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By Paul Billingsley

WHEN I was an undergraduate at the Columbia School of Mines, the mining curriculum was subdivided into two major branches's known respectively as the Metallurgical and the Geological Options, which diverged rather widely as the course progressed. When I duly elected the Geological Option, I believed, I am sure, that this divergence would continue throughout the years. The facts have proved otherwise. The mining industry is a closely knit entity in which the search for its raw materials, called mining geology, cannot be separated from the conversion of these raw materials into marketable form, called metallurgy. The mining geologist searches for materials which the metallurgist can utilize, and only such; and whenever an advance in metallurgy opens the gates for new materials, the geologist's problem is correspondingly modified. No better instance of this relationship can be given than that seen in the Salt Lake region in recent years. Our mineral industry here is of long standing. The three principal tributary districts, Bingham, Park City and Tintic, were discovered in the 1860's and have been vigorously and intelligently developed for many decades. Their production has made the Salt Lake valley one of the world's great smelting centers. The maintenance of this industry has for years depended upon the continual development of new orebodies to take the place of those being extracted. Intensive exploration in the old districts has been supplemented by prospecting in outlying districts of lesser prominence. . Many new orebodies have been discovered, such as those of the Daly West, Silver King, and Judge mines in Park City, the Utah Apex in Bingham, and the Sioux, Colorado Chief Consolidated and Tintic Standard in Tintic. New mines in other districts have been discovered also, but without affecting the dominance of the three major districts. In all cases discoveries, to be of value, had to be of ore amenable to treatment in the available metallurgical plants. This meant that, for the most part, zincy ores, both oxide and sulfide, must remain untouched, and also that ores high in iron and ores high in silica had a fictitious value, either high or low, set by the balance of these

Jan 1, 1928

By A. S. Malicsi, I. Iwasaki

The removal of hydrophobic coatings of flotation collectors from iron ores becomes of interest when a duplex flotation process is considered for upgrading, when a pelletizing process is considered for a concentrate floated with a fatty acid or a soap collector, or when a disposal of froth products from cationic silica flotation is of environmental concern. Ozone can oxidize organic compounds rapidly, thereby removing the hydrophobic coatings of flotation collectors. Ozone is widely used for treating and purifying drinking water, waste water treatment, and for chemicals processing (Murphy and Orr, 1975; Rice et al., 1980). Its uses in metallurgical operations, however, are very sparse (Allegrini et al., 1970; Chernobrov and Rozinoyer, 1975; Ishii et al., 1970; Iwasaki and Malicsi, 1985; Matsubara et al., 1978). Yet, its high reactivity and the absence of potentially hazardous byproducts become of interest in destroying flotation reagents adsorbed on mineral surfaces or remaining in mill water for recycle or for discharge. Duplex Flotation A duplex flotation process, as applied to oxidized iron ores, would involve a fatty acid flotation of iron minerals followed by an amine flotation of the siliceous gangue from the rougher iron concentrate. Such a process has been used in the Florida phosphate fields. Fatty acid coatings cannot be removed as readily with a simple acid or alkali treatment from iron oxide surfaces as from Florida phosphates. A combination of reagents, such as lime and quebracho, lime and alkali phosphate, or sulfuric acid and oxalic acid, has therefore been proposed. In a previous article (Iwasaki et al., 1967) , the use of activated carbon was found to be effective in removing fatty acid coatings both in the duplex flotation and the pelletizing processes. The use of ozone offers another approach to the removal of fatty acid coatings from iron oxide surfaces. To investigate the possible application of the duplex flotation process, a specularite ore from Michigan analyzing 36.5% iron was used. A 600-g (1.3-1b) sample was ground in a laboratory rod mill together with 250 g/t (0.5 lb per st) of sodium silicate to -150 µm (-100 mesh). This was transferred to a Fagergren laboratory flotation cell, and deslimed four times at 20 µm (quartz equivalent). The deslimed pulp was transferred to a laboratory conditioner, diluted to 40% solids, and conditioned with 250 g/t (0.5 lb per st) of soda ash and 250 g/t (0.5 lb per st) of oleic acid. The conditioned pulp was then transferred back to the Fagergren cell, floated until barren of froth, and the rougher froth product was returned to the cell and cleaned. The results are presented in Table 1. The cleaner concentrate at this point analyzed 45.3% Fe. The cleaner concentrate coated with fatty acid was transferred to a 2-L (0.53-gal) beaker. While the pulp was agitated with a glass T-stirrer, ozone was bubbled into the agitated pulp for 15 minutes at a rate of 10 mg/min (0.00035 oz per min) ozone (250 g/t or 0.5 lb per st 03 feed). It was observed that the pulp ceased to froth after about 10 minutes. The amine flotation of siliceous gangue from the ozonated pulp was carried out first by conditioning with a dextrin, a commonly used starch depressant for iron oxides. This was followed by flotation with a stage addition of an ether amine at increments of 100 g/t (0.2 lb per st). Three stages were required to float the siliceous gangue to near completion. The three froth products were combined and cleaned twice. When the cationic flotation Rougher, Cleaner 1 and Cleaner 2 cell products were combined, an iron concentrate analyzing 64.5% iron was obtained at an overall iron recovery of 72.8%. Pelletizing Fatty acid flotation concentrates have been pelletized successfully in northern Michigan mills. But at other locations, fatty acid coatings on iron flotation concentrates proved so undesirable in agglomeration that other methods of concentration had to be sought. For example, a sinter mix containing iron ore concentrates upgraded by fatty acid flotation resulted in decreased productivity. This occurred because the micropellets of particles with the hydrophobic coating are less tolerant of moisture. Thus, the bed permeability is lost (Beebe, 1965). The agglomeration of concentrates obtained by the fatty acid flotation alone, and the hydrophobic coatings destroyed by ozonation or by the duplex flotation process, is not expected to cause any difficulty since the surfaces of the concentrates would be hydrophilic. Removal of the fatty acid coating with activated carbon, indicated by the loss of floatability, was shown to restore the decrepitation temperature of wet balls during drying cycle (Iwasaki et al., 1967). Disposal of Cationic Silica Flotation Froths Recent demands of iron blast furnaces place the silica content of the magnetic taconite pellets at about 5%. Conventional process for magnetic taconite involving fine grinding and magnetic separation often produces magnetic concentrates analyzing in excess of 5% silica. This is due to the presence of the middling grains of siliceous gangue and magnetite. Cationic silica flotation of magnetic taconite concentrates (DeVaney, 1949) may be used to reduce the silica content. But the amine coating on siliceous gangue becomes of environmental concern when the flotation tailings are discarded in tailing ponds.

Jan 1, 1986

By Owen Rice

CHANGES in coke hardness affect the working of the blast furnace, for soft coke is an obstacle to proper furnace operation. Soft coke is due to a low hydrogen-oxygen ratio in the coal charged; increasing this ratio increases the hardness of the coke. The best means of determining the hardness of coke is the combined tumbler and ball-mill. Soft coke is a great hindrance to proper blast-furnace operation and changes in coke hardness affect the working of the furnace. The best method of determining the hardness of coke is by using a combination tumbler-ball-mill. Soft coke is due to a low hydrogen-oxygen ratio in the coal charged. An increase of this ratio improves the hardness of the resulting coke. WHAT IS GOOD COKE? It is not always appreciated that the correct answer may be such a reliable forecast to the physical condition of the blast furnace, and incidentally its entire operation, that among the ordinary variations in other raw materials and also in operating conditions, it assumes a position of primary significance. Inasmuch as coke forms two-thirds of the total bulk of material charged, this assertion will not seem exaggerated, and in the subsequent discussion its applicability will be presented. Coke is the ideal blast-furnace fuel because it is strong and hard enough to resist the crushing and grinding effects of the furnace burden, and its porosity allows the ready passage of gas upward through the charge, and rapid combustion before the tuyeres. Coke deprived of its strength and with a cell structure physically frail and chemically susceptible to solution by carbon dioxide, has its chief asset eliminated. When the melting zones are approached the fluid cinder trickling toward the hearth will envelope the small pieces of coke and form a sticky mass that will retard the free passage of gas. Blast pressure will then rise, driving

Jan 1, 1921

By L. A. Wright

Union Carbide Corp.'s Pine Creek mine in California is the largest known tungsten deposit in the West, and the producer of well over five million tons or ore to date. Located 21 miles northwest of Bishop on the eastern slope of the Sierra Nevadas, the mine is also a source of molybdenum and copper and it was the quest for the molybdenum which caused the mine management to undertake a pillar recovery program. GEOLOGY For a full discussion on the geology of the Bishop tungsten district and the Pine Creek mine, reference is made to Special Report 47, Calif. Div. of Mines. The deposit lies along a 3000 ft segment of the contact between quartz monzonite and the marble that flanks the west side of the north portion of the Pine Creek pendant. All the components of a typical contact metamorphic tungsten deposit are developed; these consist of tactite, light colored calc-silicate rock and quartzose rock.

Jan 5, 1964

By M. B. Bever, A. K. Jena

Equations for the heat effects of additions of mixtures of multicomponent phases to a solution have been derived in terms of the enthalpy interaction coefficients. By these equations and the measured composition dependence of the heat effects on addition of mixtures of Ag-Cd solid solutions and elemental gold to liquid tin-rich solutions, values of the enthalpy in-teraction coefficients in tin-rich solutions at 541°K have been obtained. Analysis of these results in terms of the regular solution theory and the quasichemical theory suggests that near the melting point of the solvent association in the solution becomes important. SEVERAL recent papers have discussed the nature of dilute solutions on the basis of measured enthalpy interaction coefficients. l-3 These coefficients contribute to the understanding of the constitution of solutions and can be used for the evaluation of thermo-dynamic data of multicomponent systems. Their experimental determination, however, is laborious. This communication reports values of the enthalpy interaction coefficients of silver, cadmium, and gold in liquid tin-rich solutions obtained from the measured heat effects of additions of mixtures of Ag-Cd solid solutions and elemental gold to liquid tin-rich solutions. These measurements were made in the course of the determination of the heats of formation of Ag-Cd solid solutions reported in a concurrent publication.4 THE HEAT EFFECT OF AN ADDITION TO A SOLVENT This analysis is concerned with the addition of a mixture of multicomponent phases from the temperature To to a solvent of known composition at temperature T. If Nmixture << Nsolvent, where N designates the gram-atoms involved, the heat effect per g-atom of mixture added can be expressed as (HT - HT )i = difference in heat contents of component element i in the mixture at T and To Q = heat effect on solution of the mixture at temperature T Also1 Q = S Xi [2] where ?Hi ,T,x = relative partial enthalpy per g-atom of i in solution at temperature T and composition of the solution x x = average of the atom fractions of the added material in solution before and after the addition The relative partial enthalpy ?Hi per g-atom of an element i in a dilute solution composed of a solvent 1 and the solutes j = 2, ... m is related to the interaction coefficients by the following equation5 ?Hi - ?Hi-?Hi,x1-1 + S n1ixj+ . . . +S...S...S nrixn2... Xnji...Xnmm+... [3] vhere Xj = atom fraction of solute j in the solution nri = the rth order enthalpy interaction coefficients, which can also be represented by the more general designation5 L(i)n2,n3...nm and nj may have any positive integral value or zero. For identification of various rth order interaction coefficients, nri is written as nn2i2,...nij,...nmm. Eqs. [1], [2], and [3] combine to give the following general equation for the heat effect on addition of a small quantity of a mixture to a large quantity of a dilute solution n = _?ga ?Ha,To + ? Xi(HT - HT o)i a. i + ?xi?Hi,X,i?1 + ??xnjixj + . . . + ???. . .?. . .?xinrix2n2. . . xnji. . . xnmm+ . . . [4] The first term on the right-hand side of this equation is the heat of decomposition at the addition temperature of the phases present in the mixture, the second term is the heat required to raise the temperature of

Jan 1, 1970

By Lauren A. Wright

General prosperity marked the industrial mineral industries of the U.S. and Canada in 1962. For most commodities, production and sales exceeded 1961 figures, and for several commodities, all-time production peaks were reached. Many millions of dollars were spent on exploration for and development of industrial mineral deposits, construction of new plant facilities, and expansion and modernization of existing plants. This generally satisfactory state is attributable mostly to a continuing high rate of building and heavy construction. However, for large segments of the industrial mineral field, 1962 was a year of increasingly severe competition and of problems, either existing or potential, of overproduction and overcapacity. Such problems are of particular concern to the asbestos, cement, potash and sulfur industries. As in years past, the trend continued toward larger-scale operations to permit lower production costs per unit of material mined, toward more stringent quality controls and toward marketing methods that provide greater efficiency and customer convenience.

Jan 2, 1963

By T. A. Boyden

The Free World uranium market is now characterized by production nearly twice that of consumption result- ing in a rapid build-up of uranium inventories. Low- cost production from high-grade deposits in Australia and Western Canada will gradually add another 10 to 15 million pounds U308 annually into Free World production throughout the 1980&apos;s. This latter material cannot be absorbed in further inventory build-up and can only displace higher cost production. The result is a restructuring of the Free World producer industry. United States and Eastern Canadian producers have the higher cost production which gradually will be displaced from the market during this decade. As United States production declines, United States utilities must increase their reliance on foreign supplies in order to meet their needs. This paper reviews the elements that will cause the restructuring of the Free World producer industry and the expected response of the United States utility industry to that developing situation.

Jan 1, 1982

By K. L. Clark, Nicholas Kowall

MAXIMUM furnace efficiency and close control of final steel composition demand that the steel melter be able to follow closely the variations in the carbon content of the bath. For many years, the fracture test has been used by melters for estimating carbon, because it requires only a very short time to pour a sample into a chill mold, cool it in water, break it with a sledge hammer, and observe the fracture. After long experience gained from the observation of such fractures, most melters are able to estimate the carbon content of steel with amazing accuracy, particularly in the lower carbon ranges. Notwithstanding the utility of the fracture test, there has been widespread interest in other methods for rapid carbon determination to supplement it and to ensure against possible errors in human judgment. Several methods, based upon measurement of magnetic properties as functions of carbon content, have been described in the literature1-6 and have been found to give reasonably reliable results in plant practice when scrap composition is known and controlled. A difficulty encountered in the use of analyzers of the magnetic type is that alloying elements do change the relationship between carbon content and magnetic properties and it becomes necessary to establish calibration curves for all the expected combinations of alloy residuals that are not oxidized in the bath. The work reported here is of an investigation of a method that is independent of alloying elements normally present in constructional steels, being based upon the relatively well-known fact that in plain carbon and low-alloy steels martensitic hardness is a function of carbon content alone. WORK OF OTHER INVESTIGATORS In 1938, Burns, Moore and Archer published a curve7 that showed that the hardness of martensite is a function of carbon from 0.10 to 0.50 per cent and is independent of grain size or alloy content, at least within the range found in constructional S.A.E. compositions. Some of the deeper hardening types investigated, however, contained carbon to a maximum of only 0.20 per cent. Using this principle, Kern8 developed a method of rapid carbon determination for S.A.E. 43xx steels. His procedure consisted of chill-casting a test bar that was large enough to give a surface that could be prepared for Brinell indentations. The test piece was quenched immediately after solidification was complete and hardness readings were taken, so that the carbon content could be read from an experimentally determined curve giving the relationship between as-quenched hardness and carbon. EXPERIMENTAL WORK Although Kern&apos;s work had been done with a relatively deep-hardening steel, it

Jan 1, 1944

By G. J. Cardwell

The rock and mineral analyst will be called upon to determine both the major and minor constituents in materials as varied as rocks, soil, sediments, concentrates and various liquids. These analyses will have interactions requiring extraction, matrix modification, and background correction. Analytical methodologies include classical gravimetric methods, such as fire assay, emission spectroscopy, X-ray fluorescence, atomic absorption, inductively coupled plasma, and neutron activation. With these capabilities the analyst can be called on to determine three-fourths of the elements in the periodic table. How can the earth scientist pick the method best suited for his particular sample?

Jan 1, 1984

By George H. Eldridge

The existence of phosphate of lime within the State of Florida has been known for over a decade; but until the spring of 1887, the extent and value of its deposit.;, possibly with one exception, were unsuspected. In that year Col. T. S. Moorehead, induced by a statement made by Mr. J. F. Le Baron, examined the gravels of the Peace river, recognized the importance of the deposits, acquired such tracts as were regarded as desirable, and established the pebble-phosphate industry, making his first shipment in May, 1888, to the Scott Manufacturing Company, of Atlanta, Ga. The establishment of the pebble-phosphate industry upon Peace river was followed, a year later, by the discovery in Marion county of an entirely different class of phosphate, now commonly known as hard-rock phosphate. This discovery was made early in June, 1889, by Mr. Albertus Voght, in a well which he was sinking upon his place near the site of the present town of Donnellon, about 20 miles southwest of Ocala. To it, more than to any other cause, is due the rapid and remarkable development of the present great industry of the State. It was, however, Mr. John F. Dunn, of Ocala, who turned to advantage the accidental discovery of Mr. Voght. After acquiring a knowledge as to the chemical composition and value of the material, Mr. Dunn and hid associates purchased several thousand acres of land and organized the Dunnellon Phosphate Company for active operations. From Dunnellon as a center, prospecting rapidly extended in all directions, until at the present day important mines have been opened over a well-defined tract more than 200 miles long and about 6 miles wide. This tract lies par-

Jan 1, 1893

By T. S. Lundy, R. E. Pawel

Effects of short-circuiting paths on observed diffusion behavior in real crystalline systems are considered. It is concluded that experimentally measured diffusion coefficients may vary widely from values associated with true lattice diffusion to those appropriate for short-circuiting paths alone depending upon the conditions of the experiment and the sensitivity and completeness of the data. IN 1961 Harrison1 classified experimentally observed diffusion behavior in systems involving both lattice and dislocation-enhanced atomic transport into three categories. His types A and C were limiting cases where the measured diffusion coefficients using the usual serial sectioning techniques were representative of lattice diffusion (with only slight effects of dislocations) and dislocation-network diffusion (with only slight effects from lattice diffusion), respectively. In both cases A and C for a sectioning experiment in which the diffusion couple has the semi-infinite geometry and unidirectional diffusion takes place from a plane source located at the origin of the coordinate system, he pointed out that Gaussian penetration behavior should be observed. For case A the lattice coefficient should be slightly enhanced by dislocation contributions, and the model of Hart2 can be used to predict the amount of this enhancement. For case C the observed coefficient should be that for the dislocation network and have little or nothing to do with lattice diffusion. Hart&apos;s model in its general form is still applicable, but the apparent diffusion coefficient for this case is virtually independent of dislocation density. Harrison&apos;s case B is that for which non-negligible contributions exist for transport by both mechanisms and "the concentration distribution does not approximate to any simple form." With the possible exception of very low temperatures where diffusion distances approach atomic dimensions, any real diffusion specimen will in general show non-Gaussian behavior provided the data are complete enough to uncover it. Thus, a "complete" set of data for any real system cannot be expected to be totally amenable to treatment by a simple mathematical model which does not take into account the relative distribution of transport by the various modes or submodes. For a particular sensitivity of specimen analysis and at a given temperature of annealing if the concentration profile could be observed as a function of time, "the behavior will initially be type C, and will develop into type B. and ultimately type A".1 Thus, it appears that the type of diffusion behavior which is experimentally observed in a given system depends very much upon the particular experimental conditions and the particular tools available to obtain the data. Interpreted in this fashion, Harrison&apos;s classification refers not to the diffusion behavior as a whole but to the relative sensitivity of the method of examination and completeness of the data. In the present paper we will: 1) assume that the measured penetration behavior follows the same general classification as that proposed by Harrison; 2) give, for diffusion in tungsten, examples of the range of diffusion coefficients that it is possible to obtain in a single experiment; and 3) speculate that some arguments which consider the possibility of short-circuiting effects being responsible for "anomalous" diffusion in several bcc metals may have been discarded prematurely.3 Both monocrystalline and polycrystalline tungsten were used in this work. The former was obtained as triple-pass, electron-beam zone-refined 6.0-mm-diam rod from Materials Research Corp.. Orange-burg. N.Y. The latter was swaged, high-purity bar stock which was annealed for 2 hr at 2200°C and 10-9 torr to yield an average grain diameter of about 25 /i. The tracer Nb95 was received in oxalate solution from the Isotopes Division, Oak Ridge National Laboratory. Experimental procedures of specimen preparation, isothermal diffusion annealing, serial sectioning by anodizing-and-stripping, and y counting of the individual sections to determine the tracer penetration profile after a given diffusion anneal have been described elsewhere.4 However, it should be noted that the anodizing-stripping sectioning technique has the particular advantage for this research of permitting sectioning to be accomplished over a wide range of

Jan 1, 1970

By Paul Billingsley

When I was an undergraduate at the Columbia School of Mines, the mining curriculum was subdivided into two major branches&apos;s known respectively as the Metallurgical and the Geological Options, which diverged rather widely as the course progressed. When I duly elected the Geological Option, I believed, I am sure, that this divergence would continue throughout the years. The facts have proved otherwise. The mining industry is a closely knit entity in which the search for its raw matcrials, called mining geology, cannot be separated from the conversion of these raw materials into marketable form, called metallurgy. The mining geologist searches for materials which the metallurgist can utilize, and only such; and whenever an advance in metallurgy opens the gates for new matcrials, the geologist&apos;s problem is correspondingly modified. No better instance of this relationship can be given than that seen in the Salt Lake region in recent years. Our mineral industry here is of long standing. The three principal tributary districts, Bingham, Park City and Tintic, were discovered in the 1860&apos;s and have been vigorously and intelligently developed for many decades. Their production has made the Salt Lake valley one of the world&apos;s great smelting centers. The maintenance of this industry has for years depended upon the continual development of new orebodies to take the place of those being extracted. Intensive exploration in the old districts has been supplemented by prospecting in outlying districts of lesser prominence. Many new orebodies have been discovered, such as those of the Daly West, Silver King, and Judge mines in Park City, the Utah Apex in Bingham, and the Sioux, Colorado Chief Consolidated and Tintic Standard in Tintic. New mines in other districts have been discovered also, but without affecting the dominánce of the three major districts. In all cases discoveries, to be of value, had to be of ore amenable to treatment in the available metallurgical plants. This meant that, for the most part, zincy ores, both oxide and sulfide, must remain untouched, and also that ores high in iron and ores high in silica had a fictitious value, either high or low, set by the balance of these

Jan 1, 1928

* Kennecott Copper Corp. gets Charles R. Cox as president on Jan. 1. Mr. Cox is resigning his position as president of Carnegie-Illinois to take the new post with Kennecott, left vacant by the death of Mr. Stannard in September. •The ECA signed a contract in December to advance X3,600,000 to Newmont Mining Corp. to aid development of lead and zinc mines in French Morocco. The funds are to be repaid in lead and zinc for the United States&apos; stockpile over a period of seven years. The mines are owned by the Societe des Mines de Zellidja, with which organization Newmont is associated. • Under the direction of John M. Brooks, Jr., general manager, the Matahambra mine in Cuba, will probably produce sufficient tonnage to make 4 million lb of copper per month during 1950. The grade is presently running between 7 and 10 pet. •S. H. Ash reports that the fatality rate per million-man-hr for the anthracite industry for 1949, through November, is 0.78. This is 15 pct better than that achieved during 1948, which was the lowest fatal injury rate in coal mining history. The first full year on record without a major disaster was recorded in 1949 (p. 34). •The Atomic Energy Commission has authorized the production of 200 lb of uranium metal for use under AEC license in non-Commission research projects. •A national survey of projected 1950 purchases of new machine tools, machine tool accessories, materials handling equipment, etc., just completed by the American Society of Tool Engineers reveals that, of the companies reporting, 80 pct state that they plan to buy either more equipment or the same amount as in 1948. • Armour Research Foundation is conducting investigations for the use of clay and shale deposits to make lightweight aggregates. The material is heated until it expands and forms material suitable for mixing with cement which it is hoped will be lighter, stronger, have better insulating qualities and will lower the cost of concrete. •In the first six months of 1949 the bituminous coal miners&apos; average hourly earnings were $1.94 -as compared with X1.392_ national average for all manufacturing. Average annual earnings of full-time employees in the bituminous coal mines in 1948 were $3387 as compared with $2809 for all industry. •LaSalle Business Bulletin reports: "year ends on a rising trend in industry and trade ... nearly record-breaking demand from almost all sources keeps business high... most indicators but little below postwar peak... forces keeping activity high arestill powerful--changes in general business conditions likely to be slow and moderate." •Office of Internal Trade of the Commerce Department requests that technical data significant to the national security which is to be sent outside of the United States be submitted to it for an official opinion on the desirability of transmitting such information. This voluntary compliance program is part of our national security control. • Blast furnace slag reduced to 12 to 16 mesh is being used for sanding track at the Mont Coal mines of Armco. The slag replaces silica sand which caused silicosis. It has proved so effective and cheap that tests are being made to use the slag for rock dusting.

Jan 1, 1950

By N. A. Gokcen, S. Fujishiro

THE pressures of Mn(g) in equilibrium with Mn7C3 and graphite have been measured by McCabe and Hudson&apos; and Butler, McCabe, and paxton2 by means of graphite, zirconia, and Ta-Mo Knudsen cells. The details of corrections in their measurements were somewhat different from those of the authors;3&apos;4 hence, further independent results at higher temperatures seemed to be warranted. The stoichiom-etry of Mn7C3 in equilibrium with graphite and its stability up to the vicinity of 1373 °K have been satisfactorily established by Kuo and persson5 (See also Hansen and Anderko).&apos; The method of investigation has been described elsewhere in detail.3&apos;4 The carbide was prepared in the manner described by McCabe and Hudson. In order to avoid possible reactions with refractory oxides, only graphite cells were used for the effusion experiments. The authors&apos; results are the runs M-1, M-2 and M-3 listed in Table I, together with those of McCabe and co-workers. The heat capacity, c;, of Mn7C3 is not known; therefore McCable et al. plotted their data as log P vs 1/T and the results were only expressed first&apos; as, and later2 as logP=- -14220+6.06 without further thermodynamic calculations. However, it is possible to estimate closely the necessary heat capacity as follows: When H; - &98 of CrC, or MnO, is plotted vs x, corresponding to various compounds, with temperature as the parameter, it is seen that the relationship is represented by a line of very small curvature. This relationship is also followed by other compounds which do not exhibit solid state phase transformations. In view of the fact that chromium and manganese have the atomic numbers of 24 and 25 respectively, it is reasonable to assume that H; - H;ae vs x for MnC, follows the same type of lines as those for CrC, for which adequate data are available.7 Similar correlations appear to be valid for oxides of two neighboring metals for which reliable data are available. The procedure is thus to move the lines for CrC, vertically (parallel to the axis of HT - H298) until they coincide with the points for MnC1/3, the only carbide of manganese whose H; - HO298 has been

Jan 1, 1963

By G. F. Loughlin

Nearly 55 years have elapsed since the U. S. Geological Survey was organized. During this period the mineral industries have grown from infancy or early childhood to well developed maturity, and some mining industries appear to be declining. Decline in mining is even more conspicuous in certain districts, or even states, than in any mining industry as a whole, and discoveries or developments of important new districts have been very few in recent years. Our reserves of most metals and nonmetals are adequate for many years of normal production, subject to changes in rate of exploitation that may be caused by foreign competition and by changes in technology and market conditions; but the declining production of many districts and the scarcity of important new discoveries to compensate for them is cause for some apprehension. It is likely that future production will depend to a considerable extent on deep exploration and on the thorough examination of places in and adjoining existing districts where significant outcrops are lacking and only apparently insignificant geologic features offer encouraging clues—more so than on the discovery of entirely new districts. Even the possible discovery of new districts, which have escaped the intensive search by the nontechnical prospector, must be dependent on geologic information. There is therefore no need for argument as to the value of geology to the mining industry; and the need of continuing to advance the science. The U. S. Geological Survey&apos;s past contributions to mining geology, as expressed in its official reports and other publications, are recognized by Ransome in his historical review of mining geology in the Lindgren volume.&apos; These contributions have helped to form the basis of modern mining geology, which has grown rapidly in the last 25 years. This growth has witnessed the organization and maintenance of geologic staffs by mining companies in several districts, and their detailed work, together with the fact that nearly all of the larger mining districts have

Jan 1, 1935

By W. J. Schuster

*Original Pages Missing From Book HANNA COAL CO., Division of Pittsburgh Consolidation Coal Co., operates three large under- ground mines in eastern Ohio. The section of Pitts- burgh No. 8 coal seam in which these mines are located varies in thickness from 52 to 64 in. It is immediately overlain by a stratum of shaly material 12 to 15 in. thick locally known as draw slate, which is structurally very weak and which disintegrates rapidly upon exposure to atmosphere. Immediately above the draw slate as it is normally found is a band of extremely high ash material 6 to 12 in. thick known as roof coal or rooster coal, and above this is a stratum of conglomerate material varying from 4 to 10 ft in depth. Overlying the conglomerate is&apos; a relatively thick stratum of limestone, the first stable material above the Pittsburgh coal seam in eastern Ohio. With the method of full-seam mining that has been adopted, draw slate is shot down, loaded with the coal, and removed in the preparation plants. The roof coal then becomes the permanent roof. The major problem in mining the No. 8 seam in eastern Ohio is control of the roof. Since the strata above the draw slate contains no material with a structure firm enough to provide self-support, the roof begins to sag in a relatively short time after the coal and draw slate have been removed. The problem thus becomes one of getting temporary safety posts under this roof as quickly as possible to prevent a break or separation from occurring either in the roof coal or in the conglomerate above it.

Jan 5, 1954

By Joseph E. Pogue

The prices of crude petroleum and its derivatives have shown an upward trend from 1915 to 1920, and a downward trend from 19&apos;20 to 1923, see Table 1. Over the former period, oil prices were dominated by the rapidly increasing demands and inflation incident to the war and its aftermath, while over the latter period oil prices were influenced at the outset by deflation and then by the conditions of overproduction that have characterized the past three years. he purpose of this paper is to analyze the broader features of the more recent price movements in the petroleum industry and to relate these features to basic economic conditions in the industry. Index Numbers of Oil Prices The analysis and comparison of price movements may be facilitated by converting actual prices into relative prices, or index numbers, with 1913 taken as a base of 100. In this way, the various price groups are expressed as percentages of the 1913 prices and may thus be readily compared with one another or with the average prices of other commodities similarly expressed. Table 1 gives the index numbers representing the average prices of crude petroleum, gasoline, kerosene, fuel oil, lubricating oils, and all commodities. The last named is the index of all commodities as published by the U. S. Bureau of Labor Statistics and is widely accepted as the official measure of the general price level. The index numbers of oil prices were calculated by the writer from weekly quotations published in trade journals. Fig. 1 shows in graphic form the trend of oil prices by months over the period 1920-23. It may be observed that the prices of crude oil and its derivatives move in rough conformity with one another; tend to follow

Jan 1, 1924

By H. M. Davis, T. S. Jones

A methodfor accelerating the reduction of a metal oxide by carbon monoxide is to incorporate in the reduction system a nonreducible oxide which has a strong affinity for carbon dioxide and will remove it from the product gases. The effectiveness of this method was investigated by veduction experiments on specially prepared powder mixtures of SrO-ZnO ("active&apos;.) and SrCO3-ZnO (reference). Measurements at 750o and 677°C showed that the rate of reduction of ZnO by CO was as much as an order of magnitude greater in the presence of SrO. Under the experimental conditions at least as much CO2 as generated by veduction was absorbed when SrO was present. Enlzancernent of the veduction rate by SvO resulted from modification of&apos; gaseous djfitsion processes. THE specific question posed in this investigation was whether the reduction reaction CO + ZnO - Zn(g) + COa [1] could be accelerated by incorporating strontium oxide into the oxide charge undergoing reduction. Provided the strontium oxide was active enough, it could remove carbon dioxide from the product gases of ( 11 and form strontium carbonate, thus modifying Reaction [ 1] to CO + ZnO + SrO = Zn(g) + SrCO3 [ 2] This study of the comparative rates of Reactions [ I] and [2] can be considered as a particular case of a general scheme for increasing the rates of reduction of metal oxides by carbon monoxide. The limits of applicability of this scheme are indicated in the simple thermodynamic analysis presented in the appendix. This analysis primarily dictated the choice of the system, CO-ZnO-SrO, employed in this investigation. In addition, it was thought that a study of this scheme by use of the CO-ZnO-SrO reaction system would be of special interest in view of indications in the literature1-3 that the gaseous reduction of zinc oxide is prone to rate control by diffusion in the gas phase. The distinction should be pointed out between this and other efforts to increase the rates of reduction reactions through the use of addition agents. Additions of a wide range of chemicals have been tried with de- grees of apparent success varying from slightly negative to highly positive. The reasons for making additions have included the use of salts to produce effects akin to catalysis,4, 5 the alteration of the microstruc-tural details of the reduction process (including solid-state diffusion),6-8 and the conversion of an en-dothermic reaction into one that is exothermic or autogenous.9-12 The means used to attempt alteration of the enthalpy change has commonly been to incorporate lime into the charge, so that heat is generated by reaction with either of the reaction products, carbon dioxide or water. The use of lime in this way makes endeavors such as that of Edstrom and Wiberg similar to the present one. Furthermore, the basic principle behind the present work has previously been set forth.13 However, a detailed investigation of the type of reaction described in this work does not appear to have been conducted. EXPERIMENTAL PROCEDURE From both conceptual and physical standpoints, Reaction [2] is to be considered as the sum of two reactions:

Jan 1, 1968

By M. O. Holowaty, C. M. Squarcy

Bituminous coal furnaces give way to coke, and by 1880, the American iron and steel industry was growing at a tremendous rate. In the twentieth century, the number of operating blast furnaces was cut in half while pig iron capacity more than doubled. Bituminous coal furnaces Attempts to relieve the shortage of charcoal by the use of bituminous coal in American furnaces began quite early. Use of bituminous coal in the blast furnace was restricted to areas lacking anthracite deposits but rich in deposits of bituminous coaL The largest concentration of bituminous coal furnaces was in Western Pennsylvania, West Virginia and Western New York state. Other areas included Kentucky and southern portions of the states of Indiana and Illinois. The first trials were made in Pennsylvania around 1780. Gradually several more furnaces began charging coal with their burdens as a partial substitution for charcoal. These so called cheaters were numerous, especially in Western Pennsylvania, which around 1810 began to expand its ironmaking capacity to catch up with the Lehigh Valley and the Schuylkill According to the existing references, complete bituminous coal burdens began to be used in this area only around 1840 when the ironmakers hastily adopted the hot blast apparatus introduced from England. The majority of these furnaces were built, however, after 1844 when an extensive experimental program, carried out at the Shenango Steam and Water Hot Blast Charcoal, Coke and Raw-Coal Furnace produced favorable results, with coal containing up to 35 pct volatile matter. The furnace was located near the Shenango River on the Lackawannok Run, five miles northwest of Mercer, Pennsylvania. It was built, owned, and operated by David Hogeland of Mercer. The first furnace was built in 1836 or 1837 as a charcoal furnace. Soon, however,

Jan 1, 1961

By Joseph Hodgson

Introduction SINCE about 70 per cent. of the total cost of mining is due to underground work which is out of sight, it is essential that expenditures should be made here to the best advantage. A great many mistakes have been made which were expensive, but perhaps these have not even been detected by mine owners. In the future these may be minimized to some extent, especially if there is cooperative effort on the part of each employee. I have been interested in this subject for some years and have tried to deduce principles and methods. These have proved highly advantageous and may also be of help to others. Some corporations, like the United States Steel, and the Cleveland-Cliffs Iron Co., have done a great deal in this field by having stated meetings of their organizations, with the view to interchanging ideas among their men and educating them along the lines of concerted effort. Since no man knows all about the various branches of mining, it is advisable that frequent meetings of the operating department be held for the interchange of ideas and that all members of the organization have an opportunity to express themselves on the various subjects. It has often been found that in discussions between heads of departments, foremen and bosses, many valuable suggestions may be obtained which promote the best interests of the company. The method regarded as the most conducive to cooperative effort, and pursued by the organization, is to analyze and develope the different phases of various mining subjects at regular meetings.

Jan 5, 1916