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By T. B. Counselman

"C" VERYONE who has to calculate cyanide circuits, -¦-' using either thickeners, filters or both, realizes the headaches involved in solving a set of simultaneous equations. When you calculate a large number of these, based on experimental data, trying to arrive at the best flowsheet, you can spend days at the task. T. B. COUNSELMAN, Member AIME, is Manager, FluoSolids Division, The Dorr CO., Stamford, Conn. AIME New York Meeting, Feb. 1950. TP 2783 B. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Manuscript received Aug. 23, 1949. Herewith is presented a short method, equally accurate with the standard simultaneous equation method, and much quicker. Here for instance is the standard simultaneous equation method, for 100 tons per day of $10 ore, with the conditions assumed as below (fig. 1). Conditions Assumed a. 100 tons of ore per day crushed in cyanide solution. b. Discharge from all thickeners with 50 pct moisture. c. $10 value dissolved per ton of ore. d. 50 pct in mill and 50 pct in agitators. e. 400 tons of solution from thickener V precipitated to $0.02. f. Agitation with a dilution of 2 of solution to 1 of solids. g. Let V, W, X, Y and Z represent value in dollars per ton of solution discharged from the resvective thickeners. Equating Out of and Into Each Thickener 1. lOOVplus 400V = 500W plus (0.50 X $10 X 100) 2. 1OOWplus 600W= 500X plus lOOW plus (0.50 X $10 X 100) plus lOOV 3. lOOXplus 500X = 1OOWplus 500Y 4. 1OOY plus 500Y = 1002 plus 1OOX plus (400 X 0.02) 5. 100 Zplus l00Z = l00Y plus 100 tons of water (value $0.00) Simplifying: 1. v = W plus 1.00 2. W = X plus 1.20 3. X = Y plus 0.24 4. Y = 0.2Zvlus 0.064 5. 2Z= Y

Jan 1, 1951

By W. H. Andrews

THE constantly increasing consumption of Portland cement in the State makes the above subject of partlcular interest at this time. The increasing demand is due to the rapid settling of the country and the fact that new uses are being found frequently for the above named commercial article. The industry is one that is bound to grow as the population increases, and this being the case, it may be well ,it this time to consider briefly- the matter of the chemical and physical com-position of proper raw materials. A cement mixture is one that contains approximately 75 per cent. carbonate of lime, 15 per cent. Silica, and 5 to 7 per cent. alumina, and iron oxides; the other elements being magnesium carbonate and small quantities of the rarer elements general associated with limestone deposits. It call be readily seen from the above composition that it is possible to build up this mixture from a number of different materials. First.-A rock high in carbonate of lime can be mixed with clay or shale in such proportions as to bring about the desired composition ; the chief difficulty in the building up of such a mixture is that it is hard to find a clay or shale in which the silica-alumina, ratio lies .between 4 to 1 and 3 to 1 and at the same time shows physical characteristics which will make certain its adaptability to the practical manufacture of Portland cement. Very often clays or shales are found which are right chemically but contain large quantities of grit or free silica. Such clays or shale must be ground to extreme fineness in the mixture in order to make the silica and alumina combine with the lime when the mixture is burned. On the other hand, clays or shales are often found that have the proper physical characteristics but in which the amount of alumina, is too great.

Jan 9, 1913

By R. E. Cook

This paper presents results of a study to determine to what extent errors in estimated free gas saturation affect the results of static pressure calculations from build-up curves in two-phase systems. Use is made of the method of pressure build-up curve analysis developed by Miller, Dyes and Hutchinson1 , with modifications for two-phase flow advanced by Perrine2. Cornhined fluid compressibility of gas-oil mixtures is included, with special attention given to the discontinuity that occurs in fluid compressibility at the saturation pressure and its effect on static pressure calculations from build-up curves. The sensitivity of static pressure calculations to errors in gas saturation is considered over wide ranges of formation and fluid properties and reservoir pressure conditions. It is concluded from this study that for analyses of two-phase pressure build-up curves (I) the use of under-saturated crude compressibility data, even when producing GOR's are at or near solution values, will result in very significant negative errors in calculated static pressrrre, and (2) except for large values of buildup curve .slope and/or very low crude gravities, rather large errors in calculated gas saturation can he tolerated without .significant effect on calculated static pressures. The conc1usions arc qualified as referring only to the effects of gas saturation and excludc possible errors in the nuumerous other factors that enter into the ancllysis of pressure build-up curves. INTRODUCTION As part of the analysis of basic data for several major Eocene reservoirs in the Bolivar Coastal field (Western Venezuela), it was necessary to analyze a large number of pressure build-up curves for oil permeability and static reservoir pressure. From performance data it became apparent that gravity segregation is very active in these reservoirs. As a result of this performance it was recognized that the free gas saturation within the oil leg of the reservoirs would be small but would be subject to certain errors in calculation due to the inaccuracy of relative permeability data in the low gas saturation region. Since all of the various methods of build-up curve analysis were originally derived for sin- gle-phase, constant compressibility systems, and since the presence of a small but rather indeterminate gas saturation would greatly affect the reservoir fluid compressibility, a study was undertaken to investigate the effect of gas saturation on the results of two-phase pressure build-up analyses. TWO-PHASE BUILD-UP CURVE ANALYSIS The method of analysis used in this investigation is basically that originally developed by Miller, Dyes and Hutchinson1, with modifications for two-phase flow advanced by Perrine2. Miller, et al, showed that the original equation for single-phase permeability away from the well bore, held for two-phase flow except that the calculated permeability is the effective permeability to oil away from the wellbore. This finding was acknowledged by Per-rine, who also presented the equation for effective gas permeability* as Since Eqs. 1 and 2 contain no terms influenced by fluid compressibility, no distinct problem should develop in calculating permeability from two-phase build-up curves. In regard to the calculation of static reservoir pressure from build-up curves in single-phase systems, the modified Miller, et al, method as presented by Perrine is briefly as follows. 1. From build-up curve data, PVT data for the reservoir fluid and the well spacing and sand thickness, calculate the climensionless shut-in time corresponding to the highest value of actual shut-in time (t, hrs) on the straight-line portion of a semi-log build-up curve. Dimenrsionless shut-in time is related to actual shut-in time by the relation, t- 0.000264 kt 2. From a graph of dimension less shut-in time vs dimensionless pressure difference (Fig. 1 1 ) find the value of dimensionless pressure difference corresponding to the value of 7 calculated under (1) above. Dimen-

By J. Bruce Wagner, Roger L. Levin

Integrated forms of two solutions of Fick's second law for the movement of a plane interface through a sample of wustite, and for diffusion into a semi-infinite slab of wustite, are shown to yield nearly identical values of the chemical diffusion coeffcients of cation vacancies in wustite, over the temperature range 900° to 1100°C. The chemical diffusion coefficients, the values of D obtained for the propagation of a concentration gradient through samples of undoped and doped wustite, are obtained from the equations It is becoming increasingly important in metallurgical practices to understand the role of the chemical diffusion coefficient, i.e., the diffusion coefficient of a species across a concentration gradient. During the first stages of sintering, one of the mechanisms by which the bonds between neighboring particles develop is by volume or bulk diffusion. This diffusion coefficient as deter- where ?m is the weight change at any time t, ?W is the total weight change at t =8, A is the area of the specimen, and AC is the total change in the cation concentration after the establishment of equilibrium, as determined by reduction experiments in different carbon monoxide -carbon dioxide mixtures within the limits of existence of the single-phase field. mined from the standard equations for volume diffusion during sintering is actually a chemical diffusion coefficient, and it has been observed to be many times larger than the self-diffusion coefficient as determined on the same materials by experiments using radioactive tracer techniques. Kuczyn-ski1 has noted that, if the controlling mechanism of sintering of A12O3 in an oxidizing atmosphere is the diffusion of oxygen, then this diffusion coefficient as measured from sintering rates is about 2.2 x 104 higher than the self-diffusion measurements obtained by tracer techniques. He has also reported the diffusion coefficient obtained from the rate of sintering of Fe2O3 powder to be about 10 6 times faster than the self-diffusion coefficient of

Jan 1, 1965

Boiler-Room Economy "Establishing and Maintaining Boiler-room Economy" is the title of a paper presented before the Ohio Society of Mechanical Electrical and Steam Engineers by Geo. H. Gibson, of which the following is an excerpt: Boiler-room economy depends less upon equipment than upon operation, i.e., it depends largely upon the condition in which the apparatus is maintained and how it is used. A given boiler may operate this week with an efficiency of 78 per cent., and next week with an efficiency of 65 per cent., while using the same fuel and developing the same rating. If there are variations ii; character of fuel and in load and other factors, the falling-off may be even greater, possibly to less than 60 per cent. The steam produced may cost twice as much per 1,000 lb. at one time as at another. Most steam plant managers know from their own experience that these statements are not exaggerated. It does not take much of a plant to run up a coal bill of $5,000 per year, many "spend $10,000 for coal, and fuel bills of $50,000, $100,000, or $200,000 per annum are not uncommon. As it call be shown in the majority of these plants that 10 per cent. of this amount may be saved, and in large numbers of them 25 per cent., while in some the expenditure can be cut in half, there is no disputing that we have here a subject worthy of attention. In the production of steam the greatest variable is the human factor. Before we can pass judgment, however, we must first have standards. This implies accurate quantitative knowledge of fuel consumption and steam production. We must measure the output and know how much the steam costs per thousand pounds, and how many pounds of steam are obtained from a pound of coal. We can then begin to analyze the problem, and find where and how methods and conditions can be improved, and how much. Many favor buying coal on a B. t. u. basis. This is advisable where the amount purchased warrants the considerable expense involved in systematically gathering samples that: are. truly representative and in having analyses made, of every carload. Coal analyses, combined with. an honest endeavor on the part of the miner to ship good coal, should insure the receipt of the heat units paid for. , It often happens, however, that the coal which is cheapest on a B.t.u. basis is not the cheapest or most suitable for producing steam, because of peculiarities of the plant in which it is to be burned, or conversely, the fuel which furnishes cheap B.t.u. may require special methods or equipment for its economic utilization.

Jan 2, 1916

By M. C. Flemings, A. A. Tzavaras

Analytical and experimental procedures are descrihed for quantitative determination of volume-fraction microporosity in metals by mimorarlio-graphg. The analysis assumes spherical pores but allows for the observed fact that pores or portions of pores smaller than a given thickness do not project an image on the film. Volume-fraction microporosity was measuured in cast low-alloy steel and shown to vary from 0.6 x 10-4 to 10 x 10 depending on mode of solidification and on whether the material was air- or vacuum-cast. The aim of work described herein was to develop a method of quantitative measurement of the volume fraction of microporosity in cast metals. Microporosity, present in nearly all castings and ingots, is always interdendritic in nature and may be large enough to be seen on a polished surface with the naked eye. More generally, it is smaller in size, and its detection more difficult. Three techniques might be considered for measurement of microporosity: 1) lineal analysis of a polished metallographic surface, 2) density measurement, or 3) quantitative microradiography. As will be shown later, volume fractions of porosity in directionally solidified castings may be the order of 10-4 to 10-3; such small amounts of porosity are difficult to identify and measure on a polished surface. Density measurement is also not a suitable technique (for alloys) when the volume fraction of porosity is low. This is because the density of the base metal is often not known within the necessary accuracy, due to microsegregation or partial phase transformations. In general, it is not possible to completely eliminate microsegregation without also altering the porosity. Because of the limitations of the foregoing techniques, quantitative microradiography was employed to determine amount of porosity. In recent work, microradiography has been found to be useful for qualitative measurement of porosity, including determination of size and shape of individual pores;&apos;)&apos; however, quantitative determination of amount of porosity has not been attempted. I) CALCULATION OF VOLUME-FRACTION POROSITY The following analysis employs procedures similar to those of Cahn and Nutting3 and Hilliard.4 Major simplifications are that pores are assumed to be spherical and to be present in sufficiently small quantities that no overlapping occurs. A basic difference from the previous treatments is that the limited "sensitivity" of microradiography is considered. Assume first 1) cavities are spherical and of uniform diameter, 2) cavities are randomly distributed, 3) volume-fraction porosity and specimen thickness to pore radius ratio are sufficiently small that overlapping of the projected images of cavities is negligible, 4) sensitivity is limited (i.e., holes or portions of holes of less than a given thickness do not project an image on the film). The sensitivity, is defined as: where 5 = minimum thickness of void from which an image will be projected on the film and t = specimen thickness. Now, from Fig. 1, it is possible to distinguish between two different types of holes. These are 1) holes whose centers lie within the region t/2 > X > 6/2, where X is distance from one surface of the specimen (positive into the specimen), and 2) holes whose centers lie within the region (6 — r) < X < 6/2, Holes whose centers lie outside X = (6 -r) project no image on the film. These two types of pores are considered separately below. Type 1 Pores. When 6 is greater than 0, the image of a spherical cavity of radius r appears on the film as a circle of radius a which is smaller than r. From geometry, Fig. 1: a2=r2-52/4 [2] where a = radius of image of pore on film and r = radius of pore. Since the pores are randomly distributed and spherical V =4/3pr2Nv [3] where V = volume fraction of voids and Nv = number of pores per unit volume and the number of images of Type 1 pores per unit area of film, N&apos;A, is

Jan 1, 1965

By C. W. Spencer, J. Singer

A PARTIAL phase diagram for the As-Te system is given in Hansen.&apos; The only compound reported is As2Te3, melting at 362°C. Stoichiometric quantities of reagent-grade elements were reacted in evacuated quartz and directionally cooled. The resulting ingot consisted of very thin threadlike crystals from which only very small single-crystal fragments were isolated. A powder diffraction diagram disclosed nonisomorphism with the analogous V-VI compounds insofar as these have been reported; Sb2S3, As2S3, Bi,S,, and Bi2Te3 data in the ASTM index of powder patterns, together with the single-crystal data on Sb2Se3,2 were used for the com- parison with the observed spacings. Single-crystal data confirmed the uniqueness of the As2Te3 structure. Single-crystal Weissenberg diagrams have so far yielded the following data: As2Te3 is monoclinic, space group C-m (OkO data still lacking), a = 14.4A, b = 4.05A, C = 9.92A, ß = 97". The cell volume is about 5802. The set of isomorphous ortho-rhombic cells of Sb2Se3, Sb2S3, and Bi2S, are apparently related to As,Te, in having one lattice constant close to 4.0 and with cell volumes as large as 540A8. Assuming Z = 4 for As2Te3 also, the density is calculated as 6.1 which agrees well with a roughly determined value of 6.0. A complete structure analysis is under way.

Jan 1, 1956

By D. A. Crerar, R. L. P. Kleinmann, R. R. Pacelli

A bacterium, Thiobacillus ferrooxidans, is of prime importance in the formation of acid drainage from pyritic material. Above pH 4.5, T. ferrooxidans increases initial acidification; below pH 4.5, it allows acidification to continue by oxidizing Fe2 +. Below a pH of approximately 2.5, the activity of F3+ is significant and results in steady-state cycling between oxidation of pyrite by Fe3 + and bacterial oxidation of Fe2 +. Laboratory and field tests demonstrate that inhibition of T. ferrooxidans by controlled release of anionic detergents can inexpensively reduce pyrite oxidation and acid formation.

Jan 1, 1982

By AIME AIME

The following report is published for the information of the members: Meetings. Two meetings for the reading and discussion of papers, etc., have been held during the year 1907-namely, the Ninety-second meeting, held April 16 to 20 in New York, N. Y., and the Ninety-third meeting, held July 23 to 30 in Toronto, Canada. The proceedings of these meetings, including descriptions of the entertainments and excursions connected therewith, have already been published and distributed to the members of the Institute; the New York meeting in Bi-Monthly Bulletin, No. 15, May, 1907, pp. 541 to 559, and the Toronto meeting in Bi-Monthly Bulletin., No. 17, September, 1907, pp. 847 to 875. In addition to these " Proceedings," there were also published in Bi-Monthly Bulletin, No. 15, May, 1907, an illustrated description of the United Engineering Society building (p1 vi. to xxvi.), and a record of the exercises attending its dedication, including the addresses of Andrew Carnegie, Arthur T. Hadley, Samuel Sheldon, Frederick R. Hutton, John Hays Hammond, and T. C. Martin (pp. xxxviii. to lxv.). At the New York meeting, 43 papers and- discussions were presented, and the names of 297 members and guests were registered at the Institute headquarters., this number, however, does not represent all who were present at the sessions and excursions. At the Toronto meeting, 23 papers and discussions were presented. The number of members and guests registered at the Toronto headquarters was 191, which doubtless does not include the names of all who were present at the sessions, or took part in the numerous excursions and visits around Cobalt.

Mar 1, 1908

By Charles Maier

IT has long been supposed that when crystalline materials are com-minuted the energy used in the production of increasingly smaller grain sizes is not entirely dissipated as heat but that a certain portion is "stored" as a part of the internal energy of the material. This portion usually has been called the "surface energy" of the particles. The practical interest of the Bureau of Mines in this subject in connection with the energy requirements of crushing processes has led to the author&apos;s attempt to measure the "stored" energy in finely divided calcite by heat-of-solution methods1. The experiments on calcite showed that "storage" of energy could not be proved for this material, because fine grinding caused a lack of chem-ical homogeneity evidenced by loss of carbon dioxide and subsequent adsorption of water on the surfaces of the calcite particles. When thermochemical correction was made for composition changes the cor-rected heat of solution was less for fine material than for coarse. Con-tinuation of the experimental work into the problem of comparing work and heat in the deformation of metallic crystals, where the calorimetric difficulties were less, showed, however, that in the case of copper and aluminum a real discrepancy between work and heat could be shown. similar results had previously been obtained by Farren and Taylor2 and Hort3 and more or less simultaneously with the author&apos;s work by

Jan 1, 1936

By Charles Maier

PART I DENSITY AND ENERGY CHANGES IN COLD-WORKED COPPER IT has long been supposed that when crystalline materials are com-minuted the energy used in the production of increasingly smaller grain sizes is not entirely dissipated as heat but that a certain portion is "stored" as a part of the internal energy of the material. This portion usually has been called the "surface energy" of the particles. The practical interest of the Bureau of Mines in this subject in connection with the energy requirements of crushing processes has led&apos; to the author&apos;s attempt to measure the "stored" energy in finely divided calcite by heat-of-solution methods1. The experiments on calcite showed that "storage" of energy could not be proved for this material, because fine grinding caused a lack of chem-ical homogeneity evidenced by loss of carbon dioxide and subsequent adsorption of water on the surfaces of the calcite particles. When thermochemical correction was made for composition changes the cor-rected heat of solution was less for fine material than for coarse. Con-tinuation of the experimental work into the problem of comparing work and heat in the deformation of metallic crystals, where the calorimetric difficulties were less, showed, however, that in the case of copper and aluminum a real discrepancy between work and heat could be shown. Similar results had previously been obtained by Farren and Taylor2 and Hort3 and more or less simultaneously with the author&apos;s work by

Jan 1, 1936

By C. Z. Serpan, L. J. Wittenberg

The density of liquid plutonium was determined, by a pycnometm&apos;c technique, from 664 to 788°C and exhibited a temperature dependence, which could be expressed as:. P= C17.63 - 1.52 x 10-"t] +0.04 g per cc where t = OC. These density values compare favorably with the values previously obtained by a technique utilizing Archimedes&apos; principle. The apparatus and method were evaluated when the densities 0.f molten tin and bismuth were measured and found to be in agreement with accepted literature values. PLUTONIUM or an alloy of plutonium in the liquid state has been proposed as a fuel for a fast-breeder type nuclear power plant.&apos; Since knowledge of the liquid density of plutonium is required for the proper design of such a system, this study was undertaken. In addition, the density and volume expansion coefficient of liquid plutonium are of interest for comparison with these same properties of the six allotropic modifications of the solid metal. Comstock and GibneyZ were first to report a value for the density of liquid plutonium. The value for only one temperature, 665"C, was calculated from data obtained by the radiography of the meniscus, Fig. 3. Recently, the density at a series of temperatures has been reported by Knight,3 who obtained his values by using a differential volumeter, and by 01-sen, Sandenaw, and Herrik, who obtained their values from measurements of the loss in weight of a tungsten bob immersed in the liquid. The density of liquid plutonium reported here was determined by a vacuum pycnometer method. In an evacuated system, the tips of calibrated tantalum pycnometers were lowered beneath the liquid sur-

Jan 1, 1962

By Clifford C. Hanninen, Allan H. Caverson

Within the past nine years a means for measuring the distance between mine roof and floor was developed at the White Pine mine which yields relevant information utilized in the mining operation. The technique known as "convergence" is an efficient, low cost way for obtaining large quantities of data for predicting roof falls, caving activity and overall mine stability. Since 1964 the activity of convergence measurements has expanded to become a production tool found in all sections of the mine. The program involves four types of activity: 1) monthly measurements in areas known to be active and in sample blocks scattered throughout the mine for a long-term stability study; 2) semi- monthly measurements along vital travel roads, belt drifts and compressor sites; 3) weekly measurements in areas where men are working; 4) daily measurements in pillar-recovery and caving operations.

Jan 5, 1973

By American Institute of Mining Engineers

David J. Mack (University of Wisconsin, Madison, Wise.)—Have the authors considered that the effects reported in their paper are readily explainable on the basis of equilibrium grain boundary segregation rather than ordering? It seems to the writer that all of their experiments and observations correlate well with known behavior associated with equilibrium grain boundary segregation. Although at first glance one would tend to dismiss such a possibility because of the similarity of the gold and copper atoms, their sizes differ by 12.8 pct which is in the range where segregation at grain boundaries would be expected. Then, too, the electrochemical differences between the copper, the Cu3Au, and the gold strongly suggest that a segregation mechanism is involved in the corrosion of the Cu-Au alloys. R. Bakish and W. D. Robertson (authors&apos; reply)—The authors would like to thank Dr. Mack for his consideration of the problem of grain boundary segregation as an explanation of the observed phenomena. We had considered the problem in the following terms: Assuming a pure binary Cu-Au alloy and an ideal solid solution, the surface excess, T2= N25 — N2, of the second component (gold) may be expressed in the following way20 1 —exp (—da/kT) where 8 is the difference in surface tension of copper and gold, and a is the surface area per atom. In the present case, 6 is positive which implies that the component in excess at the boundary is gold. Since the only chemically active component in ferric chloride is copper, it does not appear that the segregation of gold is likely to increase the boundary activity. A small concentration of a third component could profoundly affect the situation. Analysis indicated only spectrographic traces of impurities, all of which are soluble in both copper and gold. Quenching experiments, reported in the paper, also tended to eliminate significant effects attributable to a third component.

Jan 1, 1958

By Walter J. Karplus, Otto J. M. Smith

The transient response of earth formations may be tlcter.171ined by means of four electrodes mounted coli-rienrly on n sonde. Exponentially decaying current pules are applied to one pair of electrodes and the re.rrrlting voltage transient at the other pair is recorded. It is shown by theoreticol analysis and verified by laboratory experiments that this arrangement readily yields the direct resistivity of the formation and provides valrrable additional information as well. INTRODUCTION Although electrical transients have been employed with moderate success in geophysical prospecting, their application to well logging has received virtually no attention in technical literature. In the conventional direct resistivity logging methods only the zero frequency impedance of the formation under study is measured, and no information is obtained regarding its reactive characteristics. Since the use of certain transients appears to offer some advantages in this respect, experiments were performed on a laboratory scale to investigate this possibility. This investigation was limited to a study of a four-electrode array where both the receiving and transmitting electrode pairs are mounted on a logging sonde, and decaying exponential pulses are applied to the transmitting electrodes. THEORY Given an electrode configuration as shown in Fig. I, located in a homogenous medium of resistivity p, if each electrode has an effective radius, r, which is small compared to the spacing, s and a, it is easy to show by integrating the volume resistivity that the input resistance, Rrw, of the transmitting electrodes is Rxw=p/2pr If a capacitor of capacity C, charged to a voltage Em, is suddenly connected to these electrodes, the resulting current, I(t), will then be The voltage transient, E(t), at the receiving electrodes may then be found by substracting the resulting potential at electrode Y from that appearing at electrode Z. and by inserting Eqs. 1 and 2 Integrating Eq. 4 with respect to tim

Jan 1, 1957

By E. C. Robertson

Observations of faults in mines, at outcrops, and in the laboratory lead to the conclusion that the displacement d of a fault increases irregularly but monotonically with the thickness t of its associated fault gouge and breccia, not including adjacent undisplaced jointed rock. The general trend of data points has a slope d/t of about 100. (The correlation coefficient of a logarithmic regression line is r = 0.94.) The rather wide scatter of the points can be accounted for by inaccuracies in measurement of d and t, and by variation in the conditions at faulting of confining pressure, rock type, water pressure, and deformation history. Limestone is an exception to the relation. Until the data can be corrected and refined, the relation should be used only qualitatively for estimating displacement of ore bodies in mines. The suggested relation is based on observations of 48 steeply- dipping normal and reverse faults and nine small flat-dipping thrust faults, with displacement less than 5 km (3 miles). It does not apply to large strike-slip and low-angle overthrust faults because their large displacements are poorly determined and their breccia thicknesses are widely variable.

Jan 1, 1984

By John W. King, S. Ralph Austin

Spurred by recent forecasts of greatly increased demands for uranium by 1980 and beyond, interest is once again focusing on America&apos;s western uranium deposits. One of the principal producers in this area is the Gas Hills district in Wyoming, the site of approximately 12% of the known uranium in the U.S., including past production and current reserves. Located on the south flank of the Wind River Basin, the Gas Hills deposits have been recently studied by the Atomic Energy commission for clues to and guides for discovering similar-occurring ores. The ore deposits are confined to a permeable sandstone unit, up to 350 ft thick, at or near the base of the upper Wind River formation of early Eocene age. The uranium occurs in three principal north- south "ore trends," each of which is about six miles long, one mile wide, and separated from each other by approximately three miles (Fig. 1).

Jan 5, 1966

By F. Weinberg

The distribution of solute during the progressive solidification of dilute Sn-Ag alloys was determined in both solid and liquid as a jbnction of growth rate, rod diameter, temperature gradient, and solute concentration, using radioactive tracer techniques. The results indicated that partial mixing occurs in the liquid during freezing for most of the conditions investigated, approaching complete mixing for larger rod diameters (>2mm) and slow growth rates. Measured solute distributions were fitted to distribution functions based on diffusion controlled solute transport in the liquid state, by treating the normal solute diffusion constant and distribution coefficient as variable solute transport and segregation parameters. Values of these parameters were determined for the growth conditions investigated. Observations were made to determine whether mixing in the liquid was primarily due to volume changes in freezing or to differences in density between solute and solvent. The former effect was investigated using a selected Sn-Bi alloy as a solvent with zero volume change on fusion, and the density effect was studied using vertical solidifications of Sn-In and Sn-Ag alloys, systems having, respectively, very small and large differences in density between solute and solvent. The result indicate that mixing in the liquid cannot be primarily attributed to either volume changes or density differences. THE solute distribution in progressively solidified rods of dilute alloys, in which there is complete mixing in the liquid, is given by the expression1 where C, is the solute concentration in the solid at the point where the fraction g of the material has solidified, C, is the initial solute concentration and k is the equilibrium distribution coefficient. If it is assumed that there is no significant con-vective mixing in the liquid, then the solute distribution in the initial portion of a semi-infinite rod has been calculated to be2 where t is the time from the start of freezing and x1 is the distance in the liquid ahead of the solid-liquid interface at time t. Expressions [1] and [2] describe the limiting cases of solute distribution in the liquid, i.e., complete mixing, or no convective mixing; in practice it might be expected that the solute distribution would be somewhere between these two cases. pfann3 has suggested that Eq. [I] is applicable for partial mixing, as well as complete mixing, if an effective distribution coefficient k1 is used instead satisfactorily describes solute distributions in rods of magnesium, n-g, and b-sb6 alloys that were progressively solidified from the melt without mechanical mixing. The values of kl were observed to depend on the growth rate4-6 and the temperature gradient.6 The purpose of the present investigation was to measure solute distributions in both the solidified rods and the melt as a function of the solidification variables, and to determine to what extent the observed solute distributions could be described by the above theoretical expressions, keeping in mind that expressions [2] and [3] have been derived solely for the case of diffusion controlled solute transport in the liquid and are not theoretically applicable to

Jan 1, 1963

By V. R. Thompson, R. C. Westgren

In a recent paper,1 the solid-solution strengthening of tungsten and tantalum in a portion of the W-T;-MO-C~ alloy system was described. Additions of tantalum and columbium to tungsten led to significant strengthening, and the introduction of dispersions into these alloys was suggested as a means of further increasing strength. Dispersion strengthening of columbium and molybdenum alloys has been studied extensively.2-4 The approach used to dispersion-strengthen molybdenum alloys appeared equally suitable for tungsten alloys, and, therefore, a brief study was undertaken to determine to what extent the introduction of carbide dispersions would strengthen a solid-solution tungsten-base alloy. A base composition of tungsten and 10 to 12 pet Cb was selected; previous work1 had shown that the tensile strength of this solid-solution alloy was 50,000 psi at 3000°F. For the study of the effects of small additions of

Jan 1, 1964

By Felix E. Wormser

REGISTRATION started bright and early Monday morning in the Silver Corridor at the Waldorf-Astoria with Mrs. W. H. Bassett as chairman. What a registration-over 200 ladies! Several joined us from as far away as California and Washington State. Apparently they enjoy our meetings so much that present travel inconveniences didn&apos;t discourage their coming. At noon the ladies joined the men at the All-Institute Luncheon and Monday evening we had our informal dance, which is separately reported. Tuesday morning was devoted to our annual meeting at which all Section annual reports were read. At noon we were all the guests of the W.A.A.I.M.E. at a luncheon at the Port Arthur Restaurant on Mott St. in Chinatown. Many of us rode down on the old 3d Ave. elevated railway-the last of four. It, too, is soon to be torn down. The luncheon was delightfully unusual, with huge dishes of delicious Chinese food on each table. Our chairman, Mrs. Read, who lived in China in her youth chose our menu, and she chose it well, for most of us indulged so heartily that as we arose from the table we felt we couldn&apos;t eat again for 24 hours. Someone donated sherry wine, and boxes of Chinese pencils as favors. We wonder who? All owe a big vote of thanks for this lovely party to Mrs. T. T. Read and Mrs. H. A. Prosser, chairmen, and Mrs. H. W. Hardinge, Mrs. R. Hursh, and Mrs. R. L. Lloyd, vice-chairmen.

Jan 1, 1944