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By A. W. Gauger

Coal as mined contains varying quantities of inorganic components (mineral matter) which, on combustion, produce the residue known as ash. It has long been realized that the weight of this residue does not equal the weight of the mineral matter originally in the coal, because of the chemical changes that take place during the ashing process. Moreover, the ordinary ash analysis presents the ash as a mixture of oxides with little or no clue to the identity of the mineral species originally present in the coal. It is only for pyritic sulfur that an attempt is made to determine a mineral component. So far as the authors are aware, there are practically no experimental data in the literature as to the percentages of the different mineral species present in coal. The oft-quoted table of Marson and Cobb1 cannot rightly be considered as data, since the authors merely state that the table "shows the probable forms in which these ash constituents exist in coal." In view of the attempts to calculate analyses and determinations of the calorific equivalent of coal to the mineral-matter-free basis, as well as the importance of the mineral species in clinkering, combustion and coking, it seems strange that so few data are available on this phase of coal technology. For example, numerous empirical corrections for use in the scientific classification of coal have been suggested to compensate for the losses from the mineral matter during ignition of the coal to ash. These include multiplication of the ash percentage by various factors such as l 1/10 and 156, the use of the Parr unit coal formula (1.08 A + 22/40 S, where S = total sulfur) as well as certain modifications of the Parr formula that attempt to correct for the organic sulfur present in the coal. Although many experiments have been made to determine the loss on ignition of the clays associated with the coal measures and correction

Jan 1, 1934

By H. E. Nold

ThE raw materials of the ceramic industry are mostly clays. This raw material is ground, water is added and the mixture pugged into a moist, plastic, rather stiff mass. From this mass the desired units of manufacture are made (bricks, hollow building tile, sewer pipe, etc.). These units are dried; then placed in kilns and heated until the desired degree of vitrification is obtained. For firing ceramic ware, two distinct types of kilns are used; namely, periodic and continuous tunnel. Periodic Kilns Periodic kilns are those ordinarily seen in a brick plant. They are either round or rectangular. The raw, dried, formed ware is piled or set in the kilns to depths frequently exceeding 10 ft. The kiln is heated until the ware is matured, then gradually cooled sufficiently to allow men to remove the ware; then the cycle is repeated. The time duration of the cycle may be more than two weeks. In order that heat can be distributed uniformly throughout the pile or setting, the units are placed so as to leave open spaces or flues throughout the pile for the passage of the hot gases. Each kiln is provided with a number of fireboxes (usually 10 or 12) spaced equally in the outside wall. The fireboxes may be equipped with flat or inclined grate bars or they may have no grates at all (dead bottom). Down-draft kilns are most used. In these the hot gaseous products of combustion from the fireboxes are deflected upward by bag walls just inside the fire zone. From the top of the kiln the gases are drawn down through the setting, off through holes in the kiln bottom, and conducted to a stack or stacks. In up-draft kilns the fireboxes are usually set somewhat lower. The hot gases are drawn inward and upward through the ware and pass off from the top. Up-draft kilns find their greatest use in the firing of common brick. In either case the problem is to maintain, as nearly as possible,

Jan 1, 1934

By John Hays Hammond

The Transvaal comprises about 120,000 square miles (nearly • the size of the United States Territory of New Mexico). Besides the famous Witwatersrand, which will here be de scribed in detail, there are two quartz-mining districts of some importance, viz., Lydenburg and De Kaap. The Lydenburg district first attracted attention in 1876, when the alluvial deposits of that section began to be exploited. At a later period vein-rnining was started, and at the present time several companies are operating in that district. The product in 1898 of five companies, running 137 stamps, was 154,560 tons of ore, yielding 108,884 crude ounces of gold (an average of 14.09 dwt. crude gold per ton) valued at £392,378. The De Eaap gold-fields were discovered in 1884. In 1898, seven companies, running 200 stamps, produced 89,760 crude ounces of gold, valued at £314,792. I. Mining Titles in the Transvaal. The mining laws of the Tranuvaal are most excellent in char acter, and while the claims cover every square foot of land for an area of nearly 40 miles long by from 2 to 3- miles wide, there have been practically no conflicts over extra-lateral rights. Notwithstanding the change in the political status of the Transvaal likely to follow the present war, it may be coufi dently assumed that the main features of the mining law of the South African Republic will be retained, and certain op pressive featureu of monopolies, etc., bearing with special weight on the mining industry, will be abolished. The dynamite mo nopoly was one that bore most heavily on the mining industry; and, according to the Reports of the State Mining Engineer, explosives, including fuse and detonators, amounted to nearly 10 per cent. of the total working costs of the mines. Further more, it was impossible to obtain the proper quality for the most economical working, and often 80-per-cent. or 40-per-cent. gelatine had to be used- in many instances where 60-per-cent.

Jan 1, 1902

By L. H. Dushak

DURING the war period of quicksilver activity there were a number of departures from what may be termed the classical quicksilver metallurgy. Attempts were made to beneficiate low-grade ores by gravity concentration and flotation; mechanical furnaces began to replace the Scott furnace and the vertical coarse-ore furnaces, and condensers of sewer tile and redwood tanks were used in place of the older brick and stone condensing chambers. Other developments that have occurred during the current period of quicksilver activity are mainly in the nature of improvement and further refinement of those started during the war period. Each period of quicksilver activity has been accompanied by the proposal of various new processes, including wet methods for the treatment of quicksilver ores and innovations in furnaces, retorts and condenser equipment. As far as the author knows, nothing of economic significance in the way of "new processes" has been developed. There is in fact no real need for any essentially new process for the treatment of quicksilver ores; the direct furnace treatment is simple and inexpensive. Moreover, with rare exceptions, the quicksilver industry has no complex or refractory ore problems corresponding to those which are receiving more and more attention from metallurgists in other branches of the nonferrous field. Under these conditions improvements in quicksilver metallurgy must be looked for through the adaptation of current developments in engineering and metallurgy generally to the particular needs of quicksilver practice rather than through the invention of new processes.

Jan 1, 1930

By Benny J. Nelson

AS a part of the fundamental research program of Aluminum Research Laboratories, some data were obtained on the ternary system Mg-Al-Mn. As very little information on the magnesium corner of this diagram has heretofore been published, it seems desirable to make available the values found for the liquidus and solidus surfaces of this system. Procedure The settling procedure was used for the determination of the liquidus compositions. Metallo-graphic examination of quenched samples, and stress-rupture upon incipient melting, were used for the solidus determinations. The settling procedure has been described in a previous paper.' Briefly, this method involved saturating the alloy with manganese at a temperature substantially above that at which the sohbility was to be determined, then cooling the melt to the latter temperature, and holding it at that temperature for a substantial period of time. Samples for analysis .were carefully ladled from the upper portion of the melt at hourly intervals during the holding period. After the ladling of each sample, the melt was stirred to redistribute some of the manganese that had already settled, because it appeared that when the latter particles of manganese again settled, they aided in carrying down more of the manganese and thus hastened the attainment of equilibrium. The melts were prepared and held in a No. 8 Tercod crucible holding approximately 4 lb of metal. The manganese was added either in the form of a prealloyed ingot (Dow M) containing about 1.5 pct Mn or by the use of a flux (Dow 250) containing manganese chloride. In calculating the flux additions, it was assumed that the manganese introduced would be equal to 22 pct of the total weight of the flux. Temperatures were measured with an iron-constantan thermocouple enclosed in a seamless steel tube, the lower end of which was welded shut. This protection tube also served as a stirring rod. The samples ladled from the upper portions of the melts at the various intervals were analyzed for aluminum, manganese, and iron. When making the alloys which were to be used for the determination of the solidus, 2½ in. diam tilt mold ingots were cast, scalped to 2.0 in. in diam, and extruded into ? in. diam wire. The principal impurities in the melts for this investigation were iron and silicon; their total not exceeding 0.03 pct. Portions of the wire, approximately 2 in. in length, were enclosed in stainless steel capsules for protection from the atmosphere. Bundles of these capsules, with a dummy capsule containing an iron-constantan thermocouple, were heated inside a large steel block (acting as a heat reservoir) in a closed circulating-air type electric furnace. At ap- propriate times, the capsules were removed and quenched in water. The wires were examined metallographically to determine the temperature of initial melting. Short times at temperature were used at the beginning for wire specimens of all alloys to obtain quickly the approximate temperatures at which melting could be first observed. When approximate solidus temperatures had thus been determined, equilibrium heating was attempted. This equilibrium heating consisted of an 8 or 16 hr period at a temperature, about 50 °F below the lowest temperature at which melting occurred when short heating cycles were used, followed by further heating for 1 hr periods at consecutive 10" higher temperatures. The theory for the method of stress-rupture at incipient melting has been well covereda and its limitations are recognized. Thus, if the interfacial tensions are such that the first minute quantity of liquid is "bunched up" at the grain boundary junctions instead of spreading out along the grain boundaries,³ temperatures higher than the solidus are required before melting will be manifested by rupture of the specimen. This point will be elaborated later. Specimens of the wires with a reduced section (approximately 1/16 in. diam) were suspended vertically in a tubular furnace. The setup used is shown in Fig. 1. The clamp holding the specimen was made from alumel thermocouple wire and the thermocouple was thus completed across the specimen by attaching a chrome1 wire to its lower end. Temperatures were read from a Speedomax recorder used in conjunction with a calibrated thermocouple. The small weight attached to the specimen and a vibrator attached to the furnace tube, to aid in distributing the molten constituent along the grain boundaries, were used to bring about rupture at a temperature closely approximating the solidus. The specimens were heated at a rate of about 5°C per min. The rupture of the specimens was indicated both by sound and by the action of the recorder. An argon atmosphere containing a small amount of SO² was used for protection of the specimen. The assembly was taken out of the furnace immediately following rupture and the specimen removed. Some of the broken specimens were examined metallographically and will be referred to later. Results and Discussion Fig. 2 shows a set of typical time-composition curves for liquid samples of the Mg-Al-Mn alloys used for the settling tests. The data as presented

Jan 1, 1952

By C. R. Johnson, R. A. Greenkorn, R. E. Haring

Three confined five-spot miscible displacements at unity, favorable, and unfavorable mobility ratios were conducted in a shallow, water-saturated sandstone of Pennsylvan-ian age near Chandler, Okla. These studies, plus associated laboratory experiments, were designed to measure miscible displacement performance in a controlled natural system, using known scaling criteria to develop an approach to modeling the heterogeneous field system. We have concluded from these studies that: (I) displacement efficiency in the field is a pronounced function of mobility ratio, indicating that miscible fingering observed in simple laboratory models occurs in the field: (2) field displacements can be quantitatively predicted by scaled laboratory models if the degree and location of field permeability variations are preserved in the models: and (3) arbitrary simplifications of heterogeneity will not necessarily predict observed displacement efficiency, and the simpler the model, the more optimistic the prediction. INTRODUCTION Many processes to achieve miscible displacement of reservoir oil by injected fluids have been conceived and field tested by the oil industry. Among the better known are high-pressure gas, enriched gas, and LPG banks. The simplest form of miscible displacement—one fluid miscibly displacing another fluid of different viscosity but the same density—has been studied extensively in homogeneous laboratory models. Observations of unstable fingering have been made which explain the significant decrease in displacement efficiency as the mobility ratio (ratio of displacing fluid mobility to displaced fluid mobility) increases. General industry experience with field tests of miscible displacement projects, mostly LPG banks, has been premature solvent breakthrough and lower than predicted production rate increases. These results have been attributed to either unstable fingering, unusual or unexpected permeability stratification, or both. Miscible displacement data in a controlled natural system have never been reported, however. Also, it has not been shown that properly designed and constructed laboratory models quantitatively predict field-scale behavior. The purpose of the combined field and laboratory ex- periments reported in this paper is twofold. The first was to measure miscible displacement performance at different mobility ratios in natural rock approaching field size under precise, controlled conditions. The second purpose was to utilize known scaling criteria plus several approaches to heterogeneity to model the field. Comparison of model and actual field results should then determine whether or not the laboratory phenomena (manifested by miscible displacement efficiency) are exhibited in large, natural rock systems. We carried out our program by first locating a shallow, water-saturated reservoir whose rock properties were representative of oil-bearing reservoirs. Detailed reservoir description by core analysis and interference testing showed the field site to be heterogeneous. A sequence of controlled, aqueous-phase miscible displacements was conducted at unity, favorable and unfavorable mobility ratios. A central, confined pattern was used to obtain the displacement data. A laboratory program using sand-packed models was conducted to determine the modeling criteria necessary to simulate field behavior of miscible displacement in a heterogeneous system. SCALING THEORY The detailed derivations and descriptions of the scaling laws that apply to laboratory models of reservoirs are adequately described elsewhere, so the following discussion will be restricted to facets of importance in this study. For a displacement in which one liquid miscibly displaces another, the following dimensionless groups are required to have the same numerical value in the model as in the field: The model also must be geometrically similar to the field, be spatially oriented the same as the field (same dip angle), and have the same initial and boundary conditions as the field (same initial fluid saturations and same injection-production well arrangement). When these conditions are satisfied, the theory predicts that at dny dimensionless time (pore volumes of produced fluids) the dimen-sionless flow potential and dimensionless fluid concentrations will be identical at all dimensionless spatial locations within the model and the field. If this prediction is correct, then the local dimensionless velocities must be identical, thus the instantaneous fraction of displaced fluid produced and the cumulative recovery expressed as fraction of original fluids in place must be identical at all dimensionless times. The theory outlined above has been obtained by either dimensional analysis or inspectional analysis of differential

Jan 1, 1966

By R. O. Leach, O. W. Wagner

Because of unfavorable wetting conditions much residual oil is left when a porous material is Pushed by water. Methods suggested to change reservoir wetting to improve oil displncernrnt efficiency are generally expensitlr. The present 1aborator.y study was undertaken to gain an under.standinx of the factors which determine reservoir wettability, arid to find out if oil displacement efficiency might be improved by a wettahility change accomplished at low cost in on oil reservoir. Contact angle measurements were made on mineral surfaces using sevc.r~zl sets of reservoir oil and water samp1es. Results of the contact angle studies suggest that reservoir wetta-hility may he primarily determined by natural surface-active substances present in the reservoir fluids. The effect of changing sa1inity and pH of the water phase was studied. The re.suits suggest that gross changes in preferential wettability might be acc~o~npli.shed by injection of water containing simple chernicnls to alter pH or salinity in the reservoir. Such treatment could he much less expensive than injection of commercial surface-active agents. Waterflood tests have also been made using synthetic cores and oil and water having wening characteristics similar to those of reservoir fluids. Cores initially oil-wet were flooded in such a way that they were made prefermtial1y water-wct by the advancing flood water. This reversal in preferential wettability achieved greater oil displacement efficiency than when either oil-wet or water-wet conditions were maintained throughout the flood. For the systems studied, the higher the oil viscosity the greater the percentage improvement obtained over conventional waterflood recovery. This suggests that a flooding process making use of wettability-reversal may extend the oil viscosity range over which water flooding is attractive. Because a precise adjustment of reservoir wettability does not seem to be required, and because altering the pH or salinity in some reservoirs may be inexpensive, it appears that a waterflooding process employing wet-[ability-reversal could find .succesful field application. I NTRODUCTION The efficiency with which water will displace oil from a porous material is related to the nature of the capillary forces present. These in turn are controlled by the preferential wetting of the solid by the two fluids. Because of unfavorable wetting conditions, 30 per cent or more of the original oil in place may remain unrecovered in that portion of a reservoir flushed by water. This paper is concerned with the possibility of improving waterflood oil displacement efficiency by alterations in the wettability of the porous material. A laboratory study was made to gain a better understanding of the factors which control reservoir wettability, and to determine if the oil displacement efficiency could be improved by some inexpensive means of manipulating wettability of the porous medium. Contact angle measurements were made with several natural and synthetic oil, water and solid systems (1) to obtain a better understanding of how to duplicate reservoir wettability in the laboratory, and (2) to discover possible means for changing preferential wettability of natural reservoir systems. Flooding tests were also made in synthetic systems to determine if oil displacement efficiency could be improved by those wettability manipulations suggested by the contact angle measurements. Based on these studies a possible method for improving waterflood oil displacement efficiency is presented. This method involves causing an originally oil-wet porous material to become preferentially water-wet during the course of a water flood. The purpose of this paper is to present results of the laboratory studies. THEORY Rock surfaces in some oil reservoirs are believed to be covered with a firmly attached bituminous or other organic coating. Such surfaces would be preferentially oil-wet in the presence of both oil and water, regardless of composition of reservoir fluids. Other reservoirs are believed to contain rock surfaces not permanently coated with such materials, and which would be preferentially wet by water in the presence of water and oil free from surface-active substances. However, when the reservoir fluids do contain certain natural surface-active materials in sufficient quantity, rock surfaces acquire a degree of preferential oil wettability caused by adsorption of these natural surface-active materials on the solid. The equilibrium amount of these materials adsorbed per unit surface area is believed to depend upon their concentration in the bulk liquid phases.

By L. B. Herring, Harold Decker

The South Texas area, discussed herein, represents districts 2 and 4 of the Texas Railroad Cominission and extends from Jackson, Lavaca, and Gonzales Counties on the northeast to the Rio Grande River, comprising a total of 26 counties.$ The present boundaries of this district do not coincide with those of earlier reports published in the annual volumes of Petroleum Development and Technology. The war, in its various ramifications, determined and controlled all the phases of the oil and gas industry. Priorities for material and governmental subsidies determined all new operations. New Pools In our opinion, the combine' quantity of crude and distillate reserves added in '943 approached Or possibly exceeded the amount produced. Thirty-five new pools were added to the area' Of these, five have significant reserves and ten offer possibilities of containing consequential reserves. The largest proven reserve discovered during the year was the Slick pool, on the DeWitt-Goliad County line. This is also the most important Wilcox discovery to date in the area. The most significant extension was at Willimar, Willacy County. Other important extensions were developed at Agua Dulce, Seeligson, and Odem. Except for the Porter field, in Karnes County, the Laredo trend, which produces lrom the Jackson and Yegua, proved very disappointing, and this pool is o:C secondary importance. The Scott and Hopper pool, Brooks County, has only orie well, but offers excellent possibilities of becoming an important discovery. It represents at this time the major Frio discovery of the year. The Hobson pool, Karnes County, is not a major reserve, but can be classed as important in that it produces at a shallow depth from the Wilcox. This proves that the potential area of production for this zone occupies a broad trend. Gas and Condensate During the year construction was begun on only one recycling plant, this being in the Sejita field, Duval County. Several others were colltemplated, but no actual operations were begun. The most important development in recycling was the rebuilding of old plants to allow for the fractiona-tion of isopentane, n-butane, isobutane, and propane. Heretofore all pentanes plus have been marketed as cLdistillate,n only a minor portion of the butanes being isolated and sold for fuel purposes. All these new the except propane, are considered vital to the war effort and propane is being marketed as fuel gas. In other instances propane is being isolated and then pumped back into the gas reservoirs for storage. It is anticipated that the demands for this product will increase in the future. Drilling in the Wilcox trend during the year showed the existence of valuable gas

Jan 1, 1944

By L. B. Herring, Harold Decker

The South Texas area, discussed herein, represents districts 2 and 4 of the Texas Railroad Cominission and extends from Jackson, Lavaca, and Gonzales Counties on the northeast to the Rio Grande River, comprising a total of 26 counties.$ The present boundaries of this district do not coincide with those of earlier reports published in the annual volumes of Petroleum Development and Technology. The war, in its various ramifications, determined and controlled all the phases of the oil and gas industry. Priorities for material and governmental subsidies determined all new operations. New Pools In our opinion, the combine' quantity of crude and distillate reserves added in '943 approached Or possibly exceeded the amount produced. Thirty-five new pools were added to the area' Of these, five have significant reserves and ten offer possibilities of containing consequential reserves. The largest proven reserve discovered during the year was the Slick pool, on the DeWitt-Goliad County line. This is also the most important Wilcox discovery to date in the area. The most significant extension was at Willimar, Willacy County. Other important extensions were developed at Agua Dulce, Seeligson, and Odem. Except for the Porter field, in Karnes County, the Laredo trend, which produces lrom the Jackson and Yegua, proved very disappointing, and this pool is o:C secondary importance. The Scott and Hopper pool, Brooks County, has only orie well, but offers excellent possibilities of becoming an important discovery. It represents at this time the major Frio discovery of the year. The Hobson pool, Karnes County, is not a major reserve, but can be classed as important in that it produces at a shallow depth from the Wilcox. This proves that the potential area of production for this zone occupies a broad trend. Gas and Condensate During the year construction was begun on only one recycling plant, this being in the Sejita field, Duval County. Several others were colltemplated, but no actual operations were begun. The most important development in recycling was the rebuilding of old plants to allow for the fractiona-tion of isopentane, n-butane, isobutane, and propane. Heretofore all pentanes plus have been marketed as cLdistillate,n only a minor portion of the butanes being isolated and sold for fuel purposes. All these new the except propane, are considered vital to the war effort and propane is being marketed as fuel gas. In other instances propane is being isolated and then pumped back into the gas reservoirs for storage. It is anticipated that the demands for this product will increase in the future. Drilling in the Wilcox trend during the year showed the existence of valuable gas

Jan 1, 1944

By G. Hileman

At present there are three fields in commercial exploitation in the Argentine. In order of production they are: (1) Comodoro Rivadavia, (2) Salta, (3) Plaza Huincul. Comodoro Rivadavia.—This field is on the coast of the Territory of Chubut in the southern part of the republic. It is being developed and exploited by Yacimientos Petroliferos Fiscales, the government oil entity, and five private companies. The immediate coastal portion of the field, which embraces the original discovery area, is almost completely developed. This is especially true of the original government reserve and one private property. The Y.P.F. has extended its explorations and developments westward to Escalante, 27 km. distant on the state railway. This extension has been the most active and prolific section of the field for the past three years. The government has also continued its exploration drilling in the region lying south of Colonia Sarmiento and east of the Rio Senguer. Private companies have not been able to extend their operations beyond the claims they had in process of acquisition in 1924, when the government reserve areas were established. The Y.P.F. is the major producer of the field and employs modern methods and appliances. Practically all its drilling and pumping operations are electrically operated, from a central power plant. In view of t'he scarcity of water supplies, this facilitates operations and is an economic factor of considerable importance.

Jan 1, 1934

By J. C. Branner

DuriKg the past two or three years I have seen statements regarding the first discovery of fullers' earth in this country that seem to require correction or modification. One appears again in the Mineral Resources of the United States for 1909, part II., p. 738, where it is said that 'fullers' earth was firat discovered in the United States at Quincy, Fla., in 1893." In this connection the following bit of unpublished history concerning fullers' earth in the State of Arkansas is worthy of attention. In April, 1891, when I was State Geologist of Arkansas, a Swede named John Olsen, formerly a copper-miner in Michigan, but then living south of Little Rock, brought me a sample of what he thought mas fullers' earth. He reported that it was from near the town of Alexander, the locality being 1 S. 13 W., section 8, SW. quarter of the SE. quarter. My chemist, Dr. R. N. Brackett, analyzed the material, and reported: Per Cent. Silica,.....SiO2 .... 63.19 Alumina,.... A12O3 .... 18.76 Iron,.....Fe2O3 .... 7.05 Lime,.,...CaO .... 0.78 Magnesia,.... MgO .... 1.68 Potash,.... K2O ,... 0.21 Soda,.....Na2O .... 1.50 Loss on ignition,........7.57 100.74 Water at 110° to 115° C. = 7.84. Another sample from about the same locality, also brought by John Olsen, on analysis by Dr. Brackett gave :

Jan 1, 1913

By G. Sachs, E. J. Ripling, S. I. Liu, J. J. Lynch

INTRODUCTION IT is a generally recognized fact that by repeated straining the fracture stress of any metal is reduced to a fraction of its value for static loading. The value of this fatigue strength depends upon numerous factors, such as the states of strain and stress, the limits of straining, and the number of repeated loadings or cycles.1.2,3 The large volume of previous investigations on fatigue is concerned entirely with large numbers of cycles, say exceeding 10,000 and up to 500,000,000. However, the changes in fracture stress and fracture strain occurring after a small number of repeated loadings have attracted little attention. Apparently the only investigations of this type are those byLudwik4,5 who subjected steel, copper, and aluminum wire to repeated torsion. In each test the torque was varied between identical values in the two directions of twisting. Depending upon the magnitude of the moment, fracturing occurred after a number of cycles, up to 10,000. The results of Ludwik's tests will be discussed later. Such torsion does not readily yield actual stress and strain values. Therefore a preliminary study was made of the effects of repeated direct stresses, i.e., tension and compression stresses. Because such tests are considerably more tedious than torsion tests, only high stresses were used in the preliminary work, yielding definite changes in metal properties after a few cycles. It was found in these tests that strains could be controlled more readily than stresses in the investigated range of high stresses. This paper, consequently, deals with the effects of strains of equal magnitude but different signs. The metal was first prestrained in static tension by a certain amount then subjected to compression to yield the same amount of strain after unloading. This loading cycle was repeated up to a maximum of seven times. After various cycles, the stress-strain curves in tension were determined, up to fracturing. As material for these tests, the aluminum alloy 24ST was selected because it exhibits a comparatively small amount of necking in the tension test. This alloy permitted, therefore, rather accurate control at the high strains necessary to produce fatigue failures at less than seven cycles. The results of this investigation appear sufficiently interesting to extend the method of attack in various directions. It is intended to study (I) the effects of cycles up to a few thousands and (2) the effects of strains of different magnitude in tension and compression, respectively. The latter variable also includes as a special case the effects of compressive strains.

Jan 1, 1948

By John T. Galey

In all, 210 wellst were completed in southwestern Pennsylvania during 1939, which is 59 more than were drilled during the preceding year. Of this number, 137 were gas wells, which is a considerable increase from the 81 completed during 1938. Only 25 oil wells were completed, as against 28 in the previous year, and 28 dry holes, 6 more than last year. Shallow Development—Gas The increase in the number of gas wells is largely the result of a search for additional gas in Armstrong and Indiana Counties. Although a considerable number of wells were drilled in the latter county, the majority of them produced less than 100 M cu. ft. initial open flow. In Armstrong County, a new pool was opened in Cowanshannock township, producing from the third Bradford sand. Several large wells were obtained there, one of which produced an initial of nearly 12 million cu. ft., with a reservoir pressure of 1100 Ib. However, the productive area has been fairly well outlined by further drilling and shows that the pool covers only about 800 acres. The sand is 20 to 30 ft. thick, and probably has 5 to 6 ft. of pay. Thus this reserve is not an important one. Several wells were found in Menallen township, Fayette County, where the Big Injun sand has been having a play for the past three years, but the activity there is much less than a year ago. Oil On the west side of the Bradford sand gas pool, Cowanshannock township, Armstrong County, a well was drilled which flowed 100 bbl. the first day from the Tiona sand. The probability is that this well is a freak, as the Tiona has been drilled within a fairly close distance on every

Jan 1, 1940

By C. A. Wert

THE solid solubility of cementite in a-iron has been investigated a number of times and there is now general agreement on the solubility of about 0.018 wt pct at the eutectoid temperature, 720°C. With decreasing temperature, the solubility falls off so rapidly and to such a low value that no data obtained by standard metallurgical methods are available below 500°C. Using a new technique, however, Dijkstral has obtained apparently accurate solubilities down to 400°C; which data agree well with previously measured solubilities in the 600" to 700°C temperature range.' The present paper has in part the purpose of extending his work to still lower temperatures. Earlier work of Low and Gensamer3 on iron has established that the presence of a relatively small amount of carbon can play a tremendous role in affecting the mechanical properties. In particular they found that the yield point remained high as they reduced the amount of carbon in the iron; the yield point dropped only after the carbon content had fallen to something less than 0.003 wt pct, the point where their carbon analysis failed. It seemed desirable to the present author to see if some means could not be found to extend this part of their work. This investigation has then the additional purpose to determine the range of carbon concentration in which the major change occurs. Solubility The method used in the present work to measure small percentages of carbon in a-iron utilizes internal friction. Since this method may not be fa-miliar to the reader, the following explanation will be given (a part of this procedure is from unpublished results of Dijkstra): It is known that the internal friction associated with the diffusion of

Jan 1, 1951

By Richard Pearce

IN looking around me for some subject on which to frame an address for this meeting, it has occurred to me that some results of observation and investigation, in regard to the varied conditions under which gold is found, may possibly prove of interest. The subject is one which frequently crops up in discussions at our meetings, but there is always an immense amount of uncertainty expressed as to the actual condition in which the gold exists in any particular ore. It follows, therefore, that any light which might be shed on this rather complex subject, would be of value to science and of service to mining and metallurgical practice. In some investigations which I have, from time to time, been led to make, for the purpose of determining to what extent an ore might be concentrated, I have been astonished at the very varied and apparently inexplicable results encountered, and have been naturally led to inquire into the causes for such seeming inconsistency. The mines of Gilpin county, Colorado, where gold was first discovered in that State, furnish an infinite variety of examples of its occurrence, and it was here that difficulties first presented themselves to the Colorado miners, in the sudden transition from what is called " free-milling gold-ore " to an ore characterized by properties which make the ordinary treatment by amalgamation stamp-mills utterly impracticable. So long as mining was limited to what might be called the zone of oxidation in the veins, just so long might amalgamation be conducted without difficulty; but directly the miner reached a point beyond the influence of the oxidizing power of the surface waters, the gold resisted all attempts at amalgamation, and recourse • was had to smelting.

Jan 1, 1890

By Murray F. Hawkins

One problem of reservoir engineering is the early estimation of the size of newly discovered reservoirs. Often these reservoirs are the expansion type in which sizeable pressure drops occur incident to the production of small fractions of the oil reserve, above the bubble point, and a material balance equation may be solved to find the reserve. The early form of this equation' considered only the compressibility of the oil. Later Hall2 showed that the compressible nature of the formation rock is a significant factor in production above the bubble point, and he presented a new equation which includes a formation (rock) compressibility term. This note presents a further extension of the material balance equation as applied to volumetric, unsat-urated reservoirs above the bubble point by including a term for the presence and compressible nature of the interstitial water. DERIVATION OF EQUATION During a decline in average reservoir pressure, ?p ?p, — p1 the initial reservoir volume V,, will decrease to some value V, due to the reduction in pore volume as a result of a decline in the hydrostatic pressure within the formation, and v, = V,, [l — cr ?p]......(1) The formation compressibility c, is expressed in terms of change in pore volume per unit pore volume per psi. Simultaneously the connate water within the formation expands from an original volume V,, = S,V,, to a new volume V,, V, = s,v,, [I + c,npl.....(2) The difference [Vp — V,] is the hydrocarbon pore volume at pressure p and may be equated to the volume of the remaining oil, or [N — N,] B, = V,,, [I - C~A;] - S,.Vpi [l + cwnjl.........(3) But the initial oil in place in terms of the initial reservoir volume, connate water, and formation volume factor is Ilividing Equation 3 by Equation 4 eliminates V,, to give,

Jan 1, 1956

By John T. Galey

In all, 210 wellst were completed in southwestern Pennsylvania during 1939, which is 59 more than were drilled during the preceding year. Of this number, 137 were gas wells, which is a considerable increase from the 81 completed during 1938. Only 25 oil wells were completed, as against 28 in the previous year, and 28 dry holes, 6 more than last year. Shallow Development—Gas The increase in the number of gas wells is largely the result of a search for additional gas in Armstrong and Indiana Counties. Although a considerable number of wells were drilled in the latter county, the majority of them produced less than 100 M cu. ft. initial open flow. In Armstrong County, a new pool was opened in Cowanshannock township, producing from the third Bradford sand. Several large wells were obtained there, one of which produced an initial of nearly 12 million cu. ft., with a reservoir pressure of 1100 Ib. However, the productive area has been fairly well outlined by further drilling and shows that the pool covers only about 800 acres. The sand is 20 to 30 ft. thick, and probably has 5 to 6 ft. of pay. Thus this reserve is not an important one. Several wells were found in Menallen township, Fayette County, where the Big Injun sand has been having a play for the past three years, but the activity there is much less than a year ago. Oil On the west side of the Bradford sand gas pool, Cowanshannock township, Armstrong County, a well was drilled which flowed 100 bbl. the first day from the Tiona sand. The probability is that this well is a freak, as the Tiona has been drilled within a fairly close distance on every

Jan 1, 1940

By John T. Norton, V.G. Mooradian

The diffusion of metal atoms into the crystal lattice of another metal and the assumption of regular positions to form a homogeneous alloy are some of the most fundamental phenomena of structural metallurgy. The mechanism of this process has been the subject of a great deal of study from many viewpoints, but the picture is still far from complete. It is generally believed that if one metal is to diffuse into another, the first must have some solubility in the second1. This means that the solvent must be able to accommodate the stranger atoms, either on points of its own lattice or in the interstices between, without losing its own crystal-lographic identity. It is also a general observation that cold-working is a distinct aid in the diffusion process, causing it to take place with greater rapidity at the same temperature or with the same speed at a lower temperature. There is considerable doubt, however, as to the real significance of the deformation in its effect on the diffusion mechanism. Several factors associated with the cold-working may be responsible for the increased diffusion rate. The plastic deformation causes a distortion of the solvent lattice, which may be an aid in the assimulation of atoms of another kind. There are many references2 in the literature that suggest that some distortion or "loosening" of the lattice is necessary for atomic migration and that diffusion cannot take place in the undis-torted lattice. On the other hand, it may be that the cold-working causes an increase in surface of contact between the two metals through fragmentation or provides a more intimate contact that is necessary for diffusion. If it is true that lattice distortion is an important factor in diffusion, it seems as if there should be some particular relation between

Jan 1, 1935

By G. C. Gould

The nature of freckle segregation is determined by chemical analyses, microradiograplzy, and electron microprobe. In addition, the influence of chemistry variation on freckle formation is studied in laboratory experiments. It is demonstrated that controlled laboratory solidification can produce freckle segregation. "FRECKLE" segregation is a discontinuous, rod-like segregation observed in vacuum consumable -electrode ingots. Figs. 1 and 2 show this segregation as pencil-like, dark etching areas of segregation found in longitudinally and transversely sectioned consumable-electrode ingots. In most cases the segregation is perpendicular with respect to gravity and parallel to the longitudinal axis of the ingot. The segregation is most often encountered at or around midradius in large vacuum consumable-electrode ingots. The austenitic alloys, A-286* and 718, † have shown particular susceptibility to this mode of segregation. The origin of these rodlike pockets of segregation is not well-understood. It has been suggested that the segregation is a result of a portion of the electrode dropping off and passing through the arc un-melted. On the other hand, smeltzer1 has demonstrated the freckle segregation in A-286 to be comprised of low-melting constituents relative to the matrix melting point. The discontinuous nature of the segregation is the most perplexing facet of the freckle-segregation problem. It was to gain some insight into this part of the problem that this work was undertaken. I) PROCEDURE At the outset of the work identification of the phases present and the elements concentrated in the freckle areas was undertaken. The electron micro-probe was used to determine general enrichment as well as -specific phase chemistry. Microradiography using cobalt and chromium radiation was also used on the freckle areas again to determine the elements involved in the segregation. X-ray diffraction patterns were made from portions of these same foil specimens. Optical microscopy and Knoop hardness measurements were also used

Jan 1, 1965

By V. G. Mooradian, John T. Norton

The diffusion of metal atoms into the crystal lattice of another metal and the assumption of regular positions to form a homogeneous alloy are some of the most fundamental phenomena of structural metallurgy. The mechanism of this process has been the subject of a great deal of study from many viewpoints, but the picture is still far from complete. It is generally believed that if one metal is to diffuse into another, the first must have some solubility in the second1. This means that the solvent must be able to accommodate the stranger atoms, either on points of its own lattice or in the interstices between, without losing its own crystal-lographic identity. It is also a general observation that cold-working is a distinct aid in the diffusion process, causing it to take place with greater rapidity at the same temperature or with the same speed at a lower temperature. There is considerable doubt, however, as to the real significance of the deformation in its effect on the diffusion mechanism. Several factors associated with the cold-working may be responsible for the increased diffusion rate. The plastic deformation causes a distortion of the solvent lattice, which may be an aid in the assimulation of atoms of another kind. There are many references2 in the literature that suggest that some distortion or "loosening" of the lattice is necessary for atomic migration and that diffusion cannot take place in the undis-torted lattice. On the other hand, it may be that the cold-working causes an increase in surface of contact between the two metals through fragmentation or provides a more intimate contact that is necessary for diffusion. If it is true that lattice distortion is an important factor in diffusion, it seems as if there should be some particular relation between

Jan 1, 1935