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By Francis P. Sinn

IN the zinc smelting industry the year 1947 seems to have been one of putting one's house in order rather than one of any material technical development or radical change in operating conditions. Labor generally has been in better supply but several plants report a scarcity of skilled workmen. Some plants continue to operate on the basis of a six-day week and will probably continue to do so until labor is more plentiful. Only one plant is known to have operated on a curtailed basis because of labor shortage, but here the difficulty was lack of proper housing facilities. Necessary materials and equipment for much-needed maintenance and modernization have been in short supply so these programs have often been delayed. Laborsaving devices of the "Payloader" type have been more generally used for handling materials. Slab zinc production was discontinued during the last months of the year at Danville, 111. and at Langeloth, Pa. Both of these plants used the Hegeler type of furnaces fired with producer gas. It is understood that the rolling mill and possibly the acid plant at Danville will continue to operate. At Langeloth acid will be produced from

Jan 1, 1948

September 20, 1917. As this meeting terminates the year's agreement under which the Engineering Foundation has appropriated its income to the National Research Council, a brief summary of what has been accomplished seems called for. The Research Council was organized Sept. 19, 1916. The Executive Committee was appointed at that meeting; since that date two other meetings of the Council have been held, one in Boston, on Nov. 13 and 14, the other in Washington on April 19. During the intervals between the meetings of the Research Council, the Executive Committee has conducted all of the business of the Council. There have been 29 meetings of the Executive Committee, 13 in New York up to the first of May, 15 in Washington subsequently, and one in Boston. The meetings in New York were devoted to the organization of the Research Council and especially to appointment of committees. At the outset, the Council had no very clear idea of the way in which it was to organize; there were several other groups of scientific men at work, among them, the Research Committee of the American Association for the Advancement of Science and the Engineering Committee of the Advisory Commission to the Council of National Defense. Time was spent in straightening out these two principal complications, both of which were satisfactorily adjusted. The upshot of these negotiations is to leave the Research Council as the only representative, national body of research men, assisting the Government. During the period up to May, the Executive Committee in New York selected carefully the personnel of some 25 principal committees, and of a large number of sub-committees; so carefully were these chosen that of the entire number, several hundred, there have been only one or two declinations. Some of the important steps in the development of the Research Council are the establishment of the Military Section, composed. of the members of the Council connected with the Government and resident in Washington. This Section put the Research Council into close contact with the most important officials of the Army and Navy. From it has grown the Washington office of the Council, and the recognition of the Research Council as the "Department of Science and Research of the Council of National Defense; " and the establishment of the Washington office after the Council of National Defense had officially recognized the Research Council. About this time Dr. Hale, Chairman of the Council, appointed Dr. Millikan to be Vice-Chairman to represent the Council in Washington, and Dr. Millikan has since then been in charge of the work of the Council. At the request of the Secretary, Dr. Millikan has prepared a brief report of some of the work of the Research Council during its first year, which is appended to this report. It shows that the Research Council has been active in much of the important work. under way in our preparations for war, and that it has rendered effective services to the Government.

Jan 12, 1917

By James Douglas

American metallurgical inventions have not always been absolute metallurgical improvements, if accurate work be the standard of comparison; but when we review the new methods and machinery which have been generally accepted, we find that some have become essential to the metallurgist the world over, while all are so admirably adapted to the peculiar requirements of our local conditions that they have entirely supplanted foreign processes and appliances. The necessity of diminishing to the utmost the employment of labor (owing to its great cost), and the inexorable requirements of our modern joint-stock corporate system, which demands that large quantities be worked up in order to secure large returns, regardless betimes of waste, have been the impelling motives to invention, and indicate the special directions in which originality has been exercised. As might be anticipated, the West has been the most fertile field of inventions by miners and metallurgists, by reason of its great and varied mineral wealth, locked up in ores sometimes lean and often of intricate composition, which must be profitably handled, at a great distance from fuel and from building-materials, by workmen who are paid wages very much higher than those received by their fellow-workmen of like craft in Europe, and in some localities twice as high as those paid for like services even in the eastern States. Moreover, paradoxical as it may seem, the technical inexperience of many of those engaged in mining and metallurgy has helped rather than hindered the progress of invention; fop while there may have been ignorance, there has been radical freedom from

Jan 1, 1894

By E. C. Bain

THE more familiar compositions of iron-carbon-chromium1 and the iron-carbon-tungsten2 systems have been investigated with a degree of thoroughness which has permitted the construction of their three-dimensional equilibrium diagrams; and it is probable that these equilibrium diagrams are sufficiently accurate for the present metallographic needs. Strangely enough, in spite of their importance, the alloys of iron, carbon and manganese apparently have not been investigated in the same systematic manner, and so far as is known, no three-component equilibrium diagram for this system is available. Even iron-carbon-nickel alloys3 have been studied rather more thoroughly; for these the solidus and liquidus surfaces have already been determined, but the solid transformations in this, as in the manganese system, have not been reported systematically. The present paper deals with the constitution at equilibrium of a series of 36 iron-carbon-manganese alloys of commercial purity limited by 1.5 per cent carbon and 15 per cent manganese, a range of compositions including most of the manganese steels. The temperature range of melting has not been determined, nor has the high-temperature (delta iron) ferrite equilibrium been included in the study, it being considered that the more important characteristics of the manganese steels are their ordinary transformations in the solid state. The delta iron region is almost certain to be a small tetrahedron not very different in magnitude or contour from that in the iron-carbon-nickel diagram. It is probably true

Jan 1, 1932

The annual spring excursion of the College of Mines, University of Washington, is being made to the Coeur d?Alene region of northern Idaho. A party of 15 students and, instructors is visiting the Bunker Hill and Sullivan mine, mill and smelter at Kellogg, and several mines and mills in the neighborhood of Wallace and Mullan.

Jan 5, 1917

By S. F. Emmons

Br far the greater number of the members of this Institute are men who are engaged in the strenuous work of the technical part of their profession, and find little time for the abstract scientific work which is less distinctly practical and pecuniarily emunerative. There is, however, a small but increasingly numerous class whose members devote themselves to broad geological problems which underlie the systematic development, and whose work, theoretically, ought to precede and form a basis of that of their more practical brethren. These are the so-called mining or economic geologists, who are, for the most part, connected with State or National geological surveys. From the character of their work, the life of these men necessarily follows rather different line's than that of most of their colleagues, and is not generally familiar to them. It seems admissible, therefore, that to the life of a prominent member of this class, who died during the past year, having literally sacrified his life to his work, a more extended notice should be given than the relatively small number of his contributions to the Transactions might seem to justify. George Romans Eldridge, son of Ellery and Sarah (Mathews) Eldridge, was born on Cape Cod at Yarmouth, Mass., Christmas day, 1854. His boyhood education in the public school at Yarmouth was followed by a six years' course in the Public Latin School at Boston, from which lie entered Harvard Uni¬versity in 1872, being graduated with the highest rank in his class in the natural sciences in 1876. During his college course he spent the summers of 1875-6 at Cumberland Gap, Ky., as volunteer aid to Prof. N. S. Shaler, who was then in charge of the State Geological Survey of Ken¬tucky. This vacation work, undertaken by him rather as a pastime, gave him his first leaning toward geology. Soon

Mar 1, 1906

By Henry N. Doyle

Basic procedures in the mining industry have changed only slightly over the centuries since metals and fossil fuels became an essential part of man's economic and cultural life. Mining techniques of the 20th century bear a close resemblance to those of the ancients: exploration, ore breakage and removal, hoisting, and processing. The great advances, however, have been in equipment and machinery of greater size and speed which allow greater efficiency in each of these operations, with a corresponding reduction in manpower requirements. Yesteryear production was measured in pounds per man-day; today a giant and complex, but highly efficient, continuous mining machine can remove as much as eight tons of material a minute from the coal face. If our energy and metal demands of the future are to be met, and at this time it can be assumed that coal will continue to supply a significant part of the energy demand, other dramatic and spectacular technologic advances must be accomplished. Along with mechanization, however, public policy will require the industry to place greater emphasis on health and safety protection, as has been well demonstrated by recent actions of Congress. Together, fossil fuels and metals formed the basis for the industrial revolution-coal to develop power and metals to transform power into useful energy. Strangely enough, however, the mining industry the world over has lagged behind the continuous social changes brought on by the industrial revolution, such as preventive health and industrial hygiene services, and other programs directed to the well-being of the worker. In some countries this resistance, to change may have led in part to the nationalization of the coal industry. Whether this disinclination to social change in the industry of the United States reflects managerial attitudes, inept labor leadership, government neglect, or economic relationship would be the subject of an interesting study. Doubtless the mores of miners and their resistance to change, as well as their geographic isolation from other industrial groups, may have had a strong influence on these factors. In every major coal mining country the accident rate in the coal industry is substantially higher than other industrial groups, and the cost of pneumoconiosis compensation in some countries is greater than the combined costs for all other occupational diseases from all other industries. The high social cost of occupational accidents and diseases may have been a factor in the closing of the industry in at least two countries. Despite diminishing manpower needs, the industry is faced with critical manpower shortages. Miners once reared their sons to be miners; now it appears that the opposite is true. This factor alone, however, does not explain an acute labor shortage in the industry. Traditionally, the industry drew much of

Jan 1, 1976

By M. J. Duggin

Evidence is produced below to show that the carbide "Mn,C," reported by Kw,and ersson' is really a mixture of two carbides. One is an Fe-Mn carbide which is probably isomorphous with hexagonal Mn15C4, reported by Bouchand and Pruchart.' The othev is a tetragonul Fe-Mn carbide with cell dzmensions close to those reported previously by the author3 for an Fe0.1Mno. carbide. IN a recent investigation several Fe-Mn carbide specimens, each weighing about 5 g, were prepared in a manner previously reported.3 Debye-Scherrer X-ray photographs were taken of at least two samples from different parts of each specimen using a 114.6-mm-diam camera. The exposure time was 2 hr using filtered chromium radiation, a tube voltage of 35 kv and a tube current of 10 ma. In the case of one specimen, which contained nominal weight percentages of iron, manganese, and carbon of 9.40, 84. 6,, and 6.0, respectively, duplicate chemical analyses indicated f1.2 and 5.5 wt pct C to be present in the two samples taken of the specimen: no graphitic carbon was detected. One powder-diffraction pattern of this specimen indicated the presence of the tetragons: carbide reported earlier,3 (a = 6.772A, c = 9.427A), plus cementite (O), plus an unknown structure. The second powder-

Jan 1, 1970

By W. E. C. Eustis

1st. The fine iron ore is mixed with a sufficient proportion of fine coking coal, and is coked in any of the ordinary methods for making coke. The effect of this is to convert the iron oxide into sponge in such a shape that the usual trouble of oxidation is avoided. 2d. The resulting mixture of coke and sponge is melted down ill an ordinary cupola, the coke furnishing more than sufficient fuel for that purpose. I may briefly point out here that in the first place the iron is sponged, and this sponge, as is well known, contains no phosphoras or silicon when the reduction takes place at a low temperature; and in the second place this sponge is melted down in a cupola in which there is no zone of reduction for phosphorus or silicon, and that con . sequently the resulting iron should be free from both of these impurities. 3d. The liquid sponge, now carburized, is run into an open-hearth furnace, where the requisite degree of hardness or softness is obtained by adding some of the fine ore, and the usual dose of ferromanganese, I have merely given above the rough outlines of the prows, bat it is my intention, as early as possible, to bring the process more fully before the Institute.

Jan 1, 1881

By Carlo Massa

THE Societá Auonima di Miniere e di Alti Fourni, familiarly known as the " Elba Company," works the rich ore-deposits of the Island of Elba under a long-term contract with the Italian Government. The ore-deposits are scattered over the eastern and southeastern coast; but as those parts of the island are not well provided with ports, the blast-furnaces were built at Portoferraio, the principal town of the island, situated on the northern shore, and possessing a magnificent natural harbor where even vessels as large as the battleships of the Italian navy can comfortably anchor. In the selection of Portoferraio. the cost of transporting the iron-ore from the different mines to the blast-furnaces has been reduced to a minimum, and shelter has been provided for the Company's flotilla of tugs and barges, as well as for the steamers carrying coal and pig-iron. The whole plant, of which a general view is given in Fig. 1, comprises 1. A discharging-pier with unloading-cranes. The ore and coal are transported from this pier by means of an aerial cable-rail¬way to the coal- and ore-storage yards. This cable-railway is supported by an iron bridge extending from the pier to the shore and by a wooden trestle extending from the shore to the yards. , 2. Blast furnaces, two in number, with all the accessory appa¬ratus, such as blowing-engines, dry purifiers, Cowper hot-blast stoves, hoists, etc. 3. Coke-ovens, two batteries, with coal-bin, crushers and boilers. 4. Engine-house containing the blast-engines and the electric generating-station. 5. Pumping-plant. 6. Narrow-gauge railways.

Mar 1, 1905

By K. Sallmann

Spurred by a variety of factors, coal flotation is making headway among the preparation plants of West Germany. The author gives some statistics on German coal flotation plants and information on the properties of the feed and quality of the derived products. Types of machines and reagents used, dewatering practices, tailings disposal, and thickening operations are covered. There is special emphasis on the many-sided problems that confront German coal preparation engineers. The coal mining industry of West Germany is concentrated in three coalfields: the first on the Ruhr and the Rhein rivers, the second on the Saar river, and the third near the frontier between Germany and the Netherlands, around the towns of Aachen and Erkelenz. The total run-of-mine production of these three coalfields amounts to 736,000 tpd which come from 145 collieries. There are 121 washeries, 43 of them with a flotation plant. The total throughput of these 43 washeries is 280,000 tpd, out of which 26,000 tons (9.3 pet of the washery feed coal) are cleaned by flotation. The capacity of the individual flotation plants varies within relatively wide limits, the average being 40 tph and the capacity of the largest flotation plant being 120 tph. During the last few years, the number and size of flotation plants have been steadily increasing, although flotation must be looked upon as an expensive and rather complex cleaning process. The considerations which have led to the widespread application of flotation may be summarized as follows: 1) In making coking coal, it is seldom possible to add uncleaned fines to the coke oven charge, as their ash content is too high. If, however, the ash content of the fines is reduced to a maximum of 7 or 8 pet, they can be admixed to the washed and crushed small sizes without difficulty. This means, naturally that revenue is increased since the price of coking fines is always higher than the price for dust or uncleaned wet fines. 2) To prevent silicosis and pneumoconiosis, water infusion and spraying of the coal are practiced much more today than ever before. As a result, moisture content of run-of-mine coal has markedly increased and the washery feed coal contains more and more slurry instead of dry dust. The price of slurry, how- ever, is very low, and in many cases it is impossible to sell filtered raw slurry with a moisture content of 20 to 25 pct and, at the same time, 20 to 25 pct of ash. Reduction of the ash content of these slurries improves the possibility of dewatering them and, in this way, also enhances the marketability of this product. 3) The new severe laws and regulations against pollution of air and rivers make it necessary to de-dust coal better than in the past and to reduce the quantity of the waste water from coal preparation plants and their solids content to a minimum. 4) Even if there were no compulsory reasons to clean the fines, flotation will often lead to an increase in the overall yield. Although not the only application, it appears that the treatment of coking fines is the primary field for the flotation process in coal preparation. It must not be overlooked, however, that a series of arguments may be advanced against flotation: 1) Flotation is an expensive process because, in addition to the cleaning operation itself, the dewatering of the froth and the disposal of the tailings is very costly. 2) Operation of a flotation plant requires well trained personnel. 3) Filtered froth has about a 20 pct moisture content and, therefore, if mixed with the cleaned small coal it causes an undesirable increase in water content of the coke oven charge. For this reason it is necessary to take additional measures for dewatering washed small coal and this, of course, entails additional expense. 4) Disposal of flotation tailings involves very difficult problems, particularly in the highly industrialized regions. An investigation covering 32 flotation plants of Western Germany shows the following composition and properties of their feed:

Jan 1, 1961

By L. E. Welch, C. W. MacGregor

THE past 20 years has seen a revolutionary change in the testing of materials at elevated temperatures. This has largely been brought about by the practical importance of the creep problem in the design of equipment for operation at high temperatures. The short-time tension test carried out at elevated temperatures has consequently assumed in many cases only a secondary role compared to the long-time creep test. In many problems, however, a knowledge of the short-time high-temperature properties of a metal is essential. To mention a few cases in which this is so, we might include all hot-forming operations such as rolling, forging, etc., the welding problem if residual stresses are to be computed, the development of new alloys for high-temperature service where, in the initial stages, time does not permit of long duration creep tests, and others. Usually a knowledge of the short-time properties is desired, if only to serve as a background against which to compare creep behavior. In conducting short-time high-temperature tests, it has been almost the universal practice to determine stresses based on the original area and strains referred to the original gauge length which is usually chosen as 2 in. It has been pointed out 1,2 that one of the reasons that the true significance of certain tensile properties is not understood, which perhaps curtails their usefulness, especially when the material is applied [ ] under conditions differing considerably from the test conditions, is that true physical stresses and strains are not determined. It is essential to have a knowledge of true stresses and strains in order to correlate the values present in the tension test with those existing, for example, in hot metal-forming operations and in the general problem of the yielding and failure of metals under combined stress conditions. Stress and strain values based on the original dimensions of the test piece do not exist physically except in the early stages of the test. Since at the present time there is very little information in the literature on true stress-strain relations in the short-time high-temperature tension test it is proposed in the following pages to describe a

Jan 1, 1942

By A. Beeby Thompson

ALTHOUGH the exclusion of foreigners and private owners from participation in the development of the Russian oil fields prevents first-hand information being obtained, both official and private news indicate a growing appreciation of the value of the country's oil resources. Notwithstanding the suppression of that initiative and energy which only ambition can adequately stimulate, the industry is progressing and exports of products are assuming an importance that cannot be disregarded as an economic factor in the world's oil business. The following notes and observations must be regarded mainly as the views of one who has closely followed the fortunes of Russian oil, when considering the changes that have taken place in geological knowledge and oil-field technique, which have so profoundly modified oil-fields methods. Russia is fortunate in having retained the services of a few scientists and technologists whose devotion to science has superseded their personal inclination, and to these few men must be attributed the slow, but nevertheless striking, progress that has been made. The productive oil fields of Russia are centered around the Caspian Sea which, with its connected river system, constitutes such an ideal means of internal distribution for products. From the group of oil fields of which the city of Baku forms a center, oil is pumped to Black town, a suburb of Baku, where all the refineries are situated. The next important group of oil fields is located in the Terek district near Grosny, where refineries are erected and the products are piped or carried by tank cars to Petrovsk for the internal Russian market, or sent to the Black Sea by rail. A third oil field is spread over the province of Uralsk, north of the Caspian Sea, the main port of outlet being Gourief, at the mouth of the River Ural. In Trans-Caspia there are two oil-field centers, one near. Krasnovodsk on Chelekan Island, and one in Central Asia at Ferghana. The product of the former fields is transported to Baku for treatment, while the output of the Turkestan field is refined and consumed locally, mainly by the railway.

Jan 3, 1925

By M. J. Blackburn

The ordering reaction and its effect on dislocation awangements in alloys based on Mg3Cd has been studied by transmission electron microscopy. Ordering occurs by the growth of ordered domains until they impinge, thus producing an antiphase domain boundary (APB) network. In the disordered alloy, slip is confined to the basal plane while in the ordered condition slip occurs on the basal, prism, and pyramidal planes. Superdislocations have been identuied on these planes and their origin and expected spacings are discussed and compared with the observations. The APBs between the dislocation pairs have been resolved and have proved useful in the identification of superdislocations. Observed slip structures are related to the changes in mechanical properties produced by ordering. At high temperatures magnesium and cadmium form a continuous series of disordered hexagonal solid solutions. At lower temperatures three ordering reactions occur; two based on the compositions Mg3Cd and MgCd3 are transformations to DO19-type superlattices while alloys based on the composition MgCd transform to a B19 lattice. The ordering process in alloys near the composition Mg3Cd has been studied by several workers'-4 and it has been shown to be a first-order type transformation. The variation of mechanical properties with the degree of order and temperature have been reported in some detail by Stoloff and Davies.5 It was shown that the disordered alloy was stronger and less ductile than the ordered alloy, the differences being attributed to changes in the number of active slip planes and to the presence of short-range order in the disordered alloy. In this investigation the ordering reaction has been qualitatively followed by transmission electron microscopy. The effect of this ordering transformation on the dislocation arrangements in deformed specimens has been studied in some detail. EXPERIMENTAL Alloys were melted in a stainless-steel crucible under a flux and chill cast; both melting and casting were performed in an argon atmosphere. The ingots were hot-rolled and tensile specimens cut from the resultant strips. Some large-grained specimens were grown by the strain-anneal method. Heat treatment was carried out in inert atmosphere furnaces and in oil baths at the lower temperatures. Thin foils for transmission electron microscopy were produced by electropolishing in a cooled solution (temp = -40°C) containing 50 cu cm of nitric acid and 180 cu cm of methanol at a potential of 10 v. The ordering reaction was followed by transmission electron microscopy, X-ray, and electrical resistivity measurements but this paper will be concerned chiefly with the electron-microscopy results. Much of the work described in this paper was performed on an alloy containing 26.10 at. pct Cd although two of the micrographs are taken from work on a 25.55 at. pct Cd alloy. RESULTS i) The Quenched Solid Solution. Specimens which were quenched from above the critical temperature showed diffuse superlattice reflections. sark-field analysis on these reflections failed to reveal the presence of ordered domains and thus the superlattice reflections were assumed to arise from regions of short-range order. Quenching from temperatures of 400" to 450°C results in the formation of dislocation loops and helical dislocations. Such defects have been observed and analyzed in detail in several hexagonal metals6-' and as the crystallography and interactions of such loops appear similar in this alloy they will not be reported in detail. Fig. 1 shows a high density of loops

Jan 1, 1968

By Jack D. Webber

The successful use of oil well packers requires, in part: an understanding of the pressures which exist at the packer in various applications and an understanding of the characteristics of the various types of packers. It is with these pressures, the resultant forces, and the characteristics of packers. that this paper is primarily concerned. An oil well packer may be defined as a mechanical device for blocking the passage of fluids in an annular space. In the more usual case, the annular space is that between the tubing or drill pipe in a well and the casing, and packers which block such an annular space are broadly referred to as casing packers. In the other case. the annular space is that between the tubing or drill pipe and the walls of an open hole, and packers for blocking this space are generally called formation packers. While the hydraulics involved are essentially the same for casing and formation packers. a greater variety of conditions are encountered in the use of casing packers and only casing packers will be discussed. After a packer has been set and a pressure seal effected between tubing and casing, the packer is comparable to a piston in a cylinder. Pressures acting upon a piston result in forces which will move the piston unless some means is provided to prevent such movement. In the same manner, pressures acting upon a packer will move the packer unless there is present a sufficiently great restraining force. PACKER CLASSIFICATIONS Packers may be classified according to the pressure conditions under which they are capable of blocking the annular space between tubing and casing. Fig. 1 shows schematically two types of packers in common use. These packers are capable of blocking the annular space against the passage of fluids under a differential pressure of significant magnitude only when the pressure in the annular space above the packing element is greater than the pressure below. It may be seen that in Fig. l-a. slips with teeth which bite into the casing and prevent downward movement are provided. In Fig. 1-h. an anchor prevents downward movement. In each case, there i-only the tubing to prevent upward movement when differential pressures act to move the packers upwardly. Packers which hold only a significant differential pressure acting downwardly have been in use since the early days of the oil industry and will hereafter be referred to as conventional type packers. In many packer applications operating conditions will 1.crult in differential pressures across the packer which will at times act to move the packer upwardly, and at other times, act to move the packer downwardly. For these applications, designs are available which will block the annular space and resist movement in either direction. Fig. 2-a shows schematically a packer of this type which is designed to be run into a well and set, and removed when desired by merely pulling the tubing. It will be noted that two sets of slips are provided-— one set above the packing element to prevent upward movement, and another set below the packing element to prevent downward movement. This packer is built around a mandrel which is essentially a part of the tubing. and which is free to move longitudinally within certain limits through the set packer. Fig. 2-b shows schematically a permanent type packer which is capable of holding pressures from either direction. Here again, two sets of slips are provided to prevenl movement of the packer. This packer is designed to become virtuallv a part of the casing when set and it is made of drillable material so that it may be drilled out when its removal is desired. The seal nipple shown effects a pressure seal between the tubing and the packer. This seal nipple is a part of the the tubing, and the nipple and tubing may be withdrawn from the well without disturbing the packer. It should be noted that these figures are not representative of all available packers which are designed to hold pressures from both above and below. Packers which resist movement in either direction will hereafter be referred to as universal type packers. There is a third type of packer in general use and this type is designed to block the passage of fluids when the pressure below the packing element ii greater than that above. This type is provided with slips which prevent upward movement of the packer and is somewhat similar to a conventional type packer run upside-down. Packers designed to hold pressure only from below are made in a variety of designs and are usually owned and operated by service companies.

Jan 1, 1949

By Jack D. Webber

The successful use of oil well packers requires, in part: an understanding of the pressures which exist at the packer in various applications and an understanding of the characteristics of the various types of packers. It is with these pressures, the resultant forces, and the characteristics of packers. that this paper is primarily concerned. An oil well packer may be defined as a mechanical device for blocking the passage of fluids in an annular space. In the more usual case, the annular space is that between the tubing or drill pipe in a well and the casing, and packers which block such an annular space are broadly referred to as casing packers. In the other case. the annular space is that between the tubing or drill pipe and the walls of an open hole, and packers for blocking this space are generally called formation packers. While the hydraulics involved are essentially the same for casing and formation packers. a greater variety of conditions are encountered in the use of casing packers and only casing packers will be discussed. After a packer has been set and a pressure seal effected between tubing and casing, the packer is comparable to a piston in a cylinder. Pressures acting upon a piston result in forces which will move the piston unless some means is provided to prevent such movement. In the same manner, pressures acting upon a packer will move the packer unless there is present a sufficiently great restraining force. PACKER CLASSIFICATIONS Packers may be classified according to the pressure conditions under which they are capable of blocking the annular space between tubing and casing. Fig. 1 shows schematically two types of packers in common use. These packers are capable of blocking the annular space against the passage of fluids under a differential pressure of significant magnitude only when the pressure in the annular space above the packing element is greater than the pressure below. It may be seen that in Fig. l-a. slips with teeth which bite into the casing and prevent downward movement are provided. In Fig. 1-h. an anchor prevents downward movement. In each case, there i-only the tubing to prevent upward movement when differential pressures act to move the packers upwardly. Packers which hold only a significant differential pressure acting downwardly have been in use since the early days of the oil industry and will hereafter be referred to as conventional type packers. In many packer applications operating conditions will 1.crult in differential pressures across the packer which will at times act to move the packer upwardly, and at other times, act to move the packer downwardly. For these applications, designs are available which will block the annular space and resist movement in either direction. Fig. 2-a shows schematically a packer of this type which is designed to be run into a well and set, and removed when desired by merely pulling the tubing. It will be noted that two sets of slips are provided-— one set above the packing element to prevent upward movement, and another set below the packing element to prevent downward movement. This packer is built around a mandrel which is essentially a part of the tubing. and which is free to move longitudinally within certain limits through the set packer. Fig. 2-b shows schematically a permanent type packer which is capable of holding pressures from either direction. Here again, two sets of slips are provided to prevenl movement of the packer. This packer is designed to become virtuallv a part of the casing when set and it is made of drillable material so that it may be drilled out when its removal is desired. The seal nipple shown effects a pressure seal between the tubing and the packer. This seal nipple is a part of the the tubing, and the nipple and tubing may be withdrawn from the well without disturbing the packer. It should be noted that these figures are not representative of all available packers which are designed to hold pressures from both above and below. Packers which resist movement in either direction will hereafter be referred to as universal type packers. There is a third type of packer in general use and this type is designed to block the passage of fluids when the pressure below the packing element ii greater than that above. This type is provided with slips which prevent upward movement of the packer and is somewhat similar to a conventional type packer run upside-down. Packers designed to hold pressure only from below are made in a variety of designs and are usually owned and operated by service companies.

Jan 1, 1949

Executive Committee, Board of Directors Grover J Holt, Chairman, C E Reistle, Jr , Vice-Chairman, A W Thornton, A B Kinzel, J L Gillson Finance Committee, Board of Directors Andrew Fletcher, Chairman, R B Caples, Gail F Moulton Investments Erle Daveler, '60, Chairman, Henry Krumb, '59, John Warren, '60, C R Dod¬son, ex off as Treasurer, Andrew Fletcher, ex off as Chairman, Finance Committee Endowment Andrew Fletcher, Chairman, N G Alford, E V Daveler, W J Coulter, J V N Dorr, R B Gilmore, J B Haffner, 0 H Johnson, D H McLaughlin, J R McMillan, L F Reinartz, C E Weed, Wilfred Sykes, J R Suman Honorary Memberships L F Reinartz, Chairman, C E Reistle, Jr , H DeWitt Smith, ex off as Past Presidents of AIMS, Grover J Holt, ex off as President AIMS, P D Merica, '59, Henry Krumb, '58, M L Haider, '60, D H McLaughlin, '61

Jan 1, 1957

By D. E. Spiller

Introduction Precious metals recovery from ore can generally be accomplished using gravity concentration, flotation, and/or hydrometallurgical (leaching) techniques. The objective of this paper is to show why gravity concentration can be an important part of recovery systems that employ leaching as the primary unit operation. A brief discussion of modem gravity concentration equipment is also presented. Discussion Gravity concentration of ores has generated increasing interest in recent years. Reasons for this interest include: • Gravity concentration is environmentally attractive. There is little or no use of reagents. Hence, it is relatively nonpolluting. • The cost of cyanide has continued to increase. Therefore, cost savings may be realized whenever leaching feed tonnage can be reduced by preconcentration. • Compared to flotation and leaching, gravity equipment costs are low per processed ton. Field installation costs for gravity circuits usually are less because many' units are supplied as self-contained modules. Also, the cost required to supply services, particularly power, to a gravity plant site are also less. In situations where preconcentration at coarse particle size is applicable, significant grinding equipment savings may be possible. • Gravity circuit operating costs are also relatively low compared to typical flotation and leaching circuits. Reagents, power, maintenance, and manpower savings in a well-engineered gravity plant may be realized. Again, if grinding is reduced, significant power and steel (media and liners) savings are possible. •In recent years, more efficient gravity concentrating devices have been developed. Benefits to Precious Metal Leaching Gravity beneficiation can complement precious metal leaching in two ways. First, the recovery of coarse liberated values before leaching may reduce leach time requirements and may reduce reagent consumption. Second, gravity preconcentration can reduce the size of a leach plant by decreasing the quantity of material to be leached. Coarse gold and silver have been shown to leach rather slowly. Kameda (1949) and Habashi (1967) have investigated the kinetics of cyanide leaching systems. They concur that in a heterogeneous reaction, the rate of gold and silver dissolution is directly proportional to the surface area. Thus, the instantaneous rate of dissolution for spherical 0.37 mm (400 mesh) gold is theoretically -25 times faster than for the same amount of gold at .841 mm (20 mesh), based on data from Fuerstenau, Chander, and Abouzeid (1979). Conversely, coarse liberated, +.841 mm (20 mesh), gold is more readily recovered by gravity concentration than is fine, -.037 mm (400 mesh) gold. Therefore, it is apparent that the two recovery systems complement one another. Figure 1 data demonstrates the potential synergism. A sample of - 3.327 mm (6 mesh) Nevada gold-bearing ore was cyanide leached using conventional bottle-roll test procedures. Gold extraction was determined as a function of leaching time. A second sample split from the same leach feed material was hand jigged to remove a coarse heavy mineral fraction, including virtually all of the +.210 mm (65 mesh) liberated free gold. This second sample, with the coarse gold and heavy minerals removed, was subjected to an identical cyanide leach procedure. Figure 1 presents the resulting comparative extraction data. Note that the percent gold extraction for the sample containing no +.210 mm (65 mesh) free gold includes the coarse gold recovered by gravity. The data show that the sample containing coarse gold required about 72 hours of leaching time to achieve 80% extraction. This compared to about 22 hours of leaching time for 80% gold recovery from the sample that contained only -.210 mm (65 mesh) free gold. Thus, there was a 69% reduction in leaching time. The improved extraction data is not wholly attributable to coarse gold removal, but rather it was the combination of gold removal and rejection of other heavy mineral cyanide consumers or leach retardants. Further investigation was not warranted at this time. Preconcentration is the second manner in which leaching systems can benefit from gravity concentration. The premise is that preconcentration can reduce the quantity of leach feed, which, in turn, may reduce leaching costs. Figure 2 presents preliminary data developed by CSMRI for US Minerals Exploration (USMX). Centennial Exploration Inc., in agreement with USMX, is proceeding with evaluations to determine the suitability of various processing schemes for recovery of gold values from the Montana Tunnels property. The data shows how the ore can be preconcentrated by gravity techniques to result in a reduced feed tonnage to secondary extraction techniques, presumably flotation or cyanide leaching. Testing has shown that Reichert cones, followed by treating the cone concentrate on spirals, can deliver about 88% gold recovery in about 13% weight, that is, 87% weight rejection. Consequently, fine grinding and reagent costs are attributable to only 13% of the plant feed rate. Cost data is not yet available, but the potential exists for significant cost savings.

Jan 1, 1985

By W. E. C. Eustis

1st. THE fine iron ore is mixed with a sufficient proportion of fine coking coal, and is coked in any of the ordinary methods for making coke. The effect of this is to convert the iron oxide into sponge in such a shape that the usual trouble of oxidation is avoided. 2d. The resulting mixture of coke and sponge is melted down in an ordinary cupola, the coke furnishing more than sufficient fuel for that purpose. I may briefly point out here that in the first place the iron is sponged, and this sponge, as is well known, contain-, no phosphorus or silicon when the reduction takes place at a low temperature; and in the second place this sponge is melted down in a cupola in which there is no zone of reduction for phosphorus or silicon, and that con¬sequently the resulting iron should be free from both of these impu¬rities. 3d. The liquid sponge, now carburized, is run into an open-hearth furnace, where the requisite degree of hardness or softness is obtained by adding some of the fine ore, and the usual dose of ferronmanganose. I have merely given above the rough outlines of the process, but it is my intention, as early as possible, to bring the process more fully before the Institute.

Jan 1, 1881

By Dale A. Vaughan, Oliver M. Stewart, Charles M. Schwartz

Solid-solubility limits at 1500°, l000q and 500°C for carbon, nitrogen, and oxygen in high-purity tantalum were determined by X-ray lattice-parameter methods. For carbon, the solubility was found to be 0.17 at. pct at 1500°C, and less than 0.07 at. pct at 1000°C. A nitrogen solubility of 3.70 at. pct at 1500° C decreases linearly with temperature to 2.75 at. pct at 1000°C, and 1.8 at. pct at 500°C. In the case of oxygen, the solubility was found to be 3.65 at. pct at 1500°C, 2.95 at. pct at 1000°C, and 2.5 at. pct at 500°C. The phases Ta2C, the low-temperature modification of Ta205, and Ta,N of unknown composition but which has a superlattice structure based upon the original bcc tantalum lattice have been identified as the initial precipitates in the respective systems. Metallographic methods were employed to verify the X-ray analyses. The etching behavior of Ta is discussed in terms of lattice i?rzperfections and precipitate phases. The excellent fabricability, high melting point, and nuclear properties of tantalum are responsible for interest in this refractory metal. Data on the solid solubility of the interstitial elements (oxygen, nitrogen, and carbon) in tantalum and on the precipitate phases are somewhat limited. The significant contributions are discussed below. Because the purity of electron-beam melted tantalum (only recently available) is considerably higher than that used in previous studies, the present investigation was initiated. Gebhardt et all-3 have investigated the tantalum-oxygen and tantalum-nitrogen systems with particular reference to the changes in physical properties and to the rates of reaction between these gases and the metal. The solubility of oxygen in tantalum was reported2 to be 3.7 at. pet at 1500°, 2.3 at. pet at 100O°C, and 1.4 at. pct at 750°C. Schonberg4 reported that several oxide phases (Ta40, Ta,O, TaO and Ta,05) exist while X-ray studies by Gebhardtl showed only two oxides, Ta,05 and an unidentified phase which was associated with a platelet-type precipitate. La-gergren and Magneli,' however, questioned the existence of compounds other than the two allotropic modifications of Ta,05 for the tantalum-oxygen system. In the case of nitrogen, the solubility was estab- lished by Gebhardt3 to be of the order of 7 at. pct at 1800°c. The solubility was reported to decrease rapidly with temperature, and, although no limits were established, a precipitate phase was observed by Gebhardt except when the high-nitrogen specimens were cooled very rapidly from the reaction temperature of 1800c. He reported the initial precipitate phase to be a tetragonal distortion of the bcc tantalum lattice while Schonberg6 reported the phase lowest in nitrogen Jo be a cubic super-lattice with a cell size of 10.11 A. Two other nitride phases, Ta,N and TaN, were reported; these appear to be isomor-phous with the carbides of tantalum. The tantalum-carbon system was investigated by Ellinger7 and by Lesser and Braurer. Two compounds, Ta,C and TaC, were reported to exist, each with a range of composition. The solubility of carbon in tantalum was found to be practically nil at all temperatures. Thus, of the interstitial elements which are present in small amounts in high-purity tantalum, carbon might be expected to form precipitates. The present investigation was initiated to obtain additional data on the solid-solubility limits of these interstitials at 1500°, 1000°, and 500' with particular emphasis on the distribution and the identification of the precipitate phases. EXPERIMENTAL WORK AND RESULTS In the present investigations of the solid solubility and of the precipitate phases in the systems tantalum-nitrogen, -oxygen, and -carbon, high-purity tantalum was reacted with high-purity gases, homogenized at 1800°c, and annealed at and quenched from 1500°, 1000,

Jan 1, 1962