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By J. E. Hove

The high temperature physical properties of graphite are reviewed and interpreted in the light of present day knowledge of the mechanisms affecting these properties. The thermal and mechanical behaviors only are discussed and, whenever possible, comparisons are made with other refractory materials. Possible further studies are indicated, including some carbide work. AS long as the term high temperature implied only temperatures up to about 1000°C, the materials problems which arose could usually be handled by fairly conventional metal alloy types, such as the Co-Cr-Ni superalloys, for which there exists a great deal of technology. Perhaps this temperature can still be considered an upper limit for normal applications, but it is certainly true that the number of abnormal applications is increasing rapidly. The advent, in recent years, of ram-jet and rocket missiles and of high power nuclear reactor heat sources has raised a host of questions concerning the basic problem of what material to use in the temperature range up to 2000°C and higher. While there are, of course, many metals, in the second and third transition series, which melt at considerably higher temperatures than this, these metals are, at present, pretty well excluded from practical use by other considerations, such as re-crystallization, chemical activity, or excessive plastic deformation. The behavior of metals, from the standpoint of dislocation theory, is just beginning to be understood and thus there is some hope for the future development of very high temperature metals, but the immediate problems would most logically appear to have solutions involving the nonmetals, such as the refractory ceramics and graphite. For this reason, there is presently a great deal of engineering and experimental research being performed on the latter materials, much of this research being exploratory in the sense of gathering new property data. The situation, so far as graphite is concerned, is somewhat more fortunate than with the other refractory solids in the sense that a great deal is already known about its basic properties. This stems both from the fact that the carbon-carbon bond has been of interest to chemists for a long time (and graphite can be considered as a very large aromatic molecule, if desired) and the fact that its properties, both as a function of temperature and of radiation damage, are of critical importance to nuclear reactor designers. It is still true, of course, that such fundamental questions as why graphite remains solid to such a high temperature and why it has such a high thermal conductivity cannot entirely be answered at the present time. It is, nonetheless, meaningful and instructive to consider such problems in the light of existing knowledge. This is what the present paper will attempt to do. Before going on, it may be appropriate to classify graphite and justify its discussion before readers primarily interested in metals. Graphite is comparatively unique among materials in that there is always a property or group of properties which precludes calling it either a metal, a semiconductor, or a ceramic. It has the high electrical and thermal conductivities of a metal, but the artificial, poly-crystalline types show a negative thermal coefficient of electrical resistivity, generally characteristic of semiconductors. On the other hand, semiconductors, by definition, show an ever increasing resistivity as the temperature is lowered, whereas graphite approaches a finite, and, indeed, a rather low resistivity in the region of 10°K and, furthermore, a good single crystal of graphite has a positive temperature coefficient, as for a metal.' On still another hand, its porosity and brittleness at lower temperatures would put graphite in the ceramic class although, unlike most ceramics, it is readily machinable and has a high resistance to thermal shock. All things considered, it is probably more nearly appropriate to call graphite a metal than anything else. Although certainly outstanding in some ways, graphite has its peculiarities and, especially if the reader is unfamiliar with the data, it is probably valuable to review some representative property variations at high temperature. This review is meant to be mainly illustrative and no attempt has been made to be exhaustive. Review of High Temperature Properties At ordinary pressures, graphite does not melt, but sublimes directly into the gaseous phase at about 3700°C. Although the phase equilibrium diagram is still in some doubt, graphite will melt, at a slightly higher temperature, at pressures in excess of about 100 atm. The chief difficulty of using graphite in an oxidizing atmosphere is that the reaction rate becomes quite high at fairly low temperatures. If a threshold oxidation temperature2 is defined as the temperature at which graphite loses 1 pet of its weight in 24 hr, the value in air is 450°, the value in steam is 700°, and the value in carbon dioxide is 900°C. Efforts are presently being made to raise this threshold temperature either by impregnation with a retardant of some type (sodium tung-state and phosphoric acid, for example) or by a suitable metal or oxide coating. It is probably fair to say that, to date, these attempts have not shown any outstanding success in all respects. Most commercial graphites are fabricated by impregnating a carbon flour (say of coke or lampblack particles) with some type of hydrocarbon

Jan 1, 1959

By Richard T. Newcomb

Federal and utility industry research has largely ignored coal beneficiation techniques in the implementation of SOx control. This paper accepts the hypothesis that beneficiation cum scrubbing is the cheapest way for the vast majority of seams in the eastern coal provinces to comply with standards. Comparisons are based on point estimates of average beneficiation costs from a model of coal preparation (COBET) designed to simulate four levels of cleaning. The paper describes how economic theory can be applied to derive econometric supply functions from actual data on the geology of minable seams, washability and technical constraints. West Virginia is taken as an example of a producing region. Spatial supply functions are derived empirically from the engineering model simulations.

Jan 1, 1977

By C. M. Young

The safety lamp is the most common and convenient apparatus for detecting inflammable gases in mines, the presence of gas being shown by a blue flame, called the cap, if the wick has been lowered to suppress the luminous flame. The height of the cap increases with the proportion of gas and with the temperature of the lamp flame. Lamps of the Wolf type, the fuel of which is benzine, have a hotter flame than lamps in which vegetable oils are used, such as the Davy, and the Clanny, and are more sensitive than the latter and their many modifications. The Piehler alcohol lamp gives a still higher cap while the Clowes hydrogen lamp is most sensitive of all. While the effect of the temperature of the source of ignition is well known, the writer knows of no previous attempt to correlate the change of this temperature with change of the height of the cap produced, In order to determine the height of the cap at various temperatures, it was necessary to have a source of ignition the temperature of which could be accurately controlled over a considerable range. This condition was met by a coil of wire of high fusing point heated by an electric current controlled by a variable resistance. The use of a coil offered the further advantage of freedom from complications due to the flame of a burning fuel. Such a flame, being itself of variable height, would to some extent raise or lower the elevation of the base of the cap and therefore add to the difficulty of determining the height of the cap. Besides this, the presence of a small cap from the lamp fuel, commonly known as the "fuel cap," would interfere with the observation of small gas caps. After some experiment, a coil was made of platinum wire, No. 26, diameter 0.016 in. The coil was 17/64 in. (6.746 mm.) in outside diameter and had eight full turns in a length of 1/2 in. (12.69 mm.). This was connected to an electric circuit through an adjustable resistance, as shown in Fig. 1. In order to measure the temperature, a thermocouple was inserted in the center of the coil; the leads passed out at the ends and were ccnducted to a millivoltmeter. It is probable that the current of air passing upward through the coil resulted in the indication of a tempera-

Jan 1, 1920

By Walter Herd

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

Jan 1, 1929

By A. D. Schwope, L. R. Jackson, A. M. Hall

In the course of an extensive investigation of the comparative properties of several types of copper, data were obtained on the cold working and subsequent recovery and recrystallization of the copper. In this paper, relations between the degree of cold work and the course of re-crystallization are developed. In particular, it is shown that the course of recrystallization over long periods of time and at low temperatures can be predicted with reasonable accuracy from short-time high-temperature recrystallization data. Materials Used in The Investigation Three types of copper were used in this investigation; these were tough pitch, OFHC, and OFHC copper with 15 oz per ton of silver added identified herein as Lots C, D, and F, respectively. The material was supplied by the American Metal Co. Ltd., and processed by the Rome Cable Co. The analyses of the three types of copper are given in Table I. Originally, it started as wire bars 4 X 4 X 54 in. These bars were heated to 871° C in air and hot rolled to % in. rod. This rod was cold drawn to 0.204 in. rod (70 pct reduction) in three passes and annealed at 427°C for 4 hr. A portion of the 3/8 in. rod was saved for more detailed cold-drawing experiments. Starting with the annealed 0.204 in. rod, hard-drawn wires were produced by cold drawing to 0.081 in. wire in 7 passes (84.4 pct reduction in area). Half-hard wires were made by cold drawing the 0.204 in. rod to 0.102 in. wire, (75 pet reduction) in 6 passes and annealing at 427'C for 4 hr. This annealed wire was then drawn to 0.081 in. wire, (37.1 pet reduction) in 2 passes. Square rod was made by hot rolling wire bars to Re in. rod in 8 passes. This rod was then cold drawn to 0.445 in.-diam rod and annealed for 346 hr at 538°C. It was then cold drawn to 0.325 in. rod and again annealed at 538°Cf or 3 1/2 hr Hard square rods were then made by cold rolling this material to 0.257 X 0.257 in. rod, a reduction in area of 20.5 pct. Half-hard square rods were made by cold rolling to 0.268 x 0.268 in. square, annealing for 3 1/4 hr at 538°C and cold rolling to 0.257 x 0.257 in., a reduction of 8.5 pct. Soft wire or rod was made from all types of copper by annealing the hard-drawn material at 343°C for 3 hr in steam. The grain size of the annealed 0.081 in. wire varied slightly among the three lots: from o.o15+.oz5 mm in the silver-bearing OFHC to 0.035-0.045 mm in the OFHC copper. The annealed 0.257 in. wires were more uniform in grain size, averaging about 0.035-0.045 mm. Representative structures are shown in Fig I. Effect of Cold Drawing and Tensile Strain on Strength of Copper Conventional tensile tests were performed on the three types of copper in the various degrees of hardness described above. Results of these tests are tabulated in Table 2. The results in Table 2 are 6

Jan 1, 1949

By Regis M. N. Pelloux, N. J. Grant

Five or six alloys each in the systems Ni-C.v, Ni-Mo, and NL-W, spaced to cover the single phase areas as well as a part of the adjacent two-phase field, were prepared as uacuum-melted alloys. Tensile tests at room temperature and stress rupture tests at 1200° and 1500°F we.ve run for time periods to give fracture in 0.1 to 500 hr. Observations mere made of solid-solution and second-phase strengthening or uleakening, coupled with studies of ductility and the role of structure on the noted behavior patterns. THE development of stable creep-resistant alloys while broad and systematic is also highly empirical. A number of simple rules have been suggestedL-" but these are based on scant data. Whereas rules for low-temperature alloy strengthening can be applied with some success in more simple systems, the extension to behavior at high temperatures (greater than about 0.4 of the absolute melting temperature) is very poorly understood and has encountered important exceptions and deviations in terms of atom size or valency effects. In particular, the occurrence of both solid-solution weakening4,5 and second-phase weakening2 at high temperatures is of interest. MATERIALS AND PROCEDURE Nickel was chosen as the base material because of its important role in current high-temperature alloy applications, because of its freedom from a phase transformation, and because of wide solubilities for many elements of interest. The selected alloys were single- and two-phase structures in the Ni-Cr,6 Ni-Mo,7 and Ni-w 8 systems. The alloys were vacuum melted and cast, utilizing high-purity raw materials, in the form of 15 lb ingots. They were readily forged into 1/2-in. bar stock (except the two highest chromium alloys). The alloy compositions are shown in Table I. Typical impurity values are: Carbon: Max 0.03 pct (except for 30 and 35 pct Cr alloys which had 0.07) Nitrogen: Max 0.005 pct (except for two of the Cr alloys which had 0.05) Sulfur: Max 0.004 pct Silicon: Max 0.05 pct Each alloy was solution treated (air quenched) to produce comparable grain size. The two-phase alloys were then overaged in an effort to produce a stable structure for testing at 1200° and 1500°F, The results are summarized in Table 11. Following the heat treatments outlined in Table 11, the bars were machined to a gage section of 1.25-in. long by 0.250-in. diam. In addition to room-temperature tensile tests, stress-rupture tests were run at 1200" and 1500°F for time periods from 0.1 to about 500 hr. RESULTS Room-Temperature Mechanical Properties—The ultimate tensile strength, total elongation, and reduction of area values for all the alloys are plotted vs atomic percent of the solute element in Fig. 1. It can be seen that for the same amount of solute element the ultimate tensile strength increases in the order chromium, molybdenum, tungsten. Elongation increases (reduction of area decreases) with increasing amounts of solute for all the solid solution alloys, the values ranging from 50 to 70 pct. The ultimate tensile strength values for the two-

Jan 1, 1961

By Louis A. Panek

Ground movements in the zone adjoining an active cave were measured at four sites in the San Manuel Mine. Measurements were made to detect extension and inclination, basic components of displacement, which can readily be duplicated by mine personnel using relatively simple equipment. The displacements demonstrated the development of a zone of strain relief surrounding the active cave, within which the ground tends to migrate toward the cave, and extension cracks develop tangential to the cave. This expansion of the ground surrounding an active cave can be exploited to promote future caving; it also creates special problems with respect to the design of an effective ground support system for mine openings in the production area.

Jan 1, 1981

By L. O. Howard

THE CHAIRMAN (WALTER DOUGLAS, New York, N. Y.).--I presume, gentlemen, that Mr. Howard's experience with the Great Falls basic-lined converter has been as regards the tonnage produced from a single lining, perhaps, a world's record. About 6 months ago Mr. Howard shut down and tore out what was left of the first basic-lining which was installed at the Old Dominion, the lining having produced something over 70,000,000 lb. of copper. This was due probably not only to the very excellent grade of the matte which was produced by the smelter there,

Jan 12, 1916

By A. B. Kinzel

A PREVIOUS study1 of the relations of impact strength to inclusions showed that the dynamic strength of steel is lowered by the presence of visible counted inclusions, but that other factors comprised in the term "body" have a marked influence. The previous work was carried out on selected steels from a single source, so that the body factor was purposely minimized, but even under these conditions it was found that inclusion counting or the use of the commercial inclusion rating is not satisfactory. The tensile-impact test, however, was indicated as a satisfactory measure of dynamic strength. It was further suggested that the tensile-impact test should be so standardized as to be suitable for use in specifications, and that the hardness factor should be worked out over a sufficient range to admit ready commercial use of the tensile-impact test. In accordance with these suggestions, and in view of the fact that the steels reported in the previous paper were selected and treated so as to have a minimum variation in body, hardness and structure, further work has been performed on a variety of steels which are not limited by these conditions. The word "body" is used here for want of a better term. It is simply a convenient expression which comprises the effect of the various unknown factors that modify the dynamic strength of the steel. Thus at our present state of knowledge, the writers have chosen to consider hardness, structure and counted inclusion content as factors not comprised in the term "body," and such factors as raw materials, process of melting, fabricating, etc. as comprised in the term "body." Numerous grades of steels made in several ways have been taken from different sources and have been heat-treated to varying hardness by normalizing and by quenching and drawing. The results, therefore, may be considered to be generally applicable to current engineering steels. A certain limitation with respect to the hardness at which steel should be

Jan 1, 1931

By Walter Herd

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

Jan 1, 1930

By Walter Herd

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

Jan 1, 1929

By R. D. Parker

LARGEST of any hoist installation ever manufactured in Canada is that being erected at No. 5 shaft, Creighton mine, of the Inter- national Nickel Company of Canada, Limited. It is a bicylindrical conical- drum hoist with the drums arranged in tandem, and driven by two direct- current motors through single reduction gearing. This hoist was designed by the Canadian Allis-Chalmers, Limited and manufactured at their works in Lachine, Quebec.

Jan 1, 1936

By Frank F. Aplan

INTRODUCTION Coal is a solid, combustible mineral substance resulting from the degradation and alteration of vegetable matter largely in the absence of air. In this natural process of coalification, some non-combustible mineral matter is always associated with the combustible material. Coal preparation or cleaning is the process of removing this inert mineral matter from the coal. Preparation is highly successful in removing the large fragments of inert material, but is not very effective in removing the fine inorganic mineral matter intimately associated with the coal. Of the 600 million tons of coal produced in the United States every year, approximately one-half is produced by coal cleaning methods (1). The bulk of this tonnage is cleaned by coarse or intermediate gravity preparation methods (5 inches to 28 mesh, Tyler). Fine cleaning, say, -28 mesh, is done by shaking tables, washing cyclones, and flotation, or, until recently, the fines were either incorporated into the clean coal or simply discarded--not infrequently, the latter. In 1972, only 13 million tons of raw coal were cleaned by flotation in the United States, and from this 8.4 million tons of clean coal were produced (1). The percentage of clean coal produced by flotation in Europe (England, West Germany, Poland, U.S.S.R., etc.) is substantially higher. However, coal flotation has grown rapidly in the United States from only a few plants in 1950 to 31 in 1960 (2) and 66 in 1970 (1). Virtually all new preparation plants incorporate flotation into their basic flowsheet. The essential difference between ore and coal flotation is that for ores the entire tonnage is ground to flotation size, whereas for coal

Jan 1, 1976

By R. G. Lazzell

THE British are worried about the postwar possibilities of their coal mining industry. Indeed, there are causes for this worry, with the aver- age 1943 cost of production at about $5.40 per long ton, compared to $3.20 in 1938. Average production per man day has dropped from 1.12 in 1938 to 1.03 long tons in 1943. As a comparison, production per man day in the United States is approximately 5 long tons. The average day wage in the British mines is now a little aver $4; in 1938 the average day wage was about $2.25. Great Britain produced 227 million long tons in 1938 from their deep mines, and in 1943 production was 194.5 million, with an additional 4.5 million from strip mines. To meet present wartime needs, output is being supplemented by the production of strip- mined coal, an industry that did not exist prior to the war. Strip mining is now producing at the rate of 15 million long tons per year.

Jan 1, 1944

By E. P. Klier, Volker Weiss, George Sachs

IT has been shown that the isothermal transformation of austenite in a special steel can be modified by isothermal holding in the high subcritical transformation range.' Since this treatment potentially leads to increased hardenability, limited testing has been completed to determine if the stabilization effects observed with this treatment can be used to advantage in the heat-treating of 4340 steel. As an index of the effects of the several austenitizing treatments on the hardenability of the steel, Jominy-type hardenability tests were completed for specimens 2.5 in. in diameter and 8 in. long. Since the steel studied is to be used at strength levels where notch sensitivity is of major concern, notch sensitivity after selected austenitizing treatments has been evaluated by notch tensile tests for several specimen sizes. The steel composition and the austenitizing treatments are given in Table I. The test specimens are presented in Fig. 1. The hardenability data are given in Fig. 2 and the notch tensile properties are presented in Fig. 3. The hardenability of the steel investigated when determined by use of the standard Jominy test specimen2 as high and remained essentially unchanged for the different austenitizing treatments. For the larger test specimen, as has been shown by other investigations," the characteristic hardenability indexes are changed and it becomes possible to isolate austenitizing treatments which promote maximum hardenability. The stepped austenitizing treatment promotes higher hardenability as is indicated in Fig. 2. The evaluation of notch sensitivity for very high strength steels is best accomplished by means of the notch tensile test. The experimental conditions of the test, however, modify the notch strengths measured, and in the present experimentation an effort was made to achieve a limiting notch condition by fixing the notch root radius at 0.001 in. while the specimen diameter was allowed to increase from 0.3 to 1.1 in.* For this root radius the notch strength, 0.3-in.-diam specimen, and this trend differs from that for the larger specimens. At the highest tempering temperatures the 1.1-ip.-diam specimens yield comparable results for the austenitizing treatments compared. However, as the tempering temperature is progressively lowered below 800°F, em-

Jan 1, 1958

By L. W. McKeehan

THE occurrence of twins in large ferrite crystals, made by a new process, was reported in a recent note.1 This paper describes a typical case of such twinning and suggests, on the basis of the observed facts, why smooth slip-planes are rarely observed in this metal. METHOD OF PREPARATION The material in. which the crystals here dealt with were grown was made from 1/8-in. Armco iron welding rod containing C, 0.04; S, 0.037; P, 0.003; Si, 0.008, and Mn, 0.02 per cent. This rod was cold drawn into wire about 1 mm. dia. A piece of this wire was supported vertically and was locally heated in hydrogen at atmospheric pressure to about 1400° C. by an alternating current (60 cycles per sec.) of about 35 amp., passed through it between a pair of traveling contacts about 8 cm. apart. The rate of travel for the case in hand was 12 cm. per hr. After some 30 cm. of the length of the wire had been heated and cooled in this manner the whole wire was immersed for a few seconds in dilute nitric acid, not restrained by alcohol. Etching was continued until, ass nearly as could be judged by eye, the original smooth cylindrical surface of the wire was no longer capable of specular reflection. MEASUREMENTS The wire in the etched state was next mounted in a goniometer of special form which allowed the measurement of the spherical coordinates of the normals to any plane surfaces left by the etching. These coordinates were most conveniently a polar distance, ?, from one direction of the wire axis, and an azimuth or longitude, [ø], from an arbitrary prime meridian. The region to be described more particularly is shown at a low magnification in Fig. 1, which gives two different views, differently illuminated to show the spatial relationship of a crystal occupying most. of the part shown and of an inclusion, or rather a series of three inclusions suspected of being twins based on the principal crystal.

Jan 1, 1928

By Blandford C. Burgess

Mica is an orchid among minerals. It is formed in pegmatites, one of the most bizarre of igneous formations, and is exceeded by few other minerals in the perfection it may attain as to size, color, and cleavage. First used for window glazing, as an ornament and article of trade, it has become one of the most essential insulators of electricity, heat, and shock. Most internal combustion engines use mica condensers or capacitors and such machines of war as planes, tanks, and submarines are immobile without it. The original manuscript of this guide was written in April 1943 at the peak of war emergency. It was not used because shortly thereafter a decision was made to buy on a one price basis eliminating differentials for both quality and size. This is now presented with the thought that from the standpoint of preparedness we can only consider another war imminent and every effort should be made to set up in usable form the experience gained during the Second Morld War. Colonial Mica Corp. was set up by Metals Reserve Co. as a wholly owned government agency to encourage production of domestic mica and to purchase it. It soon became the exclusive buyimg agency for such mica. The writer as Southern Manager called on all the private agencies buying mica to assist in formulating buying policies, methods, and prices. A meeting was held for that purpose in Asheville, N. C., July 20, 1942. In the general discussion the first two hours of the meeting it was decided that the following factors should be considered in pricing strategic mica: clearness, flatness, trimming, color, classification (size and quality), free splitting, hardness, and air inclusions. Most of the mica miners have been buying strategic mica, according to the mine, as No. 1, No. 2, or Nos. 1 and 2 combined. In addition to these grades of strategic mica they have been buying three lower grades of mica, electric (vegetable-stained), black-spotted and black-stained. A number of mines were named one by one and the buyers present gave their opinions as to the basis they would use in buying the sheet mica from each. It was suggested that in addition to the prices already published, prices be posted up to 10 pct higher for special quality and preparation and prices be posted 25 pct lower than the published prices for the lowest acceptable grades of strategic mica, giving the buyers authority to make intermediate prices according to the quality and preparation. It was thought desirable at the same time to announce prices for nonstra-tegic mica where such quality is being obtained in mines producing strategic mica and where it would be necessary to take the output in order to get the strategic mica. It was also suggested that the price of electric and black-spotted mica be 50 pct below the price of the lowest grade of strategic mica and the price of black-stained mica be 60 pct below the price of lowest grade strategic mica. The few experienced buyers available were employed but they were inadequate for the job and others had to be trained. All needed a guide or primer of some kind to attain systematic procedure and consistent prices in their respective buying areas. The Mica Buyers Guide was formulated for that purpose based on experience gained in the first six months of buying. The Preface to the original guide was as follows: The purpose of this guide is to serve as a text in training beginners and as a handbook for experienced buyers of the instructions which have been issued up to this time. At the meeting of prospective buyers last summer, it developed that the first essential to attain uniformity must be some kind of check sheet. Our "Mica Buyers Report" was developed for this purpose and forms the backbone of this guide. Price is determined according to size, quality and preparation. Size can be measured, but no system of measurement or machine has been devised which can be substituted for the trained eye of the buyer to deterrnine quality and preparation. Although the "One Price" system was instituted and the "Guide" not used, the buyers were required to continue making out a "Mica Buyers Report" (Fig1) with each lot of mica purchased. The form proved its value and there is no doubt that in another such emergency some similar form should be

Jan 1, 1950

By I. S. Servi, N. W. Marr

TIN markedly increases the softening temperature of pure copper with only a moderate effect on conductivity. Smart and smith' indicated a substantial increase in softening temperature upon addition of different levels of tin up to 0.05 pct in oxygen-free copper. However, after finding no effect of tin in copper containing about 0.025 pct O, they concluded that "the presence of oxygen completely nullifies these changes in properties by precipitation of SnO2.'' Since preliminary tests on Cu-Sn-0 alloys indicated that this conclusion is not valid outside the extremely limited tin range investigated by Smart and Smith, research was primarily directed toward the partition of tin between the copper-base matrix and the oxide phases. Experimental. Material was prepared by sealing an 80 to 100-g charge consisting of oxygen-free copper, tin, and copper oxide into a y-in.-ID quartz capsule which was evacuated and back-filled with tank-grade argon to 3 atm. The sealed vials were heated to 1125ºC, kept at temperature for 30 min, occasionally agitated, and then allowed to air-cool outside the furnace ("as-cast"). The castings were cold-swaged to 0.370 in., annealed 1 hr at 600°C ("as-annealed"), and cold-swaged 16.5 pct ("as-swaged"). Cross sectional wafers were annealed for 1 hr at various temperatures and Rockwell F hardness measured. The "softening temperature" was defined as the interpolated temperature at which the hardness was 50 Rockwell F. Electrical resistance was measured by an ac poten-tiometric method on 0.040-in.-diam wires after a 1 hr anneal at 600°C. Relative accuracy was of the order of 1 pct. Chemical analyses for tin were performed by two methods, identified as "Acid flux" and "HN03 dissolution". The first consisted of fusing the sample with potassium pyrosulfate and leaching the resulting melt with 10 pct sulfuric acid. The spectrophotometric procedure which followed is described in Ref. 2. Oxygen analyses were performed by the vacuum-fusion method with a bath temperature of 1650°C. Tin content of oxides and copper phases was measured with the X-ray microprobe, using a calibration curve based on a series of oxygen-free Cu-Sn alloys. Results. In Fig. 1, the nominal tin composition for alloys containing nominally 400 ppm O was plotted vs the analyzed or the computed tin content—the latter derived from one of the following: 1) "acid flux" chemical analysis; 2) "HN03 dissolution" chemical analysis; 3) X-ray microprobe analysis of the copper matrix; 4) equivalent tin content, based on the measured increase in electrical resistivity (an increase in resistivity of 1.6 microhm-cm is approximately equivalent to 1 wt pct of sn1,3). It is evident from Fig. 1 that the results of the acid flux analysis are consistent with the nominal composition while the HNO3 dissolution method generally yields lower values, consistent with those obtained from electrical resistivity measurements and somewhat higher than those obtained by microprobe analysis. Microprobe and resistivity values are affected only by the tin in solid solution; hence the HN03 method

Jan 1, 1970

By H. F. Winham

THE history, development, subsurface geology, production, economics and estimated reserves are discussed in this paper. The Magnolia structure is an anticline with a known maximum structural relief at 372 ft., and the areal extent of the producing acreage is 4494 acres. Production is obtained from the Smackover oölitic lime and 116 successful wells have been drilled. The field, which was developed on 4o-acre spacing, has been under strict control. It is believed to be producing with a strong water drive. To date it has produced more than eighteen million barrels and the estimate of ultimate recovery is 220 million barrels. EARLY HISTORY The Magnolia field is in Columbia County, Arkansas, T. 17 S., R. 19 and 20 W. Various geologists had long been interested in this general area, and as early as 1921, John F. Magale was able to define a surface structure. The first wildcat, one of the first in Columbia County, was drilled in 1923 by Mid-States Oil Co., in sec. 10, T. 17 S., R. 20 W. This well was about 1 ½ miles northwest of the Kerlyn Oil Company's discovery well and was based on surface geological work done by jewel and Dobie. Subsequently, several shallow wells that were not carried below the Upper Cretaceous beds were drilled in the immediate area of the discovery well, but none of them contained any commercial showings of oil or gas. In the latter part of 1935, Elam and Magale (or Southwood) Garrett No. I was located in sec. 13, T. 17 S., R. 20 W., ¾ mile east of the discovery well. It was drilled to a total depth of 4018 ft. in the lowermost Glen Rose beds but failed to obtain any showings of oil or gas. Interest had been stimulated in this general area, however, by the discovery of several oil fields, mainly Glen Rose oil production in the Rodessa field in Louisiana in 1935, Smackover lime production in Snow Hill in May 1936, production from the Cotton Valley formation in Schuler in 1037, and Smackover lime production from the Buckner field in November 1937. With this background and subsequent seismic work, which was carried on partly because the old shallow wells drilled in the township had shown evidence of closure in the Upper Cretaceous beds, the discovery well, Kerlyn Oil Company's Barnett No. I, sec. 14, T. 17 S., R. 20 W., was originally projected to a total depth of 6300 ft., to test the equivalents of the Morgan sands of the Cotton Valley series, then producing at Schuler. The well was carried to a total depth of 6325 ft. and tested the objective beds without finding commercial production. In the meantime, however, one well had found production in the Jones sand and another in the Smackover lime at Schuler. Kerlyn immediately made arrangements to deepen the Barnett well to the Smackover lime. The top of the Smackover lime was encountered at 7618 ft. and the well was cored and drilled to a depth of 7740 ft.

Jan 1, 1942

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, also Assoc. Mem. Am. Soc. of C. E.; excellent technical education, and best of references covering 12 years in responsible charge of work; experienced in surveys, construction, prospecting, mine

Jan 12, 1917