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By W. G. Matteson

THE origin of the salt domes of the Gulf coastal plain has been investigated by many of the most able geologists, but the problem cannot be said to have been satisfactorily solved. Since 1860, numerous theories have been presented, only to be discarded, at least in part, as more complete information revealed their fundamental weakness. Real progress toward solution dates from 1902, when Hill' advanced the theory of secondary deposition of the domal materials from saturated solutions of hot saline waters ascending from great depths under hydrostatic head along structural lines of weakness. Shortly thereafter, Harris,2 using Hill's hypothesis as a basis, explained the doming and pronounced uplift associated with these salt cores as the result of forces exerted by growing salt crystals. This was a marked advance over the ideas of Coste3 and Hager,4 since no. evidence of igneous intrusives, as they assumed to explain the uplifts, had been found associated with the domes. Harris5 developed his theory until it offered such apparently plausible explanations of so many details of dome phenomena that his hypothesis and conclusions received widespread acceptance, despite some serious objections, and today his theory, somewhat modified, is considered by many able investigators to be the best explanation of, the origin of these domes. The immense production of oil per acre, the recognition of the high lubricating quality of the oil, the development and recognition of the efficiency and advantages of oil-burning vessels, with the, subsequent

Jan 2, 1921

By D. J. Wynnemer, G. W. Preckshot

Precise electromotive force measurements have been made on the zinc-cadmium system over the temperature range 700° to 900°C. Activity coefficients, partial free energies, enthalpies, and entropies have been determined .for the entire composition range. The integral heat of mixing is positive and compares favorably with calorimetrically determined values. Vapor-liquid equilibrium compositions were determined .for a total pressure of 1 atm and these agree well with previous values determined in other ways. The use of electromotive force measurements to obtain thermodynamic data for liquid metal systems is a simple and well-known method. Several reviews of the various experimental methods and results have been published.2,3,11 However, most of the past work using this technique was carried out at temperatures slightly above the melting point of the alloy system where alloy composition changes due to vapor transport and increased metal solubility in the electrolyte are not important factors. One advantage of extending the electromotive force measurements up to and including the normal boiling point of the alloy is that it is then possible to evaluate the vapor-liquid equilibrium of the alloy at various pressure levels up to 1 atm. A detailed discussion of the thermodynamics of reversible electromotive force cells can be found in most advanced physical chemistry or chemical thermodynamic textbooks. The expression stating the inter-relation of the electromotive force and the thermodynamic functions is the Gibbs-Helmholtz equation.

Jan 1, 1962

By A. M. Talbot, John T. Norton

TheRe is still considerable controversy as to the exact nature of the mechanism of the age-hardening process, in spite of the many experiments already performed. For this reason, a considerable number of typical systems should be examined in detail and their results correlated. Furthermore, the methods of studying the changes that take place during the progress of this phenomenon should be carefully scrutinized and the different methods applied to the same samples, preferably at the same time. The experiments described in this paper are presented to supply information on one age-hardening system and to show how the various methods of investigation compare in their indication of what has happened. In brief, the progress of aging in magnesium alloys containing about 10 per cent by weight of aluminum at different temperatures was followed by measurements of hardness, electrical resistivity, dilation and lattice parameter, and by microscopic observation. Previous Work Meissnerl,$ Archer?, and Gann3 have investigated the changes in mechanical properties of magnesium-aluminum alloys during aging and have shown the optimum condition for the age-hardening treatment. Meissner's results are particularly interesting because when replotted so that they represent hardness as a function of aging time, the curves of 125" and 150" C. show two hardness peaks. This result was not confirmed in the present work. Schmid and Siebe14 have reported an investigation that is similar to the present one but it was not published until the present work had

Jan 1, 1936

By H. Hu

Observations were made on the recrystallization of a 70 pct cdd-rolled silicon-iron crystal with an initial orientation of (113) [332]. Its polygonization and recrystallization characteristics were studied. Results indicated that re crystallization tendency of the deformed crystal is much weakened by the polygonization of the matrix. Complete recrystallization in such specimens is achieved by the growth of recrystallized grains of sufficient size and of the right orientations in relation to the matrix. Evidence was also furnished which suggests that the difference in the re-crystallization tendency is a result of the difference in the severity of lattice bending rather than the difference in orientation of the deformation texture. DUNN and Koh1,2 have made an extensive study on the rolling and annealing textures in silicon-iron crystals. Their results indicated that the recrystallization tendency can be widely different in crystals with different orientations. A particularly interesting example of their results was a crystal with an initial orientation of (113) [332], which developed a deformation texture of (001) [110] after 70 pct cold-rolling. Recrystallization in this crystal took long time anneals at high temperatures. Other crystals having different orientations recrystallized very rapidly. Wiener and corcoran3 have observed the retention of the (100) [011] deformation texture in a low-temperature annealed specimen of a commercial silicon-iron alloy, corresponding to areas of light-etching low-angle boundaries in the annealed struc-

Jan 1, 1960

By Milan Matula

One of the main characteristics of the development of rock mechanics in some countries is a close cooperation between experts in rock mechanics and workers in related fields, including soil mechanics and engineering geology. The purpose of this chapter is to outline the contribution that engineering geology can make to rock mechanics and to present a few examples of engineering geology studies that have been used in solving some practical rock mechanics problems. Engineering geology investigations dealing with the influence of geological factors on the physical properties of rock materials and rock masses fall into three main categories : 1) Systematic study and correlation of the physical properties of the main rock types with the petrogenetic evolution that caused the differences in the properties of these various rock types. 2) Study of the heterogeneity and anisotropy of both rock materials and rock masses. 3) Delimitation of rock masses which are approximately uniform in physical properties (quasihomogeneous units). Delimiting of the quasihomogeneous rock masses is the main contribution that the engineering geologist can make to rock mechanics. This delimiting is based on the evaluation of many complex geologic factors, not on test results alone, and therefore is most effectively done by trained engineering geologists. The foregoing types of studies are being used in Czechoslovakia for several purposes, including : 1) the compilation of regional engineering petrologic data-that is, the systematic definition of the main rock types of the country in terms of their representative physical characteristics;

Jan 1, 1970

By William Fink

THIS paper is the nineteenth of a series from the Aluminum Research Laboratories, presenting the results of the investigations of equilibrium relations in aluminum-base alloys made from electrolytically refined aluminum. In previous papers equilibrium) relations have been deter-mined and correlated for 12 binary systems. Equilibrium relations have also been determined for portions of the aluminum corners of three ternary systems (aluminum-iron-silicon, aluminum-magnesium-silicon and alu-minum-copper-magnesium). The object of the present paper and those to follow is to increase our knowledge of the aluminum corner of the more important ternary systems. In 1926 Dix and Keith? suggested a new method for designating the phases encountered in alloy systems. The system has been used to a very limited extent 1,2,3. The system has since been slightly modified and will be used in this and future papers. In the system as modified, a phase is designated by placing in parentheses the chemical symbols of the elements essential to the formation of that phase. The symbols in the parentheses are separated by dashes in order to clearly distinguish them from a chemical formula. Elements that are not necessary to the formation of the phase in question, but which may be present in solid solution, are not indicated in the designation. If two or more phases would have the same designation according to these rules, they are dis-tinguished by prefixing Greek letters, and are definitely identified by X-ray diffraction patterns.

Jan 1, 1936

By P. Ramachandrarao, T. R. Anantharaman

CONSIDERABLE interest has lately been evinced as regards the nature of chill zones in solidified metals and alloys. Biloni and Chalmersl were the first to show through their study of segregation substructures in some nonferrous alloys that the formation of the dendritic region may be preceded by a diffusionless solidification process, viz., predendritic solidification. Subsequently Bower and Flemings2 tried a special solidification technique wherein the liquid was drawn into a narrow copper mold with polished surfaces and concluded that convection might trigger some multiplication mechanism leading to grain refinement. Using uncoated and partially coated surfaces for molds in the Bower-Flemings technique as well as in conventional molds, Biloni and Morando3 have very recently brought out the importance of the rate of heat extraction on the mechanism of solidification. We report here on the surface structures and substructures observed in a Sn-1 wt pct Pb alloy solidified at even higher cooling rates (riz., l05 to l07 ºc per sec) than those employed by earlier workers. The alloy was made by melting tin (99.99+ pct) and lead (99.9+ pct) in a silica tube under vacuum. Small quantities of the homogenized alloy (0.5 to 1.0 g) were then quenched (or splat-cooled) from the melt by the "gun technique" developed by Duwez et al.4 The thickness of the resultant foils varied from specimen to

Jan 1, 1970

By R. A. Meussner, R. T. DeHoff, F. N. Rhines

ZINC diffuses through copper more rapidly than does tin. Accordingly, when a ternary diffusion couple is made, by bringing an 0 copper-zinc brass into contact with an a copper-tin bronze at fixed high temperature, it is to be expected that zinc will diffuse into the bronze faster than tin diffuses into the brass. Adjacent to the brass side of the couple the total alloy content (zinc plus tin) should diminish, therefore, while next to the bronze side the alloy content should increase. Since the path of compo- sition change must be continuous, in a single-phased alloy, it should follow a curved and, in general, an S-shaped course. The realization of this prediction is demonstrated in Fig. 1, where the composition paths of two ternary diffusion couples are plotted on the appropriate isotherm of the copper-tin-zinc phase diagram. The diffusion couples were both made from a binary copper-tin alloy analyzing 5.0 pct tin placed against binary copper-zinc alloys analyzing 18.9 and 29.3 pct Zn, respectively. These alloys were produced from electrolytic grades of copper and zinc and a pure grade of straits tin, melted under borax in clay-graphite crucibles and cast in a vertical iron mold. Cylindrical pieces 1 in. in diam and 1 % in. long were machined from the casting and were faced by metallographic polishing to good matching end surfaces. Pairs of the cylindrical pieces were held

Jan 1, 1959

By N. B. Gray, R. V. Culver, W. S. Boundy, N. W. Stump

The kinetics of sulfation of single crystals of lead sulfide to lead sulfate have been studied between 969" and 1073°K in gas atmospheres of known composition using a thermobalance technique. The data are described by an equation derived on the basis that diffusion outward through the Product layer is the major controlling step. The rate of sulfation is linearly related to the logarithm of the sulfur trioxide partial DESPITE its industrial significance the oxidation of lead sulfide has received limited attention. The oxidation reactions have been studied using beds, briquettes, single crystals, or thin films of lead sulfide. Lead oxide and lead sulfate (PbSO,) were formed when Mclntoshl and Gardner2 roasted beds of galena pressure and the temperature coefficient of reaction is 40 ± 5 kcal per g mole. Gold marker experiments show that the sulfate layer grows by outward movement of ions through the sulfate layer. Initially the PbSO, adheres to the PbS but later forms an irnpewious spheroidal envelope; PbS vaporizes and pb2' ions diffuse through the envelope to react at the external surface. in air at temperatures up to 800°C. In a more extensive investigation, Tchizhykov3 obtained Pb, PbO, and PbS04 in accordance with Eqs. [1] to [4], when a bed of -200 mesh galena was oxidized in O2-N2 mixtures at 700° to 900°C.

Jan 1, 1968

By John Carter Anderson

The theory of a zonal deposition of ores from ascending solutions which were differentiation products of a cooling magma, first propounded by Spurr,l in a measure explained by Lindgren,2 and recently re-emphasized by kemp,3 while perhaps accepted in principle by many mining geologists, so far has not been accepted as capable of practical application in the study and development of ore deposits. From his observations, the writer is convinced that there are laws governing the primary deposition of ores which, when properly worked out, will be of greatest economic value; and that the application of this knowledge to the development of new mines will mark an advance in the mining industry similar to that following the working out and application of the theory of secondary enriehiment. That there has been a tendency to a zonal distribution in the formation of ore deposits, by which the ores of one metal have been precipitated from tile mincralizing solutiolis at a greater distance from the source than those of another, cannot be disputed; and the nature of this zoning in a given deposit or district has been frequently described.4 But that a selection precipitation of the ores of two or more metals, other than lead and zinc, in successive zones may have taken place in a single deposit within limits economically possible of exploration is not generally recognized or admitted.

Jan 1, 1923

By John Carter Anderson

The theory of a zonal deposition of ores from ascending solutions which were differentiation products of a cooling magma, first propounded by Spurr,l in a measure explained by Lindgren,2 and recently re-emphasized by kemp,3 while perhaps accepted in principle by many mining geologists, so far has not been accepted as capable of practical application in the study and development of ore deposits. From his observations, the writer is convinced that there are laws governing the primary deposition of ores which, when properly worked out, will be of greatest economic value; and that the application of this knowledge to the development of new mines will mark an advance in the mining industry similar to that following the working out and application of the theory of secondary enriehiment. That there has been a tendency to a zonal distribution in the formation of ore deposits, by which the ores of one metal have been precipitated from tile mincralizing solutiolis at a greater distance from the source than those of another, cannot be disputed; and the nature of this zoning in a given deposit or district has been frequently described.4 But that a selection precipitation of the ores of two or more metals, other than lead and zinc, in successive zones may have taken place in a single deposit within limits economically possible of exploration is not generally recognized or admitted.

Jan 1, 1923

By Charles S. Barrett, Robert F. Mehl, Dana W. Smith

The Widmanstatten figures found in the steels have been long recognized and in some aspects carefully studied,' especially as they occur in cast hypoeutectoid alloys. Aside from the practical importance of the structures obtained in the steels by various heat treatments, a study of the characteristics of these figures is interesting because of the rich opportunity the system affords to obtain new data on the mechanism of segregation from solid solutions. This opportunity is twofold: first, by changing composition within the austenite range the proeutectoid precipitate may be changed from that of ferrite to that of cementite, thus offering the same opportunity for changing the type of precipitate while maintaining the same basic lattice as that afforded by the Cu-Zn alloys;2 and second, the eutectoid inversion leads upon drastic quenching to the formation of martensite, a Widman-statten figure of unique interest from the crystallographic viewpoint, particularly in comparison with those formed on slow cooling.3 We have, therefore, two types of structure to study: that formed on slow cooling of hypoeutectoid and hypereutectoid alloys, and that formed on quenching hypoeutectoid, eutectoid, and hypereutectoid alloys. For each of these types of structure we require the crystallographic plane in the mother austenite along which the precipitate forms (we shall see that the precipitates in these alloys are invariably platelike in form), and also the orientation of the precipitate upon this plane. Some of these

Jan 1, 1933

By M. G. F. Söhnlein

IN THE metallurgical treatment of sulfide silver-tin ores mined at Oruro, Potosi, and Chocaya, the most important and difficult step is chloridizing-roasting. The ores are chiefly mined from veins in rhyolite, a detailed description of which can be found in most textbooks on ore deposits. The chief gangue minerals are Pyrite and quartz, and the silver content is derived from tetrahedrite, jamesonite, stibnite, and cylindrite. Most of the tin is present in the form of a rather impure cassiterite, which forms microcrystalline aggregates of varying richness with quartz and pyrite; occasionally, some tin is found as stannite, cylindrite, and other complex sulfantimonates. The silver content of the minerals that compose the ore is approximately as follows: Pyrite, 3 to 5 oz. per ton; jamesonite, 30 to 50 oz. per ton; stibnite, 30 to 150 oz. per ton; cylindrite, 200 to 300 oz. per-Jon; tetrahedrite, 500 to 3000 oz. per ton. Occasionally, some ruby silver ore is found, but it is very rare. In the mines of Oruro, which are the deepest in the sulfide zone, tetrahedrite has nearly disappeared, stibnite, jamesonite, and, in the deepest levels, cylindrite taking its place. At present, there are six mills treating this ore, two at Potosi, two at Chocaya, one at Poopo, and one at Machacamarca. The ore is crushed dry, given a chloridizing roast, leached with water and hyposulfite solution (or with brine) to extract gold, silver and copper, and concentrated for tin with or' without regrinding.

Jan 8, 1920

By A. G. McGregor

DURING the past 5 years, five new copper-smelting plants have been built and put into operation in the State of Arizona. The monthly copper output from these plants averages from 5,000,000 to 18,000,000 lb. Previously, there never was as much activity in copper-smelting plant construction in the same length of time in all the rest of the world. Naturally, in this amount of work, some new problems were met and new features in plant design and. equipment developed. Some of these features are described in this paper. CONCENTRATE HAULING, UNLOADING AND SAMPLING SYSTEM (a) Concentrate Car The International Smelting Co. has provided at its plant at Miami specially designed cars for hauling the concentrates from the mills of the Inspiration Copper Co. and the Miami Copper Co.. The car has a bottom that is readily made tight to hold flotation concentrates and is quickly and cheaply unloaded. Figs. 1, 2 and 3 show views and details of the car. The main feature of this car is the slot in the bottom throughout its length, which is closed by means of short planks that overlap like ship-lap as shown by Fig. 1. At one end of the car an iron gate operated by a screw and hand wheel is provided, which clamps or presses the planks together, making the bottom tight. A removable tapered plug rests vertically over this gate when the loading of the concentrates at the mill commences.

Jan 8, 1916

By G. Kimmel, A. Bar-Or

The rate of nucleation and the rates of both lateral and longitudinal growth of martensite plates (needles) in b—a transformation were determined as a function of temperature, in various U-Cr alloys. The activation energies for nucleation and both modes of growth were calculated from the experimental results. The identical values for lateral and longitudinal growth clearly indicate that both are controlled by the WHITE,' Mott and Hines and Holdeen3 showed that characteristic martensite plates (needles) appear in U-Cr alloys during the transformation 8 —0 in the lower temperature range (up to -300°C). Holden pointed out that the rate of growth of the individual martensite plates under isothermal conditions is same mechanism. Lomer's suggestion that single-atom movement over subatomic distances controls the specially slow growth of martensite receives further support from the present kinetic study, which shows that the growth rate can be described quantitatively by known formulas for the growth rate in processes involving single-atom movement. very slow, and suggested that this is due to the slowness of the relief of the stresses engendered during the growth of the individual plates. lomer4 attributed the slow growth to the complexity of the atomic adjustment at the growing interface b/(u. In the present work the rates of nucleation and growth of martensite plates in U-Cr alloys were studied by direct observation, in order to elucidate the mechanism which controls their characteristic slow growth.

Jan 1, 1968

By J. L. Bray

IT is well known that iron markedly improves the physical properties and casting characteristics of aluminum bronzes. The use of 1 to 4 per cent iron as the principal modifying addition has become common practice in many foundries melting aluminum bronzes. Although the beneficial effects of iron are unquestioned, there is some uncertainty regarding the structural changes caused by it in the basic copper-alumi-num system. It is agreed that a new constituent appears in abundance when the iron content reaches 2 to 4 per cent. This constituent, which frequently occurs in shapes resembling clover leaves, is sometimes assumed to be an aluminum-iron intermetallic compound. If this were correct we might expect a change in the structural relationships of the matrix in the direction of decreased aluminum content. On the other hand, it has been reported that iron has a negligible effect in altering the fundamental relationships of copper-aluminum alloys1. Others2,3 have reported an additive coefficient. Apparently it will be necessary to know the equilibrium relationships between the phases of the copper-aluminum-iron alloy system to establish any such theory as fact. When this has been done it may very well be that a further revision in the structural relationships may be necessary to describe the changes to be expected in commercial cast alloys. It was with this latter problem before them that the authors attempted to

Jan 1, 1936

By Thomas Cox

The following compilations are made from a series of investigations and are used to present the subject in an unbiased manner, as the writer does not represent any company or financial interest. The present situation is complex. The producers are hard pressed by reason of the low price of crude, while the independent refiner is little better off, because of the corresponding cut in price of refined products, except on occasional contracts. If the real costs are analyzed, it will be seen that the land speculators and the lessors—royalty owners—make the larger profits and not the struggling legitimate operator or independent refiner. The present-day (October, 1922) posted prices per barrel for crudes are Kansas, Oklahoma, Mexia, Gulf Coast, and Louisiana..... $1.25 Healdton............................................. 0.75 Northern Texas and Central Texas...................... 1 . 50 Pennsylvania......................................... 3.00 Wyoming, Elk Basin.................................. 1.25 Wyoming, Salt Creek................................ 0.70 California Base..................................... 0.60 These prices are at the well. In addition, crudes must be gathered and transported to refinery (by pipe line or tank cars), refined, and the refined products marketed. These crudes are of various gravities, ranging within a narrow margin for each field or district, so that averages are not difficult to deduce, and it is these averages that really determine the average operating conditions. In order to show the present realizations, the prices and costs now obtaining are listed against the average yields; the figures are also adjusted VOL. urn.----71

Jan 1, 1923

By Thomas Cox

The following compilations are made from a series of investigations and are used to present the subject in an unbiased manner, as the writer does not represent any company or financial interest. The present situation is complex. The producers are hard pressed by reason of the low price of crude, while the independent refiner is little better off, because of the corresponding cut in price of refined products, except on occasional contracts. If the real costs are analyzed, it will be seen that the land speculators and the lessors—royalty owners—make the larger profits and not the struggling legitimate operator or independent refiner. The present-day (October, 1922) posted prices per barrel for crudes are Kansas, Oklahoma, Mexia, Gulf Coast, and Louisiana..... $1.25 Healdton............................................. 0.75 Northern Texas and Central Texas...................... 1 . 50 Pennsylvania......................................... 3.00 Wyoming, Elk Basin.................................. 1.25 Wyoming, Salt Creek................................ 0.70 California Base..................................... 0.60 These prices are at the well. In addition, crudes must be gathered and transported to refinery (by pipe line or tank cars), refined, and the refined products marketed. These crudes are of various gravities, ranging within a narrow margin for each field or district, so that averages are not difficult to deduce, and it is these averages that really determine the average operating conditions. In order to show the present realizations, the prices and costs now obtaining are listed against the average yields; the figures are also adjusted VOL. urn.----71

Jan 1, 1923

By H. N. Lawrie

This study was undertaken on account of the lack of definite knowledge concerning the influence of bismuth on wire-bar copper, and the small elimination of bismuth from copper-matte during the smelting-operations. The early workers who studied the influence of bismuth on copper confined their investigations to malleability and ductility—two physical properties which are related to the others so intimately that their determination is of primary importance. Karsten and Levo1,² using bending- and mealleability-tests, seem to have been the first to take up the subject, and while their results are incomplete, they agree in the main with the later work of Hampe.3 The bending-tests used by the first investigators consisted in bending the specimen until it failed. The malleability-tests were made by beating the material to a knife-edge with a hammer. Hampe not only determined the percentage of bismuth which would cause red-shortness and cold-shortness of the alloy, together with other influences of bismuth on the malleability and ductility of copper, but also took up the influence of the bismuth protoxide, BiO, on copper, and of bismuth sesquioxide, Bi,O,, on the copper protoxide, CuO. Hampe's conclusioris of the influences of these two latter compounds of bismuth on copper are as follows : "If the protoxide of bismnth be alloyed with metallic copper, it is not changed to metallic bismuth, but remains mechanically distributed throughout the copper.

Jan 1, 1910

By Fred Chappell

Pyrophyllite, a hydrous aluminum silicate, physically similar to talc, receives its name from the Greek word Pyr, for fire and phyllite, a rock or stone. Firestone refers to its first recorded use as firestones or hearthstones. Composition and Properties Pyrophyllite is an aluminum silicate A12O34SiO2H2O (alumina 28.3 pct, silica 66.7 [ ] pct, water 5.0 pct) (Table 1). Vanderbilt1 gives pH value of pyrophyllite as 5.6 to 8.4. Pyrophyllite is usually white or cream, though it may be found in shades of pale green, pale yellow, buff or light gray, and in darker shades and other colors principally due to oxidation of contained iron minerals. It is opaque to translucent in thin sections. Its hardness is 1 to 2 in the Mohs scale. Its specific gravity is 2.8 to 2.9. Its luster is pearly to dull; it is recognized chiefly by its micaceous structure and cleavage, and its soft greasy feel. Two other varieties occur, one in which there are radiated needles in the crystalline form, and there is also a massive homogeneous structure found. Fine grinding reduces pyrophyllite to fiat plates or scales but aggregates of minute foliated plates may be formed.1 Distribution of Deposits Pyrophyllite is found in metamorphic rocks throughout the world but it is only in comparatively recent years that it has assumed much commercial importance. The principal

Jan 1, 1960