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THE Institute assembled in the Court-House, on Tuesday evening, May 22d, and was called to order by Vice-President E. B. Coxe. After announcement by the Local Committee of the programme for excursions, the Secretary read the following annual report of the Council The Council, in presenting to the Institute its annual report, has to record a most eventful year in the history of the Institute. Three meetings, as usual, have been held, two in Philadelphia and one in New York. At the Philadelphia meetings in June and October, there were present many distinguished foreign engineers, some of whom contributed communications to the Institute, and took part in its discussions. Sixty-seven papers have, in all, been presented to the Institute, which will be published in the fifth volume of Transactions. There has been an accession to the membership of 1 honorary member, 11 foreign members, and 162 members and associates; -8 have resigned, 6 have died, and 30 have been dropped from the roll, after due notification, for non-payment of dues. The membership now comprises 5 honorary members, 60 foreign members, and 644 members and associates, in all 699. As worthy of especial mention in the work of the year are the Discussions on Technical Education in connection with the American Society of Civil Engineers, and the report of the-International Committee appointed by the Institute to consider the nomenclature of iron and steel. The Discussions on Technical Education have been published in a separate volume, and comprise a valuable and suggestive collection of the views of practical engineers and educators. The report of the International Committee, composed of Messrs. Akerman, of Sweden; Bell, of England; Tunner, of Austria; Gruner, of France; Wedding, of Prussia; and Holley and Egleston, of the United States, has received the careful attention of engineers and metallurgists of all countries, and has met . with very general acceptance. Of the work of the Centennial Committee in Philadelphia the members are generally familiar, from personal experience, and from the detailed report of the committee at the last meeting of the Institute. But the record of the service rendered by this committee would he incomplete without mention of the numerous letters of thanks and formal expressions of obligations received by the Institute from individuals, societies, and governments abroad. The wise and generous spirit in which the work of the committee was planned, and the laborious and self-sacrificing manner in which it was carried out, call for emphatic expressions of thanks from the Institute. The gifts of Centennial exhibits to the Institute, largely as testimonials for services rendered, has necessitated the appointment of a Museum Committee for

Jan 1, 1878

By R. L. Huntington, D. T. MacRoberts, Charles R. Hetherington

Since the equation of continuity governing transient flow of gases through porous media cannot be integrated mathematically into a simple usable expression free from series terms, empirical and approximate equations have been advanced relating cumulative production and future production rates from gas reservoirs with time. In order to check the accuracy of these empirical equations and to obtain an insight into the initial conditions pertinent to the solution of the fundamental equation of continuity, experimental work has been conducted on a vertical 2-in. tube, 91.6 ft. high, packed with unconsolidated Wilcox sand. The results presented in graphical form show the accuracy of the approximate relations. Data from unsteady-flow runs on the 2-in. experimental tube are presented graphically, and are applied to obtain an equation for this specific case, and are offered as an aid in future investigations of this basic equation. The close agreement between equations calculated for steady-state flow and the experiments indicates that the decline of actual gas reservoirs may be treated by an application of these equations without serious error. Introduction The steady-state flow of gas through a porous material—that is, flow wherein the boundary conditions do not vary with time—is subject to analytical solution. Muskat1 has shown that the general differential equation is simply the La Place equation in P2. Direct solutions may be at once obtained. The unsteady state, on the other hand, is not analytically reducible. Since nearly all phenomena of practical interest in gas production involve flow in the unsteady rather than in the steady state, it has been necessary to derive approximate Solutions to the general equation. The validity of such approximations has not hitherto been adequately tested. In the experiments to be described a simple, closed, linear system is substituted for the real complex gas field. The general results, however, are independent of the geometry Of the system' The problem studied is the rate of production, and the accompanying variations in pressure, when one end of a linear porous system is opened to the atmosphere and permitted to produce to exhaustion. An approximate solution to the general differential equation, based upon the assumption of an "infinite series of steady states," is then applied to the results to determine the validity of this method of dealing with actual reservoirs. Theoretical Considerations The fundamental differential equation governing the flow of a gas through a Porous medium can be derived easily from the equation of continuity, Darcy's law, Boyle's law and a statement of the thermo-dynamic nature of the flow. For isothermal flow it is: d2P2/dx2 + d2p2/dy2 + d2p2/dz2 = 2fµ/K dP-dT

Jan 1, 1942

By J. K. Stanley

It has been known for many years that the magnetic properties of a ferromagnetic material are very sensitive to internal strain. Any structure-sensitive property such as ferromagnetism, which is a function of the regularity of the atomic arrangement, and discontinuities such as grain boundaries must show deviations from an equilibrium state when the regularity of the lattice is disturbed. Experience has shown that such distortions have a marked effect on the magnetic properties of a ferromagnetic material. The purpose of this paper is to show the feasibility of using magnetic methods in detecting internal strains. More specifically, it will be shown how such properties as permeability, rema-nence, and coercive force change on cold-working of aluminum iron and how these magnetic properties change during the annealing below the recrystallization temperatures. This work was conducted for two reasons. One was the desire to see in what manner strains are relieved in aluminum iron at low temperatures—a subject of practical importance in soft magnetic materials—and the other was the feeling that a study of cold-working and strain relief might shed some light onour understandingof what takes place in the deformation of metals. Definition of Terms It is necessary to define the terminology used in this Paper because magnetic nomenclature is usually unfamiliar to the metallurgist, and certain other terms, such as recovery, have been used ambiguously by metallurgists and others. Magnetic terms are best explained by reference to the common hysteresis loop of ferromagnetic materials (Fig. I). In Fig. 1 the coordinates are magnetic induction, B, (ordinate) and magnetizing force, H. (abscissa). The c.g.s. unit for the magnetic induction is the gauss, the number of flux lines per square centimeter, and the unit for the magnetizing force is the oersted, the number of lines of force per centimeter in air or vacuum. If one starts with a completely demagnetized specimen and magnetizes it, a typical virgin magnetization curve beginning at the origin is obtained. This curve is also the locus of tips of a family of smaller hysteresis loops. From this curve it is to be noted that the induction is not proportional to the magnetizing force, and that it appears to approach a limiting induction called the saturation value, and does so for values of H of 1000 oersteds. The ratio of the magnetic induction (gauss) to the magnetizing force (oersteds) is called permeability, . Thus u= B/H and if the magnetizing force H (oersteds) is specified as ro or 100 oersteds, the permeability is written as or l00 This is the accepted notation, and will be used in this paper. The values of permeability for H = 10 or I00 are chosen as indices for 106

Jan 1, 1945

By M. T. Simnad, G. Derge, Ling Yang

STUDY of diffusion in molten substances is important in at least two respects. Diffusion data, combined with thermodynamic and kinetic information, throw light on the structure of the liquid state. Moreover, a knowledge of diffusion coefficients and their temperature dependence is useful in ascertaining the controlling step in many metallurgical reactions. Although diffusion measurements have been made on a number of molten salts, slags, metals, and alloys,'-'" the results available are still limited and widely scattered, especially for the high temperature melts. It is the purpose of this investigation to establish reliable procedures for the measurement of self-diffusion coefficients in high temperature melts and to use these procedures to determine the self-diffusion coefficients of iron in molten Fe-C alloys of different carbon contents. Experimental Measurement of self-diffusion coefficients in high temperature melts is usually carried out by using one of two methods. In the first, diffusion takes place between two cylindrical samples of the same material, one of which is made radioactive. The diffusion coefficient is calculated from the radioactivity penetration curve in the solidified sample after the diffusion. In the second method, samples contained in capillaries of an inert substance are immersed in an infinite reservoir of the same material. Either the material in the capillary or that in the reservoir is made radioactive and the diffusion coefficient is calculated from the change of the radioactivity of the sample in the capillary after the diffusion. The second method is simpler because a radioactivity penetration curve is not needed for the calculation of the diffusion coefficient; however,.it is valid only when no convection has occurred in the capillary during the diffusion. A radioactivity penetration curve is therefore always useful in indicating that the required conditions for the diffusion are ful- filled. Towers and Chipman" recently studied the self-diffusion of calcium and silicon in CaO-Al,O,-SiO, melts by using the capillary method. Instead of measuring the change of the radioactivity of the sample in the capillary, they autoradiographed the sample after the diffusion and calculated the diffusion coefficient from the intensity distribution of the autoradiograph. Their method is useful when the radioactive isotopes are weak ß-emitters, but is very difficult, if not impossible, to apply to cases involving strong ß or y-emitters. For such cases, sectioning of the sample according to the method of Morgan and Kitchener' may be used for the construction of the radioactivity penetration curve. The self-diffusion of iron in molten Fe-C alloys has been studied in this manner and the experimental procedures are described as follows: The diffusion apparatus is shown schematically in Fig. 1. The bath consisted of about 200 g of an Fe-C

Jan 1, 1957

By M. R. Goldick

THE Roan Antelope concentrator was originally designed with a nominal milling capacity of 6000 tons of copper ore per day but this was subsequently considerably exceeded. In broad outline the plant consisted of two No. 30 McCully gyratory crushers for coarse crushing, five 5 1/2-ft Standard Symons crushers in open circuit for secondary crushing, ten No. 98 Marcy ball mills arranged in five sections, each two-mill section with primary and secondary Dorr classifiers for two-stage grinding. One stage of flotation roughing was followed by two stages of cleaning, all in airlift type pneumatic flotation machines, with the final concentrates filtered on Oliver drum filters. Tailing was thickened in a 250-ft Dorr traction type thickener before pumping to the tailing dam. Concentrating operations commenced in June 1931, on the completion of the first two ball-milling sections and output was increased during the next few months as the remaining sections were finished. From the start, very few technical difficulties were experienced but a number of evolutionary changes have been made as a result of operating experience and the availability of improved equipment. These have resulted in plant and ore-flow alterations although the general scheme of ore treatment remains substantially as before. The main changes to date were the installation of a new crushing plant at Storke shaft, some 7000 ft west of the original Beatty shaft; the completion of a two-stage secondary crushing plant; an increase of 20 pct in ball-milling capacity; a change-over from pneumatic to a mechanical type of flotation machine for flotation roughing; the reduction of flotation cleaning from two stages to one stage. ORE TREATED Typically the ore treated consists of metamorphosed shales and sandstones with shales as the principal mineral-bearing rock carrying chalcocite, bornite and chalcopyrite as the main copper minerals. Chalcocite predominated in the original eastern end of the ore body but there is a pronounced trend to an increased proportion of the copper-iron sulphides as mining proceeds westward. Although the ore can be described as soft, this advantage is offset by the extremely fine dissemination of the copper minerals which calls for a high degree of comminution of the ore (90 pct minus-200 mesh Tyler standard) to give a reasonably satisfactory separation of mineral from gangue. Latterly, there has been a tendency for the ore to become harder as shown by a reduction in the ball-milling rate from a previous figure of over goo tons per ball-mill day to the present output of some 800 tons. Chalcopyrite is not so finely disseminated and has also proved more amenable to flotation than chalcocite. Nonsulphide minerals are mainly the so-called oxides such as malachite, cuprite and melaconite with some chrysocolla and

Jan 1, 1947

By S. LeFevre

, The solution of the housing and sanitation problem in mining communities, keeping in view both economic and humanitarian aspects, demands the best thought of the management of such enterprises. Upon the solution depend the health and comfort of the employee and his family, and as a consequence his contentment and efficiency. The following description covcrs briefly the methods installed for Witherbee, Sherman & Co. The operation of the system has been for about two years under the direct supervision of T. A. Hammond, Land Agent, and I am indebted to him for a compilation of the results. Sanitation The sanitary service covers 238 tenements. The installation cost was about $22 per tenement, as follows: Privy, $15; privy box, $3; proportion of incinerator cost, $2; garbage can, $2. The operating cost is $1 per month for each tenement. In considering the installation of an ordinary village system of water supply and sewerage two difficulties were encountered: First, lack of a sufficient quantity of water; there is no stream large enough, as Mineville is situated very close to the divide between the Lake Champlain and Hudson River watersheds. A storage reservoir was tried, but the only location available, among glacial hills, would not hold water. Second, the expense of digging ditches for the distribution of water and sewer pipes is so great as to be prohibitive; Mineville is built chiefly in a valley covered in the bottom with drift, in this case a combination of boulders and hard pan. Digging in this material costs 80c. to $1 per cubic yard, and pipes must be placed 41/2 ft. down to be below frost. The houses are scattered along 4 miles of streets, the oldest having been built in the original forest 65 years ago. The newer houses have gone up a few at a time wherevcr a clear space could be found and the slopes were not too steep. This has advantages, as it separates the dwellings into

Jan 1, 1915

By R. H. Smith, A. C. Polk

The physical properties of the materials are listed, together with a short explanation of how this material binds the sand grains together without materially reducing the effective permeability of the sand. The chemical can be used in wells with bottom-hole temperatures ranging from 105°F to more than 350°F A description of the equipment required and the techniques used for applying these plastics to the wells is included. Introduction Recovering oil and gas from unconsoli-dated sand formations offers one of the most troublesome of all production problems. These sands generally present no particular trouble while drilling is in progress, but after the well has been completed and a pressure differential has been established across the face of the producing zone, the formation begins to L'slough," resulting in "sanding up" of the well. The term "sanding up" means that sufficient volumes of sand have moved into the well bore or casing to cause a serious reduction or complete halt of all flow of oil, water or gas. In rare cases a well may produce only a small amount of sand and still continue to flow or pump, the sand being carried to the surface in the fluid stream. However, in such instances, the result may be a costly repair bill due to the effect of the sand on surface and pumping equipment. The difficulty of producing petroleum from sands that are loosely cemented has long been recognized by petroleum engineers but only within the last few years has any new approach to the problem been undertaken. This involves the use of plastics that are capable of bonding the individual sand grains in place without materially reducing the effective permeability of a formation. The successful application of plastics for the consolidation of poorly cemented sands is relatively recent but now it is widely used in many of the more difficult areas on the Gulf Coast of Texas and Louisiana. This relatively new use of plastics1 in the oil fields has been preceded by much laboratory and field research on the use of various chemicals2,3 for solving numerous well-completion and work-over problems. Plastics now are being used successfully to control gas-oil and water-oil ratios,4'6 in zone isolation, the repair of casing leaks, the elimination of caving in cable-tool drilling wells6'7 and in the setting of linerss and casing.9 Sand-consolidating plastics, however, are basically different from all others in that they must not form an impervious seal. Field Practices The approach to the sanding-up problem usually has been the mechanical obstruction of the movement of the sand grains.

Jan 1, 1947

By A. C. Polk, R. H. Smith

The physical properties of the materials are listed, together with a short explanation of how this material binds the sand grains together without materially reducing the effective permeability of the sand. The chemical can be used in wells with bottom-hole temperatures ranging from 105°F to more than 350°F A description of the equipment required and the techniques used for applying these plastics to the wells is included. Introduction Recovering oil and gas from unconsoli-dated sand formations offers one of the most troublesome of all production problems. These sands generally present no particular trouble while drilling is in progress, but after the well has been completed and a pressure differential has been established across the face of the producing zone, the formation begins to L'slough," resulting in "sanding up" of the well. The term "sanding up" means that sufficient volumes of sand have moved into the well bore or casing to cause a serious reduction or complete halt of all flow of oil, water or gas. In rare cases a well may produce only a small amount of sand and still continue to flow or pump, the sand being carried to the surface in the fluid stream. However, in such instances, the result may be a costly repair bill due to the effect of the sand on surface and pumping equipment. The difficulty of producing petroleum from sands that are loosely cemented has long been recognized by petroleum engineers but only within the last few years has any new approach to the problem been undertaken. This involves the use of plastics that are capable of bonding the individual sand grains in place without materially reducing the effective permeability of a formation. The successful application of plastics for the consolidation of poorly cemented sands is relatively recent but now it is widely used in many of the more difficult areas on the Gulf Coast of Texas and Louisiana. This relatively new use of plastics1 in the oil fields has been preceded by much laboratory and field research on the use of various chemicals2,3 for solving numerous well-completion and work-over problems. Plastics now are being used successfully to control gas-oil and water-oil ratios,4'6 in zone isolation, the repair of casing leaks, the elimination of caving in cable-tool drilling wells6'7 and in the setting of linerss and casing.9 Sand-consolidating plastics, however, are basically different from all others in that they must not form an impervious seal. Field Practices The approach to the sanding-up problem usually has been the mechanical obstruction of the movement of the sand grains.

Jan 1, 1947

By Walter R. Hibbard

THE term lineage was first introduced by Buerger1 to denote dendritic branches, grown from a crystal nucleus during solidification from the liquid, with imperfections in alignment of the order of 10-1 [ ] to 10-4 cm. These imperfections are associated with distortions of the dendrites caused by the subsequent solidification of the inter-dendritic filling and are illustrated in Fig 11. Buerger etched zinc single crystals made by the Bridgman2 method to develop this dendritic pattern and show lineage microscopically. Since maximum crystal growth in face-centered cubic metals occurs along the [100] directions,2 lineage would appear in copper as small deviations of dendritic branches from these directions. Elam4 and others5-8 reported etching effects resulting from coring along the cube face traces of various copper alloy crystals. These traces were used by Samans8 to orient single crystals. Williamson9 noted a "lined structure (in alpha brass single crystals) consisting of an ordered arrangement of etch pits" which were probably traces of {100} planes but somewhat uncertain because they were never straight (i.e., apparently lineage). Greninger10 described the distortion and multiplicity of Laue spots in back reflection X ray photograms of copper single crystals showing lineage. The present investigation includes metallographic, X ray and property studies of lineage in large grain and single crystal specimens of copper. PREPARATION OF SPECIMENS Specimens 10 in. long and ½ in. diam of oxygen-free copper (O.F.H.C.) (99.985 pct) were melted vertically in graphite crucibles under an atmosphere of commercial nitrogen purified through a gas train including sulfuric acid, potassium chloride, magnesium chlorate, hot copper chips and phosphorus pentoxide. After a temperature of 1200°C had been maintained for ½ hr, the furnace was turned off and the specimens cooled at a rate of about 150°C an hour. This method of direct solidification was used by Greninger10 to produce single crystals with marked lineage and in this investigation produced a fair yield of single crystal specimens in

Jan 1, 1947

By C. D Looker

Common salt is mentioned in the most ancient writings as an important article of diet. It is fairly certain that it was used by men and animals long before the dawn of civilization. Its presence in natural springs has often been the determining factor in colonization; wars have been fought for possession of salt deposits; trade routes have been established expressly for the purpose of traffic in salt. Naturally this led men into adventures and discoveries that altered history and advanced civilization. In the early days the uses for salt were few and the methods of manufacture were crude and the purity low when compared to salt of the present day. Then the salt came largely from springs, shallow wells or the ocean, while today deep wells must be drilled to the natural brines or beds of rock salt and spacious shafts sunk so that the ancient deposits may be made to yield their supply of stored mineral. Mining and Purification The quantity of available salt seems inexhaustible. It occurs in practically every country of the globe. About 20 million tons is produced and consumed annually in the world. Of this amount about 7 million tons is produced in the United States; 13/4 million tons of rock salt, 2 1/4 million tons as evaporated salt and 31/2 million tons in brine used in the chemical industry. Mined rock salt is used in its natural state without purification. It is classified for the trade by crushing and screening. The average purity of rock salt mined in the United States is about 98.3 per cent pure sodium chloride1. The usual impurities are gypsiferous shale, anhydrite and silica, with traces of potassium, magnesium and calcium compounds. Refined or evaporated salt is made by crystallizing the salt from brine in open pans or vacuum pans. A comparatively small amount of salt is made from ocean water or the brines of inland lakes or seas, sometimes by solar evaporation. By far the larger amount of brine is obtained by drill-

Jan 1, 1938

By C. D. Looker

Common salt is mentioned in the most ancient writings as an important article of diet. It is fairly certain that it was used by men and animals long before the dawn of civilization. Its presence in natural springs has often been the determining factor in colonization; wars have been fought for possession of salt deposits; trade routes have been established expressly for the purpose of traffic in salt. Naturally this led men into adventures and discoveries that altered history and advanced civilization. In the early days the uses for salt were few and the methods of manufacture were crude and the purity low when compared to salt of the present day. Then the salt came largely from springs, shallow wells or the ocean, while today deep wells must be drilled to the natural brines or beds of rock salt and spacious shafts sunk so that the ancient deposits may be made to yield their supply of stored mineral. Mining and Purification The quantity of available salt seems inexhaustible. It occurs in practically every country of the globe. About 20 million tons is produced and consumed annually in the world. Of this amount about 7 million tons is produced in the United States; 13/4 million tons of rock salt, 2 1/4 million tons as evaporated salt and 31/2 million tons in brine used in the chemical industry. Mined rock salt is used in its natural state without purification. It is classified for the trade by crushing and screening. The average purity of rock salt mined in the United States is about 98.3 per cent pure sodium chloride1. The usual impurities are gypsiferous shale, anhydrite and silica, with traces of potassium, magnesium and calcium compounds. Refined or evaporated salt is made by crystallizing the salt from brine in open pans or vacuum pans. A comparatively small amount of salt is made from ocean water or the brines of inland lakes or seas, sometimes by solar evaporation. By far the larger amount of brine is obtained by drill-

Jan 1, 1938

By M. W. Fabjanczyk, E. G. Alexander

INTRODUCTION The purpose of this paper is to summarise development of design processes used in the 1100 oreoody as a result of experience encountered. Design methods have been developed as a result of the history of ground behaviour, free-standing qualities of cemented back fill and mass blasting techniques. This paper contains an historical review of design methods previously described by Matthews ( 1972 ) , Hornsby and Sullivan (1977 and 19781, Kirkby, Blair and Hutton (19781, and Stewart (1980). The reasoning behind design philosphy changes are discussed and placed into context with methods now adopted. The 1100 orebody is Mount Isa's main producer of copper ore (5 million tonnes per year ) . Proven reserves are 120 million tonnes at 3.2% Cu. Location of the 1100 orebody in relation to overall mine geometry was well described by Dayton (1976). Geology The orebody is located in a series of massive brecciated shale lenses, in either a siliceous or dolomitic matrix, surrounded and separated by a uniform shale sequence. The whole formation is truncated at depth by a faulted contact with a greenschist facies metamorphic sequence below (Figure 1 and Figure 2) Mathias and Clark (1976). The breccia is known locally as silica dolomite and contains nearly all the economic mineralisation. Interfingering of shale and breccia often results in irregular boundaries to the silica dolomite and the ore limits. Geometry The geometry of the orebodies is shown by Figures 1, 2 and 3. Figure 3 also shows the location of the copper orebodies in relation to the lead orebodies. Structure Although the orebody is contained within the massive breccia (u.c.s. 150-250 MPa), it is cut by shear zones sub-parallel to the regional bedding (north-south striking, dipping approximately 60o to the west), and diagonally by major transverse faults (Figure A). These major faults have continuity in excess of 300 metres, with varying amounts of displacement up to 200 metres, and are zones of potential movement.

Jan 1, 1981

By Michael R. Cartwright

The Gold Acres outcrop was located by Lee Lakin in 1922, according to Mr. H. W. Treweek. There was no activity, however, until 1935, when prospect drifts and pits penetrated the deposit. It was then drilled by the Willow Creek Mining Company. Beginning in the late 1930s and continuing to the late 1940s more than 150 churn drill holes were drilled in the Gold Acres area. From this drilling came what is now known as the London Extension pit. Only oxidized ore amenable to cyanide vat leaching was mined during this time. Our records indicated that this period of mining removed some 1.4 Mt (1.5 million st) of ore at an average grade of 0.006 kg/ t (0.2 oz per st). Union Pacific and Newmont Mining Company worked in the area prior to acquisition by the Cortez Joint Venture. Union Pacific drilled a number of core holes in the area. The unoxidized nature of the ore, small tonnage, and low grade undoubtedly prevented mining at this time. From these indications of mineralization shown by previous companies, the Cortez Joint Venture developed and mined 2 Mt (2.4 million st) at 0.005 kg/t (0.15 oz per st) in the Gold Acres pit. This pit is located immediately southwest of the older London Extension pit. Cortez Gold Mines has continued to drill to the west and south of these pits along the downdip continuation of the former ore bodies. The downdip extension is unoxidized and more metallurgically difficult than the normal Carlin type ores, but, more than 2.4 Mt (2.7 million st) have been outlined. It depends now upon the gold price and milling costs to turn this mineralized area into an ore body. A possible lesson to be learned from this deposit is that continued mining success depends upon an ongoing adequately funded exploration-development-metallurgical research program. These three disciplines must always be present to locate the mineralization and to turn this mineralization into ore. [ ]

Jan 1, 1985

By J. E. Burke, C. S. Barrett

The fine lines shown in Fig I are typical of markings that ma): be detected after polishing and etching deformed specimens of alpha brass and other alloys. Although they have long been the subject of discussion by metallurgists their nature is still uncertain and the names that have been applied: to them, such as deformation line4 or strain markinas, indicate this uncertainky. In this paper which repotts the results of a furthcr investigatinn of their nature, they will be called strain mxrkings. Introduction Mathewson and Phillips1 described strain markinps in 1 916 and concluded that they appear only after 20 pet deformation. They objected to the markings being called slip tines believing this term should be sewrved for surface markings protluced by plastic deformntion. In 1921. vogel² described similar striations which appeared after polishing and etching the roughly ground surface of numerous alloys. He reported that the markings were crystallo-graphic in nature, and since they resemble Seumann hands in iron, at least superficially, he assumed them to be mechanical twins. In 1928, Matherwson reported work by Phillips which indicated that the lines were more readily produced by impact than by slow deformation and that in many cases the twins inside recrystallized grains were parallel to strain markings in the original deformed grains. This was taken as cvirlence that the markings coalesce into anncaling twins. and hence that they themselves are mechanical twins. Many attempts have been made to demonstrate directly that the markings are mechanical twins. In 1934, Samans described the results of X ray studies of two defomed crystals of alpha brass. Evidence was obtained which could be interpreted to indicate that the strain markings arc mechanical twins, and this remains the only direct evidence to this effect. Several other attempts to obtain similar evidence by X ray diffraction have failed5.8.7 although in no Ease was the original method of Samans employed. An

Jan 1, 1949

By C. S. Barrett, J. E. Burke

The fine lines shown in Fig I are typical of markings that ma): be detected after polishing and etching deformed specimens of alpha brass and other alloys. Although they have long been the subject of discussion by metallurgists their nature is still uncertain and the names that have been applied: to them, such as deformation line4 or strain markinas, indicate this uncertainky. In this paper which repotts the results of a furthcr investigatinn of their nature, they will be called strain mxrkings. Introduction Mathewson and Phillips1 described strain markinps in 1 916 and concluded that they appear only after 20 pet deformation. They objected to the markings being called slip tines believing this term should be sewrved for surface markings protluced by plastic deformntion. In 1921. vogel² described similar striations which appeared after polishing and etching the roughly ground surface of numerous alloys. He reported that the markings were crystallo-graphic in nature, and since they resemble Seumann hands in iron, at least superficially, he assumed them to be mechanical twins. In 1928, Matherwson reported work by Phillips which indicated that the lines were more readily produced by impact than by slow deformation and that in many cases the twins inside recrystallized grains were parallel to strain markings in the original deformed grains. This was taken as cvirlence that the markings coalesce into anncaling twins. and hence that they themselves are mechanical twins. Many attempts have been made to demonstrate directly that the markings are mechanical twins. In 1934, Samans described the results of X ray studies of two defomed crystals of alpha brass. Evidence was obtained which could be interpreted to indicate that the strain markings arc mechanical twins, and this remains the only direct evidence to this effect. Several other attempts to obtain similar evidence by X ray diffraction have failed5.8.7 although in no Ease was the original method of Samans employed. An

Jan 1, 1949

By H. J. Struth

A glance into the immediate future of the refining industry, and a retrospective view of 1929, cannot fail to emphasize the need for effective measures of control of refinery still runs. With oil producers alert to the need for control of the crude supply, it has become more than ever necessary for refiners to complete the movement toward stabilization by concerted determination to maintain still run schedules within the limitations prescribed by the demand for gasoline. The outlook for continued growth in the demand for gasoline appears to be well sustained by a preliminary survey of requirements for 1930. In fact, it is apparent that the industry will be assured of a market for gasoline that will aggregate in volume at least 472,000,000 bbl. this year. This indicates a gain in total demand over 1929 of about 9 per cent. or about 4.6 per cent, less than the gain recorded during 1929 over 1928, which amounted to 13.6 per cent. Despite the indicated increase in gasoline demand this year, it is apparent that little, if any, more crude will be required than last year. This is shown in Table 1, presenting estimates of gasoline demand and probable crude requirements for 1930. Table 1.—Preliminary Survey of 1930 Gasoline and Crude Run Requirements Millions of Barrels Doniestic gasoline demand................................... 397 Foreign gasoline demand..................................... 75 Total indicated demand...................................... 472 Natural gasoline content..................................... 53 Net gasoline from crude...................................... 419 Imported gasoline........................................... 13 Net gasoline required from refineries.......................... 406 Indicated excess stock Dec. 31, 1929........................... 10 Maximum protluction required................................ 396" At 40 per cent. gasolitlc recovery, this represents a maximum crude converson of 990,000,000 bbl., or a daily average for the ycar 2,712,000 barrels. Year after year, the refining branch of the petroleum industry has been found guilty of running crude to stills greatly in excess of normal requirements, causing frequent periods of market depression. A review

Jan 1, 1930

By R. S. Moehlman

IN recent years, exploration and development by diamond drilling has become a popular attack on the problem of finding new ore shoots and developing extensions of known shoots. Diamond drilling has been used in recent years in extensive sampling of disseminated copper deposits, in preference to churn drilling. At the Harvard gold mine, near Jamestown, California, Philip R. Bradley, Jr., general superintendent, reports that: "The Harvard work was a singular example of the reliance that can be placed on diamond drilling in evaluating an ore body." Drilling at the Harvard mine will be discussed in a subsequent section of the paper. So popular has diamond drilling become, indeed, that many who have had slight experience with drilling are inclined to regard it as a cheap cure-all. This paper proposes to show some of the limitations on the application of drilling and some of the steps that should be followed in drilling programs to obtain reliable results. COST OF DRILLING Drilling has the advantage, over shaft sinking and drifting, of lower cost and greater speed. As compared with churn drilling, the advantage of bringing up a coherent sample instead of fine cuttings for a sample is obvious. Diamond drilling is generally more expensive, however, and more engineering effort is required in combining the average of core and sludge samples. Exploration of drift walls by hammer drills to a depth of less than 50 ft. is generally cheaper than diamond drilling, but beyond this depth the diamond drill is cheaper and more efficient. The principal factor in determining cost of drilling is the character of the ground drilled. Broken ground with many fissures is most expensive to drill. Hard ground is less of a problem with diamond drills than with ordinary machine drills. Hardness or softness affects only the speed of drilling. Caving, easily washed, sandy or clayey ground requires continual cementing and casing, which is the greatest cost problem. Thus, soft, incompetent ground is more costly to drill than hard, massive ground. Cost of drilling per foot in good to fair ground varies from less than $1 per foot, achieved in some districts in Ontario, the Mother Lode, and Missouri, to $5 per foot in many western states. In bad drilling ground, costs may range from $5 to $15 or more per foot, thus approaching the cost of drifting. Other factors that increase the cost per foot are: I. Short total length of hole drilled, so that the cost of moving in crews and equipment must be spread over a relatively few feet. 2. Cost of drilling per foot increases with depth beyond about 500 ft., as more time is consumed in pulling rods. 3. Cost of preparing drilling stations, getting air underground to stations, etc. 4. Inaccessibility and lack of water on the job make for higher costs.

Jan 1, 1946

By J. D. A. Morrow

THIS discussion relates to the distribution of coal under the direction of the U. S. Fuel Administration beginning Apr. 1, 1918. At that time a definite method of ' controlling and directing distribution was put into effect. Prior thereto, although some of the machinery utilized was in operation, especially in the few weeks immediately preceding Apr. 1, distribution had not been effectively and comprehensively organized. The writer was called to the Fuel. Administration by Dr. Garfield about the. first of February, 1918, to assume general direction of the distribution of coal for the Fuel Administration, to develop the general plans, and to obtain practical men to assist in this work and in carrying through the program finally devised. A study of the situation and conferences with the Fuel Administrator and leading men in the business made it plain that it would- he necessary to begin at the bottom, measure the undertaking, develop plans to meet the need thus shown, and build an organization to effect the distribution required. This work had to be done under war pressure in the midst of a bad coal shortage. The successful performance of such a task is always primarily a matter of putting competent men in the right places and giving, them the power and opportunity to function properly together. In the Distribution Division of the U. S. Fuel Administration, the men who were chiefly responsible for whipping plans into practical form and then for carrying out these plans were A. W. Calloway, of Baltimore, President of the Davis Coal & Coke Co., who served as the Director of Bituminous Coal Distribution; S. Lovell Yerkes, of Birmingham, Alabama, Secretary of the Grider Coal Sales Agency, who assumed general charge of distribution while the new plans and organization were being perfected and then became the Assistant Director of Bituminous Coal Distribution; Warren S. Blauvelt, of Detroit, who was Director of Coke Distribution; A. S. Learoyd of New York, Director of Anthracite Distribution, in connection with the Anthracite Committee, consisting of Joseph

Jan 3, 1919

By M. A. Rigdon, R. E. Grace

The dissociation of cupric oxide to cuprous oxide and oxygen was studied with a microbalmce technique at 700" to 750°C. In this temperature range the dissociation pressure of the reaction 2CuO= Cu2O + 1/2 O2 was: The theory of near-equilibriwm reaction rates predicts a linear relationship between reaction rate and the Gibbs free-energy change for small values of AF/RT. This correlation is found to be valid for AF/RT = -0.1 or approximately 200 cal per mole away from equilibrium. THE theory of reaction rates near equilibrium as developed from classical thermodynamics suggests a small range of linear behavior between the overall reaction rate and the free-energy change accompanying the process. The extent of this linear correlation is generally unknown, even to the order of magnitude. The idea of linearity is also found in the formal mathematics of coupled transport phenomena, e.g., chemical diffusion, thermal diffusion, thermoelectricity, and so forth. The linear array of forces and fluxes which leads to various main and cross coefficients is predicated upon linearity between reaction rates and the bulk thermodynamics which govern the process. The general case in reaction kinetics is well-known: the magnitude of the free-energy change does not cor- relate with observed reaction kinetics, irrespective of whether the process occurs by diffusion or chemical reaction or both. The real need is to investigate specific reaction paths near equilibrium in order to learn of the limitations in attempting to correlate reaction rates and thermodynamics. It is the main purpose of this paper to examine the dissociation kinetics of cupric oxide under conditions of known driving force where the dissociation process is likely to occur by chemical reaction. A secondary objective is to obtain equilibrium data for the CuO-Cu20-O2 system. In a prior paper Edmiston and race' investigated reduction kinetics of wustite in H2-H2O gas mixtures. The present study was carried out in oxygen according to the following reaction:

Jan 1, 1969

By Barry N. Whittaker

INTRODUCTION Considerable progress has been achieved with long- wall mining in recent years especially in enabling increased rates and levels of output to be gained, higher standards of safety and increased usage of advanced technological developments. Longwall mining also has major long term advantages, prominent amongst which is general minimisation of the effects of pillars and room intersections giving rise to future instability problems as can be the case with room and pillar mining operations. The fact that longwall mining is not presently limited by depth below surface inclination of seams or thickness of seam to be worked strengthens its position as the most popular underground mining method for extracting coal seams in Europe. Its wider application in North America and Australia can give rise to significant economic benefits coupled with higher levels of safety and recovery of coal. This present paper reviews recent progress achieved and draws attention to the more important factors influencing longwall mine design and layout. LONGWALL STRATA PRESSURE ABUTMENTS A longwall gives rise to major redistribution of strata pressures. The roof behind a longwall is normally allowed to cave and permit subsidence of the overlying strata and eventually giving rise to a trough depression at the surface. Consequently, reestablishment of strata loading within the caved region behind the longwall depends upon effective caving and subsequent recompaction. This requires sufficient depth pressure and/or adequate width of extraction in relation to the depth to achieve breaking of overlying roof beds necessary to reload the extracted region. Figure 1 shows results of an analysis carried out by Whittaker and Singh (1979) indicating the pattern of redistribution of vertical stress around a longwall in the plane of the seam. The analysis represents the average depth of longwall working in the UK, and was performed using a stress balance assumption of compatibility before and after mining. The main stress abutments are indicated by (1) the front abutment strata pressure zone which travels with the longwall, and (2) the flank abutment strata pressure zone which

Jan 1, 1982