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By Henry B. Smith, S. Paul Lindau

ThREe years ago it was decided by the management to granulate the matte that is produced in the smelter of the St. Joseph Lead Co. at Hereulaneum, Mo., thereby doing away with a large amount of labor in handling the matte and in subsequent crushing. On Mar. 1, 1915, the granulator was put in operation and up to Jan. 1, 1916, 18,735 tons had been granulated. The four blast furnaces have a daily output of about 280 tons of pig lead and 100 tons of matte assaying about 11.0 per cent. Pb. It is expected that projected improvements in roasting methods will eliminate more sulphur from the charge, and cut down the matte-fall to about one-half of the present figure. The blast furnaces are tapped into movable forehearths or settlers, 6 ft. by 4 ft. by 22 in., the slag overflowing into 27-cu. ft. slag cars which are hauled to the dump by electric locomotives. Previous to the adoption of granulation, the matte was tapped from the forehearths into small slag pots which were dumped after cooling. The matte cakes were broken with sledges, and transported to the crushing plant for fine crushing and screening. Here the matte was reduced to 1/4-in. size before being fed to the roaster bins. A Wedge and a Holthoff mechanical furnace are used for preroasting before sintering on the Dwight and Lloyd machines. The matte is returned to the furnaces as an iron flux until the gradually accumulating copper content reaches about 7 per cent., after which it is put aside to be concentrated in a small copper blast furnace, the resultant high-grade matte being sold. When the matte does not settle readily from the slag, two settling devices are often used, the second one being a large catch-pot, which gathers any matte that may overflow from the forehearth, the slag then overflowing from the catch-pot into the slag cars. When full of matte, the catch-pot is removed, allowed to cool, and the contents broken and crushed. a With the present plan of granulating, the matte is tapped into 6-cu. ft. iron ladles. These are transported to the granulating plant by a 5-ton

Jan 1, 1917

By Ralph Arnold

While much geological work and drilling have been done in Venezuela, the incompleteness of geological evidence obtainable and the restricted areas in which drilling has been done make any estimates of oil resources extremely speculative. Nevertheless, it is felt that the data given are justified, in the belief that the ideas of a geologist familiar with the region are better than those of a promoter. The oldest beds of interest to oil men are those of the Cretaceous, which are well developed in eastern Venezuela and about parts of Lake Mara-caibo. In both cases, a hard massive limestone is overlain by a great thickness, most of which is shale. In the west, in places this shale is more than 2000 ft. (610 m.) thick, while in the east it-mag attain 3500 ft. (1067 m.). The limestone and parts of the shale are oil producing. In the east, the Tertiary where present is almost entirely covered by the Quarternary, but in the west it is well developed. In probable unconformity over the Cretaceous shales is found a series of sandstones and shales, which may be called the lower coal series. It is well developed southwest of the lake, where it is the oil container, and is probably the lowest series exposed east of the lake. Above this is the Pauji shale, which is probably the point of origin of all the oil east of Lake Maracaibo and in the State of Falcon. It has a thickness of about 3000 ft. (914 m.) in the Mene Grande region. The upper coal series is developed as a great thickness of sands, shales, and clays, with some partly consolidated limestone. Its thickness may be as great as 10,000 ft. It is the oil container of the Falcon-El Mene region and a probable location for oil in some of the area about the lake. It may or may not include the so-called Maracaibo series in which the oil is found at Mene Grande. Over much of Venezuela, the Quarternary is present in unknown thickness, which probably is not great. It obscures oil structure in all cases and presents the greatest hazard of oil exploration for the fields which probably exist below.

Jan 1, 1923

By Alex Frosch, Lynn G. Howell

In a previous article1 we have described a technique for measuring the relative intensities of gamma rays from the radioactive elements occurring naturally in geological formations along the walls of a borehole. The apparatus consisted of two Geiger-Müller tubes mounted inside a pressure-tight chamber. Each counter tube was coupled separately to an amplifier and a frequency meter at the surface by means of a multiconductor cable upon which the chamber was suspended. The output currents of the two frequency meters were recorded on a photographic paper as the chamber was moved in the hole. These traces showed remarkable correlation with the geologic formations, as evidenced by comparison with commercial electrical logs.2 Owing to the penetrating power of the gamma rays, logs may be taken in both open and cased boreholes. The apparatus has recently been changed somewhat. One of the counter tubes has been removed and a stage of amplification has been added inside the chamber. This arrangement seems to give a more favorable signal-to-noise ratio and satisfactory logs can be now made in cased holes and also in open holes as previously. Briefly described, the chamber moving in the hole is made of 3½-in. drill pipe and is about 10 ft. long. There is an additional extension about 2 ft. long at the top, inside which cable connections are made. The Geiger-Müller tube is mounted inside the bottom end of the chamber. Above this is the vacuum-tube amplifier with its batteries and transformer. In the top part of the chamber, small 45-volt batteries are mounted, which in part supply the high voltage for the counter tube. Additional voltage is supplied from the surface through the multiconductor cable upon which the chamber is suspended. Also, the output of the transformer in the single-stage amplifier is coupled to another single-stage amplifier at the surface through this cable. The surface amplifier is coupled to the Thyratron-controlled frequency meter, the tank circuit of which consists of a one megohm resistor across which is a bank of condensers varying in

Jan 1, 1940

By J. P. Lesley

The old do not love to see the young pass away from the light of the sun before them. Fathers would fain keep their sons by their side to the. end of life ; but the old Greeks, who loved the old gods, were wont to moderate their grief with the sweet superstition that only those whom their gods especially loved died early. The Christian church found consolation in that superstition applied in a new form to its new sorrows, and paid its most enthusiastic devotion to the memories of its young and beautiful martyrs. The natural science of our century is robbing us fast of this and all other superstitions, sweet as well as bitter, and leaving us for consolation to the teaching—colder, yet kinder—of personal fortitude and that optimism Which intelligently translates the Cosmos of Humboldt back into its old name of the Harmonia of Pythagoras. The Homeric Kataclothes, the three fates, are dead and gone for us, with that old world which comprehended none of the laws of cause and effect, and sorrowed for those who were cut off from the land of the living without hope of more than a shadowy existence beyond the river of death. All the more the ancients cherished the memory of their dead and lavished their choicest art upon their monuments. We moderns have lost the monumental arts, but we better keep the monuments which our dead leave behind them. No one of us who has done good work can fail to be remembered; and in an Institute like this, which keeps the press at work, an immortality in the memory of men is more possible, more certain, for every one of its members than the greatest heroes of antiquity could anticipate for themselves. In old apocalyptic times the works of men followed them through death to the throne of God to be their advocates in judgment, but in these modern times our works remain this side the grave, to follow the name of the departed one as it takes its course along the history of his peculiar art or science advancing slowly to perfection. We write the epitaph, not upon the mouldering stone of a tomb, but on the pages

Jan 1, 1890

By C. R. Johnson, R. A. Greenkorn, G. W. Widner

This paper describes a short, simple well-testing procedure evolved from unsteady-state concepts to appraise wellbore damage in water-input wells. Input rates are changed at specific intervals over a 30-minute period and the wellhead pressure recorded at the end of each interval. From these data, the pressure drop due to the "skin" can be computed. This pressure drop in terms of psi/B/D of input rate is referred to as the "skin factor". Two of these variable-rate tests are required to determine change of wellbore damage and to evaluate well-treatment techniques. There are several advantages to the variable-rate procedure. The necessary data can be obtained with wellhead gauges and meters. There is little interference with normal operations. The short testing period eliminates many interpretative difficulties that come from interference from adjacent wells. The shut-in period required for standard tests before the plot of pressure vs log of time attains a straight line is often 12 hours or more. Such a time period is incronvenient, especially when a well must be tested repeatedly to evaluate change in wellbore characteristics. This variable-rate procedure has been successfully npplied to water-input wells in three fields. For some of the wells, skin factors were calculated from both the standard and the variable-rate tests. These results show good agreement. THEORY OF THE VARIABLE-RATE PROCEDURE In many waterflood input wells, the pressure in the wellbore differs from the pressure in the reservoir immediately adjacent to the well because of the restriction of flow through the skin of the well. If the true pressure of the reservoir at the well, p,, is that pressure which would exist in the well if no skin were present, and p,' is the actual pressure as measured in the well, this difference, is the skin effect. Fig. 1 shows the change in skin effect with change in flow rate. As the flow is reduced, the skin effect is reduced by an amount equal to the change in wellbore pressure minus the change in reservoir pressure. The equation of pressure change without skin using the point-source solution of the diffusivity equation is (after van Everdingen')

By Doon Gibbs

In this talk, we review highlights of x-ray magnetic scattering studies performed during the last decade, concentrating at the beginning on experiments on the rare earth metal holmium.(1-4) Besides intrinsic interest in the x-ray scattering cross-section and its description, studies of this type are motivated by the possibility that new structural and magnetic properties of rare earth metals might be revealed, and that new techniques may thereby be developed. As a result, interest in x-ray magnetic scattering experiments. has grown rapidly during the last 10 years particularly, with the regular application of synchrotron radiation techniques- Magnetic scattering experiments have by now been performed at most of the x-ray synchrotrons around the world. In addition, insertion .device beamlines dedicated to x-ray magnetic scattering experiments are planned at each of the next-generation storage rings presently under construction in the United States (APS), Europe (ESRF), and Japan (SPRING-8). Generally, the results of x-ray magnetic scattering experiments may be analyzed within two regimes of the incident x-ray energy, namely, in the limit of high x-ray energies, when the incident x-ray energy lies above the excitation energy of any absorption edge, and at resonance, when the incident energy lies near an absorption edge. In the high energy limit, the amplitude for x-ray magnetic scattering has the simple form [L(Q)?A + S(Q)?B](5-7) Here, L(Q) and S(Q) refer to the Fourier 'transforms of the atomic orbital and spin magnetization densities, respectively, and the vectors A and B depend on the incident and scattered wavevectors and on the: incident and scattered polarization vectors. 7) Because the vectors A and B are not identical, the polarization dependence of the orbital contribution to the magnetic cross-section differs from that of the spin contribution. This leads to the possibility that the orbital and spin magnetization densities maybe distinguished, in x-ray scattering experiments. The same distinction is not directly possible by neutron diffraction techniques (in dipole approximation, where the polarization dependence of the orbital contribution is identical to that of the spin contribution), and is important to a fundamental understanding of the electronic structure of magnetic materials. A particular

Jan 1, 1992

By J. W. Richards

There are two essentially different 'types of case-hardening processes; that using a dry mixture in which the object to be case-hardened is packed and kept for the necessary time at the necessary temperature, and the "liquid" proccss, employing a bath of fused salts into which the object is immersed and which by immediate contact case-hardens the surface of the article. The Shimer process belongs to the second class, and was a war emergency invention. Of the liquid melts used as baths, the most effective and most frequently used are melted potassium cyanide and melted sodium cyanide. These may be used either pure or mixed with salts that reduce the melting point and the percentage of .cyanide present. The use of these baths since 1914 has met many commercial difficulties because of the high price and frequent commercial scarcity of the cyanide salts; at present sodium cyanide has practically entirely displaced potassium cyanide. Another trouble is the danger to the workmen handling the cyanide salts, which are extremely poisonous, and the annoying and poisonous vapors or gases given off in the workshop, unless an effective system of hoods and ventilation is provided, so as to prevent the gases from the baths mixing with the air of the room. Porter W. Shimer, of Easton, Pa., has invented a substitute1 for the bath of melted cyanides which case-hardens with equal or greater facility and effectiveness, gives off no poisonous vapors, and costs for chemicals materially less than the cyanide costs in the previously used baths. The process has been in use over a year in a large American works and the following statement embodies the results of practical experience in the use and operation of the process. The Shimer liquid or melted bath consists of a mixture of easily fusible salts that do not possess case-hardening properties, into which is immersed fresh calcium eyanamid, which imparts to the bath case-hardening properties. The composition of the non-case-hardening salts appears rather immaterial. Good results have been obtained by using a mixture of sodium chloride, calcium chloride, and barium chloride in equal proportions by weight; also a mixture of one part sodium chloride

Jan 1, 1920

OFFICIAL INSTITUTE REPORTS FOR THE YEAR 1924 Report of the Secretary TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Directors of the A -I M. E, through their monthly meetings, a report of the year's progress is almost superfluous To the members who read the monthly reports of the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh infor¬mation, yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come The beginning of 1924 was not propitious for the members of the mining profession, though tonnage, production for 1923 had been high and the gross value higher than for several years The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed or were working in other industries Toward the end of the year, higher metal prices were in sight Old-time optimism began to grow, and it now brightens the outlook for 1925 An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing The number of new members joining has remained about as it was in 1922 and 1923 The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute

Jan 1, 1923

By Charles R. Fettke

The permeability of an oil or gas sand is its capacity for transmitting fluids, either liquids or gases, under pressure. The permeability of a sand depends upon the size and shape of the openings in it and the extent to which these communicate with one another, as well as upon the ratio of their volume to the total volume of the sand. The apparatus employed and the method of procedure used by the authors in conducting the permeability tests have been described in a previous pub1ication.l For the tests described here 1/2-in. cubes were used. They were set in the lower end of a 1-in. union, inserted in a square hole cut in a hard rubber stopper which fitted into the lower end of the union. In the tests with air, volumes were measured with a wet American gas meter of 100 cu. ft. capacity. In those with water, distilled water at room temperature was employed, unless otherwise noted. DescRiption of Sands Tested The tests described in this paper were performed upon 18 samples representing typical oil and gas sands from 7 localities in northwestern Pennsylvania. For purposes of identification, the cores from which the samples came have been designated by capital letters, the sequence of the samples in the cores by numerals, and the individual cubes by small letters. All cubes from the same samples came from adjacent portions parallel to the bedding. Core A of the Bradford sand came from the north central part of the Bradford field, from an area where water-flooding operations have proved highly successful. Core B of the same sand was obtained from the southern part of the field. This core contained a so-called "loose streak," 7.5 ft. thick, in the middle portion of which B2 is a representative sample. The "loose streak" has given trouble in water-flooding but responded favorably to an air-drive, using a pressure of 300 lb. The natural production was increased approximately five times over a period of three years in which the air-drive was in operation. Core C, also of the Brad-

Jan 1, 1931

By R. M. Caitlin

QUITE a number of years ago in looking for basic facts, it seemed obvious, in view of an unquestion-able supply of raw material and an extensive requirement probable in the near future, that the funda-mental requirement of any shale-oil industry was mass production 'by a continuous process. This decision greatly simplified matters, as it eliminated all considera-tion of externally-heated retorts, and all batch processes, which only utilize a part of the capacity of the interior space because, unless the ashes are removed as rapidly as formed, the space occupied by them is dead, instead of being occupied either by shale in active distillation or in drying out and heating up preparatory thereto. A second imperative and basic necessity soon appeared as a natural sequence, namely, the fixed carbon of the spent shale must be utilized to supply the heat for the eduction of the oil. PRODUCTION OF THE CRUDE As the production of the crude oil is the first and most important step in the utilization of oil-shale, being the only source from which the multitude of possible by-products can come, each by a special treatment of the crude oil, I will devote the time allotted to me to the subject of crude oil production-its cost expressed in terms of tons treated per man per shift. The costs of mining the shale and refining the crude shale oil vary with local conditions and are not specially influenced by the source of the crude. But the cost of distilling the shale in terms of tons per man shift seems to be the basis of any proper comparison of costs. After considerable experimenting, ranging from laboratory tests up to and including quantities of fifteen to twenty tons, it was evident that a plant might be made up of an indefinite number of units operating in concert. The economic size of the units, however, would .have to be determined by experiment. The general theory of our process contemplates a regulated combus-tion of the fixed carbon in the spent shale, in its incan-descent condition after all the oil has been driven out of it; and a transfer of the resultant heat to the mass of raw shale above.

Jan 1, 1927

THE Executive Board of The American Engineering Council met in Pittsburgh, May 26 and 27. Its actions on the licensing of engineers and on the Employment Bureau are printed at length elsewhere in this issue. The board announced plans purposing the solution of the national problems of water power and forestry, upon which "the industrial development of the nation and the standard of living of future generations largely depends. The whole Federal water-power situation is in so critical a condition that immediate constructive action by the Government to conserve the public interests, involving vast consequences of economic and Federal policy, is necessary. After a long discussion during which the water-power problem as it affects Government reorganization was reviewed and Henry Ford's Muscle Shoal's plan was discussed, the board decided to lay the entire question before President Harding. A national movement to conserve the nation's forests, in which engineers, the U. S. Forestry Service, the forestry services of the states, universities and technical schools, and other groups such as the farmers, the railroads, and lumbermen, shall pool their efforts, was set in motion by the engineers. The work will be in charge of a Reforestation Committee of the Council, headed by Charles H. MacDowell of Chicago. Mov-ing picture interests will be asked to aid. The board pledged its support to President Harding in his plan for Government reorganization. In adopting the report of its Committee on Public Affairs, headed by J. Parke Channing of New York, the Executive Board of the council determined, in the event of the failure of the President's efforts to bring about greater economy and ffieciency in national affairs by regrouping of Federal functions, to press independ-ently a nation-wide movement for the establishment of a Department of Public Works. Progress in a national survey of the two-shift day in American industries was reported by the Council's Committee on Work Periods in Continuous Industries. This survey, called the most extensive of its kind ever made, has been in progress for more than a year; and purposes an exposition of industrial conditions which shall form a basis for establishing the relative merits of three shifts of eight hours each and two shifts of twelve hours each.

Jan 7, 1922

By William B. Phillips

It is proposed in this paper to discuss some of the chemical and physical principles involved in the manufacture and use of this important by-product obtained in the manufacture of steel by the basic process. The name, " phosphate slag," is adopted as a sort of compromise between "Thomas slag" and "tetrabasic phosphate." By the first of these latter names, viz., " Thomas slag," it is known in Germany, Austria, France, and the other continental countries, and in England, and is more easily apprehended by those who have no special Knowledge of chemistry, while the name " tetrabasic phosphate," being descriptive of the nature of the slag, is perhaps the best. It is but seldom that a discovery of such moment to two great industries is to be chronicled in the history of technical science. On the one hand, the manufacture of iron and steel has been greatly benefited, while on the other hand, the effects already noticed, and still to follow, to the agriculturalist, are of scarcely less conseqnence. The great majority of iron ores in the world, perhaps 90 per cent. of then), are now available for the steel manufacturer, while the manufacturer, and more especially the consumer, of artificial manures is relieved from the fear of the exhaustion of the crude phosphates. We have in phosphate slag, therefore, a product of the highest importance to those who make and we steel and fertilizers. Two great industries, which heretofore have had but little in common, are thus brought into close connection with each other, and the results sure to follow, if one may judge from the history of the past ten years, cannot fail to be of great and increasing value. These results may be compared with those which followed the introduction of the cupriferous Spanish pyrites into England for the manufacture of sulphuric acid. The copper extracted greatly reduced the cost of the acid, hence that of artificial manures. Cheap manures meant better farming and cheaper farm products, and these meant better and cheaper living to nearly all classes of society. The amount of fertilizers now manufactured in the United States

Jan 1, 1889

By J. H. Wiggins

Granting that about 600,000,000 bbl. of light oil will be produced in the United States this year and taking the Bureau of Mines' statement that 71/2 per cent. of the total crude production will be lost before the finished gasoline is shipped from the refinery, the volumetric evaporation will be 45,000,000 bbl. of the cream of the gasoline. This is a ConseNative figure and is equivalent to 1,890,000,000 gal. The real value of this liquid is at least 150 per cent. of the value of an equal volume of motor fuel. At only 10 c. per gal., the value lost is $189,000,000; at 15 e. per gal. the loss is $283,000,000. If 750,000,000 bbl. of light and heavy oil are produced here this year and the average price per barrel is $1.333, the gross return to producers will be $1,000,000,000 and the net returns about $200,000,000, if the cost of production is only $1 per barrel. Thus, the evaporation bill is about 20 per cent. of the gross income and is equal to the net income of the crude-oil producers. Two other comparisons with popular phases of the petroleum industry will help give an adequate conception of the evaporation problem. These are: cost of preventing evaporation compared to cost of cracked gasoline and volume of gasoline evaporated compared to volume of gasoline manufactured from natural gas. When gasoline is manufactured from heavy oils by the cracking process, there are two important divisions of the total cost of the product: the manufacturing cost, such as plant cost, operation, maintenance, etc., and the cost of the barrel of heavy oil, from which the cracked gasoline is made. In preventing evaporation loss the cost first mentioned enters into the total cost, but the second cost is eliminated; that is, no charge is necessary for stock from which to manufacture the saving. A detailed analysis of these two costs on a large scale shows that the net income from a dollar spent in preventing evaporation loss from the lease through the refinery is twice the net income from a dollar spent in cracking. Of

Jan 1, 1924

The earliest record of coal in Indiana is one of the earliest in the country. At the close of the French and Indian War, in 1763, the famous Indian trader, George Croghan, was sent from Pittsburgh on a mission to the western Indians. His party met that of a hostile chief on the lower Ohio and was captured, and were taken up the Wabash River; on June 22nd, he passed the mouth of the Vermilion River-probably the Big Vermilion-and on June 23rd, he made the following entry in his journal: "on the South Side of the Ouabache runs a high hank, in which are several very fine coal mines, and behind this bank, is a very large meadow, clear for several miles."' The mines, of course, were outcrops. A few days after this he met some Indian acquaintances who secured his freedom. This location was at Ouicatanon, 210 miles from "Port Vincent," which was destroyed a few years later, and in what is now Fountain County, probably near Coal Creek. Croghan was familiar with the coal already being worked at Pittsburgh. Surveyors who ran the township and section lines in the first ten years of the last century noted the presence of coal and marked its position on the maps in 1804.2 The next record is by Nicholas J. Roosevelt, who in 1809 examined the Ohio and Mississippi Rivers prior to starting building the first steamboat to navigate these rivers. "Not only did he do this, but finding coal on the banks of the Ohio, he purchased and opened mines of the mineral; and so confident was he of the success of the project on hand, that he caused supplies of the fuel to be heaped upon the shore, in anticipation of the wants of a steamboat whose keel had yet to be laid."3 It is probable that this account confused the date of seeing the coal with that of mining it, as an earlier account by another relative of Mrs. Roosevelt of the first trip of the steamboat New Orleans in 1811 is as follows:

Jan 1, 1942

By George A. Johnson, Leon H. Banks

The Missouri-Kansas Zinc Corpn., operating in the Waco district, 15 miles northwest of .Joplin, Mo., owns large tailing piles made during milling operations of the years 1918-28 by the Butte-Kansas, Acme, and Barnsdall mining companies, whose holdings have been purchased and consolidated under the ownership of the Missouri-Kansas Zinc Corpn. These tailings had been considered too low in value to be worth retreating by the ordinary methods. C. Erb Wuensch, consulting engineer of the Missouri-Kansas Zinc Corpn., noted the difference in the type of tailing from upper-level and lower-level ore. The latter contained hard lime chats. He also found that mill losses had been due to particles of blende on the corners or sides of the chats and to the existence of soft, porous, cellular, lime chats containing varying amounts of blende. He conceived the idea that a quick grind in rolls or hall rnills might change the type of the rnaterial so that jigging could rnake a clean tailing for discard and a partly concentrated product sufficient in blende content to justify the expense of fine grinding in hall mills to free the mineral entirely. A laboratory was equipped with the necessary machines and the writers were assigned the problem of developing a method of retreating the tailings. Laboratory Testing From preliminary drill sampling of each pile was obtained the blende content, the soluble sulfate content, and the general characteristics of the material to he treated. The tailings were a mixture of lime and flint with some shale. Visual examination showed most of the blende to be in the dolomite and very little in the flint, although there were some flint particles with blende on the cleavages. The blende was found as particles on the corners or cleavage faces in one type of chat and in another disseminated in a soft, porous, cellular lime. Because of the porosity of the latter type of chat, the apparent specific gravity, under hindered-settling conditions, is less than that of a solid piece of lime or flint. That it,

Jan 1, 1930

By Richard S. Culver

In spite of the widespread interest in rock bolt research, relatively little is known about the critical region surrounding the bolt anchor. In analyzing the stress distribution around an opening resulting from rock bolt support, it is commonly assumed that the bolt is fixed at a point far enough from the surface so that the anchor does not influence the performance of the bolt. Furthermore, a bolt anchor is assumed to per- form satisfactorily if it will hold the design load with a minimum amount of load relaxation, commonly called bleedoff. From the standpoint of the design engineer both of these assumptions are reasonable, but they ignore the fact that the extremely high stresses in the region of the anchor are capable of generating fractures in the rock. Lang1 estimated the bearing stresses for a slot and wedge anchor on a one-inch-diameter bolt to be as high as 125,000 psi. This paper describes a more thorough analysis of the magnitude of the stresses around the anchor and the nature of the potential fractures that might result. It should be emphasized that there are two types of anchor-associated fracturing which may occur. The more common form, particularly in soft rock, is severe localized crushing of the rock in the immediate vicinity of the anchor, which makes securing the anchor difficult and causes bleed- off. It is also possible to develop larger single fractures which propagate out from the anchor, affecting the strength of the entire rock mass. The formation of these larger fractures is of primary concern in this paper. In addition to estimating the contact stresses and pullout load for slot and wedge bolt anchors, Lang carried out an important study of rock bolt interaction which served as a basis for the experimental phase of this investigation. In the first phase of his tests, a plate of photoelastic plastic was compressed by a row of piano wire bolts, simulating the interaction of bolt stress fields to form a zone of uniform compression (Fig 1). To show the supporting effect of this beam, hr carried out another test series

Jan 1, 1968

By C. W. Hill

FLUXES, in general, may be classified according to their use as soldering, foundry or casting, and metallurgical and the chemistry of their action follows quite closely this division. The term foundry or casting fluxes, as used here, refers to the substances added to molten metals, preparatory to casting into molds or ingots, with the object of removing small amounts of impurities that have been introduced in handling or melting the metal, which was placed in a fair state of purity by the previous refining or metallurgical processes. The sources of these impurities are the oxide coating on the surface of the ingots, material extracted or mechanically removed from the crucible or furnace wall, and those formed by the reaction of the molten metal with the heating gases or furnace atmosphere. As commonly used, the term fluxes is applied to such materials as ammonium chloride, zinc chloride, salt, borax, and boric oxide. A second class of materials, usually called deoxidizers, includes substances, such as metallic phosphides, sub-oxides, carbides, and bo-rides, that reduce the metallic oxides present in the metal. A third class includes various compounds that are molten and non-volatile at the temperature of the molten metal and are used primarily to protect the surface of the metal from the action of the furnace or exterior atmosphere; to this class belong such mixtures as lime and fluorspar, lime and soda ash, various minerals, etc. In some cases these protective layers may act in a manner similar to the metallurgical fluxes and dissolve or unite with the oxide impurities of the metal, but as generally employed this latter action is negligible since there is little opportunity for the coverings to come into contact with more than the surface of the metal, and hence they are without action on the body of the molten mass. The use of fluxes is the result of factory experience and tradition, but an extensive study has not been made of the chemical, and physical actions that occur or the effects of these actions on the properties of the metal. It would seem necessary in any successful study of metal fluxes

Jan 10, 1920

By W. B. Vietz, C. W. Hill, T. P. Thomas

FLUXES, in general, may be classified according to their use as soldering, foundry or casting, and metallurgical and the chemistry of their action follows quite closely this division. The term foundry or casting fluxes, as used here, refers to the substances added to molten metals, preparatory to casting into molds or ingots, with the object of removing small amounts of impurities that have been introduced in handling or melting the metal, which was placed in a fair state of purity by the previous refining or metallurgical processes. The sources of these impurities are the oxide coating on the surface of the ingots, material extracted or mechanically removed from the crucible or furnace wall, and those formed by the reaction of the molten metal with the heating gases or furnace atmosphere. As commonly used, the term fluxes is applied to such materials as ammonium chloride, zinc chloride, salt, borax, and boric oxide. A second class of materials, usually called deoxidizers, includes substances such as metallic phosphides, sub-oxides, carbides, and bo-rides, that reduce the metallic oxides present in the metal. A third class includes various compounds that arc molten and non-volatile at the temperature of the molten metal and are used primarily to protect the surface of the metal from the action of the furnace or exterior atmosphere; to this class belong such mixtures as lime and fluorspar, lime and soda ash, various minerals, etc. In some cases these protective layers may act in a manner similar to the metallurgical fluxes and dissolve or unite with the oxide impurities of the metal, but as generally employed this latter action is negligible since there is little opportunity for the coverings to come into contact with more than the surface of the metal, and hence they arc without action on the body of the molten mass. The use of fluxes is the result of factory experience and tradition, but an extensive study has not been made of the chemical and physical actions that occur or the effects of these actions on the properties of the metal. It would seem necessary in any successful study of metal fluxes to determine not only what impurities are present in metals melted under

Jan 1, 1921

ALTHOUGH the open-hearth charge contributes CO, C02, H2, A and water vapor to the combustion gases and absorbs oxygen from them, in the main the thermal effects in the melting charge and molten bath can be considered independently of those in fuel combustion; the latter then is regarded simply as the source of the net heat required to finish a heat of steel. First of all, it should be remembered that a large percentage of the heat supplied to the bath is furnished by oxidation of the various elements in the charge itself. If this charge consisted of 80 to 100 per cent of hot metal and the oxidation were accomplished by blowing in air or oxygen, as in the bessemer converter, the net heat absorption would be negative; that is, the bath would contribute part of the heat required to keep the melting chamber hot, in addition to that contained in the finished steel and slag. In actual open-hearth practices, probably the nearest approach to this is in the duplex furnace, charged with bessemer-blown metal and some hot metal, where very little heat is required to complete the refining and nearly all the heat energy from fuel combustion is used to keep the roof and walls of the melting chamber up to around 2900 to 3000 F (1600 to 1650 C), so that the bath will not cool off during the refining. The other extreme is with all-cold charges containing around 80 per cent steel scrap and 20 per cent cast iron or cold pig iron, in which case a very large proportion of the heat in the bath at tap is supplied from the fuel combustion. THERMAL EFFECTS IN MELTING In a typical heat, the fuel furnishes about four million British thermal units per ton of steel produced. The heat required, for the metallurgical processes is not easily defined in useful manner but it ranges downward from about one million Btu, depending not only on the charge but on the manner of calculation. In, any event, this requirement appears. small in comparison with the

Jan 1, 1964

THERE is probably no phase of basic open-hearth steelmaking that is more of an art and less of a science than mold and pouring practice. It varies widely from plant to plant; consequently it is obviously impossible to set down in detail in this chapter the many ramifications of practice that are now used. The discussion that follows therefore attempts only to give an outline of the more common methods, with examples sufficient to indicate some of the variations in procedure, and to emphasize a few of the many underlying problems that face the open-hearth operator at the pouring platform. MOLD DESIGN Ingot molds are hollow castings of considerable wall thickness. Despite this, non-uniformity in wall thickness should be strictly avoided to prevent the setting up of unnecessary stresses. Molds are cast in various forms, sizes, and shapes depending on the type of steel, and on whether the ingot is to be withdrawn from the mold or the mold from the ingot. The selection of ingot-mold material, which is usually cupola or blast-furnace iron containing approximately 3.5 per cent carbon, 1 per cent silicon, 0.9 per cent manganese, 0.2 per cent phosphorus, and 0.07 per cent sulphur, is governed by numerous considerations that affect mold life. (1) Factors in addition to wall thickness that should be given primary consideration at the foundry are casting skin, shrinkage stresses, and casting temperature. Factors in Mold Design. In use, mold thickness is of greatest importance, for it must be heavy enough to freeze the molten metal rising in the mold and to reduce the temperature of the steel below that of the melting point of cast iron to prevent the inner surface of the mold from melting, which would result in the welding of the ingot to the mold. The skin of an ingot, which solidities immediately upon contact with the relatively cold walls of the mold, must soon become thick enough to contract on the fluid mass and pull away slightly from the sides of the mold. The separation of the ingot from the mold depends entirely on the heat taken up by the mold from the steel.

Jan 1, 1944