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By W. R. Crandall

The southern gold-fields offer some of the most complex and trying problems encountered in mining; and their successful solution often means the success or failure of the particular enterprise involved. In vein-mining, where the values are scattered over large areas, making it necessary to handle a large tonnage of very low average grade, the successful solution has been found in some instances by a combined hydraulicking and milling; water under pressure being used as the mining agent, and also for transporting the broken material to the mills, and effecting in its passage a partial concentration of the product by washing out the lighter and looser dirt of the ore-mass. The placer-deposits of the South, which were the original localities from which gold was mined, have been extensively worked, and to any one now undertaking their development offer many difficulties. The antiquity of the industry in this field, which was the cradle (in fact, literally the rocker), in which the California '49-er was born, gives assurance that all the deposits available to water and natural drainage have been more or less extensively worked already, so that, as a rule, any placer-deposits yet remaining undeveloped may be considered to offer some difficulty beyond the ability of the " old-timer " to overcome.

Jan 1, 1897

By J. H. Wilhelm, Y. Naide

Continuous thickeners can be sized from previous experience, continuous pilot-scale test results, or batch settling tests. It is relatively simple to size full-scale thickeners when previous experience or pilot-scale operating data are available. But batch testing is often the only realistic method for sizing thickeners due to time restrictions, budget limitations, and availability of sample material. Many authors have, therefore, suggested means of running batch tests and analyzing the resulting data. Fundamental thickening theory began with the work of Coe and Clevenger (1916). In order to determine the size of the thickener settling area, they proposed that a series of batch settling tests be run at various initial concentrations. The solids handling capacity at each concentration can then be determined and the lowest capacity (maximum area requirements) used to size the thickener. Kynch (1952) developed a mathematical analysis in which the relationship between solids concentration and settling rate can be obtained from a single batch settling curve. Talmage and Fitch (1955), Yoshioka

Jan 1, 1982

A mine that staggers the imagination is Chuquicamata, the granddaddy of them all. In 1968 production exceeded 300,000 tons of copper. Production began in 1915 and mining proceeded solely on oxide ores until 1953 when the first treatment of sulfides began. Today the company has mined about 1.2 billion tons of all types of material since inception. The accelerating rate of output can be gauged by the comparable 1946 figure of production-to-date which was 350 million tons. No single mine comes close to touching Chuqui for productivity at its high annual metal yield mining only 90,000 tpd of ore at the luxurious waste-to-ore ratio of 0.6 to 1. However, the complexity of the operation is enormous and the experience required to synchronize the various processes is masked by normal operations and only becomes apparent in times of emergency such as when the slide took place in the pit in February.

Jan 11, 1969

By John V. Beall

Thai means free. Historically accurate, as the country has never been subjugated by foreign occupation, the name "The Land of the Free" also seems to fit the attitude of the people. At the Bangkok airport, without so much as a kopkhun (thank you), travelers are found behind, beside and in front of ticket counters. A pretty Thai face on TV calls flights in English and Thai. Baggage disappears with alarming rapidity and your reporter and spouse despaired of ever being reunited with it. But at the entrance, all the parts came together and there was even a limousine from our hotel, The Oriental. Driving downtown English style, we noted that there were four lanes of traffic occupying the space we would allow for three lanes. Motorcycles and enclosed three-wheel motorcycle taxis were much in evidence, but the occasional water buffalo held up the slow lane. In the city, men wore European-type slacks and shirts but the women were colorful in traditional ankle-length wraparound skirts.

Jan 1, 1970

By Regis Chauvenet

I have been requested to sketch the iron resources of the State of Colorado, with reference both to existing, i.e., working mines, and to prospects more or less developed, but not contributing anything as yet to actual shipments. I should mention, though disliking apologies, that there is one region of the State which I believe to be important, and which has been assigned to me (with reference to its iron-deposits particularly) in the field-work of the present year for the School of Mines, which has not been systematically explored, and whose data are not in such shape as to enable me to give them in this paper. The region in question is Pitkin county and part of the adjoining country. Regarding the geological positions of the veins or deposits, they are sufficiently varied. In Boulder county there is a well-defined vein of titaniferous magnetite in ancient granite or gneiss, while in Park county there may be seen a deposit now under construction, as will later be described; when finished it will belong, let us say, to the post-quaternary. Between these, in Cambrian, Silurian, and Lower Carboniferous formations, are various deposits, and even the

Jan 1, 1890

By J. T. Shapland

When externally mounted sliding-gate valves are used to control the flow of metal from ladles, none of the valve components are immersed in steel. In general, the refractories used to date in sliding-gate valves have been made of a high-alumina composition. Because these refractories replace the fireclay sleeves and clay-graphite heads used to construct conventional stopper rods, they represent a major change in the use of pouring-pit refractories, Changes in the well and lining of the ladle as a result of conversion to external flow control probably will not be as severe; however, the sliding-gate valve makes it possible to preheat to a higher temperature and to decrease the turnaround time, and materials more refractory than those currently employed, such as basic brick, might be used in these areas. Another area of pouring-pit refractories that has became quite important is the tundish used with continuous casters. The use of external flow-control devices on tundishes makes it possible to use the tundish for prolonged periods of time and makes the use of better refractories necessary. In this application, high-alumina and zirconia are finding acceptance.

Jan 1, 1972

By G. S. Derrickson, R. A. Golobic

Any type of agitation within a confined vessel is primarily concerned with two parameters: a level of agitation describing the homogeneity of the constituents (whether it be suspension or mixing), and the energy efficiency with which this level of agitation is accomplished. The following is an attempt to present a solution to the problem of adequately defining and optimizing these properties. A discussion is included of the application of good design practices to the determination of a mechanically efficient shape to the blade elements of the propeller. These practices, excluding several appropriate modifications, have been known, but not well understood, in aircraft fluid mechanics for a number of years. Having optimized the direct impartation of energy to the medium being agitated, attention is turned to one of the more perplexing phenomena of multi-phase systems - definition and prediction of agitation levels. The result of recent study and testing is a method of scaling that the authors believe provides a lucid understanding of governing physical parameters within the agitator itself, allowing one to scale up and down with confidence.

Jan 1, 1985

By Joseph L. Gillson

YOUR speaker has long sought an opportunity to review the many differences between the subject matter called economic geology and the duties of a practicing economic geologist. As the subject was taught in my student days, professors teaching courses in economic geology paid little attention to what we now call industrial minerals. Certainly they were not concerned with problems involving production and marketing, but only with the origin of such mineral deposits as the Stassfurt potash deposits; with other evaporites, such as salt, gypsum, and Chilean nitrate; with the possible modes of formation of sulfur in salt domes; and the causes of asbestiform mineralization. Of course, much time and thought was given to the mineral identification and sequence of deposition of the minerals in pegmatites. The fact that such deposits actually produced commercial feldspar, mica, beryl, and lithium minerals for sale in industry was of minor importance. These observations lead us to pause to inquire, perhaps facetiously, what is and what is not to be included in the science of economic geology?

Jan 5, 1957

By R. A. Wyman

KYANITE schists in the Sudbury area have been generally described by Haw,' who has also given particuLar information on preliminary treatment of three large samples from Dryden township, Ontario.' Kyanite, garnet, biotite, quartz, and feldspar comprise the main ingredients of this ore. Kyanite is the valuable mineral. About 5½ tons of —35 +200 mesh product, made by dry rod milling, screening, and separation on the Exolon magnetic separator, were available for treatment by flotation. Magnetic separation had effectively reduced garnet and biotite so that flotation feed consisted essentially of kyanite, quartz, and feldspar, the kyanite content averaging 32 pct and representing about 86 pct of the kyanite in the original ore. Earlier work on kyanite at the Mines Branch, Ottawa, s-c employed an acid circuit, but to avoid production difficulties in the use of acids and at the same time take advantage of the fact that industrial minerals respond somewhat to soap flotation, it was decided first to investigate the higher pH levels. Exploratory tests using —65 +200 mesh feed ended with production of 96.6 pct kyanite concentrate rep-

Jan 1, 1959

By J. B. Cheatham, R. B. Paslay

Rock stresses and steady-state flow rates induced by the pressure gradient associated with the flow of formation fluid into a borehole have been analytically determined for a permeable, elastic material saturated with an incompressible fluid. In this analysis, the material properties and loading are considered to be symmetric about the axis of the borehole and independent of axial position. For Case I the material is assumed to have uniform permeability in the radial direction, whereas for Case 11 the permeability is assumed to have been reduced in a localized region adjacent to the hole by either normal well completion and production operations or deliberate plugging during air drilling. Results of a numerical example indicate that, in the absence of plugging, the rock shear strength must be approximately two-thirds the formation fluid pressure in order to prevent rock failure. The required rock strength is high for small radial zones of plugging and decreases as the region of reduced permeability becomes larger; however, a depth of plugging can be reached beyond which there is no real gain in strength, although the flow rate can be further reduced. INTRODUCTION During normal production of oil from a well, it is often desirable to increase the production rate of the formation fluid by increasing the pressure gradient through the formation adjacent to the borehole. Depending upon the magnitude of this pressure gradient and strength of the rock material, this production-rate increase can cause sloughing of the hole wall. In many cases, the production - rate increase can result in excessive sand production, increased wear of production equipment, lost production time and expensive workover jobs. In addition, the phenomenon of increased rock bit penetration rate with the use of a gaseous instead of a liquid drilling fluid has been observed in oilfield drilling operations and experimentally demonstrated by various investigators for several years. The improvement obtained by employing this technique can be quite significant and offers apromising method for reducing drilling costs. However, air drilling is currently limited to geographical locations where high-capacity water-bearing formations are not encountered. This limitation has prevented widespread adoption of air-drilling techniques, because the water influx into the borehole interferes with efficient removal of the drilling cuttings and usually results in a condition such that the bit becomes "balled-up" or stuck in the hole. In an attempt to remove the water - intrusion limitation from air drilling, various chemical and mechanical water shut-off methods have been proposed. Goodwin and Teplitzl suggested one such proposal whereby the permeability of the water-bearing rock structure was reduced in the vicinity of the borehole. Although the development of a shut-off method based upon this approach would certainly be welcomed by the oil industry, it is conceivable that, under certain conditions of the pressure gradient, strength of the rock material and depth of the modified permeability zone, a stress field can be created that will result in an unstable hole. As part of their study, an analytical solution is given for stresses in an idealized model of a hole and the surrounding rock material. The purpose of the present study is to extend the analysis of Goodwin and Teplitz to gain more insight into the details and consequences of excessive production rates and formation water shut-off. In particular, simplified models of these problems have been analytically examined, which makes possible the evaluation of the type of stress fields that can be anticipated as a result of these production and drilling practices. Both problems solved concern the determination of the steady-state volume flow rate of the formation fluid and the resulting steady-state stress and displacement distribution in a hollow, cylindrical configuration. The cylinder of Case I, corresponding to the production-rate problem, consists of a material with a constant permeability from the inside surface to the outside surface; the cylinder of Case 11, corresponding to the water shut-off problem, consists of a material with a constant permeability from the inside surface to an intermediate concentric cylindrical surface and a second constant permeability from the intermediate surface to the outside surface-

By Y. Kondo, S. Yamazaki, Z. Asaki

Thermal deco7nposition of Pyrite particles in a fluidized bed with inert gas stream was studied. Assuming that heat transfer from the surroundings to the fluidized particles controls the overall decomposition rate, rate equations for the batch process and for the continuous process were derived. In the batch experiment, a linear rate equation satisfies the experimental results and the overall heat transfer coefficient calculated from the rate constant agrees fairly well with that obtained by Leva.l1 For the continuous process, two rate equations were derived, one on the assumption of complete mixing of particles and another on the upward piston flow of particles in a fluidized bed. The former holds for a bed containing a higher fraction of decomposed pyrite realized at lower feeding rates. The latter can be applied for a bed at higher feeding rates. Thus, segregation of particles in the fluidized bed was indicated at higher feeding rates. Bed temperatures also correspond to these conditions. ThERMAL decomposition of pyrite may be represented by Eq. [I]. The pressure of diatomic sulfur gas reaches 1 atm at about 690°C. The thermodynamics,' kinetics,2'3 composition, and properties3-5 of decomposed products of such a reaction have been studied. Pyrite is a very common sul-fide mineral and is often accompanied with other sul-fides. It is of basic interest in nonferrous metallurgy to clarify the behavior of pyrite in the pyrometallur-gical processes of sulfide minerals of metals such as copper, lead, zinc, nickel, and so forth. Interest in this reaction increased recently because of possible elimination of arsenic from pyrite in processing highly purified iron oxide pellets. Producing elemental sulfur from pyrite, instead of sulfuric acid, also aroused interest in this reaction. It is indicated that the thermal decomposition of solid particles, such as calcium carbonate, proceeds through three major sequential steps: heat transfer, interfacial chemical reaction, and mass transfer.637 It is known that the decomposed product of pyrite is very porous2, 3 and the diatomic sulfur gas evolved can easily escape through this layer of decomposed product. It depends upon the circumstances, therefore, whether the heat transfer to the interface within particles or the chemical reaction at the interface determines the overall decomposition rate. The enthalpy change in the decomposition of pyrite is about 33 kcal per mole FeS2 which is comparable to that of calcium carbonate. The decomposition of calcium car- bonate becomes more and more dependent on the rate of transport of heat when reaction temperature increases, such as occurs in a fluidized bed.6'7 It is reasonable to presume, therefore, that the thermal decomposition of pyrite, an endothermic process, carried out in a fluidized bed may be analyzed according to the heat transfer controlling model. This work intends, first, to propose a mathematical model that determines the overall rate in a fluidized bed for the decomposition process and, second, to investigate a few characteristics of the fluidized bed based upon the experimental results obtained. KINETICS OF THERMAL DECOMPOSITION IN A FLUIDIZED BED It is intended in this section to obtain rate equations for thermal decomposition of pyrite in a fluidized bed by assuming that the overall rate is determined by heat transfer from the surroundings to the particles. Both batch and continuous processes are considered. 1) Batch Process. To obtain the rate equation in the batch process, the following two additional assumptions are made. First, the temperature of preheated inert gas, tg, blown into the fluidized bed is assumed to be the same as the temperature of the fluidized bed, tf. Thus, no heat exchange occurs between the gas and particles in the bed and only the heat transfer from the reactor wall kept at tw to the particles is to be considered. Second, the decomposition is assumed to start at the outer surface of the particles and to proceed toward the center. At any given time during decomposition, undecomposed pyrite remains in the tori at a temperature: td. The decomposed shell is composed of FeS1+x whose outer surface is at tp Diatomic sulfur gas evolving at the interface is heated to tf during its escape through the decomposed shell. This is illustrated in Fig. 1. With the above-mentioned assumptions of heat transfer, we have:

Jan 1, 1969

By C. F. Quest, T. S. Washburn

The steel industry has a definite need in its tonnage mills for a formula relating expected tensile strength to the analysis of the steel. The McWilliam-Barnes1 and other less comprehensive formulas are used for this purpose, but these formulas were designed for an analysis range that does not include the medium manganese and silicon-bearing steels. This type of steel is being produced to meet the demand for tensile strength slightly higher than that of ordinary structural steel but not high enough to justify expensive alloy steels. The purpose of this paper is to present a somewhat more comprehensive formula based on data accumulated over a number of years by the Inland Steel Co., and to discuss the method followed in obtaining a formula to fit the data. The resultant formula admittedly is still weak in some respects, but for the expanded analysis range appears to be an improvement over the other formulas. It is hoped that with the collection of more data and possible collaboration with other mills studying this problem it will be possible to work out a more nearly perfect formula. Several publications have been issued on this subject. In some, the equation type of relation was evolved while others made a combination of tables and an equation. The latter include work by Campbel12,3 and Webster.4,5 Campbell classified the steels as acid and basic and applied a different formula to each. For basic steels, he used the equation: Teosile etrength = 41500 + 770C + 1000P + yMn [1 y was a variable depending on the carbon and manganese content of the steel and was listed in tables. Webster investigated acid Bessemer steel and developed the equation: Tensile strength = 38000 + 800C + xTP+ yMn [2]

Jan 1, 1940

By C. K. Leith

THE questions as to what grades of ore it pays to conserve for the future, and the valuation of low-grade reserves, are becoming immediate and definite as applied to individual ore deposits, and seem to call for some sort of quantitative answer. Both opinion and practice involving these questions differ widely. The number of variables in this problem is so large that final solution will perhaps never be agreed upon, yet there seem to me to be certain controlling factors which can be placed in quantitative relation and serve to reduce the number of variables which it is necessary to consider in a given instance. I assume that it will not pay either for the individual or for the State to conserve any ore when the present cost of conservation (by stock piling or otherwise), when compounded at 6 per cent. interest for the number of years which would elapse before this ore is used, will exceed the profit which the ore will yield when it is used. It may be urged that any loss to the individual may be made up in gain to the State. This might be true if there was any definite limit to the amount of iron ore, but when we remember that iron makes up .4 per cent. of all the rocks of the earth and the amount of rock carrying iron in excess of 20 per cent. is for practical purposes, unlimited, it is apparent that posterity is assured of its iron ore. The changes will be mainly in methods and cost of extracting the ore. Therefore, any expenditure of money or effort now, which when compounded will exceed the worth of the effort or money needed in the future to utilize the iron, is a net loss both to the individual and to the community.

Jan 2, 1914

By M. E. Volin, D. W. Fuerstenau, A. L. Mular

This paper presents the results of an investigation of the effect of feed size on the integral rate at which feed material is dry ground in a laboratory rod mill. The data are interpreted in terms of the Gaudin-Meloy distribution equation. The equation, Mo — Mt/t = Aoxo r-1, is found to hold for feed sizes smaller than some critical size or for grinding times larger than some critical time. It is shown that a feed grindability is related to this critical size, which appears to be the transition between predominately impact and predominately attrition grinding. Detailed research on feed size effects in comminution has been rather limited. Gaudin1 ground single-sieve fractions of quartz for extended time periods (four hours) in a laboratory ball mill. His work, which was designed to study the nature of size distributions, showed that there is a critical feed size above which comminution occurs primarily by attrition. For his system, the critical size was about 2-mm when using 22-mm balls. In a more recent investigation2 single-sieve fractions of quartz were ground in a laboratory rod mill for constant time periods (15 min) to determine how feed size affects the grindability of the material. This work showed that grindability is essentially independent of feed size in the rod mill after this moderately long grinding period. To further clarify this observation, a study in which feed size and grinding times are varied over a fairly wide range, and particularly, a study of the dependence of the integral rate of grinding on feed size during the initial stages of rod milling is necessary. For an analysis of such data, it is desirable to use a parameter which is very sensitive to change during the initial grinding period when reduction ratios are

Jan 1, 1964

By C. F. Quest, T. S. Washburn

The steel industry has a definite need in its tonnage mills for a formula relating expected tensile strength to the analysis of the steel. The McWilliam-Barnes1 and other less comprehensive formulas are used for this purpose, but these formulas were designed for an analysis range that does not include the medium manganese and silicon-bearing steels. This type of steel is being produced to meet the demand for tensile strength slightly higher than that of ordinary structural steel but not high enough to justify expensive alloy steels. The purpose of this paper is to present a somewhat more comprehensive formula based on data accumulated over a number of years by the Inland Steel Co., and to discuss the method followed in obtaining a formula to fit the data. The resultant formula admittedly is still weak in some respects, but for the expanded analysis range appears to be an improvement over the other formulas. It is hoped that with the collection of more data and possible collaboration with other mills studying this problem it will be possible to work out a more nearly perfect formula. Several publications have been issued on this subject. In some, the equation type of relation was evolved while others made a combination of tables and an equation. The latter include work by Campbel12,3 and Webster.4,5 Campbell classified the steels as acid and basic and applied a different formula to each. For basic steels, he used the equation: Teosile etrength = 41500 + 770C + 1000P + yMn [1 y was a variable depending on the carbon and manganese content of the steel and was listed in tables. Webster investigated acid Bessemer steel and developed the equation: Tensile strength = 38000 + 800C + xTP+ yMn [2]

Jan 1, 1940

By Colin Rae

THE absence of paraffin and other oil hydrocarbons in the soil, although they are concentrated in extensive deposits in some localities, the common distribution of plant remains through many formations that .are not productive for oil, and many other factors, seem to indicate the existence of an intermediate organic compound between the complex plant compounds and the petroleum hydrocarbons; and much evidence points to the humus acids or associated organic compounds, which are probably collected by surface waters and concentrated in certain areas by means of precipitation by electrolytes, which would be contained in sea water or possibly in various inland seas or lakes. PRESENT-DAY EVIDENCE There are many present-day evidences of the association of petroleum with humus acids. Binney, in 1912, made observations without explanations on the peat mosses of Down Holland, England, where he found petroleum being formed by decomposition, in the presence of an infiltration of sea water. The analysis of a typical peat will show its relationship to the humus acids under consideration. SAMPLE 'No. 1, SAMPLE NO. 2, PER CENT. PER CENT. Water : 20.0 29.5 Ash 3.0 3.05 Fiber 47.0 54.95 Humus acids 30:0 12.50 J. D. Haseman and others have noted the association of asphalt and hydrocarbons with the swampy, boggy areas, particularly adjacent to the sea.

Jan 2, 1922

By U. Oko

The cause and the effect of disposing of tailings water from sulfide ore milling operation were examined. Dissolved metallic ions as well as dissolved sulfur-oxygen compounds (polythionates) can prove injurious to life in water streams. Polythionates originate in alkaline flotation circuits and may cause a severe drop in the pH of stream waters. It is proposed that a suitable "aging" period be allotted to tailings water to ensure complete conversion of polythionates to sulfate prior to neutralization and clarification treatment. Discharging alkaline solid-free tailings water without aging will cause downstream acidification. Artificial oxidation of tailings water can be economical only if the concentration of thiosulfate in solution is low. When the concentration is high, it is possible to reduce the concentration greatly by first acidifying the solution, because at a pH below 4 thiosulfate in water reacts to produce a precipitate of elemental sulfur and higher order polythionates. The residual polythionates can then be oxidized at great savings by natural aging or by chemicals such as ozone, chlorine, or peroxide. Chlorine may be an economical reagent for converting polythionates to sulfuric acid but the residual organo-chlorinated compounds can prove to be toxic to aquatic life. Ozone and hydrogen peroxide which do not leave a residue are preferred oxidizers.

Jan 1, 1976

By O. Chanute

In discussion of Mr. Macdonald's paper, I can say little more thau to add t~ the general acknowledgments of iguorae, and like several of the gentlemen who have preceded me, make one of those confessions which are thought to be good for the soul. Having had some experience in the erection of bridges during past years, I am aware that We yet need much information in order to proportion them to the best advantage. I would more especially like to emphasize three of the points mentioned by Mr. Macdonald, as among those upon which we lack knowledge; these are: first, the behavior of steel; second, the proportions of compression members; and, third, the influence of the size of a bar upon its strength per square inch. First, as to steel. While we all acknowledge this as the material of the future, our position map be said to be still one of expectaucy. Feu? engineers are bold enough to employ it largely in bridges, and those who do, find such serious difficulties in obtaining uniform grades of it, are so puzzled by apparent anomalies and unexpected phenomena, that it requires considerable faith and courage to apply it in large structural masses. A series of systematic experiments,

Jan 1, 1882

By T. F. Witherbee

That the single charging-bell, properly proportioned, is a good all-around device for distributing material in a blast-furnace can scarcely be questioned; yet it is equally true that, in some cases, it has not given perfect satisfaction; as has been demonstrated by the substitution of double bells, at furnaces under the beat management—generally in cases where anthracite, either alone, or with a portion of coke, was used as fuel. The defect of the single bell seems to be that it does not permit, beyond very narrow limits, such changes in charging as may be required by the temporary conditioil of the furnace. Modern furnaces using Connellsville or other good coke and Lake Superior ores seem to be well served with a single bell. At least, up to a certain size, somewhere about 18 by 85 ft. to 19 by 90 feet, these furnaces make low-silicon pig-iron with about 1,800 lb. of fuel, or in some cases very much less. The following instances occur to me, in which other forms of charging-apparatus have been employed with advantage: 1. A charcoal-furnace, 61 ft. high, 11 ft. in diameter at bosh, and 8 ft. 2 in. at stock-line, with a rectangular crucible, 42 by

Jan 1, 1905

By F. R. Hensel

The present study was made to determine the laws governing the formation of the primary? crystal structure during solidification. Most of the experiments were carried out on chill castings, but from the resiilts it will be possible to draw certain conclusions as far as sand castings are concerned. It is necessary to discuss first a number of theories, which are generally adopted for explaining the structure of an ingot. Usually, the structure of an ingot consists of the following three zones (Fig. 1): (1) a chill layer of small at-random oriented crystals; (2) a layer of columnar crystals; (3) a zone of equiaxed crystals. The tensile properties of the chill layer and the equiaxed range are usually much better than in the columnar range, particularly the planes that are formed by the columnar crystals growing from two sides at right angles have low tensile properties. This is one of the reasons why columnar crystals in ingot structures are undesirable.

Jan 1, 1937