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By J. P. Heller

The purpose of this discussion is to comment briefly on one of the points raised in the paper. The topic is that referred to in the Conclusion 2, in which the authors note a "disproportionate increase in mixing rate" as they proceed from a displacement performed at viscosity ratio 0.998 to one at 1.002. The recovery curve of this displacement, Fig.2A, shows a quite noticeable difference between the two runs in which displaced and displacing liquids were interchanged. This difference is ascribed by the authors to the change in viscosity ratio between the two experiments. This interpretation of the experimental results must certainly be based on rather precise measurements of the fluid viscosities or, at least, of the ratio of their viscosities. The ordinary Ostwald viscometer, employed in the usual way, is only just able to distinguish between liquids whose viscosities differ by two or three parts per thousand. The experimental refinements which then must have been necessary to measure with any precision a viscosity ratio of 1.002 would be worthy of mention. Indeed, one would have expected the authors to devote at least a paragraph to the display of this technique. For the same reason - to emphasize that the details of such unusually critical experimental work should be reported and discussed in the literature — I would have liked to see some comment by the authors on the requirements for temperature control during both the viscosity measurements and the displacement experiments. The temperature coefficient of viscosity of Soltrol C at room temperature has been measured in this laboratory at about - 1.9%/1°C. How much did the coefficients for the fluid mixtures used in the experiment differ from this and from each other Even if the two fluids were identical in this respect, it would appear that a temperature difference of .l°C between them in the flow system would produce a viscosity con- trast equal to that imposed by their composition. Reference to the experimental solutions of these problems would render Conclusion 2 more credible. Published theoretical work on the stability problem contains no indication of such extreme sensitivity to the viscosity ratio in the immediate neighborhood of unity. On the contrary, perturbation calculations such as those made by Chuoke1 and Perrine2 lead to initial finger growth rates proportional to the first power of the viscosity difference. The later instability growth calculated by Scheidegger,3 using the assumption of zero pressure gradient perpendicular to the average flow, is also simply proportional to the viscosity difference. The conflict regarding the sensitivity of the dependence of instability growth or mixing rate on the viscosity contrast needs explicit recognition in the literature. In particular, it would seem that the experimental work reported here should be supported by a more detailed description of the viscosity controls. Further discussion of possible alternative interpretations of the data would also be in order. For instance, is it possible that the unconsolidstted bead pack used changed its characteristics between the runs (due, perhaps, to the handling and inverting involved in the injection of the front) Or, are the data points of Fig. 2A averages from several runs performed in a series in which the two liquids alternated as displaced and displacing fluids? To summarize, it seems to me that the relationship asserted by Conclusion 2 in the paper needs the support of more detailed experimental evidence. REFERENCES 1. Chouke, R. L., van Mews, P. and van der Poel, C.: "The Instability of Slow Immiscible Viscous Liquid-Liquid Displacements in Porous Media", Trans., AIME (1959) Vol. 216, 188.

By O. J. Neslage, R. W. Jenkins

MINE operators today are paying increased attention to the mechanization of drilling operations as an important factor in increasing efficiency and decreasing costs. Recent progress in the design of drill jibs for mounting on drill carriages, or jumbos, has done much to advance the mechanization of mining methods. This progress has introduced new opportunities in the application of "jib jumbos" that are worth serious consideration. An attempt will be made here to classify the various types of jumbos and drill mountings available for level development and flat stope work, t6 indicate applications, and to measure their effectiveness in relation to their cost. The data here are based on a wide variety of field usage, and are offered only to point up, in a general way, the relative efficiency in proportion to cost. It should be remembered that any contemplated jumbo installation must be studied to determine what type of installation is most suitable, considering ground conditions, loading, timbering and haulage equipment, service available, and attitude of manpower. Early Drill Carriages: The advantages of some sort of a drill carriage were recognized at the time rock drills were introduced. In drift or heading operations where a fairly standard drill round and cross section were anticipated, as well as in flat bedded deposits where standard slabbing rounds were used, track and crawler-mounted drills found an early application. These first drill jumbos were little more than drill carriers, designed locally and manufactured with materials at hand. Of comparatively simple construction, function, and low capital cost, they usually consisted of a hinged column which supported one or more drills on arms or universal bars. When the column was pivoted vertically, the drills were moved into position. Screw jack extensions reached from the column to the roof and floor to hold the drill rigid. In some cases, particularly in tunnel jumbos, enough weight was carried that rail clamps or roof jacks were sufficient. Many of these column and arm-type jumbos, usually equipped with air and water manifolds, steel racks, and staging for drillers, are still in use today. Some have employed air or hydraulic extensions for securing the columns. They offer the equip-saving advantage of having all the necessary out, ment together, and they un be moved i and t. set up and torn down as a unit. Boom-type Jumbos: When the advantages of to column-type jumbo were seen, operators could to realize the further gains possible. More time could be saved with mechanical assistance to position api drill vertically. A rack on the column and a pinion on the arm for raising and lowering the drill in the manner of a quarry bar were tried with some success. The most outstanding solution to the vertical handling problem was reached with the boom-type of jumbo. Here two or more machines were mounted on a cross arm at the end of a boom that was pivoted at the rear of the track. This was raised and lowered by various mechanical aids. Occasionally air or hydraulic power was used. Nearly all of today's wagon drills use this boom-type principle. Boom jumbos represent a savings in time and physical effort expended in raising and lowering the drills. The boom must be balanced by the roof of the truck which is secured by rail clamps or type jacks. The most successful application of areawhere this of jumbo has been in the Tri-State area where multiple long-feed machines are used on caterpillar-mounted, boom-type jumbos for slabbing

Jan 1, 1951

By R. W. Jenkins, O. J. Neslage

MINE operators today are paying increased attention to the mechanization of drilling operations as an important factor in increasing efficiency and decreasing costs. Recent progress in the design of drill jibs for mounting on drill carriages, or jumbos, has done much to advance the mechanization of mining methods. This progress has introduced new opportunities in the application of "jib jumbos" that are worth serious consideration. An attempt will be made here to classify the various types of jumbos and drill mountings available for level development and flat stope work, t6 indicate applications, and to measure their effectiveness in relation to their cost. The data here are based on a wide variety of field usage, and are offered only to point up, in a general way, the relative efficiency in proportion to cost. It should be remembered that any contemplated jumbo installation must be studied to determine what type of installation is most suitable, considering ground conditions, loading, timbering and haulage equipment, service available, and attitude of manpower. Early Drill Carriages: The advantages of some sort of a drill carriage were recognized at the time rock drills were introduced. In drift or heading operations where a fairly standard drill round and cross section were anticipated, as well as in flat bedded deposits where standard slabbing rounds were used, track and crawler-mounted drills found an early application. These first drill jumbos were little more than drill carriers, designed locally and manufactured with materials at hand. Of comparatively simple construction, function, and low capital cost, they usually consisted of a hinged column which supported one or more drills on arms or universal bars. When the column was pivoted vertically, the drills were moved into position. Screw jack extensions reached from the column to the roof and floor to hold the drill rigid. In some cases, particularly in tunnel jumbos, enough weight was carried that rail clamps or roof jacks were sufficient. Many of these column and arm-type jumbos, usually equipped with air and water manifolds, steel racks, and staging for drillers, are still in use today. Some have employed air or hydraulic extensions for securing the columns. They offer the equip-saving advantage of having all the necessary out, ment together, and they un be moved i and t. set up and torn down as a unit. Boom-type Jumbos: When the advantages of to column-type jumbo were seen, operators could to realize the further gains possible. More time could be saved with mechanical assistance to position api drill vertically. A rack on the column and a pinion on the arm for raising and lowering the drill in the manner of a quarry bar were tried with some success. The most outstanding solution to the vertical handling problem was reached with the boom-type of jumbo. Here two or more machines were mounted on a cross arm at the end of a boom that was pivoted at the rear of the track. This was raised and lowered by various mechanical aids. Occasionally air or hydraulic power was used. Nearly all of today's wagon drills use this boom-type principle. Boom jumbos represent a savings in time and physical effort expended in raising and lowering the drills. The boom must be balanced by the roof of the truck which is secured by rail clamps or type jacks. The most successful application of areawhere this of jumbo has been in the Tri-State area where multiple long-feed machines are used on caterpillar-mounted, boom-type jumbos for slabbing

Jan 1, 1951

By S. M. Brisbane

THE life of refractory linings in rotary cement kilns can be shortened by uneven or inadequate support of the kiln and its shell and by variations in the conditions of operation. Alteration of these factors may, according to their nature, bring about mechanical deterioration of the lining or promote chemical attack. Chemical attack has been described elsewhere.1-4 The distortion of cement kilns has been discussed in a general manner by Rochow,6 ho indicates the amount of distortion which may occur in an unlined shell, and by Rosenblad: who states that the deformations of the shell are greatest above the trunnions. The present article indicates the extent of the distortion of a kiln to an oval shape in certain selected positions and the deviation from a straight line of the kiln along its length between two supports. The cement kiln is a long, hollow, rotating cylinder consisting of steel plates which may be either welded or riveted together. This shell is supported on tires, frequently 60 ft apart, which roll on trunnions. The large mass of the kiln causes distortion of its cross-section; it becomes slightly oval, i.e., diameters lengthen as they become horizontal and shorten as they become vertical. There is also a tendency for the shell to bow between supporting tires; this bowing may be upwards or downwards depending on the position of the weight forces and the supports. The extent of the deviations from the ideal kiln shape was investigated. Observations described in this paper were made on the shell of the clinkering zone between the first and second tires of two of the kilns at the Geelong works of Australian Portland Cement Pty. Ltd. The kilns were both 400 ft long and 10 ft diam with a welded enlarged burning zone 11 ft 6 in. diam. The shell was fabricated from mild steel and in this section its thickness was 1 in. It was lined with 41/2 in. of chemically bonded magnesite-chrome bricks which were jointed with mild steel plates. The kilns operate on a 4 pct slope and the speed may be varied between 0.75 and 1.68 rpm. The wet process is used; kilns are coal fired and are fitted with integral coolers. Temperatures within the kiln are difficult to determine with any accuracy because of the absence of black body conditions, but surface temperatures are probably in the range 1420° to 1470°C. Average shell .temperatures at the two positions at which the deformation studies were made were 370°C and 355"C respectively. Methods: In determining the ellipticity it was necessary to measure the lengths of the vertical and horizontal diameters while the kiln was in operation; data obtained from a stationary kiln would not have the same practical significance. For this purpose the four points V, W, X, and Y at the ends of two mutually perpendicular diameters were marked on one kiln. The point X is shown in Fig. 1. For the measurement of the length of the vertical diameter a vertical column, to which a horizontally aligned telescope was attached, was placed 10 ft from the kiln. The telescope could be racked up and down in a vertical plane. Two sets of readings were taken, one set when each of the points V, W, X, and Y was at its maximum height above the

Jan 1, 1957

By G. Thodos, R. J. Smialek

A method has been developed that permits the correlations of Mehra and Thodos8 and Dastur and thodos2 for binary systems to be used for the prediction of the vapor-liquid equilibrium constants of the light and heavy constituents, Kland Kh, of a ternary hydrocarbon mixture. Furthermore, the unique relationship observed in this study, i.e., a plot of log Ke/Ki vs log Kp/K h is linear and passes through the origin, permits the calculation of the K-value for the intermediate component. This approach has been used to establish K-values for the constituents of the three ternary hydrocarbon systems used to develop this method and has also been applied to two additional ternary hydrocarbon systems to yield an average deviation of 7.7 per cent resulting from a total of 294 points for the five ternary systems considered. INTRODUCTION The rigorous calculation of vapor-liquid equilibrium constants for systems containing two or more components is a difficult problem and becomes extremely complex at elevated pressures and for conditions approaching the critical point. Although thermodynamic relationships can be developed to account for the vapor-liquid equilibrium behavior of simple systems, their use is limited because the necessary PVT data for these systems are not generally available. To establish a method for calculating K constants directly, without any recourse to the PVT behavior of a system, Mehra and Thodos8 applied the principle of corresponding states to the vapor-liquid equilibrium constants of binary hydrocarbon systems. They developed a series of charts which made possible the prediction of K-values for all binary hydrocarbon systems not containing methane. This work has been extended by Dastur and Thodos2 to include binary hydrocarbon systems containing methane. The charts developed in these two studies cover the high-pressure region and are applicable to conditions in the vicinity of the critical point. The ability of this approach to predict vapor-liquid equilibrium constants of binary hydrocarbon systems suggests that this method may be extended to the prediction of the K-values of the components of ternary hydrocarbon systems. In this investigation, the charts developed for both the methane and non - methane binary systems,2,8 together with mixture rules developed in this study, have been used to predict the K-values of the light and heavy components of a ternary hydrocarbon system. These calculated values are then used to establish the K-value of the intermediate component through the use of a novel relationship developed in the present study. DEVELOPMENT OF METHOD FOR PREDICTING K-VALUES OF TERNARY SYSTEMS The application of the corresponding state charts developed for binary hydrocarbon systems is restricted to those systems containing two components. The extension of these correlations to three-component systems requires that the ternary system be reduced to an equivalent binary, which can be treated in a manner consistent with the corresponding state development. To establish such an approach, the vapor-liquid equilibrium constant of the light component K is first calculated by assuming that the ternary mixture consists of the light component and a pseudo-heavy component of the intermediate and heavy constituents of the original ternary. To establish the vapor-liquid equilibrium constant of the heavy component Kh, the light and intermediate constituents of the ternary are combined to form a pseudo-light component of another equivalent binary system. The calculated values Kl and Kb are then utilized to calculate the vapor-liquid equilibrium constant of the intermediate component EQUILIBRIUM CONSTANT FOR LIGHT COMPONENT K To calculate the K value of the light (most

Jan 1, 1965

By Gerald C. Mathis

FERGUS County, Mont., shown in Fig. 1, is known for its once famous gold mines near the old towns of Gilt Edge, Maiden, and Kendall. But at Heath, a small farming community near the foothills of the Snowy Mountains, thousands of tons of gypsum have been mined since 1916. The value of the gold taken from the mines of Fergus County runs into millions of dollars; the value of the products made from the gypsum of the Heath mine is also in the millions. The gypsum mine will continue to produce for many years, while the gold mines are closed today. The Heath gypsum mine was developed by the Northwest Gypsum Co. in 1916. The products of the small mill built by this company were plaster, agricultural gypsum, and raw gypsum for cement manufacturing. The United States Gypsum Co. prospected the adjacent property in 1916 and 1917 by means of two adits and some exploration drill holes. During World War I, the company abandoned operations at Heath, but again became active in this area in 1928 hen it purchased all the property of the Northwest Gypsum Co. A long range program of expansion was begun with the building of a block plant and the purchase of additional land and mineral rights. A modern wall board plant was built in 1936. When the old wooden mill purchased from the Northwest Gypsum Co. burned in 1937, an all-metal calcining plant located at Blue Rapids, Kansas, was dismantled, moved to Heath, and erected on the site of the mill. In August 1951 a new mine was opened 3000 ft north of the mill. Rock is conveyed from the mine to the mill by an 18-in. belt conveyor. The Heath gypsum deposit lies at the base of the Ellis formation of Jurassic Age. The Ellis at Heath lies unconformably on the black fissle shale of the Heath formation of the Big Snowy Group, which is Mississippian in age. The strike of the gypsum bed is N45°E and the dip approximately 3" NW; the regional strike and dip of the area. The gypsum lies in a series of six layers separated from each other by thin seams of shale. The lower layer is composed of' gypsum and shale intermingled and is not of commercial grade. The upper five layers are high in purity, but only the middle four layers are mined on the advance, as the top layer is left for roof support. This top layer is mined on retreating operations at the same time the pillars are robbed. Total thickness of the gypsum layers varies from 12 to 14 ft. Fig. 2 shows the average thickness and arrangement of the layers. Mining Methods The mine was originally developed by driving an adit into the gypsum horizon. The Northwest Gypsum Co. mined in the top four layers, the top layer being split, leaving about 12 in. for roof support. A modified room and pillar method was used: entries were 15 ft wide and rooms varied between 20 and 30 ft and were turned on 90" from the entries. Crosscuts between the rooms left pillars from 10 to 20 ft square. The rock was loaded by hand into 1-ton mine cars and pulled to a central gathering point by mules; from the gathering point, mules or horses were used to pull the string of cars to the mill tipple. This method was continued by the United States Gypsum Co. from 1928 to 1937.

Jan 1, 1954

By Georges Caraghiaur

INTRODUCTION A small, independent mining enterprise (SIME) is an independently owned and operated business concern engaged primarily in mineral development, from the exploration to the production stage. By definition, a SIME is not dominant in its field and has no long-term financial backing. It is not a major producer of minerals, nor is it a petroleum company, a government organization or a subsidiary of such organizations. A SIME may or may not be listed on stock exchanges. The SIME is also called small miner, junior mining company, speculative mining company, and penny-stock mining company. The survival and growth of a SIME is most often controlled by an independently minded entrepreneur, who not only conceives and carries out new projects, but is materially affected by the success or failure of these projects. Usually, a SIME does not have a large or constant cash flow. Such a lack of long-term financial backing forces the SIME to meet the challenge of finding capital for its activities on a step-by-step basis. Its survival strategy is thus based on finding funds at the right time, of the right type and in the right quantities. The purpose of this paper is to show that the type of venture in which a SIME is involved affects the difficulty of raising new capital and the choice of possible sources of funds. The Small, Independent Mining Enterprise (SIME) The SIME is not a figment of the imagination of financial speculators. In Canada, there are more than 1,800 small mineral enterprises which spend on the average less than $1,000,000 per year on activity which is directed at bringing forth new mineral supply. In the United States, 64% of the non-fuel mining operations are conducted by nine or fewer men, and the coal industry is characterized by several thousand smaller independent producers, still predominantly family owned or controlled. In Chile, 80% of the mines can be classified as small mines. In the Philippines, approximately 60% of metal mining operations are classified as small mines. The SIME is actively engaged in mining all over the world, and very much so in the Pacific Rim. The Mineral Supply Process The whole process of bringing forth new mineral supply involves a dynamic sequence of activities, ranging from the initial exploration for a mineral occurrence to the production of a marketable product. A typical sequence is outlined in Figure 1. At the grass-roots exploration stage, a series of geological, geophysical and geochemical tests is aimed at locating a mineral occurrence. Especially in the early phases of such activities, the uncertainty (risk) surrounding a venture is high, since only general geological information exists on which to base a judgement of the economic viability of the venture. Such risk is attractive to few investors. As the information-gathering process continues, uncertainty diminishes. Once exploration efforts result in the discovery of a mineral occurrence, i.e. when indications of mineralization and mineable widths are obtained by drilling, there is still uncertainty concerning the extent of mineralization and the probability of having located an economic mineral deposit. The expected return on investment at such a stage may well be negative but the slight possibility of a very high positive return will make a number of financial sources available to an exploration company. At the development stage, much of the uncertainty

Jan 1, 1985

By Lane Mitchell

A ceramic product or processed material is a solid composed of materials which have been subjected to heat above 468.3°C (875°F). The raw materials, which are blended together (or in some cases used singly), are selected and utilized for various reasons such as ease of fabrication, aid to processing, to yield desired properties after processing, lack or controllable degree of toxicity or hazard, availability, cost, and perhaps other considerations. Almost all solid inorganic, some organic, and some liquid and gaseous materials have the potential to be used individually in some ceramic product. There are several fundamental functions to be fulfilled in every ceramic product and a number of secondary functions are desirable in specified products. These functions are generally met by the most widely occurring minerals and rocks of the earth and their debris. This fact characterizes ceramics as a field utilizing the raw materials most available to man. Of course, specified products utilize synthetics, organics, and rare inorganics to produce desired results. Any solid nonmetallic product processed by subjection to temperature above a red heat may be called a ceramic product. Widely used construction materials and units, domestic utensils and units, industrial parts to facilitate manufacture, technical components, and aesthetic creations are very often of a ceramic nature because of their durability, inertness, hardness, ease of fabrication, cost, and availability of the ingredients. Often, organics or metals cannot meet desired specifications for some of these products. The rocks and minerals and mineral debris of the earth are largely siliceous. Oxygen and silicon comprise roughly 75% of the earth's crust with aluminum, iron, calcium, and the alkalies following in abundance. Silica (SiO2) and silicates can be melted to form glasses. Alumina (A1203), present in a mineral compound, gives greater durability, hardness, and strength, but lessens the glass-forming property. Iron, calcium, and the other alkalies flux silica and reduce melting points. Thus sand, which is generally almost pure SiO2, and clay, which is generally hydrated alumina silicate, are the most widely used of all ceramic raw materials-principally because of the glass-forming propensities of silicates. In ceramic formulations, clay is generally a refractory filler or skeletal material, having in the raw state a plasticity derived from its colloidal grain size and its water-loving nature. On the other hand, silica sand is a glass former or nonplastic filler. Clay and silica sand in pure forms are quite refractory, i.e., not easily melted. Clay, although siliceous, is less of a glass former than pure silica and is more refractory. Natural contaminants, such as iron oxide or limestone, adulterate many clays and some sands. These contaminants act as fluxes and reduce the fusion points of the mineral or blends. Glass is made from silica sand by fluxing the sand with strong bases, usually soda ash and limestone. Red building bricks are hard and durable because the sand and clay have been partially fused with help of natural iron oxide serving as a flux. The iron oxide performs a dual function, serving as a pigment as well as a flux. In a blend of clay and sand and iron oxide, the sand is more susceptible to fusion than is the clay. Although silica sand and clay are the most widely used raw materials in most ceramic products, many other minerals, and some nonminerals are utilized in products where these materials can produce or aid in achieving desired results. Limestone and dolomite, feldspars, pigmentary minerals, refractory oxides or carbides, and special property producers can

Jan 1, 1983

By Julian Szekely

Through the simultaneous statement of Maxwell's equations. the turbulent Navier-Stokes equations and the differential thermal energy balance equation, a mathematical representation has been developed for heat transfer and fluid flow in electric arc furnaces. In broad outline the theoretical predictions appear to be consistent with experimental measurements. A discussion is presented of the general arc furnace control and optimization problem, together with the potential for the incorporation of the mathematical model given in the paper, into future control and optimization schemes. ELECTRIC ARC FURNACE STEELMAKING accounts for about 24% of the total steel produced in the U.S., consuming about 550kw-hr/ton of steel which amounts to about 1.4x1010 kw-hr annually. The percentage of steel produced by the electric arc furnace route has doubled since 1960 and is expected to increase further in the foreseeable future, particularly with the more extensive use of direct reduction technology. Table I shows, in terms of percentages, the principal items that contribute to the cost of running an electric arc furnace. It is seen that in addition to the fixed costs (labor, depreciation, taxes etc.) electrode costs and power consumption are the dominant inputs, and it follows that process changes that would ultimately reduce any of these cost components would have a significant impact on the efficiency of the operation. There are three main areas where progress in arc furnace design and operation must be directed in the next decade (Committee on Technology, 1981). 1. Increased furnace productivity 2. Reduction in processing cost 3. Improvement in the thermal efficiency of the furnace An estimate of the current operating efficiency of the electric arc furnaces may be obtained by comparing the theoretical minimum energy consumption per ton of steel with those achieved in operational practice. Theoretically 330-360 kw-hrs of electricity are required to melt one ton of cold scrap. For superheating, 8-12 kWh per 100°F are required. The actual energy requirements are given in Table II. It is seen that furnaces currently operate at 70-80% efficiency, with the major heat loss from the furnace resulting from the waste gases (Committee on Technology, 1981). While it is apparent that operational experience has produced a technology that is reasonably energy efficient this has been achieved in the almost complete absence of any detailed knowledge concerning the fundamental heat transfer mechanisms occuring in the furnace. The purpose of the present paper is to present a case for the usefulness of mathematical models in increasing the thermal efficiency of furnaces by investigating these heat transfer mechanisms and then combining this knowledge with existing electrode regulator mechanisms to produce truly efficient power cycles for melting and refining. In particular, existing mathematical models describing convection, radiation, and electro-magnetism in the furnace should be employed, and the development of optimization models which balance the cost of electrodes and energy against the thermal efficience of the furnace should be undertaken. Recent work in this laboratory (Szekely, McKelliget, 1981, 1982, 1983; Szekely, McKelliget, Choudhary, 1983) has made a useful start towards solving the problem of heat transfer within the electric arc furnace but the work still needs to be directly related to existing furnace power cycles and tested against plant scale measurements.

Jan 1, 1984

By E. S. Bumps

A series of macrographs are presented for the purpose of graphically recording the strain phenomenon that accompanies the energy transition in the Charpy impact testing of a mild steel that is susceptible to strain aging. STRAIN patterns in mild steel Charpy impact specimens were obtained in order to determine whether, on the first appearance of plastic strain during deformation, the initial fracture cracks appear in the region of plastic strain or in the elasti-cally deformed regions between. Although this attempt to locate the initiation of cleavage was not successful, the observed strain patterns illustrating various stress conditions in partially deformed Charpy specimens are presented along with a discussion of the possible dependence of transition energy on the yield phenomenon. Earlier work on the development of strain patterns in mild steel have been reported by Fry1 and later by Jevon.2 Harris, Rinebolt, and Raring3 observed characteristic strain markings on the surface of Charpy V-notch impact specimens fractured above and below the transition temperature which they presented schematically. It is intended that the strain figures presented here will add to the literature a graphic correlation of strain with transition energy in impact specimens. Samples of % in. round hot rolled, 0.20 pct C steel were machined to standard 0.394 in. sq, V-notch Charpy impact specimens. Preliminary testing involved determination of transition temperature, Fig. 1, using a Sontagg impact tester. These data were subsequently used to select temperatures above, within, and below the transition range at which specimens were partially deformed. Partial deformation was obtained by either varying the energy or the testing temperature, see Table I. Macroscopic strain figures shown in Figs. 2 to 19 were produced by several metallographic repolish-ing and etching steps. The macroetchant used was as follows:4 120 g HCl, concentrated; 100 ml water; and 90 g cupric chloride. Strain figures were obtained on the outer surface and on sections through the central portion of the impact specimens in order to determine an approximation of the volumetric strain pattern. In the tensile strain figures reported by Jevon, it was found that strain etching would not work immediately following strain unless the material was heated to 200°C. The impact strain patterns presented here were obtained without this heating, but the specimens were not etched until ten months after straining. This confirms a discussion of Jevon's paper, in which it was pointed out that strain figures can also be developed after aging for long periods of time at room temperature. Hardness of the strained and unstrained portions, revealed by the etched pattern, was explored using R, impressions converted to R, hardness values. Discussion of Results In the impact test, as in the tensile test, some parts of the specimen yield and deform plastically, while other regions are deformed only elastically. The plastic deformation bears a relation to the imposed stress pattern. In the strain figures presented here, the plastically deformed regions are the dark etching ones. The strain figures are always symmetrical because the stress state in the Charpy-type specimen under impact loading is symmetrical. The difficulties encountered to produce initial cracks are intimated in Figs. 2 and 4. At a temperature of —75ºF, the stress was not sufficient to pro-

Jan 1, 1953

By W. A. Tiller, D. H. Lane

A simple zone melting technique for investigating the effect of ultrasonic irradiation upon ingot solidification is described. The effect of i) ultrasonic power level, ii) freezing velocity, iii) constant or variable frequency, iv) direction of irradiation, and v) transducer-cozlpling bar joint upon the grain size of type 316 stainless steel have been investigated. The results of this study support the postulate that the ultrasonic vibrations increase the nucleation probability in the layer of liquid adjacent to the freezing interface. In the first paper of this series,l the possible mechanisms whereby ingot structure may be altered by irradiating a solidifying melt with ultrasonic vibrations have been discussed. A new technique for efficiently introducing the ultrasonic energy into the solid-liquid interface region was presented and applied to ingot preparation by the consumable-electrode arc-melting technique. The experimental results support the postulate that the ultrasonic vibrations may refine the ingot structure by increasing the nucleation probability in the zone of liquid adjacent to the solid-liquid interface. The present paper describes the application of the same technique to a relatively simple laboratory-scale zone-melting apparatus. This apparatus is found to be well suited to the detailed study of ultrasonic technology in this area and allows one to determine, in particular, the minimum ultrasonic power level needed to produce a certain grain size in a particular material. The results of this study support the nucleation mechanism for grain refinement, but do not provide any deeper insight into the specific nucleation mechanism responsible for the effect. EXPERIMENT The apparatus used in these experiments is shown in Fig. 1 and illustrated schematically in Fig. 2. The material to be studied, type 316 stainless steel, was in the form of a 3/4-in. sq bar 30 in. long. This bar was placed in a square open-topped mold with open ends made from high-purity graphite coated with a flame-sprayed Al2O3, skin. Surrounding the crucible was a molybdenum susceptor with 3/8-in. diam holes spaced at 1-in. intervals along its length to serve as sight ports. A tapered transducer horn was brazed to one end of the specimen. The entire assemblage was enclosed in a quartz tube, the transducer itself projecting out one end and resting in a cooling tank. A vacuum seal between the coupling bar and the end plate enclosed one end. A similar plate and seal enclosed the other end. The system is gas tight and can be operated under vacuum or an inert atmosphere. For these experiments, flowing argon at 15 in. of Hg pressure was used. The heat source for melting the stainless steel specimen was a 2-in. long 3-kc induction coil placed around the quartz tube; this source heated the susceptor, inductively melting about a 3-in. zone of the sample by radiation. To move the molten zone at a specified rate, the induction coil was moved down the tube at this rate with the aid of a simple pulling device. Thus, the sample could be irradiated at varying ultrasonic frequencies and power levels and could be solidified at varying rates. The power input to the transducer was measured using a "John Fluke Model 120 VAW-Meter." 1 The power delivered to the interface region is probably only about 50 pct of that measured on the VAW-meter. In a typical run, when the ultrasonic power was turned on, the interface of the molten zone closest

Jan 1, 1961

By Edward B. Walker, Michel Grosmangin

The geological and economic conditions peculiar to the Greater Oficina area are presented to demonstrate the necessity of a low-cost, well-site method of distinguishing gas-bearing formations. The method of gas detection with the neutron log is briefly discussed and its limitations are explained. A new method is described which consists in running a second neutron log with a larger source-to-detector spacing. Field data indicate that under favorable conditions the larger spacing response is proportionately more influenced by the virgin gas zone than is the shorter spacing response. One important condition is that the gas sands be invaded, with a diameter of invasion equal to about two to three times the hole diameter. The calibration of the longer spacing log is made so that the two logs read the same deflection in shale and in a known water or oil sand. Under such conditions, gas is indicated by a positive separation, i.e., the curve for the longer device is displaced to the right of the curve for the shorter device. Because of the non-linearity of the long spacing response, low porosity formations also show positive separations. In sands with large porosity variations, the gas sands can no longer he located visually. They can be detected on a plot of shorter spacing vs longer spac-ing deflections. INTRODUCTION In the Greater Oficina area of Eastern Venezuela, the rapid and accurate detection of gas from well logs is of primary importance because of a combination of economic, geologic, and operational conditions. Briefly, these conditions are: economic—there is no market for gas at the present time; geologic—a single well may contain as many as 30 or more oil or gas sands for which intervals -to be tested must be selected; opera-tional—first, once opened to the casing through perforations, gas sands are extremely difficult and expensive to squeeze off, and second, gas detection must be rapid because the geologist must decide immediately, at the well, which sand to perforate. During the early period of exploitation in Greater Ofi-cina, when clay base muds were used, sidewall samples, together with electric logs, gave fairly good distinction between oil and gas sands. When exploitation became concentrated on deep fields of poorer sidewall sample recovery, and after the advent of oil emulsion muds, now the standard drilling fluid in Greater Oficina, the regular neutron log became the most reliable indicator of gas. In 1953, R. Norelius devised the dual-spacing neutron technique for gas detection. The dual-spacing neutron log has proved to be highly successful in detecting gas and has been adopted as a regular survey by all of the oil companies of the area. Several hundred dual-spacing neutron logs have been run in Eastern Venezuela and several tests per well are available for positive evaluation of the logs. The findings outlined below are based upon this extensive field experience. GEOLOGICAL CONDITIONS OF THE GREATER OFICINA AREA The Greater Oficina area lies on the south flank of the Eastern Venezuela Basin (Fig. 1). Nearly all accumulations of oil and gas in the area are trapped, in whole or in part, against normal faults. All known oil and gas reservoirs in Greater Oficina occur in the Ofi-cina formation (Miocene-Oligocene) or in the "U" sands. The U sands are the lithologic equivalent of the Merecure group (Otigocene-Eocene), which contains oil in many fields north of Greater Oficina. Most of the petroleum produced in Eastern Venezuela is from the Oficina formation.

Jan 1, 1958

By Carlos E. Roggero

The influence of high temperatures on the zinc roasting practice has been investigated by full-scale tests in fluid bed reactors operating at temperatures from 950° to 1150°C. It was definitely shown that, throughout the range, an increase in tem perature resulted in a 2 to 3 pct increase in zinc solubility because of decreased content of zinc fer-rite and lowered sulfide sulfur. The former is attributed to thermal decomposition of ZnFe,O,, and the latter to increased oxidation rates, ad longer retention times. Data on the gveatly increased volatilization of lead, cadmium, and silver above 1000°C, are presented. A considerable fraction of the iron present in the feed was also transferred at high temperatures from the coarse roaster discharge to the flue dusts. AS part of its metallurgical complex1-3 situated in a 12,000 it Andean valley at La Oroya, Peru, Cerro de Pasco Corp. (a wholly owned subsidiary of Cerro carp.) operates a 150 short ton per day electrolytic zinc refinery. Electrolysis is carried out at a cathode current density of 65 amp per sq ft with an electrolyte content of 55 g per liter of Zn and 150 g per liter of su lf uric acid. Due to the high iron content of the marmatitic concentrate used, a large fraction—about 15 pct—of the zinc reports in the leach residues. To minimize such losses, efforts have been exerted toward improving calcine solubility. One method, as noted in the literatre,, is to retard zinc ferrite formation by decreasing the roasting temperature. Unfortunately, such a procedure tends either to reduce the roaster throughput or increase the sulfide sulfur in the calcine. Consequently, this approach was discarded in favor of experimental work in the opposite direction, i.e., high temperature roasting. Full- scale tests were promising and resulted in the granting of a patent to Cerro de Pasco carp.' After a brief account of plant equipment and operating procedure, this paper describes the tests made and attempts to assess the results obtained. GENERAL PLANT LAYOUT AND OPERATION The Roasting Plant, see Fig. 1, comprises an agglomerating plant feeding three fluid bed roasters with a combined capacity of 10,000 tons per month. The Peruvian patent rights on this process were purchased from the New Jersey Zinc Co. The concentrate, assaying: is pelletized to a -3 +14 mesh product and fed to the fluid bed roasters. The roaster exhaust gases pass through a waste heat boiler, cyclones, a fan, and an electrostatic precipitator. Approximately half of the dust collected in the cyclones returns to the pellet-izing plant as one of the binding ingredients, the remainder joins the cooled bed discharge ('overflow') and is conveyed to the grinding plant. The -35 mesh product obtained, together with the dust collected in the electrostatic precipitator constitute the feed to the leaching plant. Batch leaches are made in vessels with mechanical and air agitation, the residues are separated and washed in Burt Filters, and pumped to storage ponds. THE FLUID BED ROASTERS Two reactors are as shown in Fig. 2, and the third,' of about the same configuration, is approximately 40 pct smaller. The total grate and freeboard (just below the gas outlet) areas measure 170 and 426 sq ft respectively. The feed, continuously weighed and controlled by Merrick Weighto-meters fitted with variable speed motors, enters the reactors at the top of the expanded bed level. The coarse calcine overflows through the opposite end by

Jan 1, 1963

By R. Stefanko

The use of strain gauges and compression pads for an underground bolt installation in a central Pennsylvania coal mine revealed that satisfactory anchorage could not be maintained in the shale stratum that constituted the immediate roof. Comprehensive laboratory tests resulted in a new shell designed with an increased area of contact and smaller surface serrations. Retightening of the bolt was also found to be beneficial for maintenance of high load values. Roof bolting in coal mines has progressed very rapidly in the last decade, and today this method of support is in general use. There are many theories concerning the functions of roof bolts, but the importance of beam building is indisputable. Proper tension in the bolts minimizes shearing along bedding planes and creates a thick, competent beam from individually weak layers. Bolting must be accomplished immediately upon exposure of the roof, and bolt tension must be maintained if roof failure is to be prevented. Seams are being mined today with roof bolt support where conventional timbering was not effective.' The widespread use of continuous mining equipment was made possible by roof bolts which permit long supported spans free of obstructions. Since adequate anchorage is the key to successful bolting, better methods for determining the efficiency of anchorage are continually being sought. Attempts have been made to measure bolt loads, thus assessing anchorage efficiency by employing sensing devices between the bolt head and roof. 3-s None of the techniques appears to be very accurate, and all have at least one serious deficiency. The greatest efforts are being directed toward the standardization of the pull test.6" Nevertheless, the author believes that the pull test is only one criterion for establishing the efficiency of anchorage and not necessarily the most important one. The conventional pull test involves the short-term application of forces, whereas the success of roof bolt installations is dependent upon the ability of anchorage to sustain relatively long-term forces. Therefore, it would appear that the time-dependent function of the anchor is the single most important parameter for the success of roof bolting in many types of rocks. UNDERGROUND TESTS Strain gauges and compression pads were employed to measure bolt loads in a central Pennsylvania coal mine.8 Bolting had been employed only sporadically in the shale top since dubious benefits were obtained with this type of support. Table I shows some typical results from this investigation. Anchorage losses were extremely variable among the bolts, but all showed a considerable degree of bleed-off. The tests indicated that anchorage efficiency was extremely low in this type of shale. The results confirmed that bolting under these conditions was practically worthless, and thus a waste of material and labor. Probably even more important, bolting constituted a hazard when reliance was placed upon it for support. Certainly the complete lack of confidence in roof bolting, which was apparent in the mine personnel, was justifiable since the bolts did not accomplish their purpose. PRELIMINARY LABORATORY BOLT TESTS The extreme losses in bolt tension that were detected in underground installations prompted a comprehensive study to assess the causes. However, preliminary studies were first made to determine the combined stresses in a roof bolt and to prove conclusively that the observed bleed-off phenomena were due to anchorage: slippage and not to some other physical manifestation. In all of the ensuing tests

Jan 1, 1962

By T. J. Carew

INTRODUCTION The application of micro-computers to the evaluation of an advanced exploration project is illustrated by reference to a large project in the Sudbury Basin region of Canada. The deposit in question is polymetalic (Cu, Pb, Zn, Au, Ag) with a strike length of 3048m (10000ft) and has been explored to a depth of 457m (1500ft) by approximately 1350 diamond drillhole of between 9 - 305m (30-1000ft) in length. The large amount of data involved and the ability to rapidly recalculate geological reserves in response to fluctuating metal prices were key factors in the application of a micro-computer based evaluation system. The evaluation software was implemented at two levels, with data capture implemented mainly on - an entry level workstation comprising an IBM-PC compatible (PC-XT) micro-computer equipped with a 20Mb hard disc, printer and RS-232 serial communication facilities. Data analysis, display, geo- logical modelling and processing was carried out on a high-level workstation based on a Hewlett-Packard 9000 super- micro computer and peripherals, including a 40Mb hard disc, tablet digitizer and plotter. Basic drillhole data was entered either directly at the super- micro or transferred from the PC via the RS-232 link. The evaluation process proceeds once the data is edited and in a "clean" format within a master project database. The software is comprised of a suite of modular, integrated programs based on ease of use, interactive graphics and optimized for the computer workstation. Drillhole data was displayed and plotted as hard copy plots on which geological interpretations were developed. The data was copied into small manageable projects consisting of 100 to 150 drillholes, within which a sectional model was created such that all the models are interconnected along the entire strike with no overlaps. Geological reserves were derived by developing a set of function variables, including Net Smelter Return, within the database. The values of these functions can be displayed on the model sections and "ore” zones defined in accordance with pre-determined cutoff values. Interpolation of the modelled data was then carried out and geological reserves calculated and reported. DATA CAPTURE Drillhole data for the project consisted mainly of existing drillhole logs, although the system allows for the entry of new information as it becomes available. The structure and format (i.e. number and length of variable fields) is user defined. The log for this project comprises an abbreviated section for name, competency, grain size, texture, colour and alteration. Fields are defined for structural information regarding bedding and fault angles and up to seven mineral identification columns and percentages are available. Assay information consisting of the sample number, width and six determinations (Cu%, Pb%, Zn%, Fe%, Au opt., Ag opt.) along with a comments section of 25 characters completes the log. One powerful feature of the data- base is the ability to set up function variables that are mathematical and/or logical combinations of the project variables, enabling the user to develop economic variables such as Net Smelter Return. These functions include current treatment costs, deductions and penalties and can be rapidly recalculated within the database to accommodate changes in metal prices, forecast recoveries and exchange rates (Table 1).

Jan 1, 1987

By James A. McGurty, Walter J. Koshuba, Samuel G. Gordon, Gilbert E. Klein

ONE of the problems encountered in working with metals at elevated temperatures is the instability resulting from solid-solid diffusion at a -common interface. A determination of the nature and magnitude of this phenomenon is important as related to structural properties of materials potentially useful in high temperature applications. This paper is concerned with the solid state reaction between metallic molybdenum and beryllium at elevated temperatures. In the older literature,' there were no known inter-metallic compounds in the system Be-Mo, and the list of beryllium intermetallics was rather small. New compilations have been made by Smithells' and by Taylor," listing all the then known beryllium binary intermetallic compounds. In addition to these, some new phases have just been reported' in the system Zr-Be and some further compounds of the type MBe,3 have been currently described. The new compound MoBe,, which is reported upon in this paper differs considerably from the above mentioned MBe13 group, and will be discussed in detail. Diffusion Study The nature of the solid diffusion at a Mo-Be interface was determined by sealing a beryllium rod inside a molybdenum capsule and heating at a temperature of 2000°F' (1100°C) for 100 hr. The molybdenum capsule was fabricated from % in. swaged molybdenum rod obtained from the Fansteel Metallurgical Corp. The beryllium metal was obtained from Brush Beryllium Corp. as % in. cold-drawn rod. This material assayed 99.05 pct Be and contained as impurities 0.84 pct Be0 and 0.19 pct Be2C. The molybdenum capsule was % in. in OD x 2 in. long. To prepare it, a concentric hole 0.250 in. + 0.001 in. — 0.000 in. in diam was drilled and reamed in one end of a rod to a depth of 1 '/2 in. A 1 in. long beryllium rod 0.250 in. + 0.000 in. — 0.001 in. in diam was pressed into the molybdenum capsule. A molybdenum plug 0.250 in. & 0.001 in. in diam x 9/16 in. long was then used to seal the beryllium in place. The capsules were placed in a molybdenum resistance furnace and heated at 2000°F (1100°C) for 100 hr. On cooling, the specimens were cut and examined metallographically. Fig. 1 is a micrograph at X250 of a portion of the interface from a transverse section. Four phases are clearly visible, with sharp boundaries between them. Phase A is a section of the molybdenum capsule; phase B is the molybdenum-rich intermetallic composition MoBe,; phase C is the beryllium-rich compound MoBe13; phase D is a section of the beryllium rod. All phases were readily polished to a high metallic luster. The molybdenum-rich phase has a pronounced purple tinge. The beryllium-rich phase (C) is only slightly darker than the pure beryllium. In polarized reflected light, however, it shows striking birefringence between crossed Nicols. The black areas represent flaws or pores in the material. A small representative amount of powdered material from each of the phases was carefully removed under the microscope with a diamond tool. With this material, powder X-ray diffraction patterns were made for the identification of each phase. Table I lists the X-ray diffraction spacings and corresponding indexes characteristic of these intermetallic compounds. Synthesis To establish the formula of the new intermetallic compound, X-ray diffraction patterns were made from powders obtained from solidified melts of known composition. The syntheses were made by

Jan 1, 1952

By William P. Roe, James F. Ellis, W. P. Fishel

This paper reports the distribution of sulphur between iron and titanium in Fe-Ti-S alloys and in Fe-Ti-C-S alloys. The compound TiS was found, which exists as a separate phase at temperatures below 1200°C. Titanium in steels reacts with sulphur in preference to carbon. THE general relationship between sulphides and oxides suggests that titanium should form a sulphide having properties similar to those of titanium oxide. Specifically, titanium should form a sulphide having a high melting point, indicating a stable compound of low solubility in iron. In order for titanium to function as a desulphurizer or sulphur-fixing agent, it must form a stable sulphide. In order for titanium to be useful in steels as a sulphur-fixing agent, it must react with sulphur in preference to carbon; and to prevent red shortness, the sulphide formed must have solubility characteristics such that grain-boundary precipitation of a low melting phase be prevented. The terms desulphurizer and sulphur-fixing agent when used in this paper mean that titanium effectively ties up the sulphur as a stable sulphide of titanium and prevents the formation of FeS. The partition of sulphur between iron and titanium was studied first in a series of Fe-Ti-S alloys with carbon absent, and then in similar alloys with carbon present. It has been established1 a that titanium forms in Fe-Ti-S alloys a sulphide of undetermined composition which can be identified microscopically, and that the titanium-sulphur compound does not respond to sulphur printing. It has been suggested" that titanium acts as a sulphur-fixing agent, although little proof has been given. A report% f The Advisory Committee on Metals and Minerals summarizes the existing knowledge concerning substitutes for manganese in steels. Distribution of Sulphur Between lron and Titanium with Carbon Absent The alloys for this investigation were made by -melting Armco iron, metallic titanium, and iron sulphide in alundum crucibles in an induction furnace. The titanium was added after the other ingredients had melted. In these alloys it is recognized that some TiO, is present, since the melts were made in the air and since no other deoxidizing agent was used; therefore, some of the titanium was not available for union with sulphur. Thirteen ingots were made. Ingots 2 to 8 were cast in baked-sand molds; ingots 12 and 13 were cast in metal molds; and ingot 9 was allowed to cool in the crucible in which it was melted. All ingots were annealed at 900°C for 3 hr and were cooled slowly in the furnace. Subsequent information indicates that this anneal had no effect upon the titanium sulphide particle size, since the sulphide does not go into solution at this temperature. The ingots as-cast were approximately 8 in. long and % in. diam. The compositions of the eight ingots and the results of the partition of sulphur are recorded in Table I. Total titanium and total sulphur were determined by standard gravimetric methods. Sulphur, as iron sulphide, was determined by the evolution method. Boiling HC1 (1:4) liberates the sulphur from iron sulphide, but leaves the titanium sulphide practically undecomposed. A complete separation of titanium sulphide and iron sulphide cannot be made by digesting these compounds in dilute HC1 since titanium sulphide was found to dissolve slowly. The amount of titanium sulphide decomposed will depend upon the time in contact with the acid and upon the particle size of the sulphide. The point

Jan 1, 1952

By W. M. McCardell, W. O. Winsauer

The abnormal conductivity found in shaly reservoir rocks containing an electrolyte is shown to be a consequence of the electrical double layer in the solution adjacent to charged clay surfaces. This increased conductivity results from a higher concentration of ions in the double layer than in the solution in equilibrium with the double layer. It is shown that the magnitude of the increased conductivity of a shaly reservoir material is influenced by the concentration and type of ions in the equilibrium solution as well as by the colloidal nature of the rock. INTRODUCTION An important factor in the quantitative interpretation of the electric log is the resistivity factor of reservoir rock. The resistivity factor is defined as the resistivity of the rock when completely saturated with an electrolyte divided by the resistivity of the electrolyte itself.' In the normal case, the resistivity factor for a particular rock sample is independent of the resistivity of the electrolyte and reflects the pore geometry of the rock.' In 1949. Patnode and Wyllie' showed that in some cases the resistivity factor is not constant, but instead varies with the resistivity of the electrolytic solution. It was shown that clean sands behave normally—i.e., that the resistivity factor does not vary with resistivity of the electrolyte — but that sands con- taining shale and clay may exhibit abnormally low resistivity factors when the solution used to saturate them is of fairly high resistivity. At low resistivities of the electrolyte, the resistivity factor for a shaly sand appeared to approach a normal behavior. It is evident that the resistivity factor of a shaly sand is dependent upon factors other than pore geometry when the solution used to saturate it is of high resistivity. Patnode and Wyllie, and later de Witte,' assumed that the conductivity of a shaly sand saturated with an electrolyte could be represented as the sum of two quantities. One of these was assumed, in effect, to be the conductivity which would be expected if the sample were a clean sand. and the other was assumed to be a conductivity inherent in the sample itself. The latter was supposed to be constant for a given rock sample regardless of the solution used to saturate it. The source of this added conductivity was ascribed to "conductive solids." In actual practice: the effect of the abnormal behavior of shaly sands is of minor importance except when the resistivity of a formation such as a sand is high. Thus the effect is more important when the sand is saturated with a dilute brine than when it contains a more concentrated electrolyte. The effect is also more important when the sample contains oil or gas than when it contains only saline water. Recently it has been suggested that the porosity of a stratum may be estimated from the electric log by use of the resistivity of the invaded zone." This is the zone flushed with the filtrate from mud used in drilling the well. which is ordinarily very dilute brine. When the method is applied to shaly sands, the effect of abnormal conductivity becomes of importance. This report describes an investigation of the mechanism responsible for the abnormal behavior of the resistivity of shaly rock saturated with conducting solutions. The investigation

Jan 1, 1953

By Caudle B. H., Cooper H. E. Jr., O. K. Kimbler

The results of studies of areal sweepout behavior in nine-spot injection patterns are presented in this paper. The ratio of the production rates of the two types of producing wells in a nine-spot pattern is considered in its effect on breakthrough. A model study was used to develop a method to predict the production histories of both side and corner wells and to develop the production history of the pattern or the field. INTRODUCTION The importance of areal sweepout behavior in injection operations has been recognized for a number of years. We now know that the fraction of a reservoir which will be reached by an injected fluid is a function of the geometric arrangement of the production and injection wells and of the mobility ratio of the fluids. Of these two, the mobility ratio (which is a measure of the relative ease with which the oil and the injected fluid can move through the reservoir) appears to have the greatest effect on recovery. The effect of mobility ratio on production history has been reported for most of the dispersed injection patterns (i. e., five-spot, staggered and straight-line drives).4-6 ere has been very little published on the nine-spot injection pattern. This may be because the two types of producing wells in the nine-spot pattern can—and sometimes should —be produced at different rates. This adds a second variable (the fist being mobility ratio) to be covered in a study of the nine-spot flooding network. Muskat1 has reported the sweep pattern efficiency at breakthrough for a mobility ratio of one at various ratios of producing rates for the two types of wells. For these conditions he found maximum oil production at breakthrough to occur when the corner well (the producing well farthest from the injection well) is produced 10.7 times as fast as the side well. Other investigatorsa2,3 have studied a few of the many possible operating conditions possible with this injection pattern. This paper presents the results of studies which are strictly applicable to a nine-spot injection pattern surrounded by other nine-spots in a homogeneous reservoir and which has no flowable gas present (no oil bank is formed). Although the full ranges of the variables mentioned above have not been covered, the results reported here should allow reasonable estimates of field operations to be made. EXPERIMENTAL The well spacing geometry of the nine-spot pattern is shown in Fig. 1. Here we see that each injection well is surrounded by eight production wells arranged in a square. Four of these producing wells are located at the corners of the square; the other four are in the midpoints of the four sides. These two types of producing wells are called "comer wells" and "side wells" respectively. It is the ratio of the producing rates of these two types of wells that affects the breakthrough recovery, as calculated by Muskat.' This ratio is defined as the total producing rate of a corner well divided by the total producing rate of a side well. The model used in this study represented one-eighth of a nine-spot pattern, as shown in Fig. 1. It contained the equivalent of one-fourth of a side well, one-eighth of a comer well, and one-eighth of an injection well. Because of these proportions, the actual producing rate ratios in the model were one-half of the ratios of producing rates as

Jan 1, 1965

By H. I. Aaronson, C. Laird

Cold rolling by 50 pct a A1-4 pct Cu alloy containing many 0' plates has been found to accelerate markedly the transformation of 8' to 0 upon further aging. Although the basic mechanism of this transformation remains unchanged by plastic deformation, the nuclea-tion kinetics of 8 become appreciably more rapid and also less dependent upon temperature. Particularly at lower aging temperatures, rounded idiomorphs replace several faceted rnorphologfes. The rates of growth of 9 idiomorphs in deformed specimens aged at 300°C are appreciably more rapid than simple volume diffusion control allows. This observation is shown to be explained by an excess vacancy, rather than by a dislocation Piping mechanism of growth. ThE rather complex phenomenology of the 8' —8 transformation in Al-Cu alloys has been recently elucidated in considerable detail by means of transmission electron microscopy.'-4 This technique was also employed in the present investigation in order to examine the effects of plastic deformation upon the transformation of 8' to 8. The mechanism of the transformation in undeformed Al-Cu alloys has been established as the following sequence of events.1"4 The first step is the nucleation of 9 at (Y:8' boundaries. Nucleation of a 0 crystal takes place, however, at only a very small proportion of the 8' plates present. Each 0 crystal simultaneously consumes the host 8' plate and the a! in the immediate vicinity, with growth into a being the rate-controlling process. The remaining 8' plates are then dissolved as they fall under the concentration shadow of the growing 8 crystals. The evidence on the effects of plastic deformation upon these processes is intriguing, but much less detailed. The careful X-ray studies of Graf and Guinier have shown that the aging times required to form detectable amounts of 8' and 8 are reduced by prior cold working. Thomas and Nutting confirmed these results by replication electron microscopy. Nile-shwar,* on the other hand, reported that creep deformation decreases the rate of formation of 0. While this difference may have been caused by the use of concurrent rather than successive deformation and ag- ing, the X-ray technique which he used was able to monitor only the 0 phase. It is thus possible that the times needed to form 8' were increased moreg than the kinetics of 8' — 8 transformation were accelerated. At 90 pct deformation by cold rolling, Graf and Guinier found that the usual 0' —0 8 sequence is reversed: 0 forms first. von Heimendahl 10 confirmed this result with transmission electron microscopy. Pollard and Nutting, 11 and more recently Driver and Barrand, 9 having used the same technique, report that 9 also forms first during creep deformation. In the present study, the maximum amount of deformation was limited to 50 pct reduction by cold rolling in order to insure that 8 formed principally by the decomposition of . I) EXPERIMENTAL PROCEDURES This investigation was conducted on an Al- 3.93 pct Cu alloy, prepared as previously described. 4 Morphological and crystallographic effects of plastic deformation were studied in specimens annealed 6 hr at 548°C, quenched, and then aged for either 3 or 8 hr at 250°C to form large numbers of 0' plates. After cold rolling to a 50 pct reduction in thickness, the

Jan 1, 1969