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NAME AND OBJECT SEC. 1. This Institute is incorporated under the Membership Corporations law of the State of New York; its corporate name is American Institute of Mining and Metallurgical Engineers, Inc.; and its abbreviated title A. I. M. E. SEC. 2. The objects of this Institute, as set forth in its certificate of incorporation, are: "To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members the information thus obtained, and to establish and maintain a place for meeting of its members, and a hall for the reading of papers and delivery of addresses, and a library of books relating to subjects cognate to the sciences and arts of mining and metallurgy."

Jan 1, 1923

By B. M. Larsen

IN spite of the great amount of operating experience and of studies directed toward elucidation of the interrelation of the several processes going on in the blast furnace, the present picture of its operation is based largely on indirect evidence and on speculation. The reason for this unsatisfactory situation is the extreme difficulty of making direct observations and significant measurements while the furnace is operating, and of translating laboratory experience to the conditions obtaining in the smelting process. Yet there are questions that can be investigated with some promise of a definitive answer; and it is the purpose of the present paper to set forth some of these questions, as a basis for discussion, which may, it is hoped, lead to active work on some of them. In order to provide a starting point for this discussion, some views held tentatively by the writer are outlined, along with a certain amount of evidence gathered from operating records and interpreted on the basis of the ideas expressed. These opinions may prove not to be pertinent, and may well not be in accord with the opinions of others; they have been included to encourage others to do likewise and on purpose to provoke informal discussion. In this way it should be possible to transcend the limitations of formal papers; to bring forth suggestions of new hypotheses or new methods of investigation; and to promote better understanding between investigators and operators in this difficult field. The statements made express the present views of one physical chemist who is not too familiar with all the difficulties of maintaining these enormous reaction vessels in reasonably smooth and economical operation; who, however, is persuaded that some of these difficulties would be less formidable if surer knowledge of the several interrelated and concurrent processes were available and made use of. For these difficulties arise largely, it is believed, from variation in conditions which the operator must meet as best be can, and should lessen as these conditions can be brought under control so that they are either made substantially constant or the variations are neutralized by compensating methods. A. VARIATION IN BURDEN AND IN MIXING OF CHARGE To the scientific investigator, who aims to control the conditions of experiment and to limit the number of variable factors, the most perplexing aspect of the blast-furnace process is that nothing seems to remain constant for long. Variations of burden seem to be unnecessarily frequent; and, even if the charge were constant from hour to hour, its constituents usually are not mixed as intimately as they might well be. It is understandable that separate layers of coke and of ore, also separate layers according to size, promote permeability and the

Jan 1, 1947

By T. Sterry Hunt

THE deposit of rock-salt which is known to exist along the eastern shore of Lake Huron, in the province of Ontario, has lately been more completely explored than before, by a boring with a diamond drill, put down by Henry Attrill, Esq., of New York City, and the results obtained are so important in every way that I make no apology for presenting them to the Institute of Mining Engineers. I may be permitted to preface an account of this remarkable exploration, and of its results, with a historical sketch of the discovery and development of this salt-region. It was in December, 1865, that a boring was begun near the town of Goderich, in the hope of finding petroleum. In this the adventurers were disappointed, but, after passing through about 800 feet of limestone, they encountered a series of variegated marls, in which, at a, depth of 964 feet from the surface, a bed of rock-salt, 30 feet in thickness, was met with in May, 1866. The boring was carried to a depth of 1010 feet, ending in hard rock, and yielded, by pumping, a very pure saturated brine when examined by me in August of the same year. In the report of the Geological Survey of Canada for 1863-66, published early in 1867, I described this salt-well, with many geological details, and gave an analysis of the brine. In the next three years a considerable number of wells was sunk in and around Goderich, and numerous trials were made in various other parts of the region. Salt was found at Kincardine, thirty miles north-northeast from Goderich, at a depth of about 900 feet, and also at Clinton, thirteen miles southeast, at 1180 feet. Records of these wells, with analyses of the brine from them, were given by myself in a subsequent report of the Geological Survey, 1866-69, published in 1870 (pp. 211-244), together with accounts of various unsuccessful borings in the neighborhood, analyses of the brines from the various wells (including one analysis by Dr. Goessmann), with many details of the salt-manufacture at Goderich, at Syracuse, New York, and at Saginaw, Michigan. The geological character of the region was there discussed at length, and it was shown that the salt here occurs in the Onondaga or Salina formation, which

Jan 1, 1877

By Shiou-Chuan Sun, R. F. Wesner, J. D. Morgan

0. C. Ralston and F. Fraas—Dr. Sun and associates have presented an interesting paper not all of which is comprehended by us. The data assembled measure the deflections of particles in an electrostatic field as a function of a number of independent variables and some dependent variables that are not sharply differentiated. These data are all based on a Johnson type machine of definite, well-described geometry, something not often done in electrostatic separation literature. One new fact brought out by this technique is the effect of coal dust on admixed pyrite and quartz. The effects are opposite in character, as should be expected and we do not agree with the authors that these effects are negligible. Fraas' also used a multiple cell "distribution analyzer" and gives in fig. 5 of his paper a straight line plot with no humps or curves. This is not necessarily at variance with Sun's results because Fraas used a larger gap between electrodes and had no evidence of particles adhering to or dropping off the charged electrode. The section of Sun's paper on effect of surface conductivity contains a speculation that the dielectric constant "represents more or less the electrical conductance of the bulk body instead of the surface of the mineral particles." A simple picture of the meaning of the dielectric constant is that it is the specific inductive capacity of a dielectric when used as the dielectric between the plates of a condenser. It is at once evident that the above speculation confuses capacity with conductance—two definitely independent variables. We ask the authors to state in what group or subdivision their garnet belongs; what method and units were used in calculating the data of col. A, table I and their meaning; what was the temperature of the carrier roll and, finally, has any effort been made to investigate the effects of particle shape on distribution in the electrostatic field? S. B. Hudson—I have read this article with great interest. We have been engaged in research work on the principles of electrostatic separation in this laboratory for some time now, and our findings agree with those of the authors in many respects. The article shows evidence of careful and valuable research in the field of electrostatic separation. A "distribution analyser," very similar to that described in an earlier article by one of the authors," was incorporated in an inclined plate-type electrostatic separator designed and built in the Melbourne University laboratory in 1948 for investigation purposes.22 The actual splitting edges were machined from y! in. per-spex, and the paper hoppers were supported on linen thread immediately below the perspex dividers. These dividers fitted into machined slots in a framework to give accurate Yz-in. spacings. The hoppers (staggered) fed directly into a rack of test tubes, which is supported on a vertical pantograph arrangement. The rack was positioned with guides on the horizontal pantograph stand, and this ensured positive alignment when replacing the rack after making weighings. In later work, when much heavier feed rates were used, of the order of 30 to 40 Ib per in. per hr a rack fitted with rectangular metal containers and similarly aligned was used. Some work was done here on comparing the distributions of minerals when passed separately and when passed as a mixture, and it was found that there was quite an appreciable difference in the two results.= However, in our separator the particles do not pass down the plate in a single layer, and this difference is probably caused by collisions of one mineral particles with the other mineral particles. In most of the investigational work here, the change of the center point of the distribution is measured to establish the effect of a variable, such as voltage. Two minerals (zircon and rutile) have been studied rather exhaustively, and it was found that their distributions are very nearly normal. Owing to the sharpness of the distribution curves, the usual method of obtaining the mean or median was inaccurate, and was not used; instead the mean (also the median), calculated on the assumption of a normal distribution, was used to locate the center point of each distribution and proved satisfactory. The effect of polarity becomes very apparent in the plate-type separator where frictional charges play a very important part when using highly resistive minerals such as zircon. With rutile, a comparatively conductive mineral, polarity of the electrode has little effect. On the other hand, the magnitude of the voltage has a far greater effect on conductive than on resistive minerals. Shiou-Chuan Sun (authors' reply)—Thanks are extended to Drs. Ralston and Fraas for their keen interest in this paper. Their questions concerning coal dust,

Jan 1, 1951

By Shiou-Chuan Sun, R. F. Wesner, J. D. Morgan

0. C. Ralston and F. Fraas—Dr. Sun and associates have presented an interesting paper not all of which is comprehended by us. The data assembled measure the deflections of particles in an electrostatic field as a function of a number of independent variables and some dependent variables that are not sharply differentiated. These data are all based on a Johnson type machine of definite, well-described geometry, something not often done in electrostatic separation literature. One new fact brought out by this technique is the effect of coal dust on admixed pyrite and quartz. The effects are opposite in character, as should be expected and we do not agree with the authors that these effects are negligible. Fraas' also used a multiple cell "distribution analyzer" and gives in fig. 5 of his paper a straight line plot with no humps or curves. This is not necessarily at variance with Sun's results because Fraas used a larger gap between electrodes and had no evidence of particles adhering to or dropping off the charged electrode. The section of Sun's paper on effect of surface conductivity contains a speculation that the dielectric constant "represents more or less the electrical conductance of the bulk body instead of the surface of the mineral particles." A simple picture of the meaning of the dielectric constant is that it is the specific inductive capacity of a dielectric when used as the dielectric between the plates of a condenser. It is at once evident that the above speculation confuses capacity with conductance—two definitely independent variables. We ask the authors to state in what group or subdivision their garnet belongs; what method and units were used in calculating the data of col. A, table I and their meaning; what was the temperature of the carrier roll and, finally, has any effort been made to investigate the effects of particle shape on distribution in the electrostatic field? S. B. Hudson—I have read this article with great interest. We have been engaged in research work on the principles of electrostatic separation in this laboratory for some time now, and our findings agree with those of the authors in many respects. The article shows evidence of careful and valuable research in the field of electrostatic separation. A "distribution analyser," very similar to that described in an earlier article by one of the authors," was incorporated in an inclined plate-type electrostatic separator designed and built in the Melbourne University laboratory in 1948 for investigation purposes.22 The actual splitting edges were machined from y! in. per-spex, and the paper hoppers were supported on linen thread immediately below the perspex dividers. These dividers fitted into machined slots in a framework to give accurate Yz-in. spacings. The hoppers (staggered) fed directly into a rack of test tubes, which is supported on a vertical pantograph arrangement. The rack was positioned with guides on the horizontal pantograph stand, and this ensured positive alignment when replacing the rack after making weighings. In later work, when much heavier feed rates were used, of the order of 30 to 40 Ib per in. per hr a rack fitted with rectangular metal containers and similarly aligned was used. Some work was done here on comparing the distributions of minerals when passed separately and when passed as a mixture, and it was found that there was quite an appreciable difference in the two results.= However, in our separator the particles do not pass down the plate in a single layer, and this difference is probably caused by collisions of one mineral particles with the other mineral particles. In most of the investigational work here, the change of the center point of the distribution is measured to establish the effect of a variable, such as voltage. Two minerals (zircon and rutile) have been studied rather exhaustively, and it was found that their distributions are very nearly normal. Owing to the sharpness of the distribution curves, the usual method of obtaining the mean or median was inaccurate, and was not used; instead the mean (also the median), calculated on the assumption of a normal distribution, was used to locate the center point of each distribution and proved satisfactory. The effect of polarity becomes very apparent in the plate-type separator where frictional charges play a very important part when using highly resistive minerals such as zircon. With rutile, a comparatively conductive mineral, polarity of the electrode has little effect. On the other hand, the magnitude of the voltage has a far greater effect on conductive than on resistive minerals. Shiou-Chuan Sun (authors' reply)—Thanks are extended to Drs. Ralston and Fraas for their keen interest in this paper. Their questions concerning coal dust,

Jan 1, 1951

By W. E. Bonini, E. A. Hickok

IN the course of an investigation directed toward expanding ground-water facilities in Essex and Morris counties, New Jersey, the Board of Water Commissioners of the city of East Orange authorized a seismic-refraction survey' for the purpose of de-lineating bedrock topography below unconsolidated overburden. Results of the survey were highly satisfactory and led to the preparation of a comparatively detailed bedrock contour map. Knowledge of the bedrock depth and configuration was an important aid in selection of sites for test drilling. The portion of the East Orange Water Reserve under consideration is in the flood plain of the Pas-saic River about 10 miles west of Newark, N. J. The flood plain is about 175 ft above mean sea level and is bordered by low hills rising to elevations of approximately 250 ft. The bedrock underlying the Water Reserve consists of sandstone and shale of the Triassic Brunswick formation and is covered everywhere by deposits of unconsolidated glacial outwash sand and gravel, lacustrine clay, and recent river silt as much as 150 ft thick. Yield of wells in the sandstone and shale averages 100 to 200 gpm. Since production wells constructed in the sand and gravel aquifer in the buried river valley shown on the contour map (Fig. 1) yield 300 to 1400 gpm, it was proposed to locate additional production wells in this buried valley, where the yields per well would be maximum. In 1939 and 1946 the East Orange Water Dept. had electrical-resistivity surveys made to determine depths to bedrock. From the resistivity data the exploration company prepared a bedrock contour map. A well field expansion program begun in 1955 utilized this information to locate sites for test wells along a predicted northward extension of the buried valley in which existing production wells are located. After several test wells (wells 201-205) had been drilled, it became apparent that the resistivity information was unreliable." For example, test well 201 recorded bedrock at a depth of 72 ft, whereas the resistivity depth determination was 130 ft. As a consequence, the test drilling program was temporarily suspended and a seismic survey was under- taken to determine the topography and extent of the buried valley known from well records to underlie the existing well field. In the first phase of this study, several seismic shot point locations were placed at sites where well logs had been obtained previously. This procedure is necessary in a new area to determine whether the seismic method is applicable and what degree of accuracy is to be expected. At the East Orange Water Reserve, depths obtained from the shot points near test wells 202, 203, and 204 were within 8 to 11 pct of the depths logged (Table I). With this assurance that accurate results could be obtained, additional seismic spreads were located on the Water Reserve. Using a portable refraction seismograph, in the fall of 1955 a crew of four men shot a total of 29 reversed seismic spreads in a period equivalent to six field days. Charges as heavy as 3 1b of 40 pct dynamite were necessary at a few places to overcome ground vibrations caused by traffic on nearby highways. At most other sites, a 1-1b charge was sufficient. Travel-time plots were made for all spreads, and depths and true velocities were calculated according to formulas for multiple sloping layers by Ewing, Woollard, and Vine.' The plot of spread 7 (Fig. 2) is typical of the short spreads in which bedrock was shallow—about 50 ft in this case. Where there were not enough arrivals through the bedrock to define the high velocity bedrock line, the spreads were lengthened. This was done by placing shots on line several hundred feet away from each end of the line of geophones. It was then possible to construct complete reverse plots for both short and extended shot points (see spread 27, Fig. 3). Four individual depths were calculated from each extended spread. Three and in some cases four seismic layers were observed. The surficial layer had a velocity range of 900 to 1200 fps, the lowest velocity recorded. This seismic layer is above the water table and is interpreted as recent river silt. The bedrock had the highest velocities, which ranged from 10,600 to 16,400 fps. Intermediate velocities ranged from 4500 to 6800 fps. In every case the intermediate layer was within

Jan 1, 1959

By AIME AIME

MORE than thirty members of the Coal Division attended the Coal Land Valuations Round Table on Monday morning. Chairman Dilworth stated that the Committee had been appointed to take up the question and, after reading the list of members of the Committee, pointed out that the object of the meeting was to formulate a plan of action rather than to discuss any phases of valuation, per se. To this end he presented a tentative outline of points to be considered in the future by the Committee. After a lively discussion on the desirability of inclusion of some questions in the agenda of the Committee, the following outline was adopted :

Jan 1, 1931

SEC. 1. This Institute is incorporated under the Membership Corporations law of the State of New York; its corporate name is American Institute of Mining and Metallurgical Engineers, Inc.; and its abbreviated title A. I. M. E. SEC. 2. The objects of this Institute, as set forth in its certificate of incorporation, are: "To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members the information the obtained, and to establish and maintain a place for meeting of its members, and a hall for the reading of papers and delivery of address, and a library of books relating to subjects cognate to the sciences and arts of mining and metallurgy."

Jan 1, 1943

F. McMillan Stanton was born in New York City on May 23, 1865, the son of an English father and of a mother whose family was linked with that of Peter Stuyvesant. Mr. Stanton took his degree from the School of Mines of Columbia University in 1887, worked for two years as an assayer and surveyor and then went into the mining field on his own account. After a few years, he was offered a position with the Atlantic Mining Co., and began the work which was to continue with marked success for twenty-three years. In 1910, Mr. Stanton retired and went to Europe for a rest. Upon his return in 1914, he was elected treasurer and director of the Mohawk Mining Co., the Wolverine Copper Mining Co. and the Michigan Copper Mining Co., to which group was later added the White Pine Extension, Copper Co., and continued to serve these companies until the time of his death, Sept. 12, 1916.

Jan 12, 1916

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained.

Jan 1, 1923

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained.

Jan 1, 1923

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained.

Jan 1, 1917

By J. B. Cohen

EARLY investigators1-4 reported that additions of beryllium to silver caused embrittlement. The in-termetallic phases which are now known to exist5,' were not known at the time. Solidification appeared to occur by a simple eutectic reation.4,7 (The primary beryllium-rich phase appeared globular, when the liquidus temperature was near the melting point of pure beryllium, and angular when the liquidus was much lower; in discussion of Sloman's work,4 it was suggested that this difference was due to an intermetallic compound which was not revealed by the polishing technique.) In the investigation reported here, it was found that if the compounds now known to exist were avoided, certain beryllium-silver alloys containing large amounts of the primary beryllium phase possessed sufficient ductility to be cold formed. Alloys containing 14 and 20 at. pct Ag were prepared from vacuum-cast beryllium containing 1.0 to 1.2 pct impurities and silver, 99.99+ pct pure. The elements were melted together by induction in beryllia or alumina crucibles under argon at less than 1 atm pressure. The cooling rate was adjusted by regulating the temperature of the melt and by reducing the power to zero without stopping the water flow in the induction coils, which were in contact with the crucible. Ingots were about 0.75 in. in diam with a grain size of 0.12 to 0.25 in. Microscopic investigation of transverse or longitudinal sections of an ingot cast from a temperature well above its melting point showed that, in general, the compounds did not form, presumably because of rapid cooling; the alloys consisted of beryllium-rich particles in a silver-rich matrix as shown in Fig. 1. A eutectic structure was not observed, probably .due to the low beryllium concentration of the eutectic composition and eutectic divorcement. Within a given grain, the small globules of the primary phase were all oriented in the same direction, as indicated by examination under polarized light; the orientation varied from grain to grain. This suggested that the globules were branches of the same dendrites. If cooling was too slow, a third constituent was observed in the microstructure; because it formed around the primary beryllium-rich globules it was Fig. 1—Ag-Be alloy, 18.6 at. pct Ag, as-cast. Bright field illumination. Etched with an aqueous solution of NH,OH and H2O2. X500. Reduced approximately 21 pct for reproduction. probably the 6 compound. A thin ring around an ingot often contained this constituent. When this compound was present in large quantities, or the silver segregated so that large regions occurred with the beryllium-rich globules in contact, sections from the ingot were brittle. When the compound was initially absent, it was possible to carry out reductions in thickness of 50 pct by cold rolling with only limited edge cracking; failure did not occur until reductions of 80 pct. A typical cross section after cold rolling is shown in Fig. 2. After simple bend tests, microcracks were found; these apparently were difficult to propagate in the two-phase structure, as the specimens continued to behave in a ductile manner after the cracks appeared. Similar cracks would probably be closed during rolling. It is apparent in Fig. 2 however, that the primary beryllium particles undergo extensive plastic deformation. Hardness values of the alloys indicated that some work-hardening occurred during cold working. Fig. 2—Ag-Be alloy, 18.6 at. pct Ag, reduced 83 pct in thickness by cold rolling. Bright field illumination. Etched with an aqueous solution of NH,OH and H2O2. X500. Reduced approximately 21 pct for reproduction.

Jan 1, 1961

By L. P. Davidson

THE new electrolytic zinc plant of the American Zinc Company of Illinois commenced operation in April 1941. The simple flowsheet using the standard current density and the economic reasons that dictated it are given herewith. The Evans-Wallower Zinc Co. built an electrolytic zinc plant at Monsanto, Ill., in 1929 and .operated it for about two years. The plant stood idle from 1932 and was purchased by the American Zinc Co. in 1940. Because of the condition of the equipment, excepting the motor generator set, a complete rebuilding was necessary. The Fairmont City plant of the American Zinc Co. could treat the leach residues, the purification cake and the skimmings from the melting furnace in its various plants. This possibility permitted a simple flowsheet with good economic results. The flowsheet is shown in Fig. I. The calcined concentrates are leached in mechanically agitated tanks with spent electrolyte and such ferric iron solution as necessary. When the acid has been neutralized and the iron coagulated, the fluid is discharged to settling tanks. The underflow from these thickeners is filtered on a Moore filter; the filter cake leaves the plant for retreatment and the filtrate joins the thickener overflow. Zinc dust is added to this solution until the copper and cadmium are precipitated. The pulp is filtered through Shriver presses, which deliver the purified solution to storage tanks, and the copper-cadmium-zinc cake is shipped for retreatment and recovery of these three metals. The purified solution is electrolyzed; the regenerated acid is returned for use in the leaching plant and the cathode zinc, after stripping, goes to the melting furnace, from which it is cast in slabs. The skimmings from the melting furnace are shipped to the Fairmont City plant for reduction to metal in. the retort furnaces. The choice of this simple flowsheet was made possible only because of the facilities of the Fairmont City plant. The long leaching period, with high acid content and high temperature which characterize the high-density process, gives a higher zinc extraction but also dissolves more impurities, which must be removed. The same is true to a lesser degree of the multi-step leaching of the western low-density plants. By the sacrifice of some initial extraction, solutions can be obtained that are relatively easy to purify and give good ampere efficiency. This loss in initial extraction is made up in the retreatment of the residues in the Waelz plant. The impurities that accompany the zinc thus extracted are inconsequential when the Waelz product is treated in a distillation plant. It was recognized that this flowsheet would require a somewhat greater amount of sulphuric acid-either as acid or as sulphate sulphur in the calcine-because of poorer washing. The sulphuric acid plant at Fairmont City could deliver 60° Be. acid to compensate for the sulphate loss and the cost would be less than the cost of more intensive washing.

Jan 1, 1942

By J. A. Berger, R. J. Towner

A method for determining the disorientation between sub-grains that .share a common tilt or twist boundary from measurements on X-ray micrographs is described. The method may be applied to subgrains of almost any orientation having boundary angles in the range from about 1 min to 1 deg of arc. An adaption of the Berg-Barretl method has been made to allow calculation of small angles of about 1 min to 1 deg of arc: between adjacent subgrains from the relative displacement of their images on X-ray micrographs. schulz4 gave equations for determining subgrain disorientation where the axis of subgrain rotation and the reflecting crystal planes were parallel to the specimen surface. In our method, however, they need not be parallel and, indeed, may have va:rious orientations. His camera setup, involving a fine-focus X-ray tube for obtaining high resolution with continuous radiation, was different from the one used in the present investigation (a 1.2 x 1.2 mm effective source and characteristic radiation). The X-rays produced a slight magnification in the subgrain images in the Schulz method, but not in the present method. The commonly available type of X-ray tube used permitted relatively short exposure times with a fine-grained photographic plate, which could be magnified optically many times for the examination of small subgrains. The method is illustrated by results obtained on {110} tilt boundaries in a polygonized aluminum single crystal of 99.994 pct purity. The flat crystal was stretched 6 pct in tension and then heated at 500°C for a cumulative time of 5 hr. Earlier, cahn5 studied subgrains formed by polygonization in stretched and heated aluminum crystals. He observed kink bands to have well defined boundaries lying in (110) planes, at least in the early stages of deformation. Cahn found that the (110) tilt boundaries formed by polygonization were directly related to the lattice bending about the <211> axis which lay in the (111) slip plane perpendicular to the <110> slip direction. DESCRIPTION OF THE CAMERA Our camera was similar in detail to Honey-combe&apos;s.6 Unfiltered copper radiation was used at 35 kv, and 20 ma. With the particular specimen used here to illustrate the method, a 1.2 by 1.2 mm effective source and a distance of 780 mm from target to specimen were employed, giving a convergence of 5 min of arc in the primary beam. The distance was 9.5 mm from the specimen to film. The upper 1/2- by 1-in. portion of the front surface of the specimen was irradiated with the film in parallel position. Since the specimen had been inhomogeneously deformed, many regions were in a position to reflect characteristic radiation at the Bragg Angle. Five minute exposures were satisfactory with Kodak Single Coated X-ray Film, 1 1/2 hr

Jan 1, 1961

By Ramesh Malhotra, Hubert E. (Deceased) Risser

THE WORLD Coal, as a source of energy and as a source of coke for the smelting of iron ore, has contributed significantly to the development of every major industrial nation of the world A number of other materials-oil, natural gas, wood, waste materials, water, and, in some applications, nuclear materials -can be used satisfactorily for the generation of heat and energy, but no generally acceptable and economic substitute has been found to supplant coke in iron ore smelting in conventional blast furnaces. In the development of many nations, coal provided the initial source of energy for industrialization Although coal provided more than 60% of the world&apos;s energy each year between 1902 and 1929, oil and natural gas have surpassed it as a source of energy in more recent years (Ref. 38, pp. 439, 441). Despite the rapid rise in importance of other fuels, a considerable amount of the total energy consumed is still supplied by coal. In 1972, coal supplied 32.1 % of the total world energy (Ref. 49, pp. 2-3). To produce this energy, 2.4 billion metric tons of coal were consumed-a 16.0% increase over the amount consumed in 1962. A further worldwide increase in the amount of coal used to supply energy is projected. According to Dr. Karlheinz Bund (Ref. 37, p 145), by the year 2000 world coal consumption could amount to 5 billion mt. Coal Resources and Production The world&apos;s coal resources are estimated to be about 10,872 billion mt. Of this amount, 1,297 billion mt are classified as measured reserves (Ref. 50, p. 57). In Table 13.A.1 the estimates of measured reserves and total resources, recent production, and the ratio of measured reserves to production of major coal-producing countries are shown. About 90% of the world&apos;s total coal resources are estimated to be in the USSR, the United States, and China. The United States ranks second in the world in coal resources, but in measured reserves, it ranks first. Because of the difference in rate at which available coal resources are being exploited, the ratio of measured reserves to actual production varies widely among areas and countries. France and East Germany have the lowest reserve to production ratios, 49.5 and 60.1, respectively. In Mexico, where currently less than 5 million mtpy of coal are produced, the ratio is 1257 For all countries producing more than 200 million mtpy of coal (except East Germany), the ratio ranges from 350 to 670. For the United States, the ratio is 669.7. In Table 13.A.2, distribution of the world&apos;s coal resources by area is shown. More than 97% of the total resources lie in the northern hemisphere, with Asia, including European USSR, having 63.4%. Only 1.9% of the total coal resources are estimat-

Jan 1, 1976

By A. Brown

RAPIDLY rising world demand for mineral products has accelerated depletion of the more readily accessible ores, particularly those of premium grade. Operations must proceed at a faster rate to deeper horizons, where there are problems of ground control that restrict economic recovery of the mineral and introduce new hazards to mine personnel. For some of the new Canadian mining fields severe problems of ground stress are still in the future, but much of Canada&apos;s mineral output comes from well established mines that have reached considerable depths. It must also be anticipated that the depletion of premium grade ores will eventually necessitate mining low grade material at competitive cost, and unsolved problems of ground control can materially increase costs. Studies of ground stress phenomena in underground workings are therefore considered a present-day necessity, especially since these investigations must be a long-term effort owing to the highly complex nature of the problem and the difficulty of making full-scale observations. In recent years the Mines Branch of the Department of Mines and Technical Surveys in Canada has conducted such an investigation. This report of the work is primarily concerned with stress problems in some Canadian coal mines and, in particular, with mine bumps. Mines Branch investigations of this and related problems are carried out by a small team of mining engineers and physicists who, with assistance from geologists, pool their special skills in an integrated program. These Canadian investigations combine a field and laboratory approach. Since data obtained under contrasting mining conditions allow useful comparisons of ground behavior under stress, this article will present data gathered under a wide range of Canadian coal mining conditions. Two contrasting longwalls in eastern Canada will be discussed and two dissimilar pillar extraction operations in western Canada. Locale of Observations In eastern Canada observations are being made in the collieries at Springhill, Nova Scotia. The district&apos;s No. 2 mine, which has a history of bump occurrences dating back to 1917, is currently being worked at a depth of 4200 ft. The mining method is longwall retreating along the strike and the practice is to retreat three walls in line, each about 350 ft long. There is no machine cutting or shooting—the coal is hand-picked and hand-loaded onto face conveyors. There are three rows of hardwood chock block supports parallel to the coal face. These supports are built during the two daily coal loading shifts, and the rear line is withdrawn during the midnight shift. The goaves are partially packed by stone midwalls 12 ft wide which are built forward daily in step with the face advance. The seam dips at 15° and averages 9 ft of strong, well cleated bituminous coal enclosed in competent beds of shales, sandy shales, and sandstones of Carboniferous age. The bumps rarely disturb the retreating longwall faces but manifest themselves as violent upthrusts of pavement in the levels leading to the walls. Observations have also been made in Springhill&apos;s No. 6 mine, which operated in a 5-ft seam of coal at a depth of about 2500 ft. Although No. 6 mine was

Jan 1, 1959

By Toshimi Yamane

The internal friction of cold-worked titanium iso-thermally annealed at temperature below the recrystallization temperature was measured. The internal friction was calculated from the half width of a resonance curve of the specimen which was vibrated transversally by the electromagnetic method. The experimental results were as follows: 1) The specimens annealed for a long time at temperature below the re crystallization temperature after cold working have the strain-amplitude dependent internal friction. 2) The internal friction increased by the cold working was decreased during the isothermal annealing. The reason of decrease of the internal friction is considered to be caused by the annihi-lation of lattice defects. 3) There is a linear relation between logQt-1/Q0-1 and (1/T)2/3 below the recrys-tallization temperature, where Q0-1 is the internal friction standing 24 hr at the room temperature after cold rolling, Qt-1 is the internal friction annealed at T°K for t min. 4) The hardness of the cold-worked titanium does not change by the annealing at 300°C for a long time but decreases by annealing at 400ºand 460°C. METALS, when cold worked, show sharp changes in physical and mechanical properties&apos; The internal friction of cold-worked metals increases sharply and has a maximum value1,2 connected with working de- grees. The increased internal friction of cold-worked metals is recovered by annealing. This phenomenon is the well known effect called Köster effect. The recovery of the internal friction occurs earlier than the changes in tensile properties, hardness, or X-ray diffraction, and is very sensitive to the structure of a metal. The mechanism of the recovery at a temperature lower than the recrystallization temperature is being considered variously by many investigators: there are such views as the annihilation of dislocations by smith,&apos; the rearrangement of dislocations mentioned by Nowick,4 and interaction of dislocation with point defects.5 Smith and Nowick also considered the interaction but it is so difficult for them to explain the rearrangement mechanism systematically, it being not considered a special model; therefore, we do not explain it quantitatively. Experiments measuring the recovery of the internal friction of cold-worked metals were performed by Gordon and Nowick6 on NaCl, and by Smith on copper. In addition, there are many studies, particularly those of measurements on copper by other investigators. There are comparatively many investigations on aluminum and iron which are the cubic system,&apos;-&apos; but only a few on metals of the hexagonal system.10 In view of this, I investigated cph titanium at room temperature and measured the internal friction after annealing isothermally at temperature lower than the recrystallization temperature. SAMPLES AND EXPERIMENTAL METHOD samples for the experiment were cut from a 6-mm titanium plate. The long direction of samples was

Jan 1, 1963

By L. Burris, G. A. Bennett, P. A. Nelson

Staznless steels ave rrzuch less seuel-ely attacketl by zinc lapov than by molten zinc systems. To determine the applicubility of stainless steels fov equipment items which would be exposed only to zinc vapor, the corvosion resistance of several stainless steels to zinc vapor was investigated in 500-hr- exposuves at 900° C. Two austenilic stainless steels, Types 304 and 3-17, suffered severe intergranular attack. Loss of nickel from these steels and micro-probe crnalyses indicated the probable formation of low-melting zinc-rich phases. Good vesistance to attack by zinc vapor, as determined by metallo-9-rpaphic excr)rtination and physical testing, Loas exhibited by Type 405 stainless steel, a jevvitic steel. Type 440C stainless steel, a tnartensitic steel, although suffering considevable loss in weight, was not structurally weakened. At Argonne National Laboratory liquid zinc and zinc-rich alloys are being employed as solvent media in pyrometallurgical processes under development for recovering and purifying discharged reactor-fuel materials.&apos; Because of the high solubility of most metals in liquid zinc,&apos; there are few metals which can serve as container materials for liquid zinc at temperatures much above the melting point. The poor corrosion resistance of the common metals and alloys to molten zinc has been discussed by Eldred.3 DeKany, Lavendel, and Burris4 tested some of the less-common alloys of the nonrefractory metals and found that they also have poor resistance to attack by liquid zinc and Zn-Mg solutions. Of the metallic materials, only some of the refractory metals such as tantalum, tungsten, and molybdenum and their alloys have shown resistance to attack by liquid zinc.4-7 In the process-development work at Argonne National Laboratory, tantalum and tungsten vessels have been used to hold liquid-zinc alloys. These vessels are housed in stainless-steel equipment, principally to permit maintenance of an inert atmosphere and operation at various pressures. In this experimental work, it has often been observed that Type 304 stainless steel suffers little attack by zinc vapor at temperatures up to about 800 °C. In contrast, severe attack occurs in areas where zinc condenses as a liquid. The extent of attack by zinc vapor on several stainless steels was investigated because there are possible useful applications of stainless steel for equipment items which would be exposed only to attack by zinc vapor. These applications include, for example, housings around processing equipment as indicated above and vapor lines leading from zinc stillpots or retorts to condensers. EXPERIMENTAL EQUIPMENT AND PROCEDURE The experimental procedure consisted in exposing stainless-steel test coupons to static zinc vapor for 500 hr at a temperature of about 900°C. The apparatus, shown in Fig. 1, consisted of a 12-in.-long closed tantalum tube jacketed in Type 304 stainless steel to prevent oxidation of the tantalum. A Zn-10 wtpct Mg* alloy charge of 293 g in the bottom of the

Jan 1, 1965

By Henry Sturgis Drinker, Rossiter W. Raymond

Jan 1, 1914