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By John F. Sulzbach, Donald K. Walker, John F. Abel

With the increasing military significance of the arctic, the U.S. Army Corps of Engineers' ice- tunneling research program has been instituted to determine the feasibility of excavating large under- ice openings. Such openings would provide for year- around storage of material and housing of personnel, independent of surface weather conditions. This unique ice mining operation has been carried on in the tunnels at Camp Tuto, Greenland, during the summers of 1955, 1956, 1957 and 1958 by the U.S. Army Snow, Ice, and Permafrost Research Establishment (USA SIPRE), Wilmette, Ill. Supervisory personnel for the tunneling projects principally have been civilian mining engineers and mining engineering students from Colorado School of Mines. They have been employed under contract between USA SIPRE and the Denver Research Institute (DRI) of the University of Denver, Denver, Colo. Laborers have been enlisted military personnel attached to the U.S. Army Polar Research & Development Center (USA PR&DC) , Ft. Belvoir, Va.

Jan 6, 1959

Louis D. MILLS, San Francisco, Cal. (written discussion *).-The principle involved in the Crowe vacuum precipitation process is so elementary and the apparatus required is so simple, that the whole subject affords scant material for a technical discussion. As. one prominent Colorado metallurgist recently remarked when asked to contribute to this paper: "The Crowe process is the biggest step forward since the early clays of the cyanide process, but there is nothing to write about; just put it in your mill and try it." The writer confesses to a similar feeling, but having been closely identified with the process since its inception in 1916, he is perhaps in a position to at least comment on the theory involved and to record some of the results that have been achieved in actual practise. In practising the Crowe process, the solutions to be precipitated are first vacuumized in a suitable dispersion tower; that is, thin films of the liquid are subject to the action of a vacuum within a receiver. Sub-

Jan 1, 1919

By L. Alan Weakly

The first all-hydraulic drill introduced in the US began test drilling in a Missouri under round lead mine in mid-1973. Since that time, the hydraulic drill concept has slowly, and sometimes haltingly, come of age. Now, backed by impressive performance records and operator acceptance, hydraulic drills promise to produce a quantum leap in mining efficiency and, sometimes, major changes in mine and quarry engineering.

Jan 10, 1979

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 6 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and 6le this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. 11. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1941

By P. D. Merica

Certain compositions of the light, i:e., aluminum-rich, alloys of aluminum with magnesium and copper have become quite well known within the past ten years under the name of duralumin. These alloys are used for rolling and forging and can be so treated as to develop quite remarkable mechanical properties. Thus a properly heat-treated alloy containing about 4 per cent. of copper and about 0.5 per cent. of magnesium, rolled into sheet or rod, will have a tensile strength of approximately 55,000 lb. per sq. in. (3866 kg. per sq. cm.) with an elongation in 2 in. (50.8 mm:) of about 15 per cent. This alloy, duralumin, was developed by Wilm,1 and its properties more fully described by Cohn.2 The authors considered it worth while to investigate the mechanical possibilities of the light alloys of two somewhat analogous ternary series; namely, of aluminum-magnesium-nickel and of aluminum-magnesium-manganese, to study the effect of variation of composition upon mechanical properties within the alumimum-rich group of the aluminum-magne-

Jan 7, 1919

By H. B. Charmbury, D. R. Mitchell

Recovery of fine coal from solids reporting to wash water has become increasingly important. These solids range from about 28 mesh to 0 and constitute 3 to 7 pct by weight of the feed tonnage to a coal preparation plant. In the past they were usually wasted to streams, but present clean stream legislation makes it necessary to remove them from the wash water and, if economically possible, recover the associated coal as a saleable product. Where these solids are not wasted to streams or to slime ponds they are recovered by thickeners and filters. Since filter cake is often high in ash or sulfur, or both, it is not readily marketed or used. Common practice is to mix it with other plant products, generally slack or cleaned run-of-mine. Uniform blending is difficult, not only because the impurity is usually high, but also because during certain operating periods it is possible to get a concentration of this filter cake in a railroad or barge.

Jan 2, 1959

By Charles J. Lipton

Third World countries have lately taken a variety of actions to improve their revenues from the development of their mineral resources. Increasingly, their governments seek to negotiate production agreements on the basis of feasibility studies and discounted cash flow projections. Developing countries are now more selective in giving incentives to encourage investment in the mining sector. They recognize the value of their contributions to mining projects by way of guarantees and the provision of infrastructure. Third World governments now seek to participate in the basic decision making which determines profitability, such as loan-equity ratios, plant capacity, and processing and sales arrangements. They are alert to the benefits of large-scale development and appreciate their risks. They seek to increase their benefits from foreign exchange earnings and the multiplier effect of mining projects. New forms of arrangements are being used to insure that the mining sector is developed in harmony with the national objectives of the Third World.

Jan 1, 1977

By Paul C. Merritt

For more than 100 years, British Columbia has been considered a mountainous mining province, rich with potential but relatively poor in actual production. Times have changed. Today, Japanese interests and money have altered the difficult, if not once impossible, economic conditions and market factors which until recently precluded any great growth of the British Columbia mineral industry. The mining boom now underway in British Columbia has carried the total value of mineral production in the Province to a record height in 1962 as it rang up a 27% increase over that of 1961. Breaking the $200 million barrier for the first time, total value of British Columbia's mineral output reached $229- 276,385. Of this amount, metals accounted for 70%; industrial minerals, 6 %; structural materials, 9 %; and fuels, 15%. The substantial increase is attributed to the record production of copper, iron, asbestos, natural gas and petroleum, in addition to the continuing high production rate and favorable prices of other mineral commodities.

Jan 12, 1963

By William Kent

More than twelve years were spent by Wöhler at the instance of the Prussian Government in experimenting upon the resistance of iron and steel to repeated stresses. The results of his experiments are expressed in what is known as Wöhler's law, which is given in the following words in Du Bois's translation of Weyrauch:* " Rupture may be caused not only by a steady load which exceeds the carrying strength, but also by repeated applications of stresses, none of which are equal to the carrying strength. The differences of these stresses are measures of the disturbance of continuity, in so far as by their increase the minimum stress which is still necessary for rupture diminishes." A practical illustration of the meaning of the first portion of this law may be given thus: If 50,000 pounds once applied will just break a bar of iron or steel, a stress very much less than 50,000 pounds will break it if sufficiently often repeated. This is fully confirmed by the experiments of Fairbairn and Spangenberg, as well as by those of Wöhler; and, as is remarked by Weyrauch, it may be considered as a long-known result of common experience. It partially accounts for what Mr. Holley has called the " intrinsically ridiculous factor of safety of six." Another "long-known result of experience"—although this has not, as the writer believes, been investigated by scientific experimenters—is the fact that rupture may be caused by a succession of shocks or impacts, none of which alone would be sufficient to cause it. Wrought iron will crystallize by repeated blows in service and become weaker than cast iron. Iron axles, the piston-rods of steamhammers, and other pieces of metal subject to continuously repeated shocks invariably break after a certain length of service. They have a "life" which is limited. Iron rods in bridges sometimes crystallize and break, although the rods in most of our iron bridges

Jan 1, 1880

By C. E. Arnold

IN attacking the problems of mining and treating large disseminated copper orebodies such as those occurring in the Miami or the Ray district of Arizona, one of the vital questions to be decided is, "What is the value of the orebody per ton in place?", The importance of this question lies in the fact that its answer helps to reach a decision concerning the method of mining to be employed. Let it be assumed for the moment that milling and smelting practice, especially the latter, is more or less standardized; and has a cost incapable of much variation, while the cost of mining has a considerable range owing to the large number of mining methods by which a mine may be exploited. For instance, a method may be adopted whereby all the available ore can be extracted perfectly clean (i.e., unmixed with barren material) at a relatively high cost; or a method may be used involving the necessary dilution of a portion of the ore with waste, in order to recover that portion, thus giving a relatively poorer extraction but nevertheless a lower working cost than the former method. Naturally, between these two extremes there lie intermediate methods. In order to arrive at a solution of a mining method problem that is of any value, it is necessary that accurate and complete estimates of mining, milling, and smelting performances and costs shall be established. By way of illustration is given a, case of mining, by the system of undercutting and caving, a large orebody with an average content of 1.50 per cent. copper supposedly all in sulphide form, to which case has been applied those results in mining operations which one may fairly assume are to be expected when viewed in the light of G. R. Lehman's ore-drawing experiments, which form the subject of a paper to be presented at this meeting. It is assumed that the total. costs will be as shown in the following table:

Jan 9, 1916

By W. F. Hosford

A series of aluminum single crystals was subjected to axially symmetric flow by drawing through dies. The orientation dependence of the drawing stress, which indicates the resistance to this type of flow, compares reasonably with predictions of Taylor and of Bishop and Hill. Measured lattice rotations likewise are generally consistent with theory. The most successful analyses of the plastic behavior of polycrystalline metal and its relationship to single crystal behavior are those of Taylor1-3 and of Bishop and Hill.4-6 The purpose of this paper is to provide a critical test of some of the basic assumptions involved in these theories. Both treatments apply to fcc metals and assume the shape change of each grain in a polycrystal to be the same as that of the polycrystal as a whole. Thus for a randomly oriented polycrystal extended under uni-axial tension each grain is assumed to undergo axially symmetric flow. dey = dez = -1/2dex, deyZ = dezx = dexy = 0 [l] where x, y, and z are a set of orthogonal axes, x being the tensile axis. Although [011.] oriented grains in bcc and fcc metals may depart markedly from this ideal behavior,7,8 the assumption is probably quite reasonable for most grains. Under a uniaxial tensile stress, ox, the work dW per unit volume expended in producing an increment of axial strain dex is, dW=oxdex [21 Since this work is expended in slip, dw =STi dyi 131 where Ti and yi are the shear stress and shear strain on the active slip systems. In both analyses Ti is taken to be the same on all slip systems, and dependent only on the total prior shear strain on all systems, so dw = Tdy [41 where t is the shear stress required for slip and y is the sum of the shear strain yi on all slip systems. Combining 121 and [4] and defining M = oX/T The ratio M is a generalized Schmid factor. It relates the tensile stress required for axially symmetric flow, ox, to the basic shear stress, 7, and it also expresses the ratio of crystallographic strain, y, to the tensile strain, Ex It depends only on the orientation of the crystal. Taylor evaluated M for various orientations by finding the least value of dy/dEx which could satisfy the shape change. Bishop and Hill, on the other hand, found M by considering the relative work (1/T)dW/dEx expended by stress states which could activate enough slip systems to produce the shape changes. The results of both methods appear to be equivalent, although certain omissions were made in Taylor's original work. The orientation dependence of M, calculated by the second method,9 is shown in Fig. 1. Taylor used the average 2= 3.06 for all possible orientations to predict the tensile stress-strain curve (oxvs Ex) for a random polycrystal from the shear stress-strain curve (t vs y) of a single crystal. Changes in M from lattice rotation were neglected so points on the ox vs ex curve were simply taken at ox = 3.06t and e = y/3.06 from corresponding points on the t vs y curve. Recent extension of the analyses of Taylor and of Bishop and Hill to crystallographically textured metals has been used to relate plastic anisotropy to textures, and to predict the potential texture hardening that could result from texture control.9 Unfortunately there have been relatively few experimental tests of the underlying theory. Taylor found that the tensile stress-strain curve of polycrystalline aluminum did agree reasonably well with that predicted from a single-crystal T-y curve. Had the single crystal undergone easy glide, how-

Jan 1, 1965

By M. Karmis

The development of engineering rock classification systems has received considerable at tent ion during the past few years. The purpose, application and method of assigning an index of rock quality, vary considerably between these systems. Several of them are directed toward the assessment of stability and support potential of an excavation whereas other systems are estimating a particular response of the rock, i.e. blastability or ripability. In the most widely accepted engineering rock classification systems, rock quality is expressed either in terms of meaningful descriptions or by a quantitative evaluation of a geomechanical property or properties. The application of sonic wave parameters in the engineering classification of rock mass and rock material has been the subject of considerable interest amongst investigators. The advantages of utilizing such techniques include minimal sample preparation, capabilities for large scale testing and the ability to perform non- destructive as well as reproducible tests. The purpose of the research presented in this paper was to determine the most appropriate sonic wave parameters for engineering rock classification purposes, to utilize these findings in developing new or modifying existing classification systems and, finally, to apply this information in the prediction and analysis of blasting wave characteristics.

Jan 1, 1984

Jan 1, 1923

Jan 1, 1923

By William Bent

MORE than twelve years were spent by Wöhler at the instance of the Prussian Government in experimenting upon the resistance of iron and steel to repeated stresses. The results of his experiments are expressed in what is known as Wöhler's law, which is given in the following words in Du Bois's translation of Weyrauch :* "Rupture may be caused not only by a steady load which exceeds the carrying strength, but also by repeated applications of stresses, none of which are equal to the carrying strength. The differences of these stresses are measures of the disturbance of continuity, in so far as by their increase the minimum stress which is still necessary for rupture diminishes." A practical illustration of the meaning of the first portion of this law may be given thus : If 50,000 pounds once applied will just break a bar of iron or steel, a stress very much less than 50,000 pounds will break it if sufficiently often repeated. This is fully confirmed by the experiments of Fairbairn and Spangenberg, us well as by those of Wöhler; and, as is remarked by Weyrauch, it may be considered as a long-known result of common experience. It partially accounts for what Mr. Holley has called the "intrinsically ridiculous factor of safety of six." Another "long-known result of experience "-although this has not, as the writer believes, been investigated by scientific experimenters-is the fact that rupture may be caused by a succession of shocks or impacts, none of which alone would be sufficient to cause it. Wrought iron will crystallize by repeated blows in service and become weaker than cast iron. Iron axles, the piston-rods of steam-hammers, and other pieces of metal subject to continuously repeated shocks invariably break after a certain length of service. They have a " life" which is limited. Iron rods in bridges sometimes crystallize and break, although the rods in most of our iron bridges * Strength and Determination of Dimensions of Structures. By Dr. J. J. Weyrauch. Translated by Du Bois, New York, 1877.

Jan 1, 1880

By John Birkinbine

An item of considerable importance to the producers of pig-iron is the disposition of the slag or cinder from the blast-furnace; and various plans have been adopted at different works to care for the rapid accumulation of this generally waste material. The charge per ton of iron made which must be allowed for the care of cinder is sufficient in times of business depression to give plants having facilities for disposing of their slags an advantage over others less favorably arranged, and to allow iron to be produced profitably in the one case and prevent a profit in the other. The varied methods employed and the means of conveyance utilized need not be detailed. It is sufficient to say that the large outputs of American blast-furnaces, and consequent rapidly augmenting dump-piles, have brought into general favor the use of cars carrying the slag in a liquid condition. The advantages of this method are the prompt removal of the slag, the reduced space occupied by the dump-piles, and the facility of converting the slag into such forms for use as may be desired. The progress in iron-manufactlire is also marked by a more general adoption of methods by which molten metal is carried in vessels away from the point of its production; and, anticipating the prospective advance in pig-iron manufacture, it does not seem unreasonable to prophesy the early abolition of casting-houses at blastfurnaces, particularly where several are grouped together; or the casting of steel ingots away from the converters or furnaces. In some large blast-furnace plants, the iron is carried molten from the blast-furnaces to the converters or other furnaces. Even where it is cast into pigs, casting-sheds removed from the immediate vicinity of the furnace-stack would, perhaps, be superior to casting in beds in front of the furnaces. The idea of casting-sheds appears to present the following advantages : 1st. The equipment of boilers, hot-ovens, and blowing-machinery could be closely grouped around the blast-furnace stacks, permitting

Jan 1, 1887

By Ralph V. Higgins

This paper concerns the magnitude of the amount of supersaturation that occurs in an underground reservoir during the flow of oil and gas to wells and to the amount of undersaturation that occurs during repres-suring of an oil reservoir where some effective permeability to gas exists. The study is based on earlier laboratory findings of other investigators on the rate of diffusion of gas in oil as a function of the depth of oil. Utilizing these relationships and the principles of reservoir mechanics, a quantitative estimate of undersaturation and super-saturation was calculated. The results showed that the diffusion of the gas is rapid enough that for all practical purposes no supersaturation exists during the flow of oil to wells or undersaturation during repressuring in reservoir sands having some effective permeability to gas. The reason diffusion of the gas virtually keeps the oil saturated is the long time required in radial flow for oil to reach the well and the slow rate at which pressure in reservoirs is increased during repressuring. INTRODUCTION Knowledge of the phase relationships during flow of gas and oil in an underground reservoir is essential to operating the reservoir in the most efficient manner. In material-balance calculations and in fluid-flow studies, the oil is assumed to contain all the gas that it will dissolve at given temperature and pressure. Pressure-volume-temperature relationships are normally obtained in the laboratory using "bottom-hole" or combined samples of the reservoir fluids. In such laboratory determinations equilibrium is obtained between the oil and gas in the pressure cells by mechanical agitation. During the flow of oil and gas in reservoirs, however, no comparable agitation occurs to mix thoroughly these fluids to aid in effecting equilibrium between the two phases. During repressuring of a partly depleted underground reservoir, the gas is usually injected into the reservoir faster than the oil can absorb it; consequently, the oil is undersaturated. On the other hand, as the oil flows through the reservoir to the wells during producing operations the pressure decreases faster than the gas in solution can diffuse through the oil to the gas phase. The oil therefore is supersaturated with gas. Where the oil is undersaturated, gas diffuses away from the gas-oil interface, and where it is supersaturated the gas diffuses toward the interface. In either case the gas moves from a higher to a lower saturation. This report contains the results of a study of the factors influencing the degree of nonequilibrium of the phase relations of oil and gas in porous mediums during the flow of oil through reservoirs to wells and also during the injection of gas into partially depleted sands. Data from an underground reservoir are presented and the degree of supersaturation during the flow of the oil through the reservoir to the well is approximated. Also data from another reservoir are used and the degree of undersaturation during the repressuring operation is calculated. In addition, the flow rates of oil in laboratory experiments and in underground reservoirs are compared, as data from the laboratory are often used to interpret events in the reservoir, and the rates of flow influence appreciably the degree of nonequilibrium. Much of the contents of this report was prepared in 1943; but, because of other activities during and since the war, the manuscript was left untouched until 1952, when it was decided to include an estimate of the amount of undersaturation during repressuring as well as supersaturation during flow.

Jan 1, 1955

By N. J. Grant, W. R. Opie

THE amount of hydrogen that will dissolve in lead has been considered negligible. However, a limited number of measurements made recently using apparatus built for determining hydrogen solubility in aluminum alloys' indicate that liquid lead will hold a small but appreciable amount of hydrogen in solution. The apparatus used was similar to that developed by Sieverts.' This consists of a bulb to hold the molten metal, a gas burette for introducing a measured quantity of gas into the bulb and a manometer for measuring the gas pressure in the bulb. Measurements are made by introducing enough of an insoluble gas (helium) to fill the system at a given temperature and pressure, thereby determining the hot volume of the bulb. This gas then is pumped out and hydrogen is introduced until the same pressure is reached, the metal being maintained at the same temperature while in contact with each gas. The difference between the volumes corrected for pressure is then the hydrogen solubility. A more detailed account of the procedure can be found in refs. 1 and 2. The lead was melted in an alundum crucible by induction heating to provide uniform temperature and an important stirring effect. The metal was the purest obtainable, 99.999 + , prepared especially by the research department of the American Smelting and Refining Co. Measurements were made by approaching the equilibrium value from high and low temperatures during the constant pressure runs, and from high and low pressures when the temperature was held constant. Thus a number of measurements were made on each of two large samples which weighed 336 and 398 g. The gases were purified as .described in ref. 1. The effect of temperature on the solubility was studied with the pressure held constant at 760 mm of Hg. To show the effect of pressure, solubility measurements were taken at two constant temperatures, 600" and 900°C. Results The effect of temperature on hydrogen solubility is shown in Fig. 1. The curve representing the data is parabolic, as are plots of hydrogen solubility vs. temperature for other metals and alloys (aluminum,' copper," and iron,& for example). Fig. 2 shows the relationship that exists when the solubility is

Jan 1, 1952

By L. G. Graper, E. L. Ramsey

The present program of increased production of armament and lend-lease material for mechanized war has created a problem for the shops that must do the machining. They have naturally turned to the steel producers to provide them with a steel that can be accurately machined with the greatest possible speed. The adding of sulphur to steel as an aid to machinability has long been practiced; however, it may cause red shortness in rolling and may result in billets with seams and cracks, which must be removed before rolling can be continued. This conditioning of billets slows down production and adds to the cost of making steel. Experience with various grades of sulphur steel made to different specifications has shown that Bessemer sulphur steels roll better than similar grades made in the open hearth, and also that low-carbon steels that are open or semikilled as tapped roll better than completely deoxidized or killed steels. This has led to the belief that oxygen plays an important part in the rolling qualities of sulphur-bearing steels. It is generally held that the red shortness of sulphur steels is due to the low melting point of the sulphide compounds that separate out at the grain boundaries when the steel solidifies. At the rolling temperature of steel these sulphide compounds melt and cause cracking. Adding Sulphur as a Sulphite These difficulties can be avoided if sulphur is introduced into the stecl by means of an anhydrous sulphite, such as sodium sulphite or sodium bisulphite, which—upon decomposition—forms sulphur dioxide. It is assumed that, in this case, the oxygen of the sulphur dioxide forms part of the sulphide inclusions in the steel, and raises their solidification temperature enough so that the formation in the steel of a low-melting eutectic is prevented. The result is the prevention of hot shortness and a more uniform distribution of inclusions. Fig. I shows photomicrographs of steels made with sulphur, while Fig. 2 illustrates the structure of steels made with sodium bisulphite. These samples were cut from the steels as cast—that is, before rolling— and were polished and lightly etched to bring out the grain boundaries. Fig. I shows that sulphide inclusions segregate more or less at the grain boundaries, and it can be seen how the continuity of these low-melting inclusions would cause red shortness. Fig. 2 shows that the sulphide inclusions arc more or less uniformly distributed throughout the matrix. This arrangement of inclusions has no apparent effect on the rolling qualities of a steel. This statement has been substantiated by the observation of the rolling of over 6000 tons of steel made with a sulphite addition. Results As stated before, the sulphur dioxide is added to steel by means of the decomposi- 27

Jan 1, 1942

By L. G. Graper, E. L. Ramsey

The present program of increased production of armament and lend-lease material for mechanized war has created a problem for the shops that must do the machining. They have naturally turned to the steel producers to provide them with a steel that can be accurately machined with the greatest possible speed. The adding of sulphur to steel as an aid to machinability has long been practiced; however, it may cause red shortness in rolling and may result in billets with seams and cracks, which must be removed before rolling can be continued. This conditioning of billets slows down production and adds to the cost of making steel. Experience with various grades of sulphur steel made to different specifications has shown that Bessemer sulphur steels roll better than similar grades made in the open hearth, and also that low-carbon steels that are open or semikilled as tapped roll better than completely deoxidized or killed steels. This has led to the belief that oxygen plays an important part in the rolling qualities of sulphur-bearing steels. It is generally held that the red shortness of sulphur steels is due to the low melting point of the sulphide compounds that separate out at the grain boundaries when the steel solidifies. At the rolling temperature of steel these sulphide compounds melt and cause cracking. Adding Sulphur as a Sulphite These difficulties can be avoided if sulphur is introduced into the stecl by means of an anhydrous sulphite, such as sodium sulphite or sodium bisulphite, which—upon decomposition—forms sulphur dioxide. It is assumed that, in this case, the oxygen of the sulphur dioxide forms part of the sulphide inclusions in the steel, and raises their solidification temperature enough so that the formation in the steel of a low-melting eutectic is prevented. The result is the prevention of hot shortness and a more uniform distribution of inclusions. Fig. I shows photomicrographs of steels made with sulphur, while Fig. 2 illustrates the structure of steels made with sodium bisulphite. These samples were cut from the steels as cast—that is, before rolling— and were polished and lightly etched to bring out the grain boundaries. Fig. I shows that sulphide inclusions segregate more or less at the grain boundaries, and it can be seen how the continuity of these low-melting inclusions would cause red shortness. Fig. 2 shows that the sulphide inclusions arc more or less uniformly distributed throughout the matrix. This arrangement of inclusions has no apparent effect on the rolling qualities of a steel. This statement has been substantiated by the observation of the rolling of over 6000 tons of steel made with a sulphite addition. Results As stated before, the sulphur dioxide is added to steel by means of the decomposi- 27

Jan 1, 1942