it would show a change of color and an iridescent sheen. But an inferior air-furnace heat or anneal might yield castings which, if thin and consequently largely decarburized, could be bent double on themselves and still not possess the fracture described. If, on the other hand, a casting broke short, its fracture might have one of a great many different color and structural peculiarities. Depending on the cause of the trouble, such castings might have any of the fracture characteristics, of which the following is but a partial list.

Jan 1, 1922

By Chase Palmer, Edson S. Bastin

While the reducing action of organic matter, of ferrous sulphate, and of hydrogen sulphide has frequently been invoked to account for the deposition of native gold and silver from ore-forming solutions, the high efficiency in this respect of certain of the metallic minerals which form the ore itself has not been suffciently recognized. If a little finely powdered chalcocite is placed in a test-tube arid 2 or 3 cc. of a dilute solution of gold chloride are poured over it, two or three shakes of the tube suffice to remove all the gold from the solution. The color of the solution changes from yellow to pale green, showing that copper is dissolved simultaneously with the precipitation of metallic gold. If a piece of chalcocite is hung in a dilute aqueous solution of silver sulphate (1/40 normal), a coating of silver begins immediately to form on the mineral, and within a few moments a beautiful silver tree has developed, similar to that formed when metallic zinc is immersed in a similar solution. When similar experiments are conducted with other sulphides and with certain arsenides and sulph-arsenides, especially those known to be commonly associated with native silver in ore deposits, it is found that these minerals differ greatly in their efficiency as precipitants, especially in their effect on silver solutions. The tests made with most of the minerals were qualitatipe only, but the reactions of a silver sulphate solution on chalcocite and niccolite were submitted to quantitative study to determine the nature of the reactions involved. Quantitative studies of the reactions with other minerals are now in progress

Jan 1, 1914

The Committee, appointed early in May, met and organized in Washington, May 9, 1923, and were then advised that such data as they required would as far as obtainable be submitted to them in tabulations, and that they could not be allowed to see the individual reports nor know the identity of the operators on whose reports the figures submitted were based, therefore the Committee's valuation is based on data received from your statisticians, and on tonnages estimated by your staff and by the United States Geological Survey. Various methods of valuation for mining properties have been suggested, but all authorities seem to agree in accepting, as the fairest and most practicable and logical, a capitalization of the estimated future earnings, when such estimate can reasonably be made. Hoover and Finlay both emphasize this. The United States Supreme Court says in Cleveland, Cincinnati, Chicago & St. Louis Railway Co., v. Backus, 154 U. S. 439: But the value of the property results from the use to which it is put and varies with the profitableness of that use, present and prospective, actual and anticipated. There is no pecuniary value outside of that which results from such use. The amount and profitable character of such use determines the value. The Committee on Federal Taxation of the American Institute of Mining and Metallurgical Engineers, appointed in 1919, in its report states: A proper value of a mining property is the present value of the prospective net earnings, taking into account probable variations in output and value. Ingalls ("Wealth and Income of the American People," p. 97) says: The fundamental principle of mine valuation is the present worth of an annual dividend accruing during the period of years corresponding with the lie of the mine. It is a convention that the estimated period shall not be more than 30 years.

Jan 1, 1924

George Smith, Sydney, N. S. Wales (communication to the Secretary): The very interesting paper by Mr. Emmons on " The Secondary Enrichment of Ore-Deposits " has just come under my notice; and its reference to my own paper* on " The OreDeposits of the Australian Broken Hill Consols Mine "† is therefore only noted some two and a half years after its publi-

Jan 1, 1903

Book Review Mexico, TODAY AND Tomorrow. By E. D. Trowbridge, Detroit. The McMillan Co., New York, 1919, 353 pp., 7;2 X 5 in. $2.00. The first eight chapters are devoted to an historical narrative of the Mexican peoples from the earliest times to the close of the war with the United States in 1345. "In dealing with events antedating what may be termed modern Mexico" the author has "made no attempt at original research, and so far as concerns anything prior to 1900, the work here presented is a repetition, a reflection, of the findings of opinions of Fiske, Prescott, Bancroft, Luis Perez Verdia and other authorities." The remainder of the hook deals with Mexico during and since the Diaz regime. It is interesting throughout but is not always convincing or consistent. Social conditions are described in a way illuminating and possible only to one who is familiar with the peon and his hitherto seemingly hopeless position in reference to the wage system and church oppression. In fact, the author makes the hold accusation that the "primitive rather than immoral" condition of the peons in the matter of their marital relations is due to the disregard of the church for their welfare and capabilities. The true accounts of the Madero revolution and the Huerta regime read like fascinating medieval fiction. The reason given for men remaining in the Madero army is still the controlling one regarding any of the armies there. "They had horses, arms, all the food they wanted, money to spend and no work." The discussion of Mexican financial schemes is wholly from the Carranza viewpoint. To meet a monthly deficit of ten million pesos the author says "the government forced loans from the National Bank, and Bank of London and Mexico, and repeated the operation several times, finally practically exhausting their bullion and cash reserves. Hostile foreigners refer to this operation as the looting of the hanks! Drastic as this action was, there was good ground on which to justify it." However, that necessity knows no law is never an acceptable tenet except to him who applies the screws. The discussion of the economic problems and their solution is rather chimerical and presupposes a civil and national virtue in the present government not discernible except to one ultra friendly. The book is an interesting exposition of the very much involved situation from the viewpoint of approval of both the Carranza government and the attitude of the United States in its dealings with him. The editing of the book leaves something to he desired. P. E. B.

Jan 9, 1919

By H. H. Vogel

THIS paper describes the milling practice and operating results of the recently installed heavy-media separation plant of Barton Mines Corporation, the world's largest producer of garnet. This pioneer application of heavy-media separation (sink-float) processes for the beneficiation of a nonmetallic ore is unique in many respects, the details of which will be apparent from the following presentation. CHARACTERISTICS OF THE ORE The property is on Gore Mountain, 5 miles west of the village of North Creek, New York, and 11 miles by road. The altitude of the mine is approximately 2800 feet. The valuable mineral, garnet, occurs in a surface deposit, the ore body being about ¾ mile long and varying in width from 50 to 300 ft. The garnet, principally almandite, Fe3A12 (Si04)3, occurs in a metamorphic rock of uncertain origin. The gangue mineral is principally hornblende, which constitutes from 40 to 80 per cent of the rock. The remainder of the gangue is divided between plagioclase feldspars and hypersthene, with smaller amounts of biotite, apatite and pyrite. The garnet content of the ore body varies from 5 to 20 per cent of the mass and averages about 10 to 12 per cent. The garnet occurs as crystals, mostly imperfectly developed, known locally as "pockets." These crystals vary in size from a fraction of an inch to a foot or more in diameter. Occasionally crystals have been found up to 30 and 36 in. in diameter but they average 4 to 6 inches. Nearly every crystal of garnet is surrounded by a rim of coarsely crystalline hornblende. The quarry faces are striking in appearance, showing crimson-red garnet crystals with their coal black rims scattered over a grayish black background. The specific gravity of the garnet is 3.8 to 4.1 while that of the hornblende ordinarily is 3.07 to 3.24. Some specimens of very dense hornblende have been found with a specific gravity as high as 3.40. The garnet crystals are laminated in structure, and readily cleave into flat, tabular pieces with sharp, chisel-like edges. Even when crushed to a very fine size, the garnet retains this flat, sharp, slivery grain shape. This characteristic, together with its hardness and toughness, gives it its value as an abrasive. FORMER OPERATIONS Mining operations have been carried on for 60 years. Until 1023, only the oxidized (soft rock) section of the ore body was mined. The oxidation, which affected the garnet only slightly, made possible the removal of the garnet from the rock by hand after it was blasted down, using small hand picks. In 1923 a mill was erected on the property, and was rebuilt and redesigned in 1928. Before the adoption of heavy-media separation, concentration was effected by

Jan 1, 1943