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By C. P. Sandberg

Having been occupied in inspecting and testing iron and steel these twenty years in England, and previous to that having served on the Board of Iron Masters in Sweden, I have naturally been very much interested in the subject of the use of steel for structures. I regret that I can offer but comparatively small experience on that had, having had principally to do with steel for railway plant and rails, but granting these to be a kind of "structure," and also that steel for rails has similar duties to perform in many respects, and is generally manufactured in the same way and at the same works as steel for stuctures, properly speaking, I may be entitled to offer an opinion on the use of steel in construction. In a paper recently presented to the Institution of Civil Engineers in London, Mr. Ewing Matheson has recommended that the Board of Trade rules should be amended so as to allow of a maximum straining of 8 tolls per square inch instead of 6 1/2 tons. But it is equally necessary to fix the amount of ductility or elongation of the metal for such a strain as 8 tons. Strength and ductility should always be spoken of together. Mr. Matheson says that steel can be manipulated in the factory in the same way and with the same tools as are used for iron. This can only be granted for mild steel; for hard steel would be spoilt by the rough mechanical treatment which iron can stand, such as punch ing, for instance; and the remedy for regaining the strength lost by punching hard steel, viz., annealing, cannot always be applied. Noth ing proves this fact better than the punching of steel rails of consid erable hardness, which caused fractures at an early period of steelunaking, and which resulted in the stipulation for drilling instead of punching the bolt-holes, which had been formerly applied to iron rails without any damage. In fact commissions to establish standard tests are now working on the Continent, principally in Germany, where

Jan 1, 1882

By John Lohrenz

Consider an investor who, knowing future costs and revenues, can choose how rapidly to produce from a given mineral source. If the investor elects to make that choice to maximize present value of future profits, how do policies affect the choice? Various alternative policies are examined. Some, such as higher royalty rates, lead to slower production rates than would otherwise obtain. Clearly, the chosen rates of production are policy-dependent. One is wisely counseled to consider how mineral policies affect the rate of production from given sources when analyzing current and alternative policies.

Jan 1, 1982

By Leslie W. Austen

ROTARY kiln operators will agree that some of the most severe conditions a refractory must stand occur in the hot zone of a kiln burning Portland cement, dead burn dolomite, magnesite, peri-clase, and similar materials. Frequently the operator is faced with factors beyond his control which drastically shorten the life of refractories. Shutdown due to mechanical failure can be serious if the period is of sufficiently long duration to cause the dropping of coating or the loosening of the lining. A change in slurry can affect the coating and cause ring buildup. A change in type of fuel and its effect upon the flame can cause a shift in location of the hottest zone. Weekend shutdowns or any other interruption can cause the operator trouble and may damage the refractories, since stopping and starting a rotary kiln is certainly more difficult than stopping and starting a motor. Some operators have tried to set an estimate of damage for each shutdown in equivalent days of running time. Conditions affecting the refractory may be roughly grouped in four classes: chemical attack, mechanical stress, thermal shock, and abrasion. Chemical Attack: The drive to obtain maximum production through a kiln demands maximum operating temperatures, temperatures which are limited more by the ringing up or melting of the clinker. This can cause interface temperatures at the junction of coating and refractory which require the use of a basic kiln block to withstand the chemical attack. Chemical changes take place within the refractory itself, especially in chemically bonded or unburned kiln blocks. These changes cause the formation of the ceramic or burned bond. Migrating liquids or fluxes from the kiln charge have an effect within the refractory and lead to mineral or glass formation. The alkalies, sodium and potassium, migrate into the refractory as silicates, chlorides, sulphates or other salts. They may move under capillary action or may be caused to move by volatilization with condensation in the cooler portion. Mechanical Stress: Concentrated stress may be caused by several factors or combinations thereof. I—The rings of refractories must be kept tight and rigid within the kiln, and this alone demands considerable force to hold the blocks in place. So that the force will not be concentrated, the blocks should fit the circle as perfectly as possible, with the faces in contact overall. 2—As the kiln is heated, thermal expansion takes place at the hot end of the kiln block. Since this disturbs the plane face it too can cause a concentrated stress at the two ends of the block, and shearing stress can be set up within the brick itself because of the difference in expansion between the two ends. 3—If a lining becomes loose and moves in the shell very severe stress can be set up, and as the kiln rotates this load changes and gives the effect of repeated loading. Permanent expansion of the refractory can also cause severe loading. 4—Not least important, flexing of the kiln is frequently the cause of concentrated stresses. Thermal Shock: Thermal shock, the result of heating and cooling too rapidly, occurs on starting and stopping or when a large patch of coating drops, exposing the bricks. Again, its destructive effect is often the result of phase change, liquid to solid or the reverse; dense refractories loaded with glass-forming impurities are particularly susceptible. Thermal shock is a. problem with refractories set in the wall or roof of a stationary furnace, and becomes even more serious in a rotary kiln, the tendency to spa11 being magnified with movement and concentration of stress. Uniform rate of feed and loading insures both better coating and a more uniform stress. Abrasion: If the refractories do not take a coating, abrasion can become a most destructive factor. Movement of the lining in shell or movement of loose blocks causes abrasion, which is also most destructive if the refractories do not take a coating. An analysis of the problem of basic lining for the hot zone reveals, therefore, a number of desirable characteristics: high refractoriness, basic chemical reaction, resistance to spalling, good strength at all stages, ability to take coating, true sizing, volume stability, and abrasion resistance. Increased demand

Jan 1, 1953

By Leslie W. Austen

ROTARY kiln operators will agree that some of the most severe conditions a refractory must stand occur in the hot zone of a kiln burning Portland cement, dead burn dolomite, magnesite, peri-clase, and similar materials. Frequently the operator is faced with factors beyond his control which drastically shorten the life of refractories. Shutdown due to mechanical failure can be serious if the period is of sufficiently long duration to cause the dropping of coating or the loosening of the lining. A change in slurry can affect the coating and cause ring buildup. A change in type of fuel and its effect upon the flame can cause a shift in location of the hottest zone. Weekend shutdowns or any other interruption can cause the operator trouble and may damage the refractories, since stopping and starting a rotary kiln is certainly more difficult than stopping and starting a motor. Some operators have tried to set an estimate of damage for each shutdown in equivalent days of running time. Conditions affecting the refractory may be roughly grouped in four classes: chemical attack, mechanical stress, thermal shock, and abrasion. Chemical Attack: The drive to obtain maximum production through a kiln demands maximum operating temperatures, temperatures which are limited more by the ringing up or melting of the clinker. This can cause interface temperatures at the junction of coating and refractory which require the use of a basic kiln block to withstand the chemical attack. Chemical changes take place within the refractory itself, especially in chemically bonded or unburned kiln blocks. These changes cause the formation of the ceramic or burned bond. Migrating liquids or fluxes from the kiln charge have an effect within the refractory and lead to mineral or glass formation. The alkalies, sodium and potassium, migrate into the refractory as silicates, chlorides, sulphates or other salts. They may move under capillary action or may be caused to move by volatilization with condensation in the cooler portion. Mechanical Stress: Concentrated stress may be caused by several factors or combinations thereof. I—The rings of refractories must be kept tight and rigid within the kiln, and this alone demands considerable force to hold the blocks in place. So that the force will not be concentrated, the blocks should fit the circle as perfectly as possible, with the faces in contact overall. 2—As the kiln is heated, thermal expansion takes place at the hot end of the kiln block. Since this disturbs the plane face it too can cause a concentrated stress at the two ends of the block, and shearing stress can be set up within the brick itself because of the difference in expansion between the two ends. 3—If a lining becomes loose and moves in the shell very severe stress can be set up, and as the kiln rotates this load changes and gives the effect of repeated loading. Permanent expansion of the refractory can also cause severe loading. 4—Not least important, flexing of the kiln is frequently the cause of concentrated stresses. Thermal Shock: Thermal shock, the result of heating and cooling too rapidly, occurs on starting and stopping or when a large patch of coating drops, exposing the bricks. Again, its destructive effect is often the result of phase change, liquid to solid or the reverse; dense refractories loaded with glass-forming impurities are particularly susceptible. Thermal shock is a. problem with refractories set in the wall or roof of a stationary furnace, and becomes even more serious in a rotary kiln, the tendency to spa11 being magnified with movement and concentration of stress. Uniform rate of feed and loading insures both better coating and a more uniform stress. Abrasion: If the refractories do not take a coating, abrasion can become a most destructive factor. Movement of the lining in shell or movement of loose blocks causes abrasion, which is also most destructive if the refractories do not take a coating. An analysis of the problem of basic lining for the hot zone reveals, therefore, a number of desirable characteristics: high refractoriness, basic chemical reaction, resistance to spalling, good strength at all stages, ability to take coating, true sizing, volume stability, and abrasion resistance. Increased demand

Jan 1, 1953

By Leendert de Witte

Conventional resistivity logs consisting of a short normal, a long normal, and one or more long lateral curves do not give data that allow a complete quantitative interpretation in beds thinner than 20 ft. Reservoir rocks usually exhibit zones of continuous homogeneity of quite limited thickness where the long lateral curves become useless because of adjacent bed effects and boundary phenomena. If the beds are 12 ft or thicker, the short and long normals may be used for qualitative interpretation, which can be streamlined by the application of simplified departure curves. For beds of a thickness less than twice the long normal spacing, this procedure breaks down. The combination of the limestone curve, the later-olog or guard electrode log, and the microlaterolog permit quantitative interpretation for beds that are at least 10 ft thick, provided the mud resistivity and the hole diameter are known with sufficient accuracy. For beds thinner than 10 ft, combinations of the microlaterolog with short spaced laterologs and pseudo laterologs appear to be promising. Interpretation of these curves again requires the application of simplified departure curves. Resolution of various possible combinations was analyzed using departure curve data calculated on the Whirlwind I computer at the Massachusetts Institute of Technology. A field example is shown using the microlaterolog-microlog combination, and the combination of a 6-in. modified laterolog plus a 6-in. pseudo laterolog. INTRODUCTION For the purpose of quantitative interpretation of resistivity logs in porous formations, we want to obtain two essential quantities from the logs, namely, the true resistivity of the undisturbed formation, Rt, and the resistivity of the part of the formation invaded by mud filtrate, Rt. The apparent resistivities of all conventional logging devices are functions of these two parameters and are also influenced by a third unknown parameter, the diameter of the invaded zone, d. It has been shown' that from the normal curves alone it is impossible to arrive at a unique solution for the three unknowns, Rt, R1, and d1. In very thick homogeneous beds, if invasion is not too deep, we can obtain a fair approximation to Rt from the long lateral curves and then use the two normal curves to find Rt and d1 Even under the most favorable conditions, the resolution of this system is not very good. The short normal does not give a reasonable approximation to R1 unless invasion is very deep (dl>16 hole diameters). For very deep invasion, however, the long laterals no longer approximate Rt. For bed thickness between 20 and 40 ft, the long laterals are affected appreciably by the adjacent beds; and the curves are distorted by boundary anomalies to the extent that they lose their quantitative usefulness in most cases. For the same bed thicknesses, the normal curves still function reasonably well. Although it is impossible to find unique solutions Lor R1 and Rt using the normal curves alone, we can obtain a reasonable approximation for the ratio R1/Rt through the use of simplified departure curves. This fact was brought to our attention by A. J. de Witte, geologist with Continental Oil Co. As the magnitude of Rl/Rt is a major clue to the presence of oil in formations, this method can be used to good advantage for qualitative analysis and will be discussed in somewhat greater detail. With the aid of suitable bed thickness corrections, the analysis of the normal curves may be used for bed thicknesses larger than 12 ft. For thinner beds, the method rapidly loses its resolution; and we have to resort to different types of resistivity logs if we want to attempt to analyze the curves quantitatively. The inadequacy of conventional resistivity curves in thin beds is far more serious than generally realized. Fig. 1 shows a conventional E. S. with a 16-in. and 64-in. normal and a 16-ft lateral through a section of Lansing-Kansas City lime, in comparison to a guard electrode survey through the same section in a neighboring well. The porous zones, which show up as low resistivity breaks on the guard electrode log, are completely masked by adjacent bed effects and boundary anomalies on the conventional curves. Even the short normal shows most of the porous Zones only as Vague deflections and in many cases fails to register Their

Jan 1, 1955

By P. E. Busby, C. Wells

FURTHER study of data used in determinations of 1—rates of diffusion of boron in austenite and 2—solubilities of boron in the a and phases of iron and steel' has provided an equation for the diffusion of boron in a iron. In brief, the previously published data were accumulated from the results of deboron-izing (and decarburizing) experiments carried out in the range of 700° to 1300°C. Diffusion coefficients (D?) for boron in austenite were calculated using the Grube solution of Fick's law. However, only solubility values were estimated from the discontinuous concentration-penetration curves, Fig. 1, which are characteristic of diffusion in two phases. Dr. Carl Wagner' has recently provided a solution for calculating D values from penetration curves of this type as follows: Cl1.1 —C8/C8- C11.1 = vp ? e ? erf (?) and D = ?/4?2 t where C11,12, C8, C11, and E have the values shown in Fig. 1. D is the diffusion coefficient, sq cm per sec; t is time of deboronizing anneal, see; and ? is a di-mensionless parameter. For a given diffusion experiment, the value of ? can be readily obtained by graphical solution from a plot of y vs the right-hand part of Eq. 1. D may then be evaluated from Eq. 2. The avplication of this solution to previously re-ported results, of which excerpts are given in Table I, permits the calculation of diffusion coefficients for boron in a iron. On the basis of these meager data, it is tentatively concluded that the diffusion of boron in a may be represented by the equation Da = 1011 e-92,900/RT where R is the gas constant, cal X 0C-1 X mol-1; and T is the absolute temperature, OK. Although the frequency factor, 106 sq cm per sec, is admittedly several orders of magnitude higher than expected, the value of Q, 62,000 cal per mol, appears reasonable and is, in fact, very similar to that for the self-diffusion of iron. It is pertinent to mention at this point that the value of Q obtained for the diffusion of boron in austenite by means of the Wagner solution is 19,000 cal per mol and is in excellent agreement with the value previously reported1 in the equation DT = 2xl0-3 e-21,000/RT [4] which was determined by the application of the Grube solution to other data. The fact that determined constants A and Q in the equation D? = A e-Q/RT were practically the same, independent of whether the Wagner or Grube solutions were used in determinations of D values, strengthened the authors' belief that the computed values of D (Table I) using the Wagner solution are reliable. The relative values in Eqs. 3 and 4 for the diffusion of boron in the a and ? phases, respectively, suggest that boron forms a substitutional solid solution in a iron and an interstitial solid solution in ? iron. The same tentative conclusion has been reached by McBride et al.3 on the basis of relative solubilities, atom diameter, and the size of the interstitial hole in a and ? iron. In connection with the data for test 14 listed in Table I, it is of interest to calculate the solubility of boron in a iron using the D value given by Eq. 3. As might be anticipated from the small movement of the interface in test 14, proper substitutions in Eqs. 2 and 1 give a low value, approximately 0.0004 pct B, at 850°C. Apparently at 835°C (test 13) it is possible to obtain 0.0018 pct B, and at 850°C only 0.0004 pct B into solution in the a phase before a second phase appears. These observations are consistent with the Fe-B constitution diagram proposed by McBride, Spretnak, and Speiser.3 References P. E. Busby, M. E. Warga, and C. Wells: Diffusion and Solubility of Boron in Iron and Steel. Trans. AIME (1953) 197, p. 1463; Journal of Metals (November 1953). 'W. Jost: Diffusion in Solids, Liquids, Gases. (1952) pp. 69-71. New York. Academic Press Inc. "C. C. McBride, J. W. Spretnak, and R. Speiser: A Study of the Fe-Fe2B System. Trans. ASM (1954) 46, p. 499.

Jan 1, 1955

By W. O. Philbrook, L. D. Kirkbride

IN the normal operation of the iron blast furnace, reduction of the iron oxides is accomplished almost entirely above the tuyeres.' Blast furnace slags usually contain less than 0.5 pct FeO, although higher values may occur with abnormal operation. There is reason to conjecture, however, that incompletely reduced ore may sometimes reach the hearth and enter the slag as a result of heavy slips or, perhaps, even from cores of excessively large lumps of a charge material of poor reducibility. The possibility of reoxidation of iron droplets falling in front of the tuyeres has been considered by several writers. It would be of interest, to know how rapidly iron oxides reaching the slag for any of these reasons could be reduced by reaction with coke or with the high carbon liquid iron in the hearth. In comparison with the hundreds of papers that have appeared on various aspects of the reduction of solid iron oxides by gases and in the presence of several forms of carbon, little work has been published on the reductioin of liquid oxides or slags. Dancey measured rates of reaction of the pure liquid oxides, both FeO and Fe,O,, with molten iron containing about 4.3 pct C. The oxide was dropped into the cup formed in the upper surface of the iron by rotating the crucible and melt. Under these conditions, reduction of either FeO or Fe,O., was completed in less than 10 sec. The present study was concerned with the reduction of FeO from blast furnace-type slags containing less than 5 pct FeO and melted over carbon-saturated iron in stationary graphite crucibles. The results were considerably different from those found by Dancey, as will be discussed later. Although this work is of interest in relation to hearth reactions in the blast furnace, interpretations must be made with caution because the experimental conditions do not duplicate those within a furnace and may not even lead to the same reaction mechanism. The authors were motivated in undertaking this work by an additional interest—the part played by FeO reduction in the mechanism of de-sulphurization of iron by slags under similar experimental conditions. Derge, Philbrook, and Goldman eveloped detailed experimental evidence to support a three-step mechanism for desulphurization like that originally proposed by Holbrook and Joseph' (These reactions are written in molecular form for convenience, but this is not intended to imply the existence of molecules of FeS in the bulk metal phase nor to deny the likelihood of ionic reactions in the slag.) Earlier work by Chang and Goldman" had shown that the overall reaction follows first-order kinetics with respect to sulphur and that the rate of reaction is proportional to the slag-metal interface area, which observations have been confirmed by subsequent work. Later studiese,' have established the influence of al.loying elements on the first and last steps of the reaction. This paper reports a study of step 3 alone, uncomplicated by the simultaneous process of sulphur transfer. Apparatus and Procedure The experiments were made in a conventional high frequency induction furnace powered by a 35 kva Hg spark gap converter. The graphite crucibles used for most of the runs were 14 cm (5.5 in.) deep and 4.8 cm (1.9 in.) ID with 0.75 cm (0.3 in.) wall. An insulating cover with a small opening for withdrawing samples was used to minimize heat loss and infiltration of air into the furnace. The crucible was charged with 300 g of carbon-saturated iron and either 65 or 100 g of prefused slag analyzing 38.0 pct SiO,, 15.4 pct A10 and 47.1 pct CaO. To obtain the cleanest possible interface at the start of the reaction, the metal and slag were brought to temperature together to prevent the rejection of kish graphite that would have been caused by the chilling effect of a large addition of cold slag to carbon-saturated iron. After temperature control had been established, the desired amount of iron oxide was added in the form of a prefused slag of composition 73.6 pct FeO, 7.7 pct AWX and 19.0 pct SiOl. This slag addition was observed to be molten in somewhat less than 1 min, and a very vigorous reaction proceeded for 1 to 2 min after its introduction. Zero time was taken as 2 min after the ferrous silicate slag addition. Slag samples weighing about 0.5 g each were taken periodically by a copper chill sampler." The weight of the initial slag was large relative to the weight of samples removed, so that the slag weight never varied by more than 5 pct during any run. Temperature was measured by a calibrated W/Mo thermocouple immersed in the metal, with a graphite tip cemented over the fused silica protection tube to prevent attack by slag and metal. After some difficulties with uncertain temperatures during the first two runs, the practice adopted to position the thermocouple for reproducible results was to lower the protection tube to touch the bottom of the crucible and then raise it 0.5 cm. The apparent temperature gradient between the bottom of the crucible and the top of the slag was found to be 15°C (27°F). but much of this spread was probably the result of inadequate immersion of the protection tube to off-set conduction losses along the graphite tip when the thermocouple was inserted only into the slag. The temperature of the bath was controlled within 25°C (9°F) during a run.

Jan 1, 1957

By H. J. Levinstein, H. J. Guggenheim

RbFeF3 is a transparent ferromagnet with a large faraday rotation which permits the direct observation of magnetic domain structures in bulk crystals. If the position of dislocations within the crystal were known a study of domain wall dislocation interactions would be possible. In this paper an etch pitting solution is described which gives a one-one correspondent between the etch pits and the dislocations intersecting the (100) surfaces of RbFeF3 crystals. In addition, RbFeF3 is shown to have sufficient plasticity so that known arrays of dislocaticms can be put into the crystal. It is concluded that RbFeF, is an ideal material for the investigation of domain wall dislocation interactions. THE influence of lattice defects on the motion of domain walls in ferromagnetic materials has been studied extensively both theoretically and experimentally.4 The experimental data obtained has been qualitative in nature due to the lack either of a quantitative knowledge of the magnetic domain array in the material or of the nature of the dislocation configuration in the material. At room temperature RbFeFJ has the cubic perovskite structure. It is ferromagnetic below 86°K.5,6 It is also transparent and has a large faraday rotation in the magnetic state.7 The domain structure of this material is observable in three dimensions in crystals which are millimeters in thickness.' Since RbFeF3 satisfies the requirements of having an easily visible three-dimensional magnetic domain structure, it was of interest to determine if the dislocation structure of the material could be determined and if the material was sufficiently plastic so that dislocations could be introduced into the as grown crystals. This is a report of the results of that investigation. EXPERIMENTAL PROCEDURE The crystals of RbFeFs used in this experiment were grown by a technique described elsewhere.5 In order to obtain flat strain-free surfaces, the samples were first cut to the crystal orientation desired and the surfaces were polished by employing standard metallographic techniques. The samples were then immersed in a solution of 1 to 3 g of KOH in 100 ml of water. This solution removes the damaged surface layers uniformly leaving a film on the surface of the sample. Etch pits are obtained by immersing the sample in an approximately 50-50 solution of 30 pct peroxide and concentrated acetic acid. The film formed during the KOH treatment turns deep red in color in the etching solution and flakes off the sample. The etching time required depends upon the pit size desired and

Jan 1, 1970

By W. J. Millard

IT is well known that the excellent mica from Brazil played a most vital role in World War II. Increased production from Brazil was necessary and with the assent of the Brazilian Government engineers from the United States went down to study the problem. One of the means advocated by a former Chief of Metals and Minerals Branch of the Board of Economic Warfare, Mr. Carl Schwegler, was the use of stripping machinery. On a pegmatite dike favorable for stripping, a small number of miners could produce as much mica per day as an underground mine employing many times the same number of men. TYPE OF DEPOSIT FAVORABLE The most favorable type of pegmatite for stripping is that which lies more or less parallel to the surface of the slope of a hill. Pegmatite dikes that cut directly into a hill are not suitable for stripping except where a long outcrop extends along the slope. Then just the outcrop could be stripped to some advantage. The ratio at no time should be greater than I:3; i.e., I cu. m. of pegmatite to 3 cu. m. of waste, unless the pegmatite was extremely rich throughout the dike. THE ECONOMICS OF STRIPPING When a mineral is badly needed to win a war, not too much heed can be paid to costs. The object is to produce rapidly and in quantity. Again, a deposit containing a superior grade of mica may be worked although the pegmatite is more costly to work than another deposit containing a considerably greater amount of poor-grade mica. For example: one deposit may have a little mica that will run II per cent good stain and better when trimmed and contain 2 kg. of crude mica per cubic meter of pegmatite, while another may run 0.2 per cent of good stain and better, and have a mica content of 10 kg. per cubic meter. A number of stripping projects were found in the vicinity of Raul Soares, Minas Gerais. These were sampled in the various old workings by cutting out a cubic meter of pegmatite and saving the usable mica. Because of the proximity to the surface of most stripping projects, about 34 per cent only of the mica is good for trimming. The other 66 per cent is too badly weathered to be of use. In Table I are given data collected on five properties near Raul Soares. In Table I, "value per cubic meter of pegmatite" means the value of the qualified mica obtainable. This does not include the half trimmed and splittings. By "value per cubic meter of matter" is meant the value of the qualified mica per cubic meter of material excavated; i.e. both waste and pegmatite. This is the figure that should he used to determine whether the operation will be profitable or not, as the cost of stripping is about $0.I4 per cubic meter. With new machinery not subject to breakdowns, the cost per cubic meter should be around $0.10 to $0.I5. To this should be

Jan 1, 1946

By R. C. Philp, Allan Gibb

INTRODUCTION. THE term matte is applied to smelting-products so extremely diverse in composition and physical properties that it appears impossible to devise any generic formula to represent, chemically, the manner in which the varied proportions of the almost unlimited possible constituents combine with each other. Mattes produced in copper-smelting, in distinction from those produced in smelting-operations in which the recovery of copper is secondary to that of other metals, cover a narrower range in composition. The copper-content of such mattes vary from 20 to 80 per cent., and even this range is much smaller in general practice since it is found advantageous, when possible, to produce mattes with about. 50 per cent. of copper in the first operation. Further, it is unusual that arsenic or antimony occurs in copper-ores in sufficient proportions to form arsenides or antimonides in such quantities that they will separate out from the furnace-products, as is common in lead-smelting. Generally, the mattes produced in copper-smelting are composed mainly of copper (usually greater than 35 per cent.), iron and sulphur, the remaining elements being usually in proportions sufficiently small to allow of their treatment as impurities, rather than as essential constituents of the mattes. In modern practice of smelting copper-ores in blast-furnaces the tendency is to approach pyritic smelting as nearly as pos¬sible, the furnaces being low and the air supplied being largely in excess of that required for complete combustion of the carbonaceous fuel. Hence the atmosphere of the blast-furnace thus used is usually oxidizing or Dearly neutral? and, as a consequence, the reduction of metallic iron that was a necessary evil of former practice is of unusual occurrence in operations where the main object is the recovery of copper. Hearth-accre-

Nov 1, 1905

By Henry F. Cooper, Lee Burford, John C. Thompson

In the past year or two, considerable effort has been expended to calculate the spherical wave propagation phenomena associated with explosions in a "hard rock" medium (Godfrey, 1969; McKay and Godfrey, 1969; Burford, et al, 1970). This effort was stimulated primarily by the recognition that early calculations predicted peak particle displacements which seriouly disagreed with field data. In most of the calculations mentioned above, rock was modeled as an inelastic continuum (see for example Isenberg, et al, 1970 for some recent results using "classical" elastic-plastic material property models). However, several investigators (Handin, et al, 1967; Cherry, et al, 1967) have shown that the simple classical yield surface models cannot simultaneously account for the observed brittle failures of intact materials under compression, extension and torsion. One approach to more correct modeling of dynamic rock behavior is to make the inelastic model more and more sophisticated. For ex- ample, recent experiments at the University of Utah (Swanson, 1969) have suggested possible modifications to the yield surface model that could better account for the ductile behavior of intact granite sam- ples under various states of stress. The approach followed in this paper proceeds in an entirely different direction. We want the physics which is built into our conception of rock to be as simple as possible while at the same time reproducing the most important features of rock's behavior. Therefore, we abandon the requirement that rock be treated strictly as a continuum. Instead we consider a "discontinuous" model in which one of the most significant characteristics of rock is treated..

Jan 1, 1971

By Alfred H. Bell, George V. Cohee

Illinois produced 146,788,000 bbl. of oil in 1940, or nearly 11.0 per cent of the total for the United States, and ranked fourth among the oil-producing states. Its production was only slightly less than that of Oklahoma, which produced 11.5 per cent of the national total. Illinois' production in 1940 represents an increase of 55 per cent over the previous year, when it amounted to 94,912,000 barrels. The development of the Devonian limestone in the Salem and Centralia fields is largely responsible for the increase in production during 1940 Production from the Devonian limestone in these two fields was estimated to be 36,698,000 bbl., or 25 per cent of the state's total production (Table I). The increase in production during June, when the state's daily average production attained a peak of 518,200 bbl. for the week ending June 29, was due to the Devonian production at Centralia (Fig. I). The initial production of the best Devonian wells in the Centralia field was as high as 12,000 bbl. in 24 hr. Daily average production in IIIinois for 1940 was 400,000 bbl. of oil, but actually daily production fluctuated widely during the year. At the beginning of 1940 daily production was approximately 330,000 bbl. During the first hali of the year it in-creased irregularly to the peak in June mentioned above and as the prolific Devonian producing areas were drilled up, the state's daily production declined rapidly during July and continued to decline, although more slowly, until the end of the year, when the daily production was approximately 325,000 bbl. The daily average production per well in the new fields at the end of the year was approximately 40 bbl. (Fig. I). Oil from the Devonian was also produced in the Bartelso field, Clinton County, the Sandoval field, Marion County, and the Irvington field, Washington County, bringing the estimated total production from the Devonian limestone to about 26 per cent of the state's total production, The remainder was obtained largely from the Mississippian system. About 2 per cent of the total was from Pennsylvanian and Ordovician strata. The decline in the Devonian limestone production has been so rapid that the 1941 output from this system will probably be only a small fraction of that of 1940 unless large new reserves are discovered. The "Trenton" (Ordovician) limestone has been tested in two wells in the Centralia field and both were small oil producers at a depth of about 4000 it. The "Trenton" also was found productive in the Salem field at a depth of 4500 ft. (Table 5). The initial production of the discovery well, which was completed shortly after the end of the year, was 130 bbl. on pump. Other wells drilled early in 1941 had initial productions averaging 172 barrels. The outlook for 1941 is for a continuation of drilling activity in Illinois, but at a declining rate (Fig. I, upper curve). The most active area at the end of 1940 was in the deep basin area in Wabash, Edwards, White, and Hamilton Counties.

Jan 1, 1941

By Alfred H. Bell, George V. Cohee

Illinois produced 146,788,000 bbl. of oil in 1940, or nearly 11.0 per cent of the total for the United States, and ranked fourth among the oil-producing states. Its production was only slightly less than that of Oklahoma, which produced 11.5 per cent of the national total. Illinois' production in 1940 represents an increase of 55 per cent over the previous year, when it amounted to 94,912,000 barrels. The development of the Devonian limestone in the Salem and Centralia fields is largely responsible for the increase in production during 1940 Production from the Devonian limestone in these two fields was estimated to be 36,698,000 bbl., or 25 per cent of the state's total production (Table I). The increase in production during June, when the state's daily average production attained a peak of 518,200 bbl. for the week ending June 29, was due to the Devonian production at Centralia (Fig. I). The initial production of the best Devonian wells in the Centralia field was as high as 12,000 bbl. in 24 hr. Daily average production in IIIinois for 1940 was 400,000 bbl. of oil, but actually daily production fluctuated widely during the year. At the beginning of 1940 daily production was approximately 330,000 bbl. During the first hali of the year it in-creased irregularly to the peak in June mentioned above and as the prolific Devonian producing areas were drilled up, the state's daily production declined rapidly during July and continued to decline, although more slowly, until the end of the year, when the daily production was approximately 325,000 bbl. The daily average production per well in the new fields at the end of the year was approximately 40 bbl. (Fig. I). Oil from the Devonian was also produced in the Bartelso field, Clinton County, the Sandoval field, Marion County, and the Irvington field, Washington County, bringing the estimated total production from the Devonian limestone to about 26 per cent of the state's total production, The remainder was obtained largely from the Mississippian system. About 2 per cent of the total was from Pennsylvanian and Ordovician strata. The decline in the Devonian limestone production has been so rapid that the 1941 output from this system will probably be only a small fraction of that of 1940 unless large new reserves are discovered. The "Trenton" (Ordovician) limestone has been tested in two wells in the Centralia field and both were small oil producers at a depth of about 4000 it. The "Trenton" also was found productive in the Salem field at a depth of 4500 ft. (Table 5). The initial production of the discovery well, which was completed shortly after the end of the year, was 130 bbl. on pump. Other wells drilled early in 1941 had initial productions averaging 172 barrels. The outlook for 1941 is for a continuation of drilling activity in Illinois, but at a declining rate (Fig. I, upper curve). The most active area at the end of 1940 was in the deep basin area in Wabash, Edwards, White, and Hamilton Counties.

Jan 1, 1941

By Peter Haasen

INDIUM antimonide has the zincblende structure. A possible defect that does not disturb the indium tetrahedron surrounding any antimony atom in this lattice (or vice versa) is obtained when neighboring

Jan 1, 1958

Henry M. Parks, director of the Oregon. Bureau of Mines and Geology, has supplied the following information regarding a recent discovery .of manganese ore in Jefferson County, Oregon, about seventeen miles southeast of the railroad at Eagle Point, a station on the P. & E. Railway. The occurrence is about five miles southeast of Lake Creek Post Office and near the confluence of Lost Creek with the south fork of Little Butte Creek. The manganese ore occurs as psilomelane and pyrolusite, disseminated through a flat bed of volcanic tuff breccia; at a point where the bed was penetrated by a churn drill hole, the thickness of the ore-bearing stratum was 30 ft. Development thus far has consisted of open-cuts, one of which exposes a face about 40 ft. high and 75 ft. broad. Other smaller open-cuts have followed the bed for a. distance of 400 yards. The nodules of manganese mineral vary from a maximum of 25 to 50, lb. down to the size of beans and others as small as mustard seed. These grains, when clean, average from 55 to 58 per cent. manganese. A 12-ft. groove sample in the face of the main open-cut yielded 14.86 per cent. manganese. The peculiar occurrence of the manganese nodules should present but slight difficulty in concentration. A small experimental mill was built last winter, comprising gyratory crusher, rolls, and jigs, which,

Jan 8, 1918

By Roshan B. Bhappu

This is the Centennial year of AIME and many of us reading this issue of ' will be getting ready to attend the Centennial Celebration in New York from February 26 through March 4. The officers of the Division sincerely hope that a large number of our members will attend the fine technical sessions and social functions arranged for this really big meeting. The year 1971 will be a crucial one for MBD. This SME Division is a working group organized "to furnish a medium of cooperation among those interested in the basic unit processes and unit operations of minerals beneficiation; and to promote the advancement of this branch of mineral technology through meetings for professional intercourse, and to stimulate the preparation, reading discussion and circulation of papers connected therewith." No one can deny the worthiness of these objectives or minimize the efforts that Division officers and members have made to attain them. Much has been done over the past several years to achieve a smooth-running and effective MBD organization. However, there is still room for improvement and much more needs to be done in order to provide the best possible services for the membership and the profession.

Jan 1, 1971

By C. E. Reinhard

A USEFUL accelerated weathering test should be capable of placing any series of metals quantitatively in the same order of endurance as that noted under a particular set of actual exposure conditions. The development of such a test must necessarily depend to a considerable extent upon data obtained from a wide variety of exposures. This paper offers preliminary data from exposure tests on nine metals placed in 11 locations in the Lehigh Valley, within a radius of 20 miles from Palmerton. The exposure conditions vary from a severe industrial atmosphere to a pure rural atmosphere. The data are offered as evidence of the necessity for the identification and evaluation of the variables of corrosion and as illustration of some of the variations to be considered in the development of a useful accelerated test. It is quite clear, from this evidence, that a useful accelerated test must be versatile to the extent of showing the probable variations of corrosion resulting from differences in atmosphere as well as from differences in the metals. The paper is presented solely with the object of pointing out the wide variations in relative merits of several common metals in resisting corrosion and without any thought of initiating controversy regarding the, merits of particular metals. For this reason the metals are designated only by symbols in the tables and no key is given to these symbols.

Jan 1, 1929

By Richard Franchot

From an efficiency viewpoint, the greatest loss of energy to the blast furnace is in its failure to convert more than about a third of the coke carbon from carbon monoxide to carbon dioxide. This result has usually been ascribed to a necessity of a 2:1 excess of CO in order to reduce iron. It has, however, been proved that iron is completely reduced by equal volumes of carbon monoxide and carbon dioxide. Hence there is room for the hypothesis that vaporization, as cyanid, of accumulated alkalis is a serious primary factor limiting the ratio of ore to coke. Observed cyanid vapor concentrations and those measured by the variations of the nitrogen-oxygen ratio in the hearth gases form the basis for a quantitative explanation of the furnace action. As EVERYBODY knows, the blast furnace is a gas producer. As to the reason for this, people are not so well agreed. The significance of the fact is obvious, for the extent to which the fuel leaves the furnace as combustible gas measures poor economy in iron smelting; while good efficiency in this respect means poor gas. The furnace thus works at cross purposes. The present trend of the steel industry is toward. a primary use of the blast furnace as a gas producer with pig iron as a byproduct. Needless to say, this trend is away from improvement in iron making. The production of more and better iron in a given furnace consuming a given amount of coke would seem, at least, to involve a decrease in the relative proportion of the combustible gas. The possibility at the same time, however, of making more and better gas need not necessarily be excluded. (The more the furnace acts as gas producer, the bigger is the sulfur problem.) Whatever the object, it would seem desirable to have a, clear, comprehensive, mathematically exact estimate of why and how the blast furnace functions, to the large degree that it now does, as a gas producer. The literature does not give a definite answer to the question. That for which explanation is sought is the fact that only a minor part, usually not more than a third, of the coke carbon burned is oxidized to carbon dioxide; that the development in the furnace of the fuel energy is thus limited usually to little more than 50 per cent.; that it requires about twice as much fuel coke to make a ton of iron as is indicated by the rela-

Jan 7, 1925

By H. L. Sheakley, D. J. Coolidge

This paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is cornrnonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. I). Above the sand rock an overburden of Joachim limestone appears, which thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. Properties of the St. Peter Sand From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1948

By D. J. Coolidge, H. L. Sheakley

This paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is cornrnonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. I). Above the sand rock an overburden of Joachim limestone appears, which thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. Properties of the St. Peter Sand From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1948