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By E. T. Turkdogan, P. Grieveson

Experimental results are given for the rate of oxidation of ferrous iron to ferric iron in pure molten iron oxide by carbon dioxide + carbon moloxide mixtures at 1550°C. It is shown that the rate-controlling process is the interdiffusion of iron and oxygen atoms within the melt. The inter-diffusivity of iron and oxygen in the melt is obtained from the results and the value of (5.0 * 1.0) x 10-5sq cm per sec is recommended for the temperature of 1550°C. Similarly, it is also found that the rate of reduction of molten iron oxide is con -trolled by diffusion in the melt; however, apparent interdiffusivity values from these experiments are 10 to 20 pct higher than those obtained in the oxidation experiments, by virtue of convection arising from density difference. The results of the oxidation experintents are used to calculate an estimated self-diffusivity of iron in molten iron oxide of (1.5 * 0.5) x sq cm per sec. BECAUSE of the industrial importance of iron oxides, the study of the kinetics of both the reduction and oxidation of the solid oxides has received a great deal of attention. However, knowledge of the kinetics of similar reactions in the liquid state is very meager. Dancy 1 studied the kinetics of reduction of molten iron oxide by carbon in pig iron and found that the reaction is very fast. It was concluded from the results that the reduction of molten ferrous oxide is a first-order reaction up to 80 pct reduction, while

Jan 1, 1964

By B. G. Klugh

The present paper represents a preliminary investigation of the ultimate structure of iron-bearing materials which have been subjected to heat treatment for the purpose of agglomerating the fines, or for chemical changes, or for both. Primarily, the object of this inquiry was to determine the relation of the microstructure of each of these materials to its specific susceptibility to the action in the blast-furnace. It is hoped that this small contribution will serve as a nucleus to a line of research that will throw some light upon the debated questions involved in blast-roasting. Thus far the investigation has been conducted along lines of analogy of known principles, rather than through the application of any well-defined system of microscopic petrography. This is obviously due to the fact that we are dealing with ma-terials which are the artificial products of a new art, rather than with the natural materials from which the essence of the pure science has been evolved. In the limited time allowed for this research, it has been conducted upon those materials the chemical content of which allows of their use commercially in the blast-furnace. The following microphotographs are arranged in the order of the degree of complete fusion to which the mass in question has been subjected, in effectively binding the particles together. A very notable fact here clearly demonstrated is that the degree of fusion to which the material has been subjected is inversely proportional to the reducibility of the product. The characteristic of the material under consideration to which reducibility is almost universally attributed call be progressively traced in the following arrangement, through the identity of the obvious microscopic constituent. Furthermore, the degree of fusion to which a bod? has been subjected is recorded in the presence of resultant products of fusion in that body. Such readjustment is generally apparent

Jan 1, 1914

By Arthur Taggart

SOME years ago, A. M. Gaudin and one of the authors published a paper showing removal of tar acids from solution by sulfides preferentially as compared to gangues (specifically by galena as compared to quartz).1 The underlying phenomenon was classed as adsorption, and the paper went on to develop the general thesis that so far as water-soluble frothing and collecting agents in flotation are concerned, the phenomenon of adsorption is one of controlling importance. Adsorption was defined in that paper as "a process of rearrangement of a system, which results in establishing a difference in concentration, as between the interfacial layers and the bulk of the phases, of a substance or substances initially uniformly dispersed in one or several of the phases." The paper went on to develop the relation between adsorption and surface energy according to Gibbs' equation (which may be thrown into the form U/c = KdT/dc, where U = excess concentration in surface layer, c = concentration, T = surface tension, and K is a constant), and pointed out that, according to this equation, degree of adsorption and change in surface tension vary directly. The present paper offers a somewhat different definition for the term adsorption; and sets up, in sweeping terms, the generalization that simple chemical reaction underlies the functioning of the flotation reagents which control mineral collection, when these reagents are soluble in and act from solution in the water of the pulp.

Jan 1, 1930

By H. A. Coy, James A. Noble

The Mascot mines of the American Zinc Co. of Tennessee are situated at Mascot, Tenn., 14 miles northeast of Knoxville, on the Southern Railway. The district is centrally located in the Great Valley, or Appalachian Valley Province. Prior to 1900, a small output of zinc was obtained from oxidized ore mined in open pits. In 1900, a shaft was sunk to sulfide ore, and in 1903, a second shaft was put down, neither being as deep as 200 ft. The American Zinc Co. of Tennessee began drilling in 1911, and outlined an ore-body to which its No. 1 shaft was sunk, to a depth of 365 ft. Since that time, the American Zinc Co. of Tennessee has been the only operator in the district. The Federal mining laws have never been in operation in Tennessee and mining lands are as irregular in boundary and area as farm lands. Ownerships are generally held in fee. In most cases the surface and mineral rights are transferred together. Electric power is supplied at 66,000 volts by the Tennessee Power Co., from a hydro-electric plant at Parksville, Polk County, Tenn., 100 miles from Mascot. No other power is used, but an emergency steam plant is held ready in case of interruption of service. Labor is all native and non-union. Negroes are employed for most of the shoveling, and for a few miscellaneous jobs, but for almost no other work. Exploration Exploration is carried ahead of mining largely by surface drilling. Both churn and diamond drills are used. Holes are not spotted according to geometric plan, but to block out ore outlines with the least number of holes. Churn-drill cuttings from each 5-ft. run are mounted for formation record, and in ore ground, all the bailings from each 3 ft. of advance are sampled and assayed. Diamond-drill cores are sampled and a specimen core filed for formation record. In ore ground, all the core

Jan 1, 1925

By B. H. Sage

AN apparatus is described for the measurement of the pressure-volume-temperature relations of pure substances, simple mixtures and complex mixtures with an over-all absolute uncertainty, which is usually not more than 0.2 per cent. The equipment is suitable for studies in the gaseous, two-phase, and liquid regions. The behavior of such systems may be investigated at pressures as high as 10,000 lb. per sq. in. for temperatures between 70° and 600° F. The methods of measurement and the construction of the apparatus are described in some detail. The measurement of the volumetric behavior of multicomponent systems requires the simultaneous measurement of the pressure, volume, temperature and weight of each component of the system. In the present apparatus a sample having constant weight is investigated at a number of independently controlled pressures and temperatures, there-fore it is necessary only to establish the weight of each component added before a given set of measurements. This method is in distinction to that in which the total volume remains constant and the pressure is varied by addition or removal of material, the system having variable weight. An objective in the design of the apparatus to be described was to develop equipment that would yield results involving no uncertainties larger than 0.25 per cent throughout the range of pressures from 150 to 10,000 lb. per sq. in. at temperatures between 70° and 600° F. Although this over-all absolute uncertainty of measurement may not appear to be small, it necessitated care in the plans for control and measurement of each of the fundamental variables. In general, any uncertainty greater than 0.05 per cent in the pressure, volume, absolute temperature or weight of each component was considered undesirable; therefore the attempt was made to obtain a precision of measurement in each case such that the absolute uncertainty would be only half this amount except in certain regions near the ends of the experimental range of the variable under consideration.

Jan 1, 1939

By CLYDE M. EYE

THE Sub-province of Benguet is in the North Central part of the Island of Luzon. Baguio, the capital, is situated on a piateau 5000 ft. above sea level, and is the main health resort of the Philippines. It is rapidly becoming the favorite resort for the China Coast as well, and has many miles of beautiful, curving drives with nearly every pine-covered knoll surmounted by a summer home. The United States Army has a recreation post here, known as Camp John Hay, with a well-equipped hospital, and there is a Country Club with a good golf course adjacent. The weather during the winter months and until late spring is ideal. The business center consists mainly of Chinese and Japanese stores, several hotels, and a large public market, in which are displayed all of the vegetables of the temperate zone, which are flown near Baguio, and many tropical and other products brought up from below. This district is reached from the Coastal Plain either by the old Benguet road built in 1904 by the United States Government, or by the Naguilian road, built some years later. The former is now a toll road, with a line of stages operating over it to and from Des Mortes in connection with the government-owned rail- road. Auto travel from Manila is also along this road, the trip from Manila to Baguio requiring about seven hours, following up the great valley north of Manila for nearly 150 miles to the lower end of the Benguet road, and thence to Baguio, 25 miles. This is an interesting, scenic trip; the road is especially famous for the zig zags where it climbs out of the canyon of the Bued River to the plateau. In the September number of the National Geographic Magazine, a fine aerial picture of this road, as well as of other interesting points in various parts of the Philippines, appears. Freight for the district is taken in mainly over the Naguilian road connecting with the railroad at Bauang. This route follows the ridges of the mountain slope with broad vistas and views of the coast.

Jan 1, 1930

By J. Mackintosh Bell

The history of the South Lorrain mining camp is given and comparisons are made between the local topography and general geology and that of the Cobalt camp. The character of the silver-bearing veins and their analogy to those of Cobalt are given and the theory regarding the cause of the deep seated oxidation in South Lorrain, particularly at the Keeley Mine, is outlined. The oreshoots are described, also the conditions governing their occurrence and position. The mining and metallurgical practice are briefly considered. IN THE numerous districts subsidiary to Cobalt, and carrying mineral deposits similar in character to that world-famous mining camp, the most interesting recent developments have occurred in South Lorrain. The district, the center of which lies about 16 miles southeast of Cobalt, was the scene of a rush in 1907 but, in spite of the success of the Wettlauffer mine, the locality soon lost its popularity, largely on account of the unsavory early history of the Keeley mine. In recent years, following the successful development of this property by the London operators, who acquired it from the liquidator of the original company, and the later conspicuous progress made on the properties of the Mining Corporation contiguous to the Keeley on the north, the district has again come into prominence and, at present, is doing much toward maintaining the gradually declining production of Cobalt itself. Apart from the Mining Corporation of Canada and the Keeley Silver Mines Limited, the principal concerns now operating in South Lorrain are the Lorrain Consolidated, the Trout Lake Mines (operated by English interests associated with the Mining Corporation) and the Canadian Lorrain Silver Mines (operated by the Huronian Belt Co., of London). A number of minor prospects are also active. The Wettlaufer and Currie, on both of which considerable work was done some years ago, are now closed.

Jan 1, 1924

By F. O. Blackwell

It is roughly estimated that some three hundred companies in the United States engaged in mining and the kindred arts now employ electricity in their operations. As all these plants have been installed within the last few years, it is evident that mining engineers have been quick to appreciate the great advantages of the use of electricity and adopt it for their many requirements. In

Jan 1, 1894

By John Griffen

THE modern anthracite breaker or washery uses almost completely a wet method of preparation, which requires, roughly, 1 gal. of water per minute per ton of production per day. The entire anthracite industry uses about 320,000 gal. per min. of water for this purpose or 800,000 tons of water per day. As this water leaves the breakers, it contains fine solids-coal, slate, pyrite, and clay-and is then called silt or slush; as slush is the term most commonly used, it will be employed throughout this paper. The solid content of the slush will be referred to as solids. In the earlier days of anthracite mining, little coal was washed, less crushing was employed, and virgin coal was mined exclusively. As a result, the slush problem was not acute because of the relatively small quantity and the coarseness of the solids. Such slush as was produced could usually be easily impounded and retained or could be discharged into streams without any appreciable pollution being apparent. The character of the fine waste from the breakers, changed materially as its quantity increased until now about 40,000 tons of slush solids are produced daily. Second mining and robbing operations materially increased the quantity of fine solids delivered to the breaker in the mine car. The demand for chestnut, stove and egg sizes, to the exclusion of grate, steamboat, and lump sizes, require finer crushing of the mine-run coal with a consequent increase of fine solids in slush. The use of rice and barley sizes removed a considerable tonnage of coarser solids from the slush but left great quantities of fine solids difficult to retain completely and store and long considered of no possible fuel value. Despite the efforts of the coal operators, the slush solids have found their way into the streams causing, in some cases, serious pollution. The Water Supply Commission of Pennsylvania published, in 1916, a report on Culm in the Streams of the Anthracite Region,1 from which the following is taken: About 40,000,000,000 gal. of water carrying 10,000,000 tons of fine culm are discharged into the water-courses direct, flushed into the mines, or disposed of by various means on the surface. The extent to which the very small sizes of anthracite

Jan 9, 1921

By Jennings S. Cox

The following notes, prepared in 1908, as the result of a personal examination and extensive explorations under my direction in 1906, have been revised and greatly augmented after two subsequent visits and further explorations in 1910. The hard iron-ores of the south coast of Oriente Province, in the island of Cuba, have been known for many years, in fact one mine has been in operation for more than 20 years; but it is only within the past four years that the large mantle-deposits of brown ores of the north coast have attracted serious attention. A. C, Spencer' has described these ores in a paper, entitled Three Deposits of Iron Ore in Cuba, which refers to the Mayari, Moa, and Cubitas deposits. C. M. Weld,2 in a scholarly paper, The Residual Brown Iron-Ores of Cuba, has discussed the character and possible genesis of these deposits with particular reference to the Moa field, calling attention also to the Taco and Navas fields in addition to those described by Spencer. Descriptive articles with reference to the Mayari field, and a few words about the Moa deposit, have also appeared3 It is the purpose of the present paper to give some account of the exploration of the Moa deposit arid to call attention to its commercial importance. Location. The Moa district is situated on the north coast of the Province of Oriente, which is the most easterly province of the

Jan 1, 1912

By Yoon T. Auck, Milton E. Wadsworth

Column leach studies of two low grade prophyry copper ores were made with variables of size, flow rate, pH, drainage rate and tempature. Evidence is presented to show that, in some types of ores, sulfide minerals block leaching channels and regulate the rate of dissolution of gangue constituents. Basic iron sulfates, dissolved by introducing acid, provide oxidizing agent in the form of ferric ion in the absence of oxygen. Ferric ion then acts to release copper from the ore. Oxygen up-take was found to increase with the lowering of the pH and to follow parabolic kinetics attributable to the precipitation of basic iron salts within the pore channels. Slow drainage of residual gravitational water can seriously retard oxygen up-take during oxidation for particles in the coarse sand range. A model is presented for dump leaching in which a reaction zone connected by channels to the surface of the ore particle moves topo-chemically during the course of the reaction.

Jan 1, 1973

By Samuel M. Cassidy, John A. Garcia

In some districts of the bituminous coal field the problem of constructing bulkheads to seal off water under pressure is becoming increasingly important. Recently this matter has been brought very much to the front by the loss of a large Illinois mine due to failure of a bulkhead that separated it from several old, flooded mines. As this great misfortune has provoked much inquiry about proper bulkhead design, it is felt that a description of the successful and extensive water-sealing practice at three mines that have different natural conditions will be of considerable interest to those connected with properties having a present or future water problem and to engineers that may have to design safe bulkheads of economical construction. These three mines are the Saxton and Dresser, near Terre Haute, Ind., and the Hegeler, near Danville, Ill. All three have water conditions that make it necessary to regularly seal off all worked-out sections of the mine, and there are considerably over a hundred bulkheads in each. AS far as the writers know, these three mines are the only ones in the bituminous coal fields of the United States with anything like so large a number of water seals and experience, although a number of other mines are known to have a few bulkheads. More detail will be included herein on the Saxton mine than on the others, as the writers are more familiar with it. General Mining System All three of the mines use the same general panel room-and-pillar system, which consists of rooms turned both ways off room entries and a solid block of coal left on all sides of the completed panel except on the cross-entry side, where a heavier pillar is pierced by two entries for haulage and air. On completion of the panel the two entries arc sealed and the panel is then isolated from the rest of the mine. Owing to water conditions, no pillars are pulled; recovery inside the panel barrier pillars is approximately 65 per cent.

Jan 1, 1938

By Samuel M. Cassidy, John A. Garcia

In some districts of the bituminous coal field the problem of constructing bulkheads to seal off water under pressure is becoming increasingly important. Recently this matter has been brought very much to the front by the loss of a large Illinois mine due to failure of a bulkhead that separated it from several old, flooded mines. As this great misfortune has provoked much inquiry about proper bulkhead design, it is felt that a description of the successful and extensive water-sealing practice at three mines that have different natural conditions will be of considerable interest to those connected with properties having a present or future water problem and to engineers that may have to design safe bulkheads of economical construction. These three mines are the Saxton and Dresser, near Terre Haute, Ind., and the Hegeler, near Danville, Ill. All three have water conditions that make it necessary to regularly seal off all worked-out sections of the mine, and there are considerably over a hundred bulkheads in each. AS far as the writers know, these three mines are the only ones in the bituminous coal fields of the United States with anything like so large a number of water seals and experience, although a number of other mines are known to have a few bulkheads. More detail will be included herein on the Saxton mine than on the others, as the writers are more familiar with it. General Mining System All three of the mines use the same general panel room-and-pillar system, which consists of rooms turned both ways off room entries and a solid block of coal left on all sides of the completed panel except on the cross-entry side, where a heavier pillar is pierced by two entries for haulage and air. On completion of the panel the two entries arc sealed and the panel is then isolated from the rest of the mine. Owing to water conditions, no pillars are pulled; recovery inside the panel barrier pillars is approximately 65 per cent.

Jan 1, 1938

By Louis A. Panek

Ground movements in the zone adjoining an active cave were measured at four sites in the San Manuel Mine. Measurements were made to detect extension and inclination, basic components of displacement, which can readily be duplicated by mine personnel using relatively simple equipment. The displacements demonstrated the development of a zone of strain relief surrounding the active cave, within which the ground tends to migrate toward the cave, and extension cracks develop tangential to the cave. This expansion of the ground surrounding an active cave can be exploited to promote future caving; it also creates special problems with respect to the design of an effective ground support system for mine openings in the production area.

Jan 1, 1981

By Gerald Edmunds

Although the phenomenon of season cracking is still imperfectly understood, there seems to be ample evidence that season cracks are propagated by the combined action of corrosion and a stress of either internal (residual) origin or external origin. The factors that influence season cracking may therefore be grouped according to corrosive media, nature of stress, and character of the material. Thus the important mass of evidence pointing to ammonia as the most frequently active corroding agent causing season - - cracking of brass has naturally led to the development of laboratory tests of a moderately accelerated character based upon ammonia together with auxiliary agents such as air, water vapor, and carbon dioxide as the corroding agent. Similarly, the knowledge that stress must be present has led to the use of externally applied and therefore accurately measurable stresses in laboratory testing. A companion paper(^)^ to the present one discusses the development of these test methods in our laboratories. The present paper discusses data bearing on factors concerning the nature of stress such as its magnitude and direction of application. It also deals extensively with the character of the brass, particularly in regard to the copper-zinc ratio and the structure as developed by mechanical work-

Jan 1, 1945

By George Bain

METHODS of mining building stone of any sort are planned to pro-duce as few fractures as possible, and present a strong contrast to methods of mining metallic ores, which must be crushed eventually and have fractures produced in as great profusion as possible. Shocks transmitted to a stone invariably make it more porous and more permeable and reduce its effective life, therefore methods of mining building stone involve as FIG. 1. THE SUPREME COURT BUILDING, WASHINGTON, D. C. This building illustrates the fine detail of workmanship, unprotected sharp corners and thin edges, and tall narrow columns characteristic of marble structures. These features require exceedingly coherent stone, and preservation of these features for decades or centuries demands many special quarrying precautions to keep absorption to 0.14 per cent or less, a detail not essential to stone for coarser architectural types. few shocks as possible. This is singularly true for marble because marble structures are intended to have long life, greater delicacy of line, more gracefulness and fineness of sculpture than those made from any other structural material (Fig. 1). So that delicate lines may remain in almost perfect preservation for decades, or even centuries, it is important

Jan 1, 1935

By A. G. Guy

Zinc vapor from a reservoir of liquid zinc maintained at lower temperatures was diffused into sets of copper-zinc alloys at 759° and 870° C and into sets of silver-zinc alloys at 650° and 700° C. Each set of ,four copper-zinc alloys consisted of pure copper and 90/10, 80/20, and 70/30 brass. Similarly the set of silver-base alloys consisted of specimens containing 0, 7, 15, and 20 pct Zn. Natural markers at the initial surfaces of the specimens ware "trapped" under a thin electroplate and their depth of burying was measured after diffusion. The ratio of diffusivities of the two components determined from these data and the chemical diffusion coefficient calculated by the Matano method agreed with previously reported results. The line of markers was irregular and was often discontinuous when a grain boundary was crossed. TECHNIQUES involving the vapor phase have been widely employed in studying diffusion phenomena in metals. Many investigators have evaporated the more volatile component from an alloy, but it is generally believed that the porosity created under these conditions interferes with adequate interpretation of the experimental results. The extensive work of Gertsriken6 has been criticized on this score. Accary1 found that the diffusion coefficient for de-zincification of brass is larger by a factor of five than that for zincification, although he attributed the difference to a higher vacancy concentration under conditions of dezincification. Balluffi and siegle2 thoroughly investigated the technique of adding a more volatile component to a less volatile base metal as a means for studying diffusion. They verified that no porosity forms in a brass under these conditions and that the diffusivities of the two components can be determined from observations of the motion of markers originally placed on the surface of the specimen. The mathematical analysis that they developed for treating the experimental data was modified in a later note, but essentially it involved using the graphical Boltzmann-Matano method that is customarily applied to solid-solid diffusion couples. The experimental method used in the present research was similar to that employed by Balluffi and Siegle except for two modifications. Balluffi and Siegle used alloy chips as the source of metal vapor. This procedure has the disadvantage that the concentration of solute at the surface of the specimen changes during the diffusion experiment as the alloy content of the chips is gradually decreased. This disadvantage was overcome by employing liquid zinc as the source of zinc vapor in a manner similar to that described by Herasymenko.9 There was then no limitation on the amount of solute usefully available, and several relatively large specimens could be diffused in a given experiment. The second modification was the use of natural markers on the surface of the specimen rather than larger, artificial markers, such as the alumina powder employed by Balluffi and Siegle. It was expected that the fine, natural markers would permit more precise measurement of the buried interface as in the case of ordinary sandwich specimens.10 EXPERIMENTAL The experiments were designed so that zinc from the vapor phase would maintain a constant zinc content at the surface of pure copper (or silver) and

Jan 1, 1960

By E. G. Leonardon

The object of this paper is to describe briefly the practical results obtained in several problems of civil engineering by resistivity measurements of the underground. It is intended for the mining engineer, as well as for the construction engineer; the stratigraphical problems discussed are general and frequently are encountered in mining exploration. Resistivity measurements have been used in mining and oil exploration for a number of years.' Their introduction in the field of civil engineering, on the contrary, is rather recent. It was applied for the first time in the spring of 1928 near Littleton, N. H., in the survey of two dam sites for the New England Power Assn.2 Since then, the geophysical firm with which the author is connected has had an opportunity to develop this field of activity, and more than 20 investigations at dam and tunnel sites have been carried out in the United States and Canada. A part of this work has been verified by underground or drilling exploration. This paper deals with but a few of the results, which we are permitted to make public now. The theoretical and technical sides of the processes employed will not be discussed; they have already been described in various technical publications. A few general points will be mentioned, to make clear the practical examples given. Resistivities OF the Rocks The surveys are based on the measurement of the specific resistance of the rocks. This resistivity is the electrical resistance of a cylinder of

Jan 1, 1932

By J. G. Richardson

The performance of laboratory water floods is compared with the flooding behavior calculated by the Buckley-Leverett techniques from steady-state relative permeability-saturation relations. Both the steady-state and unsteady-state experiments were conducted on the same sand-packed column. Relative permeabilities were calculated by the Welge technique from the unsteady-state waterflooding displacement experiments and compared with those measured by steady-state techniques. An evaluation of the various calculation procedures was made. It was demonstrated that steady-state relative permeabilities could be used to calczcJate waterflood performance. INTRODUCTION To calculate the waterflooding behavior of a given reservoir, relative permeability-saturation relations of the reservoir rock are required. These relative permeabilities are commonly measured on core samples by steady-state experiments such as the Penn State technique.' The relative permeabilities obtained in steady-state experiments are calculated from oil and gas flow rates and pressure drops measured under conditions of equilibrium distribution of oil and water in the pore spaces with slow approach to equilibrium. On the other hand, in water floods the water saturation at a given point changes rapidly with time as the flood front passes. Extensive research2 has shown that the steady-state relative permeabilities to oil and water are independent of the rate of flow and the fluid viscosities. Research has also demonstrated that the waterflooding performance of homogeneous sands uniformly contacted by water is independent of rate when capillary pressure gradients, which are important in short laboratory columns, are made negligible. However, there is little experimental data in the literature comparing relative permeabilities calculated from steady-state flow experiments with those calculated from flooding experiments. In this paper, the production data of two water floods and the relative permeabilities calculated from a series of steady-state experiments on an unconsolidated sand column are presented along with the comparisons calculated by the Buckley-Leverett and by the Welge techniques. The purpose of this study was to determine if steady-state relative permeabilities could be used to predict the waterflooding performance. This study also permitted an evaluation of the Buckley-Leverett and Welge calculation procedures and allowed an insight into the nature of microscopic displacement of oil by water. EXPERIMENTAL APPARATUS AND PROCEDURE The apparatus used in this investigation was a Lucite column 1 ft long and 11/2 in. in diameter. A drawing of the apparatus is shown in Fig. 1. Six pressure taps were evenly spaced along the top of the column to measure the oil pressures. Three pressure taps fitted with small porous disks were spaced along the side of the column to measure water pressure. Water was admitted to the inflow face of the sand through a porous disk while oil was admitted through a hole in the porous disk and distributed to the face of the sand by grooves machined in the porous disk. Retainer screens of 325-mesh stainless steel were cemented over the inlet and outlet ports and the pressure taps to prevent loss of sand. The column was packed with a clean dry sand all of which was finer than 200 mesh. Next, the sand was saturated with a solution of 150,000 ppm sodium chloride solution. The column was weighed dry and water-saturated to obtain data for the calculation of the pore volume. A 151-cp oil was then injected into

Jan 1, 1958

By William E. Hubbard

During the last decade the known reserves of petroleum in the United States have increased from about five billion to over thirteen billion barrels. From the standpoint of public welfare the existence of these known reserves presents an undeniably favorable picture, but viewed from the position of many a harassed operator the blessing has not always been considered an unmixed one. Along with this increase in excess reserves, curtailment of production has come into being as a matter of necessity and the principle of proration as a matter of equity. As a practical matter it has been considered necessary to curtail the production of old wells as well as that of new wells in a pool. The right of new pools to produce has been recognized, and the allowable for them has come partly from increased market demand and largely from the allowables already enjoyed by the developed pools. The natural result—a downward trend in daily per-well allowables—has been especially felt by Texas operators. This trend may be illustrated by Table 1, which comprises the five active areas in Texas, and from which may be noted the following: 1. The average daily allowable per well has decreased about 53 per cent in three years. 2. Of the 184,000-bbl. increase in total allowable for the five areas, 29,000 bbl. came from the increase in state demand and 165,000 from the combined allowables of the remaining pools in the state.

Jan 1, 1937