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Discussion of the paper of GEORGE S. Rice, presented. at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2459 to 2492. WILLIAM GRIFFITH, Scranton, Pa.-I notice in the discussions and literature that emphasis is placed on rock dust, shale dust, and limestone dust, and I infer that these different. sorts of rock are ground up to produce this dust. -Is that right? MR. RICE.-That is correct, but we do not have to grind the limestone dust we are using in the experimental mine, as that is obtained from a quarry, and is used just as it comes; we can get it very cheaply, as it is a by-product of the quarries. MR. GRIFFITH.-Have any experiments been made with ordinary dirt out of the fields; could not that be used as ground dust? MR. RICE.-If you dry it and powder it enough so it will float in a, strong air current it might be all right for the barriers, but if it is damp there will be a tendency for it to mat together; then it would be quite useless for making a dust cloud. There might also be another disadvantage if used through the whole mine, if it had very much free silica in it, which is bad for the lungs. Limestone and selected shale dust would not affect the health of miners. MR. GRIFFITH.-In order to do very much good with any of those barriers, they ought to be rather extensively used throughout the mines, and there are few mines that have facilities for grinding up this rock into such a fine dust. If the ordinary earth from a plowed field could be used, even if it were not quite so good, it is more accessible and very much cheaper; therefore, in using it, with the universality of the supply through-out the country, it would tend to stop explosions. MR. RICE (communication to the Secretary*).-In closing, it is well to again emphasize that I do not advocate barriers being a "cure-all" for explosions. It will be generally agreed that prevention is best, not only by means of improved methods of using explosives, and ventilation to prevent accumulations of firedamp, but also by either thoroughly wetting the dust throughout the mine, or else so treating it with rock dust or other inert dust that an explosion cannot start. From my observations I believe that rock dusting. is a practicable method, and has the merit of visibility, and remaining effective for considerable periods, whereas the watering method has to be daily followed up, and if neglected for a short period the mine may become in a dangerous condition. The Germans

Jan 4, 1915

By F. C. von der Weid

THE mining district of São Fidelis, in the northern part of the State of Rio de Janeiro, is situated on the Paraiba River, where it crosses the Serra do Mar (Mountain of the Sea), in the center of a mountainous country having numerous graphitic outcrops. For a long time, these outcrops were irregularly explored by local people, who had little means and no technical advice. A few years ago, the Cia. Brasileira de Mineração de Grafite took over the control of some of the more important outcrops and entrusted to me the task of studying the ores and establishing a flowsheet for a pilot plant to be situated in Sao Fidelis-the ore to be concentrated being mostly of a very high grade. MINERALIZATION AND ORES The rocks of the district are mostly gneiss and crystalline schists, with occasional interstratification of dolomitic limestone belonging to the Archean Brazilian Fundamental Complex. The general direction of the beds is roughly between 60° and 80°E., with variable dip, generally nearly vertical. Mostly, direction and dip of the graphitic outcrops is concordant with the embanking gneisses or schists. These outcrops seem to be aligned in two or three parallel zones (Pádua, São Fidelis, Macabú), the São Fidelis zone being the best known and the most important to date. Two outcrops of the São Fidelis zone, Saudade and São Benedito, are now being exploited. Mining has been carried out, so far, on a small scale. The mineralization consists of a vein of nearly massive graphite in a very compact, partially granitized gneiss, with vertical dip. The vein is most irregular, with nests and lenses irregularly distributed along the fracture plane. The ore consists chiefly (particularly in São Benedito) of massive graphite appearing and disappearing along the main direction of the vein, forming a succession of irregular lenses in a sort of rosary design. The average width is more or less one foot, with variations from zero to 6 feet. The lode minerals are quartz, a little feldspar and garnet (the latter having its origin perhaps in the embedding gneisses), with rare ferruginous clays on the outcrops. In Saudade a little pyrite, pyrrhotite and chalcopyrite is found occasionally, as well as a carbonaceous mineral, very light, black and shiny, with conchoidal fracture, looking like a sort of jet. The composition of this mineral has not yet been established, but it seems to be very complex. The mineralization seems to be hydrothermal at a rather low temperature, perhaps mesothermal. The paragenesis, according to samples from Saudade, seems to be as follows, the earlier minerals being listed first: pyrrhotite, pyrite, chalcopyrite, with quartz concomitant to the three and

Jan 1, 1946

By James Terry Duce

In order to facilitate interpretation of the data in this chapter, we print the following excerpts from circulars to authors, compiled by Mr. Frank A. Herald when he was Vice Chairman for Production of the Petroleurn Division: Generally in Table 1 the unit for presentation of data is a field. For our purposes a field is defined as the whole of a surface area wherein productive, locations are continuous. Such unit commonly includes and surrounds nonproductive areas. Such unit commonly includes a great variety of geologic conditions-—several units of continuous productive reservoirs of distinctly different structure and of distinctly different stratigraphy. Therefore it is hoped that our authors will subdivide "field" so as to enable students to make analyses that may have scientific and/or commercial value. As to each space in the tabulation, it is either (1) not applicable, (2) the proper entry is not determinable, (3) the proper entry is determinable, but not determinable from data available to the author, (4) the proper entry is determinable by the author. In spaces not applicable, the author will please draw horizontal lines; in spaces where the proper entries are not determinable, the author will please insert 2; in spaces where the proper entries are determinable but not determinable from data available to the author, the author will please insert y; in spaces where the proper entries are deter-minable by the author he will, of course, make such entries. Generally, y implies a hope that in some future year a definite figure will be available. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces, the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entries need not be hedged to such extent as in cases where the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use 2. For example, if the total production of a field is known to be between 1,800,000 and 1,850,000, the author may report 1,8xx,xxx; or if the production is between 1,850,000 and 1,900,000, the author may report 1,9xx,xxx. Where a numeral is immediately to the left of x or y, such numeral represents the nearest known number in that position. As to quantity of gas produced from many fields the question will arise as to whether the figures should include merely the gas marketed or should include also estimates of gas used in operations and gas wasted. Although rough approximations may be involved, our figures should represent as nearly as possible the total quantity of gas removed from the reservoir.

Jan 1, 1936

By Fred J. Wright

Originally, mining machines were actuated by purely mechanical mechanisms comprising cams, levers and gear trains, which became more and more complex as demands were made for additional operations that would increase mine tonnage. To simplify these intricate machines, development engineers began utilizing the principles of high-pressure hydraulics long employed for the control of various machine tools. The resulting specificially developed hydraulic systems are. now literally the heart of the mining machine. During world war NO. 2, very little fundamental change in design was made in existing mining machines, but because of the recognition of the merits of hydraulic application to the machines of war, it is reasonably certain that hydraulics will be applied to mining machines in the future to a much greater extent. This potential future indicates that a more thorough knowledge of hydraulics and its maintenance must be incorporated in mine operation. Maintenance of high-pressure hydraulic equipment varies considerably with respect to mine practice and conditions. The success or failure is largely dependent upon the hydraulic fluid and its care. Since all successful hydraulic systems have been designed around the use of mineral oil as the fluid, a complete analysis of this prime factor should be made to make clear the requirements of the fluid in a hydraulic system. Contamination of Oil Manufacturers of mining machinery usually have specified an S.A.E. rating or viscosity index of the proper mineral oil for use with their respective machines without considering the fact that many oils will meet these specifications but will not give the desired life or efficient operation. Hydraulic fluid should be specified as a good grade of mineral oil, such as turbine oil, having rust and oxidation resistance. It must have high chemical stability, high lubricity, and proper viscosity. These factors will minimize maintenance costs by reducing wear and the consequent replacement of parts, and at the Same time will lower costs for the oil by extending its life. Rulk purchases of oil should be limited to small sealed containers provided with a Proper pouring spout, thus reducing the possibility of contamination of the oil before it reaches the mining machine. The introduction of foreign matter, such as sand, water, coal dust and residue oil left in filling containers, will cause untold damage and maintenance expense. Sand, being one of the best natural abrasives1 will soon wear the close tolerances of the various hydraulic mechanisms to an extent that will necessitate complete replacement. Water is considered normally insoluble in oil, but because of the churning action of a hydraulic system water is broken down to particles so small that they remain in suspension. This suspension is known as

Jan 1, 1947

By Fred J. Wright

Originally, mining machines were actuated by purely mechanical mechanisms comprising cams, levers and gear trains, which became more and more complex as demands were made for additional operations that would increase mine tonnage. To simplify these intricate machines, development engineers began utilizing the principles of high-pressure hydraulics long employed for the control of various machine tools. The resulting specificially developed hydraulic systems are. now literally the heart of the mining machine. During world war NO. 2, very little fundamental change in design was made in existing mining machines, but because of the recognition of the merits of hydraulic application to the machines of war, it is reasonably certain that hydraulics will be applied to mining machines in the future to a much greater extent. This potential future indicates that a more thorough knowledge of hydraulics and its maintenance must be incorporated in mine operation. Maintenance of high-pressure hydraulic equipment varies considerably with respect to mine practice and conditions. The success or failure is largely dependent upon the hydraulic fluid and its care. Since all successful hydraulic systems have been designed around the use of mineral oil as the fluid, a complete analysis of this prime factor should be made to make clear the requirements of the fluid in a hydraulic system. Contamination of Oil Manufacturers of mining machinery usually have specified an S.A.E. rating or viscosity index of the proper mineral oil for use with their respective machines without considering the fact that many oils will meet these specifications but will not give the desired life or efficient operation. Hydraulic fluid should be specified as a good grade of mineral oil, such as turbine oil, having rust and oxidation resistance. It must have high chemical stability, high lubricity, and proper viscosity. These factors will minimize maintenance costs by reducing wear and the consequent replacement of parts, and at the Same time will lower costs for the oil by extending its life. Rulk purchases of oil should be limited to small sealed containers provided with a Proper pouring spout, thus reducing the possibility of contamination of the oil before it reaches the mining machine. The introduction of foreign matter, such as sand, water, coal dust and residue oil left in filling containers, will cause untold damage and maintenance expense. Sand, being one of the best natural abrasives1 will soon wear the close tolerances of the various hydraulic mechanisms to an extent that will necessitate complete replacement. Water is considered normally insoluble in oil, but because of the churning action of a hydraulic system water is broken down to particles so small that they remain in suspension. This suspension is known as

Jan 1, 1947

by their overdogmatic picture of geology and their resulting drastic oversimplification and idealization of geologic features. I am in hearty disagreement with the recommendation that geophysics should be done by cooperative work between a geologist and a geophysi-cist. That arrangement would be comparable to doing petrography by having a physicist at the microscope and a geologist sitting by his side. The interpretation of the geological significance of geophysical data can be done efficiently only by a physicist who has become also a good geologist or by a geologist who is also a good geophysicist. Less Well-trained Men The rank and file, composing perhaps two-thirds of the personnel of exploratory geophysics, is not, and should not be, composed of highly trained men. The routine, stereotyped character of the work and the impossibility of promotion of more than a few from these lower ranks even under the best circumstances justify companies in filling the bulk of these rank and file positions with men having only a bachelor's degree at the most. There can be a wide range of training for such positions, although certain lines of study are preferred for certain kinds of work, and different employers have different preferences. For work in gravitational and magnetic prospecting, first preference will be for men having geological training and second for men with civil engineering training. In seismic work, men with geological training are preferred by some employers for computers; physicists, electrical engineers and all whose technical education has covered radio circuits are preferred for the other technical positions. Collegiate training in geophysical prospecting brings no preference and by many employers is given a slightly inferior rating. One large company seldom hires men who have just graduated with a major in geophysical prospecting. This prejudice is based on the reasoning that much of what is learned in college is obsolete or obsolescent, that most of the techniques learned in college will have to be unlearned, because different from those used by the employing company, and that in the long run additional courses in basic physics, mathematics and geology are of more value to a man than the courses on geophysical prospecting. DISCUSSION [This discussion refers to the five papers beginning on page 23 and ending on page 74.1 L. W. Blau,* Houston, Texas.—I have had some rather sad experiences with forecasting. For example, I could not foresee 10 years ago my present occupation, and I do not profess to be able to look ahead 10 years and tell anyone what he will be doing then. Referring to the point raised in the discussion, I do not know, for example, what the price of oil will be 10 years from now. If an appreciable number of

Jan 1, 1940

By Samuel E. Doak

The utilization of rotary kilns, of the well-known cement type, for the preparation of iron ores for the blast furnace, has become of considerable economic importance within the past 10 years in certain localities, notably those where the native ores are lean. Such kilns may be used simply for the agglomeration of ores too fine to be charged into the blast furnace (i.e., ores whose, loss in the dust catchers is excessive, and whose fineness is detrimental to the working of the furnace), or for the desulphurization of lump and fine ores the sulphur content of which does not exceed 6 or 7 per cent. The desulphurizing action can be combined with that of agglomeration provided the kiln is sufficiently large. Other processes have been developed for the same purpose, but while I am not able to draw a comparison between them by reason of lack of sufficient data, it is safe to say that the kiln, if properly dimensioned for the character of ore to be treated, will compare favorably in its results, both as to economy and quality of product, with any other process. It is not, however, as well adapted for the treatment of flue dust as is a sintering operation, on account of the large percentage of fine coke contained therein. Any combustible entering the kiln at its feed end renders the process very much more expensive and unsatisfactory on account of the difficulty of controlling the temperature, also because of the rapidity with which long "rings" form, due to the increased heat at the cooler end of the kiln. The greatest value of the kiln at present is in the treatment of pyrites cinder; that is, the residue from pyrites ore after the extraction of the greater part of the sulphur. This cinder, while high in iron content, has too much sulphur remaining in it to be allowed to form a large part of the blast-furnace burden, without further treatment. It will range in metallic iron from 42 per cent., representing a very low-grade cinder from a domestic pyrites, to 64 per cent. of the residue from the best Spanish ore, and the corresponding silica content will vary from the maximum of about 25 per cent. to 11/2 per cent. The residual sulphur depends largely on the type of burner used in the original desulphurization. In general, the leanest original ores retain the greatest amounts of sulphur. In modern practice the percentage of sulphur in the cinder is rarely as great as six, and seldom lower than one and one-half. Average analyses for iron, silica, and sulphur of the cinders that have come under my personal observation are as follows:

Jan 1, 1916

by their overdogmatic picture of geology and their resulting drastic oversimplification and idealization of geologic features. I am in hearty disagreement with the recommendation that geophysics should be done by cooperative work between a geologist and a geophysi-cist. That arrangement would be comparable to doing petrography by having a physicist at the microscope and a geologist sitting by his side. The interpretation of the geological significance of geophysical data can be done efficiently only by a physicist who has become also a good geologist or by a geologist who is also a good geophysicist. Less Well-trained Men The rank and file, composing perhaps two-thirds of the personnel of exploratory geophysics, is not, and should not be, composed of highly trained men. The routine, stereotyped character of the work and the impossibility of promotion of more than a few from these lower ranks even under the best circumstances justify companies in filling the bulk of these rank and file positions with men having only a bachelor's degree at the most. There can be a wide range of training for such positions, although certain lines of study are preferred for certain kinds of work, and different employers have different preferences. For work in gravitational and magnetic prospecting, first preference will be for men having geological training and second for men with civil engineering training. In seismic work, men with geological training are preferred by some employers for computers; physicists, electrical engineers and all whose technical education has covered radio circuits are preferred for the other technical positions. Collegiate training in geophysical prospecting brings no preference and by many employers is given a slightly inferior rating. One large company seldom hires men who have just graduated with a major in geophysical prospecting. This prejudice is based on the reasoning that much of what is learned in college is obsolete or obsolescent, that most of the techniques learned in college will have to be unlearned, because different from those used by the employing company, and that in the long run additional courses in basic physics, mathematics and geology are of more value to a man than the courses on geophysical prospecting. DISCUSSION [This discussion refers to the five papers beginning on page 23 and ending on page 74.1 L. W. Blau,* Houston, Texas.—I have had some rather sad experiences with forecasting. For example, I could not foresee 10 years ago my present occupation, and I do not profess to be able to look ahead 10 years and tell anyone what he will be doing then. Referring to the point raised in the discussion, I do not know, for example, what the price of oil will be 10 years from now. If an appreciable number of

Jan 1, 1940

By Herbert Ives

THE incandescent gas mantle is of considerable interest from the standpoint of temperature measurement because it presents a series of apparent contradictions to the established laws of radiation on which are based some of our best methods of temperature determination. One of these contradictions is that the mantle of least brightness (of the commercial thoria-ceria group) is the one having the highest temperature; this, though explicable without any violation of radiation laws, was long a stumbling block to the understanding of the performance of the mantle. Another anomaly is that the energy radiated by the mantle decreases with the rise of temperature, thus apparently invalidating total radiation methods of pyrometry, based on the fourth-power law. The discussion of methods of measuring mantle temperature which follows, is largely taken from an extensive study of the physics of the Welsbach mantle. 1 The incandescent gas mantle consists of a skeleton of refractory oxide of very light weight and open structure, formed by the ignition of a cotton or silk "stocking" previously thoroughly impregnated with salts of certain rare earths. The mantle of commerce is a mixture of approximately 99 parts of thorium oxide with 1 part of cerium oxide. This mixture, discovered largely by accident, gives luminous radiation many times greater than that from either of the constituents taken alone. It is customary to speak of the thoria as the "base" and the ceria as the "colorant," and the commercial mantle represents one of a family in which an oxide of low emissive power is employed as a base, which will assume a high temperature, while a small amount of some other oxide of high visible emissive power is added, which will reduce the temperature of the mantle but little. This is, in general, the most efficient- way, from the standpoint of visible emission, to utilize a substance of high emissive power in the visible spectrum. But it is not necessary. that two substances should be employed to produce a radiator

Jan 9, 1919

By Dart Wantland, C. A. Heiland

There once was a little kid, whose lot was a very tough one until he grew up. His parents did not have much in common; from all indications, it is probable that the child was not wanted. His father Geology and his mother Physics separated shortly after his birth, which occurred during the World War amid a smoke screen of mathematics. He was kicked around a great deal. His parents could not agree on a name, and they finally christened him "Geophysics," for short. His relatives insisted that the name should be "Geophysical Prospecting," "Geophysical Exploration" or "Exploratory Geophysics"; though the youngster has grown up by now, this battle is still going on. His father did not think the child would amount to much until he began to show some unexpected talents, which were acquired, no doubt, from his mother Physics. His progress caused his father no little worry, and he began to wonder whether his offspring would help him in his business when he grew up or would set up shop in competition with the old man. His aunt Petroleum watched his growth with benevolent interest; his uncle Mining remained rather skeptical and cousin Civil Engineering not only assumed the attitude of the man from Missouri but was not much convinced even after he had been shown. Making a long story short, the kid decided that he had to stand on his own feet and get along as best he could. Having come from a good family he possessed some outstanding characteristics such as resourcefulness and a reasonable amount of business ability. He therefore decided that it would be to his advantage to follow in his father's and mother's footsteps as much as possible, and develop the good qualities of both. As a result, the youngster did fairly well for himself, and his relatives decided that it might be to their advantage to be on better terms with him. Father Geology had come to the conclusion that the boy could be very helpful to him and now wanted him to live in his house. His mother, who had brought him through the teething and measles stages, felt quite capable of bringing up the boy without the help of his father; and, as the fairer sex will do, would confide to a neighbor every now and then that his

Jan 1, 1940

By C. A. Heiland

THERE once was a little kid, whose lot was a very tough one until he grew up. His parents did not have much in common; from all indica-tions, it is probable that the child was not wanted. His father Geology and his mother Physics separated shortly after his birth, which occurred during the World War amid a smoke screen of mathematics. He was kicked around a great deal. His parents could not agree on a name, and they finally christened him "Geophysics," for short. His relatives insisted that the name should be "Geophysical Prospecting," "Geophys-ical Exploration" or "Exploratory Geophysics"; though the youngster has grown up by now, this battle is still going on. His father did not think the child would amount to much until he began to show some unexpected talents, which were acquired, no doubt, from his mother Physics. His progress caused his father no little worry, and he began to wonder whether his offspring would help him in his business when he grew up or would set up shop in competition with the old man. His aunt Petroleum watched his growth with benevolent interest; his uncle Mining remained rather skeptical and cousin Civil Engineering not only assumed the attitude of the man from Missouri but was not much con-vinced even after he had been shown. Making a long story short, the kid decided that he had to stand on his own feet and get along as best he could. Having come from a good family . he possessed some outstanding characteristics such as resourcefulness and a reasonable amount of business ability. He therefore decided that it would be to his advantage to follow in his father's and mother's foot-steps as much as possible, and develop the good qualities of both. As a result, the youngster did fairly well for himself, and his relatives decided that it might be to their advantage to be on better terms with him. Father Geology had come to the conclusion that the boy could be very helpful to him and now wanted him to live in his house. His mother, who had brought him through the teething and measles stages, felt quite capable of bringing up the boy without the help of his father; and, as the fairer sex will do, would confide to a neighbor every now and then that his

Jan 1, 1938

By C. A. Heiland, Dart Wantland

There once was a little kid, whose lot was a very tough one until he grew up. His parents did not have much in common; from all indications, it is probable that the child was not wanted. His father Geology and his mother Physics separated shortly after his birth, which occurred during the World War amid a smoke screen of mathematics. He was kicked around a great deal. His parents could not agree on a name, and they finally christened him "Geophysics," for short. His relatives insisted that the name should be "Geophysical Prospecting," "Geophysical Exploration" or "Exploratory Geophysics"; though the youngster has grown up by now, this battle is still going on. His father did not think the child would amount to much until he began to show some unexpected talents, which were acquired, no doubt, from his mother Physics. His progress caused his father no little worry, and he began to wonder whether his offspring would help him in his business when he grew up or would set up shop in competition with the old man. His aunt Petroleum watched his growth with benevolent interest; his uncle Mining remained rather skeptical and cousin Civil Engineering not only assumed the attitude of the man from Missouri but was not much convinced even after he had been shown. Making a long story short, the kid decided that he had to stand on his own feet and get along as best he could. Having come from a good family he possessed some outstanding characteristics such as resourcefulness and a reasonable amount of business ability. He therefore decided that it would be to his advantage to follow in his father's and mother's footsteps as much as possible, and develop the good qualities of both. As a result, the youngster did fairly well for himself, and his relatives decided that it might be to their advantage to be on better terms with him. Father Geology had come to the conclusion that the boy could be very helpful to him and now wanted him to live in his house. His mother, who had brought him through the teething and measles stages, felt quite capable of bringing up the boy without the help of his father; and, as the fairer sex will do, would confide to a neighbor every now and then that his

Jan 1, 1940

Discussion of the paper of GEORGE K. BURGESS and SIR ROBERT A. HADFIELD, presented at the New York meeting, February, 1915, and printed in Bulletin No. 98, February, 1915, pp. 455 to 468. ALBERT SAUVEUR, Cambridge, Mass.-There is a definiteness and finality in the investigations that have been conducted by the Bureau of Standards and in the method of presenting the results that is most satisfactory and refreshing.. A year ago Dr. Burgess and his co-workers investigated the question of critical points in carbonless iron, and they settled the question once for all. No one can now claim that the thermal point A2 in carbonless iron does not exist. At the past meeting of this Institute in Pittsburgh, Dr. Burgess showed the worthlessness of the shrinkage clause. To my mind after his demonstration no one can again claim that the shrinkage clause renders any service. He also showed us that it was a practicable proposition to use pyrometers in steel work in order to ascertain the finishing temperatures of rails. No one can again come before this body and make the claim that it is not a practical proposition. And now Dr. Burgess shows us that steel ingots can be made in a commercial way, practically free from pipe, from segregation, aid from blow holes. It places again before us in a very clear manner the question of piped ingots and of segregation, a question which has been debated for 20 years or more. I know very well the attitude of the standpatters in the matter. They claim that most of the pipe is removed in the discard, and that if a little is left it is so thoroughly welded that it does no harm. I for one am not convinced of the soundness of the argument. I do not believe there is any one present who would claim that, given an ingot free from pipe, free from segregation, and free from blow holes, better rails will not be made out of that ingot than out of the ordinary piped or segregated metal which is used by almost all of our steel mills. In my opinion, if we give our sanction to the casting of steel in the shape of piped or segregated steel ingots, we are guilty. If we give our sanction to the rolling of rails from such metal, we are guilty. It is our duty as experts, as steel makers, and as steel consumers to make and to use the best steel obtainable on a commercial basis, for the manufacture of rails. Now, we have been shown that sound ingots can be produced from which superior rails can be made. If we do not insist upon these sound ingots, then we fail in our duty. I think that the art of casting steel ingots has advanced to such a point that the casting of steel ingots piped and segregated ought no longer to be tolerated.

Jan 5, 1915

By H. W. Schadler

The superplastic behavior of low carbon and manganese bearing steels has been evaluated. The results of elevated-temperature stress-strain rate and elongation tests are reported which indicate that high strain rate sensitivity (>0.5) and adequate elongations are achievable in ultrafine-grained steels 1 to 2 p, but at strain rates which are not commercially attractive. It has been demonstrated that the fine grain size is retained after long times and high strains if the temperature is kept within the range of the two-phase (a + ?) field. INTEREST in superplasticity has been stimulated by the desire to: 1) understand the origin of, and mechanisms responsible for, the large uniform elongations observed, and 2) exploit this property for commercial advantage in metal forming operations. Although the Zn-22 wt pct Al alloy presently being studied as a model material1-5 may find application in sheet forming and extrusion, the potential of super-plasticity should best be realized in large tonnage materials, such as steel and aluminum alloys. The degree of superplasticity in low-carbon and manganese-bearing steels has been evaluated. The results of elevated-temperature stress-strain rate and elongation tests on ultrafine grain size material are reported. Avery and Backofen6 and Hart7 have shown that geometrically stable flow leading to extensive uniform elongation in the tension test is associated with high values of the strain rate sensitivity, m, defined: Lozinsky had reported that titanium and zirconium experience permanent deformation if subjected to a constant load and cyclic heating through the temperature range of the phase transformation. Although strain rate sensitivities in excess of about 0.2 had not been reported previously for steel, permanent deformation had been observed11-13 in a wide variety of steels subjected to a constant load and cyclic heating through the temperature range of the a-? phase transformation. Thus by analogy, steel could be expected to exhibit high strain rate sensitivity but only in the a + ? condition. High strain rate sensitivity has been observed at 650°C (a + Fe3C), but not reported as such, by Bailey, Dickenson, and pearson14 in 1931 at a strain rate of about 10-9 per min. It then remained to determine whether high tensile elongations would be observed in a rate-controlled test at constant temperature and at what strain rate strain rate sensitivity values greater than 0.5 would be observed. Since previous experience8 had indicated the importance of fine grain size to realizing high m at reasonable strain rates, it was first necessary to produce an ultrafine grain size and then keep the grains from growing during the test. The results of this investigation show that fine grain size can be readily produced16 and maintained by restricting the temperature of testing to below the ? transus. Further, superplasticity (high m and large uniform elongation) is observed. However, the strain rate range is only marginally useful for commercial forming operations with the finest grain size produced. MATERIAL The material investigated initially was a 1.9 wt pct Mn, 0.42 wt pct C, hot-rolled bar previously used by Low and Turka1015 and available in the laboratory. The 0.500-in. round was cold-rolled to a 0.090-in. flat, annealed for 4 hr at 850°C in argon, air-cooled, and cold-finished to 0.050 in. Subsequently, four additional steels of the compositions given in Table I were investigated to explore the effects of manganese, carbon, and test temperature on the observed stress-strain rate behavior. These steels were melted under argon, cast to 0.75 by 2 by 5 in. slabs, hot-rolled at 850°C, surface-finished to 0.13 in., and cold-finished to 0.050 in. Sheet tensile specimens 0.200 in. x thickness with 1- or 2-in. gage length were cut parallel to the rolling direction. Table I also includes the nominal transformation temperatures for the AISI 1340 and the four experimental steels. EXPERIMENTAL PROCEDURE Production of Fine Grain Size. Ultrafine grain size (1 to 5 p) was considered essential for this studv. Grange16 has described two techniques for producing

Jan 1, 1969

By A. Cochardt, D. H. Feisel

HE success of the sintered aluminum powder material (SAP)' in raising the maximum useful temperature of aluminum alloys has stimulated effort in investigating similar systems in which the metallic matrixes have higher melting points. Examples of such systems which have been studied are nickel-alumina,2, 3copper-silica,4 copper-alumina,4 titanium-cerium oxide,5 and 80/20 nickel-chromium,8 cobalt,= and molybdenum7 matrixes with various hardeners. Conventional precipitation-hardened high-temperature alloys are often thermally unstable in service. The original fine particles that are responsible for good strength properties grow in size at elevated operating temperatures, a process termed "over-aging." This growth of precipitated particles causes a gradual loss in strength properties. A previous paperb describes the factors that govern the process of overaging, and estimates the time required for overaging of a nickel-alloy matrix dispersion-hardened by various precipitates such as are found in current high-temperature alloys, and by alumina. These calculations indicate that nickel-base alloys hardened with Ni3Al, Tic, or TiN are quite unstable at 1340" F (727°F). Such alloys should overage within a few hours at that temperature. A nickel-base alloy hardened with alumina, on the other hand, should behave differently. It should not overage appreciably within a thousand years. It was further shown8 that the thermal stability of the oxide-hardened alloy is mainly due to the low solubility of oxygen in equilibrium with alumina in the nickel-base matrix. Since the oxygen solubility is small, little oxygen can diffuse, and structural changes require very long times. This paper illustrates the effects of time and temperature on the structural stability of nickel alloy matrixes hardened by dispersions of Ni3A1, Ni3Ti, Tic, and alumina, and of nickel-chromium matrixes hardened by alumina. Hardness measurements and metallography have been used as a measure of structural stability. EXPERIMENTAL PROCEDURE Using the best information from published phase diagrams,'-l4 compositions of the Ni-Al, Ni-Ti, and Ni-Ti-C alloys were determined so as to have 5 vol pct of precipitate at 1350° F(732°C), the temperature selected to illustrate the effect of time on structural stability. Table I lists the chemical compositions of these alloys. Standard laboratory melting and alloying techniques were used in preparing ingots of the F-Series of alloys. The cast ingots, 1 3/4 in. in diam, were forged to 3/8-in. diam rods.

Jan 1, 1960

By J. R. Campbell

A dozen years or so ago, the general superintendent of our company, now the president, Mr. W. H. Clingerman, asked me to study the coal-washing problem. This work brought me into contact with the best washery men of the country. I investigated many kinds of coal-cleaning schemes, made numerous tests, and collected voluminous data, yet I confess frankly that I have had little practical washery experience and that little has been at the Middlefork washery of the United States Fuel Co. at Benton, Franklin Co., Ill., which was put in operation last fall. While this washery installation may not be the "last word," I am quite sure it embodies some long steps in advance of the older designs and constructions. From the washery man's standpoint, the removal of pyrites or marcasite, a disulfide of iron, is the one vital problem, and the one productive of the most beneficial results, so far as elimination of sulfur is concerned. Sulfates and so-called organic sulfur occupy quite a sec-. ondary position and are generally lost sight of in coal washing. The elimination of sulfur in coal in the past has usually been accomplished by jigging in water, but lately concentrating tables have been successfully employed. The flotation process has been applied to fine coal, but is hardly considered practicable. Coal washing is rapidly coming into its own, due to the depletion of low-sulfur coals for coking purposes, and we predict that soon the same careful attention will be given to the design and construction of coal washeries that is now being given to byproduct plants and other allied industries. Heretofore, coal washing has been considered only an incidental and necessary evil instead of the big problem it is—one worthy of the most careful study by men well trained along technical lines and capable of delving into the fundamental principles. Preparation oF Coal It is usually necessary to crush the mine-run coal before sending it to the jigs, the degree of crushing depending on the occurrence of the sulfur and other impurities in the coal and the type of jig over which it is to be sent. The feldspar jig requires finer and more uniform crushing

Jan 1, 1920

By I. Fatt

Laboratory relative permeability data on reservoir rock are obtained on samples which are not subjected to overburden pressure during the permeability measurements. These data are then used for calculating the performance characteristics of reservoirs in which the rock is under the pressure of the overburden. Recent observations have shown that the permeability and porosity of reservoir sandstones are decreased by application of overburden pressure. These observations led us to a study of the effect of overburden pressure on the relative permeability characteristics of sandstones. A previous note from this laboratory1 showed that overburden pressure, simulated by applying hydraulic pressure to the outside of a plastic mounted core. caused a reduction in permeability of the core by as much as 50 per cent at 10,000 psig. In a multiphase fluid flow system, the relative permeability at a given saturation will change if the permeability or the effective permeability changes but not if both permeability and effective permeability change by the same ratio. The tests described in this note were made to determine the effect of overburden pressure on permeability and effective gas permeability in the gas-oil system. The gas-oil system was chosen because the available equipment was best suited for studying this system. The resultant data can be applied to other systems of interest because the gas permeability in the gas-oil system is the permeability of the nonwetting phase and, as such, is equivalent to the gas permeability in the gas-oil-water system and to the oil permeability in the oil-water system. EXPERIMENTAL METHOD Cylindrical test plugs, one in. in diameter and one in. long, were cut from sandstone core samples from three different reservoirs. After extraction in toluene, the plugs were mounted in Lucite by conventional core mounting methods.3 The core properties are given in the legend in Fig. 1. The mounted cores were machined to fit the apparatus shown in Fig 4. Air permeabilities as a function of overburden pressure were measured by connecting lines (1) and (2) to a conventional air permeameter. To measure porosity changes as a function of overburden pressure, the lines leading to (1) and (2) and the core were saturated with kerosene; line (1) was capped and a small bore precision calibrated pipet was connected to (2). Changes in pore volume of the core as overburden pressure was applied were noted by reading the amount of kerosene produced into the pipet. To correct for the change in volume of the lines inside the hydraulic cell as a function of pressure, a pressure-vs-volume run was made with a solid Lucite cylinder substituted for the core. The change in volume of the lines was about 10 per cent of the change in pore volume of the core. No correction was needed for the permeability measurements because there was no measurable pressure drop in the lines at the maximum overburden pressure. Relative gas permeabilities were measured by the stationary liquid method described by Osoba, et al.' Gas saturations were obtained by allowing the kerosene from a kerosene saturated core to evaporate out. This procedure was followed

Jan 1, 1953

By C. W. Wark, Fred Wise

The Getchell mine, a comparatively recent gold discovery, is in the old Potosi mining district, Humboldt County, Nevada. All ore is mined from open pits using Diesel shovels and gasoline trucks. Two types of ore are mined, oxide and sulphide. Oxide ores are siliceous or shaly; sulphide ores either gougy, siliceous or shaly. In mining, the sulphide ore is segregated into hard and gougy ore, because the gouge must be dried before it can be crushed. The oxide ore is not segregated. General Metallurgy The oxide ore is the leached outcrop that overlies the sulphide ore body. All of the iron and arsenic sulphides found in the sulphide ores have been thoroughly oxidized. The sulphur and arsenic have been leached out while the iron is present as hematite and limonite. The oxide ore is amenable to direct cyanidation, and although no visible free gold is present it is released at a comparatively coarse grind. The sulphide ore is more refractory, since the gold is all of micron size and some of it is locked in fine sulphides. It has been established microscopically that the free gold is coated with an impervious shell, which is probably some form of iron compound. The sulphide ores contain from 1.5 to 2 per cent of arsenic, which is present as orpiment and realgar with minor amounts of arsenopyrite. The orpiment and realgar are of a later mineralization than the gold and are barren. Roasting and washing of the sulphide ore prior to cyanidation is necessary to eliminate , the arsenic, to alter the gold coating from an insoluble form to a soluble form, and to release the gold associated with the fine sulphides. Washing the ground calcine in weak sulphuric acid, trona, or hot water are beneficial in the order named, but to date the water is the best from an economic standpoint. Metallurgical tests as well as plant practice indicate that a certain amount of gold cannot be recovered even by going beyond economic practices. On this basis metallurgical results are viewed in the light of an optimum tailing rather than a percentage of extraction. Milling Practice Crushing (Fig. I).—There are three primary ore bins, one each for oxide ore, gougy sulphide ore, and hard sulphide ore. In front of each bin a substantial yard is maintained, which makes it possible to Stockpile 2500 tons of oxidized ore, 1000 tons of hard sulphide ore, and 1000 tons of gougy sulphide ore. The bins are fed by a 60-hp. caterpillar bulldozer from the stockpiles. Fig. I shows the method and

Jan 1, 1943

By Fred Wise, C. W. Wark

The Getchell mine, a comparatively recent gold discovery, is in the old Potosi mining district, Humboldt County, Nevada. All ore is mined from open pits using Diesel shovels and gasoline trucks. Two types of ore are mined, oxide and sulphide. Oxide ores are siliceous or shaly; sulphide ores either gougy, siliceous or shaly. In mining, the sulphide ore is segregated into hard and gougy ore, because the gouge must be dried before it can be crushed. The oxide ore is not segregated. General Metallurgy The oxide ore is the leached outcrop that overlies the sulphide ore body. All of the iron and arsenic sulphides found in the sulphide ores have been thoroughly oxidized. The sulphur and arsenic have been leached out while the iron is present as hematite and limonite. The oxide ore is amenable to direct cyanidation, and although no visible free gold is present it is released at a comparatively coarse grind. The sulphide ore is more refractory, since the gold is all of micron size and some of it is locked in fine sulphides. It has been established microscopically that the free gold is coated with an impervious shell, which is probably some form of iron compound. The sulphide ores contain from 1.5 to 2 per cent of arsenic, which is present as orpiment and realgar with minor amounts of arsenopyrite. The orpiment and realgar are of a later mineralization than the gold and are barren. Roasting and washing of the sulphide ore prior to cyanidation is necessary to eliminate , the arsenic, to alter the gold coating from an insoluble form to a soluble form, and to release the gold associated with the fine sulphides. Washing the ground calcine in weak sulphuric acid, trona, or hot water are beneficial in the order named, but to date the water is the best from an economic standpoint. Metallurgical tests as well as plant practice indicate that a certain amount of gold cannot be recovered even by going beyond economic practices. On this basis metallurgical results are viewed in the light of an optimum tailing rather than a percentage of extraction. Milling Practice Crushing (Fig. I).—There are three primary ore bins, one each for oxide ore, gougy sulphide ore, and hard sulphide ore. In front of each bin a substantial yard is maintained, which makes it possible to Stockpile 2500 tons of oxidized ore, 1000 tons of hard sulphide ore, and 1000 tons of gougy sulphide ore. The bins are fed by a 60-hp. caterpillar bulldozer from the stockpiles. Fig. I shows the method and

Jan 1, 1943

By Albert Sauveur

As director of the Division of Metallurgy of the Technical Section of the Air Service, American Expeditionary Forces, from August, 1917, to January, 1919, I devoted much time to the study of the steels best suited to the construction of aircraft. It became apparent at a very early stage of my investigation that the practice of builders varied greatly in regard to the number of different steels to be used, to the kinds of steels, and to their treatment. Some manufacturers employed as many as fifteen steels while the builder of one of the newest motors, favorably passed upon in the United States, assured me that two or, at the most, three kinds of steel were all he needed to produce satisfactory results. In the matter of treatment, the manufacturers were also greatly at variance. Some treated their steel with considerable refinement while others paid but scant attention to this feature. Some manufacturers case-hardened many parts, while others used the case-hardening process sparingly, if at all. Nickel-chromium steels were used at some works for case-hardening while at other plants this treatment was applied exclusively to carbon steels. Air-hardening nickel-chromium steel was used extensively by some and not at all by others. Considerable variance existed likewise in regard to the steels used for admission and exhaust valves. The conclusion was obvious, that no two manufacturers of airplane motors held like opinions as to the steels to be used or as to the treatment they should receive. Was it to be inferred from this that the many committees and associations that had been created, in part at least, for the standardization of aircraft steels had failed to make proper recommendations or that the manufacturers had ignored their recommendations ? Confining our inquiry to the committees and associations that had dealt with this question in England, France, and the United States, it was found that in Great Britain the British Engineering Standards Committee, now the British Engineering Standards Association, had devoted much time to the problem of satisfactory standards for aircraft steels. In April, 1918, this Association presented a set of specifications described as "British Standard Specifications for Aircraft Steels for Government Purchases in the United States of America." They included twenty-one different steels and, as the title indicates, were drawn for the

Jan 1, 1920