Search Documents

By Harold Vagtborg

Equilibrium vaporization ratios were obtained for light hydrocarbons, nitrogen, carbon dioxide, and hydrogen sulfide in a reservoir fluid containing 35 mole per cent hydrogen sulfide. The data cover the range from 700 to 2500 psia at 154°F. The results of this study are compared with results obtained by other investigators on systems containing less hydrogen sulfide. When large amounts of hydrogen sulfide are present, the equilibrium vaporization ratios for ethane and heavier hydrocarbons are greater than the ratios for systems containing little or no hydrogen sulfide. Large amounts of hydrogen sulfide have the reverse effect on the ratios for methane. Routine PVT studies were performed on the reservoir fluid including flash and differential liberations of the dissolved gas. The pressure-volume relationships of the saturated fluid were also determined. It is shown that the use of published correlations on physical properties of reservoir .fluids can lead to gross errors when applied to systems containing large amounts of hydrogen sulfide. INTRODUCTION Equilibrium vaporization ratios for various components in naturally occurring crude oil and condensate systems have been reported in the literature.1,2,3,4 Recently, several papers have been published with emphasis on non-hydrocarbon components such as nitro- gen, carbon dioxide and hydrogen sulfide.5,6,7,8,9 The increased discovery of reservoir fluids having high concentrations of these non-hydrocarbon components, particularly hydrogen sulfide, has created a need for a further study of their phase behavior. Equilibrium vaporization ratios are known to vary with pressure, temperature, and overall composition of the system.'" It was anticipated that ratios for systems containing large amounts of hydrogen sulfide would differ from the ratios for systems containing small amounts of hydrogen sulfide. Therefore, the present work was undertaken in order to obtain reliable equilibrium vaporization ratios for the reservoir-fluid in question. PROCEDURE The procedure followed was evolved after considerable experimentation on methods of handling the very sour crude. It was found that drying agents (e.g. CaCl2 and CaSO4) absorbed an appreciable amount of hydrogen sulfide from the gas used to prepare the recombined samples. The concentration of hydrogen sulfide dropped as much as 10 mole per cent in a single pass through a 3-ft drying tube. It was also found that when undried gas was agitated with mercury in the PVT cell, a black scum, believed to be mercuric sulfide, was formed and the hydrogen sulfide content of the gas dropped several mole per cent. Because composition changes during a run could not be tolerated, separation of the mercury and sour fluid was necessary. In order to effect this separation, a stainless steel piston, equipped with Teflon O-rings, was placed in the PVT cell between the mercury and the sour fluid. This piston had to be constructed in three parts because

Jan 1, 1955

By D. G. Westlake, E. S. Fisher

The habit planes for zirconium hydride precipitation in crystals of a zirconium have been determined at various hydrogen concentrations. The (10 • 0)planes are the predominant habit planes; some (10 • 5) and (10 -1) planes were observed after charging conditions which pevmitted formation of a surface layer of hydride. No platelets zrlere observed parallel to any of the twinning planes. Mechanisms for em-brittlement due to hydride precipitation are discussed. LANGERON and Lehr1 found, in 1956, that zirconium hydride precipitates in zirconium in platelets lying parallel to (10.0) slip planes. In 1960, Kunz and Bibbz reported observing the platelets in three different families of twinning planes, (10.2) {11.1), and {11.2), but never in the slip planes. The present study was undertaken to ascertain the cause of these seemingly contradictory results. EXPERIMENTAL Two specimens of iodide zirconium were used in the experiments. Specimen I was a single crystal, while specimen II contained three grains. Grain growth was accomplished by the technique of Lange-ron and Lehr. Three faces were ground on specimen I; the first was 2 deg from the (00.1) basal plane, a second was 2 deg from the (10.0) prism plane, and a third was 4 deg from the (12.0) plane. One face was ground on specimen II such that the poles of the surfaces of crystals A, B, and C were as shown in Fig. 1. After the faces were ground on 600 grit silicon carbide paper, they were chemically polished by dipping in a solution of 8 parts hydrofluoric acid, 50 parts nitric acid, and 50 parts water. This removed all cold worked metal from the surface. The samples were charged to various levels of hydrogen content by heating in hydrogen gas which had been purified by reaction with uranium powder. The various charging conditions are shown in Table I. Specimen I was heated to the reaction temperature at the indicated hydrogen pressure and allowed to react until essentially all the hydrogen was used up. Then the temperature was raised for homogenization. Specimen II was charged by making periodic addi-

Jan 1, 1962

By Olaf Hondrum

CHURN drilling equipment at Bagdad consists of two Bucyrus Erie 27-T model drills and one 22-T drill with gasoline engines. The drilling tools weigh approximately 1600 lb. The holes are drilled with 7-in. bits which are heated in an oil burning furnace and sharpened in an electrically powered bit sharpener. A service truck brings the bits to the drills and takes the dull bits back to the shop. The bits weigh around 250 lb. when new and are handled by drill crews without any mechanical handling device. When the management decided to start open- pit operations in 1945 the ruggedness of the terrain was one factor that led to the purchase of the small 22-T model drill. The orebody lies on both sides of Copper Creek Canyon. The sides of the canyon are steep and are cut by numerous narrow branch gullies. The drill had to travel over roads that were narrow and steep. It proved adequate for drilling the capping formation and is still in use.

Jan 1, 1950

By E. K. Olson

Eagle Mountain mine of Kaiser Steel Corp. began production in 1947 when the direct shipping ore contained 51-56% Fe. The high grade, wide ore face and low stripping ratio ores were rapidly depleted and Eagle Mountain required processing plants for upgrading and more efficient mining equipment. During 1970-71 total annual pit tonnage averaged 56 million tons of material ranking the Eagle Mountain Mine as the fourth largest in the country. Ore production averaged 12.5 million tons requiring a stripping ratio of 3.5: 1. During this period mining activities were scheduled for a three-shift, seven-day operation. The present mining rate is about 30 million tpy on a two-shift, five-day schedule.

Jan 12, 1972

GOVERNMENT ESTABLISHES DIVISION OF ENGINEERING Government supervision of employment for technical men has been inaugurated by the United States Employment Service, through the establishment of a Division of Engineering, with A. H. Krom, of Chicago, formerly Secretary of the American Association of Engineers, as Director. War demands on the engineering profession have already caused a serious shortage of men with mechanical designing experience and those with practical experience in chemical engineering. At present the professional organizing mediums reach less than 20 per cent. of the estimated 300,000 technical men in the country. This is not a satisfactory arrangement for war times. All the technical men of the country must be reached and, in addition, all men with technical experience must be carefully registered so that they will be immediately available. The advantages of such a governmental registering and systematizing of employment will be apparent at once, to the engineer. Considering that this is principally an engineer's war, the importance of Federal direction of distribution and conservation of the technical service of the country is apparent. The Service will he started through the office of the Director of Engineering, 29 S. LaSalle St., Chicago. All technical men desiring to register for emergency Government work or permanent advancement in positions meeting their qualifications, are urged to volunteer at once for registration, classification and employment.

Jan 8, 1918

Discussion of the paper of ROSWELL H. JOHNSON, presented at the New York meeting, February, 1915, and printed in Bulletin No. 98, February, 1915, pp. 221 to 226. A. C. LANE, Tufts College, Mass.-About a year ago Mr. Washburne read a paper on the same characteristic oil-sand waters, discussing their chemical character, and the possibility of their chemical character being modified by adsorption in passing through the shale. We are used to consider circulation as being in one stratum, and I have often gone so far as to think that 2,000 or 3,000 ft. clown I could recognize the chemical character as in part connate to a given water. For instance, the St. Peter sandstone, far underneath oil sands, seems to retain' a relatively fresh and peculiar character. I am, therefore, tempted to ask the writer if in his experiments lie has made any test to see whether the chemical character of these waters is also changed, where there is any adsorption, so that the water passing through these fine-grained beds should leave behind its salt as well as its oil. In many cases salt-waters are associated with oil and-gas. A second question has occurred to me. In these days when we hear a good deal about oil flotation, may it not be well to repeat these experi-ments with pyritic concentrates, and see if they observe precisely the same with regard to the selective accumulation of oil and gas. ROSWELL H. JOHNSON.-I thank Profesor Lane for bringing this question forward. I recognize its importance, but. am not able to say I have any data upon that point. It is also very interesting in connection with Dr. Day's hypothesis of fractional filtration, and we may very easily get something happening to the water corresponding in some degree to what we get with oil. D. B. REGER, Morgantown, W. Va.-Mr. Johnson in his paper states his belief that the oil is formed originally from organic matter in the shale, and is forced out of the shale into the porous reservoir of the sand above the shale. He states further, that as you go deeper iii the measures where there is an increasing overburdens, the oil becomes less and the gas increases in large proportion, or lie says that the oil is forced back out of the sand by pressure, into the shale.

Jan 5, 1915

By W. A. Foster

NINETY years after the Riddle nickel deposit N was discovered in Oregon in 1864, Hanna Coal & Ore Corp. began mining operations. Until 1954 much prospecting and preliminary development work had been done on the property, but no ore had been shipped other than for metallurgical testing. The deposit is being explored by churn drilling and trenching, and a few test shafts have been put down for the purpose of studying the ore in place, determining volume and moisture factors, and gathering bulk samples for pilot plant and smelter tests. In churn drilling, 6-in. casing is driven down 2 or 3 ft behind the drill bit and bottomed at each 5-ft interval. All the sludge for each cased 5-ft interval is dumped through a splitter and one eighth is saved and analyzed. Drillholes are stopped after going through the ore zone and penetrating fresh peridotite in which the nickel content is less than 0.5 pct.

Jan 8, 1957

By Edwin B. Wilson, Joseph W. Leonard, Richard W. Borio

preparation of specification coals for the utility industry is approached from the standpoint of a cooperative effort with the power company to assure that the shipped product will be a noncorrosive coal. Selective mining, coal preparation, the use of additives, and coal blending are mine-site techniques proposed as means for upgrading corrosion-retarding constituents of utility coals (CaO and MgO) while, at the same time, reducing the concentration of those constituents of coal (Na20 and K,O) which cause corrosion. Data obtained from large-scale boiler testing in combination with bench-scale physical and chemical tests are used as a basis for the formulation of mine-site procedures to improve coal combustion utilization. Electric power generation remains the greatest market for coal in the United States. A major reason for this strong market has been the ability of the coal industry to supply a superior product for combustion while maintaining competitive prices. Now that the coal industry is engaged in intensive competition with nuclear power for future energy demand, it becomes ever more imperative that superior coal products are produced. One important problem when burning some coals is a liquid phase corrosive attack on boiler tube metal in the superheater and reheater areas of the furnace where steam temperatures may exceed 1050°F. In addition to causing power outages and high maintenance costs, corrosion is a continuing barrier to the future development of more efficient steam cycles which permit lower generation costs when using coal. Research methods of the past which have been directed at finding solutions which could be applied at the power plant site have been only partially successful and are generally costly. This paper contains a suggested --method of corrosion control through investigation of the problem at the source of the trouble—the coal supplier facility. It is proposed that mine-site pre-ventative procedures be considered as an effective means of cooperative corrosion control between the power company and the coal supplier. Economic justification must be applied to the individual situation. This paper is based on recent work by Combustion Engineering, Inc. and the Coal Research Bureau of West Virginia University under a contract from the Department of the Interior Office of Coal Research.',' Results which are of importance to this discussion may be summarized as follows: 1) The alkali minerals of coal (Na2O and K2O), as measured by an acid leaching process, can be related to corrosion rate in utility boilers. As these constituents increase in a coal product, its corrosiveness can be expected to worsen. 2) The alkaline-earth minerals contained in coal, reported as total CaO and MgO reduce corrosiveness 2s their concentration increases. 3) Naturally occuring, alkaline-earth-bearing materials, such as limestone and dolomite, may be added to a coal to reduce its corrosiveness. 4) Coals with very low iron contents tend to be less corrosive. These results provide the groundwork for examination of the system of operations which occur at the supplier facility from the seam face where mining is begun to the point of loading for shipment. The Mining System Fig. 1 is a cross section of one of the typical coal seams (designated coal A) that was boiler tested during this research program. This seam is overlain by material which consists primarily of a gray-black shale. In the lower third of this seam, there exists a thin rock parting of less than 4 in. in thickness which is consistent throughout the seam. The floor material is fireclay. In order to examine mineral distribution throughout this particular seam, the Coal Research Bureau collected a

Jan 1, 1971

By H. J. Levinstein, W. H. Robinson

A method of chemically polishing silver for metal-lographic examination has been developed. The samples are prepared by polishing on 0, 2/0, and 3/0 paper. They are then polished on 600 micro-cut paper, followed by a final mechanical polish on a cloth containing 5µ diamond paste. The samples are then chemically polished in a solution of 100 cc of saturated chromic acid and 5 cc of a 5 pct HC1 solution. The chemical polishing is performed by swabbing with a cotton ball saturated with the solution. During the chemical polishing, the sample is rinsed frequently in running water. Polishing in this manner for 5 min is sufficient to remove the strained material from the previous polishing operations. The amount of material removed is approximately 4µ/min. The surface obtained is flat and free of pits. Fig. 1 is an interference micrograph of a silver surface polished by this technique. If the solution employed is of improper HC1 content, an interference color film will form on the sample. This film can be removed either by swabbing with a cotton ball saturated with ortho-

Jan 1, 1962

By R. Schuhmann

Distribution of material in the fine sizes of a comminution product generally is well represented by the empirical equation' y = 100 (x/k)a [1] in which y — cumulative percent finer, x = particle size, a -= distribution modulus, and k = size modulus. Charles3 found that the energy consumption in comminution is usefully expressed by another empirical relation, E = Ak(1-D) [2] in which E = energy input per unit volume of material, A = a constant, k = size modulus based on Eq. 1, and n = a constant; (1-n) is the slope of a plot of log E vs log k. Holmes3 has presented energy equations similar to Eq. 2. The constants a and n in Eqs. 1 and 2 have been shown to depend both on the nature of the material and on the comminuting device. Moreover, Charles showed that within experimental error a and n are a — n+1 = 0 [3] Combining Eqs. 2 and 3, E = A k-a [4] In the first sections of this article it is shown that the energy equation, Eq. 4, can be derived directly from the size distribution equation for the fine sizes, Eq. 1. The derivations are made without assuming any of the specific relationships between energy and particle size which have been common in previous literature. For comminution processes in which Eqs. 1 and 4 adequately represent the experimental data, the constant A in Eq. 4 is found to be a simple and useful inverse measure of grindability. That is, A is the energy consumption per unit volume of comminution product finer than unit size as determined from the straight line portion of the log-log plot of the size distribution. These considerations all lead to a unifying hypothesis of comminution mechanism from which both Eq. 1 and Eq. 4 can be derived. Finally, it is pointed out that this hypothesis raises serious questions as to the significance of the Rittinger hypothesis, the Kick hypothesis, and other theories in which energy numbers are systematically assigned to various size fractions of comminution products in order to calculate theoretical energy consumptions. Derivation of the Energy Equation from the Size Distribution Equation: For simplicity, consider the comminution of 100 volumes of a feed material of relatively uniform particle size. The comminution process may be considered as the summation of many individual and independent comminution events. The extent of comminution is most easily expressed as the number of comminution events, z. In the first derivation, the key assumption is that the characteristics of the comminution events in a given crushing or grinding process are substantially constant and do not vary with the progress of the comminution process. Accordingly the characteristics of an average comminution event may be defined. In one such event, a quantity of energy $E is applied to a single particle of size f and volume $v. The crushing of this particle produces fine particles with a size distribution similar to that given by Eq. 1: yw=100(x/ka)a0 [51 In this equation yo, a0, and k0 are used to characterize the product of an individual comminution event rather than the product of the comminution process as a whole. In using Eq. 5, we will not be concerned with values of x close to the feed size f and will therefore assume only that the equation is applicable to the finest sizes of the material. In 100 volumes of total product, the actual volume of product finer than x from a single comminution event, or dy, is given by The total volume of material below size x, resulting from z events, is then given by y = z(dy) =z(dv) (x/ka)a0 =" Eq. 7 reduces to Eq. 1 when we let a, = a and [8a] z =100/dv (ka/k )1 or k = ka (zdv/100)-1/a [8b] Eq. 8a shows that the distribution modulus of the comminution product is the same as for the product of an individual comminution event. Eq. 8b shows how the size modulus of the comminution product k varies with the extent of comminution as measured by the number of events, z, or as measured by the fraction of the feed actually subjected to com- minution1 zdv/100. The energy input to 100 volumes of total feed, or 100E, is the sum of the energy inputs for all the comminution events: 100E =z (dE) [9]

Jan 1, 1961

By C. S. Barrett, A. Smigelskas

There have been no publications of the deformation and recrystallization orientations of the metal beryllium, yet pronounced textures would certainly be anticipated since it is close-packed hexagonal in structure. Having an axial ratio approximately that of magnesium, beryllium probably deforms by nearly the same slip and twinning mechanisms that operate in magnesium, and the textures are likely to be similar or but slightly different from the magnesium textures. In the tests reported below this is found to be the case; the textures are found to differ from those of magnesium only in the details of the scatter from the average orientation. This report covers not only samples rolled at room temperature, but some rolled at elevated temperatures. Since magnesium has been suspected by some investigators of altering its crystallo-graphic deformation mechanism at elevated temperatures, it was considered possible that beryllium might do so and alter its textures accordingly. No pronounced alterations were found, however. Unfortunately, the theory of deformation textures is not in a state of development that permits one to deduce the deformation mechanism from a knowledge of the textures, which means that the similarity of textures at different rolling temperatures, reported here, cannot be taken as definite evidence that the deformation mechanism is actually the same at all temperatures. The general similarity of the deformation textures of magnesium and beryllium also extend to the recrystallization textures of the two metals, judging by the pole figures for recrystallized sheet presented in this report. Samples were prepared in the form of composite sheets made up of small pieces stacked in a pile. Each piece was trimmed with scissors so that an edge was parallel to the rolling direction, dipped in paraffin, and assembled into the pack by aligning it under the cross hair of a microscope. As the desired orientation was obtained on each piece it was secured in place by touching with a hot wire to melt the paraffin. A stack of ten or fifteen pieces was built up in this way, then trimmed to the shape of a T; the portion to be X rayed was then etched to the shape of a wire about 0.045 in. diam with 6N HCl. This method of shaping the sample is a modification of that used by Bakarian on magnesium.' The absorption of the rays in the sample was so slight that it caused no difficulty in interpreting the films. Exposures were made with a 0.030 in. diam pinhole, using molybdenum radiation (40 kv, 25 ma, Type A film at 5 cm, 2 to 3 hr exposures). With the recrystallized specimens it was found necessary to oscillate the specimen so as to reduce the spottiness of the lines. A range of oscillation of 5" was SUB- cient to produce reasonably satisfactory patterns, though the quality was somewhat inferior to that of the deformation texture patterns, and only two degrees of intensity were read from the arcs on the films. Typical photo-grams for each of the deformation textures and the recrystallization texture are assembled in Fig 1. The pole figures were plotted in the usual way with the intensity of the various portions of the diffraction rings estimated by eye. Seven to nine films were made of each sample and each was carefully read in plotting the pole figures. Typical series included exposures with the beam normal to the rolling direction and at 11, 26, 41, 56 and 71" to the cross direction, plus two exposures with the beam normal to the cross direction, and at 11 and 79" respectively to the rolling direction. The rolling was in each case considered sufficient to develop the final texture: the reduction by cold rolling was 84 pct (from 0.0045 to 0.0007 in. thickness), following prior hot rolling in longitudinal and transverse directions and recrystallization; the reduction by hot rolling at 800°C was 90 pct (0.010 to 0.001 in.), following similar prior treatment; the reduction by rolling at 350°C was 88 pct (from 0.005 to 0.0006 in.) after similar prior treatment. The recrystallization texture was determined on a sample rolled at 350" to a reduction of 88 pct (0.0165 to 0.002 in.) after similar prior treatment, then mounted between steel strips to keep it flat and annealed at 700" in an atmosphere of argon. Discussion of Results The results of the X ray determinations are assembled in the pole figures of Fig 2, 3, 4 and 5 for rolling at

Jan 1, 1950

By Joachim J. Hauser

Experiments on latent hardening were peyformed by compressing single crystals along a direction perpendicular to the tension axis. The slope and length of easy glide in the tension test were found to depend only on prior deformation in the same slip plane. Prior deformation on a different slip plane changes the stress level of the resulting stress-strain curve. The yield points appearing upon reloading after prior extension and unloading were related to the end of easy glide. SEVERAL researchers have studied the latent hardening due to deformation of a crystal by slip on a slip System after prior deformation. These experiments can be divided into those in which the prior deformation was on the same plane as the subsequent and those in which the two deformation processes were in different planes. In the former category are the experiments of Buckley and Entwistle,1 Parker and washburn,2 and Haasen and Kelly.3 The latter case has not been studied systematically; it was the main purpose of this investigation to produce this type of latent hardening and explain the results in terms of the existing theories of work hardening. In general, tension producing slip on a certain slip system can be preceded by tension, transverse compression or longitudinal compression, each with predictable dislocation movement and intersection. The intersection of dislocations can lead to glissile or sessile jogs, Cottrell-Lomer locks and other sessile dislocations. The effect on the stress-strain curve could depend on which combination of the former mechanisms is operating. Haasen and Kelly3 have studied the yield points which occur in aluminum and nickel single crystals upon reloading after prior unloading in a tension experiment. They attributed this effect to the anchoring of dislocations occurring during unloading. As Cottrell and stokes4 have shown that dislocations cutting through the "forest" could only lead to reversible changes, they attributed the anchoring to the formation of sessile dislocations during unloading. However, different kinds of sessile dislocations could be formed during unloading, and it was the purpose of this experiment to determine whether Cottrell-Lomer locks are responsible for the yield effect and for the end of easy glide. The case where a longitudinal compression is followed by tension along the same axis is commonly referred to as a Bauschinger test. This type of effect was studied by Buckley and Entwistle1 on aluminum single crystals and by Parker and washburn2 on zinc single crystals. In such a test, the tension and the compression activate the same slip plane with opposite slip directions. The use of sideways compression in the present experiments permits the activation of different types of slip systems and the study of their effect on the easy glide region and on the transition between the elastic and easy glide region. The theory of seeger5 for the flow stress in fee materials is applied to explain the latent hardening. EXPERTMENTAL PROCEDURE All the single crystals used in this investigation had an axial orientation close to <210>, called the "0.5" orientation. This is the orientation for which the tensile axis is 45 deg from both the slip plane and the slip direction. The single crystals were grown from the melt under a helium atmosphere using milled graphite boats,=at a rate of 8.6 mm per min. The silver used in the experiment was 99.98 pct pure. The single crystals had a square cross section about 0.9 by 0.9 cm and a length of 14 cm. The orientation of the specimen was determined within ±2 deg by the Laue back-reflection method. The specimens were annealed at 940&apos; ± 2°C in a helium atmosphere for 24 hr and then furnace cooled over a period of 7 hr. The specimens were electropolished in a solution of 9 pct KCN in water. The specimens were tested in a soft-type tensile machine (the load is prescribed) up to 3 pct strain. The stress was increased continuously at approximately 30 g per mm2 per min. The strain was measured over a 5 cm gage length with a mechanical extensometer employing an optical lever. The strain and stress were measured with accuracies of i 2 X 10-5 and ± 2 g per mm2, respectively. The remainder of the stress-strain curve up to 20 pct strain was obtained in a hard-type tensile machine (the strain rate is prescribed). The strain and the stress were measured in that machine with an accuracy of ±2 pct. The compression tests were performed in the hard-type machine using accurately machined steel blocks without lubrication. The blocks were used so as to apply a uniform compression over a length of 13 cm. The strains were measured on the hard-type machine and with a micrometer.

Jan 1, 1962

By Henry M. Otte, Ralph P. I. Adler

The changes of line position and integral line breadth in the X-ray diffraction pattern of a polycvys-talline Cu-30Zn tensile test piece, incrementally loaded (and unloaded) up to fracture, have been an-alyzed in detail. The stacking-fault probahility, cv, increased linearly with increasing strain, E, wheveas the effective domain size, De(hkl), decreased with decreasing E-1 Over the greater part of the stress-strain curve the rate of work hardening was essentially constant (about 86 kg per sq mwz), and could be correlated with the slope of stage II of the single-crystal stress-strain curve. Consequently the theories of work hal-dening (particularly those parts relating to stage 11) as developed by Mott and Hivsch and others could be applied to the observations made on the polycrystalline brass. A relationship of the form Aa = Aao - MhklEhkl between the change, Aa, in the extrapolated lattice pararneter and the rvns strain, Ehkl, was derived and found to fit the results acceptably well. From this and other relationships developed in the papev it was estimated that the equilibrium stacking-fault energy of Cu-30Zn was between 8.4 and 12.5 ergs per sq cm, in fuirly close agreement with the (corvected) value obtained by Howie and Swann (1961)43 using transmission electron microscopy. The theory of work hardening in the jorm developed and recently presented by Hirsch (1964)3 successfully described all the pvesent observations. In order to test certain aspects of the theories of work hardening, as developed by Mott,1 Hirsch,2,3 Seeger et el,4-7 and others (for review see Nabarro, Basinski, and Holt8), several recent investigations have been concerned with relating the dislocation density, p, with the shear stress, 7 (and strain, y), applied to the specimen. The results of these investigations have shown that the square root of the dislocation density appears to be linearly related to the applied shear (or flow) stress for fcc as well as bcc metals and alloys. Furthermore, the relationship appeared to apply not only to the deformation of poly-crystalline specimens, but also to stages I and I1 of the deformation of single crystals. An expression of the form has thus come into wide use. Here b is the Burgers vector for a total dislocation, G is the shear modulus, and 70 and q are constants. A review9 of available values of q shows it to have values (at room temperature) in general between 0.3 and 0.6. Forms of Eq. [1] can be deduced from, or predicted by, the current theories, and the various constants adjusted so that they are compatible with the experimentally found value of q . No unique relationship has yet been found between the dislocation density and the applied shear strain. There are several serious objections to the use of Eq. 11]. In the first place, it relates the shear stress to the density of the dislocations without regard to their arrangement, type, or distribution; the significance of the relation may therefore be justly questioned.5 In the second place, the values of the experimental quantities usually substituted into Eq. [11 are those of the applied shear stress and the total dislocation density measured after unloaditzg. The dislocation density value that should in fact be used is that for the mobile dislocations present in the specimen when under the applied load.* Finally, in cases where the values used for p, the dislocation density, are those obtained by electron microscopy, p is subject to considerable error,&apos; both systematic and random. The corrections to be applied are still controversial. Dislocation densities can also be measured by etch-pit and other techniques,&apos;&apos; each having their specific limitations. An objective of the present investigation has been to obtain information about the dislocation configyration and distribution by analyzing the changes in the position and shape of X-ray diffraction profiles as a function of deformation. The X-ray techniques employed, also open to criticism, have certain advantages, however. Thus, although the X-rays diffract only from the surface layers to an effective depth of about 20 p, the measurements can be made while the specimen is under load. The value of the dislocation density obtained by the X-ray method is also subject to errors, which are different from those of the electron microscope. Though a considerably larger volume of material is sampled by the X-rays, thereby reducing some of the statistical errors inherent in the electron microscope data, the information obtained is less detailed and is dependent on the method of analysis used to obtain a value for the dislocation density. Nevertheless, important observations can be made because the aforementioned advantages outweigh some of the limitations. In the present paper the X-ray method is briefly described and applied to a brass specimens deformed in tension. The results are then discussed in terms of some of the current concepts of work hardening. 1) EXPERIMENTAL PROCEDURE Details have already been extensively published elsewhere11-14 and therefore will only be dealt with briefly here. 1.1) Materials and Specimen Preparation. Commer-

Jan 1, 1968

By Albert D. Brokaw

THE accompanying chart was devised to provide a rapid and simple method of correcting for temperature and compressibility (deviation from Boyle&apos;s law) of gas under relatively high pressures and temperatures, such as are encountered in many deep reservoirs. The chart was prepared by interpolating for the desired values in the experimental data of Burke and Keyes1 and Kvalnes and Gaddy2 on the compressibility of methane, after adjusting their results from 0°C. to 60°F. and combining the correction factors for compressibility and temperature into a single multiplier, which, applied to the product of pressure and reservoir volume, gives at once the volume at one atmosphere (14.7 lb. per sq. in. abs.) and 60°F. The relationship 0f this multiplier to the compressibility factor Z, as used in most discussions, is simply: [Multiplier = 460° + 60°ZT –] where Z is the compressibility factor and T the absolute temperature (Rankine). Fahrenheit temperatures are shown on the vertical axis and pressures in pounds per square inch absolute on the horizontal axis. Correction factors or multipliers at intervals of 0.05 from 0.55 to 1.40 have been plotted on the chart and are calculated t0 give volume of gas at one atmosphere pressure (14.7 lb.) and 60°F. The operation is as follows: The reservoir volume, times the number of atmospheres pressure, times the multiplier, gives the volume of gas measured at one atmosphere (14.7 lb. per sq. in.) and 60°F. For example, a reservoir is estimated to have a volume of 10,000,000 cu. ft., bottom-hole pressure is 2940 lb. per sq. in. and temperature is 184°F To make the correction for methane, follow the 184° line horizontally to the 2940-lb. pressure line. The intersection lies between the 0.85 and 0.90 correction lines, and by interpolation we may estimate the multiplier at 0.863. The computation is simply: [ ] Using the chart for methane prepared by Prof. G. G. Brown3 and his associates, the multiplier is found to be 0.867. Details 0f computation are as follows: Correction factor to apply to PV to correct for deviation from Boyle&apos;s law and adjust to measurement basis of 60°F.: [ ]

Jan 1, 1941

L. D. GODSHALL, Everett, Washington: This very interesting paper cannot fail to command the attention of every one who has ever had experience in the amalgamation of gold-ores. I wish to call attention to three very important facts brought out very prominently by the paper, namely: 1. The extent of accumulation of amalgam on copper plates in the form of scale, not removable in the ordinary manner; 2. The change in the relative quantity of the two metals in the amalgam as we. recede from the battery-discharge; 3. The difference in fineness of the bullion obtained from the above-mentioned scale as compared with the bullion from the daily clean-ups. From Mr. Bayliss&apos;s figures we find that during the life of the plate in question 14,942 tons of ore were crushed, yielding amalgam of the value of $5.03 per ton, or a total value of $75,158.26. The amalgam accumulating on the plate during this time as scale, we find to have had a value of $8340.54, or $0.558 per ton of ore treated, representing 11.09 per cent. of the total amount of amalgam saved in the ordinary clean-up; or, taking the amalgam saved by daily clean-up plus the amalgam-scale as representing the total saved on this plate, or 100 per cent., we find that the daily clean-up saved 90.01 per cent., while the scale represented 9.99 per cent. The above figures do not include some additional amalgam still adhering to the plate after scale had been removed. We are told that this was not an exceptional case at the Drum Lummon, but that other plates have even yielded a third more than the one in question. The interesting query now comes up, whether this experience at the Drum Lummon is exceptional or universal at all mills; and another question arises, as to how long such an accumulation might continue,

Jan 1, 1897

By A. Becker, J. A. Slankis

Equipment has been developed to utilize natural 8 Hz electromagnetic fields to measure rock resistivities. Telluric and magnetotelluric surveys have detected resistivity variations associated with geological contacts and metallic sulfide deposits. The fundamenfa1 premises of these methods are illustrated by the results of surveys across a Pleistocene-Precambrian contact in the Ottawa Valley and a near-surface sulfide deposit in Northern Quebec. Such interfaces are characterized not only by variations in apparent resistivity, but also, unexpectedly by the spatial anisotropy of the electric fields and the presence of a strong vertical magnetic field component in their vicinity. Standard geophysical electrical and electromagnetic methods (Heiland, 1940) for the determination of the electrical properties of the ground and the search of good electrical conductors necessitate the use of a transmitter and receiver which are coupled galvanically or inductively through the ground. The electrical properties of the ground are deduced from either the transfer function, or the impulse response, of the transmitter — ground — receiver system. Where deep penetration is desired these methods require powerful transmitters whose weight and size increase the cost and reduce the speed of operation. It is possible however, to resort to another class of electrical prospecting methods which employ ambient, natural electromagnetic fields in place of a transmitter.&apos;-&apos; In the audio and subaudio frequency ranges, these fields are generated by thunderstorm activity. At some distance from the seat of the disturbance, the e.m. fields propagate as plane waves with a horizontal magnetic field component. The incident wave, of course, induces currents in the ground. Where the ground is homogeneous the relation between the horizontal magnetic and horizontal electric fields vectors is particularly simple:&apos; /E/ = \[SpT/H/ (1) where: /E/ = magnitude of horizontal electric field in millivolts/kilometer (RMS) /H/ = magnitude of the orthogonal inducing magnetic field in milligammas (RMS) p = rock resistivity in ohm-meters i = frequency of measurement in c/s In practice, the ground is seldom an homogeneous half space, lateral conductivity variations exist, (in the case of base metal prospecting these are the features actually sought) and the two field vectors are no longer simply related. The ratio of E to H is still useful, however, for the determination of an "apparent" ground resistivity. From a theoretical view point, the general problem of a two dimensional fault or dyke anomaly can be separated into two distinct cases. In the first case, where the e.m. energy propagates in a direction normal to the strike, the horizontal magnetic field remains constant and is oriented along the strike of the formation.3 As shown by d&apos;Erceville and Kunetz," all the information about the anomaly is contained in measurements of the electric field component. In fact, away from the interface, the electric fields are proportional to the square roots of the resistivities:

Jan 1, 1970

By John H. Hall

The Frémont test for measuring the energy consumed in breaking a notched bar of steel is not so well known in this country as it deserves to be. The test specimen used in this test is about # by 6 by about 16 in., notched with a hack saw on the lower side to cause the piece to break at a fixed point. A weight of 10 kg. falling 4 m., and provided with a knife or chisel which strikes the specimen, breaks the test piece by impact. The residual force in the falling weight after it has broken the specimen is recorded by a suitable device, and the difference between the total energy and the residual energy of the weight (in kilogrammeters) is the force consumed in breaking the specimen. An experience of several years with the Frémont testing machine has shown its great value in readily detecting brittleness not revealed by tensile testing or slow bending testing. In this paper it is proposed to discuss (1) the supersensitiveness of the test as applied to cast steel and (2) its value in revealing the effect of heat treatment under certain conditions. In testing coupons cut from castings heat treated by quenching and annealing, attention was drawn to the wide variations in the value of the Frémont test of specimens cut from different parts of the coupon. The latter was of the form and dimensions shown in Fig. 1, and Fremont test pieces were cut from two parts of this coupon, marked A and B in that figure. The results of the tests are shown below, tests A and B in each instance being from the same coupon: A. B. A. B. Coupon. Kilogram- Kilogram- Coupon. Kilogram- Kilogram- meters. meters. meters. meters. 1,........ 12.0 12.5 9,........ 27.5 32.5 2,........ 11.0 32.5 10,........17.5 31.0 3,........ 11.5 30.0 11,........ 14.5 31.0 4,........ 20.0 33.0 12,........ 15.0 27.5 5,........ 17.5 33.0 13,........ 19.0 30.0 6,........ 17.5 20.0 14,........ 17.5 25.5 7,........ 17.5 13.0 15,........15.0 30.0 8,........ 10.0 30.0

Jan 1, 1914

By R. N. Woody, S. J. Work

Crushing development at Duval Corp.&apos;s Sierrita concentrator in Sahuarita, Ariz., has been a continuing effort since plant startup in January 1970. The original crushing system was designed to produce 65 000 t/d (72,000 stpd) of ore. However, in the summer of 1970 the Sierrita plant was averaging only 43 000 t/d (47,000 stpd) due to coarser than expected secondary crushing plant feed, lower than design crusher operating availability, and inability to achieve design tertiary crusher power draught at an acceptable hydraulic support pressure.

Jan 4, 1979

By C. E. Gregor

Current modern trends in mining show that hoisting shafts are being expected to fulfill an important ventilation function. However, where rigid guides and supporting structures are mandatory, ventilating power costs will be high, unless the transverse structures (shaft sets) are streamlined. In the complex configurations of hoisting shaft furniture patterns, either for original design purposes, or for the adjustment of an existing shaft, a useful degree of aerodynamic optimization, by reduction of overall resistance, can only be effectively evaluated by model studies in a special purpose wind tunnel, as described herein. The author has shown that, in one particular case, an annual power cost saving of more than $50,000 was indicated, mainly by the selection of buntons and dividers of improved aerodynamic profile. Mining companies are now realizing the advantages that can accrue through proper attention to the aerodynamic aspects of mine shaft design. With progressive demands of civilization for an ever greater supply of coal and metals, and with greater depths of working, higher rates of extraction, advanced degrees of mechanization, and improved standards of environmental health and work comfort, shaft design is becoming an extremely important aspect of mining operations. In addition, because the cost of sinking, equipping, maintaining, and operating a mine shaft is continually increasing, there is a greater incentive to use a shaft for the maximum duty, consistent with economy. The current natural tendency is therefore to sink multi-purpose shafts, to install as much equipment as is safely and effectively possible to operate; and then, over and above all these functions, to use the shaft to its maximum possible ventilating capacity, as a major, or auxiliary, airway. Clearly, this latter additional function can only be employed at a significant cost, since the most economic operating airways are smooth-lined and devoid of internal rigid furniture. It is true that hoisting functions can be carried out in such shafts if rope guides are used, but only under restricted conditions. Where a manway must be provided, fixed guides and supporting structures are mandatory, and ventilation costs become accentuated. It is generally recognized that the prime element of cost in ventilating a mine can be represented by the power required to drive the fan unit. It is also known that the largest component of total mine resistance is that of the downcast shaft, where this shaft is equipped with rigid guides for hoisting purposes. The pressure loss varies directly as the resistance of the shaft, in accordance with a modification of the Atkinson equation p = RQ2/3600. Furthermore, the air horsepower drawn is given by the equation AHP = (p x 0/33000. Therefore, the power required to drive the fan unit varies as the resistance of the shaft and the cube of the air quantity. Clearly, if Q is a specified minimum, then the only way to minimize the pressure loss (and the power costs) is to reduce the shaft resistance R. (See Table I for a list of symbols.) The resistance to airflow of a shaft equipped with rigid guides and supporting structural sets consists of two components which, for the sake of analytical simplicity, can be regarded as additive. 1) Frictional resistance, represented by the viscous frictional forces within the boundary layer, as air flows along the surfaces of the walls and the periphery of the vertical elements (guides, pipes, cables, ropes, etc.) of the furniture. The friction loss can be readily calculated by the Atkinson equation, after selection of a suitable value for the friction factor K from the McElroy compilation.&apos; KxLxO xQ2 5.2 xA3 Friction loss can be minimized by lining the shaft walls (particularly if of circular or elliptical cross-section) with a smooth continuous lining of monolithic concrete.

Jan 1, 1968

CONTENTS PAGE Rae, Colin C.-A Possible Origin of Oil. Discussed by S. Linker, Colin C. Rae... 2 Cottingham, Kenneth.-Subsurface Conditions on Portion of Arches Fork Anticline. Discussed by David B. Reger 6 Moyer, W. Irwin.-Time to Pay Out as a Basis for Valuation of Oil Properties. Discussed by H. J. Smith 9 Pogue, Joseph E.-Future Demands on Oil Industry of United States. Discussed by James O. Lewis 11 J. J. Walsh.-Coa-lmine Ventilation. Discussed by W. B. Daly, J. J. Walsh, R. R. Sayers, H. H. Stock, George S. Rice, James W. Paul, D. Harrington, T. D. Thomas 15 Longyear, Robert Davis.-Diamond-drill Sampling Methods. Discussed by Ira B. Joralemon, J. J. Rutledge, E. C. Harder 19 Joralemon, Ira B.-Sampling and Estimating Disseminated Copper Deposits. Discussed by J. Parke Channing, John E. Hodge, E.E. Hunner, B. B. Gottsberger, W. Y. Westervelt, W. O. Hotchkiss 20 Boericke, W. F.-Sampling and Estimating Zinc and Lead Orebodies in Mississippi Valley. Discussed by J. Parke Channing, Arthur Thacher 24 Daly, W. B. and Linforth, F. A.-Organization of Mine Sampling at Anaconda. Discussed by George A. Packard, W. B. Daly, B. B. Gottsberger 25 Norris, E. M. and Rahilly, H. J.-Mine Fires. Discussed by R. Dawson Hall, W. B. Daly, Frank Haas, D. Harrington, Robert E. Tally 26 Raymond, R. M.-Safety Practice for Hoisting Ropes. Discussed by B. F. Tillson, Graham Bright, Rudolph Kudlich, J. F. Howe, Robert Peele, H. G. Davis. 30 Howe, J. F.-Use of Wire Rope in Mining Operations. Discussed by Horace F. Lunt, J. F. Howe, B. F. Tillson 36 Tanner, W. N., and Jaccard, F. C.-Wire Rope and Safety in Hoisting at Butte Mines. Discussed by Horace F. Lunt, W. B. Daly, C. L. Colburn, William Kelly, Robert Peele, B. F. Tillson, Graham Bright, Charles E. Locke 38 Richardson, A. S.-Ventilation of Butte Mines of Anaconda Copper Mining Co. Discussed by D. Harrington, Chas. A. Mitke 42 Stuart, Charles E.-Storage-battery Locomotive as Applied to Mine Haulage. Discussed by Howard N. Eavenson, Charles E. Stuart, William Kelly, Arthur Thacher, W. H. Patton, Graham Bright 45 Woodward, C. D.-Electric Haulage Systems in Butte Mines. Discussed by William Kelly, Graham Bright, Howard N. Eavenson, C. E. Arnold, Gerard B. Rosenblatt, K. A. Pauly 47 Harrington, D.-Efficient Ventilation of Metal Mines. Discussed by R. E. Simpson 52 Otagawa, Masayuki.-Mining Methods at the Ashio Copper Mine. Discussed by Horace V. Winchell, D. W. Brunton 52 Stoek, H. H. and Clagett, Thomas H.-Coal Mining Methods. Discussed by P. D. Browning, G. L. Cox, Erskine Ramsay, Frank Haas, George S. Rice.

Jan 6, 1922