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By T. M. Geffen, H. N. Hall

One-third to one-half of the original oil is left in most reservoirs even after thorough gas driving or waterflooding. In contrast, essentially all of the oil contacted con be recovered by flooding with a solvent (a fluid miscible with the reservoir oil). It is not economical to fill a reservoir with solvent since the value of the solvent would very likely exceed that of the oil. A practical method would be to inject a small bank of solvent to displace the oil. This solvent bank in turn could be driven through the rock by a less valuable scavenging fluid, such as natural gas which is also miscible with the solvent. Such a method of oil recovery was studied in the laboratory using long (up to 95 ft) core systems. It was found that, as the solvent moves through the reservoir, the front end of the solvent bank becomes mixed with the oil and forms a relatively short mixing zone between undiluted crude oil and pure solvent. An engineering correlation was obtained which can be used to predict the length of this zone. Displacement of the solvent by natural gas can be achieved with complete miscibility (above the critical pressure of the gas-solvent system at reservoir temperature) or with partial miscibility at lower pressures. Under conditions of complete miscibility, it was found that the length of the gas-solvent mixing zone could be predicted from the correlation developed for the solvent-oil mixing zone. With partial miscibility, two phases exist and the solvent is displaced by a modified gas drive in which vaporization and condensation occur. Equations are developed to predict the performance of this type of displacement. Two plans are suggested for application of miscible fluid displacement. one for miscible displacement of the solvent and the other applying to lower pressures where partial miscibility occurs during solvent displacement. Calculations based on the laboratory tests indicated that a bank of solvent with a volume of less than 10 per cent of the hydrocarbon volume under consideration will generally be adequate to obtain high oil recovery from the portion of the reservoir contacted in miscible fluid displacement. INTRODUCTION The conventional methods by which oil is displaced from reservoir rock—solution gas drive, conventional gas drive, and waterflooding—are all processes in which the oil is expelled from the rock by direct displacement with a fluid immiscible with the oil. Because of the immiscible type displacement, complete recovery of the reservoir oil is not achieved. In economically successful flooding operations, as much as 50 per cent of the original oil may be abandoned in the reservoir as unrecoverable. The use of a solvent (miscible with oil, such as LPG) as an injection fluid does not have the undesirable displacement features common to the use of gas or water (immiscible with oil). It can be readily appreciated, however, that it would not be economically feasible to displace the oil and entirely replace it with a solvent. A process was therefore devised for use in field operations in which only a small volume of solvent would be required to obtain essentially complete oil recovery in the portion of the reservoir contacted. In this process, the solvent acts as a buffer between the reservoir oil and injected gas, allowing the natural gas to displace indirectly the oil with much greater efficiency than if the gas displaced the oil directly. DESCRIPTION OF OIL RECOVERY PROCESS The solvent oil recovery process will be described in

Jan 1, 1958

By Peter N. Blakey, Thiann R. Yu, Douglas O. Tansey

A flexible, efficient, and relatively low-cost drilling and blasting operation has evolved at Texasgulf Canada, Ltd.'s Kidd Creek underground mine. Located 32 km (20 miles) north of historic Timmins, Ontario, the underground operation utilizes a sublevel open stoping method developed with large-diameter blastholes. Over the years, Kidd Creek engineers have experimented with various drill-and-blast techniques, leading to the present-day practice. Continuing work is being conducted to further mechanize the blasting operation.

Jan 6, 1976

By W. G. Lidman, H. J. Hamjian

' I HE fabrication of many materials from powders involves a sintering process. A mass of powder will sinter because of the excess free energy over the same mass in the densified state caused by the higher total surface area of the powder. An understanding of the kinetics and mechanism of sintering should assist in improving the properties of such materials. The present investigation conducted at the NACA Lewis laboratory deals with the sintering of chromium carbide. Dry sintering (sintering at a temperature below the melting point) was divided into two stages by Shaler:' the first stage, during which the particles preserve much of their original shape and the voids are interconnected, and the second stage, during which densification occurs and the pores are isolated. The mechanism of forming interfaces between particles, or welding together of particles, has been investigated by Kuczynski2 and may be described by any one or a combination of the following mechanisms: viscous flow, evaporation and condensation, volume diffusion, or surface diffusion. The mechanism by which pores are closed or eliminated (densification) during sintering, is of interest. Grain growth observed during sintering may be attributed to the variation in the surface energies of individual grains, causing some grains to grow at the expense of others. Grain boundary migration occurs presumably by a diffusion process, therefore the rate of grain growth would be expected to increase exponentially with increasing time and temperature. Thus, for practical sintering times of less than 1 hr, a certain minimum temperature may exist at which major structural and property changes will occur. Densification and kinetics of grain growth during sintering under pressure of chromium carbide were investigated to provide additional information which will aid in describing more accurately the sintering process and the mechanisms involved. This material was selected for this study because of the current interest in high strength, oxidation resistant refractory materials, such as carbides, which are sintered to produce solid, dense materials from powders. Sintering under pressure is a process where the heat and pressure are applied to the compact simultaneously, specimens for this work were prepared by sintering under pressure at different temperatures and for various time periods. Experimental Procedure Preparation of Specimens: Chemical analysis of the commercial chromium carbide used in this investigation was as follows: Cr 86.19 pct, C 12.14 pct, and Fe 0.2 pct. X-ray diffraction powder patterns gave characteristic diffraction lines of Cr3C2 crystal structure. Powder particle size was determined microscopically and the average initial particle size was 6 microns with 85 pct between 2 and 10 microns. Specimens sintered under pressure were formed in graphite dies3 heated by induction. Sintering temperatures were measured with an optical pyrometer by sighting into a 3/8-in. hole drilled 1 in. deep at the midsection of the graphite die. A load of approximately 1 ton per sq in. was applied to the powder. The die assembly was heated in 20 min to the highest temperature (2500°F') at which no increase in grain size could be observed, and less than 2.5 min were required to heat from this temperature to the maximum temperature (3000°F). Sintering temperatures and times for the specimens of this investigation are indicated in Table I. Analysis of Specimens: Specimens polished with diamond abrasives were etched to reveal the grain boundaries with a 1:1 mixture of 20 pct potassium hydroxide and 20 pct potassium ferricyanide heated to 160°F. Representative areas of each sample were photographed at 1000 diameters. The largest diameters of all well-defined grains were measured, but only the measurements of 15 of the largest grains were averaged in order to determine an index of grain size on the assumption that they were among the first to begin growth. Densities were determined from differential weighing of the samples in air and water. The reported density values are considered correct within ±0.01 g per milliliter. Results and Discussion Metal compacts have exhibited grain growth when sintered at temperatures about two-thirds of the absolute temperature of their melting point.' Grain growth also occurs during the sintering of chromium carbide and is illustrated by the micrographs shown in Fig. 1. These micrographs were prepared from specimens sintered for 90 min at temperatures ranging from 1371°C (2500°F) to 1648°C (3000°F). Average grain size and density measurements of specimens investigated are presented in Table I. The relationship between grain size and sintering tem-

Jan 1, 1954

By Louis G. Bailey

This paper .reviews some of the key developments which have been made in the synthesis of the III-V compound semiconductors and the associated progress in obtaining high-quality material for device development. The history of the investigation of the semi-conducting properties of these materials has indicated the need for synthesis techniques capable of producing rnaterial of high chemical purity and physical perfection. The progress in the area is described, and the present status of quality of several compounds is discussed. In addition, recent studies of localized epitaxial deposition of GaAs into semi-insulating GaAs substvates for the development of arrays of devices ave reviewed. In conclusion, some important areas for future research and developrnent are discussed. INTEREST in III-V compounds as semiconductors dates back to the period 1950 to 1952, when Goryunova, Ioffe, and, in particular, Welker determined that 111-V compounds were structural analogs of the group IV elements carbon, silicon, germanium, and tin and that they were also semiconductors.'-3 Since that time interest in the properties of these materials has ex- panded rapidly. During 1953 and 1954, the first reports of rectification, photoconductivity, and optical absorption in these materials came from several investigators. In 1955, recombination radiation from samples of GaAs, InP, and GaSb was reported by ~raunstein .' This radiation was produced by injected minority carriers from point and large-area contacts. From 1955 to 1960, efforts increased on preparing large, pure specimens of these materials for the study of basic physical phenomena and device exploration. By 1960, materials preparation and the understanding of the physics of some of the materials had advanced to where some very interesting and potentially useful phenomena came under study. The first observation of electric-field-induced changes in the optical absorption edge (Franz -Keldysh effect) of 111-V compounds was reported for GaAs by Moss in 1961.' In 1962 the study of recombination radiation advanced rapidly. Keyes and Quist6 and Pankove and Berkey-heiser7 reported high radiative efficientices obtained from recombination, and then the first injection electroluminescent lasers in GaAs were announced by Hall ef al.,' by Nathan et al.,O and by Quist ef al.,'O and in Ga(As, P) alloys by Holonyak and Bevacqua." Hil-sum has reviewed the early work leading to the first observations of laser action in GaAS." Recombination processes in GaAs, Gap, and the other 111-V com-

Jan 1, 1968

By Donald H. McLaughlin, Reno H. Sales

ADAPTATION to mining needs of the rich store of geologic knowledge concerning mineral deposits and the application of principles of the science to specific problems in the finding, development and stoping of particular ore bodies are the major tasks of the mining geologist. On him to an increasing degree is placed responsibility for estimation of ore and appraisal of mineralized ground, for explicit guidance of exploration and development, and for reliable advice with regard to the many geologic conditions that influence mining operations. In the long continued and steady efforts to meet these requirements, a special skill in close observation, recording, and quantitative interpretation has been developed, particularly by geologists on staffs of mining companies, which in many districts has proved to be effective, not only for technical ends, but also for advancement of scientific understanding. The foundations for mining geologic work were laid in most districts of the West by investigations of the United States Geological Survey. For years they have provided a reliable basis for geologic thought with regard to ore deposits, and later studies have enriched and supplemented rather than superseded them. In very few districts have the geologic relations stated in the earlier papers needed serious modification or revision, in spite of new evidence subsequently made available in abundance by mining exposures. Indeed, one of the chief satisfactions derived from success in mining geologic work is the assurance that it gives of the correctness bf the major concepts of the science of ore formation, established to so large an extent by the leaders of this notable group among whom Lindgren has been so eminent a figure. The geologists of the Survey have given and are continuing to give the service which can properly be expected of the Federal government. Their work, however, though of the greatest value in establishing the broad geological setting,

Jan 1, 1933

By J. L. Gregg

RECENTLY there has been considerable interest in the production and use of, extra hard alloys composed primarily of tungsten and carbon. Dr. Hoyt's recent paper1 gives a good description of these alloys and describes their performance when used as tools. There are a number of these alloys on the market sold under various trade names, and it is the purpose of this paper to describe the results of an investigation of the structure of five of these alloys by means of microscopic and X-ray methods. The samples studied were in the form of small tools or wire-drawing dies, which were either purchased or supplied as samples. They were in some cases not supplied by the original makers but were furnished by the agents in this country, and we wish to call attention to the fact that they may not be truly representative of the materials supplied under the various trade names. No performance data are given and no inference as to the inferiority of one alloy as against any other is made K Schröter2 recently described methods for polishing alloys of this type for microscopic examination and has presented photomicrographs of several alloys. However, he did not identify their constituents or describe methods for their identification.

Jan 1, 1929

By W. A. Wood, H. L. Wain, R. I. Garrod

The mechanical behavior of recrystallized chromil~m of high purity has been studied, principally in torsion and to a lesser extent in tension, at temperatures between —196oand 350oC. Depending upon the conditions of test, the material may show brittle or ductile behavior or an intermediate or subduc-tile state having some of the characteristics of each. This latter state existed at temperatures between approximately ±50°C and was characterized by a) extensive creep at stresses well below the normal fracture stress, b) nonelastic loading/unloading effects during creep, c) strain softening under cyclic loading, and d) final failure of a brittle type. Suggestions are made on the dislocation processes and interactions which give rise to subductile behavior The ductile-brittle transition in bee metals has been studied mainly by tension and bend tests. These methods, however, favor crack propagation which may follow too closely on initiation for detailed study of the transition itself. For work of this nature, therefore, other modes of deformation less favorable to crack propagation may be preferable. This paper describes a study of the ductile-brittle transition in chromium which is based mainly on torsional testing although a few subsidiary experiments were made in tension. It appears to reveal at the transition an intermediate state that cannot properly be described as either brittle or ductile. Torsional tests on chromium have been made by other workers1 but not, as here, primarily for study of this intermediate state. EXPERIMENTAL The chromium, in the form of swaged rod, was prepared by techniques already described.' The particular material used was one in which the main impurities were 0.03 wt pet 0 and 0.006 wt pet N and one in which transition from ductile to brittle states in torsion conveniently fell at about room temperature. For torsion, test specimens were from 5/16-in.-diam rod to provide test portions 1-1/4 in. long by 7/32 in. diam, a twist of 1 deg thereby corresponding throughout this paper to 0.0015 surface shear. The specimens before test were annealed for 2 hr at 1200°C in vacuo, which left them with a re-crystallized grain size of about 0.01 mm, and then electropolished. They were tested under dead-weight loading in an apparatus in which they could be surrounded by a furnace or cooling chamber, tests in practice being made at various temperatures between -196" and +350°C. For tension tests, cylindrical specimens were prepared in a similar manner and tested at room temperature under dead-weight loading. RESULTS (TORSION) Subductile State. The state described above as intermediate between brittle and ductile may be perhaps best defined by reference to torque/twist curves at various temperatures. These are grouped in Fig. 1. Below about -50°C the material was brittle, in the sense that it exhibited little plastic deformation under stress and fractured by cleavage along planes of maximum resolved tension, which in torsion produces the well-known helical type of fracture. The deformation is typified by the curves for -196" and -150°C in Fig. 1; it shows a slight but progressive deviation from linearity above a certain torque, here about 50 lb-in., until fracture occurs at about 95 lb-in. A feature to which it is desired specially to call attention is that under none of the loads did the specimens show significant creep.

Jan 1, 1964

By M. A. Dayananda, R. E. Grace, P. F. Kirsch

Ternary diffusion experiments were carried out at 750°C with vapor-solid diffusion couples in single-phase copper-rich Cu-Zn-Sn alloys. The Philibert-Guy method was used to calculate intrinsic diffusion coefficients at compositions corresponding to the plane of inert markers imbedded in the diffusion couples. Inter diffusion coefficients were determined at common composition points of intersecting diffusion paths. Intevdiffusion coefficients were also obtained at compositions corresponding to maxima in the tin concentration pvofiles Relations between the interdiffusion coefficients and the expansion of vapor-solid diffusion couples are described in detail. Such relations permit the calculation of constant interdiffusion coefficients in binary couples from expansion data directly. In ternary couples expansion data provide an additional constraint on the interdiffusion coefficzents. ThE phenomenological analysis of diffusion in ternary solid solutions has been developed extensively, and various approaches taken in the determination of diffusion coefficients have been reviewed recently by Guy et al.' Finite,' semi-infinite,3 and infinite4 diffusion couples have been used in studies of ternary diffusion, but most of the work has been done with infinite diffusion couples. Semi-infinite diffusion couples3 (vapor-solid couples) have been used to determine both intrinsic and interdiffusion coefficients in the Cu-Zn-Mn system, in which two diffusing species, zinc and manganese, were supplied from the vapor phase. If only one component has a sufficiently high vapor pressure to be supplied from a vapor source, vapor-solid diffusion couples may still be used. In this case the boundary conditions at the gas/solid interface may be governed by partial equilibria rather than by virtually complete equilibrium between the phases. In the present work diffusion measurements were carried out at 750°C with vapor-solid couples of Cu-Zn-Sn alloys. Only zinc was transported between the vapor source and the diffusion disks, because the vapor pressures of both copper and tin are at least 108 lower than that of zinc. Both intrinsic and interdiffusion measurements were made at several compositions. A secondary objective was to relate expansion of the diffusion couples with the interdiffusion process. Such measurements for binary couples yield average values of the interdiffusion coefficients over composition increments. In ternary diffusion couples ex- pansion data provide an additional constraint on the interdiffusion coefficients. COMPOSITION-DEPENDENT INTRINSIC AND INTERDIFFUSION COEFFICIENTS As shown by Philibert and GUy5 the determination of intrinsic diffusion coefficients in a ternary system requires two independent diffusion couples containing marker planes with identical composition. In the case of vapor-solid couples such a requirement torresponds to two couples set up with the same vapor source exposed to two diffusion disks of different composition. Inert markers placed initially on the disk surfaces become imbedded during diffusion. If the pair of couples exhibits appreciable marker burial with marker planes of virtually the same composition, the intrinsic diffusion coefficient may be evaluated at the composition of the marker planes. Fig. 1 is a schematic diagram of the concentration of of a Cu-Zn-Sn ternary vapor-solid couple after diffusion of zinc from a vapor source into a binary Cu-Sn alloy. The areas, Ai correspond to the cumulative intrinsic fluxes of the three diffusing species across the marker plane:5 where Ji is the intrinsic flux of component i, t is the diffusion time, and D3i are the intrinsic diffusion coefficients. For the determination of interdiffusion coefficients a pair of diffusion couples with intersecting diffusion paths is needed. At the composition point of intersection (C1, C2) the coefficients are evaluated from the equation:3

Jan 1, 1969

By G. A. Colligan, G. L. F. Powell

A new experimental technique has been developed to study nucleation behavior in eutectic alloys. It is somewhat similar to that applied by Sundquist and Mondolfo1 but with the advantages that: 1) bulk samples are undercooled instead of small droplets thus allowing the thermal behavior to be monitored by a thermocouple immersed in the sample, and 2) nucleation behavior is investigated in the same sample on either side of the eutectic composition by adding additional component to the sample under controlled conditions which preclude the addition of nu-cleation contaminants. Sundquist and Mondolfo carried out ]nucleation ex-periments on a large number of eutectic alloy sys-tems and concluded that nonreciprocal nucleation operated. If one phase a was a good nucleant for the other phase 0, then B was a poor nucleant for a. This was determined experinlentally by comparing the nucleation temperatures of 100 to 300 u diameter droplets of hypereutectic and hypoeutectic composition cooled from above the liquidus and from a temperature between the liquidus and the eutectic temperature. Primary phase a was concluded to be an efficient nucleant for the other phase B, if the following experimental result was obtained. Referring to Fig. 1, the temperature TI at which a drop of hypereutectic alloy of composition B froze when cooled from above the B liquidus was noted. This was the nucleation temperature for B in the absence of a. A drop of hypoeutectic alloy of composition A was then frozen from temperature T2 between the a liquidus and the eutectic temperature. The temperature T3 at which the eutectic nucleated in the presence of the primary or proeutec-tic a was noted. If this temperature T3 was higher than the temperature TI at which the B nucleated in a hypereutectic alloy, it was concluded that the primary a had nucleated the 6. This temperature T3, representing a certain undercooling below the equilibrium eutectic temperature Te , was designated ?TB by a> the undercooling below T, for nucleation of 13 by a. If there was no substantial difference in nucleation temperature between the hypereutectic drop cooled from above the /3 liquidus and the hypo-eutectic drop cooled from a temperature between the a liquidus and the eutectic temperature, it was considered that the a nucleated B at an undercooling equal to or greater than that at which P nucleated from a hypereutectic alloy. Sundquist and Mondolfo1 found that faceted primary crystals were good nucle-ants for metals that grow as orthogonal dendrites when present as the primary phase. Jackson2 has questioned Sundquist and Mondolfo's technique and proposed that in Sundquist and Mon-dolfo's samples, such as composition A, primary a retained B in reentrant grooves at their surfaces when heated to a temperature above the eutectic but below the a liquidus. This objection was suggested by experiments with organic eutectics where reten-

Jan 1, 1970

By Mary Louise Theodore, R. G. Aspden, D. A. Colling

T RACES of sulfur have a marked influence on the physical and mechanical properties of many iron-base alloys. The commonly used combustion method for the determination of sulfur content is not accurate enough at the 50 ppm level by weight and below to be useful in determining the influence of sulfur. Kriege and Wolfe' have described a method for the determination of sulfur in iron alloys in which the sulfur is evolved as hydrogen sulfide followed by reaction with N, N-dimethyl-p-phenylenediamine, and iron (111) to form methylene blue which is measured spectrophoto-metrically. This method of determining sulfur has been used to study the activity of sulfur in Fe-Si-S alloys,' but has not been previously applied to the determination of sulfur in Fe-Ni alloys because of the insolubility of nickel in dilute hydrochloric acid. Dissolution of nickel in dilute hydrochloric acid, however, can be greatly accelerated by the addition of a small amount of platinic chloride.3 By combining these two techniques in a procedure in which 0.005 pct platinic chloride in 1:l hydrochloric acid is used as the dissolving fect on the strength of the material. However, ductility is influenced by the presence of discontinuous precipitation. In Fig. 5, percent elongation data at room temperature and 1400°F is shown for two sets of specimens of Waspalloy which were solution heat treated at 1950°F and either quenched or slow cooled to the aging temperature and then aged for 100 hr at 1292" and 1598ºF, respectively. At room temperature the existence of a discontinuous precipitation cell at grain boundaries (see data point marked by arrow) has no apparent effect on ductility. However, at elevated temperatures a pronounced lowering of ductility occurs when discontinuous precipitation has occurred in the specimen. It would appear that the morphology of discontinuous precipitation "cells" at grain boundaries would be highly conducive to the initiation of cracks which in turn lead to premature "grain boundary" failure.

Jan 1, 1970

The Goodman Mfg. Co., Chicago, builders of underground electric mining machinery, celebrated its 50th Anniversary on April 23rd. The company has a complete line of cutting machines, loaders, conveyors, locomotives, and shuttle cars for service in both coal and metal mines. The Joy Mfg. Co. has received, under the provisions of the Economic Cooperation Administration, an initial order in excess of $1,000,000 for equipment to be used in the mechanization of iron ore mines in France. While the equipment will be used in various privately owned mines, the order was placed through the French Society for the Development of Mechanical Mining. Included in the equipment are the company's recently developed hard rock loaders and shuttle cars. American Brake Shoe Co. has consolidated all operations of its Canadian subsidiaries into one corporation, the Dominion Brake Shoe Co. Ltd., Montreal, Canada. The products of Dominion Brake Shoe include brake shoes, track equipment, manganese steel castings, automotive brake lining, air compressors, and paint spray equipment. Exhibits of more than 2000 electrical products, processes, and techniques, ranging from precise aircraft instruments to complex working models of steel mill, textile and other industry equipment, will be displayed in the "More Power To America Special" when it makes its nationwide tour this spring. C. H. Lang, Vice-President in charge of sales for General Electric's apparatus department, said that the train will visit the country's key industrial centers for inspection by utility and industrial executives and municipal leaders. The train will be hauled by an Alco¬G-E two-unit, 4000-hp., Diesel-electric locomotive which in itself will be part of the unusual series of displays. Sizing of Excavators and Hauling Equipment. The Power Crane and Shovel Association has released a 24-page bulletin dealing with the proper sizing of excavators and hauling equipment, Technical Bulletin No. 3. Rubber Conveyor Belting. "Installation, Care and Maintenance of Rubber Conveyor Belting" is the title of a booklet just published by the Carlyle Rubber Co., New York. Power Transformers. The manufacturing procedure of Allis-Chalmers small power transformers is described in a new 28-page bulletin, 61B6094A, covering the core and coil unit, no-load tap changer, tank construction, cooling methods, oil preserving systems, bushings, terminal compartments, indicators and testing of transformers. Safety Equipment. General Scientific Equipment Co., Philadelphia, has released a 46-page, fully illustrated catalog on personal protective equipment and industrial safety devices. This new catalog covers respiratory devices, eye protection, hats, gloves, carboy pumps, drum pumps, and miscellaneous safety equipment for use in mines, industries, etc. Osmosalts. The Osmose Wood Preserving Co., Buffalo, N. Y., has issued a bulletin on Osmosalts, the wood preservative which, say the manufacturers, makes timber last three to five times longer, slashes maintenace costs, stops rot, and resists wood-destroying insects. Jigs. The Dorr Co. has acquired the Pan American jigs and they are now known as the Dorrco-Pan American jigs. Originally developed as a gold-saving device for dredges, the simplicity, ease of operation. efficiency, and negligible maintenance of these jigs have resulted in wide adoption on all types of placer operations, in the closed grinding circuits of gold mills, and on many applications where a coarse bed concentrate is separated from the ore gangue.

Jan 5, 1950

TWENTY-FOUR of the 28 local sections and the two divisions of the Institute were represented at the meeting. Three sections failed to appoint delegates and two of those appointed failed to attend the delegates' meeting proper. Four sessions were held, two on Monday and two shorter adjourned ses-sions on Tuesday and Wednesday. Even at the end many things remained to be said and, in view of the amount of time the delegates lost from technical ses-sions the feeling was general that next year it would be advisable to hold their meeting the day before or day after the general meeting. Every part of the country was represented from Boston to Los Angeles and Seattle to Washington. All phases of Institute work and policy were taken up in the most informal way and the delegates will carry back to the sections, as they brought to headquarters, many ideas that will prove useful and stimulating. The time was divided between reports by the delegates on section activities and reports by officers of the In-stitute and of the various joint activities on the work at headquarters : A. D. Flinn told of the work of Engi-neering Foundation; W. V. Brown discussed the Em-ployment Service; J. A. Sohon explained what the Library is doing; T. T. Read told how the sections could help MINING AND METALLURGY ; H. Foster Bain discussed Institute affairs in general and asked and answered questions. An interesting new feature of the meeting was the appearance by request of Directors Turner and Smith of the U. S. Bureau of Mines and U. S. Geological Survey to answer inquiries as to the needs and work of their Bureaus. So much attention had been paid this year by the western sections to the diminished funds made available at Washington for research on mining problems that many questions came up. The accom-panying figures epitomize the answers.

Jan 3, 1928

By R. F. Sheldon

Largest uranium deposit in the Northwest is Dawn Mining Co.'s Midnite mine on the Spokane Indian Reservation. The orebodies lie along the contact of granite and metamorphosed sedimentary rock and are controlled by faults and shear zones near the granite contact. In the oxidized zone the deposits consist mainly of the secondary uranium mineral meta-autunite; sooty uraninite and primary uranium minerals are known to occur at greater depths. Elevations in the mine area range from 2500 to 3500 ft. The rolling hills and low, rounded mountains are covered with grass and evergreen trees. HISTORY AND DEVELOPMENT Original showings were discovered with a geiger counter in the spring of 1954 by prospectors Jim and John LeBret. High radioactivity in several schist outcrops was found due to scaly coatings of a greenish-yellow, fluorescent mineral, later identified as meta-autunite. Prior to this time autunite was not known to occur in the state of Washington, and no significant uranium deposits had been found in the Pacific Northwest. Outcrops in the area were few, and most of the ground was mantled with 2 to 10 ft of overburden, but three other radioactive zones were discovered by prospecting the ridge southward along the strike of the schist near its contact with granite for three quarters of a mile. Midnite Mines Inc. was formed

Jan 1, 1960

By Tkeoclore Marvi

IT is singular that an industry quite the antithesis of flying should record tremendous strides in the utilization of aviation through- out the entire depression period, .while in the same years private interests lagged and airplatie manufacturing plants closed to such an extent that he purchase of new planes of certain types was practically impossible. Though receiving little notice from aviation publications and national associations, this use of the airplane progressed by sheer merit. It saved money, conserved energies, and made minutes in the air the equal of weeks on foot or water. The advent of aviation into mining and petroleum operations dates back many years, yet it \vas not until the depression that this new facility of the mineral industry was put on its proper economic basis. There, by its possibilities for saving effort, time, and money, it takes its place equally with other great technical advances in nietl

Jan 1, 1934

By W. J. Taylor

In making heating gas with anthracite coal for roasting ore during the past few years, I have tried many forms of gas generators. So far, the most successful and satisfactory one has been what we call a fluxing producer, which is simply a small cupola or blast furnace, in which we charge with the coal, say, 30 or 40 per cent. of basic blast-furnace cinder, to unite, when melted, with the ash or earthy matter in the coal, and carry it off as cinder. The producer we have in use at Chester, N. J., has more of the lines of a blast furnace than a cupola, the hearth being 24 inches diameter and 24 inches high. It then enlarges on an angle of about 25 degrees from a perpendicular to 4 feet, and then is drawn into 3 feet on top ; total height, 12 feet. We use one water coil-tuyere 12 inches above the bottom, and blow through a 1 1/2 - inch nozzle. The depth of coal above the tuyere averages about 6 feet. The producer-is blown with

Jan 1, 1881

Established as a Division March 13, 1935 R H Feierabend, Chairman T E Gillingham, Jr, Northeast Vice-Chairman W A Riggs, Southeast Vice-Chairman C F Clausen, Mid-Continent Vice-Chairman R H Wilpolt, Rocky Mountain Vice-Chairman J K Brooke, Pacific Southwest Vice-Chairman Leslie C Richards, Pacific Northwest Chairman V A Haw, Canadian Vice-Chairman J S Holland, Sec'y -Treas National Lead Company Mining Department 111 Broadway New York 6, New York

Jan 1, 1960

Flexibility is the keynote in designing modern exploration drills that and mobility. Add to the flexibility of individual drills the wide range of models, and the man looking for a drill has ample choice today. Weight? Choose from models as light as 50 lb or as heavy as 10,000 lb. Hole capacity? From less than 1 in. for smallest core drills to 20 in. or more for auger types. Transportation? The lightest go by packsack (in fact, that is one trade name) ; others are designed to go by Jeep, truck, on skids or are built on light trailers. Power? Select air power, gasoline or diesel engine, electric motor, or use a power take-off from the vehicle on which the drill is mounted. Drill bits offer almost as much variety as the drilling machines themselves. Many drills are suitable for a variety of uses, and often adapt to several types of bits with ease. Some of the types available are: diamond core, diamond reaming, rotary, auger, shot, and special soil sampling tools.

Oct 1, 1955

By AIME AIME

T HE Executive Board of the American Engineering Council held its fourth meeting at St. Louis on the first anniversary of the organizing conference which met in Washington on June 3,1920. Representatives of a number of the leading engineering organizations in the vicinity of St. Louis were present by invitation. The members of the Executive Board were guests of the Associated Engineering Societies of St. Louis. They were given a delightful ride about the city and were entertained at the Glen Echo Country Club at dinner. The special committee that had been appointed to draft resolutions to Mr. Hoover submitted the following, which were adopted : WHEREAS, our President, Herbert Hoover, has been appointed Secretary of Commerce in the Cabinet of the President of the United States, and WHEREAS, in consequence of his acceptance of this high public office, he has deemed it necessary to tender his resignation as President of The Federated American Engineering Societies.

Jan 1, 1921

By R. B. Full

DURING the summer of 1949, the United Nations Scientific Conference on the Conservation and Utilization of Resources met at Lake Success. As summed up by one writer, the purpose was: "That everyone will try to learn how to feed more people from an acre of land." That objective is a stimulus to the phosphate rock industry as well as other industries. Phosphate rock was mined first in the Canadian province of Quebec where it was found as an apatite in pockets. In 1863, mining began near the Rideau Canal, first in open trenches and quarries until shafts were sunk. These operations were difficult since hard rock had to be drilled and blasted. Steam was the source of power. The phosphate rock was hand-selected and recovery ranged from 6 to 10 pct, averaging 70 pct to 85 pct bpl (bone phosphate of lime). Costs, f.O.b. Montreal, were $14 a ton, and selling prices averaged $17 a ton. In 1885, about 29,-000 tons were sold on this basis, but by 1892 the output fell to 8000 tons at an average price of $15 a ton at Montreal. South Carolina Deposits Phosphate rock was first discovered in South Carolina in 1837, but a mining company was not formed until 1867. It was immediately successful, and the industry continued to develop and ship an increased tonnage of land and river rock, shipments increasing from approximately 20,000 tons in 1868 to 537,000 tons in 1890, when the shipments began to decrease. In 1892 only 350,000 tons were shipped. In this field there were two types of deposits: land rock and river rock. More land rock tonnage was mined until about 1887 when river rock production began to equal it. The land rock was mined adjacent to and in the river marshes by pick, shovel, and wheelbarrow. Each worker dug daily a space 6 ft wide, 15 ft long and 6 ft deep, which was overburden, and then loaded about 3 cu yd of phosphate rock into wheelbarrows. His helper would wheel the barrows to small steam railroads up to 250 ft distant. Water was kept from the pits by steam pumps connected to railway cars. The phosphate rock was loaded into railroad cars, hauled and dumped into a log washer to which water was added, and run over trommel screens to eliminate the clay and loose sand. Steam shovels for loading were introduced about 1891. River rock was mined by floating dipper dredges and at low tide was loaded into barges by laborers using oyster tongs, the large lumps being hand-loaded. Barges and bateaus were unloaded by wheelbarrows which were wheeled to the same type of land rock washers. The washer product was piled with stacked pine cordwood in alternate layers and fired for drying. Usually this was done under sheds along the river bank. The dried rock then was transferred to ships, usually three or four-masted schooners. Cost of production of both land and river rock, including $1 a ton royalty paid to the state for state-owned property, was approximately $4.25 a ton averaging 60 pct bpl. The selling price was approximately $7 a ton f.O.b. In 1886 the courts handed down a decision permitting anyone to mine, and many additional companies were organized immediately. As a result, the selling price was lowered to a profit margin of 50Ø or less per ton. The South Carolina mines were eventually shut down when a more profitable source of phosphate rock was discovered in Florida. Florida Deposits Phosphate rock was discovered in Florida in 1882, and in 1883 a small quarry was opened near Hawthorne. In 1886 phosphate rock of good grade was discovered on Peace River, and the Arcadia Phosphate Co. was formed. In 1888 the company began shipments amounting to 3000 tons that year. During the latter part of 1888, hard-rock phosphate was discovered near Dunnellon. Exploration extended rapidly, and deposits of hard-rock phosphate were mined over a wide area so that shortly after 1900

Jan 1, 1952

By AIME AIME

THE time of the Section delegates was economized this year by providing the section reports in mimeo- graphed form, together with the reports of the officers and committees of the Institute, for their consideration on arrival. The meeting was called for Thursday forenoon and despite a certain amount of oratory managed to get through before all the luncheon was gone. In all, nine section delegates and one from the Iron and Steel Division attended and took part. One delegate, who had come many miles, got lost in the complication of the program and failed to attend. Six appointed dele- gates failed to attend and two sections neglected to make appointments.

Jan 1, 1929