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By R. M. Leibrock, J. E. Huzarevich, R. G. Hiltz

The various factors considered in recommending the initiation of a gas injection project in the southern portion of the Cedar Lake Field are discussed. Performance history under gas injection operations is reviewed and these data are analyzed, utilizing both the material balance method and the fractional flow and frontal advance expressions. Results of the analysis of the performance data indicate that the injected gas has contacted and affected at least 60 per cent of the reservoir and a substantial increase in ultimate recovery can reasonably be expected. By holding the reservoir pressure appreciably above the bubble point, the well productive capacities have been maintained substantially above the level predicted for primary operations. The analysis of the Cedar Lake project suggests that in certain limestone reservoirs, at least, the probable success of gas injection cannot be predicted simply from ohservation of permeability distribution throughout the pay section, as indicated by core analysis data, on either one or a number of wells. Further, the performance of this particular project fails to indicate any basis for classifying carbonate reservoirs in general as being inherently unsuited to a dispersed type gas injection program, thus indicating that each reservoir should be considered on its own merits, regardless of the composition of the reservoir rock. INTRODUCTION Early in the life of the Cedar Lake Field, an extensive data gathering program was initiated to provide an accurate record of reservoir performance characteristics. From the study of these data it was apparent that there was a critical need for supplementing the natural reservoir energy in order to maintain well productivities and obtain the maximum ultimate oil recovery. Accordingly, detailed engineering studies were made of the various methods of secondary recovery which might be applicable. As a result of these investigations, the decision was made to initiate a gas injection program of sufficient intensity to maintain reservoir pressure at approximately 600 psia, or some 274 lb above the bubble point pressure of 326 psia. A full scale dispersed type gas injection program has been in operation on leases of the Stanolind Oil and Gas Co. in the southern portion of the field for nearly five years, and sufficient performance data are now available to evaluate the benefits which have been derived from this project. It is the primary purpose of this paper to analyze the performance data for the Cedar Lake gas injection project and to point out the significance of the ohserved behavior with respect to certain hypotheses which have been advanced in recent years concerning the probable success of gas injection projects in limestone reservoirs. This paper properly should be regarded more on the order of a progress report, inasmuch as some revision in interpretation will undoubtedly be required from time to time as additional performance data are obtained, although the satisfactory performance of the project to date leaves little doubt as to the ultimate success of gas injection in the Cedar Lake Field. As a result of the success of the project to date, a unit was formed in the southern part of the field, effective March 1, 1951, for the purpose of continuation of the gas injection program. Participants in this unit are the Mid-Continent Petroleum Co. and Stanolind Oil and Gas Co. GEOLOGY AND STRATIGRAPHY The Cedar Lake Field is located in the northern portion of the Midland Basin area as shown in Fig. 1. The southwest portion of the field lies within a playa, or dry salt lake, which covers an area of approximately eight square miles. As might be expected, it was this lake which furnished the inspiration for the name of the field. Except for its value as a salt water disposal pit, this lake has succeeded only in magnifying the difficulties in developing this portion of the field. Typical of this section of West Texas, the area in general is relatively flat and has a semi-arid climate. The localized structure which favored the accumulation of oil is an anticline with approximately 100 ft of closure. The major axis of the structure extends in a general southeast-northwest direction. Originally this structure was defined by seismograph data, which have been subsequently confirmed by development. In general, the geologic column is typical of that found throughout the basin. From the surface to depth of approximately 1,800 ft, surface sands and undifferentiated red beds. probably Triassic. are encountered. Below this point to the producing horizon, all formations are of the Permian age.

Jan 1, 1951

By J. E. Huzarevich, R. M. Leibrock, R. G. Hiltz

The various factors considered in recommending the initiation of a gas injection project in the southern portion of the Cedar Lake Field are discussed. Performance history under gas injection operations is reviewed and these data are analyzed, utilizing both the material balance method and the fractional flow and frontal advance expressions. Results of the analysis of the performance data indicate that the injected gas has contacted and affected at least 60 per cent of the reservoir and a substantial increase in ultimate recovery can reasonably be expected. By holding the reservoir pressure appreciably above the bubble point, the well productive capacities have been maintained substantially above the level predicted for primary operations. The analysis of the Cedar Lake project suggests that in certain limestone reservoirs, at least, the probable success of gas injection cannot be predicted simply from ohservation of permeability distribution throughout the pay section, as indicated by core analysis data, on either one or a number of wells. Further, the performance of this particular project fails to indicate any basis for classifying carbonate reservoirs in general as being inherently unsuited to a dispersed type gas injection program, thus indicating that each reservoir should be considered on its own merits, regardless of the composition of the reservoir rock. INTRODUCTION Early in the life of the Cedar Lake Field, an extensive data gathering program was initiated to provide an accurate record of reservoir performance characteristics. From the study of these data it was apparent that there was a critical need for supplementing the natural reservoir energy in order to maintain well productivities and obtain the maximum ultimate oil recovery. Accordingly, detailed engineering studies were made of the various methods of secondary recovery which might be applicable. As a result of these investigations, the decision was made to initiate a gas injection program of sufficient intensity to maintain reservoir pressure at approximately 600 psia, or some 274 lb above the bubble point pressure of 326 psia. A full scale dispersed type gas injection program has been in operation on leases of the Stanolind Oil and Gas Co. in the southern portion of the field for nearly five years, and sufficient performance data are now available to evaluate the benefits which have been derived from this project. It is the primary purpose of this paper to analyze the performance data for the Cedar Lake gas injection project and to point out the significance of the ohserved behavior with respect to certain hypotheses which have been advanced in recent years concerning the probable success of gas injection projects in limestone reservoirs. This paper properly should be regarded more on the order of a progress report, inasmuch as some revision in interpretation will undoubtedly be required from time to time as additional performance data are obtained, although the satisfactory performance of the project to date leaves little doubt as to the ultimate success of gas injection in the Cedar Lake Field. As a result of the success of the project to date, a unit was formed in the southern part of the field, effective March 1, 1951, for the purpose of continuation of the gas injection program. Participants in this unit are the Mid-Continent Petroleum Co. and Stanolind Oil and Gas Co. GEOLOGY AND STRATIGRAPHY The Cedar Lake Field is located in the northern portion of the Midland Basin area as shown in Fig. 1. The southwest portion of the field lies within a playa, or dry salt lake, which covers an area of approximately eight square miles. As might be expected, it was this lake which furnished the inspiration for the name of the field. Except for its value as a salt water disposal pit, this lake has succeeded only in magnifying the difficulties in developing this portion of the field. Typical of this section of West Texas, the area in general is relatively flat and has a semi-arid climate. The localized structure which favored the accumulation of oil is an anticline with approximately 100 ft of closure. The major axis of the structure extends in a general southeast-northwest direction. Originally this structure was defined by seismograph data, which have been subsequently confirmed by development. In general, the geologic column is typical of that found throughout the basin. From the surface to depth of approximately 1,800 ft, surface sands and undifferentiated red beds. probably Triassic. are encountered. Below this point to the producing horizon, all formations are of the Permian age.

Jan 1, 1951

By G. W. Powell

G. W. Powell (Ohio State University)—Appleton and Bever measured the quantity Es which, for a solid torsion specimen, is basically an average quantity. Es is the amount of energy stored in a solid torsion specimen strained to a surface shear strain of divided by the total number of gram-atoms of alloy in the specimen. It would seem more meaningful and rigorous to deal instead with the quantity which is the energy stored per gram-atom of an alloy uniformly strained to the shear strain . The purpose of this discussion is to demonstrate that as a function of y is readily obtained from the torsion data. radius of the torsion specimen, shear strain at the surface of the torsion specimen density of the alloy, atomic weight of the alloy, and total energy stored in unit length of the torsion specimen. The energy stored in unit length of an elemental tubular section of the torsion specimen is, as given by Appleton and Bever, where E is expressed as calories per gram-atom. The energy stored in unit length of the torsion specimen is

Jan 1, 1963

By William Braden

IT is obvious that the choice of the method to be employed in the handling of blast-furnace slags and mattes depends upon local facilities and conditions which may indicate as advisable some particular plan. As a result of the variety of such conditions hardly any two smelters use identically the same method, though they be located only a few hundred feet apart. For instance, of the several plants in Leadville, Colorado, each has a more or less distinctive system. The same is true of Salt Lake City and vicinity. In view of this it is evident that the existing diversity of practice cannot be accepted, prima facia, as evidence

Jan 1, 1897

By P. W. Bridgman

THE thesis of this article is that the age of Newton is now coming to a close, and that recent scientific discoveries have in store an even greater revolution in our entire outlook than the revolution effected by the discovery of universal gravitation by Newton. The revolution that now confronts us, arises from the recent discovery of new facts, the only interpretation of which is that our conviction that nature is understandable and subject to law arose from the narrowness of our horizons, and that if we sufficiently extend our range we shall find that nature is intrinsically and in its elements neither understandable nor subject to law. The new experimental facts are in the realm of quantum phenomena. Comparatively little has been written for popular consumption about this new realm which has opened in the last fifteen years. The man in the street has been much more interested in relativity, which to him has seemed extremely interesting and revolutionary. Occasionally, however, there has filtered down to him the news that nearly all the theoretical physicists are occupied with a new order of phenomena which they find very much more exciting and revolutionary than any in the realm of relativity. For after all is said and done, the practical effects of relativity, measured in ,dollars and' cents or in centimeters and grams, are exceedingly small, and require specially de- signed experiments executed by men of the highest skill to show their existence at all. The phenomena with which quantum theory deals, on the other hand, are of the greatest practical importance and involve the simplest aspects of everyday life. For example, before the advent of the quantum theory no one could explain why a tea kettle of water boiling on the stove should not give out enough light in virtue of its temperature to be visible in the dark; the accepted theories of optics demanded that it should be visible, but every burned child knew that it was not.

Jan 1, 1929

By W. S. Owen, T. Bell

The variation ox the M, temperature with nitrogen concentration has been determined experinzentally. The free-energy difference between martensite and the parent y Phase at the M, temperature,is computed for Fe-C and Fe-N alloys using recent solubility data fm the Fe-N system and new data for the variatim of the activity of the interstitial solute in the y phase with concentration. The "geometric model" is considered also, and the importance of Zener ordering is noted. It is shown that, although at any chosen concentration the M, temperature and the activity are significantly different in the two alloy systems, the free-energy duference is the same within the limits of experimental error, thus Providing further evidence of the very close similarity between the martensite transformations in Fe-C and Fe-N alloys. TO estimate the free-energy change accompanying the martensite transformation in binary interstitial alloys it is necessary to know the variation of the Ms temperature with interstitial solute concentration and some thermodynamic data. To date, only the Fe-C system has been discussed because this was the only system for which relevant experimental measurements had been made, but even in this case the data available are insufficient to permit the free-energy change to be calculated without the assumption of a thermodynamic model for the y and a solid solutions. The last comprehensive discussion of the topic was by Kaufman, Radcliffe, and Cohen in 1.960.' Since that time Ellis, Davidson, and Bodsworth2 have redeter mined the activity of carbon in y iron as a function of carbon content and Atkinson3 has measured the activity of nitrogen in Fe-N austenite. The M, temperature of Fe-N is reported in the present paper. Thus, it is now possible to assess the free-energy change accompanying the martensite transformation in Fe-N alloys on the same basis as that used to assess the change in Fe-C alloys. This comparison is of interest because it has been shown recently4 that the structure of the martensite formed in Fe-N alloys changes with nitrogen content in a manner exactly parallel to the changes in structure in the Fe-C series and that the strain associated with the distortion of the iron lattice in either the y or the a phase by a nitrogen atom is the same as that produced by a carbon atom. The work to be described tests whether or not this close similarity between the two systems extends to the thermodynamics of the martensitic transformations. THE Ms TEMPERATURES FOR Fe-N MARTENSITE Bose and Hawkes5 found the M, temperature of a eutectoid Fe-N alloy (2.35 wt pct N) to be 35°C. This single determination appears to be the only reported measurement of the M, temperature of an Fe-N alloy. In the present work a series of more than fifteen different specimens containing between 0 and 2.7 wt pct N were prepared by controlled nitriding of pure iron wire 0.010 in. diam. The iron was supplied by B.I.S.R.A. and was designated ACN2. The nitriding procedure, all aspects of which are critical, has been described in detail elsewhere.' Each specimen was quenched from the austenitizing temperature into brine at 20°C without removing the specimen from the ammonia-hydrogen atmosphere in which it was ni-trided. Alloys containing up to 0.7 wt pct N were fully martensitic. More concentrated alloys contained progressively more retained austenite. At 2.34 wt pct N the specimen was completely austenitic after quenching to 20°C. The M, temperature of specimens with M, temperature above 20°C (those containing less than 2.35 wt pct N) was determined by a thermal arrest technique. For the more concentrated alloys (2.35 to 2.70 wt pct N) the variation of electrical resistance with temperature down to -196°C was used. Unlike Fe-C alloys, Fe-N alloys cannot be reaus-tenitized in vacuum or in an inert atmosphere because excessive loss of nitrogen occurs, even in short times, at high temperatures. Consequently, the alloys were reaustenitized in the ammonia-hydrogen mixture corresponding to nitrogen equilibrium at the temperatures used. The specimens were quenched in a blast of cold hydrogen gas and the temperature, measured by a thermocouple welded to the 2.5-in.-long specimen, was recorded on a high-speed recorder. In the first experiments 0.002-in.-diam chromel-alumel wire thermocouples were used but it was found that these gave erroneous readings due to contamination by nitrogen pickup. Pt-Pt 13 pct Rh wires of 0.002 in. diam were found to be satisfactory. Further details of the experiments are available in the original thesis.7 The cooling rate was controlled between 400° and 4000°C per sec by adjusting the hydrogen pressure. At least three cooling curves were obtained for each composition. Each specimen was analyzed for nitrogen after quenching. To aid in the accurate location of the martensite arrest points a series of cooling curves of 0.010-in.-diam platinum wire were recorded and these, which did not contain an arrest, were used as comparison standards. Four specimens, each in the form of a 3-in. loop, were prepared from each of the four alloys containing more than 2.35 wt pct N. One specimen was used for nitrogen analysis, one for X-ray diffraction, and two for resistance measurements below 20°C. The latter specimens were quenched from 20°C into constant-temperature baths at selected lower temperatures.

Jan 1, 1968

By F. P. Nichols, F. A. Renninger

At one time, mineral aggregates were considered physically and chemically inert substances whose junction was that of an inex-pensive, easily obtainable source of bulk. This philosophy applied regardless of the use to which the aggregate was put. Research approaches dealing only with such gross physical properties as hardness, toughness, impact resistance, etc., dominated the early growth years of the industry and influenced specifications to a large extent. The accelerated pace of highway construction, which began toward the end of the depression years, focused attention on the need for extensive aggregate research. The realization in the early 1940's that aggregates interacted chemically as well as physically with their environment provided the stimulus necessary to translate the drab, systematic aggregate technology of the early 20th century into the changing, dynamic, challenging field it is today. Current research problems are discussed in detail. These efforts being pursued by contract research organizations, universities, governmental agencies, and industry transcend many fields. The mineral aggregate industry is the world's largest mining and processing endeavor, yet it is graced with little of the romance or public awareness that accompanies mention of gold, silver, iron, copper, uranium, or aluminum mining efforts. Much of this reaction is undoubtedly due to the fact that the uses to which crushed stone and sand and gravel are normally put are not fully recognized or appreciated by the general public. Almost 2 billion tons of mineral aggregates are quarried or mined, processed, and sold yearly in the United States alone.= The largest uses to which this vast tonnage is subjected are as ingredients of portland-cement concrete, bituminous concrete, and dense-graded aggregate-base course mixtures in the highway and building construction fields, two industries closely related to the expenditure of public funds. It is for these uses, partially in justification for the expenditures of vast sums of public funds, that mineral aggregate research truly finds its emphasis. The research efforts expended relative to the highway and building construction uses to which mineral aggregates are subjected are those of primary concern to the industry. These efforts, while of direct consequence to the industry due to the volume market represented, are of interest as well to public agencies, universities, and contract research firms. All actively conduct research, exchange information, and make contributions to the overall knowledge relative to aggregate usage and limitations. The research efforts of the mineral aggregate industry is the subject to be discussed throughout this paper. It covers all aspects of highway and building design, construction, and technology. The effects of research pertaining to quarrying and mining methods, blasting and processing techniques, storage and handling facilities, and equipment employment and development have left their mark on the crushed stone and sand and gravel industries. Such specialized efforts have resulted in dramatically increased production rates which in turn have served to keep costs, and hence prices, down. Despite the many inflationary pressures over the years, the cost of a ton of aggregate today is little more than it was 25 or 30 years ago. Mention is made of these efforts simply to emphasize the diversity of research in the mineral aggregate field. The remainder of this paper focuses on the complexity of what might be termed "product knowledge" research.

Jan 1, 1971

By Arthur F. Johnson

THE principal costs of making a pound of aluminum are for 9 kw-hr of electricity and for 1.9 Ib of the oxide (A1203) called alumina. A pound of alumina is made by digesting 2 or 3 lb of bauxite in hot caustic solutions, settling and filtering out the oxides of silicon, iron, and titanium and precipitating and calcining the A1203 as a pure, white powder. The cost of foreign bauxite delivered at an alumina plant in the U.S. may equal or exceed the cost of its chemical treatment to make alumina. Some of the principal factors affecting costs in the utilization of foreign bauxites are: transportation from mine to market, mineralogical and physical composition of the bauxite, thickness of the bauxite beds and their clay and forest overburden, amen- ability of the bauxite to beneficiation and to caustic extraction of the alumina, and lastly size of bauxite deposits and rate of mining employed.

Jan 6, 1954

By Richard D. Hagni

Although the ore microscopist routinely examines polished sections to determine the mineralogy and texture of ores, his importance to the solution of problems peripheral to geology is not always fully realized. The techniques which he uses can be applied with little modification to the solution of a wide variety of beneficiation problem. By extending his studies beyond those normally considered to be of interest to the geologist, he can include examinations of polished sections of selected mill products. This is a logical extension, because the minerals and textures in the polished sections of ores are the same as those in millproducts. The mill dressing engineer should be more aware of the types of beneficiation problem that can be solved by the ore microscopist and what the ore microscopist can do for him. A greater degree of cooperation between the ore microscopist and the mill dressing engineer can be of significant mutual benefit. Ore microscopy holds an advantage over chemical analysis, because the interrelations and combinations ofthe mineral constituents of an ore or mill product can be visually determined. This advantage provides solutions to many beneficiation problem. Locking is a type of beneficiation problem that is particularly amenable to ore microscopy. The percentage, type, and distribution of locked particles can be readily determined with the aid of an ore microscope and an estimate made of the extent of additional grinding required for liberation. The extent of intimately locked types, which no reasonable amount of grinding will liberate, can also be evaluated. Mineral coating conditions, free particles of a deleterious mineral, and free particles of a valuable mineral held in flocculated clusters of gangue are other features that can readily be observed. In some instances, visual examination may show that the problem is not one of locking. Photomicrographs illustrate the variety of beneficiation problems for which the ore microscope is applicable. These problems and their resolution demonstrate the importance of the instrument and show the value of close coordination between the mill dressing engineer and the ore microscopist.

Jan 1, 1979

By W. A. Wood, W. H. Reimann, Maria Ronay

The basic mechanism of fatigue is studied in annealed a brass subjectecl to alternating torsion at room temperature, 100°, 200°, 300°, and 400°C, and in air. It is shown that the slip-zone micro-cracking which characterizes fatigue damage produced by small amplitudes at room temperature is progressively replaced by grain boundary cracking at elevated temperatures, replacement being complete at 400°C. Replacement occurs not because slip activity decreases hut because slip movements at elevated temperatures cease to concentrate in narrow zones and instead disperse. Decrease of amplitude at 400°C through permitting longer lives of specimens before fracture actually causes in- MOST studies of fatigue at elevated temperature have been concerned with data for design. Observations on the basic mechanism of fatigue have been largely incidental, though they have led to the interesting inference that this mechanism has features in common with that of creep.' This paper is concerned primarily with the mechanism itself. Advantage has been taken of mater- crease in pain boundary damage, an anomaly attributed to the greater difficulty at elevated tempwature of starting and propagating a crack. Surface corrosion was most pronounced along slip bands but since at elevated temperatures the slip hands showed no cracking the surface corrosion did not appear to influence onset and early spread of fatigue damage. Similarly the type of fatigue damage produced at room temperature by cyclic strain at large amplitudes, characterized by irregular mi-crocracks at zones between disoriented regions in a grain, was also replaced by mainly grain boundary cracking at elevated temperature, though not so completely. ials and procedures known to show readily how fatigue affects the microstructure of a metal at room temperature, so that direct comparison might be made with what the same procedures show when the material is subjected to fatigue deformation at higher temperatures. 1) MATERIAL This was 70/30 a brass, used extensively in previous studies at room temperature.' Specimens were turned from extruded rod to have parallel test portions 1-1/4 in. long and 7/32 in. diameter, annealed to a grain size -1/10 mm, and electro-

Jan 1, 1965

By George H. Willis

In the second half of the 19th century, bimetallism progressively was replaced by gold standard. After World War I and the 1931-33 depression, gold was mainly reserved for official international transactions and internal use was restricted. Changes since 1971 have shrunk official international use of gold. International payments deficits and surpluses are now financed by Private and official credit, rarely by gold. This historical review covers evolution of: (1) internal and external private use, (2) internal official use, (3) external official use, (4) its role in the International Monetary Fund, and (5) use as unit of account. For this paper I have tried to take a longer perspective than is usually possible, and to look, even if very briefly, at the changing relationship of gold to the monetary system over the last 200 years or so. There are, I believe, some long-term trends, continuing down to the present day. These trends have seen gold replaced by some form of paper assets in one monetary function after another. These past trends may help us to understand where gold stands now, and possibly will throw some light on the future. Because it seems to me that gold in the past has performed various functions related closely or marginally to money, I have divided this rapid historical review into several sections: (1) the internal and external private use of gold, (2) the internal official use of gold, (3) the external official use of gold, (4) gold and the International Monetary Fund, and (5)gold as a unit of account.

Jan 1, 1980

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members) Graduate mining and metallurgical engineer now open for engagement. Member, 38 years old, married, 19 years' experience in United States, Europe, South America, Africa, in exploration work, surveying, assaying, mining, milling, ore-dressing, construction and management. Four languages mastered. No. 355. Member, aged 35, technical graduate, desires position -as superintendent or assistant superintendent of spelter or zinc oxide furnaces, or both. Gas producer experience, zinc metallurgical and laboratory experience. Can handle men. No. 356. Member, also Assoc. Mem. Am. Soc. of C. E.; excellent technical education, and best of references covering twelve years in responsible charge of work; experienced in surveys, construction, prospecting, mine examination and development and irrigation work; speak Spanish fluently, and can write a good report. Good executive. Available during June. Age 34; married. No. 357.

Jan 6, 1917

By G. F. Comstock

H. M. BOYLSTON, Cambridge, Mass.-It might be asked, since this test is so simple, why it was not discovered before. It seems to me the explanation is that when we have used the sodium picrate solution, it has .generally been on a very, high-carbon or hypereutectoid steel; to detect . the presence of free cementite, and when we have looked for sulphides, it

Jan 4, 1917

By Benjamin C. Greene, H. Beecher Charmbury

Water is a most remarkable substance, essential for life of all kinds. As well as needing water to survive, man has always used it for agriculture, transportation, recreation, and many other things. When our country was young and inhabited by few people, the streams, rivers, and lakes were able to provide all the clean water needed by man and take away all the wastes created. However, with our growing population and an ever-increasing demand for goods and services, the public, industry, and government at all levels have become acutely aware of the need to manage the nation's water resources more efficiently. Abundant energy from many sources has helped this nation to become the greatest industrial nation in the world. Coal has contributed a major portion of this energy, generating electricity, running railroads, and maintaining national security during wartime. The result has been the highest standard of living in the world and a time of widespread economic prosperity. The use of water in coal mining is somewhat different from its use in most industries. With the exception of water used in cleaning plants, for underground dust control, and for fire protection, most of the water en- countered in coal mining operations serves no useful purpose. In other words, it is an undesirable element and must be removed, otherwise it will interfere with operations, cause potential water quality problems, and may even stop operations by flooding. In the past, removing water from working areas of most mines was usually a fairly simple matter. Pumps with piping were installed at sumps or low spots in the mine and the water was pumped to the surface or to drainage control facilities constructed for the operation. Ditches were often used to collect and drain the water by gravity to the outside or to main sumps for pump discharge. In either case, the water was allowed to flow into the nearest stream or river. The concept of "water is water" was generally accepted without too much concern for what was in

Jan 1, 1981

R. F. McELVENNY.- The next item is: "Center and other methods, vs. side charging." That was all discussed in the Carson case, and I do not know but what many of the plants are still using center charging. Some are using side charging. Did I understand that where you use the wet charge it is all side charging on the wet ore? B.-G. C. HONEYMAN.- We were on center charging for about a year with wet ore. R. F. McELVENNY.- Then you went to side charging. Has anyone any remarks to make on side versus center charging? E. A. BARNARD.- We have one side and one center, both on deep bath. It is an experimental proposition so far, but the side charge looks very favorable.. R. F. McELVENNY.- This is with calcine? E. A. BARNARD.- This is with calcine on a floating charge proposition.. They are both water jacket. The charge acts very similar on both center and side charging. The calcine spreads much the same as it does on the center charge. It will run down 75 ft. on the furnace side as well as the center. The advantage is in taking care of secondaries and things of that nature. C. BARDWELL.- Do you get any side wall protection from it? E. A. BARNARD.- No. R. F. McKENZIE.- Do you not project the side wall up to protect the skewback? E. A. BARNARD.- There is a slot projection down around the top of the bath; but the repairs on the side wall have been practically the same; that is, they, have been practically the same as they have on the center charge. A. H. RICHARDS.- A point I would like to make is that if you have any doubt about the center charging, we feel that we get better tonnages and lower fuel ratios and better slags with center charging than we ever got with side. Different kinds of charges would, of course, vary, and I could readily see that if you had the same advantage with deep bath smelting that you mention you would probably get just as good a slag and as good fuel ratios. E. A. BARNARD.- In fact, I think the calcine charge spreads more on the side than on the center charge. A. H. RICHARDS.- If you maintain a deep bath. E. A. BARNARD.- That is one thing we have to be careful about, to hold the charge back.

Jan 1, 1930

By Alexander Gakner

Since the end of World War II the Soviet Union has made great strides toward economic development of the country. Today it is firmly established as the world's second largest industrial power after the United States and it has committed itself before the people on both sides of the Iron Curtain to catch up with and to overtake us within a few decades. No nation could achieve such a degree of industrialization or aspire to become the world's industrial leader without a large supply of many basic mineral raw materials or at least easy access to such resources. In addition, it requires technical competence, a large skilled labor force, and a high rate of capital investment. Why should we concern ourselves with these Soviet aspirations? The Free World's yardstick of measuring a nation's well-being is the standard of living of the people in that country. Presumably even Communist governments are committed to some, however gradual, improvement in the standard of living of their people. The population of the USSR is 20 pct greater than that of the United States. Hence, if they ever achieve a standard of living equal to ours, they must by all logic reach a greater overall industrial output. However, in the U.S.S.R. the standard of living of the masses has not kept pace with the expanding industrial production and is still far behind that of the United States. Our concern, therefore, is with what the USSR intends to accomplish with its expanding industrial power: Will they produce large mineral raw-material surpluses and manufacture products to compete with us for world markets and attempt to put us out of business if not use it directly to wage war; or will they use their resources merely to produce more consumer goods for the Soviet people; or will they, along with other Communist nations in the not-too-distant future, compete with us for the world's sources of mineral raw-materials to maintain a high level of mass consumption?

Jan 6, 1960

By E. J. Roberts

Prior to 1916, thickening was an art, and any accurate decision as to what size of machine to install to handle a given tonnage of a specific ore must have been one of those intuitive conclusions, based on both intimate and extensive acquaintance with thick-ners and ore pulps. Then in 1916 "knowledge of acquaintance," became "knowledge about" with the publication of the Coe and Clevenger paper.' The unit operation of thickening had graduated to the status of an engineering science. The fundamental similitude relationships for the two major phases of the operation were defined so clearly that batch tests on models as small as liter cylinders could serve to specify protypes as large as 325 ft in diameter. It is quite apparent from reading the literature that Coe and Clevenger's contribution is not generally appreciated. In so far as the basic engineering relationships are concerned, the only real advance which has occurred in the 30 odd years which have elapsed since the Coe and Clevenger paper is the recognition of the effect of the rakes on the thickening process. Bull and Darby2 noted this in 1926, and the extensive use of the "gluten type" thickener, in which the effect is magni-fied, bears witness to its importance. Comings3 further verified this effect of the rakes. As a matter of fact, a number of papers show an apparent regression from the Coe paper in that the area determinations are made on the basis of a single test from One concentration of solids. Coe and Clevenger amply demonstrated that this is unsafe, since the controlling zone may be one other than that of the feed dilution. Comings3 neatly demonstrated this without apparently realizing it. Of course there have been significant advances in the application of the operation to industry. Open tray thickeners were introduced to save area; balanced tray thickeners, washing thickeners, and multifeed clarifiers were developed with all of their special hydraulic and mechanical problems. Combinations of all kinds have been introduced, such as combination agitators and thickeners, combination flocculators and clarifiers, combination thickeners and filters. With the establishment of the operation on a firm engineering foundation, installation was facilitated and expansion proceeded. There are still problems, of course, functional as well as mechanical. Sometimes the moisture in the underflow obtained in practice is not as low as is expected on the basis of the test data. Sometimes the underflow is so "thick " that its discharge and subsequent handling requires special attention. Island formation plagues some operators. The use of the thickener as a surge basin and blending tank in the cement industry poses unusual problems. Design of rakes and the drive mechanism must be continually im-proved. Corrosion problems must he overcome. Power requirements for raking the settled solids occasionally is the controlling factor as it was in the case of the all American Canal desilting installation. Other similitude relationships and design problems come into the picture when we enter the field of clarification or nonline settlement. We have an energy dissipation problem in introducing the feed and any models must satisfy the Froude model relationships. Autoflocculation requires detention which involves the same similitude laws that we encounter in the compression zone. Approach to an Exact Science The next step beyond having control of the similitude relationships is to understand the why of these relationships right back up the line to first principles. The ultimate might be that, if given the mineralogical composition of the solids and their size distribution together with an analysis of the suspending liquid, we could calculate the entire thickening behavior of the system. Then we could say we had reduced the operation to an exact science. True it might be more trouble getting this basic analytical data than to make our empirical determinations for area and volume, and we would need an ENIAC to calculate the results, but that does not detract from the desirability of such understanding. Considerable work has been done by the chemical engineers with this end in view. Comings,3 Egolf,4 Work,5 Kam-mermeyer,6 Steinour,7 and others have studied the problem. The writer has no final answer to the thickening story but would like to propose a picture of the mechanics of the two phases of thickening which has been found useful in understanding the subject and which leads to some convenient relationship in treating the compression step and arriving at the compression depth.

Jan 1, 1950

The Institute published a collective index of- Volumes I to XXXV inclusive, which has been very extensively purchased and used by the members of the Institute. It enables one to look, up any subject in the first thirty-five volumes and is useful to those who have the Transactions, as well as to those who have not, because it tells what subjects have been treated and enables one to look these matters up in his own library and then afterward either to procure the individual papers from the Institute at the price of $1 each, or to procure Volumes, or to consult the Trans-actions at a nearby library, if such a one is available. It now seems desirable to publish another collective index, and the Editorial Department, upon the authority of the Board of Directors, has prepared an index of Volumes XXXVI to LV inclusive. This will be sold in the Institute's standard half morocco binding at a price of $5 and in paper covers at a price of $4. It wilt be ready in a few weeks. Those who already have the first index and purchase the second one, and those who purchase both, will have a complete index of the Transactions from Volumes I to LV inclusive. The Institute will be glad to receive advance orders for this index to insure prompt delivery upon publication.

Jan 8, 1917

By M. J. Williams, C. P. Proctor, J. T. Crawford

The purpose of this paper is to present some data and comparisons regarding three types of Rheolaveur plants washing bituminous coal from the Pittsburgh seam. It deals only with the sections that handle coarse coal. The Rheolaveur system consists of launders or troughs in which coal and its associated impurities are conveyed by water. The impurities. being heavier than the coal, settle toward the bottoms of the launders and are drawn off through specially designed openings called Rheo boxes. Fundamentally, each plant consists of straight-sided, flat-bottomed launders of varying width and length, each launder equipped with one or more Rheo boxes for the removal of high-grauity fractions of the feed that are undesirable in the cleaned coal. Each launder has at least two longitudinal sections, the first with a slope of from 11/2 to 4 in. per foot of length, called the classification section. The single-box launder has a classification section followed by a washing section ahead of the box. A two-box launder is a single-box launder followed by a washing section and a second box. The slope of the washing section between the first and second boxes is determined to some extent by tonnage. At the end of the classification section, which may. vary from 8 to 15 ft. in length, the slope abruptly flattens out to a slope of from 92' to 1 in. per foot of length. This flatter section of the launder, called the washing section, may vary from a few feet, in a single-box launder, to 15 ft., in a two-box launder. Raw coal entering the head end of what we choose to call the "primary" launder or launders is pushed down the classification section by a stream of water entering the head end of the launder with the coal. As it strikes the washing section, of lower pitch, the velocity of flow is retarded and the heavier particles of slate, pyrite, bone, etc., take their places on the bottom and are drawn off as they pass over the Rheo boxes. The clean coal, of lighter gravity, remains on the top of the stream of

Jan 1, 1938

By M. J. Williams, C. P. Proctor, J. T. Crawford

The purpose of this paper is to present some data and comparisons regarding three types of Rheolaveur plants washing bituminous coal from the Pittsburgh seam. It deals only with the sections that handle coarse coal. The Rheolaveur system consists of launders or troughs in which coal and its associated impurities are conveyed by water. The impurities. being heavier than the coal, settle toward the bottoms of the launders and are drawn off through specially designed openings called Rheo boxes. Fundamentally, each plant consists of straight-sided, flat-bottomed launders of varying width and length, each launder equipped with one or more Rheo boxes for the removal of high-grauity fractions of the feed that are undesirable in the cleaned coal. Each launder has at least two longitudinal sections, the first with a slope of from 11/2 to 4 in. per foot of length, called the classification section. The single-box launder has a classification section followed by a washing section ahead of the box. A two-box launder is a single-box launder followed by a washing section and a second box. The slope of the washing section between the first and second boxes is determined to some extent by tonnage. At the end of the classification section, which may. vary from 8 to 15 ft. in length, the slope abruptly flattens out to a slope of from 92' to 1 in. per foot of length. This flatter section of the launder, called the washing section, may vary from a few feet, in a single-box launder, to 15 ft., in a two-box launder. Raw coal entering the head end of what we choose to call the "primary" launder or launders is pushed down the classification section by a stream of water entering the head end of the launder with the coal. As it strikes the washing section, of lower pitch, the velocity of flow is retarded and the heavier particles of slate, pyrite, bone, etc., take their places on the bottom and are drawn off as they pass over the Rheo boxes. The clean coal, of lighter gravity, remains on the top of the stream of

Jan 1, 1938