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By W. Rosotoker

Using an expression for the free energy of a homogeneous phase as a function of composition, a relationship is derived which interrelates the phase boundaries extending from the allotropic transformation of the solvent metal. Comparisons between observed and calculated phase boundaries in the systems Fe-Ni, Fe-Mn, Fe-W, Ti-Mo, and Ti-Cb are presented. IT is the purpose of this paper to illustrate how the general free energy equations for two phases in equilibrium may be used to derive an expression which interrelates the phase boundaries extending from the allotropic transformation of the solvent metal. The free energy per gram atom of a disordered solid solution may, for many purposes, be represented by the equation:' F = ½NZ [C-V,, + (1-C) VbB + 2C (l-C)V] + K(T) +RT[C-lnC+ (l-C)ln(l-C) ] [1] where N is Avogadro's number; Z, the coordination number; C, the concentration of the solute element in atomic percent; the subscripts refer to concentrations at phase mixture boundaries; VAA, VBB, and V,, are the bond energies between like and unlike adjacent atoms, respectively, at the interatomic spacing characteristic of the phase. The bond energies are usually assumed to be independent of small changes in the lattice parameter occasioned by solute additions and variations in temperature; V = VAB ---------------—— ; K(T) is the sum of the heat con- tent and heat entropy; R, the molar gas constant; and T, the temperature in degrees Kelvin. The free energy of a homogeneous phase is there- fore the sum of an internal energy, a specific heat, and a configurational entropy term, respectively. The compositions of two phases in equilibrium at a given temperature are governed by the minimum total free energy principle. Graphically, this is represented by the points of tangency of the tangent common to the free energy vs. concentration curves of the two phases. Analytically, this may be expressed as: ( df) = (df) [2] dc dc Expanding both sides using eq 1, the following equation is obtained after convenient readjustment of the terms: RT In[(ca)(1-c)]-½N (Vaa-Vbb)(Za-Zb) +NV [Za(l-2Ca)-Z,(l-2C,)] [3] The following assumptions have been made at this point: 1—The specific heats of the two phases are independent of composition variations within the range under consideration. Accordingly, the K(T) terms disappear on differentiation. 2— (Vaa)o = (VAA); (VBB). = (VBB); Va = V, Theyjustification for these assumptions can lie only in the successful application of the resultant equation. It may be noted that Zener2 has used assumption 1 in the calculation of the boundaries limiting the (a+j3) phase mixture in the Cu-Zn system.

Jan 1, 1952

By S. Froes

Official daily output of the Reconcavo (Bahia) oil fields, which amounted to 300 bbl., increased by the end of 1944 to 500 bbl. The new productive wells are in the district of Candeias. This figure is expected to further increase during 1945. The Itatig Company, which had drilled five wildcats in the state of Sergipe, stopped in 1944, but intends to resume work during the current year, or as soon as the war is over, in order to try the Cretaceous areas around its salt deposits. Several concessions applied for in the states of Sao Paulo, Parana arid Santa Catarina were favorably considered by the Conselho Nacional de Yetroleo, which is interested in fostering prospecting activities in the country. Several national groups are interested in exploring the federal gas field of Aratu (Bahia), a proposal having been made to use the gas in the manufacture of Portland cement. Undoubtedly the most important fact in the 1944 activities was the visit by two outstanding petroleum geologists, who had the opportunity to examine some of the principal areas and reported their opinions to the Brazilian Government. By special courtesy of the U. S. Government, Mr. E. DeGolyer spent a few weeks inspecting the gas and oil fields of the so-called "Reconcavo" of Bahia (a large tract surrounding All Saints Bay, on whose shore lies the city of Salvador) Later he exchanged ideas with Colonel Joao Carlos Barreto, President of the Conselho Nacional de Petrolco, as to the most adequate measures to develop production. Considering the oil problem in the southern part of Brazil, in the sedimentary belt including formations from the Devonian to the Triajsic, Mr. DeGolyer suggested a visit there by Mr. Lemis MacNaughton. The latter traveled during the months of June, July and August, accompanied by Brazilian geologists Avelino de Oliveira, Vice-president of the Conselho Nacionial de Pctroleo, Pedro Moura, Annibal Bastos, Burdot Dutra and J. Felicissimo, and verified the actual possibilities of the region, thus confirming the opinion of Pedro Moura, Avelino de Oliveira and Froes Abreu as to the advisability of thoroughly prospecting the south of Brazil. It is to be hoped that on the recommendation of these proficient American experts the Brazilian Government will take the necessary measurcs to carry out a complete search 01 such areas, which hitherto have been unsuccessfully drilled because knowledge of the structure was not adequate. The old Government policy of monopolistic essence has now given way to the more enlightened tendency of reconciling official action with private enterprise, which should in no way be curbed but rather encouraged. Such trend is heartily welcomed by financiers and technicians alike, who realize how indispensable is the cooperation of private capital, both national and foreign, in

Jan 1, 1945

By J. J. Kramer, W. A. Tiller, G. F. Bolling

THE axial orientations of columnar crystals in unidirectionally solidified ingots of zone-refined zinc and tin have been examined using the techniques recently described by us.' Both metals had an initial purity of 99.999+ pct before zone refining and satisfied all qualitative guides for very high purity after zone refining. Fig. 1 presents the orientations of the columnar crystals for tin and zinc, respectively. For tin, there is a preference for grains growing in the [I101 direction, i.e., the dendrite direction.' For zinc, a weak preference for the [0001] direction is seen (a random population in the unit triangle would give equal density on either side of the 60-deg circle centered on [0001]).' There was no apparent evidence for dendritic growth in either metal. These results, and those previously reported,' confirm the recent investigation by Hellawell and Herbert of casting textures observed for zone-refined lead, zinc, and tin.4 The preferred casting orientations for these metals in both the impure and zone-refined states are given in Table I. In the experiments on zone-refined lead,' it was shown that two separate textures existed: a preferred (111) nucleation texture existed at the chill surface and a preferred (111) texture developed during solidification. Either effect is sufficient to produce the result recorded in Table I. Similarly the results recorded for tin and zinc may be attributable to either a preferred nucleation or a preferred growth phenomenon and additional experiments are required to separate these two possible explanations. Hellawell and Herbert' attribute their results to a preferred growth process and account for it on the basis of a "layer-growth" model proposed much earlier by one of the present authors.5 An equally satisfactory growth model would be that based upon anisotropic surface energies. However, both of these growth models would indicate that the preferred growth direction for very pure metals should be normal to the plane of closest packing in the metal. This is consistent for zinc but, contrary to the conclusion of Hellawell and Herbert, it is not consistent for tin since here the (100) is expected to exhibit a greater density of packing than the (110). Although tin is expected to exhibit an anisotropy of thermal conductivity, we would expect the thermal conductivity to be the same in the [1101 as the [l00]

Jan 1, 1963

JAMES E. HOWARD,* Washington, D. C. (written discussion?). -Mr. Comstock, in his classification of the possible causes of transverse fissures, has not quite caught the point of view of the writer. It appears, following the trend of thought in Mr. Comstock's paper, that three groups instead of two might bee enumerated, namely: Fatigue of the steel, quality or, preferably, grade of steel, and mill practice. All steels are liable to failure by fatigue. Stresses that are capable of causing fatigue fractures are modified in their magnitude by the grade of steel acted upon. Mill practice is a term having a very wide meaning and in its relations to the development of transverse fissures has been used with such vagueness as to include many known factors and some that are unknown in the arts. According to the grade of steel employed, fatigue fractures may be accomplished by loads of greater or less magnitude, hence there is a relation between quality, or grade, of steel and the display of fatigue fractures. Mill practice of such an order as to affect the formation of transverse fissures must be shown to exert an influence on the ability of the steel to endure repeated stresses. Different grades of steel are selected for different purposes. Steel employed for fire-box purposes is of different grade from that used for cutting tools; although each grade is suitable for its purpose, and therefore of good quality. It is conceivable that a demand might be made for steel of physical properties in excess of those of any known grade. Under such a demand, impossible of' fulfillment, it would not be proper to refer to the steels as being deficient in quality; to do so would be a failure to recognize that all steels have their limitations in strength. Service conditions peculiar to rails admit of successive advance until the conditions can no longer-be met. The failure of a large number of rails from one type of failure, when all known means of averting the failure have been employed without success, is sufficient evidence that the end is close at hand. Iron rails, for a time, successfully met the requirements of railway service but weight of equipment, motive power, and rolling stock were increased, necessitating the use of steel. The early steel rails enjoyed the reputation of being of excellent quality, although: neither chemically nor structurally would they be so regarded ,lit the present time. They did good service in their day and under the conditions then prevailing were good rails. To meet the increased weight of rolling stock there has been

Jan 3, 1919

AS you and anyone else can understand, a great expense and a large supply of things are necessary for parting a quantity of silver by means of aqua fortis. First, as you have seen, it is necessary to have a great abundance of every kind of cucurbit and alembic, of charcoal and wood, and a large number of pounds of a vigorous, well-purified aqua fortis, because for every pound of silver there are of necessity [71v] at least four pounds or more employed from the parting to the coloring of the separated gold. It is also necessary to prove its fineness and to granulate or beat it, to have furnaces and supplies, and to provide for a thousand other necessities which need not be repeated now. The most important thing in this art seems to me to be that it requires continual working night and day with extreme watchfulness and care. For this reason another way, much quicker, less dangerous, and less expensive than the aforesaid one was found by some clever men (alchemists, I believe) in order to avoid such laborious and heavy methods. It produces the substance of the thing exactly as the acid does. If you wish to make use of it in conjunction with the acid it is possible to render great aid to this work although there is a great difference in the techniques of the two. The method used in this parting is as follows: First, make a round or square wind furnace for melting, below ground or above, and of height and size in proportion to the work and as it comes out best for you. Then take a large clay crucible and fill it almost up to the edge with that silver which contains the gold, cut into pieces, and put it to melt with the silver on top of a piece of brick cut to the size of the bottom of the crucible and resting on a grate in the middle of coals that are burning well. When you see that the silver has been made so hot by the fire that it looks white and that it wishes to begin to liquefy, take a little stick of sulphur or a small piece of antimony and put it in. When this is melted, lifting away the charcoal that covers it, put in more sulphur or antimony (for the method is the same with either one) until the silver is very well melted and these materials properly incorporated. Then for every pound of silver that you put in add half an ounce of sheet copper. When this is melted take your crucible out with tongs or pincers and strike the bottom gently on the coals two or three times so that the gold may make a residue on account of

Jan 1, 1942

By Thomas T. Read

MINING, which is at least twenty centuries old, was at first, and long, wholly a practical art. Little more than two centuries have elapsed since the inception of the idea that general education and a knowledge of natural science would be of advantage to those engaged in the mining industry. Though schools of mining began to develop in Europe early in the eighteenth century the concept of educational preparation for technical conduct of the industry was slow in winning general acceptance in the industry itself. John Hays Hammond, in his autobiography, recalls that when he sought employment with a mining company after he had graduated from Yale and Freiberg he had to assure its executive, before being even considered for employment, that he did not consider that he had learned anything about mining. This was as late as 1880. Existence in the industry of a prejudice against education of the academic type is perhaps an explanation why inadequate provision has been made by the mining industry for the continuing education of technical employees after they enter employment, although engineering education prior to engaging in industry has now won general acceptance. I am familiar with the existence of "loop" courses for engineering graduates in metallurgical plants, of schemes for giving mining graduates "practical experience," and of the interest in vocational courses for workmen which sprang up in the period of labor shortage during and immediately following World War I (but which quickly died when the depression of 1921 again made experienced workmen available in sufficient supply), having been chairman of a committee appointed by the Mineral Industry Education Division to make a survey of existing provisions for post-employment training for engineers in our industry. The results of that survey, reported elsewhere, dearly indicate that it is inadequate as to amount; the aim of this paper is to present evidence for belief that it is also inadequate in quality. To avoid becoming too involved, no reference will be made here to post-employment vocational training for workmen, which is a subject differing so much from post-employment education for engineers as to require separate treatment. Neither will postgraduate education for metallurgical engineers be discussed, because a distinction must then be made between training for research work and for plant operation, whereas mining engineers engage almost exclusively in operations. Since the situation in the coal-mining industry has been discussed at several recent meetings, that also will be passed over, and what follows should be taken as a discussion applying exclusively to the metal-mining industry. PROFESSIONAL DEVELOPMENT In the operations field (both in mining and metallurgy) the work to which a beginner is assigned is seldom closely related to previous academic- education. The contrast is almost as great as between

Jan 1, 1941

By Wayne E. Glenn

A centennial meeting should be a time to take stock, to evaluate performance, to plan ahead. It is like a line in a televised commercial that goes, "You've come a long way to get where you've got to today." And no less should be said of the mining and energy industries. We have come a long way. A hundred years ago when AIME was founded, this country produced 23 million tons of bituminous coal and 5.2 million bbl of oil. The figures in 1970 were about 580 million tons of coal and 4.1 billion bbl of oil. In spite of such accomplishments, serious and compelling voices are heard in the land - doubting sincerity, questioning corporate structures, and challenging ethics. Those doubts are raised in one part of Washington at the same time that other sections of the Capitol are asking us to produce more energy in order to keep up with population growth, emerging nations, and new technologies. Those of us in the fuel or energy business frequently talk about the race for energy. The question is, can we develop enough energy fast enough to outdistance our present and increasing demands? Recently I heard of an incident that - in an odd way - caused me to think of the energy race. The incident involved a sky-diver who jumped from an airplane without a parachute. He was handed a chute in mid-air by a sky-diving companion. He put it on, opened it, and landed safely. In a way, it seems to me that our society is hurtling through space and that it needs some help from the energy industries to land safely. We're doing our best, but under some rather difficult conditions. Because of illegal strikes and work stoppages the coal parachute is snarled a bit. The cut in percentage depletion and other tax changes have put some holes in the oil parachute. And the gas ´'chute has been in trouble for some time because of unrealistic controls on producer prices. The irony of the situation is that some of the very people who have been taking potshots at the energy parachutes for a long time are the ones who are complaining loudest now because the 'chutes are not functioning the way they could. The safety of the entire nation can depend on the energy industries.

Jan 1, 1971

By E. H. Crabtree

The heavy-media separation plant at the Central mill of the Eagle-Picher Mining and Smelting Co., near Picher, Okla., was started in February 1939. Since that time twenty-four million tons of lead-zinc ore has been treated in the mill, of which approximately 70 pct has been treated by heavy-media separation. Until January 1945, galena concentrate from the flotation plant was used as the sink-float medium. At that time minus 100-mesh ferrosilicon was substituted for the galena, and its use has been continued. The purpose of this paper is to compare the operating results and the costs of operation of the two media. For the purpose of this comparison the period Jan. I, 1943, to Jan. 29, 1945, has been taken to represent the operation using galena medium; the period Jan. 29, 1945, to Sept. I, 1946, to represent the ferrosilicon medium. During the first of these periods about seven and one-half million tons was milled; during the latter, or ferrosilicon period, more than five million tons was milled. It is believed that these tonnages are large enough to give representative data. Flowsheet The Central mill has a capacity of 15,000 tons per day. Briefly, the treatment used consists of crushing the ore through I½- in. and wet-screening out the minus 3/16-in. portion. The minus 136 plus 3/16-in. washed product is treated by the heavy medium; the minus 3/16-in. product is deslimed and jigged. The heavy-media cone tailing is discarded and the cone concentrate is recrushed and jigged for the production of a coarse lead concentrate. The cone concentrate, impoverished of lead, is then ground in ball mills and treated by differential flotation. The minus 3/16-in. jig product is similarly treated. Heavy-media Plant The heavy-media cone plant treating the minus I½ plus 3/16-in. product consists of one open-top cone 20 ft in diameter by 20 ft deep, equipped with a central airlift. Concentrate is discharged from the top of the airlift to a 3 by 14-ft low-head Allis-Chalmers drainage screen. Medium drains back into the cone, from the first half of this screen. The last half of the screen is provided with washing sprays for further removal of medium. Cone tailing is similarly drained and washed. Undersize from the washing screen is thickened and then cleaned in the medium-cleaning plant. When galena was used as a medium, cleaning was done in Fagergren and Denver flotation machines. The ferrosilicon is cleaned in three 36-in. and one 24-in. Crockett magnetic separators. A flowsheet of the cone plant is shown in Fig I.

Jan 1, 1949

By Thomas Clagett

THE Pocahontas coal field comprises the area in Tazewell County, Va., and Mercer and McDowell Counties, W. Va., in which Nos. 3 and 4 Pocahontas seams of bituminous coal are mined. It is a mountainous region with ridges rising 300 to 1000 ft. (91 to 305m.) above the very narrow valleys and, except for some poorly kept farms along the tops of the ridges and the area occupied by the mining and coking plants and villages, is wooded throughout. First shipments were made from Pocahontas in 1883. There are now, about 100 mines, 95 per cent. of which are drift mines. At the end of 1920, approximately 298,000,000 gross tons of coal had been produced and 35,000 acres of coal mined. No. 3 seam is from 4 to 10 ft. (1.2 to 3 m.) thick, but the change is gradual and the thickness fairly uniform in any particular locality. It has a streak of bone, about 2 in. (5 cm.) thick, io which the coal adheres on both sides. In parts of the field this bone is replaced by hard slate, usually from 2 to 4 in. thick. The seam has a slate or fireclay bottom and a draw-slate top. No. 4 seam is from 65 to 80 ft. (19.8 to 24 m.) above No. 3 seam, and of minable section only in the western part of the field. It is from 3 to 8 ft. thick and has two streaks off bone, each from 1 to 2 in. thick. It has a fireclay or slate bottom and is overlaid by from 4 to 24 in. of a laminated coal and slate, locally termed "black rash," which is separated from the coal seam by about 3 in. of slate. This "black rash" averages about 25 per cent. ash, but contains some clean coal. The coal in both seams is quite soft. Cleavage sufficiently well defined to exert an influence on the mining is rare. Overlying strata are slates, shales, and sandstones, the sandstones predominating, extending from .30 to 1000 ft. above No. 3 seam. The strata directly above the. draw slate of No. 3 seam, or "black rash" of No., 4 seam, and up to the first sandstone are usually slates or shales, about 10 ft. thick over the

Jan 5, 1922

By J. B. Umpleby

The function of gas in the development and production of oil has far-reaching consequences that should be emphasized. The technical aspects of the subject have recently had a great deal of attention but less thought has been given to fundamental concepts underlying oil and gas law and the many customs and practices that have grown up in the industry. I shall review briefly the advance in knowledge of the subject and attempt to relate these concepts to legislative, judicial and operating problems. Early writers on oil and gas in Pennsylvania noted their close association in oil pools and their contemporaneous decline in output; also, that as gas pressure decreases so does production, that new offset wells reduce the output of existing wells, and even that tubing a well lengthens its flowing life. Expanding gas was deduced as the principal expulsive force. These fundamental observations had been made at least as early as 1880.1 They were treated, however, as academic considerations and did not greatly influence law or practice for many years except to instill into all operators an urgent desire to hasten offset drilling in order to obtain as much of the flush as possible. The most noteworthy later advance in knowledge came in 1926 when Beecher and Parkhurst published their paper on Effects of Dissolved Gas upon the Viscosity and Surface Tension of OiL.² This paper added to the old idea of an expelling force the concept of a modifying agent that actually changes the physical characteristics of the oil and facilitates its movement through the pore spaces of the reservoir rock. Largely since the publication of this paper, intensive study and concerted effort have been given to means of using to a maximum, in producing oil, these combined properties of gas. This is shown clearly by the number of papers dealing with the subject, and the new and revived terms now widely used to express thought, such as the expressions gas energy, reservoir pressure, reservoir energy, gas-oil ratio, bottom-hole pressure, beaning, tapered tubing and back-pressure. These terms, some of which are

Jan 1, 1932

By T. A. Klinefelter, Glenn C. Truesdell, Richard W. Smith, R. G. Meara, O&apos

The investigation of domestic talcs was undertaken by the Bureau of Mines, Department of the Interior, in cooperation with the University of Alabama, at the request of the U. S. Army, on Dec. 1, 1941: "Considerable concern has been expressed by the Supply Arms and Service over maintaining continued availability of supplies of the necessary raw materials. These ceramic products are used by the Signal Corps in all army radio equipment, and to a greater degree in the new ultra-high-frequency equipment. The Air Corps has become a user of large amounts of radio-grade ceramics for' aircraft spark-plug covers required for high-altitude operations. In addition, the use of this material is essential to the proper functioning of the radio air-navigation aids of the Civil Aeronautics Board." History The use of steatite and talc in ceramic bodies goes back a great many years. If pure, talcs shrink little under heat-treatment and are very resistant to heat shock. The massive form, commonly called "steatite" by the trade, cuts and works easily, and this was naturally the first method used in obtaining articles of talc. When gas was in general use for illuminating purposes, a. large business was carried on in the manufacture of tips for gas burners.' With the development of uses for electricity, low-tension insulators were made in a similar manner; and, in fact, the forming of shapes from massive talc continues. However, as the business increased, cuttings and waste became more and more of a problem. In the twenties, one of the larger producing firms had a cooperative agreement with the Bureau of Mines at its Columbus station to work out a body using the finely powdered material. Somewhat earlier, manufacturers of spark plugs used the finely ground talc as part of the body and to some extent in wall-tile bodies. Somewhat later it came into use for kiln furniture and similar products and still more recently it has been used in some dinnerwares. With the development of the radio and the high-frequency fields generated, it was found that a dense steatite porcelain was far better than even high-tension electrical porcelain, which is a clay-flint-feldspathic type of body. Until the war increased the demand, the several pioneer steatite-porcelain manufacturers were able to furnish adequate supplies. When war began in Europe and Asia, three important foreign sources of raw material were cut off; i.e., the French, Italian, and Man-churian talcs. Domestic producers of high-grade porcelain are few, and the trade

Jan 1, 1948

By Edwin T. Myskowski, Alfred H. Hesse

THE development by the U. S. Bureau of Mines of a process for purifying manganese by electrolysis has stimulated interest in manganese alloys. While recent publications have shown some alloys of manganese and copper to possess rather unusual properties, none have included information on tensile properties, which have an important bearing on the usefulness of the alloys. Manganese-copper alloys can be heat-treated, since the single phases that exist at high temperatures may be retained by quenching. According to Persson,1 when quenched alloys containing from about 30 to nearly 100 per cent manganese are reheated, alpha manganese is precipitated (Fig. I). Calculations based on Persson's X-ray data indicate that this decomposition is accompanied by a change in volume of as much as 5 per cent. The reason that this large volume change has not been noted probably is the slow rate at which equilibrium is reached by these alloys. In an investigation on hardening by cold-work and heat-treatment, Dean and Anderson' found that quenched alloys increase in hardness with manganese content and that high-manganese alloys harden very slowly with cold-work, while high-copper alloys harden much more rapidly. Heat-treatment has little effect on manganese-copper alloys containing less than 40 per cent Mn, and affects those alloys containing more than 40 per cent in accordance with their manganese content and heat-treating temperature. Dean and Anderson4 also found that cold-work increased electrical resistance of alloys containing from 50 to 80 per cent Mn, and that heat-treatment of alloys containing from 40 to 96 per cent Mn altered the electrical resistance considerably. Dean, Anderson and Potter5 have shown that the high vibration damping capacity that characterizes manganese-copper alloys containing 40 to 90 per cent Mn is affected by cold-work and heat-treatments. Highest vibration damping capacity at low stresses was obtained by heating for 2 hr. at 450°C. (842°F.) after quenching from solution temperatures. Preparation of Alloys.-The alloys for these tests were melted in a 17-lb. basic-lined high-frequency induction furnace using electrolytic manganese, grade A ingot copper and a 70-30 Cu-Mn master alloy (69.80 per cent Cu, 0.12 Fe, 0.04 Si, 0.006 S, 0.07 C, balance Mn). The manganese was heated slowly to expel excess dissolved gases and melted before the addition of copper. No fluxes or covers were used. The melts were cast in tapered iron molds and the ingots were reduced 90 per cent when forged to ½ -in. rounds. These rods were given 2-hr. solution treatments at temperatures that depended upon the composition (Table I). Tensile Tests.-The tensile specimens, 0.313-in. diameter (1.25-in. gauge length), which were enclosed in evacuated Pyrex

Jan 1, 1942

The State Mining Bureau of California under the direction of Fletcher Hamilton, State Mineralogist, is starting a field campaign to report on the economic minerals of California, which have an important industrial and military bearing on the present war situation. Particular interest and value attaches at the present moment to our available supplies of chrome, coal, iron, magnesite, manganese, molybdenum, quicksilver and tungsten. Trained geologists and engineers of the Bureau's staff are being sent, out to obtain information with relation to the latest developments. Advance notices will be sent to the local newspapers, from time to time, of the arrival of the engineers in the various districts. All persons interested in the minerals mentioned are earnestly urged to cooperate with the State Mining Bureau by meeting the field men while in their districts or by communicating direct with the State Mineralogist at his office in the Ferry Building, San Francisco. The State Mining Bureau has just issued Bulletin No. 72 on The Geologic Formations of California. It was written by Prof. James Perrin Smith of Stanford University, and contains a complete bibliography and resume of all of our present knowledge relative to the geological formations occurring in California. It also contains much previously unpublished data, and six tables showing geologic columns. It covers 41 pages.

Jan 6, 1917

By J. R. Cahoon, W. V. Youdelis

In a recent publication by Flemings and Nereo, equations for the calculation of the solute distribution in castings were developed, and the solute distributions for unidirectionally solidified A1-4.5 pct Cu ingots cast under various thermal conditions were calculated. The equations derived by Flemings and Nereo for the dendrite "expansion" and "steady-state" zones are essentially equivalent to those previously published by Kirkaldy and Youdelis, 16 for, although the flow velocity cooling rate, and temperature gradients appear in the fundamental differential equations, calculation of the solute distribution requires that the above be explicitly related to the assumed or measured solid-liquid mass distributions during solidification. In the treatment of Kirkaldy and Y-oudelis the mass distributions are simply assumed or measured without any prior and explicit association of the mass distributions to a velocity parameter. The treatment of Flemings and Nereo permits solidification conditions more complicated than the simple unidirectional case to be considered (although in principle the treatment of Kirkaldy and Youdelis could also be extended to include the more general solidification case); however, we note some limitations in the treatment of Flemings and Nereo, and the purpose of this discussion is to point these out and also to indicate those points of similarity in the mass distribution models used which make the two treatments equivalent. Both the Kirkaldy-Youdelis and Flemings-Nereo treatments consider a zone of dendrite "expansion" followed by a "steady-state" zone. However, Flemings and Nereo have failed to consider a zone of "collapse" which begins at the base of the first dendrites to reach the top of the ingot. The omission of this zone of "collapse" results in too high a value for the solute concentration in the latter portion of the ingot to solidify and the conservation of total solute is not possible. In the zone of "collapse" the solute concentration rapidly decreases, which may be accounted for as follows: consider a mushy zone of length X,, shown schematically in Fig. 11 (a), which develops at the chill face and then moves as a steady-state configuration along the length of a solidifying ingot. The solute distribution in this zone, when it first attains the steady state, is shown qualitatively in Fig. 11(b). The segregation is positive (above Co) in the region ab because this region contains primary dendritic solid, ranging from kco to kcE in composition (where k is the partition coefficient and CE is the composition of the eutectic liquid), and liquid metal near eutectic composition. The segregation is negative (below Co) in the region bc because it contains primary dendritic solid only slightly above kco in average composition and liquid metal only slightly above Co in composition. As the zone X, moves as a steady state

Jan 1, 1969

By Arthur C. Simmons

Production of oil within the state of Pennsylvania in 1940 was slightly more than the 1939 total, and this increase was due entirely to the new flush Music Mountain field south and west of the main Bradford pool. The influence and magnitude of Music Mountain production will be separately described, inasmuch as it is an important producing unit within the state. Production Bradford Field The production listed herein for Bradford field includes only the part of the field that is within the state of Pennsylvania. Approximately 4000 bbl. per day, or 10 per cent of the total Production of Bradford field comes from Cattaraugus County, New York, and should properly be attributed to production obtained within the New York state area, although locally and economically the Bradford field, situated both in New York State and Pennsylvania, is included as a single statistical unit. The 1940 average production in the Bradford field was 34,831 bbl. per day, as compared with a daily average in 1939 of 35,340 bbl., or a decrease from 1939 of 509 bbl. per day. The decrease in production from the Pennsylvania portion of the Bradford field would have been more pronounced if a portion of the crude from the Music Mountain field were not included with the statistics for Bradford field. The decline can be attributed largely to the fact that more properties of lower average recovery were being drilled in 1939 and 1940 than in previous years, and apparently a subnormal amount of drilling occurred in 1938 and 1939, when about 2100 wells were drilled each year. The full effect of the 1940 drilling is not felt immediately and undoubtedly will affect the producing period of 1941. It appears probable that the water-flood area in the Bradford field has reached a definite peak unless some unusual economic condition should cause abnormal prices and an excessive rate of development such as occurred in 1936 and 1937. Virtually all of the production in the Bradford field was obtained by water-flooding methods, as natural or stripper wells are uneconomical and air and gas repressuring have not proved so efficient as water-flooding as a secondary recovery method. Central and Southern Pennsylvania Central and southern Pennsylvania produced a total of 4,604,763 bbl. of oil during the calendar year of 1940; that is, an increase over the 1939 total of 166,728 bbl. The daily average production was 12,581 bbl., or an increase over 1939 of 422 bbl. per day. Table I includes the total oil production for the state of Pennsylvania for the years 1937 to 1940, inclusive, and the daily average for each of these years. It is impractical to make a complete subdivision by districts, consequently the only segregation is the production from the Bradford field (within the state of Penn-

Jan 1, 1941

By William H. Spice

The fault zone of south central Texas showed renewed activity during I940 along a trend roughly paralleling the old established Balcones fault-line group of producing fields. This was a result of the new discoveries in the Wilcox (Eocene) formation in southeastern Texas and Louisiana. As of the end of the year, one new field producing from the Wilcox formation had been discovered on the Washburn ranch in La Salle County, along the southwestern limits of the district, and several projected tests into that formation were under way. In the western part of the district, par-titularly in the part of the Rio Grande embayment that is in Dimmit, Webb and Zavala Counties, there has been renewed leasing activity with the shallower sands in the Navarro-Taylor formations (Upper Cretaceous) as the objective in several projected tests for the early part of 1941. Three new fields have been discovered along the old fault-line trend, but these have been comparatively small, producing either from Dale lime, Austin chalk or Buda lime. No new fields were discovered during the Year in the Edwards (Lower Cretaceous) lime horizon. Approximately 260 wells were drilled in the district during 1940, which resulted in four new oil fields. Twenty-seven new wells were completed in the Proven Edwards lime fields of Darst Creek, Luling and Salt Flat and seven were added to production in the Pearsall field. Approximately 160 wells in 18 counties were completed as failures during the year. The district produced 7,659,634 bbl. during 1940, which was a 9 per cent decrease under production for 1939. In all, 3559 wells were producing at the end of I940, compared with 3562 wells producing at the end of the previous year; 104 new producing wells were completed and 163 wells were abandoned in the producing fields of the district. During 1940 considerable exploratory work was carried on along the Wilcox trend within the district, particularly by major companies employing various types of geophysical methods, and leasing activity increased considerably. At the end of the year, the total number of acres of nonproducing leases held by major companies in the district increased about 10 per cent. It is anticipated that this activity will continue into the first part of 1941 and will be supplemented by several exploratory test wells. New Fields B,, Creek, Caldwett County.— . R. Ogden NO. 2 Talley, discovery well of the Bee Creek field, in the northeastern part of Caldwell County, was completed on March 16, I940, in Dale lime from 2091 to 2238 ft., pumping 85 bbl. per day, 39° A.P.1. gravity. The discovery of this field can be credited to a combination of subsurface geology and magnetometer work, which indicated the presence of a serpentine intrusion. At the end of the year, ,3 producing oil wells had been completed and the field has produced a total of 47,050 barrels.

Jan 1, 1941

R,. P. JaRvis,* El Oro, Estado de México, México.—The practical problem raised by Mr. Wisser—that is, the determination of the lower limit of ore deposition, below which it is useless to look for ore shoots—is one of the most important in economic geology. He asks: "Can we learn to determine the position of such a line?" For individual districts, yes; but its determination has always been by empirical methods; that is by actually exploring the veins to such depths that the values drop below the economic limits. Usually the signs are plain enough that values have been bottomed without confirmation by the chemist or assayer. Most veins, when approaching their limit, begin to split into branches or stringers; the vein matter itself undergoes a change from "lively looking" rock to one that is dull and unpromising, the quartz, instead of having segregated into clean vein matter, has simply spread itself into the country rock, rendering this more siliceous but no richer—these, together with inclusions of the country rock in the vein, are all positive indications of the limit. Mr. Wisser seems disposed not to accept the law of cause and effect, which he calls "empiricism." He says: "Empiricism embodies an assumption perhaps not evident at first glance. It is this: that like effects spring from like causes and therefore necessarily have a common meaning." There can be no doubt as to the validity of this law, since it is the foundation stone upon which are built all inductive sciences, including economic geology. When demonstrable, proved facts become confused with inferences, as they seem to be generally in the paper under examination, no sound conclusions can be reached. Mr. Wisser has failed to give sufficient data covering the two vein systems which he cites as examples. Presumably they are situated in the Pachuca District of Mexico, but not everybody is familiar with the vein systems there in spite of the fact that it is world famous as a silver producer. Are these two systems separated some distance horizontally from one another and how far? He has given no estimate of the amount and kind of rock that has been eroded from over the present veins. His description of the two systems appears on page 100, beginning: "1. East-west veins," and ends on page 101, "they would lack spaces there in which to deposit." On page 101, with the paragraph beginning "On the other hand," he gives a picture of what he believes takes place in class 2 veins. The sum of this seems to be, according to Mr. Wisser's observations, that, in the east-west veins, class 1, there has been an invasion of an "altering solution," which I judge has been responsible for the formation of extensive "alteration haloes"; that these alteration solutions have followed along pre-existing fractures or fissures; and that after these alteration solutions finished their work the mineralizing solutions deposited the vein matter and metallic values. Mr. Wisser does not specify clearly what the "alteration haloes" consist of; in other words, what change the original rock has suffered, whether oxidizing, carbonating, or sulphidizing. If they came from depth they could not be oxidizing or carbonating, and in this case it is a bit

Jan 1, 1941

By J. H. Slater

There is nothing particularly new about the use of sinter in a blast-furnace burden. For many years flue dust has been sintered at the various blast-furnace plants to put it in a form that could be recharged to the furnace with some assurance that it would stay in the second time. This paper is not a compilation of scientific data but only an attempt to give our experience with sinter. There are some unexplained discrepancies in the tests given here, such as the flue dust produced and iron tonnages, but the results given are the results that were obtained. Sinter is not the cure-all for blast-furnace problems. A good coke is still the most important factor in good furnace operation. However, good sinter is a big help. As flue dust is produced under varying operating conditions and fluctuates greatly in carbon content, it is difficult to produce from flue dust alone a uniform sinter, which will give satisfactory blast-furnace results. Sinter made from flue dust alone will change in character with every carbon variation. Almost invariably flue dust contains carbon in excess of the amount necessary to make good sinter, and this excess must be burned out. This, of course, necessitates reduction of the speed of the sintering machine and thus a decrease in tonnage. An alternative is to dilute with a carbon-free material to use up the excess carbon. High-carbon material when sintered results in a very dense, undesirable product, since the excess heat melts the charge into a hard, nonporous mass, and tends to form refractory silicates. At the Republic Steel plant in Cleveland, there had existed since 1924 a continuous-type sintering machine having 224 sq. in. of grate-bar area, capable of producing 9 to 11 tons of sinter per hour from flue dust. Under a former management, it was the practice to sinter only the flue dust from the blast furnaces, no attempt being made to recover the gas-washer sludge. As the dust was limited, the plant operated only part time. In other words, there was a sintering plant representing considerable investment, with good facilities for screening and preparation of raw materials, and flue dust available for only part-time operation. The sinter produced was costly and not a very desirable product. The first step was to install equipment for the recovery of the gas-washer sludge. This was done in the form of two large thickeners and a filter, which have proved very satisfactory. It was then decided to screen out the minus 3/8-in. fines from the Mesabi ores, mix them with flue dust and coke breeze when necessary, and operate the plant at full capacity. The tonnage increased to 18 tons per hour and the product was much improved. Sintering costs fell and the product was a preferred blast-furnace material, which on an iron unit cost compared very favorably with good Mesabi ores. On the average, 40 per cent flue dust and 60 per cent fine ore was being used. The oversize from the ore screening also became a preferred product for the

Jan 1, 1941

By G. G. Gunther, C. L. Boeke

DISCUSSION I. M. Symonds, (Cia. Minera de Penoles, Monterrey, N. L., Mexico)—Messrs. Boeke and Gunther have written most interesting papers describing their zinc de-leading operations. Mr. Gunther was kind enough to show me his operation last fall. Aside from the excellent results, I was most impressed by the ease of control. I had expected a difficult operation requiring careful control and supervision, but found one requiring little attention. The only disappointing fact of the separation is the poor copper recovery in the concentrate of the delead-ing float. The final zinc concentrate still has about 3 pct chalcopyrite, assuming the copper is chalcopyrite, and adversely affects the zinc grade. If the copper mineral is free, the poor recovery is probably due to the high cyanide concentration. Fortunately, about 75 pct of the copper is recovered before the pulp goes to the zinc circuit. Mr. Gunther's remarks about proper cyanide to zinc sulphate ratios cannot be overemphasized. Although our experience has been confined mostly to the conventional lead-zinc separation, we have found these ratios most important, and more important in the mill than in the laboratory. The laboratory appears to give optimum results over a wider range of reagent control than the mill, especially in regard to the effect of cyanide. In handling relatively high grade ores in the mill we usually find that ratios of cyanide to zinc sulphate of 1 to 10 or 20 or higher work best. Where there is a substantial amount of chalcopyrite present it has been noted that cyanide in the range of 0.02 to 0.10 lb per ton of ore is often beneficial in zinc rejection and possibly in copper recovery in the lead concentrate, while larger amounts, say 0.20 to 0.25 lb per ton, will float more zinc and cause a serious rejection of chalcopyrite. On an ore with 15 to 20 pct zinc content we have had to use 0.8 to 1.2 pounds of zinc sulphate per ton of ore with the above cyanide to obtain optimum results. Some time ago we made a laboratory study following Parral and Santa Barbara practice on an ore which had never a very satisfactory rejection of zinc in the lead concentrate. The results were not encouraging and a mill test was not run. Since then the study has been reopened using in the laboratory fresh zinc concentrate from the mill instead of one made in the laboratory. A reasonably clean lead float from the zinc concentrate was obtained. It has been checked several times and each time the zinc concentrate made in the mill responds and the one made in the labora-

Jan 1, 1953

By Basil B. Zavoico

The symposium on production for the year 1942 contains no papers on the foreign situation except those on Argentina and Mexico. It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts From Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not determinable from data available to the author, please insert y; in spaces where the proper entries are determinable by the author, make such entries. y implies a Rope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and it is an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when subtracted, should give the approximate thickness of the productive zone. For fields where this is not true because of unusually high dip or for some other reasons, it is suggested that the authors indicate in their text the approximate average thickness of the productive zone.

Jan 1, 1943