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By Ernest L. Ohle

The newly opened Hayden Creek lead mine represents a variation from the usual Southeast Missouri type. Galena mineralization occurs in sandy dolomite cementing a conglomerate of granite boulders and in cracks in the boulders. The conglomerate occurs at the base of the Bonneterre formation on the slopes of two buried pre-Cambrian knobs. IN 1943 diamond drilling from the surface in an area 2 miles southwest of Leadwood, Mo., discovered a lead deposit of a markedly different character from the usual southeast Missouri type. Subsequent drilling of about 500 holes indicated several million tons of ore, and in 1950 a 701-ft vertical shaft was sunk into the orebody. This paper describes the geology of this interesting occurrence insofar as it is known from the drilling and the small underground exposure at the bottom of the shaft. Geology The location of the Southeast Missouri Lead Belt and of the Hayden Creek property are shown in Fig. 1. As shown here, there are two separate producing areas, one from which the larger tonnage has come, located near Bonne Terre, Flat River, Desloge, and Leadwood, and the other to the south around Fred-ericktown and including famous old Mine LaMotte. The best published description of Lead Belt geology is by Tarr.* In pre-Cambrian time in this area, an assemblage of granites and rhyolitic flow rocks was eroded to a mature topography. Sedimentation, beginning in the Upper Cambrian, filled in the valleys and gradually covered even the highest hills. The first formation deposited was the La-motte sandstone; it is successively overlain by the Bonneterre dolomite, the principal lead-prodbcing formation, then the Davis shale. the Derby-Doerun limestone, and a succession of Cambro-Ordovician cherty dolomites. Several of these formations may be found in direct contact with the pre-Cambrian as their deposition progressively overlapped the older rocks on the flanks of the igneous knobs and ridges. Immediately overlying the pre-Cambrian there is, not uncommonly, a thin basal conglomerate of granite or porphyry boulders, which is incorporated into the overlying sediments. Deposition of the lower part of the rock section was fairly continuous, and the Lamotte sometimes grades almost imperceptibly into the lower sandy Bonneterre. Since the sediments were deposited on an uneven floor, they tend to reflect the irregularities in that floor. Most of the steep dips found in the district, that is, dips in excess of 10°, are original dips and not caused by deformation. Such domelike structures in the sedimentary rocks around the igneous knobs have localized a considerable number of the orebodies in the district and particularly those in the Frederick-town area. Many of the larger orebodies, however, have no close relation to the pre-Cambrian topography. Most of the lead production has come from the lower 150 ft of the Bonneterre formation, where disseminated ore spreads laterally parallel to the bedding for great distances. Average stoping height is about 20 ft, but in a few places there are stopes over 175 ft high.

Jan 1, 1953

By L. R. Shoenberger

Boron has been used to produce nonaging low-carbon sheet steel. Retention of the necessary minimum amount of about 0.006 pet partially killed the steel. Amounts exceeding about 0.012 pet increased the degree of deoxidotion, piping tendencies, and possibility of hot tearing in primary rolling. Semikilled practice resulted in good ingot yields and satisfactory surface quality. Aluminum added with the boron provided a protective de-oxidizer. Good drawobility was indicated by performances of the steel in a limited number of deep-drawing trials. Some problems with hot-tearing and boron-analysis procedures were overcome. Metal lographically, the boron semikilled steels revealed some structures not usually found in plain low-carbon steels. IN 1943 Low and Gensamer1 reported that strain aging, which hardens and embrittles ordinary low-carbon rimmed steel, was due to nitrogen and carbon, and that oxygen played a relatively unimportant role. Since then, many investigators have substantiated their findings and indicated that nitrogen is particularly potent. Commercially, today's most widely produced non-aging sheet steels for deep drawing are either aluminum killed or vanadium rimmed types. The difference in deoxidation practice, alone, is evidence that oxygen is apparently not an important consideration in control of strain aging. The fact that nitrogen is important is apparent in the consideration that has been given, knowingly or unknowingly, to the amount combined with aluminum and vanadium. Patents were granted to Hayes and Griffis2 for the processing of aluminum-killed steel, and to Epstein" for the manufacture of vanadium rimmed material. Certain prescribed steps in producing these steels can be correlated with the formation of the respective nitrides within certain temperature ranges below the usual hot-finishing temperatures. The potential nonaging properties of either type can be reduced or suppressed by cooling too rapidly to permit the aluminum or vanadium to combine with nitrogen. Subsequent suberitical annealing of the cold-rolled strip, however, normally forms the nitrides and produces the resistance to strain aging. Titanium-killed nonaging steel, described by Comstock,1 forms a nitride in the molten state and is essentially nonaging throughout its processing. Zirconium-killed steel, which was investigated briefly by the author,* appeared to have similar nitride- forming characteristics. It is known" that chromium can produce nonaging rimmed steel, but relatively little is known of the potentialities of some of the other nitride-forming elements such as boron, silicon, columbium, and cerium. In attempting to develop a new nonaging cold-rolled sheet steel with good drawability, the following factors were considered pertinent. Such a steel would necessarily have a low carbon content and therefore have a relatively high degree of oxidation when made in a basic open-hearth furnace. If the denitriding element were also a deoxidizer, a part of the addition would be lost as oxide. The degree of deoxidation would determine whether the steel is rimmed, semikilled or killed, and also could be expected to have an important bearing on ingot yields and ultimate surface quality. Assuming that the pattern for the production of cold-rolled sheets would not be changed to any great extent, the nitride must form in the molten steel, in hot rolling, in subsequent cooling, or in annealing. The nitride, once formed, should resist dissociation and be stable in the final product. Usually an excess of the nitride-forming element is required to combine with sufficient nitrogen. If the element used is a strong ferrite strengthener, a small excess may markedly decrease drawability. With aluminum and vanadium, about 0.03 to 0.05 pct in the steel is preferred. Epstein has said" that about 0.30 pct chromium is required. Titanium nonaging steels are hard unless a sufficient amount (about 0.30 pct) is added also to combine with the carbon. The cost of the necessary amounts of these latter two elements discourages commercial acceptance. Silicon was considered as a possible nitride former, but since amounts up to 0.10 pct in rimmed and semikilled steels do not induce marked resistance to strain aging, larger amounts are apparently required, which would tend to harden and strengthen the ferrite. Of the other elements mentioned, all but boron are expensive heavy-metal elements. Stoichi-ometrically, almost an equal weight of boron would be required to combine with the nitrogen—-ordinarily about 0.003 to 0.006 pct in scrap-practice open-hearth steels. Boron is a slightly stronger deoxidizer than carbon but is less powerful than zirconium, aluminum, or titanium. Thus a rimmed-steel practice might be possible. There is much in the technical literature concerning the hardenability effects of minute amounts of boron in killed steels but very little about its behavior in low-carbon material—particularly as a ferrite strengthener. The available data indicated a need for better information concerning the effects of boron in low-carbon strip steels. Experimental Work Development of a Boron-Treated Nonaging Strip Steel—Initial attempts to produce a boron-rimmed strip steel employed 3-ton basic open-hearth heats which could be teemed into molds large enough to sustain a normal rimming action. Boron as ferro-boron was added to the ladle in small amounts because of the reported hot-short character of aluminum-killed heat-treating grades containing more than about 0.005 pct boron. Actually, the amounts used, i.e., 1/8 and 1/4 lb per ton, would be large for

Jan 1, 1959

By I. R. Kramer

I. R. Kramer (Martin Co.)—In a recent paper Nakada and Chalmers24 reported some observations of effects of surface conditions on the stress-strain curves of aluminum and gold single crystals. It is of interest to compare these observations with the results published previously in this journal and to comment on their general conclusions. In brief, Nakada and Chalmers concluded that the removal of the surface layer of a prestrained specimen lowered the stress-strain curve for aluminum but not that for gold. Further, they concluded that the surface work hardening of aluminum is confined to a depth not more than l0-3 cm. In our results25 published previously, it was pointed out that when prestrained specimens of aluminum and gold were polished to reduce the thickness upon reloading the initial flow stress decreased markedly. Further if a sufficient amount of metal was removed, the yield point failed to appear. With continued application of the load the stress-strain curve became coincident with that of the virgin crystal. We have found this behavior in some 100 determinations to hold consistently for gold, aluminum, and copper in both single and poly-crystalline specimens. The amount of strain required before the curves coincided depends upon the amount of metal removed but it is usually less than 0.01. This type of behavior is the same as that reported for metarecovery by other investigators.29 For aluminum specimens which have been prestrained and then heated to temperatures above 50°C we have consistently found that the stress-strain curve was typical of the orthorecovery28 type. In this case the stress-strain curve always lies below that of the virgin specimen. With respect to Ref. 24 the curves for aluminum are always below that of the virgin curves, while those for gold become coincident. This observation indicates at least for aluminum that the specimens must have been heated to a temperature high enough to cause recovery by an alteration of the internal dislocations. In addition, a recovery would be expected because of the removal of the surface work-hardened layer. Nakada27 had reported that, with his particular apparatus in which a perchloric acid polishing solution was used, the temperature of the specimen increased 65°C. The curves presented in Ref. 24 for gold do not permit one to detect the initial flow stress upon reloading after the surface-removal treatment. In fact, contrary to the method used by Nakada and Chalmers, the change in the stress-strain curve produced by a surface-removal treatment cannot be described in terms of a decrease in stress at strains much higher than that at the initial flow stress because of the coincidence of the curves at the higher strain values. With regard to the depth of the work-hardened surface layer, our data show for aluminum single crystals (7.5 by 0.3 by 0.3 cm) that the initial flow stress remained constant after 12 x 10-3 cm had been removed from the thickness. This depth was independent of the prior strain. For gold crystals this depth is somewhere between 10 x 10-3 and 20 x 10-3 cm. Y. Nakada (author's reply)— Kramer states,28 "for aluminum specimens which have been prestrained and then heated to temperatures above 50°C, we have consistently found that the stress-strain curve was typical of the orthorecovery28 type. In this case the stress-strain curve always lies below that of the virgin specimen." However, Cherian et a1.26 discovered that aluminum polycrystals annealed at 32" and 100°C showed the metarecovery behavior. They showed that the orthorecovery behavior did not appear until the crystals were annealed at 150°C. Kramer suggests28 that the drop in the flow stress of aluminum crystals after the surface removal by electropolishing24 may be due to the recovery caused by the temperature rise which may occur during the electropolishing.27 However, as indirectly stated in Ref. 24, the current density used in these electro -polishing experiments was 0.15 amp per sq cm. According to ref. 27, this current density should cause a temperature rise of only 40°C. This may cause the metarecovery but not the orthorecovery. Furthermore, as stated explicitly in Ref. 24, the surface removal was accomplished by chemical etching as well as by electropolishing. The results were the same for both electropolishing and etching. During the etching, the specimen temperature did not rise above 35°C. Some aluminum crystals were placed in water at 35° C for 30 min. These crystals did not show the decrease in flow stress. Therefore, it is quite clear that the flow-stress drop after the surface removal is not caused by a high-temperature recovery. However, as Kramer points out,28 it is quite possible that the internal dislocation structure may have been altered because of the removal of the highly work-hardened surface layer. However, how much this rearrangement contributes toward the flow-stress decrease is not known at present.

Jan 1, 1965

By Roland J. Lapee

A history of the progress made in copper refining in Montana is presented. The casting furnaces and the newly rebuilt electrolytic refinery are descmbed and operating details are given. Experiences with various addition agents, effects of rernoval of chlorine from the electrolyte, and effects of separan on electrolyte and on copper deposit are discussed. Observatzons are made on the effect of various impurities in anode copper and behavior of thezr salts in electrolyte and in slime, on treatment of slime for removal of copper, and on electrolyte puriification problems. The improved method for production of starting sheets is described. Attention is given to new materials for construction and to improvement in matrials handling ad quality control. COPPER refining at Great Falls, Montana, dates back to 1892. The original plant produced 65,000 lb. of cathodes per day at a current density of 16 amp per sq ft. In this plant anodes and cathodes were handled to and from the cells by means of hand-operated chain blocks and were moved about the plant by hand trucks. Cathodes were melted in coal-fired, reverbera-tory furnaces, were charged by hand, and refined copper was dipped by hand and cast in iron molds. In 1916, a new, modern plant with capacity to refine 18 million Ib. copper per month was built. Two refining furnaces were built, and each was provided with a twenty-mold Clark casting wheel. In 1922, the furnaces were converted to the use of pulverized coal: in 1923, to the use of oil; and in 1928, to the use of natural gas. In 1926, the plant was enlarged 50 pct. The use of pulverized coal for refining copper at Great Falls was discussed1 in a paper presented at the Salt Lake City meeting of the Institute in September 1925. Also, a comparison of the use of various fuels in copper refining furnaces was discussed 2 in a paper presented at the New York meeting of the Institute in February 1932. Prior to 1943 the cellroom was operated with twenty-five 720-lb. anodes and 26 cathodes per cell. Four cathodes, each weighing about 165 lb., were produced from an anode. In 1943 the weight of the anode was reduced to 460 lb., and two cathodes, each weighing about 190 lb., were produced from an anode. In 1949, a Billet Casting Wheel for the production of 3 in. diam phosphor deoxidized billets was built. A paper, presented at the New York Meeting of the Institute in February 1956, describes3 this plant and operation. In the electrolytic refinery, production is controlled by variation of the current density. In 1956, germanium rectifiers on a separate electrical circuit were provided for the starting sheet section so that current density could be maintained at any desired figure. Also in 1956, a program of modernization and enlargement of the Electrolytic Copper Refinery was started. This program, when completed, will raise the capacity of the Great Falls Electrolytic Copper Refinery approximately 33 pct, to 33 million lb. of cathodes per month. Furnace capacity for melting cathodes and anode scrap is ample to take care of the increased production from the electrolytic refinery. This fortunate condition came about primarily as the result of the three following changes: 1) The furnaces were lengthened 10 ft in 1922 when the fireboxes were found unnecessary for burning powdered coal. 2) Furnace life, and hence furnace capacity, was increased by the successful efforts of the Copper Refinery staff to develop a method for sanding furnace side walls and roof. 3) The natural gas being used has a very low sulfur content. As a result, it is possible to reduce time spent rabbling and poling and thus greatly increase tons per furnace charge. TANKHOUSE AND TANKS The Great Falls Electrolytic Refinery is 535 ft long by 252 ft wide. The cells are arranged in four crane bays in which are operated seven 10 ton Whiting Cranes. The old cells are in groups of ten, with circulation of electrolyte through five cells in cascade and with aisles between the groups of ten cells. The new cells are nested in groups of sixteen with no aisles, are all on one level, and have individual circulation to each cell. Present plans call for 1792 commercial cells and 128 stripper cells. To reduce confusion during the construction period, and to use the cranes, cars, and other equipment already on hand, the cells in the rebuilt section were designed to have approximately the same inside dimensions as the cells in the old part of the

Jan 1, 1962

By Irving Crosby

ELECTRICAL prospecting by potential methods has been applied to mining problems for some years and determinations of the depth to bed rock have been made, but so far as is known it has not been used previously in the solution of civil engineering problems, such as investigating the foundations of dams. During the past winter and spring the senior author has been engaged as consulting geologist in studying the site of a large darn on the upper Connecticut River and has had the satisfaction of introducing electrical prospecting to foundation problems. The valley across which the dam is to be built is underlaid by a deeply buried preglacial gorge which is filled with glacial deposits. An extensive drilling campaign was in progress, but the work was unusually slow and expensive on account of the number of boulders in the overburden. The necessity of speeding up the work was pressing and it was decided that much of the needed information could be obtained by geophysical methods. After investigating the various methods and conferring with the company engineers and with the consulting engineer, Albert Crane, a contract was made with the Schlumberger Electrical Prospecting Methods, and an observer with apparatus was sent to the dam site the first of April, 1928. The problem was to determine the depth to rock at various points in order to prepare a contour map of the bed-rock surface and outline the buried gorge in the vicinity of the dam site. Over one hundred determinations of depth have been made and the bed-rock topography, is now known in considerable detail. In addition, some information has been obtained about the nature of the overburden. The drilling has been continued; in fact, two additional drills have been put to work, and the electrical determinations have been checked at several points. At one of these the depth to rock given by the electrical work was 142 ft. and the drill found rock at 147 ft., an error of less than 4 per cent. The electrical work has also been checked by the geological study, and it has been found that when the electrical determinations are in agreement with the geological expectations they are probably reasonably accurate. When the electrical interpretation of the sub-surface topography is incon-

Jan 1, 1928

By V. R. Garfias

With the exception of the United States and Russia, none of the leading world powers have within their boundaries the oil supplies needed to meet present peace-time requirements, and even in regard to the United States it is admitted by competent observers that the known oil reserves within the country are inadequate to meet demands for more than a comparatively few years. It follows, therefore, that the transportation of petroleum—almost entirely by tank steamers—from foreign fields to the main consuming centers is one of the most important factors affecting the present and future development of the oil industry. The world-wide distribution of petroleum is affected by numerous factors of which international politics is not the least important. The assurance of an ample supply of petroleum—one of the most essential munitions of war—is of paramount importance particularly to those countries subjected to the rivalries of powerful neighbors. And paralleling the importance of the control of an ample supply is that of its safe transportation from the fields to the consuming centers. To illustrate: France is dependent almost entirely on foreign sources for its petroleum requirements estimated at close to 100,000 bbl. daily, and in order to control such a supply after the World War it acquired an interest in the Iraq oil fields. Lately it has undertaken the construction of a pipe line from these fields to the Mediterranean seaboard in Syria with the expectation that late in 1934 these fields will supply between 30 and 40 per cent of the country's requirements. It should be noted, however, that the availability of this supply is entirely dependent on the safe operation in the Mediterranean at all times of an adequate fleet of tank steamers. Thus, in order to transport 40,000 bbl. daily, it will be necessary for one 10,000-ton tanker to leave Tripoli, the Syrian port, say for Marseille, every other day throughout the year while to meet the entire present peace requirements of France from the Iraq fields, a fleet of some 30 such tankers must be kept in continuous operation between Tripoli and Marseille.

Jan 1, 1934

By James Hall

A geological map of a State involves very much, and its pre sentation to the public incurs grave responsibilities. It has been for a long time my earnest desire to bring out and place before the pub lic a geological map of New York which might be creditable to the State and worthy of a place among her scientific publications. We have done much for the advancement of geological science in this State—very much, and in many directions—but unfortunately, this feature, which should have been made the basis of all our work, has been too long neglected and delayed. For twenty-five years I have been laboring and looking forward to this consummation. I have recorded the field-work, systematic and desultory, upon such maps as were available for this use; and notwithstanding their imperfec tion, I have been able to transfer this recorded information to a more perfect base, which it is hoped will be completed during the early months of the next year. In 1883 I had combined, upon a small map of the State, the in formation which we possessed at that time, and communicated the same with my annual report to the Legislature. The report mas published in the regular course, but the special appropriation made for the map was vetoed by the Governor. Not discouraged by this untoward and unexpected circumstance, I continued my work, and made every effort to render the map more complete, preparatory to its communication with the next annual report. I brought together all the information within my reach, whether published or unpublished, reviewing and revising, as far as practicable, the work done by myself and assistants in southern and southeastern New York.

Jan 1, 1893

The cables brought the news last spring that the Institute had lost by death one of its most distinguished foreign members, Hjalmar Sjogren of Stockholm. For thirty-one years, Professor Sjogren had been one of our number. He was elected in 1891, joining the Institute at the time he was in the United States, in attendance at the Fifth International Geological Congress, which was held in Washington in the late summer of that year. Professor Sjogren was once more in America in 1906 and again in 1913, and on both of those visits his friends in New York had the welcome opportunity of extending courtesies to him. He was thus well known to a wide circle in our membership. His keen interest in the geology of iron ores brought him in touch with the many Americans who have studied them and who have been active in the important productive districts which he visited. Our Transactions contain (Vol. XXXVIII) one very important paper of seventy pages on the Geological Relations of the Scandinavian Iron Ores, which he contributed. Sten Anders Hjalmar Sjogren, to give his full baptismal name, was born June 13, 1856, and was the son of Anton Sjogren, a mining engineer, at the time in charge of the iron mines at Persberg, in the east and west iron-ore belt of central Sweden, about 160 miles west from Stockholm. The Persberg orebodies yielded magnetite and specular hematite from schists, with which limestones. were interstratified as well as the peculiar Swedish rocks called "halleflinte." The mines were also well known to collectors and students of minerals. While Hjalmar Sjogren was yet a lad, his father was advanced to the superintendency of a number of famous mining localities in this same district of Wermland. Paisberg, famous for its native lead, was one; and two others, Langban and Nordmarken, were among the most prolific sources of interesting minerals in all Sweden. In several localities, the pre-Cambrian limestones had obviously experienced the recrystallizing influences of intrusive igneous rocks and had been charged with the so-called "contact" minerals, which have found their way to the museums of the world. Anton Sjogren, the father, was a keen mineralogist and Hjalmar, the son, grew up in a favorable environment for receiving training and enthusiasms of the same sort. One is not surprised, therefore, to find Hjalmar Sjogren, in the long run, turning to mineralogy and geology as his final career.

Jan 1, 1923

By G. F. Butterworth

The metallographic structures most frequently encountered in rifle barrels, and which are illustrated by the accompanying photomicrographs, fall naturally into two groups, distinguished by the method used to, produce in the stock a physical condition having the requisite properties. The fist group consists of "rolled" barrels; that is, barrels subjected to hot working by rolling in or near the critical range. In the second group, the stock, which is smaller in diameter than the first, is upset to form the butt end and is then heat treated by giving it a quench and a draw. These barrels will be referred to as " heat-treated " barrels. The structure of the rolled barrels resembles closely that of the same steel after annealing. There is the same network of excess ferrite outlining the grain boundaries, but the grains themselves are composed of sorbite rather than pearlite. The grain size is closely related to the rolling temperature. The critical-point curves of this grade of steel, which is approximately 0.50 to 0.60 per cent. of carbon and 1.00 to 1.30 per cent, of manganese, show a single very pronounced point between 1300" and 1350" F. (704" and 732" C.). Barrels rolled within this temperature range give an exceedingly fine grain, shown in Fig. 1. In fact, the grains may be so fine that, at a low magnification, they may be confused with the heat-treated structure shown in Fig. 6. A magnification of 500 diameters, however, will always resolve a rolled barrel into the characteristic structure shown in Fig. 2. As the temperature is increased, the grains are found to be larger. If, on the other hand, the rolling temperature is below the critical range, the structure previous to rolling will not be obliterated, the only effect of rolling being to elongate the coarse sorbite grains in the direction of rolling, Fig. 3. This distortion is greatest at the muzzle. Heat-treated barrels are quenched in oil from above the critical range, which should give a martensitic structure, Fig. 4, but the presence of some troostite in the martensite is frequently noted when the quench has not been sufficiently drastic, Fig. 5. The structure brought about by the subsequent draw is not so striking, though quite as typical. It is sorbitic or sorbito-pearlitic, and under a low magnification appears almost homogeneous, as in the case of fine grains of pepper and salt well mixed together, Fig. 6. This structure is substantially the same for all

Jan 1, 1920

By Samuel M. Shallcross

The principal function of the Bell limestone mine, of the American Lime & Stone Co., at Bellefonte, Pa., is to supply raw material to the company's modern rotary kiln plant at Bellefonte. Because mining costs are naturally higher than many open quarries with more favorably lying strata, it cannot compete, except to a limited extent, in the markets for road material and fluxing stone. In the broad sense, mining does have an advantage over the average open quarry when the end products are designed for and controlled by process and final inspection for the exacting demands of the industrial and chemical markets. Approximately 80 per cent of the output of the Bell mine is sold in the industrial and chemical markets. And as higher standards are set each year for construction and agricultural work, the remainder of the mine output goes to these two classes. Mining produces more fines than open quarries, and these fines are difficult to market; on the other hand, owing to absence of contaminating clay and impure rock, a greater percentage of the output of a mine is marketable. Because of the great production of fines, rotary kilns for lime burning are necessary when the stone must be mined. In 1921 the American Lime & Stone Co. operated 19 quarries and 72 lime shaft kilns spread over an area of 40 miles between Bellefonte and Altoona, Pa. At that time the lime-production capacity of the 72 kilns amounted to approximately 700 tons per day. After 15 years the company operates three rotary kilns and six shaft kilns, with a combined output of approximately 500 tons of lime per day, concentrated in its single Bellefonte plant (Fig. 1). Its only stone-producing plants are now the limestone mine at Bellefonte and a construction-stone open quarry at Union Furnace, near Tyrone, Pennsylvania. Since the middle of 1922, the management of the American Lime R. Stone Co. has been under the direction and ownership of the Warner Company, of Philadelphia. To the Warner Company's experience, gained through successful operation of lime plants in eastern Pennsylvania for many years, and the successful solution of material-handling problems

Jan 1, 1937

By N. A. Gokcen

EQUILIBRIA in the reactions between gases and liquid metals have been the subject of many interesting investigations. The experimental realization of true equilibrium, however, is questionable in certain cases due to the lack of conclusive studies in reaction rates. It -will be shown here that a systematic interpretation of rate studies with the analysis of prevailing experimental conditions leads to valuable practical information. The reactions of particular interest are: H2(g) +S(inFe) - H2S(g) [1] H2(g) +O (inFe) =H2O(g) [21 2H2(g) + SiO2(s) = 2H2O(g) + - (inFe) [3] The usual and perhaps the most convenient method of investigation may be illustrated with reaction 1. A stream of gas mixture consisting of H2 + H2S is passed over or bubbled through the liquid metal at constant temperature. The ratio of H2S/H2 in the entrant mixture is fixed in each experimental run, and, therefore, the composition of melt varies until the establishment of equilibrium. The purpose of this paper is to derive a formula expressing the minimum time required for the establishment of equilibrium and to compare the calculated values from such a formula with the available data. Equations Reaction 1 is used for the purpose of illustrating the derivation. Let E represent the equilibrium and X the nonequilibrium sulphur in weight percent at any time t in minutes. For the sake of simplicity, it is first assumed that E > X although the results are of general applicability without restriction. It has been shown by Morris and Williams' that within a difference of 1 pct S or less, i.e., E-X5 1.00, the value of K'1 = Ph2s/Ph2.S% is very nearly constant. The maximum ratio of available Ph2s/Ph2 = H,S/H,, from which sulphur can be absorbed by metal, is equal to H2S/H2 in equilibrium with E (which equals H2S/H2 in the entrant gas), minus H,S/H, in equilibrium with X. Thus: Available H2S/H2 = EK'1 - XK'1 [4] Eq. 4 expresses that sulphur can be absorbed by metal from the H2S/H2 in the entrant gas until the gas leaving the metal assumes a value of H2S/H2 which is in equilibrium with the dissolved sulphur X at that time. H,S constitutes up to approximately 1 pct of the gas mixture. Its disassociation into H2 and SL is about 1 pct at 1600°C, hence, the H2S/H2 impinging on the surface of metal is very close to that in the entrant gas. The rate of flow of hydrogen entering the reaction chamber is kept constant experi-

Jan 1, 1954

Members whose deaths were reported from Mar. 5, 1919, to Apr. 5, 1920. Elected Died 1895 ANDERSON, ROBERT HAY 1920 1916 ATWATER, M. W 1919 1905 BARD, D. C 1920 1893 BECKER, GEORGE F 1919 1914 BIGELOW, BRAXTON 1917 1917 BLACK, HERBERT F 1919 1911 BOWLER, ROBERT P 1919 1902 BROWN, ARTHUR H 1919 1913 BURNHAM, WILLIAM 1918 1905 Carnegie, Andrew 1919 1900 CARPENTER ROLLA C 1919 1908 CONNER H. MCKEAN 1919 1883 COOK, ROBERT A 1919 1903 COOPER, JOHN 1919 1875 CROXTON, SAMUEL W 1919 1889 DICKMAN, R. N 1919 1893 DUFOURCQ, EDWARD L 1919 1917 FAY, CHARLES H 1918 1875 FOHR, FRANZ 1919 1879 FRICK, H. C 1919 1880 GAYLEY, JAMES 1920 1917 GARVIN, JOHN C 1920 1915 GIBBS, CHARLES H 1919 1917 GODBE, RALPH T - 1918 GREGORY, A. E 1919 1917 HAMILTON, A. McL 1918 1914 HEISE, HENRY C - 1913 HINCKLEY, E. R 1918 1884 JENNINGS, HENNEN 1920 1895 JOHNSON, J. E., JR 1919 1895 KANN, MEYER M 1919 1895 KAYSER, H. W. F 1919 1918 KENNEDY, DANIEL J 1903 KING, PAUL S 1919 1901 LANGTON, JOHN 1920

Jan 1, 1923

By J. D. Price, W. M. Bertholf

THE central washing plant of the Colorado Fuel & Iron Corp. was first operated in 1918 to furnish coal for two 60-oven batteries of Koppers design. Prior to that time the coke for the blast furnaces had been secured from a number of beehive operations, some with their own washeries. The original washery had four Elmore jigs, which did not do as well as had been expected. In 1923 the jigs were taken out and replaced by Deister Plat-O tables, with various changes in auxiliary equipment. In 1936 the throughput of the plant was considerably increased by the installation of vibrating filters for recovery and drying of fine coal, thereby reducing a large recirculating load of fine coal which passed through the screens of the Carpenter driers.

Jan 12, 1954

By H. I. Smith

CONTENTS [PAGE Problems of Mining and Processing Mineral Aggregates (TP 1649, by NATHAN C. ROCKWOOD, Min. Tech., Nov. 1943. Discussion by H. I. SMITH, IRVING WARNER and the author) t Mica in War (TP 1749, by RUSSELL G. WAYLAND, Min. Tech., July 1944. Discussion by H. S. SPENCE) 3 Three Roofing-granule Plants in Pennsylvania (TP 1787, by RICHARD M. FOOSE, Min. Tech., Jan. 1945. Discussion by H. I. SMITH)5 Methods of Prospecting and Mining Optical Calcite in Montana (TP 1896, by E. W. NEWMAN, Min. Tech., Nov. 1945. Discussion by W. C. STOLL and FRANK C. ARMSTRONG, and the Glass Sand and a Glass Industry in Puerto Rico (TP 1939, by HOWARD A. MEYERHOFF and J. EARL FRAZIER, Min. Tech., Nov. 1945. Discussion by A. M. SHORT, the author and PHILIP The "Bonanza" Mica Operation of Purdy Mica Mines, Limited, Mattawsn Township, Ontario (TP 2154, by HUGH S. SPENCE, Min. Tech., March 1947. Author's supplement and discussion by JOHN A. BAKER, E. J. LINTNER, and the author) 7 Process for Manufacture of Dead-burned Magnesite and Precipitated Calcium Carbonate from Dolomite (TP 2155, by ROBERT D. PIKE, Min. Tech., March 1947. Discussion by 0. C. RALSTON and the author) 9] Problems of Mining and Processing Mineral Aggregates H. I. SMITH*-Mr. Rockwood has presented a very interesting paper on problems of the mineral aggregate industry in meeting specification requirements, which apparently are ever decreasing in tolerance. May I call attention to a method of mineral separation that may be of value in separating the flat aggregate particles from the more angular ones and possibly the soft particles from the hard. The method is the old Pardee spiral coal separator, extensively used many years ago in the anthracite region for separating rock and bone from anthracite coal.1 The success of the process depends on the relative coefficient of friction of the aggregate particles to be separated rather than on their relative specific gravity. The flat and the soft particles normally will slide more slowly and stay on the inner spiral until they reach the delivery spout at the bottom whereas the round and the angular pieces will work to the outer edge and fall off into a spiral of larger diameter. The capacity of the separator is increased materially by having three inner spirals, with a separate feed for each, on which the particles travel more slowly, and one outer spiral from which the more rapidly traveling pieces slide to the bottom. IRVING WARNER*-I have long been convinced that much of the equipment and methods developed for mineral dressing might be advantageously employed in the mineral aggregates industry, and more particularly in the production of sand and gravel. The two industries are not well acquainted with each other or their problems. They have separate trade publications. The difficulty with the situation is that there are few large sand and gravel plants and few provided with technical services in their own organization or by retainer. This does not refer to engineering organizations but rather to improvement of plant technic in processing.

Jan 1, 1947

By Gardner F. Williams

Chemically, the diamond is composed of the element carbon in its pure crystallized state. The diamond crystallizes in the isometric system, and the most common forms are the octahedron and dodecahedron, while the (24-sided) tetrahexa-hedron is not uncommon. Cube diamonds with beveled edges representing the combination 8 0 8 and 8 0 2 are occasionally found in the Bultfontein and Premier (Wesselton) mines at Kimberley, South Africa. The diamonds from various mines have distinctive forms of crystallization, or variations of the same forms, so characteristic that those familiar with South African diamond-mines and their products can determine positively from which mine any given parcel of diamonds has been obtained. It is not always possible to determine the source of each individual diamond, for similar stones are occasionally found in digerent mines; but these are exceptions to the rule. There is a difference in the luster, shape or crystalline form of the diamonds from the various mines that gives each mine some distinctive characteristic. In one mine nearly all of the crystals are sharp-edged octahedrons, while in another, dodecahedrons with rounded faces predominate. One might give no end of peculiarities of the diamonds from the various mines; but it will suffice for the purposes of this paper to state the fact that such distinctive characteristics do occur. From this observation it may be concluded that the diamonds in the mines of the Eimberley district, which occupies a small area (see Fig. I), did not have a common origin. The diamond is the most impenetrable of all known substances, and will scratch any other stone, or the hardest steel. It is a very strong reflector of light, and refracts incident rays more than any other substance except crocoite.l

Jan 1, 1905

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 RICHARD W HUNT 1883

Jan 1, 1910

By C. E. Birchenall, R. H. Condit, M. J. Brabers

In the oxidation of pure iron above 700°C the overall rate is determined mainly by the rapid growth of wiistite, through which iron ions can diffuse rapidly.' Nickel added to the iron progressively decreases the stable range of composition of wustite.' When enough nickel is added to eliminate wiistite as a stable phase, the spinel is the fast growing phase. This investigation was undertaken to test the hypothesis that nickel substituting for iron in magnetite might decrease the rate of spinel growth by reducing the iron mobility. Nickel ferrite boules grown by the flame fusion process were purchased from the Linde Co. Chemical analysis gave an atomic ratio of iron to nickel of 2.88 and showed no other cations. They were cut into discs and ground to give flat, parallel faces. The experimental procedure employed was like that of Eisen and Birchenall in which the distribution of radioactivity diffused in from a vapor deposited surface layer was determined by counting the residual activity through a series of ground faces. The diffusivities were calculated in a manner consistent with the requirements discussed by Condit and BirchenallP The details will be given in connection with a more extensive spinel diffusion study now in progress. The results of the measurements are shown in the figure in comparison with earlier data on magnetite1 and zinc ferrite. The uncertainties arising from scatter in the activity vs distance relationship and uncertainties in the temperatures are shown by flags. Despite the scatter it is clear that substitution of a considerable part of the iron in magnetite by nickel, in this case about one third decreases the iron mobility substantially. sachs' determination of the distribution of iron and nickel in scales on iron-nickel alloys appears to show that nickel is less mobile than iron in the spinel layer. It is evident, therefore, that nickel plays several roles in reducing the oxidation rate of iron-nickel alloys. 1) It reduces progressively the stability range of wiistite. ' 2) It reduces progressively the stability range of the iron-nickel spinel phase in terms of the variation in cation to anion ratio.' 3) As shown in this investigation, it reduces the cation mobility in the spinel phase which is the faster growing phase in the absence of wiistite. The fe was obtained from the Oak Ridge National Laboratory. The research was supported by the Air Force Office of Scientific Research (ARDC) under contract number AF 18(600)-967.

Jan 1, 1961

By T. E. Evans, C. T. Baroch

ZrB2 was produced in batches of 4 to 6 Ib by interaction of ZrO2, B4C, B203, and carbon at around 2000°C in a simple graphite resistance furnace. Techniques of production are discussed and the final design of a suitable furnace is described in detail. Several other borides were made by the same technique and the process appears to have possibilities for commercial production. N seeking out new hard and refractory com- pounds, many researchers have turned to the investigation of the borides and excellent papers have been published on the properties of these compounds. Few papers, however, have appeared on the techniques and problems concerned with the production of these high temperature substances. This report describes progress made in developing a method for preparing zirconium diboride, ZrB2, on a pilot plant scale. The literature of the borides and other refractory hard metals recently has been reviewed, annotated, and classified so completely' that it is needless to attempt such an outline here. It is enough to say that three borides of zirconium have been reported: ZrB, ZrB2, and ZrB12.2 ZrB2 is the most stable of these and is especially stable in the presence of carbon up to and including its melting point of around 3000°C. Like most borides, it can be prepared in several ways. It can be prepared by synthesis of the elements, but these are expensive and difficult to produce in a high state of purity. Obviously, production directly from the oxides would have decided economic advantages. In electrolytic production such as that of calcium boride,:' the product is recovered as a sludge mixed with electrolyte; and separation of product from adhering electrolyte and regeneration of the electrolyte is an involved and difficult process. The work on borides was started on a small scale in 1948. Late in 1949, Naval Ordnance expressed a specific interest in ZrB2 and the project then centered on this compound. After the usual experimental work necessary in a new field, ZrB2 of good quality was produced by heating mixtures of B4C, ZrO2, B2O3, and carbon to a temperature of about 2000 °C in a resistance-type electric furnace. Over 100 lb was made for experimental use tests, and the method of production probably could be expanded into a commercial operation. A similar process has been described by Kieffer and coworkers.' The main chemical problems were the development of proper charges to insure complete reduction of the elements, determination of the proper temperature range at which these reductions took place, and adoption of techniques necessary to pre- vent inclusion of such impurities as carbon and nitrides. The mechanical problems consisted of developing a simple practical furnace that would attain the high temperatures required and permit use of a controlled atmosphere when necessary and determining of suitable refractories. Both problems were solved by designing a crucible resistance furnace. Crucible Resistance Electric Furnace Attempts were first made to produce ZrB2 in an electric arc furnace, but such a furnace would not provide the degree of carbon control required for producing clean graphite-free borides, so it was decided to try working in a crucible. Obviously, the furnace would have to be constructed of graphite, as the temperatures required are too high for other refractories or heating elements. Crucibles were made by hollowing out segments of graphite electrodes, which were fitted with a cover and clamped between two electrodes so that the current passing through the thin wall of the crucible would generate heat, using the principle of the Helberger crucible furnace."? Preliminary tests with this type of furnace were encouraging and led to the furnace design shown in Fig. 1. The essential components were a thin-walled graphite crucible resting on a graphite block, which formed the lower electrode assembly, and a top electrode assembly swung from a pipe column making contact with the top of the crucible. The space around the crucible was filled with graphite prepared from waste electrodes crushed to about ¼ in. This packing had excellent insulating properties, both electrically and thermally, and could be removed easily and quickly from around the crucible by means of an industrial vacuum cleaner. The largest resistor crucibles were machined from 8 in. electrode stock and were 26 in. long, with a side wall Yi in. thick and a 1 in. bottom. Temperatures were determined optically by sighting down a 1 in. hole drilled longitudinally through the top electrode and the crucible cover. Sealing this hole at the top was a water-cooled brass sight-glass assembly, shown in Fig. 2. An opening was provided for a light flow of helium to keep the sight opening clear of smoke, and a glass prism above the sight glass changed the line of sight to the horizontal for easier reading. More recently, the prism and optical pyrometer were replaced by a photoelectric recording pyrometer. At first the charges were placed directly in the resistor crucible but this meant that everything had to be withdrawn from the furnace every time the charge was emptied. Later, smaller crucibles were made up that could be placed inside the resistor

Jan 1, 1956

By James Herbert Bartlett

I desire, very briefly, to call the attention of the Institute to the iron trade of the Dominion of Canada. A wonderful development is now going on in Canada. The completion of the Canadian Pacific Railway, and the numerous extensions of the various railways all over the country, combined with the progress made in nearly every kind of manufacture, is drawing attention to the field offered in Canada for the profitable employment of capital, and specially to the opportunity there is for the manufacture of iron. In a paper presented to the Institute at the Halifax meeting,* the writer gave a review of the varions attempts to manufacture iron in Canada. The facts then presented were not such as to offer much encouragement to any one to embark in similar enterprises under the conditions then existing, but, happily, these conditions are now changed, and an early development may be anticipated. There are two reasons which make the present time an appropriate one to direct attention to the field offered for enterprise in this direction, the first being the very favorable reports of the experts who examined and reported on the exhibit of minerals at the Colonial and Indian exhibition, held in London, England, last year. The exhibits there of coal and iron attracted so much attention that at the request of the Iron and Steel Institute a paper on the " Ironmaking resources of our Colonies as illustrated by the Colonial and Indian Exhibition," was prepared and read at the last meeting of the Institute.? This report of 135 pages is very exhaustive, and the conclusion arrived at, so far as Canada is concerned, is, that she has in many parts of the country every natural facility for the manufacture of iron. The second and more important reason is the recent change in the Canadian customs tariff inaugurated in May last. The tariff is now generally two-thirds of the American tariff, in addition to which the Government, in order to encourage the manufacture of iron, grants a bounty upon pig-iron made in Canada out of Canadian ore.

Jan 1, 1888