Search Documents

By Walter R. Hibbard, Cyril Stanley Smith

IN 1929 one of the authors1 determined the constitution of copper-silicon-manganese alloys contailling over go per cent copper. Through a combination of circumstances the presence of the copper-silicon kappa phase was overlooked in both binary and ternary systems. In the binary system the omission has already been rectified.2,3 To establish the limits of this phase in the ternary system, the samples that had been heat-treated at the time of the original research have now been re-examined, using more careful technique. Full details of the compositions used and the temperatures and times of heat-treatment are to be found in the earlier paper.2 The etching reagent now used to distinguish the kappa phase had the following composition: hydrogen peroxide (30 vol.), 2o c.c.; water, 25 c.c.; 20 per cent potassium hydroxide solution, 5 c.c.; ammonium hydroxide (0.90 sp. gr.), 50 c.c. 'I'able I lists the newly observed structures. In virtually every case the constituents are the same as those previously recorded, except where kappa is now shown to be present as a result of the improved etching technique. X few other changes will be noted (No. 138 at 450°C., No. 147 at 550°C., Nos. 153 and 149 at 75o°C.). The change from liquid to beta in equilibrium with kappa in No. 137 at 800°C. is based upon newly heat-treated samples. The alloy is very near the solidus at 800°C. and probably there was a slight error in the old heat-treatment temperature. The isothermal phase diagrams shown in Figs. I to 6 were reconstructed on the basis of the new studies. The presence of manganese does not greatly change the composition limits of the kappa phase or cause the K-a + Y change to occur at a markedly different temperature. There is some uncertainty regarding the range of existence of beta, for alloys were not spaced very closely in composition. The proposed diagrams, however, are in accordance with the available experimental data and with the dictates of the phase rule. Theoretically necessary fields with no experimental points are delineated by dotted lines. The alpha boundaries at all temperatures are shown together in Fig. 7. This includes also some additional points on the alpha boundary at 300' and 350°C., which were obtained as a result of electrical-conductivity measurements. Two series of seven alloys with increasing manganese content but with silicon constant at 1.90 + 0.03 per cent or 2.42 ±. 0.05 per cent were cast in ingots of 3-in: diameter. These were hot-rolled, homogenized and drawn to wire, finished at 0.08-in. diameter with a 61 per cent reduction of area following annealing at 700°C. Conductivity determinations were made before and after annealing for 30 days at 300°C. or 21 days at 350°C. Figs. 8 and 9 show the change of conductivity produced by this annealing, plotted against manganese

Jan 1, 1942

By Curtis Wilson

FROM the results of his investigation of the hardenable copper-nickel-silicon and copper-cobalt-silicon alloys, M. G. Corson1 explained the dispersion-hardening effect by assuming the precipitation of the inter-metallic compounds nickel silicide and cobalt silicide, and on this basis he constructed diagrams for the pseudobinary systems copper-nickel silicide and copper-cobalt silicide. A consideration of these diagrams and of the factors that exert such an important influence upon the rate of precipitation, such as degree of supersaturation, nucleus number and rate of diffusion, leads to the expectation that the rate of precipitation of the silicides on reheating the quenched solid solutions at temperatures below the alpha-phase boundary should increase continuously as the reheating temperature is raised. The present investigation shows that while this rate does increase with the reheating temperature in a general way, it does not do so continuously. Supplements to Corson's diagrams are offered, showing the discontinuities, and slight modifications in the solubility curves are suggested.

Jan 1, 1933

By Thos Stroup

RECENT contributions to the literature relating to the problems of coal mine management have discussed the pros, and cons of unionism among the miners as bearing upon the immediate problems of the industry, but have devoted singularly little thought to the underlying causes, and the fundamental reasons. for the remarkable growth of union sentiment among the miners, a growth paralleled only in the case of the railroad workers. It is all very well to revile their organization, its obvious stupidity and stubbornness, its multitude of economic and social crimes, but it is also well to realize that there have been deep-seated causes for all these things, causes that, while operating in all industries and amongst all workers, have in none of them found the optimum conditions for development such as exist in the coal mining industry. The rise of the United Mine Workers of America to a position of importance in the industry synchronizes roughly with the introduction of short-time operation; of course seasonal shutdowns and slow-time working have always been evident in our bituminous fields, but these evils have grown steadily worse since 1895 and the U. M. W. of A. has grown steadily stronger; yet short-time operation alone cannot account for this tremendous growth for, witness the signal failures that have always attended the attempts to organize the harvest workers, the fruit packers and other highly seasonal workers.

Jan 9, 1923

By Jay Carpenter

THIS paper deals with only one step in the treatment of ore at the West End mill; not because the other steps are repetitions of practice in other mills, but because in this particular step there is in use the Trent agitator. This device, although it has apparently failed in many mills, is here giving excellent service and has proved to be well adapted for making a thorough replacement of pregnant solution with a minimum amount of barren solution. The strong and weak points of this agitator, its present simple construction, and its use as a thickener for agitator or battery pulp are features of interest; but perhaps the point of greatest interest to the metallurgist in this day of continuous decantation is its use in a series of tanks for slime treatment by the replacement method. The agitating department of the West End mill consists of six redwood tanks, 24 ft. in diameter, 18 ft. high, each equipped with aTrent agitator, a centrifugal pump, and a motor. The pulp is transferred by a pump from the top of a flat-bottomed tank to a set of arms and nozzles in the bottom of the tank, at just sufficient pressure to cause the arms to revolve. The streams from the many nozzles keep the bottom of the tank clean, and these streams, coupled with the effect of the revolving mechanism and the ascending current, keep the pulp in constant motion and of constant gravity. .These agitating tanks hold 90 tons of dry slime and 202 tons of solution with a 1.24 pulp, our ore having a specific gravity of 2.7. This capacity is about 10 per cent. in excess of the standard 15 by 45 ft. Pachuca tank. The tanks are connected in one series for continuous agitation, the pulp for each agitator being drawn by its pump through a branch suction from near the top of the preceding tank and. delivered to the bottom of the tank by the agitator arms along with the regular pulp of that agitator. This method works automatically, since the flow through the branch suction varies directly with the difference in head of the two tanks. The chance for new pulp to pass out quickly is, therefore, much less than in many other systems of continuous agitation, since the new

Jan 8, 1915

JAMES DOUGLAS Dr. James Douglas, twice President of the American Institute of Mining Engineers, and one of its principal benefactors, died in New York on June 25, 1918, at the age of 81 years. After a life of extraordinary activity, failure of his health compelled him to retire about 2 or 3 years ago, and in view of his advanced years his death was not unexpected. His funeral was held at the Church of the Mediator, on June 26, and was attended by representatives of the American Institute of Mining Engineers and of the Canadian Mining Institute. His body was then taken to Quebec for burial in the family plot. An extended notice of Dr. Douglas, prepared by Dr. R. W. Raymond, will be presented in the September issue of the Bulletin. LEWIS NEWTON BAILEY Lewis Newton Bailey died of pneumonia at Camp Merritt, N. J., April 30, 1918, at. the age of 34 years. He was Master Engineer, .Senior Grade, in the Fourth Regiment, U. S. Engineers; and although he was offered a commission as First Lieutenant shortly after enlisting, he preferred not to accept it until he had reached France. By those who knew him well, this lack of eagerness for promotion will be recognized as consistent with his whole character.

Jan 8, 1918

By Henry Schwellenbach

LABOR shortages, rising wages, and changes in moisture and fines content of the ore necessitated a review of the flowsheet at Warren Foundry & Pipe Co's. Mt. Hope, N. J. Mines Div. This plant had been designed prior to World War II, and started operations in January 1945. When this operation was designed there was an oversupply of labor in the area, wages were at a reasonable level, the run-of-mine ore was low in moisture, and there was a limited amount of fines. These factors all favored use of hand picking for cleaning rougher lump concentrate. Since that time, many changes have occurred. The proximity of defense industries and large military installations, has created one of the most acute labor shortages in the country. This labor shortage together with present wage levels, and the increase in moisture and fines in the ore created several problems. The increase in moisture and fines may be attributed to changed mining methods, the extensive use of sprays, and the opening of new mining areas bringing an increase in ground water. [ ] Two problems were presented by the increase in moisture and fines. The first was that lump ore arrived at the open hearth in an unacceptable condition, due to the segregation enroute of the large amount of fines that had adhered to the lumps. The second problem was that high magnetite content fines coated the large lumps, making it difficult for pickers to distinguish middling by other than the relative weight. [ ]

Jan 1, 1952

By E. J. Ripling

TUBES may be produced by a large number of forming processes, the most common of which will be discussed analytically in this paper. In no case will the stress analysis for any given tube producing process be derived formally for where such analyses are available, they may be referred to readily. Rather, emphasis will be placed on the interpretation of the theory of the different processes, few of which are developed to a state that will allow rigorous mathematical analyses, in an attempt to give a rational description of the effects of the different variables involved in each method. Tube producing methods can be divided into two groups: Those used to form shells, and those used to further work these shells into a shape more suitable for their final use. Among the first group are included roll piercing, extrusion and cupping for seamless shells, and bending with welding for welded tubes. The re-forming processes include sinking, drawing with a plug, and drawing with a rod. Only the plastic forming operations will be discussed here; other forming processes such as casting shells will not be considered. PRODUCTION OF SHELLS Shells for Seamless Tubing Piercing: The extremely important process of forming an axial hole in a billet by oblique rolling never has been analyzed satisfactorily, although a certain amount of experimental work relating to this process has been conducted. There are a number of factors that make piercing difficult to analyze; one of these is the fact that piercing is not a problem in plasticity, but one in fracturing, and the laws of fracturing are even less well understood than those of plasticity. If, however, it is assumed that fracturing occurs on a surface as a result of tensile stresses acting normal to this surface, piercing can be analyzed qualitatively by examining the stresses established in the oblique rolling process. To determine the origin of the tensile stresses that are thought to effect piercing, it will be necessary to know the angular relationships between the maximum stresses that are established in piercing. These angles quite frequently can be determined in a plastic deformation process by an examination of the deformed product. For example, consider the stresses established when a tensile test is conducted on a rectangular cross-sectional specimen of pearlitic steel. When stretched, this material first flows plastically, exhibiting the well-known yield jog on a stress-strain curve. The formation of the slip areas that give rise to the yield jog can be detected during the straining, since these flowed areas cause depressions on the specimen surfaces which can be seen if the surfaces are polished highly. The plastically strained areas also can be found after the specimen has been stretched to a strain not exceeding the yield jog, by sectioning the test piece and. etching these sections with Fry's etch. With this etchant, it is possible to dis-

Jan 1, 1951

The mining fraternity of North America was grieved and shocked to learn of the death of Dr. Willet G. Miller on Feb. 10, 1925. Doctor Miller was for many years the Provincial Geologist of Ontario and the one who more than any other had contributed by his personal work and the reports of his subordinates to the recent extraordinary mineral development of the Province. Doctor Miller was fifty-eight at the time of his decease. A man of unusually stalwart physique, he seemed destined to many years of useful service. His friends in both the American and Canadian Mining Institutes can with difficulty reconcile themselves to his loss. Doctor Miller was born in 1867 in Port Rowan, Ont., on the shores of Lake Erie. After preparation in the high school of his native town, he entered the University of Toronto and took his bachelor's degree in 1890. He pursued graduate studies in geology at Chicago, Harvard, and Heidelberg Universities. In 1893, he was first appointed lecturer and soon thereafter Professor of Geology in Queens University, Kingston, Ont., a chair which he held until 1902. He was then appointed Provincial Geologist of Ontario and was placed at the head of the Survey which was attached to the Department of Mines. Within the next year, 1903, he performed the service that made him famous. In the summer of 1903, in connection with the building of the Ontario Government Railway toward an objective on James Bay, veins had been noticed by construction parties just north of what is Cobalt Lake today, and in the rocky pass that is now traversed by the main line of the Canadian National Railway en route to Vancouver. The pink stain of cobalt bloom on the vein, known later as La Rose, caught the eye of a workman; in November, Doctor Miller recognized the silver in it, and brought the possibilities of the district to general attention. In December, he published an article in the Engineering and Mining Journal, stating that the veins could be worked at a handsome profit. During the winter and spring, the mining interest awoke, which resulted in the astonishingly productive silver district of Cobalt; but in which, Doctor Miller, because a government official, scrupulously refrained from having any financial interest whatever. Seldom has so high a sense of honor been manifested; and as the result, Doctor Miller commanded confidence and respect to an extraordinary degree. Hard on the discoveries at Cobalt came, in the next few years, those at the other famous camps in Northern Ontario; and step by step with them, reports issued from

Jan 1, 1925

By A. R. Denison

The area discussed in this report comprises a group of 38 counties lying in the northeast corner of Texas. It covers all, and extends beyond, the borders of what is commonly described as the East Texas Basin. It includes two major oil fields, Van and East Texas; two major gas fields, Bethany and Waskom; and a number of fields, both oil and gas, of lesser importance. All commercial oil production comes from beds of Upper Cretaceous age and almost exclusively from the basal member, the Woodbine sand. Gas is produced from both Upper and Lower Cretaceous beds with the newer production from the older beds. East Texas Field This field continued as in 1932 and 1933 to dominate the drilling and production situation throughout the oil business. A total of 3681 producing wells was completed in this field during 1934. This is an increase of 1215 over the 2466 producers completed during 1933. Total wells

Jan 1, 1935

By M. Shelef, A. W. Fletcher

The effect of alkali sulfates in promoting the sul-fation of nickel and copper in a bulk sulfide flota -tion concentrate by fluidized bed roasting has been studied in the laboratory, and it was shown that the various alkali sulfates promote sulfation to approximately the same extent. The sulfation of a mixture of synthetically prepared iron and nickel oxide and of nickel ferrite has also been studied. Nickel sulfation was promoted by high ratios of Fe:Ni and by the presence of sodium sulfate. THE work described in this paper was a continuation of earlier studies into the role of alkali sulfates in promoting the sulfation roasting of nickel sulfides1,2 in an endeavor to determine how the system was affected by the presence of compounds of iron and copper. The earlier work1 showed that, in the sulfation of NiO at 680°C, the reaction was limited by the formation of an impermeable film of nickel sulfate on the oxide surface. The relative effect of the various alkali sulfates in promoting nickel sulfation varied in the order: Li > Na >Cs > Rb > K A study of alkali sulfate/ nickel sulfate interactions at high temperatures showed that the promoting action was due to the fact that the nickel sulfate product layer sintered and agglomerated only when the more active additives were present. This resulted in the formation of discontinuities in the nickel sulfate layer so that diffusion of the sulfating gases to the NiO surface was no longer impeded and the reaction could proceed to completion. A similar explanation was used for the observation that sodium and lithium sulfates promote the oxidation of NiS to NiO at temperatures below 750°C since small amounts of nickel sulfate were formed during oxidation.2 It was of interest to study the effect of alkali sulfates on the sulfate roasting of a sulfide flotation concentrate which is typical of material treated commercially. In order to control temperature it is essential to roast sulfides in a fluidized bed and this technique was therefore used, although the batchwise operation of a small-scale laboratory reactor does not reproduce all conditions which prevail in full-scale continuous plant. The results obtained are therefore only comparative, and cannot be used for predicting the optimum conditions for metal extraction. The sulfation of synthetically prepared mixed oxides of nickel + copper and nickel + iron and of nickel ferrite was also studied to evaluate the relative effects of alkali sulfates with more complex systems. SULFATION ROASTING OF A SULFIDE FLOTATION CONCENTRATE The bulk sulfide flotation concentrate used in this work contained 7.92 pct Ni, 1.74 pct Cu, 35.66 pct Fe, and 31.28 pct S. The sulfide minerals present in order of abundance were pyrrhotite FeS, pyrite FeS2, pentlandite (FeNi)S, and chalcopyrite CuFeS2. Two samples described as coarse and fine were used. The coarse sample, which was a flotation concentrate (58 pct plus 300 mesh), was ground to 100 pct minus 350 mesh to produce the fine sample. Before roasting, the sample of sulfide concentrate was agglomerated by wetting witli a solution of the alkali sulfate (or water), thoroughly mixing, and drying at 110°C. This gave a cake which was gently crushed and screened, the -18 +100 mesh fraction being used for fluidized bed roasting. A similar-size fraction had been used by the authors in pilot plant work with a 4-in.-diam fluidized bed reactor.' In this work it was found that the molar ratio of additive to the total iron + nickel + copper content of the sulfide sample should be adjusted to a value of approximately 0.06, as this was the optimum amount necessary for nickel sulfation. Experimental. The fluidized bed reactor consisted of a quartz tube approximately 60 cm long and 30 mm in diameter resting in a vertical tube furnace. The sulfide bed (30 g) was supported on a bed of -4 +12 mesh quartz particles 3 cm high, which rested on a sintered quartz disc welded to the tube. The temperature of the furnace was controlled with a variable transformer to give a final bed temperature of 680°C. The bed was fluidized with air or mixtures of air + 10 pct v/v SO2, at a total apparent gas velocity of 60 to 65 cm per sec at 680°C. The SO2 was introduced into the fluidizing air stream only when the oxidation of the sulfides was completed. At the end of the roasting period the calcine was leached with boiling water and the

Jan 1, 1964

By J. Volney Lewis

The following paper is based chiefly on work done for the North Carolina Geological Survey, and is presented here by permission of Professor J. A. Holmes, State Geologist. It represents, in a very general way, the field-results obtained during the summer months of 1893, and 1894, and part of 1895; and the portions pertaining to North Carolina are, to a certain extent, abstracts of a report shortly to be published as Bulletin No. 11 of the State Survey. Less emphasis, however, is here laid on the petrographic descriptions of the peridotites, and more detailed treatment is given to subjects pertaining to methods of mining, cleaning, and utilization of the commercial product, corundum. Some of the most extensive fields for investigation which this subject presents have been scarcely more than suggested.

Jan 1, 1896

By D. E. Hyatt

Many flotation plants practicing pyrite depression, mills leaching gold and silver ores, blast furnace facilities, and many metal plating shops share at least one common waste-water constituent of particular environmental concern-cyanide. In free or complexed form, cyanide ion is an emotionally and technically problematical reagent whose removal from water deserves attention. The initial consideration of the fundamental nature of soluble cyanides is followed by a discussion of decomposition or removal options for simple cyanide species. Complexed cyanide reactivity is discussed as it relates to ongoing or proposed methods for the decomposition or removal of soluble cyanides. New approaches to cyanide removal are discussed.

Jan 1, 1977

By Guillermo Zuloaga

The iron deposits of the Imataca Range of Venezuela, which occur along the Orinoco River, in the northern border of the Guayana Highlands, have lately attracted attention on account of their economic possibilities. Many deposits occur in this area; some of slight economic importance and others that may rank with the largest masses of high-grade iron ore of the world. The geology and the character of the ores seem to be remarkably similar to those of the large iron deposits of Brazil. In the investigation of the Venezuelan deposits a definite relationship has been found between the mineralization of the large orebodies and igneous intrusions, especially norites and granites. The following paper is the result of a field and laboratory investigation of the ore deposits. The field work was done during the months of February and March of the year 1929, partly in the company of Prof. W. H. Newhouse. The laboratory studies have been made in the Massachusetts Institute of Technology, under the supervision of Professor Lindgren and Professor Newhouse. GENERAL GEOLOGY OF GUAYANA HIGHLANDS General Geography and Physiography The Sierra de Imataca proper occupies a narrow belt along the south bank of the Orinoco River, in the northeastern part of the State of Bolivar and in the western part of the Delta Amacuro Territory of Venezuela. The State of Bolivar is generally known as the Venezuelan Guayana, as it forms part of the same physiographic province of the Guianas and northeast Brazil. In general the Venezuelan Guayana is an extensive plateau, sloping gently towards the Orinoco River to the north and towards the Atlantic Ocean to the east. In the northern part mountains are rare, and consist mainly of elongated low hills. Towards the British Guiana-Brazil boundary, table mountains with vertical cliffs are found forming the ranges of Parima, Roraima and Pacaraima. General Geology The Guayana Highlands are the northern extension of the Brazilian Archean shield. Only a few scattered masses of sediments remain on its

Jan 1, 1935

By Guillermo Zuloaga

The iron deposits of the Imataca Range of Venezuela, which occur along the Orinoco River, in the northern border of the Guayana Highlands, have lately attracted attention on account of their economic possibilities. Many deposits occur in this area; some of slight economic importance and others that may rank with the largest masses of high-grade iron ore of the world. The geology and the character of the ores seem to be remarkably similar to those of the large iron deposits of Brazil. In the investigation of the Venezuelan deposits a definite relationship has been found between the mineralization of the large orebodies and igneous intrusions, especially norites and granites. The following paper is the result of a field and laboratory investigation of the ore deposits. The field work was done during the months of February and March of the year 1929, partly in the company of Prof. W. H. Newhouse. The laboratory studies have been made in the Massachusetts Institute of Technology, under the supervision of Professor Lindgren and Professor Newhouse. GENERAL GEOLOGY OF GUAYANA HIGHLANDS General Geography and Physiography The Sierra de Imataca proper occupies a narrow belt along the south bank of the Orinoco River, in the northeastern part of the State of Bolivar and in the western part of the Delta Amacuro Territory of Venezuela. The State of Bolivar is generally known as the Venezuelan Guayana, as it forms part of the same physiographic province of the Guianas and northeast Brazil. In general the Venezuelan Guayana is an extensive plateau, sloping gently towards the Orinoco River to the north and towards the Atlantic Ocean to the east. In the northern part mountains are rare, and consist mainly of elongated low hills. Towards the British Guiana-Brazil boundary, table mountains with vertical cliffs are found forming the ranges of Parima, Roraima and Pacaraima. General Geology The Guayana Highlands are the northern extension of the Brazilian Archean shield. Only a few scattered masses of sediments remain on its

Jan 1, 1935

By Richard R. Zupp, David A. Stevenson

A theoretical treatment of austenitic Fe-C-Z solutions (where Z represents a substitutional solute) was developed by extending a solution model which was previously applied to austenitic Fe-C alloys. The model assumes that each carbon atom in the solution excludes H interstitial sites from occupancy by other carbon atoms rmd thai otherwise the assembly of carbon atoms is equivalent to a modified Langmuir lattice gas. The results of the treatment provide theoretical justification for a phenomenological expression previously developed to represent the influence of substitutional solutes on the thernlodynamics of carbon in austenitic Fe-C-Z alloys. The expression is: where Kz is a parameter which characterizes the Fe-C-Z system at a given temperature and Xz and xj are the concentrations of substitutional solute and interstitial carbon expressed as atom ratios. The parameter, Kz, was associated with the differ- A number of investigators have measured the influence of various substitutional solutes on the carbon activity in austenitic Fe-C-Z alloys, where Z represents any substitutional solute. Experimental information is available for alloys containing the following substitutional solutes: Mn,' Si,' Ni,2-5 CO,'-', Cr,5, 9-11 CU,4 Al,= v,11, 12 and Ti.13 This information is essential for studying many phenomena in Fe-C-Z alloys, particularly diffusion and diffusion-controlled phase transformations For example the pffprts nf various ence between the interaction energies between carbon atorns and host-lattice atoms in the Fe-C-Z solution and the corresponding energies for the Fe-C solution. The carbon activity in a ternary Fe-C-Z alloy, ac, was obtained in terms of the composition of the alloy and the single parameter, Kz: where y° is the Henry's law constant for the binary Fe-C solution. Both y° and H crm be determined from the data for Fe-C solutions, without recourse to any experimental data for Fe-C-Z solutions. The theoretical treatment was extended to alloys containing several substitutional solutes. By neglecting interactions between the substitutional solutes, an expression for the carbon activity in multicomponent alloys was obtained in terms of the Kz values characterizing ternary Fe-C-Z systems. substitutional solutes on the rate of pearlite growth is explained14 on the basis of their effects on carbon diffusion, which result from their influences on the carbon activity in the solid phases. In addition, recent studies have emphasized the dependence of the pro-eutectoid ferrite transformation15 and other diffusional processes in austenite16 on the influence of substitutional solutes on the carbon activity in austenite. They have indicated the need for suitable analytical expressions to represent such influences. The present authors previously developed general phenomenological expressions to represent the equilibrium partitioning of carbon between Fe-C alloys and Fe-C-Z alloys.'2 The expressions are applicable to all the austenitic Fe-C-Z alloys for which experimental data are available, and are sufficiently simple to recommend their general application. For alloys in

Jan 1, 1969

THE BULOLO gold-dredging operations were described at some length by Frank W. Griffin at the Oct. 11 meeting of the San Francisco Section. This enterprise is on the island of New Guinea, about 1800 miles north of Sydney, Australia. The area in which the present placers exist originally was German territory but later the location was taken over by Australians. Gold was discovered in 1923 by prospectors who required 8 to 9 days to pack into the country over severe mountain trails. In 1926 a rich discovery was made on Edie Creek and in 1927 the deposit on the Bulolo River was discovered.

Jan 1, 1932

No. 373. Wanted.-Two mill and cyanide shift bosses who must be technically trained, thoroughly experienced along chemical and mill-operating lines. Must be energetic and of a caliber to take entire charge of mill in case of emergency and able to handle any technical questions that may arise. Plant consists of 400-ton stamp mill and cyanide plant. Working knowledge of Spanish desirable but not absolutely required. Salary $150 per month together with all other usual terms of regular contract. Location, Central America. No. 374. Wanted.-A University in the Middle West desires, for its mining department, a professor proficient in the preparation of coal and ores and mining design. No. 375. Wanted.-A University in the Middle West desires in its mining department a professor for a research position which requires not only a library and laboratory research man, but one who can mingle with, mine operators and technical men and labor men and represent the university technically in State work.

Jan 3, 1919

By D. K. Crampton

NEARLY everyone who has not had the benefit of study in the field of metallurgy subscribes to a persistent and enthusiastic belief in the legendary lost art of hardening copper. This of course supplies a perfect introduction to a chapter of information on copper and its alloys, since the dissipation of fallacies and superstitions affecting an art probably constitutes the best method of getting at its real substance. Metals are hardened, but also embrittled, by a plurality of impurities. In the modern technology of copper-base metal products, we are familiar with a great host of materials, passing from one extreme of dead soft copper better than 99.9 pct pure, which in the form of wire about as thick as a match will stand hundreds of full twists in a 12-in. length, to an alloy containing less than 3 pct of alloyed substance possessing the strength of pretty good steel and capable of manufacture into razor blades, should we suddenly be deprived of steel; certainly a much better material for this purpose. Every copper alloy known to primitive man lies in some inter- mediate position and the ancient bronzes that have been found all over the world wherever an early civilization existed are usually contaminated by such impurities as sulfur, oxygen, antimony, arsenic, iron, or other materials, so that they could not possibly conform to any modern intelligent specification insuring the best combination of useful properties in alloys of their type and would go

Jan 1, 1953

I AM sure, that you understand that of all the things created by the most high God Himself or by Nature at His command, not one-even though it be an atom or the smallest worm-has been produced without some particular gift. And if we do not always discern this in every thing, the cause lies in our defective vision, in our little knowledge, and in our lack of careful thought concerning the necessity of seeking hidden things. Certainly those things that have such inner powers, like herbs, fruits, roots, animals, precious stones, metals, or other stones, can be understood only through oft-repeated experience. [37] Others do not need so much knowledge and belief for their, powers are obvious and shown to us at all times by their effects. They reveal themselves to us through the sense of sight by their splendor and variety of colors, through the sense of smell by their odors, through the sense of hearing by the melody of the harmonious or unpleasantly discordant repercussions. of the air. They likewise manifest themselves by. their softness or harshness. As you see, all those things, according to. their limits, are conveyed .by the ordinary senses to the mind, by whose distinctions all their species, both harmful and beneficial, are discerned. Then they are reviewed by the judgment in all their degrees of perfection and imperfection, so that whoever seeks them with careful study or with experience often finds them. Now, in order to shorten this discourse, since I wished to speak to you of lodestone and its properties, I tell you that it is one of those things that show their apparent effects to our sight by a particular virtue hidden in such a way that its cause, as far as I know, has never been known to the very wise natural speculators who have spoken on every other subject. Thus one who considers its actions carefully must surely marvel, for it appears that Nature has put into this stone a certain spirit of vivacity, so that it seems to have-I would like to say-hands, although they are not seen. For I see that it not only attracts iron but also takes hold of it and keeps it attached to itself. This action is certainly great enough to bear certain witness to the virtues possessed by other created things that do not manifest their powers to the external senses. In order not to prolong this discussion, I tell you the following. This stone is found in various places and of different colors and properties. The

Jan 1, 1942

By Robert B. Sosman

THE chance that a Howe Memorial Lecturer will be able to refer back to a personal contact with the distinguished metallurgist for whom this lectureship is named grows steadily smaller. I did not have the pleasure of his personal acquaintance, but I did receive from him in 1916, quite unexpectedly, a letter commenting on a paper that I had recently published27 on "Types of Prismatic Structure in Igneous Rocks." The paper was written for geologists and petrologists, but it had an application, naturally, to the crystallization of iron and steel in a mold. The letter impressed me at the time, and still does, with the breadth of Professor Howe's interests and his perseverance in keeping up with the progress of any branch of knowledge that had metallurgical connotations. SCOPE OF THE LECTURE During several years preceding the date mentioned I had worked in collaboration with Arthur L. Day and E. T. Allen8 at the Geophysical Laboratory, Carnegie Institution of Washington, on the temperature scale as defined by the nitrogen thermometer at high temperatures. Later (1928-1947) I had the opportunity of helping to apply this experience to the pyrometric problems of the steel industry. Because of the range of its temperatures, the multiplicity of the methods used, and the variety of its purposes, pyrometry in the open-hearth process has always offered a fertile field for both research and development. I am therefore devoting an hour to the subject of temperatures in the basic open-hearth furnace, the furnace that makes most of our steel in the United States. I would direct your attention particularly to the choice of the first two words in the title of the Lecture. One sometimes hears or reads of the "temperature of such-and-such a furnace," as if it were a single, measurable, characteristic quantity. I need hardly emphasize to any one who has ever operated a furnace or a kiln that "temperature of the furnace" is a meaningless phrase. Even if we confine our attention to the space enclosed by the roof, walls, and hearth of an open-hearth furnace, it is doubtful whether any such space has ever been so uniform in temperature that the phrase would have a meaning. In any furnace, there are many different temperatures, capable of being measured at many different places, and actually being measured for several different purposes. These pyrometric purposes, methods, and results, if given in detail, would expand this lecture into a book on the basic open-hearth process. I must therefore confine myself to a statement of the range of temperatures as they have been observed in various parts of the furnace, indicating in a general way why they are measured, and mentioning the methods that are available without attempting to describe these

Jan 1, 1948