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By V. H. Gottschalk, R. S. Dean

In the theoretical study of metallurgical reactions, it is necessary to make certain assumptions concerning the nature of metal-gas systems. The assumption usually made is that the reaction in such systems takes place predominantly with gas that is in "solution" and that the amount of solution follows the rules which have been developed for aqueous solutions; namely, Henry's law. The purpose of this paper is to inquire whether these assumptions are the best ones that present knowledge of gas-metal systems permits us to make. In the first part the extent to which a gas will dissolve in a metal and still follow Henry's law is considered. The conclusion is believed justified that the number of molecules of gas that can dissolve in a metal and have the system follow Henry's law must be small indeed. It is therefore improbable that the first assumption concerning the predominance of these dissolved molecules in reaction is correct. It is suggested that some improvement in the correlation of the probabilities with the assumptions made in the mass law equations would be made by the use of the dp law of Sieverts in place of Henry's law. However, the amount of gas that may be held in a metal so that it follows either Henry's or Sieverts' law is considerably outweighed in most metallurgical reactions by that held in gas-metal systems of entirely different structures and concerning which little experimental evidence is available. Some speculation concerning the nature of these is offered. The conclusion is that attention should be given to the determining of the nature of gas-metal systems and that the really fruitful application of the mass law and its connected calculations will have to await a more complete knowledge of these systems than we now possess. DISCUSSION (Paul D. Merica presiding) P. D. Merica, New York, N. Y. (written discussion).—The solubility relations of gases in metals, in so far as they are known from the pioneer work of Sieverts and others, have from the first presented certain challenging peculiarities. The authors have emphasized the significance of these characteristics and suggest that they point

Jan 1, 1933

By D. Turnbull, J. H. Hollomon, J. C. Fisher

The concepts of nucleation and of growth have adequately described the isothermal phase transformations to which they have been applied.ls2 However, these concepts have not yet been used successfully to describe the kinetics of a number of transformations that are not observed to take place isothermally. A typical reaction of this type is the austenite to martensite transformation in steels, for which the new phase appears only during cooling of the parent phase. If the cooling is interrupted, transformation ceases; yet had the cooling continued, transformation would also have continued. Nuclei of a new phase do not leap into existence all at once by the simultaneous cooperation of a large number of atoms or molecules of the parent phase; rather they are formed at finite rates by gaining or losing atoms one at a time from the surrounding materiaL3,4 Further thermo-dynamic considerations require a finite concentration of small transitory nuclei of all unstable phases to exist at equilibrium in a stable phase.= For steel in particular, nuclei of ferrite (a iron) exist at equilibrium in austenite (y iron) at temperatures where austenite is the stable phase. If a high-temperature phase a be cooled sufficiently rapidly from temperature TI above the a-ß equilibrium temperature To, to temperature T-1 below To where ß is the stable phase, the equilibrium distribution of ß nuclei corresponding to the high temperature will be retained. There are two limiting possibilities of particular interest: I. The steady state rate of nucleation of ß may be appreciable at T_1, and may require a concentration of sub-critical nuclei exceeding that retained from the high temperature. Time will be required then for the concentration of nuclei to build up to the steady state value, and an induction period will be observed during which the rate of nucleation will increase to the steady state value. 2. The steady state rate of nucleation of ß may be negligible at T-l, while the critical size for continuous growth of ß nuclei, which decreases with increased subcooling of the a phase, may reach a value so small that some. of the retained high-temperature nu-

Jan 1, 1949

By Best W. N.

Discussion of the paper of W. N. BEST, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1527 to 1537. WILLIAM A. WILLIAMS, San Francisco, Cal.-I would like to ask whether .Mr. Best ever had any experience with an oil burner that used neither air nor steam? W. N. BEST, New York, N. Y.-Yes. This type is commonly known as the "mechanical spray burner" and uses oil heated under high pressure to above its vaporizing point. These burners are not as efficient as the atomizing type for the following reasons: 1. They produce a round flame which; as with any other type of burner, must pass over a flat surface. A round flame cannot fit a flat surface. 2. They do not evenly distribute the heat, resulting in localized heat. 3. The outlet through which the fuel passes is very small; so all gravities of oil, especially oil containing sand, cannot be burned. 4. Their construction is such that they must be cleaned frequently, as the residuum in the fuel clogs the burner. 5. The oil opening being small, the capacity of each burner is small, so that many burners must be used in a boiler or furnace. (The fewer burners there are, the more accurately they can be regulated.) In marine boilers, these burners are largely used, because they do not require either steam or air for atomization. However, there are other methods by which this objection to other types can be eliminated, such as by the use of a rotary blower and steam turbine engine, the exhaust front the engine passing into the engine condenser, thus obviating loss of water. Mechanical burners are rarely used in shops. I know of but one power plant using them. With mechanical burners, the fuel must be maintained at a high pressure. On board naval vessels, some mechanical burners demand an oil pressure of from 100 to 6001b. It is advisable to reduce the pressure as much as possible, as fractured pipes or fittings are particularly dangerous, for the heated oil escapes as a vapor. In such cases there is liability of an explosion caused by spontaneous combustion.

Jan 12, 1915

Discussion of the paper of F. M. Simonds and E. Z. Burns, presented at the New York Meeting, February, 1913, and printed in Bulletin No. 75, March, 1913, pp. 369 to 402. W. L. SAUNDERS, New York,. N. Y.:-Mr. Burns in his native Colorado modesty has said that he apologizes for things left out of this paper. I am much impressed by what he has put into the paper, as of all the papers that I have read on the subject, describing, as it does, a specific piece of work that has been accomplished, I do not recall one that gives so much information in such a practical way. Mr. Burns has also said that it is very hard to get men to put things down while the work is being driven. My experience is that it is very much harder to get the men in charge of work of this kind to bring them in in the form of a report before a body of engineers after the work is done. We have a great many cases where records are kept in much detail, but they are usually kept under cover, with the mistaken idea that the information gained is private information for the benefit of those who have done the work. Messrs. Simonds and Burns have opened up this case so that we can get the benefit of that experience which they have had, and so that we can learn something for the future. The description contained in this paper, as I have said, is a very practical one. You will notice in going through it. that the authors have given in detail a record of their work from the beginning to the end, and they even go so far as to publish an exact copy of the Rawley Mining Co.'s daily report. That daily report is something which those of us who are engaged in similar work might copy to great advantage, and having it before us we can check up our men while doing work and exact from them equal conditions, if it is possible to do so.

Jan 5, 1913

W. E., RUDER, Schenectady, N. Y. (written discussion *).-Professor Howe, with characteristic thoroughness, has demonstrated that Professor Jeffries' "Reversed Inheritance" explanation of the case in question is contrary to fact, as shown by many previous observers. Since the photographs were my own, I feel it my duty to say a few words in discussion. In the first place, it is to be noted that these photographs were of pressed powders, and although many of Professor Jeffries' original experiments were made from this kind of material, the nature of such a specimen must of necessity be different from that of the fused metal, although the same basic laws of grain growth may apply in both cases, certain factors, such as the rate of change, for example, are undoubtedly different in each case. That the 1000° C. grain is a natal grain is evident from its appearance contrasted with the more perfectly formed, though smaller, grains in the 1300° C. photograph. I am not sure that Professor Howe's explanation of the formation of this grain is necessarily the correct one, although it agrees with. Stead and Carpenter's results. I am inclined to think that this grain may have been formed on heating, because I have been able to produce grains of the shape and magnitude of Stead and Carpenter's grains by heating to 850° C. pure electrolytic iron, which has been subjected to a strain gradient. On reheating to 1300° C., the mobility being so much greater, the individual crystals had time for unhampered re-arrangement and growth after their second refinement on passing Ac3, so that we have in this case a true fused metal condition in which the individual crystals are arranged in true equiaxed grains of a size consistent with their high temperature anneal. In this case the grains are equiaxed, inheriting none of the columnar tendencies of the previous grain, because they were not affected by any strain gradient, except possibly some accidental local gradients. It seems to me that the introduction of pressed powders into the discussion of grain growth, where allotropic changes take place, unnecessarily complicates an already complicated problem.

Jan 1, 1918

Discussion of the paper of F. C. LANGENBERG and R. G. WEBBER, presented at the New York meeting, February, 1915, and printed in Bulletin No. 98, February, 1915, pp. 291 to 300. HENRY M. HOWE, Bedford Hills, N. Y.-The results here given are of great interest and are welcome as forming another rivet to increase the stability of our present theories of the constitution and properties of steel. The important discovery is that the hysteresis increases with the fineness of the structure, that is to say with the extent of contact between the particles of ferrite and cementite. All of the specimens except No. 4 consist of ferrite and cementite of different degrees of intimacy of admixture. If hysteresis represents something akin to surface friction, which retards the rotation of the ferrite on the application and release of the magnetizing force, then it is only natural that it should increase as it does with the intimacy of admixture, because it is at the surface of contact of a given particle of ferrite with the neighboring particles of cementite that this friction is to be expected, and of course the extent of surface must in¬crease with the intimacy of admixture. The somewhat greater hardness of specimen 4 than of the others may perhaps he referred to the principle discussed in my paper, Why Does Lag Increase with the Temperature from Which Cooling Starts?' The furnace-cooled specimens were cooled so slowly that the influence of the initial temperature of heating is effaced. But in the air-cooled specimens we have the suggestion that the high temperature, 1,000°, from which the cooling of No. 4 started has prevented the completion of the transformation, with the result that the metal is slightly harder than any of the others. The difference is not to be explained by difference in the fineness of structure, because the whole range of fineness from No. 1 to No. 6 is accompanied by no change in hardness, the only change being an appreciable increase of hardness following the air cooling from 1,000°.

Jan 5, 1915

By Carl Zapffe

JUST as 85 per cent of the total ore produced annually in the United States comes from the Lake Superior region, so does one of its six producing districts-the Mesabi --dominate that region both as to production and total reserves; also in ore Treatment, Mesabi practice is dominant. Therefore, in discussing future reserves or ore treatment one may visualize one big district with five smaller districts as so many satellites. In considering the future less thought need be given to processes than to, economic policies. For thirty years experimental work has now been in progress and every possible ore-treatment process now known has been given attention. This work was started when there was no recognizable danger of running short of ore because of rapid consumption. Thirty years ago the annual production had just progressed beyond the twenty-million bracket for the first time. Today fifty million tons is considered a small production, and last year the aim was for 65 million. At the recent rate of production the life of the estimated reserves of good ore is about 35 years. All who know the local terrain are convinced that, unlike thirty years ago, the chances for discoveries of new big deposits are nil; treatment of lean ores obviously is to become an all-important topic.

Jan 1, 1938

By James E. Harding

AT just about the geographical center of the peninsula of Lower California is the El Arco gold mine. It is small and spotty, and three separate attempts to operate it in the past have failed. The only reason the present operation is possible is because of the higher price of gold and because the previous operators had spent about $300,000 developing the property with shafts, four levels, machinery, and a complete mill, all of which was acquired at a bargain price. All the known ore in the mine, to say nothing of the cost of recovering it, is

Jan 1, 1937

By F. X. Meyer

THE United States Smelting Refining and Mining Company maintains an ore-purchasing department for procurement of custom tonnages of milling and smelting ores and concentrates for treatment at its Midvale plant. Arrangements with other companies provide for treatment of Company and custom zinc concentrates. Location of the Midvale plant in the heart of the Western mining country makes it possible to serve shippers from these nine producing states: Arizona, California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, and Washington. Shipments from most of these states travel over main-line railroads, delivery being made at Midvale within a short time after billing of the shipment. Shipments varying in size from a few sacks to carloads can be handled at

Jan 1, 1948

By Oscar A. Glaeser

MINE VENTILATION is an important factor in mine maintenance as well as having direct bearing on labor efficiency. Effective ventilation systems are costly, especially those for the deeper mines, but with intelligent direction the worth of a system is usually greater than its cost. In most mines using mechanical ventilation, and practically all deep mines, it has been found beneficial to equipment, timber, and the ground, to run the fan or fans continuously even though production has been curtailed or entirely suspended. Therefore, economies in ventilation may be overlooked when general cost reductions are necessary. The operating costs of a well-designed ventilation system should be capable of reduction during periods of curtailed or suspended operations. A mine that is ventilated by splits, or that can be sectionized, can reduce its fan-power costs considerably, and provisional divisions can sometimes be made in other mines, in which the air is ordinarily coursed through all the workings, without harmful effects.

Jan 1, 1932

By Raymond O. Ladoo

FUSED quartz is a glass made by the fusion of nearly pure silica. Some confusion in terminology exists but in the trade today "fused quartz" generally refers to the perfectly transparent colorless product made from rock crystal whereas "fused silica" is a white, translucent product made from silica sand. Vitrified silica is the term preferred by purists for all quartz glass, but it lacks the definiteness of -the trade terms. Since the raw materials, methods of production, and properties of the finished products arc different for the two types, the trade terms are preferred. As fused quartz is amorphous, it-physical properties differ greatly from those of quartz crystal. Lacking crystallographic directions and having no piezo-electric properties, fused quartz. of course, has no value for the making of radio oscillator plates; but it does have other valuable and unique properties. Perhaps the 'best known and most useful properties are its extremely low coefficient of expansion and its ability to transmit short-wave ultraviolet radiant energy. Crystal quartz not only has an aver-

Jan 1, 1947

By H. E. Kramm

(New York Meeting, February, 1919.) DURING the summer of 1911, I had the opportunity to study in detail the geological conditions of what is known in northern California as " Harrison gulch," in Shasta county. Though the district, as a whole, that is, the western part of Shasta and the eastern part of Trinity county, has contributed during the last 15 years a considerable share of the gold-production credited to Shasta county, very little is known of its geology, perhaps because the country is covered with a dense growth of brush which makes exploration and prospecting extremely difficult. Topographically the district presents a succession of ridges trending approximately N-S.; and alternating with deep narrow canyons. The drainage is partly into . the Sacramento, partly into the Trinity river. Climatic conditions in summer time are almost ideal. It is true, the thermometer may climb to 115°, but the air is dry and the heat is bearable, especially as the nights are always cool. It seldom rains during the summer months, and creeks and springs dry out towards the end of the summer. The winter is severe, lasting from November to April, and usually a thick layer of snow covers the mountains. By reason of the character of its gold-deposits, the region is known to miners as "the pocket country." It contains a series ?of eruptive rocks intruded into slates, cherts, limestones, and conglomerates. Dikes, laccoliths, and batholiths are frequent. In a day's ride it is possible to find all the common igneous rocks from the very acid to the very basic. Serpentines are especially abundant.. The sedimentary rocks are, as rule, broken and shattered as well as folded, and show the effects of intense metamorphism. ? Pocket-hunters " speak of the contact of diabase and slate as the ? pocket-contact." Some rich gold-pockets, however, have also been found in the diabase.

Jul 1, 1912

By E. H. Sellards

ON Oct. 9, 1929, a sink formed in the Sour Lake salt dome oil field in Texas, and on Oct. 12 a second smaller sink formed at the north margin of the first. The purpose of this paper is to give such observations as it has been possible to make on the earth movement incident to this subsidence. Sour Lake salt dome is typical of the salt domes of the Gulf Coastal Plain of Texas. Structurally the dome is a plug of salt which rises to within 900 ft. or less of the surface. Above the salt is a cap rock consisting of anhydrite with more or less calcium carbonate. The salt plug, as contoured on the cap rock, is circular in outline with, however, some appreciable irregularities. Overlying the cap rock are relatively uncompacted sediments consisting of sand, clay and gumbo.. At the crest of the dome these deposits are no more than 700 or 800 ft. thick. However, the sides of the dome are steep, and the sediments thicken rapidly away from the crest. The sink formed about 1500 ft. northeast of the crest of the dome where the sediments overlying the cap rock are from 1000 to 1200 ft. thick. The cavity permitting the subsidence was quite certainly either in the cap rock or in the salt below the cap rock, so that the sink was formed by the caving of as much as 1000 or 1200 ft. of earth.

Jan 1, 1930

By J. F. Myers

AT the Regional meeting in Columbus, Ohio, in September 1949, the authors presented a progress report of the first year's operation with a Hardinge tricone mill in closed circuit with a Dorr hydroscillator. The present report covers our findings on this grinding circuit to January, 1950. In order to clarify our position, the authors wish to state that no invention or discovery is claimed. The Tennessee grinding circuit is simply an engineered arrangement of known equipment arranged to incorporate all of the recognized efficiency factors of comminution as they are known today. As we concluded our first report, it was not clear how effective the Tennessee mode of operation would be on harder ores. The only information we had at that time was that the Bond grindability test at 48-mesh gave 6.04 g of undersize per revolution. A later test on the same sample at 100-mesh reduced this to 2.04 g, which is definitely in the harder ore class, and which makes the reported 8.80 kw-hr per ton of -200-mesh produced a very creditable figure.

Jan 1, 1950

By F. L. Clerc

THE lead and zinc region of SW. Missouri is interesting, not only by reason of the value of its output, which ranges in the neighborhood of ten million dollars a year, but even more because of the facilities which it offers for the study of certain forms of ore-deposits, of which the loci and genesis are somewhat obscure. Although the mineral species found in the region are few and of common occurrence, crystallization has taken place on a generous scale, and unusual forms abound in many combinations, presenting examples of pseudomorphism, paragenesis, metasomatic replacement and the action of mineral-depositing and mineral-dissolving waters. For the mineralogist, lithologist, and specialist in certain lines of metamorphism, it has peculiar attractions, while the systematic geologist will perhaps find its chief claim to attention in the simplified problem it presents, in the study of ore-deposits. In addition to the phenomena above enumerated, it presents instances of well-developed comb-structure in the ores, fissures and faults, and slickensides-features usually associated with extensive movements in the earth's crust, and believed by some authorities to prove the deep-seated origin of the ores. In connection with these occurrences, the absence of all igneous rocks from this region is noteworthy and significant. For that reason, the simplified case presented by the Joplin region, from which these rocks have been eliminated as a factor, is specially valuable. Having had unusual opportunities to watch the development of this district, I have been deeply interested in the bearing of the revelations of the Joplin mines upon questions of universal importance to the science of ore-deposits ; and it was to my great regret that the project of a meeting of the American Institute of Mining Engineers at Joplin, proposed in 1892, was

Mar 1, 1907

By W. L., Yerkes

AN interesting study of the application of air-, conditioning to the problem of mine ventilation and cooling can be found on the Witwatersrand in South Africa. Here there are a large number of deep mines in a relatively small area. Due to the nature of the reef, many mines are working at a depth of 6000 ft. and some have gone down to 8000 and 9000 ft. below the surface. At such depths, even in a country geologically as old as Africa, the virgin rock temperature approaches 110°F. The flow of heat from the- rock to the ventilation air is tremendous though the shaft or drift may have been open to ventilation for some years. In addition, there is the heat produced by machinery, lights, and men at work and the heat of adiabatic compression of air introduced into the mine. The difference in atmosphere pressure between the collar of a shaft and a level 6000 ft. below is nearly 3lb. per sq. in., resulting in an increase in heat content of nearly four B.T.U. per pound of air delivered to the mine at surface. Further the exclusive use of wet mining to reduce the incidence of miner?s phthisis increases the latent- heat content of the air.

Jan 1, 1941

By William L. Saunders

MANY members of the Institute, who participated in the visit made, during the Bethlehem meeting of February, 1906, to the shops of the Ingersoll-Rand Company, at Phillipsburg, N. J., inspected with interest the new Electric-Air drill, which the company had set up for the purpose of showing it in actual operation to American. mining engineers. At the request of the Secretary of the Institute, I promised at that time to prepare a paper for our Transactions, describing the construction and advantages of the machine. But such a paper would then necessarily have contained much that was only expected or claimed by the designers and manufacturers of the drill, and not yet incontrovertibly proved by varied and long-continued practice. However moderate such statements might have been, they would have given inevitably to the paper, to some extent at least, the air of a prospectus, rather than of a technical contribution. I therefore decided, with the Secretary's approval, to postpone the writing of the promised paper until it could set forth the results of adequate actual practice, as well as the latest details of construction, etc., based upon practical experience. That period has now arrived. The Electric-Air drill has been exhaustively tested in the field, under varied and arduous conditions and upon the hardest rocks. It is now fairly in the field; its merits and performances are matters of unimpeachable record, and its place among established competitors can be definitely determined. As a representative of the Ingersoll-Rand Co., as well as a member of the Institute, I may be permitted to add that my company, being largely interested in the manufacture of air-

Jan 9, 1907

By Dean, R. S.

THE numerous theories of hardening which have been advanced in recent years are all satisfactory in accounting for some of the phenomena observed in hardening metals, but none so far presented account for all of the facts observed. Some years ago one of the authors, R. S. Dean,' presented a theory to account for some of the properties accompanying work hardening. The present paper develops this theory further in the light of recent experimental work and extends it to other forms of hardening. Many of the ideas included have come from the writings and personally communicated thoughts of others. We have attempted to give proper credit in every case, but it is possible that we have not always done so. As an historical basis it is desirable here to review very briefly the hardening theories which have been current. The first comprehensive theory of work-hardening phenomena was due to Sir George Beilby.2 He contributed the idea that with cold work part of the structure of the metal was rendered amorphous and that-it was to this amorphous material that the cold-worked metal owed its difference in properties. According to Beilby's theory this amorphous material was a supercooled liquid and, therefore, had the characteristics of a vitreous material. That such a theory is not capable of explaining the property changes in metals has been repeatedly pointed out. This theory also allowed a slip to take place only once on a given plane, which, as has been pointed out by Jeffries and Archer13 is not consistent with the observed length of an, individual slip and the amount of elongation which can be obtained by wire drawing. The modifications, which have been proposed to this hypothesis to make it coincide with the experimental facts, have to a considerable extent robbed the theory of its clean-cut characteristics. The commonest of these modifications replaces the amorphous phase with an

Jan 1, 1927

By E. R. Kaiser

COAL research during 1941 had a marked increase in activity on problems bearing directly on furthering the increased and improved use of coal in homes and industry. Coal producers and fuel engineers expressed a greater interest in its practical possibilities and the coal laboratories have shown an increased interest in applied research, of value at once or in the near future to industry and the public. A large volume of accomplishment in mining, coal analysis, and the fundamentals of coal constitution and coal chemistry also continued to fill the storehouse from which applied research and fuel engineering of the future can draw valuable data.

Jan 1, 1942

By Daniel Bloomfield

ONE of the major problems of management is how to restore in some measure the personal relation-ship between employer and employed which, in the days of small concerns, meant better morale among employees. The complexity of industry today, the heterogeneous mass. of workers employed, many .of them new to this country and to its institutions, the inability of those whose task it is to get out production to spend much time on the problems of labor-all these and many other factors serve to make of great impor-tance the question of how to establish more satisfactory mutual good will. While there is no such thing as a sure cure for labor troubles, in spite of the fact that charlatans have been selling alleged cures to guileless employers, study and experience have brought to light methods of approach to the problems confronting management in its relation to labor that are well worth consideration. Labor problems must be approached with common sense and an open mind. Facts must be the basis of action. So it is with the question of morale in industry. What makes or breaks morale? What are the forces behind the actions of men? What is there in one man that makes him act differently from another man under similar circumstances? How are men affected by the actions of others in their own group or by the actions of those under whose supervision they work? These are questions that must be carefully studied if we are, to get at the bottom of industrial unrest. It is an easy thing to say that good will can be created by "treating men right." That involves so many things and points of view that it will hardly serve as a full answer to our problem; but it is a good starting point if we mean by right treatment the payment of wages consistent with the well being of the worker and his family as members of the community, and if we also mean the provision of sanitary, wholesome working conditions and a working schedule that does not overtax the worker physically, and mutuality-a give and take relationship. With this as a basis we can go a step farther and see what else can be done to promote better relations between management and the workers.

Jan 9, 1922