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By L. A. Geoffrion, R. H. Perkins, J. C. Biery

Densities of cerium metal and several lour-melting binary cerium alloys were measured over the range 25° to 800°C. A rolumeter, using NaK as working fluid, was used to obtain the data. The cerium, Ce-Co, Ce-Ni, and Ce-Cu alloys all exhibited an increase in density on melting, while a Ce-Mn alloy expanded on melting. FOR the proper design of a nuclear reactor, the change in density of the fuel with temperature must be known. This is especially important in a system utilizing molten fuel, such as LAMPRE (Los Alamos Molten Plutonium Reactor Experiment), since a relatively large change in density usually occurs during the solid-liquid transition. The fuel for LAMPRE is a Pu-2.5 wt pct Fe alloy with a melting temperature of 410°C. However, limitations in reactor design with this fuel have led to consideration of other plutonium-containing alloys for use in future generations of this type of reactor. Several ternary alloys containing plutonium and cerium as two components have satisfactorily low melting points. The system that at the present time appears to be most acceptable is Pu-Ce-Co; it exhibits little change in melting temperature with wide variation in plutonium concentration. Other alloys that have received some consideration contain nickel, copper, and manganese as the third constituent. The proposed fuel alloys are difficult to handle experimentally in the 25" to 800°C temperature range since they oxidize readily, react with many solvents, and contain a poisonous fissionable material. In addition, in this temperature range the alloys pass through the solid-liquid transition. Several techniques are available for measuring the densities and volume coefficients of expansion of solids or liquids. However, the only apparatus that appears suitable for measuring expansion coefficients over this temperature range and through the phase transition is a volumeter. In a volumeter, the indicating medium must be essentially inert to and insoluble in the material being studied. It must also possess a low vapor pressure over the operating temperature range, and its coefficient of expansion must be accurately known. One material that is satisfactory in nearly all of these respects is the alloy Na-78 wt pct K, which melts at -10°C and has a vapor pressure of 860 mm Hg at 800°C. This relatively high vapor pressure at 800°C requires an overpressure of an inert gas to prevent boiling. While a volumeter is capable of determining accurately the volume coefficients of expansion of materials, it cannot be used for absolute density measurements. Therefore, a density determination at a known temperature must be coupled with the volumeter measurements to give all the desired data. The weight-loss technique using immersion in bromobenzene at room temperature proved to be satisfactory. The preliminary work that was done on this experimental program involved developing and calibrating the equipment, and measuring the densities and volume coefficients of expansion of cerium and some low-melting binary cerium alloys. The complications that are caused with the introduction of plutonium into the system were avoided until the equipment was proved to be satisfactory and until experience was gained in its operation. It is this first phase of the experimental work that is described in this report. DESCRIPTION OF EQUIPMENT AND OPERATING PROCEDURE The NaK volumeter is shown schematically in Fig. 1. Basically, the equipment consists of two weld-sealed stainless-steel containers of nearly identical volume. One container holds a tantalum crucible and the specimen being measured; the other contains a tantalum crucible and a tantalum specimen used as a control reference material. To avoid temperature gradients, the bombs are located in a copper block inside the furnace. Stainless-steel capillaries of equal length and volume connect each stainless-steel container to a glass viewing capillary. The stainless-steel containers, stainless-steel capillaries, and a portion of the glass capillaries are filled with NaK (22 wt pct Na-78 wt pct K). The NaK/gas interface in the glass capillary is viewed with a cathetometer which is accurate to *0.5 mm. The cathetometer readings are used to calculate the volume changes of the samples during a run. This volumeter is basically the same as that described by F. Knight in Plutonium 1960. 2 However, changes in equipment design and operating procedure were made to eliminate some major operating difficulties. These changes are summarized below. 1) In filling the manometer with NaK, gas was frequently entrained in the system. Evacuation of the system before filling failed to eliminate the en-

Jan 1, 1965

By C. L. Mantell

Although so common and well known a metal, tin is really a less abundant element than many of those less familiar and usually ranked with the scarce or rare elements, such as cerium, yttrium, lithium, beryllium, titanium, zirconium and vanadium. The color of tin is white, with a slightly bluish tinge. When it is compared with nickel, the latter metal is brown. When placed alongside of tin, chromium is definitely blue. Tin is whiter than silver or zinc. Exceedingly thin films of tin show various shades of brown by transmitted light. The metal has a brilliant luster, and when mirror-polished, has high light reflectivity. The luster depends to a large extent upon the pouring temperature at which the metal is cast. If the temperature be too high, iridescent colors may show on the surface. These are the result of oxide film formation. If the pouring temperature be too low, the surface is dull. Small amounts of foreign metals, such as lead, arsenic, antimony and iron, decrease the luster of tin and impart a yellowish tinge to the metal. The structure is decidedly crystalline. The cast metal is a mass of crystals. When a bar of tin is bent, it emits a characteristic creaking sound. This is called the "cry" of tin, resulting from the grinding of the crystals one against the other during the bending of the metal. Tin metal may lose its crystalline structure by cold working, but grain growth occurs rapidly under the influence of heat. Metal which has been cast at a low temperature may become amorphous as the result of mechanical work. If such material be heated to temperatures well below the melting point, say at 110° C. for a half hour or for a few minutes at 150" C. recrystallization occurs. If the surface of tinned plate, tin foil, or tin meta1 in cast form be etched with hydrochloric acid containing a little free chlorine, attack occurs at the intererystalline faces. The surface shows patterns resembling the frost flowers on window panes in winter. The etched appearance is called moire metallique. Fine dendritic surface crystals of tin may be obtained by casting the metal on a surface of polished steel. In commercial tin plate, the intercrystalline boundaries are shown by fine grooves or channels, .which result from the method

Jan 1, 1929

By C. L. Mantell

Although so common and well known a metal, tin is really a less abundant element than many of those less familiar and usually ranked with the scarce or rare elements, such as cerium, yttrium, lithium, beryllium, titanium, zirconium and vanadium. The color of tin is white, with a slightly bluish tinge. When it is compared with nickel, the latter metal is brown. When placed alongside of tin, chromium is definitely blue. Tin is whiter than silver or zinc. Exceedingly thin films of tin show various shades of brown by transmitted light. The metal has a brilliant luster, and when mirror-polished, has high light reflectivity. The luster depends to a large extent upon the pouring temperature at which the metal is cast. If the temperature be too high, iridescent colors may show on the surface. These are the result of oxide film formation. If the pouring temperature be too low, the surface is dull. Small amounts of foreign metals, such as lead, arsenic, antimony and iron, decrease the luster of tin and impart a yellowish tinge to the metal. The structure is decidedly crystalline. The cast metal is a mass of crystals. When a bar of tin is bent, it emits a characteristic creaking sound. This is called the "cry" of tin, resulting from the grinding of the crystals one against the other during the bending of the metal. Tin metal may lose its crystalline structure by cold working, but grain growth occurs rapidly under the influence of heat. Metal which has been cast at a low temperature may become amorphous as the result of mechanical work. If such material be heated to temperatures well below the melting point, say at 110° C. for a half hour or for a few minutes at 150" C. recrystallization occurs. If the surface of tinned plate, tin foil, or tin meta1 in cast form be etched with hydrochloric acid containing a little free chlorine, attack occurs at the intererystalline faces. The surface shows patterns resembling the frost flowers on window panes in winter. The etched appearance is called moire metallique. Fine dendritic surface crystals of tin may be obtained by casting the metal on a surface of polished steel. In commercial tin plate, the intercrystalline boundaries are shown by fine grooves or channels, .which result from the method

Jan 1, 1929

By Norman Weiss

IF we were to measure progress this year in terms of large new mills and discoveries of fundamental significance we should certainly be disappointed. Outside of the uranium field there was little of a spectacular nature. San Manuel and Reserve completed their first year of operation; Erie approached readiness; the Toquepala project in southern Peru broke ground and gained speed. Important mill enlargements occurred at Inspiration, Anaconda, Ray, and Climax Molybdenum. A 3000-ton copper concentrator was completed at Pima, near Tucson. The Republic Mill of Marquette Iron Mining Co. started up in April. Abroad, the great developments in the African Copper Belt can be likened to the rapid growth of the porphyry coppers in this country. Fundamental research was confined nearly entirely to iron ore flotation and recovery of metal values from leach solutions, particularly uranium. The large number of review articles this year reflected a desire to take stock and consolidate past gains before taking the next bold steps. Undoubtedly a shortage of competent young engineers and technicians is stunting the natural growth of theoretical investigation in the field of minerals beneficiation, as well as the conversion of ideas into action. We find our small stock of talented young scientists concentrated in a few centers of erudition because there are not enough to diffuse through the industry. It is safe to say that among mine administrators and managers there is more interest in the education, training, and welfare of the young engineer than ever before.

Jan 2, 1957

A-Metal Mining B-Minerals Beneficiation F-Coal H-Industrial Minerals

Jan 11, 1950

By A. B. Kinzel

INCLUSIONS of nonmetallic matter have long been recognized as objectionable in steel. A complete theory of the effect of inclusions, which is consistent with that held today, was outlined in Howe's early work on the metallurgy of iron and steel. This, by analogy with wrought iron, assumes that the observed difference in properties between specimens with and across the direction of rolling is due to slag enclosures. The fact that wrought iron shatters in ballistic test is taken as an indica-tion of the effect of inclusions on the resistance to shock. Since that time, the development of the metallurgical microscope has shown the discrete nonmetallic inclusions in the iron matrix. Better resolution has, brought out the great number of inclusions, and the availability of good microscopes in steel mills and laboratories has constantly drawn more attention to these inclusions. This recent emphasis on inclusions has resulted in studies as to their nature, mode of formation and methods of elimination, such as the work of Wohrman, Dickenson, Herty, and Schenk. In addition to the published works; many investigations which have not been published' have been carried out by private laboratories and have resulted in the application of specifications intended to limit inclusions in many qualities of steel. Nevertheless, a clear understanding of the quantitative effect of inclusions on the physical properties of steel has been lacking. It is the specific purpose of this study to determine the quantitative effect of inclusions on the physical properties of steel that determine its behavior under dynamic stress. The study has shown that a quantitative relation between counted inclusions and impact strength does exist in normalized steels, but 'that factors other than readily visible inclusions are equally important. Furthermore, the present commercial rating of inclusions is unreliable with respect to counted inclusions or dynamic tests, and this study indicates that the tensile-impact test is more reliable as a measure of quality.

Jan 1, 1931

By C. D. Thompson, D. C. Violetta, C. A. Czako

The mechanics of the continuous sintering process are briefly reviewed and the application of this process for the beneficiation of principal minerals used in making cement is shown. Pilot plant tests using pyrobeneficiation techniques were conducted with mixtures of limestone and shale in various ratios. Results are illustrated and show the percentage removal of carbon, carbonates, sulfur, alkalies, and volatiles as a function of the limestone-shale ratio. Tests with varying quantities of solid fwls, added to mixtures containing limestone and shale in a 4 to 1 ratio, were made to attain optimum elimination of the volatile constituents. Experimental results show that 90 pct of these constituents were removed during the calcination sintem'ng process. The advantages of using the beneficiated material for making cement are discussed with regard to prepam'ng, handling, and clinkering operations. A sintering process for treating raw materials or kiln waste products which contain high amounts of alkaline materials is described. Tests were performed with a high alkaline waste dust mixed in a 1 to 1 ratio with raw cement meal. The data from these tests and others using different halides for aiding alkali removal are evaluated by the alkali content of the cement clinker. Test results showed that the Dwight-Lloyd process could be applied with facility in beneficiating raw materials for cement making. Substantial quantities of deleterious volutile constituents were removed by calcining and sintering techniques. The continuous sintering process has been applied for a number of years as a means of beneficiating minerals for subsequent conversion to merchantable products. The process was developed and first used for nonferrous metallurgical applicatfons. However, it has risen to prominence for ferrous metallurgical applications where last year in the U.S. and Canada nearly 40 million tons of iron ore were treated by grate firing processes. Through the years of process development many investigators have realized the versatility of the sintering process and have directed experiments toward the use of it for applications with nonmetallic minerals. These have included calcining limestone, carbonizing coal, expanding shale, and burning cement raw meal. Today commercial sintering plants produce cement clinker from mixtures of limestone and shale, lightweight aggregate from shale or clay, and calcined products from phosphate shale. The mechanics of the downdraft sintering process have been presented by many authors. In general practice the materials to be agglomated are mixed as moistened fines with a solid fuel and this mixture is spread uniformly on the grates of the sintering machine. The charge is then momentarily directed under an ignition furnace. After ignition a continuous downdraft of air promotes combustion of the fuel and through heat transfer particles become partially fused into a coherent mass. This is cooled from continued draft induced after combustion. Many investigators have shown that distinct zones are formed during the process of sintering iron ores. At the midway point of the sintering process these are prominent and are, respectively, from the top of the bed to the bottom, comprised of a cooling zone of sintered material, a combustion zone of sinter formation, a calcination zone, a drying zone, and a zone of unreacted materials. Completion of sintering occurs near the discharge end of the machine where the firing zone approaches either the grates or grate dressing material called hearth layer. Here the peak draft temperature usually can be noted in the windboxes. The zonal pattern has been illustrated with the use of graphs which show thermal gradients as they progress through the bed of materials during sintering. Fig. 1 shows, in simplified form, thermal gradients existing when clinkering cement on a sintering machine. The thermal gradients illustrated are for periods of initiation, midway and completion of the clinkering process. The occurrence of these zones has importance for the beneficiation of cement raw materials. A research program was performed at the Dwight-

Jan 1, 1961

By Bain, Edgar C.

THE results are presented of an investigation to discover the fundamental atomic conditions existing in Corson's high-copper alloys hardenable by means of silicide solution and reprecipitation. The study attracted the writer because it offered a very convenient example of the general type of hardenable alloys exemplified by duralumin. Sykes' iron-tungsten and iron-molybdenum alloys and the hardenable lead-antimony. SUMMARY OF RESULTS AND CONCLUSIONS In brief, the investigation shows that very perfect crystallinity exists in the solid solutions prepared at high temperature to contain as much dissolved silicide as possible. The lattice parameter of copper is altered very little by the amount of cobalt, nickel or chromium, and silicon dissolved. The hardening by drawing at a temperature to initiate precipitation of excess silicon and metal produces a remarkable change in the atomistics of the solid solution. The old perfection of crystallinity in the solid solution is destroyed and the new atomic spacings are of variable magnitude even in one grain, and a condition in a measure resembling that found in martensite is observed. Were no particles whatever precipitated by the drawing action, still ample causes for hardness would be in evidence in the solid solution alone. The lack of plane continuity in the crystal grains would oppose slip in a very effective manner. Complete annealing restores the crystalline perfection in large measure. In these alloys even the most sensitive methods failed to reveal the characteristic pattern of the silicide precipitated by the anneal, but this was largely to be expected as the amount is relatively small.

Jan 1, 1927

By Robert W. Fullerton, Barry G. McMillan, Donald T. King, Henning E. Soderberg

INTRODUCTION Dust control in coal preparation and related transport is a multi- faceted problem which must be anticipated whenever dry, fine coal is subject to rough handling which can disperse it in the air. This problem can be minimized by careful planning and proper design, by eliminating procedures which maximize dust production, and by utilizing the most appropriate dust-collection "hardware" for a given situation. Proper maintenance after dust-collection systems are installed is also very important, and will not only enable the selected equipment to perform properly, but will also reduce component wear, recover valuable product with the highest efficiency, provide cleaner and safer working conditions, and allow local clean-air standards to be met. This chapter is designed to provide basic information about dust control in relation to material processing and handling during coal preparation. Areas discussed should provide the reader with insight into basic dust-collection theory, particle behavior, equipment types, ductwork and hood considerations, general maintenance and design planning, and the economics of dust collection. Because of the wide range of areas covered and the various specialized problems inherent in each, the text is organized to be a practical reference, and not a complete, unabridged treatise of ventilation and dust-control design. Nevertheless, the information presented should be of value in both understanding and reducing problems of dust control in coal preparation.

Jan 1, 1979

By George Bain

SOME problems concomitant with commercial exploitation of marble are presented as examples of interesting, useful and profitable fields for application of scientific knowledge. The marble industry is only one such field and is selected because its varying new aspects are familiar to the author. However, what is true for marble is equally so in principle for many industrial minerals. The problems of any stone industry are to maintain markets, create new outlets for stone already in demand, and develop varied uses for varieties that are not so popular. Here the geologist has a different role from most of his colleagues in metal mining. The producing branch may ask about the expectable variation in thickness or size of a deposit as development proceeds. The stock department may call for the available amount of a given type of stone before accepting a large order. The sales force requires data on the use for stone from certain parts of deposits in order to divert grades to the most suitable use. The service depart-ment wants defects rectified and the cause determined to avoid recurrence. The mills want data on durability and cutting quality of abrasives. The geologist occupies no special department; he is on general call, as may be illustrated by a few types of problems that may be classified as: (1) dominantly geological in character, (2) dominantly chemical in character, (3) dominantly physical in character.

Jan 1, 1940

By Walter Herd

Fox the past eight years No. 2 mine of the Cumberland Railway & Coal Co., Springhill, Nova Scotia-a subsidiary of the Dominion Coal Co., Ltd.-has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent that some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Department of Nova Scotia requested from the U. S. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of -Public Works and Mines, Nova Scotia. Prior to 1925, the room and pillar method was employed and in January of that year (there being a cessation of work from March to August due to labor troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence, had not been experienced. In the interval development work for longwall retreating below the 5900-ft. level was vigorously- pushed. This longwall retreating system was suggested by Mr. Rice as a possible remedy and was heartily endorsed by the company officials. This paper describes the conditions and happenings subsequent to Mr. Rice's report and more especially the results with the longwall retreating system of mining under the peculiar circumstances pertaining to mining. No. 2 Seam, Springhill, at depth, and records the 'conclusions which experience with several severe bumps under this mode of extraction would suggest. Except where necessary to make the paper intelligible as an entity any duplication of Mr. Rice's report will be avoided.

Jan 1, 1929

By Z. F. Oszter

This paper discusses the materials handling problems encountered in cement plants in the areas of raw and finished product grinding and cement storage. It illustrates by examples taken from actual installations, how optimum feed rate is maintained in grinding circuits with properly applied bin dischargers (vibrating hoppers, Mexican feed boxes and aerated bin bottoms) for materials with high moisture content and/or difficult handling characteristics. Initial operating problems with the equipment will be discussed and maintenance requirements will be indicated for comparison purposes. In a modern cement plant, properly functioning bins and feeders are as essential as process control, for no process control system, however sophisticated, can perform efficiently if raw materials do not flow into the plant processing facilities at the required time and rate. Most materials used in the manufacture of portland cement - such as silica sand, iron ore fines, crushed limestone, gypsum, clinker or cement itself-have difficult handling characteristics under specific conditions. High moisture content or even dampness due to condensation may create bin hang-ups, arching and ratholing, all of which result in improper functioning of the feeders or proportioning equipment. The occurrence of these problems in existing cement plants spurred a search for the corrective devices discussed in this article. The equipment investigated included bin dischargers in the form of vibrating hoppers for moist raw materials, Mexican feed boxes for clinker and aerated bin bottoms for cement. Operating experience with different types of bin dischargers showed that the actual performance of some did not come up to the expected level under prevailing operating conditions. The aim of this paper is to record the results of this experience and there- by aid designers and/or operators in selecting the most suitable equipment for their requirements. BIN DISCHARGERS (GENERAL) A discharger is a device that causes stored solids to flow out of a hopper without metering the rate of flow as a feeder does. The investigation discussed here encompasses the following types of bin dischargers used in a cement plant: (1) vibrating hoppers (horizontal motion), (2) whirlpool hoppers (horizontal and vertical motion), (3) aerated bin bottoms (air fluidization), and (4) Mexican feed boxes. Most of the bins used in the cement industry are of the plug flow type. Raw materials with difficult handling characteristics such as high moisture content may cause flow problems when fed through small openings (12 x 18 in.), even if two walls of the bin are vertical.' The most appropriate solution to these flow problems would be the installation of separate mass flow bins for the different materials such as silica sand, iron ore fines, crushed limestone and gypsum, with each bin correctly designed from test data obtained by measuring the flow properties of representative samples. However, limited storage capacity and plant space usually preclude this approach. Quantitative design of bins for flow based on measured flow properties of representative samples of the bulk solid to be handled is no longer an "engineering art," thanks to the basic research done on the flow of bulk solids in bins during the last decade.2, Where space limitations exist, however, or where improvements are being sought for equipment already installed, bin dischargers offer a satisfactory solution to flow problems. They can be applied effectively under flat-bottom bins or mounted to existing plug-flow bins with very little modification to these facilities. In both the foregoing cases, plug flow will be maintained, but the flow channel will be considerably increased so that it is larger than the discharger's bin-side diameter, and material flow can be sustained if the discharger is correctly selected. The main purpose of a bin discharger is to draw the bulk solids across the whole area of the bin outlet, to make the opening fully effective. As long as the bin-side opening of the discharger is large enough

Jan 1, 1969

By Thomas T. Read

The purpose of the following research, as originally planned, was to investigate the influence of temperature upon the plate-amalgamation process. In order to consider the amalgamation process intelligently, it was first necessary to learn the nature of an amalgam. In the performance of this task it was found necessary to consult a large volume of literature and to perform experimental investigations. The conceptions of the nature of amalgams thus obtained have so important a bearing on the amalgamation-process as a whole, as well as upon the possible influences of temperature, that it was advisable to include them in the treatment of the subject. The broader title is therefore used, even though some features of the amalgamation process have been treated very briefly and others entirely omitted, there being nothing new to present regarding them and their development not required for a clear presentation of the matter in hand. I. Historical Introduction. Gold was one of the earliest metals known to man. Occurring in the metallic state, it could be picked up in nuggets or mashed, as gold dust, from the sand and gravel of streams. Interestiag descriptions of the processes employed in early times for the recovery of gold may be found in Pliny's Natural History and in the treatise by Agricola on ores and minerals. But little progress in the treatment of the ores of gold mas possible until efficient crushing machines were devised. This want was supplied by the introduction, about the beginning of the sixteenth century, of the stamp-mill to treat the ores of Saxony. Blanket-strakes, or similar devices, were used to catch the

Jan 1, 1907

By Wilbur C. Helt, Joseph J. Yancik

Throughout the history of mankind, the principal use of coal has been to produce heat through combustion. The heat is used in many ways: to warm air space for our comfort; to provide heat or energy to power industrial processes, such as cement and steel production ; and to produce electricity. Because it is our nation's most abundant fossil energy fuel, coal in the late 20th century is on the threshold of becoming a significant source for synthetic liquids and gas energy fuels for this country. This is made possible by conversion processes which can change solid coal into various synthetic gases and liquids. These coal-derived fuels are nearly identical to the processed fuels and chemicals provided by natural gas and crude oils, which presently provide almost all the petrochemical feedstocks and energy fuels needed for the residential, light commercial, and transportation markets. A revolution is beginning to take place, not only in the United States, but in many other countries with a return to a coal-based energy economy. Also, new combustion and conversion technologies which are compatible with national health and environmental goals are rapidly emerging. These technologies will allow coal's use to be expanded not only in its traditional markets, but also to supply markets held by natural gas and crude oil. With the worldwide decline in natural gas and crude oil reserves, coal is being looked upon to meet the energy demand. Because of these new coal conversion technologies, coal will no longer be only a combustion fuel, but a valuable raw material for production of a variety of clean fuels and chemicals. MARKETS FOR COAL: PAST AND FUTURE A simplified diagram of the marketing network for coal is shown in Fig. 1. As shown in this figure, coal is transported to its traditional

Jan 1, 1981

By J. E. Walstrom

While intensive research continues to promote a more complete understanding of the potential and resistivity measurements that comprise the electric log, it is believed that consideration should also be given to translating these numerous and often widely separated findings into a coordinated and readable body of fundamental facts designed specifically for the petroleum engineer and geologist. Although provision is made through publication for a ready exchange of new theoretical concepts. it is also desirable to provide reviews and appraisals of the more established techniques and methods from the operating standpoint so that an economic and practical application may be realized concurrently with the theoretical progress. With these basic premises as a guide the author reviews the presnt state of electric log interpretation. The paper is directed not so much to the logging or research specialist as to the petroleum engineer and geologist to whom the electric log is only one of the many tools which he employs. Frequently, these persons do not have the time to follow in detail the many specialized contributions that appear and, as a consequence. are not in a position to place these contributions in proper relation to each other, or to the art as a whole. The paper reviews the basic steps in making quantitative determinations from the electric log of the amount of oil or gas present in subsurface formations and also discusses the degree of reliability of these determinations under various conditions. The paper also indicates the trend of future developments in electric logging systems and methods of interpretation. INTRODUCTION The electric log has been used about 20 years as a means for studying the formations penetrated by a well bore. The first half of this period is characterized by the development of suitable logging techniques and equipment. Although progress in this direction is continuing at a satisfactory rate, the last ten years are characterized more by an increasing interest in methods of electric log interpretation. During this period, a large number of fundamental papers have been published, expounding various logging techniques and particular phases of the interpretation problem. Many of these papers represent important contributions, and a few are classic. This paper is an effort to outline as concisely as possible and in simple terms the main course of progress in electric log interpretation. More specifically, it is the purpose of the paper to review the necessary elements and basic steps used in making quantitative determinations of water saturation from the electric log; and to point out the degree of reliability of these determinations under different conditions. It is strongly advised that the operating staffs of the drilling and exploration departments of oil companies cooperate wholeheartedly with both the electric logging service companies and research organizations in the testing and development of new logging systems and interpretation methods. One purpose of the paper is. however, to indicate the degree of caution which must be exercised in placing confidence in new techniques and interpretation methods that have not been thoroughly tested in the field. It is entirely possible to be cooperative in trying new methods and yet reluctant to believe in the results until the methods are firmly established. It is important to define the meaning of quantitative electric log interpretation. In the most general sense, an interpretation of the log has been made when the electrical characteristics of the formations, as portrayed on the log, have been translated into terms describing the formation geometry, rock type, or any other physical characteristics of the formations. The determination that the top of a sand is at a certain depth is an interpretation of the log. Structural determinations made by correlating electric logs from a given area are also interpretations of the logs. The term quantitative interpretation, however, will be used in this paper in the restricted sense to indicate the determination of the water saturation of a formation. This determination defines the fluid content of an oil and gas productive formation only if the porosity is known, and it assumes that the remainder of the pore space contains hydrocarbons. This assumption is believed to be true for most oil and gas productive formations. The quantitative electric log interpretation may he said to be a determination of the fluid content only to the extent which the water saturation, under the conditions given above. defines it. THE BASIC STEPS The fundamental steps in calculating water saturation from the electric log are: 1. Determination of the true resistivity of the formations from the apparent resistivities as recorded on the electric log.

Jan 1, 1952

Jan 2, 1976

By George K. Foster, Charles D. Borror

THE Jeffrey mine of the Canadian Johns-Manville Co., Limited, is in the town of Asbestos, situated approximately 100 miles northeast of Montreal and about the same distance southwest of Quebec, in Richmond County, Quebec. Mining operations were started in 1881 on outcrops on a hill, as a side-hill cut, followed by a second and third cut. This development was the forerunner of the present large open-pit operations, the mine now ranking as the largest openpit asbestos mine in the world. Operations were first carried on by hand, then by horsepower and later by stem cableways. By 1924 the derrick spans, 2000 ft. or more long, became unwieldy. To overcome this, and also to eliminate hand labor as much as possible, steam shovels and railroad haulage were introduced. The steam shovels were replaced in 1928 by larger electric shovels of the full-revolving type. THE ORE BODY The ore body is a serpentinized peridotite rock mass. The chrysotile fibers form a network of veins throughout, varying from microscopic width to two or more inches measured across the veins (Fig. I). These veins may be continuous for a few or many feet; they may increase or decrease in width within a few feet. The veins in which the fibers occur perpendicular to the veins are known as cross fiber. Those in which the fibers lay parallel to the veins are known as slip fiber. The cross fibers are of better quality, and more in demand. The majority of the fiber [ ]

Jan 1, 1946

Jan 1, 1881

By John S. Johnson

The maintenance cost, or renewal cost, in any preparation plant is a large item of expense and reflects in the total cost of producing and preparing the ton of coal. It is given constant study to the end that ways and means of controlling and reducing this proportion of the total cost may be developed. Study of this item of cost has proceeded along usual lines, which are: proper functioning of the maintenance organization; systematic and thorough inspection to prevent breakdonns; the making of repairs before renewals are needed; maintenance work done thoroughly the first time, instead of patching, study of parts needing frequent renewal or repairs or conditions resulting in delays, thorough knowledge of cost by the mall responsible for maintenance; and the use of special equipment and materials. This paper is to deal with special equipment and materials to reduce the maintenance cost hut before going into that I want to express an opinion on the general subject. Maintenance Organization Usually maintenance is taken care of by a group of men who perform their work on the off shift. The work is arranged by the operating official who should be thoroughly familiar with maintenance, so that materials needed may be made up for the particular job and waste of time in looking up materials be prevented. To perfect the maintenance organization, all operating attendants should be thoroughly trained to be familiar with all working parts of their equipment, to make a thorough inspection and to write out the slip for the work required. This requires job analysis, but it is worth the effort, because the attendant usually is better informed than anyone else about his particular equipment. The operating official can judge the scope of the work to direct the repair and to have material ready. Lubrication is an important item in maintenance, and a subject by itself. Usually the breaker oiler is designated to perform this task. This man should be picked for his ability and put in line for promotion to machinist. He should be trained as an inspector, as he is constantly visiting most parts of the breaker and has an opportunity to observe needed maintenance. The first thing is to lay out maintenance work and arrange to have it done; the next is to check the work and see that it has been properly done. This check should be made by the operating official, and through the attendant. The cost statement showing the various items of maintenance cost is not often understood by the man in direct charge. Cost sheets should be simplified and worked up by breaker sections; e.g., the cost of

Jan 1, 1947

By John S. Johnson

The maintenance cost, or renewal cost, in any preparation plant is a large item of expense and reflects in the total cost of producing and preparing the ton of coal. It is given constant study to the end that ways and means of controlling and reducing this proportion of the total cost may be developed. Study of this item of cost has proceeded along usual lines, which are: proper functioning of the maintenance organization; systematic and thorough inspection to prevent breakdonns; the making of repairs before renewals are needed; maintenance work done thoroughly the first time, instead of patching, study of parts needing frequent renewal or repairs or conditions resulting in delays, thorough knowledge of cost by the mall responsible for maintenance; and the use of special equipment and materials. This paper is to deal with special equipment and materials to reduce the maintenance cost hut before going into that I want to express an opinion on the general subject. Maintenance Organization Usually maintenance is taken care of by a group of men who perform their work on the off shift. The work is arranged by the operating official who should be thoroughly familiar with maintenance, so that materials needed may be made up for the particular job and waste of time in looking up materials be prevented. To perfect the maintenance organization, all operating attendants should be thoroughly trained to be familiar with all working parts of their equipment, to make a thorough inspection and to write out the slip for the work required. This requires job analysis, but it is worth the effort, because the attendant usually is better informed than anyone else about his particular equipment. The operating official can judge the scope of the work to direct the repair and to have material ready. Lubrication is an important item in maintenance, and a subject by itself. Usually the breaker oiler is designated to perform this task. This man should be picked for his ability and put in line for promotion to machinist. He should be trained as an inspector, as he is constantly visiting most parts of the breaker and has an opportunity to observe needed maintenance. The first thing is to lay out maintenance work and arrange to have it done; the next is to check the work and see that it has been properly done. This check should be made by the operating official, and through the attendant. The cost statement showing the various items of maintenance cost is not often understood by the man in direct charge. Cost sheets should be simplified and worked up by breaker sections; e.g., the cost of

Jan 1, 1947