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By J. A. Hafford, J. K. Kerver, J. G. Richardson, P. M. Blair, J. S. Osoba

This paper presents the results of laboratory measurements of relative permeabilities to oil and gas on small core samples of reservoir rock by five methods, and describes the influences of such factors as boundary effect, hysteresis, and rate upon these measurements. The five methods used were the "Penn State," the "single core dynamic," the "gas drive," the "stationary liquid," and the "Hassler" techniques. In those methods in which the results are subject to error hecause of the boundary effect, the error may be minimized hy the use of high rates of flow. In order to avoid complexities introduced by hysteresis, it is necessary to approach each saturation unidirectionally. Observed deviations of relative permeabilities with rate can be explained as a manifestation of the boundary effect, and disappear as the boundary effect vanishes. The results indicate that all five methods yield essentially the same relative permeabilities to gas. Of the four methods applicable to the determination of relative permeability to oil, three, the Penn State, single core dynamic, and gas drive, gave relative permeabilities to oil which were in close agreement. The Hassler method gave relative permeabilities to oil which were consistently lower than the results obtained by the other methods. INTRODUCTION The relationship between the effective permeability of a reservoir rock to each of the fluids flowing through it and the corresponding fluid saturation is an important characteristic of the reservoir rock. Knowledge of this characteristic is and gas reservoirs and of the ultimate recovery to be expected extremely important in the prediction of the behavior of oil under various operating conditions. These effective permeabilities are usually expressed as the "relative permeability" to a fluid phase, defined as the ratio of the effective permeability to the permeability of the rock to a single phase at 100 per cent saturation. Relative permeability-saturation relations are not the same for all kinds of reservoir rock, but may vary from formation to formation, and within the different portions of a heterogeneous formation. In studying the performance of a specific reservoir, it is necessary, then, that the relative permeability characteristics of the individual portions of the reservoir be measured. These measurements may be made in the laboratory on small core samples from the reservoir. Various techniques have been proposed for the measurement in the laboratory of relative permeability-saturation relations. In varying degree, difficulties attend the use of all of the methods which have been proposed. It is the purpose of this paper to discuss the factors which influence the measurement of relative permeability, the difficulties encountered in several methods, and to present comparative results obtained by the use of various techniques. FACTORS WHICH INFLUENCE THE MEASUREMENT OF RELATIVE PERMEABILITY It is necessary that the relative permeability data measured in the laboratory yield the same relative permeability-saturation relationships that would govern the flow of fluids through the sample if it were to occupy its original position in the reservoir. Since the core sample upon which the laboratory measurements are made is not surrounded by similar core material as it was in the reservoir, an error in measuring the relative permeabilities may arise from the "boundary effect" which results from a discontinuity in capillary properties of the system at the effluent end of the core. Again, the rates of

Jan 1, 1951

By Dwight H. Seely, Louis R. Records

A process for low-temperature dehydration of natural gas utilizing Joule-Thomson effect in expansion through a throttling orifice has been tested in a full-scale field installation. The results of these tests are presented in the form of performance curves from which the process may be easily evaluated. The effect of separation temperature on condensate recovery from the process is also shown. INTRODUCTION The transportation of natural gas from producing well to the consumer has always encountered the problem of hydrate prevention. This problem has become increasingly important in the past ten years due to the rapid increase in produced gas volumes, production pressures, transportation pressures and distance from producing wells to consumer. Natural gas, as normally produced from gas or gas-condensate wells, is saturated with water vapor at well-head conditions of temuerature and pressure. The solution of the hydrate problem require; but one basic process — dehydration of the gas to a water content which will result in a water dew-point below the minimum temperature to be encountered from the producing well to the point of consumption. Much of the recent development of gas and gas-condensate reserves in the Gulf Coast Area has been in locations which are accessible only by water. High well-head pressures, pipeline construction and maintenance costs and the desirability of final central gas-condensate separation facilities have stimulated the development of dehydration equipment which can be installed at each well and which will permit hydrate-free transportation of both gas and condensate in the same line to central facilities. There are four types of natural gas dehydration processes now used: 1. Adsorptive processes. 2. Absorptive processes. 3. Chemical reaction processes. 4. Refrigeration processes. The first three of these processes are indirect in that they require use of adsorbents, absorbents or reactive chemicals. These materials require regeneration and part of the total gas stream is consumed in the regenerative process. Indirect processes have a wide range of flexibility as defined by allowable operating pressure and temperature, but most are not easily adapted to automatic operation. The refrigeration process described in this paper was designed for installation at the producing well-head. It requires no regenerative cycle and with normal well-head temperatures no external source of heat. The flexibility of this process is limited only by the pressure drop which may be allowed between well-head and transportation line. THEORY There are three basic physical concepts involved in the low temperature dehydration process. These are: 1. Formation of hydrocarbon hydrates. 2. Joule-Thompson effect resulting from the expansion of gaseous mixtures through a throttling orifice. 3. The equilibrium composition characteristics of water vapor and gaseous hydrocarbon mixture.. The chemical composition and physical structure of hydrate; have been described by several investigators.3,4,5,10 Specific conditions of temperature, pressure and composition as well as the requirements for turbulence and presence of free water necessary for hydrate formation have been described by Katz.6 Natural gas hydrates, as they are found in plugged gas pipe lines, have the appearance of packed snow. The mass of these hydrates has low continuous porosity and permeability. Joule-Thomson effect. or the reduction in temperature which occurs when natural gas is throttled throusll a restrictive orifice, is the basic phenomenon which permits efficient use of refrigeration for the purpose of dehydrating natural gas. Joule-Thomson coefficients for gafeous mixture; of methane with ethane and with butane have been reported by Buder.-I~olzer, Sage and Lacey.2 Brown1 predicted temperature drops for pressure drops from enthalpy-entropy calculations. Aside from this work there were no fundamental data found which would be applicable to natural gas mixtures of varying spe-

Jan 1, 1951

By Norris Johnston, Carrol M. Beeson

The gravimetric-vacuum distillation method was developed to permit rapid and accurate determinations of the oil-water ratios of small samples or sands containing little oil. In addition, the samples usually are so well cleaned and so little altered by the distillation at reduced pressure that rapid estimations of other physical properties may be made with the evacuated cores. Requiring only elementary glass-blowing technique, the distilling tubes and traps used in determining oil-water ratios were easily fashioned from the usual glassware. A sketch and description are given of the necessary apparatus, including the cylindrical electrical heaters. The procedure, requiring about 40 min., consists in raising the temperature and maintaining it between 675' and 725°F. for at least 10 min. while the pressure is held between I and 2 mm. Hg. The fluids condensed in the trap (cooled by a mixture of kerosine and solid carbon dioxide) are separated in a centrifuge and the volume of water is recorded. Determination of changes in weight with an analytical balance of all parts of the apparatus permits computation of weight of oil distilled and total weight of oil recovered. Introduction In determining the oil-water ratios of core samples, distillation at atmospheric pressurel-5 has proved to be sufficiently reliable for samples containing moderate quantities of oil. Since small samples and sands with little oil are encountered, how- ever, it appeared advisable to develop a method that would be applicable under these circumstances. Thegravimetric-extraction procedure1,6-9 undoubtedly is very reliable and could be used in all tests, but the time consumed in the determination would often delay field operations. This would be especially true when dealing with tight sands or viscous oils, both of which retard the extraction process. Accordingly, the gravimetric-vacuum distillation method was developed in order to combine the good features of both of the older methods; that is, accuracy and speed. By reducing the pressure, it was found possible to perform the distillation at a temperature that permits the use of glass apparatus, all parts of which can be weighed on an analytical balance. Thus, the fluids may be removed quickly from the core, the water is readily trapped and measured, and the loss in weight of the core is easily determined. In addition, the total weight of material condensed in the distilling tube and in the trap provides a method of determining the oil-water ratio that is practically independent of the one involving the loss in weight of the sample. The use of vacuum not only permits as much accuracy as does the gravimetric-extraction process, but it actually allows an increase in speed over the atmospheric-distillation method, because of the time required to cool the metal pots from about 1200°F. between runs. More important yet, the innovation makes possible the almost immediate reporting of permeability, and saturation, which is impossible

Jan 1, 1946

By Dwight H. Seely, Louis R. Records

A process for low-temperature dehydration of natural gas utilizing Joule-Thomson effect in expansion through a throttling orifice has been tested in a full-scale field installation. The results of these tests are presented in the form of performance curves from which the process may be easily evaluated. The effect of separation temperature on condensate recovery from the process is also shown. INTRODUCTION The transportation of natural gas from producing well to the consumer has always encountered the problem of hydrate prevention. This problem has become increasingly important in the past ten years due to the rapid increase in produced gas volumes, production pressures, transportation pressures and distance from producing wells to consumer. Natural gas, as normally produced from gas or gas-condensate wells, is saturated with water vapor at well-head conditions of temuerature and pressure. The solution of the hydrate problem require; but one basic process — dehydration of the gas to a water content which will result in a water dew-point below the minimum temperature to be encountered from the producing well to the point of consumption. Much of the recent development of gas and gas-condensate reserves in the Gulf Coast Area has been in locations which are accessible only by water. High well-head pressures, pipeline construction and maintenance costs and the desirability of final central gas-condensate separation facilities have stimulated the development of dehydration equipment which can be installed at each well and which will permit hydrate-free transportation of both gas and condensate in the same line to central facilities. There are four types of natural gas dehydration processes now used: 1. Adsorptive processes. 2. Absorptive processes. 3. Chemical reaction processes. 4. Refrigeration processes. The first three of these processes are indirect in that they require use of adsorbents, absorbents or reactive chemicals. These materials require regeneration and part of the total gas stream is consumed in the regenerative process. Indirect processes have a wide range of flexibility as defined by allowable operating pressure and temperature, but most are not easily adapted to automatic operation. The refrigeration process described in this paper was designed for installation at the producing well-head. It requires no regenerative cycle and with normal well-head temperatures no external source of heat. The flexibility of this process is limited only by the pressure drop which may be allowed between well-head and transportation line. THEORY There are three basic physical concepts involved in the low temperature dehydration process. These are: 1. Formation of hydrocarbon hydrates. 2. Joule-Thompson effect resulting from the expansion of gaseous mixtures through a throttling orifice. 3. The equilibrium composition characteristics of water vapor and gaseous hydrocarbon mixture.. The chemical composition and physical structure of hydrate; have been described by several investigators.3,4,5,10 Specific conditions of temperature, pressure and composition as well as the requirements for turbulence and presence of free water necessary for hydrate formation have been described by Katz.6 Natural gas hydrates, as they are found in plugged gas pipe lines, have the appearance of packed snow. The mass of these hydrates has low continuous porosity and permeability. Joule-Thomson effect. or the reduction in temperature which occurs when natural gas is throttled throusll a restrictive orifice, is the basic phenomenon which permits efficient use of refrigeration for the purpose of dehydrating natural gas. Joule-Thomson coefficients for gafeous mixture; of methane with ethane and with butane have been reported by Buder.-I~olzer, Sage and Lacey.2 Brown1 predicted temperature drops for pressure drops from enthalpy-entropy calculations. Aside from this work there were no fundamental data found which would be applicable to natural gas mixtures of varying spe-

Jan 1, 1951

By G. A. Croes, N. Schwarz

The dimensionless groups, to which the variables that govern the displacement of oil from reservoirs by liquids can be combined, are derived. Three types of displacement are considered, viz. cold-water drive, hot-water drive and solvent injection. The derivation of the dimerzsionless groups is carried out by means of the relevant basic equations (in-spectional analysis). The resulting sets of groups are afterwards completed by means of dimensional analysis. The form of the groups is given in such a way that they can be adapted to suit the various boundary conditions that are encountered in practice. The physical meaning of the groups is discussed. They have all been brought together on a chart, from which their mutual relation and their corresporzdence to related dimensionless groups in common use in other engineering sciences can be read off. The limitations of dimensionally scaled model experiments as a useful tool for studying liquid flow in porous media, as occurring in oil reservoirs, are discussed. The use of models to study fluid mechanics has an appeal for everyone endowed with natural curiosity. What active boy has not played with ship and airplane models, or crude models of dam and drainage systems Even in the most advanced technical engineering, such models play a fundamental and indispensable role. "And yet in few departments of the physical sciences is there a wider gap between theory and practice, between scientific knowledge and the state of art, than in the use of models to study hydrodynamic phenomena." Garrett Birkhoff1 INTRODUCTION Laboratory displacement experiments are extensively used to investigate, directly or indirectly, the production behavior of petroleum reservoirs. Such experiments are representative of the reservoirs as a whole, if they are carried out with models that are "properly scaled." The performance of oil reservoirs is governed by the values of a number of variables, which can be combined to dimensionless groups. Two general methods are available for the derivation of these groups. In the first of these, dimensional analysis, combination of the variables is done essentially by trial and error. Its only premise is knowledge of the complete set of relevant variables. In the second method, inspectional analysis, the dimensional homogeneity of the equations describing the behavior of the system to be studied is used. The resulting dimensionless groups can be divided into: (a) independent (variable) groups, such as dimensionless length, time, etc.; (b) dependent groups, giving the dimensionless form of the variables, such as recovery and pressure, that can, at least in principle, be measured during an experiment; (c) similarity groups, which are independent constant groups, such as ratio of length to height of the reservoir and ratio of

Jan 1, 1957

By Gordon I. Gould

The treatment of quicksilver ores to extract the metal, for centuries one of the fundamentally simpler metallurgical operations, has undergone few if any material changes during the past iew decades other than improvement and change of type of equipment used. Of almost universal application and as the seldom deviated from process, the roasting method is still considered superior to chemical metallurgy. Likewise, roasting of the crude ore without previous beneficiation continues to be standard practice, although some successful operations have employed concentration prior to roasting. The roasting process has been carried out in a variety of equipment, devised for different tonnage capacities, to treat "special" ores, and to satisfy an inventive notion of the particular builder, but during the past 25 years there has been one outstanding change in roasting equipment. This change, though neither originating in nor confined to the United States, has probably been developed and applied to a far greater extent in this country than in any other mercury-producing country of the world. The change from manually or gravity operated furnaces, mostly huge brickwork affairs justified largely by simplicity, lack of power and mechanical requirements, and occasionally by excellent metallurgical results, to mechanical furnaces, began actively during World War I under the stress of requirements for in- creased production, a shortage of labor, 2nd other factors to be brought out later. During the twenties the change to mechanical furnaces became nearly complete at American mines with the development of several types, the rotary furnace predominating. During the thirties, and the period of low prices in the early part of this period, few changes were made other than mechanical improvements and an almost complete acceptance of two types: the rotary furnace and the hearth or Wedge furnace. These two types have been developed to a high degree of metallurgical efficiency, have proved to be mechanically simple and have far greater flexibility and lower operating costs than pre-World War I furnaces. Of the two types the rotary is the more popular, about 30 rotaries having been in operation in the United States in 1943 as compared with about six hearth-type furnaces. The units of smaller capacity for roasting mercury ores have almost without exception been indirectly fired, such distinction being commonly accepted as the difference between retorts and furnaces, which are fired directly. The difference between indirect and direct firing obviously permits of quite different conditions surrounding the ore being roasted in relation to the chemical reaction to take place. In the indirect-fired unit the ore is contained within the body of the retort in a stagnant if not completely oxygen-impoverished atmosphere. In the direct-fired furnace the ore is in contact with the gases of combustion, which may easily (if not too easily) be supplied with an excess of

Jan 1, 1944

By T. R. Ingraham

The thermal decomposition of Nickel (II) sulfate was examined by determining the total pressure of SO3, SO2, and O2 developed over a sample when it was heated in an evacuated system fitted with a Pyrex-bellows mercury manometer. The equilibrium pressures were combined with previously published data on the oxide and sulfide systems to establish a predominance volume diagranz for the Ni-S-O system over the normal range of roasting temperature and gas composition used in the treatment of nickel minerals. The protective coating of NiSO4 which forms on the oxide during roasting, and which causes the sulfation reaction to almost cease, may be disengaged readily by temperature cycling. When nickel sulfide is roasted in air, either nickel sulfate or nickel oxide may be formed by altering the experimental conditions. Because of the differing stabilities of various metal sulfates and oxides, possibilities exist for separating some of the constituents of mineral mixtures by the technique of selective sulfation and oxidation roasting. The experimental information required to make reasonable predictions of the possibilities of this technique is incomplete and, in some cases, in conflict. As part of a general program of providing some of the required information, a study EXPERIMENTAL Materials, Apparatus, and Procedure. Fisher certified reagent-grade nickel sulfate hexahydrate was used in the source material for both nickel sulfate and nickel oxide. The manufacturer's analysis indicated: 0.001 pct Fe, 0.005 pct Cu, 0.003 pct Co, 0.001 pct C1, other 0.15 pct. The material was dehydrated, before use, by heating at 420°C for 5 hr. The oxide was prepared by roasting the sulfate in an open tray in a muffle furnace for 10 hr at950°C. Preliminary experiments which were made by thermogravimetric analysis and X-ray diffraction analysis established that only one crystal form of nickel oxide and one of nickel sulfate were involved in the equilibrium shown in Eq. [I]. The apparatus used in the experiments was described previously.1,3 The main feature is a corrosion-resistant, flexible Pyrex bellows which is used to protect the mercury in a u-tube manometer. Before a run was begun, the apparatus was washed thoroughly with hot hydrochloric acid and water and dried by heating under vacuum. The mixed sulfate -oxide sample was contained in a platinum bat rest-

Jan 1, 1967

By Arthur S. Dwight

We author of this historical chapter will perhaps be criticized for limiting his subject to the history of the blast furnace in lead smelting, and especially to the part it played in the great custom ore-smelting business which for three decades or more was the means of opening up vast mineral treasures and practically dominated the mining industry in the Rocky Mountain region of the United States, in Mexico and in Canada. The men of that era shared the romance and the thrills of mining, and bore their part as pioneers in the building of the great West. The present writer was too young to participate in the first of the three decades mentioned, but immediately thereafter came under the apprenticeship of some of the men who had worked out the early metallurgical problems of the industry, became personally acquainted with most of the others of that group, heard the tales of early experiences, successes and failures, the gossip of the frontier and mining camps, from all of which there remain embedded in his mind clear impressions of the outstanding personalities of that time. That is the background against which the fifty years of intimate contact with the mining and smelting business and his own experiences as metallurgist stand out in his memory, and it is hoped that the gentle reader may understand and approve his desire to rescue from comparative oblivion the fundamentally valuable results accomplished by these fathers of the industry. It will be the purpose of this chapter first to narrate the general history of the growth of the industry; second, to pay tribute to some of the pioneer metallurgists, and third, to discuss some of the salient points of the metallurgical practice at different periods, to illustrate the technical progress of the art. The series of eight Annual Reports of Rossiter W. Raymondl,† U. S. Commissioner of Mining Statistics from 1869 to 1876, contain most of the available information about the early smelting operations in the Rocky Mountain region, and much is in the early volumes of the Transactions of the American Institute of Mining Engineers. The monograph by S. F. Emmons2 though not published until 1886, contained an elaborate description of the smelting works operating in 1879. Otto H. Hahn3 wrote a valuable paper in 1883, on smelting prac-

Jan 1, 1937

By Norris Johnston, Carrol M. Beeson

The gravimetric-vacuum distillation method was developed to permit rapid and accurate determinations of the oil-water ratios of small samples or sands containing little oil. In addition, the samples usually are so well cleaned and so little altered by the distillation at reduced pressure that rapid estimations of other physical properties may be made with the evacuated cores. Requiring only elementary glass-blowing technique, the distilling tubes and traps used in determining oil-water ratios were easily fashioned from the usual glassware. A sketch and description are given of the necessary apparatus, including the cylindrical electrical heaters. The procedure, requiring about 40 min., consists in raising the temperature and maintaining it between 675' and 725°F. for at least 10 min. while the pressure is held between I and 2 mm. Hg. The fluids condensed in the trap (cooled by a mixture of kerosine and solid carbon dioxide) are separated in a centrifuge and the volume of water is recorded. Determination of changes in weight with an analytical balance of all parts of the apparatus permits computation of weight of oil distilled and total weight of oil recovered. Introduction In determining the oil-water ratios of core samples, distillation at atmospheric pressurel-5 has proved to be sufficiently reliable for samples containing moderate quantities of oil. Since small samples and sands with little oil are encountered, how- ever, it appeared advisable to develop a method that would be applicable under these circumstances. Thegravimetric-extraction procedure1,6-9 undoubtedly is very reliable and could be used in all tests, but the time consumed in the determination would often delay field operations. This would be especially true when dealing with tight sands or viscous oils, both of which retard the extraction process. Accordingly, the gravimetric-vacuum distillation method was developed in order to combine the good features of both of the older methods; that is, accuracy and speed. By reducing the pressure, it was found possible to perform the distillation at a temperature that permits the use of glass apparatus, all parts of which can be weighed on an analytical balance. Thus, the fluids may be removed quickly from the core, the water is readily trapped and measured, and the loss in weight of the core is easily determined. In addition, the total weight of material condensed in the distilling tube and in the trap provides a method of determining the oil-water ratio that is practically independent of the one involving the loss in weight of the sample. The use of vacuum not only permits as much accuracy as does the gravimetric-extraction process, but it actually allows an increase in speed over the atmospheric-distillation method, because of the time required to cool the metal pots from about 1200°F. between runs. More important yet, the innovation makes possible the almost immediate reporting of permeability, and saturation, which is impossible

Jan 1, 1946

By J. K. Kerver, J. S. Osoba, J. G. Richardson, P. M. Blair, J. A. Hafford

This paper presents the results of laboratory measurements of relative permeabilities to oil and gas on small core samples of reservoir rock by five methods, and describes the influences of such factors as boundary effect, hysteresis, and rate upon these measurements. The five methods used were the "Penn State," the "single core dynamic," the "gas drive," the "stationary liquid," and the "Hassler" techniques. In those methods in which the results are subject to error hecause of the boundary effect, the error may be minimized hy the use of high rates of flow. In order to avoid complexities introduced by hysteresis, it is necessary to approach each saturation unidirectionally. Observed deviations of relative permeabilities with rate can be explained as a manifestation of the boundary effect, and disappear as the boundary effect vanishes. The results indicate that all five methods yield essentially the same relative permeabilities to gas. Of the four methods applicable to the determination of relative permeability to oil, three, the Penn State, single core dynamic, and gas drive, gave relative permeabilities to oil which were in close agreement. The Hassler method gave relative permeabilities to oil which were consistently lower than the results obtained by the other methods. INTRODUCTION The relationship between the effective permeability of a reservoir rock to each of the fluids flowing through it and the corresponding fluid saturation is an important characteristic of the reservoir rock. Knowledge of this characteristic is and gas reservoirs and of the ultimate recovery to be expected extremely important in the prediction of the behavior of oil under various operating conditions. These effective permeabilities are usually expressed as the "relative permeability" to a fluid phase, defined as the ratio of the effective permeability to the permeability of the rock to a single phase at 100 per cent saturation. Relative permeability-saturation relations are not the same for all kinds of reservoir rock, but may vary from formation to formation, and within the different portions of a heterogeneous formation. In studying the performance of a specific reservoir, it is necessary, then, that the relative permeability characteristics of the individual portions of the reservoir be measured. These measurements may be made in the laboratory on small core samples from the reservoir. Various techniques have been proposed for the measurement in the laboratory of relative permeability-saturation relations. In varying degree, difficulties attend the use of all of the methods which have been proposed. It is the purpose of this paper to discuss the factors which influence the measurement of relative permeability, the difficulties encountered in several methods, and to present comparative results obtained by the use of various techniques. FACTORS WHICH INFLUENCE THE MEASUREMENT OF RELATIVE PERMEABILITY It is necessary that the relative permeability data measured in the laboratory yield the same relative permeability-saturation relationships that would govern the flow of fluids through the sample if it were to occupy its original position in the reservoir. Since the core sample upon which the laboratory measurements are made is not surrounded by similar core material as it was in the reservoir, an error in measuring the relative permeabilities may arise from the "boundary effect" which results from a discontinuity in capillary properties of the system at the effluent end of the core. Again, the rates of

Jan 1, 1951

By James Aston

Three years ago the writer presented a paper on the trend of development in the wrought iron industry,' wherein was described a process in the development of which he has been a factor, which at that time had passed through several years of progressive experimental development but which had not then been put upon a commercial scale of operation. The present paper deals with two years of observation and experience in the commercial operation of a plant by the A. M. Byers Co. at Warren, Ohio. It will not enter into the controversial field of the relative merit of wrought iron and steel in various classes of service, nor will it elaborate upon the characteristic services or fields of utility to which wrought iron is particularly adapted. It is sufficient to state that the wrought iron industry is upon a substantial basis and that the material finds service in pipe, where its advantages are in superior corrosion, fatigue, welding and threading qualities; in bar iron for staybolts, engine bolts, and rivets, demanding maximum service against corrosion and fatigue; in plates for corrosion service; and in chains, because of welding and shock-resisting characteristics. In short, ability to withstand the stresses of shock and vibration, or the ravages of corrosion, to hold protective coatings, and to give maximum efficiency in welding, are its features of relative superiority. If these features were not well recognized, the wrought iron industry would have shrunk to insignificance in the face of high costs and acknowledged limitations in manufacture. To charge that this industry is built upon a structure of assumption, psychology, and improperly weighed evidence is an impeachment of the integrity or belittling of the powers of observation of users through many centuries of service experiences. In a history which extends to prehistoric time, and which is linked up with the earliest records of ferrous products, the dominant method of manufacture, as we have known it for little over a century, occupies a very small niche in the span of years that mark production and use of wrought iron. Puddling, the outstanding manufacturing method of

Jan 1, 1929

By W. R. Atkins

The Negaunee mine is at the east end of the Marquette Range, in the city of Negaunee, on the Upper Peninsula of Michigan. Iron ore was first discovered on this property in 1883 by diamond drilling. A shaft was sunk soon afterward. and the mine has been worked continuously ever since. The total shipments from 1887 to Jan. I, 1945, were 20,417,587 long tons. The mine was taken over by the present operators, The Cleveland-Cliffs Iron Co., in 1903. During the past four years, 1941 to 1944 inclusive, the property has produced an average of nearly a million tons a year, and has employed more than 400 men. Geology The ore body at the Negaunee mine lies in a large syncline dipping about 15° to the west, the ore coming to ledge at the east end of the trough. The ore occurs in the Negaunee formation of the middle Huronian age, which consists of ferruginous cherts and slates through which intrusions of diorite have occurred. Although these intrusions of diorite have an important bearing on the formation of ore on the range, they are not important in this ore body. Some faulting has taken place along the diorite intrusions, or dikes as they are called locally, and also other faults are known to exist across the formation. These faults do not complicate either mining or development of the ore body. The footwall consists of jasper underlain with Siamo slate; the hanging wall is jasper and ferruginous chert. Fig. I shows a typical cross section of the ore body. The ore body is quite regular, about 120 ft. thick in the middle of the syncline and thinning out toward both sides of the fold. Its width ranges from 400 to 800 ft., the average being about 600 ft. The footwall is uniform in dip and strike, but irregular lenses of ore often extend 50 to 75 ft. up into the overlying jasper capping. Method of Mining Ore in the Negaunee mine has been mined by top slicing almost exclusively since 1903 This method of mining has been employed because it is especially adapted to the size and shape of the Negaunee ore body, and to the soft, sticky nature of the ore as well as the generally soft, broken jasper capping. Development The ore body has been developed from six different levels with intervals varying between loo and 125 ft. On the average, the dip causes a horizontal offset of 350 ft. per level, and under these circumstances it has been necessary to carry on considerable development in rock to make available the ore lying along the north and east footwalls. This is not as disadvantageous as might be supposed, because of reduced pressure and the accompanying saving in maintenance costs. The development of the

Jan 1, 1949

By Walter Crafts, C. M. Offenhauer

IN the course of study of the heat-treatment of low-alloy steels, the behavior of alloy carbides at subcritical temperatures was found to vary from that indicated by published investigations. In order to establish the ranges of formation of carbides in low-chromium steels, a series of steels containing up to 0.60 per cent carbon and 7.5 per cent chromium has been investigated with respect to the type of carbide formed after quenching and tempering at subcritical temperatures. The types of carbide formed as products of austenite transformation to pearlitic and pseudomartensitic structures have also been determined. There have been numerous investigations of the carbides in chromium steels and diagrams of the iron-chromium-carbon system.1 Westgren, Phragmén and Negresco2 identified the following carbides in chromium steels: [Cementite Fe3C (containing up to about 15 per cent Cr) Trigonal carbide Cr7C3 (containing up to about 55 per cent Fe) Cubic carbide Cr4C (or Cr23C3) (containing up to about 25 per cent Fe) Orthorhombic carbide . Cr3C2 (containing only a few per cent Fe)] The most complete information on the iron-chromium-carbon system was supplied by Tofaute, Sponheuer and Bennek3 and by Tofaute, Küttner and Büttinghaus.4 By means of dilatometric and microscopic studies, sections of the diagram were established. This diagram showed the presence of the special carbide Cr7Ca in steels containing about 2.5 per cent to 12 per cent chromium in low-carbon steels and from about 5 to 20 per cent chromium in r per cent carbon alloys from A1 to room temperature. The present investigation has shown that a carbide inversion from Fe3C to Cr7Ca occurs in chromium steels containing more than about 1 per cent chromium after hardening and tempering at subcritical temperatures above about 500°C. The type of carbide observed to be more stable in quenched and tempered specimens was also found to be produced by direct austenite transformation in corresponding ranges of temperature and composition. EXPERIMENTAL PROCEDURE The steels used in these experiments were made in magnesia-lined crucibles in high-frequency furnaces and were poured into 2-in. ingots. The ingots were forged into 1-in. round bars, and all heat-treatments were conducted on specimens of this section .size. Sections of the bar stock 8 in. long were hardened in air, oil or water depending on the composition, after heating to a temperature sufficiently high to dissolve the carbides. The low-carbon and low-chromium steels were not entirely martensitic after quenching, and contained some ferrite and pseudomartensite. No pearlite was observed in the microstructures after auenchine. The quenched bars were cut into

Jan 1, 1942

By C. C. Singleterry, D. L. Katz

The critical phenomena have been studied during the past century but our knowledge of the critical temperatures and pressures of complex hydrocarbon mixtures still is very limited. The critical temperatures and pressures of pure substances have been examined in large numbers120 and in great detail.11.17 No experimental determinations of the critical phenomena have been reported on such complex hydrocarbon systems as a reservoir fluid. The critical temperature is defined by Taylor18 as follows: "there is some temperature for each gas above which the gas cannot be liquefied. This temperature is called the critical temperature." The critical pressure of a pure substance is the vapor pressure at the critical temperature. It should be noted that these definitions refer to a given substance in the pure state and do not mean that the pure substance cannot be liquefied in the presence of a second constituent. The normal procedure for obtaining the critical temperature of a substance is to heat it in a glass tube 1,20 under pressure until the meniscus between the liquid and vapor phase disappears, although other methods, especially for mixtures, have been used.13,14 However, when considering oil and gas reservoirs, it is more enlightening to consider a critical phenomenon that occurs when a mixture of oil and gas are compressed at a reservoir temperature until the meniscus disappears because the two phases become equal in composition. This conception, along with erroneous applications of the definition of the critical phenomena of a pure substance to that pure substance when it is part of a complex mixture, has caused confusion even among persons familiar with the classical theories. The purpose of this paper is to discuss the critical phenomena of pure substances and mixtures and to report experimental data on a mixture of

Jan 1, 1939

By Emil Gathmann

Steel as it is poured, or teemed, into the mold for forming the ingot may be broadly separated into two divisions; i.e., effervescing or gassy steel, also termed evolution steel, and non-effervescing or killed steel, also termed solution steel. Between these primary divisions there are various types having the characteristics of both divisions but really nut belonging to either; such steels are termed semi-piping, rising, or wild, as the type may be. True effervescing steel should contain large volumes of gases, which are evolved while the metal is being teemed from the ladle nozzle into the mold, and continue to escape while the temperature of the steel is falling prior to its solidification the top of the ingot remaining liquid, due to the evolution of gases, until an ingot skin of considerable thickness has been formed. These gases consist principally of hydrogen, carbon monoxide, nitrogen, and ammonia. It is generally understood that nitrogen gases are the first evolved and these form the skin blowliolcs, troublesome at times, in the solidifying ingot. Ingots made of effervescing steel will always contain a large number of blowholes. Such blowholes are not deemed objectionable in certain products if they occur well inside the ingot where they will not be subjcct to oxidation upon cooling, reheating, and rolling or forging of the ingot. Very little top or bottom discard is taken from this type of ingot, as pipes, or large shrinkage cavities, at the upper portion of the ingot do not usually occur, the difference in volume between the liquid and the solid steel (6 to 10 per cent.) being compensated by the innumerable blowholes distributed throughout the body of the ingot. Of the 40,000,000 tons of steel made in the United States during the year 1919, at least 35,000,000 tons of ingots were made of gassy or semi-gassy steel. Killed, or solution, steel is termed true piping steel from the characteristic pipe or shrinkage cavity that usually occurs in the uppermost central portion of the ingot.

Jan 1, 1922

By Richard Henry Lee

Since the economies in the blast furnace resulting from enriching iron ores are so great, much attention has been paid during the past few years to the various methods of concentrating lean ores, and, as the concentrated ore is usually of extreme fineness, various methods of agglomeration and sintering, of more or less value, have been put into operation. The resulting agglomerated concentrates are generally obtained in the form of briquettes or nodules. The briquettes naturally divide themselves into two classes: (1) those made by the mixture of some binding agent, and then formed into briquettes under great pressure; and (2) those made by sintering the concentrates, the latter either being formed into bricks before exposure to heat or the sintered mass broken into fragments afterward. Of the first class I will not speak, as they are not used on an extensive scale in this country. The second class of briquettes, or those made by sintering, are simply masses of melted or fused silicate and oxide of iron mingled with more or less silicates of aluminum, lime, and magnesia. The fact that the material in a briquette is sintered is proof positive that there are no pores in the material. There are, however, quite a number of holes of greater or less diameter through the gubstance of the briquette. They are not pores in the common acceptance of that term as applied to ores by furnacemen, as the ides of the holes and channels are fused. In reality the material is simply mill cinder. It is practically untouched by the gases in the upper part of the furnace, and the iron has to be reduced by solid carbon in the boshes and hearth. Briquettes sometimes show a little saving in fuel in the furnace over an ore mixture of large lumps, but that saving is made simply because, owing to the numerous holes and channels through the mass, the briquette is practically composed of numerous small or fine lumps, and, as is well known, the finer the

Jan 1, 1914

By M. J. Taylor

A common method of classifying non-water- impounding mine waste structures is necessary to facilitate professional comnunications within the industry and between representatives of industry and government. Camnon classifications can a1 so he1 p quickly create and maintain a mental picture of the structures being discussed. Three categories for classification presented in this paper include: (1) configuration and location with respect to existing topography. (2) material characteristics of waste, and (3) environmental sensitivity or characteristic; of the disposal area. Configuration and location classification involve terminologies typically utilized for waste dumps over the past several years. General classification categories for non-impounding structures include: (a) valley-fill, (b) cross-valley, (c) side-hill, (d) ridge, and (e) heaped. Material characteristics can govern the location, engineering details, and environmental sensitivity of the waste structure. Material classification includes: (a) hazardous, (b) non-hazardous, (c) inert, (d) fugitive dust susceptible and (e) leachate susceptible. A1 though many characteristics are potentially applicable, this paper will focus on the categories mentioned above. Environmental sensitivity of a waste structure encompasses many objective and subjective evaluations plus many multi-disciplinary considerations. Environmental sensitivity incorporates numerous factors in addition to those highlighted in configuration and location, and material characteristic classifications. A few examples of how this categorization can govern the engineering design and location of waste dumps are provided in this paper. In addition to the verbal descriptions of classifications, a simplified version of the combined classifications with an alphanumeric format and its methodology is discussed in this paper. Surface water controls often govern the classification or vice versa. In order to maintain a non- impounding status, water must be prevented from collecting behind the structures. Depending on material characteristics, water inflow to or over the site can cause significant environmental or human consequences. Finally, the access of water to the waste dumps can play a large role in the degree of environmental sensitivity to the site. This paper provides a framework in which to discuss the other aspects of this conference and also provides insights as to how the framework is based on actual practice.

Jan 1, 1985

By H. R. Barnhurst

IT would be a difficult matter to trace from the beginning the very few improvements made in the burning of fuels prior to 1860. Doubtless the crossing of the sticks of wood in building a, wood fire early appealed to our savage ancestry as a means of expediting its effectiveness for their crude culinary purposes. Stones and andirons came later in assisting the admission of air to the under part of the fuel bed, while beacons and cressets utilized metal bars as supports for the same purpose. It is probable that Tubal Cain owed his success to the use of bellows making possible the use of mixed fuel and charge upon a hearth. With the development of working in east iron, grate bars cane in, and they are still with us doing duty in every household and almost every art where heat is a factor. Little was done beyond these crude methods prior to 1860. With the advancement of knowledge came the fuel-gas producer, a. natural child of the retorts employed in supplying illuminating gas. It is only within the last 15 years that the conclusion became general that complicated systems for saving heat would not remedy deficiencies in its primary development, and within that tine there has been great advancement in the means of producing initially fire of high efficiency, so that to clay we are moving rapidly toward loth high development and high absorption, with the resultant of high efficiencies. In studying the subject of the availability of pulverized coal as a fuel, it may occur to ask, why has this not come up earlier? This question would be naturally prompted by recalling the fact that Thomas Crompton's English patents upon his methods were issued to Min nearly 40 years ago. A conclusive answer to this, however, is that Crompton at that time had very crude facilities for raking what was at best a, very imperfect pulverization of the coal, and the expense of preparation was very great. He does not seem to have been aware of the advantage of a thorough drying of the coal in the

Jan 10, 1913

By Charles Kirchhoff

For twenty years it has been my work to watch and record progress in both the technical and the commercial branches of mining engineering in the wide sense in which it is represented by our Institute. While you who have been actively engaged in our profession have made history, a few of us have attempted to be the historians and have been kept keenly on the qui vive to follow the developments of so broad a field. One so employed may be pardoned if he ask you to pause for the unusual purpose of looking backward, that you may measure what you and others have done, and that the younger men may gather inspiration from the work accomplished by their elders and their predecessors. It is not so long since that the commercial management dominated our industries. Bred in the school of science, which seeks its reward in establishing the truth, our engineers were sometimes indifferent to trade conditions and requirements. Much of that feeling has disappeared, and the engineer recognizes that it is his mission to apply the achievements of science to a useful commercial end. On the other hand, business men now understand that the utilization of our natural resources and the production of articles for consumption is impossible without the intervention of the engineer. They must co-operate, unless, indeed, the two functions are combined in one man —a rare but powerful combination. Now the final measure of success of both is the cost sheet on the one hand and the expansion of markets on the other, so closely interwoven, so mutually interdependent. There is one cardinal feature, however, which characterizes the engineer's work—namely, the permanence of his achievements. Every improvement, particularly when it has been recorded in such lasting form as a paper in the Transactions of our societies—

Jan 1, 1900

By J. A. Jr. Church

I. EARLY FURNACES. . COPPER blast-furnace construction in America has long recognized a general standard in the rectangular water-jacketed shaft with separate forehearth. The details, however, and especially those relating to shaft dimensions, have had to meet a great variety of conditions, and show no uniformity whatever. Selecting a few of the present day Western plants, we find furnace lengths varying from 12.5 to 87 ft., widths at tuyere level from 42 to 84 in., and heights above tuyeres from 5 ft. 4 in. to 22 ft. 4 in. ; and comparing present designs with those of the past, we meet contrasts no less striking. Unlike its transverse section, the length of a furnace has come to depend rather on the size of unit desired than on the requirements of smelting ; and if the question of length be ignored, several of the various existing designs can be grouped together on the basis of a common transverse section. This section, having a width at tuyere level of 56 in. and a height above tuyeres of 18, ft., was developed at Great Falls, and the story of its development contains some interesting features. Ground was broken for the Great Falls works in the spring of 1891. About a year later, the concentrator was able to begin operation, followed within the next few months by the Brueckner, reverberatory, and converter departments, and in April, 1893, by the first blast fur-

Jan 7, 1913