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By J. Lyndon Rosenblad

The strength of a jointed-rock mass is not well-understood. It is believed, however, that the behavior of a rock mass is governed by both the intact rock properties and the properties of the discontinuities. Rock research in the past has been concentrated on the determination of intact rock properties. Several studies are presently underway which should provide more insight into the properties of the discontinuities. Few research programs, however, have been undertaken with the intent of studying the composite rock mass behavior where either the intact rock strength or the properties of the discontinuities may control failure. There are three approaches available for studying the behavior of a rock mass, namely, field studies, mathematical models (finite element), and geomechanical models. A geomechanical model has been developed in this study where the strength and failure modes of a model rock mass are studied as a function of intact block geometry, joint orientation, joint properties, and confining pressure. The objective of this study is to gain some insight into the parameters that govern the behavior of a rock mass, which parameters are most important, and when these parameters control. This chapter describes only one phase of the study, the development of equipment for use with the rock-blocks model. The models being tested are approximately 22 x 22 x 6-in. The size varies slightly depending upon the joint orientation used. The equipment developed includes model material molds, reaction frames, loading apparatus, measuring and recording instrumentation, and other accessory equipment pertinent to the operation of a successful study. The usual problems in equipment development, such as uniformity of load application, loading capabilities, and reaction capacities are all

Jan 1, 1970

By R. Hogg

INTRODUCTION As mineral particles are made smaller and smaller, it follows that their surfaces assume a greater and greater importance. In the extreme, the colloidal systems are characterized by the complete dominance of surface over bulk properties. Surface characteristics and properties will clearly influence any fine-particle processing operation. Comminution, for example, is a process of creating new surface. Agglomeration, on the other hand, may involve the reduction of surface area and the forces involved are generally surface forces. All mineral separations, solid-solid as well as solid-fluid, involve the treatment of two or more phases (solid plus liquid and/or gas). As the interfacial area increases, so will its effects on processing. Both physical and chemical separations are influenced by interfacial phenomena. Gravity separations are usually performed in a liquid phase and may be affected, for example, by the wetting characteristics of the solids. Flotation processes, of course, are based on the exploitation of differences in surface properties. Hydrometallurgical processing usually involves interfacial chemical reactions, e.g. leaching. The rates of such reactions depend on surface area and may be influenced by electrochemical effects in the electrical double layer at the solid-liquid interface, or by adsorption of reactant and/or product species from solution. In characterizing a mineral surface, it is important to consider first the surface area, since this determines the relative importance of the interfacial effects. The structure and chemical composition of the surface, which may depend on segregation of impurities within the solid and on adsorption from the external environment as well as on the bulk composition of the solid, will generally determine such

Jan 1, 1980

By R. Costantini

Long-distance transportation of solids by hydraulic pipelines holds promise of great economic benefits. In most mineral processing plants today, moving of solids in slurry-form by pipeline is commonplace. Yet in spite of this, the method is slow in being adopted on a broad scale for moving solids over distances of many miles. This is especially surprising in view of the successful realization of two daring ventures in long-distance solids pipelines in this nation within the last five years. One is the 72-mile long, 6-in. diam. pipeline of the American Gilsonite Co. which has been satisfactorily transporting 700 tpd of gilsonite from the mine at Bonanza, Utah, to the processing plant at Grand Junction, Colo., since April 1957. The other is the 108-mile long, 10-in. pipeline of the Pittsburgh Consolidation Coal Co., which has been transporting about 4000 tpd of finely crushed coal from the mine at Cadiz, Ohio, to the Eastlake Power Plant of the Cleveland Electric Illuminating Co. since January 1958.

Jan 8, 1961

By J. S. Crump, C. R. Hocott, A. E. Hoffman

Planning of the efficient operation of a gas-condensate reservoir requires a knowledge not only of the gross phase behavior of the system but also of the equilibrium distribution of the various components between the gas and condensate phases. This equilibrium distribution can be calculated with appropriate equilibrium constants. In this paper are presented equilibrium constants determined experimentally for the oil and gas phases initially present in the same reservoir and for the gas and condensate phases of the gas cap material at a series of pressures below the original reservoir pressure. Also presented is a method for the correlation of the experimentally determined equilibrium constants. The utility of the correlation is demonstrated further by an example of its use in adjusting the equilibrium data to permit their application to another gas-condensate system of similar composition. INTRODUCTION Planning of the efficient operation of a gas-condensate reservoir requires a thorouugh knowledge not only of the gross phase behavior of the particular hydrocarbon system but also of the equilibrium distribution of the various components between the gas and condensate phases. At the initial conditions of reservoir temperature and pressure, the original hydrocarbon materials in a gas-condensate reservoir or in the gas-cap of an associated reservoir exist in a single, homogeneous vapor phase. However, some condensation of hydrocarbons to a liquid phase usually occurs in the reservoir as pressure declines incident to production. Because of this condensation. the produced gas changes composition continuously. The composition of the produced gas, as well as that of the condensed liquid, can be calculated from the composition of the original reservoir material through the application of appropriate equilibrium constants or "K"-values provided these values are known. Equilibrium constants have been used for many years in problems of surface separation of gas and oil and natural gasoline recovery. However, no satisfactory equilibrium data at reservoir conditions have been available for the higher boiling hydrocarbons which acquire abnormal volatility at high pressure and are therefore present in the gas phase in condensate reservoirs. Early work in this field indicated that the behavior of the higher boiling hydrocarbons largely determines the behavior of gas-condensate systems at high pressure.' Consequently, a portable test unit was designed to permit determination of the distribution of the heavier hydrocarbons between the gas and liquid phases of a gas-condensate system. This paper describes the test equipment and presents the results of an investigation of the reservoir fluids from an associated oil and gas reservoir in the Frio formation in Southwest Texas. Also presented is a method for correlation of the experimentally determined equilibrium constants, together with an example of the use of the method in adjusting these data for application to another gas-condensate system of similar composition. FIELD TESTING AND SAMPLING In order to determine the compositions of the reservoir fluids, field samples were secured from two different wells, one completed in the oil zone, and one completed in the gas cap. The oil well was completed through perforations in 51/2-in. casing at a depth of 6,822-6,828 ft subsea. Pressure and temperature traverses made in the well indicated the pressure and temperature to be 3,831 psig and 201 °F, respectively, at a depth of 6.828 ft subsea. Subsurface samples were taken from this well after a four-hour shut-in period.

Jan 1, 1953

By A. H. Miller

THIS survey is one of the more recent tests of geophysical methods of prospecting by the Dominion Observatory and the Geological Survey of Canada, of which the purpose is to find out what application such methods may have to geological problems in Canada. The Malagash salt deposit lies on the north shore of Nova Scotia about 40 miles east of the New Brunswick boundary, and forms a part of faulted and folded Carboniferous strata. The salt beds are exposed only in the mine workings, which are about 1000 ft. deep and at one place extend for 1000 ft. along the strike. Lack of rock exposures, complicated folds, and faults make it impossible to predict the location of salt away from the mine. A survey of an area in the vicinity of the mine was therefore undertaken to find out whether the salt could be located by the torsion balance and whether its extension from the mine workings could be traced. As the gravitational effects at Malagash may be fairly typical of those at other concealed salt deposits in the Carboniferous rocks of the Maritime Provinces of Canada, the survey has a direct bearing on prospecting for other deposits. The survey was made in 1934 by A. H. Miller in collaboration with Dr. W. A. Bell, of the Geological Survey of Canada. Observations began on June 15 and were completed four months later, on Oct. 15. Definite gravitational effects including a lowering of gravity were observed over the deposit. The survey also disclosed one other area of low gravity east of the mine but whether this area is underlain by a large body of salt is not yet established.

Jan 1, 1936

By Thiann R. Yu, William J. Quesnel

At Kidd Creek, the annual production of 4.5 million tonnes of ore has been achieved primarily with sublevel blasthole stoping. This mining method has allowed underground operations to meet the designed production capacity while maintaining an outstanding safety record. To achieve this goal, rock mechanics principles have been integrated into each facet of mining in the planning stage, in the production stage, and in various stages of ground support. This paper evaluates the two adopted mining sequences based on ground stress patterns, blasting control, ground reinforcement, backfill support, and numerical modelling for stope stability at the mines.

Jan 1, 1984

By G. Rowan, M. W. Clegg

The basic equations for the flow of gases, compressible liquids and incompressible liquids are derived and the full implications of linearising then discussed. Approximate solutions of these equations are obtained by introducing the concept of a disturbed zone around the well, which expands outwards into the reservoir as fluid is produced. Many important and well-established results are deduced in terms of simple functions rather than the infinite series, or numerical solutions normally associated with these problems. The wide range of application of this approach to transient radial flow problems is illustrated with many examples including: gravity drainage of depletion-type reservoirs; multiple well systems; well interference. INTRODUCTION A large number of problems concerning the flow of fluids in oil reservoirs have been solved by both analytical and numerical methods but in almost all cases these solutions have some disadvantages — the analytical ones usually involve rather complex functions (infinite series or infinite integrals) which are difficult to handle, and the numerical ones tend to mask the physical principles underlying the problem. It would seem appropriate, therefore, to try to find approximate analytical solutions to these problems without introducing any further appreciable errors, so that the physical nature of the problem is retained and solutions of comparable accuracy are obtained. One class of problems will be considered in this paper, namely, transient radial flow problems, and it will be shown that approximate analytical solutions of the equations governing radial flow can be obtained, and that these solutions yield comparable results to those calculated numerically and those obtained from "exact" solutions. It will also be shown that the restrictions imposed upon the dependent variable (pressure) are just those which have to be assumed in deriving the usual diffusion-type equations. The method was originally suggested by Guseinov,1 who (a) postulated a disturbed zone in the reservoir, the radius of which increases with time, and (b) replaced the time derivatives in the basic differential equation by its mean value in the disturbed zone. In this paper it is proposed to review the basic theory leading to the equations governing the flow of homogeneous fluids in porous media and to consider the full implications of the approximation introduced in linearising them. The Guseinov-type approximation will then be applied to these equations and the solutions for the flow of compressible and incompressible fluids, and gases in bounded and infinite reservoirs obtained. As an example of the application of this type of approximation, solutions to such problems as production from stratified reservoirs, radial permeability discontinuities; multiple-well systems, and well interference will be given. These solutions agree with many other published results, and in some cases they may be extended to more complex problems without the computational difficulties experienced by other authors. THEORY In order to review the basic theory from a fairly general standpoint it is proposed to limit the idealising assumptions to the minimum necessary for analytical convenience. The assumptions to be made are the following: 1. That the flow is irrotational. 2. That the formation is of constant thickness. 3. Darcy's Law is valid. 4. The formation is saturated with a single homogeneous fluid.

By C. F. Knutson, Martin Felsenthal, J. D. Lung, J. D. Sudbury

This paper has been written to summarize the laboratory and field studies leading to injection of Pacific Ocean water into the Third Grubb formation. Laboratory tests for studying the permeabilities of cores to Pacific Ocean water are described. Resu1ts of these tests showed that the water could be successfully injected if it is chertzically stable, sterile, and properly filtered. Clay swelling was shown to be a comparatively minor factor in permeability reduction. Studies leading to development of an economical system for properly conditioning the ocean water are discussed. It was necessary to control pH, calcium carbonate deposition, bacterial growth, iron solubility. oxygen, and suspended .solids. A relatively simple system combining the use of sulifur dioxide, a quaternary rlmmonium chloride, and filtration was shown to adeqrrately control all these factors. This combination has not previozrsly been used as a water treating technique. Evaluation tests of the water conditioning system prior to injection are described, and results of such tests are presented. Control measures needed to insure a continusously adequate water treatment are reviewed. INTRODUCTION The utilization of sea water for waterflooding has only recently been attempted. Knowledge of treating requirements has been limited, and in most cases no water treating has been done. Prior to the initiation of the Third Grubb zone pilot water flood at Ventura, Calif.,1,2 extensive laboratory research was done in an effort to define the treatment necessary to provide a suitable injection fluid. Close coordination and cooperation between field and research personnel were found to be the foremost requisites in developing the most economical and practical method for treating ocean water. LABORATORY STUDIES Plugging Tendencies of Untreated Ocean Water A program of laboratory studies was initiated for the purpose of evaluating whether ocean water could be injected into the formation for prolonged periods of time without causing plugging of the pore spaces of the formation. Because of the fairly low permeability of the formation (averaging about 40 md), it was realized from the outset that a water of exceptionally high quality was needed. Ocean water used in the laboratory studies was carefully filtered through ultrafine fritted glass filters, having nominal maximum pore sizes of 1.4 microns. Permeability tests were then performed on representative core material from the formation. It soon became apparent in these tests that filtration alone was not a sufficient treatment for the ocean water. Prolonged injection of the filtered water caused rapid plugging of the core samples. The permeability decline of a typical sample is illustrated by Curve A in Fig. 1. The several factors which can contribute to this plugging tendency are briefly reviewed below: Interaction with Formation Clays An evaluation of clay swelling effects on liquid permeability was made using core samples from the Grubb formation. An oil was chosen for determining the reference liquid permeability because it would not tend to react with any clays that might be present in the formation. The samples were then extracted, dried, and resat-urated with either treated ocean water, formation water, or fresh water. Permeabilities to the various waters were then determined. Results of this test series are summarized in Fig. 7. The difference between the oil permeability and water

Jan 1, 1957

By Charles F. Johnson

A pulse technique is described for the measurement of bar velocity. A low frequency sine wave pulse is used which allows the wave-length to become much larger than the lateral dimensions of the test specimen. The low frequency pulse method has been tested and compared with the resonant frequency method and the results show that both methods give, on the average, equivalent velocities.

Jan 1, 1971

By A. H. Miller, G. W. H. Norman

This survey is one of the more recent tests of geophysical methods of prospecting by the Dominion Observatory and the Geological Survey of Canada, of which the purpose is to find out what application such methods may have to geological problems in Canada. The Malagash salt deposit lies on the north shore of Nova Scotia about 40 miles east of the New Brunswick boundary, arid forms a part of faulted and folded Carboniferous strata. The salt beds are exposed only in the mine workings, which are about 1000 ft. deep and at one place extend for 1000 ft. along the strike. Lack of rock exposures, complicated folds, and faults make it impossible to predict the location of salt away from the mine. A survey of an area in the vicinity of the mine was therefore undertaken to find out whether the salt could be located by the torsion balance and whether its extension from the mine workings could be traced. As the gravitational effects at Malagash may be fairly typical of those at other concealed salt deposits in the Carboniferous rocks of the Maritime Provinces of Canada, the survey has a direct bearing on prospecting for other deposits. The survey was made in 1934 by A. H. Miller in collaboration with Dr. W. A. Bell, of the Geological Survey of Canada. Observations began on June 15 and were completed four months later, on Oct. 15. Definite gravitational effects including a lowering of gravity were observed over the deposit. The survey also disclosed one other area of low gravity cast of the mine hut whether this area is underlain by a large body of salt is not yet established.

Jan 1, 1938

By G. W. H. Norman, A. H. Miller

This survey is one of the more recent tests of geophysical methods of prospecting by the Dominion Observatory and the Geological Survey of Canada, of which the purpose is to find out what application such methods may have to geological problems in Canada. The Malagash salt deposit lies on the north shore of Nova Scotia about 40 miles east of the New Brunswick boundary, arid forms a part of faulted and folded Carboniferous strata. The salt beds are exposed only in the mine workings, which are about 1000 ft. deep and at one place extend for 1000 ft. along the strike. Lack of rock exposures, complicated folds, and faults make it impossible to predict the location of salt away from the mine. A survey of an area in the vicinity of the mine was therefore undertaken to find out whether the salt could be located by the torsion balance and whether its extension from the mine workings could be traced. As the gravitational effects at Malagash may be fairly typical of those at other concealed salt deposits in the Carboniferous rocks of the Maritime Provinces of Canada, the survey has a direct bearing on prospecting for other deposits. The survey was made in 1934 by A. H. Miller in collaboration with Dr. W. A. Bell, of the Geological Survey of Canada. Observations began on June 15 and were completed four months later, on Oct. 15. Definite gravitational effects including a lowering of gravity were observed over the deposit. The survey also disclosed one other area of low gravity cast of the mine hut whether this area is underlain by a large body of salt is not yet established.

Jan 1, 1938

By J. D. Pennock

The different samples of brick examined were Grecian magnesite, American magnesite; silica brick and coke-oven tiling made in Belgium and used in retort coke-ovens. The Grecian magnesite was furnished by a New Pork party. The American magnesite and the silica brick were furnished by a manufacturing company in Pittsburgh. From these brick were made cylindrical cores, '79 inches long and 15/8 inches in diameter. At one end of each was drilled a hole about 1/4-inch in diameter and 11/4 inches long, into which the thermometer was inserted during the experiment. Conductivity.—The apparatus used for determining the conductivity, as shown in Fig. 1, is a sheetriron drum, 18 inches in diameter and 8 inches high. In the center is a little combustion-chamber with walls of split fire-brick, 39 inches square and about 6 inches high. The fire-brick, however, pass through the drum to the table on which the drum stands. The cores are placed horizontally, half-way between the top and bottom of drum and on the line of diameters at right angles. In the four walls of the combustion-chamber are cut holes just large enough to allow the cores to pass through. The cores extend

Jan 1, 1897

By Robert S. Archer, Zay Jeffries

It is about fifteen years since the development in Germany, largely by Alfred Wilm, of the aluminum alloy called duralumin. In this alloy, combining as it does the tensile strength of mild steel with the lightness and corrosion resistance of aluminum, a distinctly new material was presented to the engineering world. Despite the evident usefulness of this material, however, its commercial development has been slow, due in part to the difficulties involved in its fabrication. In view of the potentially great utility of strong aluminum alloys, it seemed desirable to find means of producing such alloys with better fabricating properties, and work was undertaken with this object in the laboratories of the Aluminum Company of America several years ago. This work has resulted in the production of two new types of aluminum alloy of the "strong alloy" class, having distinctly improved fabricating qualities. The knowledge gained has also made it possible to produce alloys of the duralumin type with greater strength and hardness than previously obtained. There have thus been made available some new engineering materials which it is the object of this paper to describe. These alloys, induding duralumin, are fundamentally wrought alloys. Castings of the same compositions heat treated in the same manner give inferior physical properties, particularly as to ductility. The statements made subsequently concerning properties and heat treatment apply to material that has received sufficient working to thoroughly break down the cast structure. The material referred to has, in general, undergone a reduction in section of at least 80 per cent, by mechanical working. It may be mentioned in passing that other compositions have been found that are suitable for the production of the maximum physical properties in heat-treated castings.

Jan 1, 1925

GEOLOGY is of service to man in two general ways according to Heinrich Ries in The Scientific Month-ly. The first of these is in exploring and evaluating the mineral resources on which industry and civiliza-tion are built, and the second is the application of geo-logic principles to various lines of human activity, such as engineering, agriculture, chemistry, etc. Both of these are phases of economic or applied geology, but neither could be developed before geology as a pure science was more or less firmly established, and in this process it freely acknowledges its indebted-ness to some of its older sister sciences such as chem-istry, physics, botany and zoology. Chemistry and geology are mutually helpful. Various chemical industries consume large quantities of raw mineral products, but since these vary in their purity and composition, it is important for the chemist to be familiar with the irregularities of composition which the different types may show, because he is often called upon to pass judgment on new sources of supply. Here geology helps the chemist. On the other hand, the laws of physical chemistry which the chemist has worked. out are of great assistance to the geologist in explaining many geologic processes.

Jan 7, 1927

By John C. Nigro

The Bureau of Mines is investigating the use of pulverized coal as a fuel for iron ore pelletizing to determine its effectiveness as a substitute for natural gas and oil. Experimental data illustrates the application of both a gun-type suspension burner and a cyclonic-type slagging burner to a grate-kiln pelletizing unit. In addition, experimentation with a cyclonic fired external combustion chamber for possible adaptation to a shaft or straight grate pelletizing furnace is discussed. The tests were conducted in the Bureau of Mines Twin Cities Metallurgy Research Center's pilot plant with high rank bituminous coals from Kentucky and Colorado and low rank subbituminous coals and lignites from Montana, Wyoming and North Dakota. Although combustion was excellent with the suspension burner, the low ash fusibility temperature coals and lignites caused some kiln ringing and accretion buildup in the grate kiln transfer section which were not encountered when firing with the high ash fusibility temperature Kentucky coal. Pellet contamination by coal ash was not deemed substantial. Problems with the cyclonic burner and external refractory combustion chamber centered around (a) maintaining complete combustion of the coal within the burner, (b) molten slag attack on the lower refractory chamber resulting in erosion of the lining and increased slag viscosities, and (c) freeze-up of the slag tap hole.

Jan 1, 1977

By C. A. Queener, W. L. Mitchell

In recent years bismuth telluride has received considerable attention, primarily due to its value as a thermoelectric material. Since there seems to be little dependence of thermoelectric effect upon crystal orientation1 many of those who have previously worked with this material have been unconcerned with knowing its crystallographic angles to any degree of accuracy. However, when one studies deformation modes, lattice stresses, or the aniso-tropy of mechanical properties of a material, knowledge of the interplanar angles and their relationships as depicted in a stereographic projection becomes essential. Lange2 originally published crystallographic data which described the structure of bismuth telluride as rhombohedral with the space group A more recent work by Francombe3 presented data which corroborated and refined the original findings of Lange. In addition, Francombe established that there is no coexistence of rhombohedral and hexagonal lattices in bismuth telluride as was suggested by Vasenin and Konovalov,4 and that the structure can be treated as a pseu do hexagonal structure with an axial ratio, c/a, of 6.95 for convenience of presentation and study. The interplanar angles and standard projections for several unalloyed hexagonal metals have been previously published,5-9 but the present work appears to be unique in that it presents data for a rhombohedral compound in pseudohexagonal form. As a pseudohexagonal structure, this material has an extremely large axial ratio as compared to the usual range of approximately 1.5 to 1.9 for the hexagonal metals. Since the interplanar angles are a function only of c/a, the angular relations between various planes for Bi,Te3 will be grossly different

Jan 1, 1965

By R. C. Hyslop

THE object of this experiment was to obtain a usable set of field curves for determining the susceptibility of rocks with the vertical magnetometer. The need often arises for determining the susceptibility of rocks in the field in order to interpret magnetic anomalies obtained. This is particularly true when diamond drilling has been done and the relation to the surface rocks of the samples taken is desired. Many methods of measuring rock susceptibility have been developed, but in general they require careful shaping of the sample or pulverizing it in addition to delicate laboratory measuring instruments designed for the purpose. The requirements for a practical method for the determination of susceptibilities are as follows: I. There should be as little alteration as possible of the specimen. 2. A minimum of time should be required in the preparation of the specimen and the calibration of the equipment. 3. The equipment used should be portable. 4. An accuracy within the limits of the survey at hand should be obtainable. 5. A means of measuring the remnant magnetism should be available. LABORATORY PROCEDURE With these ideas in mind, the problem was approached in the manner in which Koenigsberger1 developed his method using the principle of the electrical theory of images of Lord Kelvin and applying it to the magnetic case. This solution of the problem states that the apparent change [ ] in the magnetic field intensity due to the proximity of a specimen is given by: [ ] Where k is the susceptibility of the specimen, m the strength of the pole of the needle, and a its distance from the surface of the specimen, as shown in Fig. I.2 This relation is true only for an infinite body and corrections are necessary for a finite body. Koenigsberger used in his work a variometer of special design. He suggested that a Schmidt vertical balance or horizontal magnetometer, as well as some other instrument, might be used. The Colorado School of Mines horizontal torsion magnetometer operates on this principle. In the

Jan 1, 1941

By C. E. Berry

NATURAL stone or manufactured porcelain pebbles are used as the grinding elements in pebble mills and the mills are lined with stone or porcelain blocks. Steel balls usually form the grinding medium in ball mills, and the mills may he lined with steel. Pebble mills are used to avoid contamination by metal of the material being ground, to avoid rapid wear due to corrosion, and for other specialized reasons. Belgian silex (silica) blocks formerly were used widely for lining pebble mills, because of their good resistance to wear, light color, and low cost, but the importation of these blocks was suspended early in the war. The stocks of Belgian silex diminished so rapidly that it was found desirable to compare the properties of a number of domestic substitutes for use in critical operations. Accordingly, a study was made to determine the best substitutes for fine grinding of white pigment and for certain heavy-chemical process work such as the disintegration of phosphate rock in weak phosphoric acid solution. A comprehensive survey of substitute lining materials was not contemplated. It was stipulated at the beginning of the investigation that only materials on the market, available in large quantities, would be tested and that these should be reasonable substitutes from a wear-resistance viewpoint as determined from known physical characteristics. Marble and limestone, for example, could be eliminated immediately. Quartzite, granite and porcelain were selected as likely substitutes for Belgian silex and were subjected to quality tests. MATERIALS TESTED I. Belgian Silex.-Sample blocks of a standard grade were taken from crates in which they had been imported. The stone was light gray in color and contained inclusions of small clusters of quartz crystals as well as light colored portions that might be calcite. This was a siliceous rock which appeared to be of igneous origin. 2. Quartzite.-Samples of quartzite were obtained from a quarry in Minnesota. The blocks exhibited a crystalline fracture. The stone was pink in color and composed of fine quartz crystals bound together with a siliceous cement. 3. Granite A was a fine-grained granite quarried in South Carolina. 4. Granite B was coarse-grained granite quarried in South Carolina. 5. Granite C was a coarse-grained granite quarried in North Carolina. 6. Porcelain A.-Sample blocks of the pebble-mill lining material were obtained direct from the manufacturer. It was white in color and of lower specific gravity than the natural materials. It did not have a crystalline structure. 7. Porcelain B.-Sample pebble-mill lining blocks of the porcelain were received direct from the manufacturer. It was white

Jan 1, 1946

On Feb. 16, 1948, the Board of Directors of AIME authorized the publishing of "Technical Notes" in METALS TECHNOLOGY. The purpose is to provide prompt publication of wry short items of the following general types: 1. Results of short investigations which do not warrant a paper. 2. The conclusions of extensive investigations of insufficient general interest to justify a regular paper. 3. Conclusions arising in the course of an investigation, which, because of interest to others in the field, the author wishes to present prior to completion of the investigation. 4. Pertinent factual comment (not mere argument) on the subject matter of previous "Notes." Such Notes will be subject to the approval of the Auxiliary and AIME Publications Committees, but can be handled more promptly than regular papers because they need not be referred to readers. The recommended maxi- mum length is 500 words; notes in excess of 1,000 words will not be considered for this type of publication. A graph or photograph may be included as part of the note when particularly illustrative. As with regular papers, contributions to the new section should be submitted to the Secretary of the AIME.

Jan 1, 1948

By Stanley Kesler

The first of two initial 650-mw units of the Paradise Steam Station, located on the banks of the Green River in the south-central portion of the western Kentucky coal basin, is scheduled for operation in late fall of 1962. This plant will be the eighth large-capacity, modern station built by TVA in a series starting with Johnsonville, operated first in 1951. During the subsequent ten years, unit sizes have increased from a capability of 125 mw to 650 mw at Paradise. This new unit will take its place in a power system that serves an area of about 80,000 sq miles with a present installed capacity of over 12,000 mw. Upon completion of the Paradise units and other additional hydro and steam units presently under construction, the system capacity will have reached over 15,000 mw. Projected load estimates indicate that this system will provide a margin of slightly under 10% of dependable capacity above peak demand at that time. One Paradise 650-mw unit at that time will represent approximately 4yc of the total system installed capacity.

Jan 10, 1962