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By T. J. Woodside

A. E. LEE*—One question of the flue leading to the tube coolers. What gas velocity is maintained to prevent settling of the finely divided fume ? T. J. WOODSIDE (author's reply)— 30 fps. Of course some fume settles out, but is immediately carried away by the screw conveyors. H. R. BIANCO —How effective are the soot blowers ? Do you have to use any hand lancing? T. J. WOODSIDE Only one point, which is right at the top of the economizer and which the soot blowers do not reach, we occasionally hand lance. But everywhere else the soot blowers have been very effective and no hand lancing has been done. L. V. DAVIDSON*—Do you have considerable variation in the lead content of the fume collected if the lead is higher, and is there greater tendency for the fume to stick on the boiler tubes ? T. J. WOODSIDE—There is very little variation in the lead content. From 5 to 7 pct is the widest range variation we have had and we have noticed no difference in the behavior of the fume. C. R. KUZELL—Mr. Woodside has been quite generous with data pertaining to metal and fuel economics. I think he stated that the coal consumption of the furnace was 21/10 21/10 for a pound of zinc recovered. I take it that that is the gross coal input to the furnace. I wonder what the net fuel consumption in terms of coal might be after crediting the fuel equivalent of the waste heat steam recovered? T. J. WOODSIDE—The fuel value of the waste heat steam is approximately 42 pct of the heat input to the furnace. A very large part of the heat, of course, goes out in jacket water—44 pct. A. D. TERRELL*—I would like to know how much lead is in the deleaded material. T. J. WOODSIDE—It is a little less than 2 pct now.

Jan 1, 1950

By W. H. Triplett

Silver-lead-zinc replacement deposits occur in limestones of the anticlinal Caja range at Providencia, near Avalos, Zacatecas, Mexico. The description deals with intrusives, outcrops, preferred horizons, changes from bedding to fracture, control in depth, and variations in abundance and ratios of minerals throughout a vertical range of 500 m. THE purpose of this paper is to record a few field observations and accumulated office data concerning outcrops, relation of ore occurrences to intrusive and host rock, and mineral zoning. Reasons for some of the phenomena are not clear to the author so the facts are given with the hope that other investigators may be able to furnish the explanations. The Avalos unit of the Compania Minera de Penoles, S. A., operates the Alicante, Bonanza, Providencia, Albarradon, San Eligio, Nazareno, Leona, Salaverna, and Santiago mines situated between Avalos railroad station and Concepcion del Oro on the Coahuila and Zacatecas railroad in the State of Zacatecas, Mexico. Some of these mines are within Penoles property while others are on mining claims leased from the Compania Nazareno y Catasillas, S. A., Mazapil Copper Co., and the American Smelting and Refining Co. The main office and camp are at Providencia, about 170 km southwest of Monterrey, N. L., so the silver-lead-zinc mines of the district are usually referred to as the Providencia mines. The Aranzazu, Catarroyo, and Cabrestante copper-gold mines are situated a few kilometers to the southeast on the same mountain range near Con- cepcion del Oro, the name by which the camp is known. It is operated by the Mazapil Copper Co. The main theme in the following pages is a description of the silver-lead-zinc ore occurrences of the district. Rock Formations Sedimentary Rocks: Many competent geologists have contributed generously to an ample fund of information concerning the sedimentary columns of northern Mexico. Among them are Carlos Burck-hardt, E. Bose, L. B. Kellum, and R. W. Imlay. Carlos Burckhardt, who covered a number of extensive areas in many parts of the Mexican Republic, devoted years to mapping the geology of the Caja, Zuloaga, and Santa Rosa mountain ranges around Mazapil, Concepcion del Oro, and San Pedro de Ocampo, Zacatecas. He did most of the original mapping which has been used as a basis and amplified by others. C. E. Burbridge and, more recently, John

Jan 1, 1953

By W. H. Triplett

Silver-lead-zinc replacement deposits occur in limestones of the anticlinal Caja range at Providencia, near Avalos, Zacatecas, Mexico. The description deals with intrusives, outcrops, preferred horizons, changes from bedding to fracture, control in depth, and variations in abundance and ratios of minerals throughout a vertical range of 500 m. THE purpose of this paper is to record a few field observations and accumulated office data concerning outcrops, relation of ore occurrences to intrusive and host rock, and mineral zoning. Reasons for some of the phenomena are not clear to the author so the facts are given with the hope that other investigators may be able to furnish the explanations. The Avalos unit of the Compania Minera de Penoles, S. A., operates the Alicante, Bonanza, Providencia, Albarradon, San Eligio, Nazareno, Leona, Salaverna, and Santiago mines situated between Avalos railroad station and Concepcion del Oro on the Coahuila and Zacatecas railroad in the State of Zacatecas, Mexico. Some of these mines are within Penoles property while others are on mining claims leased from the Compania Nazareno y Catasillas, S. A., Mazapil Copper Co., and the American Smelting and Refining Co. The main office and camp are at Providencia, about 170 km southwest of Monterrey, N. L., so the silver-lead-zinc mines of the district are usually referred to as the Providencia mines. The Aranzazu, Catarroyo, and Cabrestante copper-gold mines are situated a few kilometers to the southeast on the same mountain range near Con- cepcion del Oro, the name by which the camp is known. It is operated by the Mazapil Copper Co. The main theme in the following pages is a description of the silver-lead-zinc ore occurrences of the district. Rock Formations Sedimentary Rocks: Many competent geologists have contributed generously to an ample fund of information concerning the sedimentary columns of northern Mexico. Among them are Carlos Burck-hardt, E. Bose, L. B. Kellum, and R. W. Imlay. Carlos Burckhardt, who covered a number of extensive areas in many parts of the Mexican Republic, devoted years to mapping the geology of the Caja, Zuloaga, and Santa Rosa mountain ranges around Mazapil, Concepcion del Oro, and San Pedro de Ocampo, Zacatecas. He did most of the original mapping which has been used as a basis and amplified by others. C. E. Burbridge and, more recently, John

Jan 1, 1953

By H. M. Chance M

The following tables have been compiled from the annual reports of the Inspectors of Mines, to determine the percentages of fatal and non-fatal casualties from roof-falls and explosions of fire-damp. As we cannot assume that every accident has teen recorded by the inspectors ; as many casualties terminating fatally after the lapse of a considerable period, are inevitably recorded as " non-fatal;" and as clerical errors may have crept into the compilation,* the figures of these tables cannot be considered absolutely correct, but the summary is sufficiently reliable to show the features I wish to differentiate. Under the heading " Miscellaneous" are included all accidents not directly attributable to explosions of fire-damp, roof-falls or fails of coal. Prominent among the numerous causes included under this head are premature or delayed explosion of blasts, accidental explosion of powder or cartridges, accidents from mine cam, falls in shafts, machine accidents, sliding of loose coal in pitching breasts, suffoca tion by choke-damp, etc., comprising in all 48 per cent. of the total number of casualties.

Jan 1, 1882

By Richard P. Rothwell

Though coal has been mined in this country for more than a century, no systematic effort was ever successfully made to ascertain the total amount produced. The production of the Cumberland Basin, Md., and the shipments from the anthracite fields of Pennsylvania, have been placed upon record, thanks to the intelligence and foresight of Mr. C. Slack in the former case, and to the late Mr. B. Bannan in the latter. For some of the years between 1822 and 1842, the production of the Richmond Basin was reported by Mr. R. C. Taylor, but since that date till the author undertook this work it was impossible to obtain any statement of the production of this field. A few of the newer fields, such as that of Mt. Diablo, Cal., have been fully reported, and a few of the newer States have also had this service performed by some intelligent private individuals; but no statistics of coal production have ever been collected either by the State or General Government, if we except the returns for the years 1869—70 of the census report. During the year 1875, by great exertions, I succeeded in obtaining, and July 3d, 1875, gave in the Engineering and Mining Journal what, " though not an accurate statement of our coal production," was " by far the most full and reliable that had ever been published." Though that report showed the production of bituminous coal to be 23,630,094 gross tons, or about six million tons more than had ever before been reported, it was in reality two and a half million tons below the actual output. The more full returns I obtained for 1875 gave many figures for 1874

By H. L. Talbot, A. J. Hall, R. S. Young

A method for the chemical differentiation of oxidized cobalt from sulphide cobalt in complex mine and concentrator products is of considerable interest to a number of mining companies throughout the world. At Rhokana Corporation, in Northern Rhodesia, for instance, cobalt is found chiefly in the sulphide form, as carrollite, but a cobalt oxide mineral also occurs irregularly underground, and relatively small quantities in the mill feed from time to time are difficult to detect visually at the concentrator. The oxide cobalt is not amenable to the sulphide flotation process used at Rhokana and nearly all of it passes into the tailing. The occasional period when high tailing losses occur with no appreciable change in the cobalt content of the mill feed has naturally been disturbing to the concentrator staff, who had no means of determining whether an influx of cobalt oxide ore or laxity on the part of the mill flotation operators as responsible for these results. A procedure for determining oxidized copper minerals, based on their solubility in dilute sulphuric acid saturated with SO2, has been used for many years in the copper industry. In the presence of cuprite the procedure fails, but otherwise it gives results quite satisfactory for control pur- poses. Empirical methods for determining oxidized forms of zinc and lead have been proposed, but they are generally unsatisfactory except in isolated cases of a very simple ore. No published procedure for determining oxidized forms of cobalt or siinilar elements has come to the authors'notice. Experimental Procedure There are obviously two alternatives in attacking a problem of this nature. One is to employ a solvent for oxide cobalt that will not dissolve cobalt sulphide. The other is to find a substance capable of oxidizing the cobalt sulphide to sulphate, which of course is water-soluble and can then be leached from the water-insoluble oxide cobalt. A representative sample of Rhokana cobalt oxide ore was secured, ground to minus 200-mesh, and carefully rolled to furnish a standard sample for this work. The analysis of this material gave the following percentages: Co, 0.55; Cu, 1.64; Fe, 2.98; S, 0.08; SiO2, 41.42; Al2o3, 11.20; CaO, 13.82; MgO, 3.80. As a source of cobalt sulphide a similar large sample of carrollite was prepared, analyzing Co, 23.36 per cent; Cu, 27.32; and S, 31.13. This sample of course was not pure carrollite, but was the best obtainable in quantities sufficient for a standard intended for considerable work. It was a pure sulphide sample, microscopic examination showing only carrollite, a little bornite, and gangue, with no visible sign of oxidized ore present. A wide variety of reagents as used in an effort to selectively dissolve oxide cobalt or to oxidize sulphide cobalt to

Jan 1, 1949

By Frank Woolley, John F. Elliott

The high-temperatzrre solulion calorimeter has been modified and an extension dynamic analysis of i/s transient behavior has provided an improved basis for interpretation of the experimental data. The partial molar heats of mixing, Him, of aluminum, copper, and silicon in the corresponding binary liquid-iron alloys haz,e been measured directly at 1600°C. The resulls in kcal per g-alom are: THE high-temperature1,2 solution calorimeter was planned and designed to obtain directly the partial molar heat of solution of solute elements in a variety of liquid metals that might serve as solvents. Results obtained in the temperature range of 1000° to 1200°C were described in the two earlier publications. However, a long-term goal in the program has been to obtain measurements at 1600°C of the heats of solution of elements in liquid iron. Hence, subsequent to the work last reported,2 and based on the experience of the first two studies, the calorimeter system has been modified and operated at 1600°C to obtain measurements on the Fe-Si, Fe-A1, and Fe-Cu systems. This paper reports the results of the work. THE MODIFIED SYSTEM It was clear from the earlier results that the most precise measurements can be obtained with the high-temperature solution calorimeter when the solution time is less than approximately 30 sec. This can be achieved only when the bath temperature, Tb, is above the melting (liquidus) temperature of the solute material being dropped. A second point of importance is that the refractories used earlier liberated considerable water so that, although the oxygen potential of the atmosphere in the system was satisfactory for work with nickel and copper, it was too high for work with iron, silicon, and so forth. Third, for work at 1550" to 1650°C, an improved temperature-sensing unit is needed. The modified calorimeter in its latest form is shown schematically in Fig. 1. The refractory brick and the Kanthal-Super heating elements which formed the furnace for heating the solute addition have been replaced by a smaller resistance-heated tube furnace which is insulated with bubble-grain alumina. A more elaborate gas purification system was installed to maintain a satisfactorily low oxygen potential in the atmosphere of the calorinieter chamber and of the solute addition furnace. As was the case in the earlier work, at the beginning of a run the calorimeter chamber is evacuated and then filled with purified argon so that a total pressure slightly in excess of 1 atm is maintained during the run. When either of the furnaces within the enclosure attains a red heat, 6 pct H2 is added to the atmosphere. Throughout the run, gas from the calorimeter is circulated through a de-oxidation system at the rate of approximately 5 standard liters per min; the changeover time for the gas within the calorimeter enclosure is approximately 1 hr. The essential stages of the deoxidation system are: a copper furnace at 600°C, a drying tube of anhydrite, and a titanium furnace at 800°C. The oxygen potential of the gas stream in the purification system can be monitored at several points by a stabilized zirconia oxygen cell. This cell is invaluable in detecting the development of leaks in the container vessel and the gas circulating system. The installation of the solute-addition furnace allowed either of two types of temperature-sensing units to be mounted on a water-cooled probe. The first was a small optical device using a silicon diode that was

Jan 1, 1968

By J. A. Richardson

J. A. RICHARDSON[t]-Mr. Stuckey's account of the geology of the kaolins of North Carolina suggests that they exhibit some features similar to those of the Malay Peninsula. About one half of British Malaya (some 26,000 square miles) is occupied at the surface by igneous rocks, of which granite and its associated derivatives constitute fully 90 pct. The average granite is a biotic variety. It is predominantly potassic but carries, in addition, notable amounts of soda and lime so that albite and albiteoligoclase are generally common constituents of the rock. The minor derivatives from granite "magma" likewise include potassic and sodi-potassic members. Decomposition of the granitic rocks has led to the formation of kaolin in many localities, but, in general, the deposits are rather small and, at present, none is exploited commercially. True primary or residual kaolins (as defined by Stuckey; p. 48 Vol. 173, p. 2 TP 2219) have been developed from feldspar veins, pegmatites and from other granitic differentiates which cut through the larger masses of granite; they are usually small and narrow. Kaolin has been derived from aplite, quartz porphyry, quartz micro-porphyry, felsites and microgranites belonging to a complex known as the Chegar Perah-Pulai intrusion in northwest Pahang and southwest Kelantan. The bulk of the component rocks has been more or less strongly sheared. Kaolin-like end products have been formed from both sheared and nonsheared varieties. Kaolin has been formed also by the complete breakdown of trondjemite flanking the northwestern and western margins of the complex Bukit Ranjut syenite intrusion in northwest Pahang. These trondjemites range in composition from essentially quartz-free albiteplagioclasites to quartz-free microcline rocks; they are, in effect, the syenitic homologues of white sodic and potassic granite-aplites. The granites in Malaya have generally undergone more or less severe surficial weathering leading to the production of a spongy and rather cellular or a soft "mealy" material (sandy clay) down to depths of about 100 ft; in places the granite is strongly decomposed down to 150 ft. There has occurred, therefore, widespread partial kaolinization, but, in general, no extensive deposits of good quality kaolin seem to have been formed by these processes of decay. Frequently, the katamorphic processes of desilicification have advanced beyond the production of kaolin towards the formation of lateritic end products. The more important Malayan kaoiins seem to be confined to the western alluvial plains, particularly in areas either where granite crops out at surface, or where it forms the bedrock of the alluvium. There are numerous excellent examples around Gopeng and elsewhere in the Kinta Valley of Perak. Such kaolins belong to Stuckey's groups of secondary deposits, and, like them, these also may be bedded. Field observations have established the existence of what for want of a better name is referred to by the Malayan Geological Survey as "granite wash." It is believed that granite, undergoing extensive deeply penetrative and probably rather rapid destruction under humid tropical weathering (temperature around 90°F; rainfall about 100 in. per annum; high humidity) "flowed," was moved by "creep" and, in addition, probably slumped in large waterlogged masses of sandy clay from topographic salients onto the adjacent flats. Either during this period of transmigration or later when the sludged granite detritus, after having more or less come to rest, was attacked by flowing water, differential sorting and erosion took place with the result that the resorted debris was moved and later deposited as bedded alluvium. In this way, banded "granite wash" was produced comprising alternating bands of clayey sand (resorted granite sludge) and white

Jan 1, 1947

The following is an incomplete list of members and guests who called at Institute headquarters during the period Oct. 10, 1919, to Nov. 10,1919. Carl A. Allen, Salt Lake City, Utah. W. G. Mitchell, Montreal, Canada. M. M. Altmayer, Paris. Henry S. Munroe, Litchfield, Conn. A. E. Bellis, Major Ord., Springfield J. S. Negru, New York, N. Y. Armory, Springfield, Mass. Edmund Newton, New York, N. Y. R. S. Botsford, New York, N. Y. A. W. Newberry, Cleveland, Ohio. Henry S. Burnholz, Monterrey, Mexico. C. C. O'Harra, Rapid City, S. D. D. E. A. Charlton, New York, N. Y. Fred S. Porter, Philadelphia, Pa. C. C. Colburn, Denver, Colo. Donald A. Powell, Columbus, Ohio. C. V. Corless, Coniston, Ontario. Thomas T. Read, Washington, D. C. I. N. Daily, Seattle, Wash., W. L. Remick, Chrome, N. J. E. V. Daveler, Butte, Mont: Hallet R. Robbins, San Francisco, Calif. John Davis, Fairbanks, Alaska.' Milnor Roberts, University Station, E. W. Engelmann, Salt Lake City, Utah. Seattle, Wash. M. E. Erdofy, New York N. Y. Thos. S. Roberts, Lakehurst Proving W. F. Ferrier, Toronto, Canada. Grounds, N. J. H. A. Fisher, Pittsburgh, Pa. George B. Rodgers, Dobbs Ferry, N. Y. Walter Fitch, Sr., Eureka, Utah. John C. Rogers, Copper Cliff, Ontario. C. D. Grier, New York, N. Y. Joseph L. Rosenmiller, Bethlehem, Pa. A. Hibbert, London. . C. J. Saville, Portland, New South Wales. John E. Hodge, Minneapolis, Minn. W. A. Scheuch, New Jersey. W. E. Hopper, Newark, N. J. S. B. Shutts, Lynchburg, Va. M. R. Hull, McGill, Nev. E. W. Smith, U. S. Army. A. W. Ibbett, Trinidad, B. W. I. S. J. Speak, London. A. O. Ihlseng, Joplin, Mo. John. B. Stewart, Santiago de Cuba, Sherwin F. Kelly, Lawrence, Kans. Cuba. R. G. Knickerbocker, Logansport, Ind. S. A. Taylor, Pittsburgh, Pa. .M. H. Kuryla, Eureka Colo. Karl Thomas,' New York, N. Y. F. G. Lasier, Detroit, Mich. F. L. Torres, Eureka, Nev. David Lasuer, Elizabeth, N. J. Henry Traphagen, Toledo, .Ohio: H. H. Lauer, Allentown, Pa. W. D. Van Doren, Ottawa, Canada. J. Whitney Lewis, Care First Nat'l Bank, J. A. Vernon, Newport, R. I. Tulsa Okla James Wilding, San Francisco, Calif. James W. Love, Knoxville, Tenn. D. J. Williams, Butte, Mont. Dorsey A. Lyon, Washington, D. C. Harry J. Wolf, New York, N. Y. M. E. Martiner, Boston, Mass.. Dwight E. Woodbridge, Duluth, Minn. Benj. L. Miller, Bethlehem, Pa. Percy E. Wrighn, Seattle, Wash. W. G. Miller, Toronto, Canada. F. Yamada, Tokyo, Japan.

Jan 12, 1919

By N. A. Zeigler

GRaphitization phenomena occurring in solid cast iron have principally been studied from the angle of the reactions taking place during annealing of white castings in the manufacturing of malleable iron. The selected bibliography at the end of this paper presents the high spots of the published information in this field. Graph-itization of gray iron upon reheating has received much less attention, primarily because only on rare occasions is this material subjected to any kind of industrial heat-treating. Moreovcr, articles made from gray iron are seldom used commercially at temperatures when any graphitization can take place. When used in such conditions, it is assumed that the articles can be replaced at frequent intervals, which can be afforded because of the low cost of gray iron. However, there is at least one commercial process in which articles made from gray iron, during their manufacturing processing, are subjectcd to rather high temperatures; that is, manufacturing of cast-iron enamelware, which is glazed at about 1600° to 1700°F. (870' to 930°C.) From practical experience, it has been found that one of the convenient and economical compositions of gray iron suitable for enameling is, in round figures, as follows: Si, 2.50 per cent; Mn, 0.35; S, 0.07; P, 0.80; T.C., 3.35; C.C., 0.70. Since this iron usually is cast into thin-walled sections, the percentage of com- bined carbon in it is relatively high. Upon heating in the enameling furnaces, this combined carbon graphitizes, which causes permanent dimensional changes of the articles. Obviously, from practical considerations, it is desirable to maintain these dimensional changes as constant as possible. In the course of experimentation with this iron, two series of experimental heats were prepared in which the manganese to sulphur ratio of the standard cupola metal was offset by ladle additions of: (I) progressively larger amounts of sulphur, and (2) progressively larger amounts of manganese. Each one of these ladle charges was cast into experimental plates 8 by 4 in. and about 5/16 in. thick. All told, 13 ladle charges were thus treated. All of them are listed in Table I, together with their chemical analyses. It may be noted that the manganese to sulphur ratio in these samples ranges between 1.2 and 30.2. Every one of these compositions was subjected to thermal allalysis, using an automatic, self-recording differential dila-tometer. The specimens used in this instrument are 50 mm. long and 4 mm. in diameter. During the dilatometer cycle they are kept under a vacuum of about 3 microns. Each one of them was subjected to a thermal cycle by heating it to I830°F. (1000°C.) in 3 hr. and cooling to room temperaturc in 5 hr. Figs. I, 2 and 3 present three automatically recorded dilatometer curves for irons: Serial No. I (normal composition), Serial No. 6 (high sulphur), and Serial No. 13 (high manganese). All three of these figures are

Jan 1, 1945

By Oliver Bowles

ROCK is no doubt the most abundant of all material things because the planet on which we live is made of it. All animal and vegetable organisms and the multitude of natural and manufactured products that occupy a comparatively insignificant film on the outer surface of the planet are derived from rock. Processes of Nature acting for untold centuries have transformed rock into soil, making possible the development of vegetable and annual life; and rocks have supplied the numerous raw materials, metallic and nonmetallic, wherewith the innumerable appurtenances of a complex civilization have been fabricated. As time goes on we live with increasing speed and with enlarged desires. Time and space are shortened by man's ingenuity, and products for human use must be manufactured with greater and greater celerity. It was inevitable that Nature's slow processes of rock alteration should fail to keep pace with human demands and that the variety of natural products should fall far short of the requirements of an industrial age. Man therefore supplemented these processes by attacking rock in its native bed amid using it to supply needs not otherwise satisfied.

Jan 1, 1934

By G. Van Esbroeck, M. Van Weyenbergh

The copper mines of the Katanga region in the Belgian Congo lie along the same mineralized belt as those of Northern Rhodesia. There are two distinct types of deposits in that belt, the dolomitic and the quartzitic. In the dolomitic type the metallic minerals are found in a dolomitic limestone country rock. Through oxidation and enrichment, large deposits of high-grade oxidized copper ores were formed, some of which are being worked by the Union Minière du Haut Katanga. Such deposits are all in Katanga. The quartzitic deposits are found in Katanga and Northern Rhodesia. Here the primary mineralization occurred in sandstones and quartzites, in horizons stratigraphically lower than the dolomites. These rocks are not favorable to secondary enrichment and the oxidized zone is poorer than the sulphide zone, which alone contains the ore. There are also in Katanga a few ore-bearing veins. One of them is being worked in the Prince Leopold mine at Kipushi. Prince Leopold Mine The Kipushi ore body fills a fault vein and invades the wall rocks more or less extensively by metasomatic replacement. The vein strikes north-northeast and south-southwest and dips to the west. The variable dip averages 60' to a depth of 300 ft., and more uniformly 80' below 400 ft. In the upper section the average width is 200 ft. and below the width is about 150 ft. The length of the ore body is 2300 feet. The eastern side of the vein—the footwall—is dolomitic and contains irregular masses of ore sometimes extending 100 ft. or more from the main

Jan 1, 1940

By M. Van Weyenbergh, G. Van Esbroeck

The copper mines of the Katanga region in the Belgian Congo lie along the same mineralized belt as those of Northern Rhodesia. There are two distinct types of deposits in that belt, the dolomitic and the quartzitic. In the dolomitic type the metallic minerals are found in a dolomitic limestone country rock. Through oxidation and enrichment, large deposits of high-grade oxidized copper ores were formed, some of which are being worked by the Union Minière du Haut Katanga. Such deposits are all in Katanga. The quartzitic deposits are found in Katanga and Northern Rhodesia. Here the primary mineralization occurred in sandstones and quartzites, in horizons stratigraphically lower than the dolomites. These rocks are not favorable to secondary enrichment and the oxidized zone is poorer than the sulphide zone, which alone contains the ore. There are also in Katanga a few ore-bearing veins. One of them is being worked in the Prince Leopold mine at Kipushi. Prince Leopold Mine The Kipushi ore body fills a fault vein and invades the wall rocks more or less extensively by metasomatic replacement. The vein strikes north-northeast and south-southwest and dips to the west. The variable dip averages 60' to a depth of 300 ft., and more uniformly 80' below 400 ft. In the upper section the average width is 200 ft. and below the width is about 150 ft. The length of the ore body is 2300 feet. The eastern side of the vein—the footwall—is dolomitic and contains irregular masses of ore sometimes extending 100 ft. or more from the main

Jan 1, 1940

By M. J. Pool, P. J. Spencer, J. R. Guadagno

THE present work was carried out as part of a general program to study the magnitude and concentration dependence of exothermic heats of solution of various metals in liquid tin. Thermodynamic data for the Te-Sn system are very limited, particularly for dilute alloys. Indeed, apart from the prior heat of solution determinations of Pool,1 the only other published values are those of McAteer and seltz2 who carried out electromotive force measurements on solid alloys of compositions from 75 to 95 at. pct Te at temperatures between 543° and 668° K, of Colin and Dro-wart3 who made mass-spectrometric studies of the vapor in equilibrium with solid SnTe, and of Robinson and Bever4 who determined the heat of formation of SnTe by solution calorimetry. The present work thus provides further thermodynamic information for this system, specifically in a temperature range where the solubility of tellurium is very limited. The liquid metal solution calorimeter used in this investigation has been described previously.' No further discussion of its design or operation will therefore be given here. For each series of measurements a tin bath consisting of approximately 70 g of 99.99 pct pure Sn was carefully weighed out and inserted in the calorimeter which was maintained at the desired temperature to within ± 1/4°c. Tellurium, of 99.999 pct purity, was supplied by Atomergic Chemetals Co., a division of Gallard-Schlesinger Chemical Manufacturing Corp. Approximately 0.0006 to 0.001 g-atom specimens of tellurium were used for each experimental run and these were added to the calorimeter from a temperature of 273" K. Heat of solution values were calculated by analysis of a strip-chart recorder plot of the heat effect accompanying the solution of each sample in the tin bath. The heat capacity of the latter was determined at regular intervals during a series of tellurium drops by using pure tin or tungsten calibration samples, the heat contents of which were obtained from the standard compilation of Hultgren et al5 The composition of the bath was calculated after each drop from a knowledge of the weights of tin and tellurium added. Values of the heat of solution of tellurium at 725" and 775° K are listed in Table I together with the corresponding tellurium contents of the alloys. The data are also plotted as a function of tellurium concentration in Fig. 1, which includes the equivalent data obtained by pool' at 750° K. It can be seen that the heat of solution remains

Jan 1, 1969

By B. J. Bayles, J. A. Ford, M. J. Salkind

Unidirecltonally sulidijied AL-A13Ni was found to exliibit excellent microstructural stability to 508°C. Above this temperature the transverse micvostructure coarsened in a manner analogous to "Ostwald Ripening", but the A13Ni whiskers did not spheroidize or foreshorlen. The coarsened whiskers reinforced the matrix as effectirely as the finer whiskevs and no reduction in room-temperature tensile strength mas noled after exposure for 90 hr at 96 pel 0-1 the absollite melling temperature of the eulectic. The slability was auribucted to the presence of low-index (and presurrlably lor-energy) cvystallographic interjaces between phases. The driving force for microstructural coursening was presumed to be the reduction of interfacial energy between the phases. Finer micvoslructures were found to coarsen more rapidly than those which weve imitally coarser. FIBER-reinforced metals have been shown to exhibit good short-time tensile properties at elevated temperatures.1-4 However, many elevated-temperature applications require long-time property retention which dictates the necessity for microstructural stability. Two types of instability are common to fiber composities. The first, chemical instability, is due to chemical reaction between the matrix and the relnforcing phase. Petrasek and weeton5 have shown that chemical reaction between tungsten wire and several copper alloy matrices resulted in degradation of the reinforcing phase and reduction in strength of the composite materials. Kreider and Leverant4 have noted similar behavior for boron-reinforced aluminum above 400°C. The second type of instability arises in systems in which the phases are essentially chemically stable with respect to each other and is characterized by spheroidization and/or agglomeration of the reinforcing phase. parratt6 has reported this type of degradation to occur relatively rapidly at moderate temperatures for nickel and cobalt alloys containing whiskers of silicon nitride, aluminum oxide, and silicon carbide and has identified it as "physicochemical" instability. Although both types of instability are the result of the differences in the chemical potential between the fibrous phase and the matrix, they may be differentiated by the fact that the second type, "physicochemi-call' instability, results in little or no net change in the composition or amount of each phase present. It does, however, result in a morphological change which profoundly affects the strengthening mechanism. Chemical interaction. on the other hand, results in a change in the composition and amount of one or more of the phases present, or the appearance of a new phase. In the latter case, the appearance of the mi-crostructure, that of a fibrous phase aligned in a matrix, may remain essentially unchanged, but the chemical degradation of the fiber results in markedly reduced composite strength. This investigation was initiated in an attempt to evaluate the microstructural and related mechanical property changes of a whisker-reinforced eutectic composite after elevated-temperature exposure. The composite system chosen for this study was the uni-directionally solidified A1-A13Ni eutectic which Lemkey. Hertzberg, and Ford7,8 demonstrated to behave as a whisker-reinforced composite. The microstructure of the unidirectionally solidified material consists of aligned needles of A13Ni in a matrix of aluminum. EXPERIMENTAL PROCEDURE Eutectic ingots having a nominal composition of 6.2 wt pct Ni were produced by melting 99.99+ pct A1 and 99.99 pct Ni in recrystallized alumina crucibles in an argon atmosphere. The analyses of the starting materials are listed in Table I. These master heats were cut up? melted by induction heating, and unidirectionally solidified vertically in 1/2 -in.-ID. 6-in.-long graphite crucibles, in a dynamic argon atmosphere. Therma1 gradients in the liquid were determined by measuring the temperature in the melt as a function of apparatus travel distance, as discussed by Kraft and Albright.9 The rate of solidification was assumed to be equal to the uniform rate at which the crucible assembly was withdrawn from the furnace. Ingots representative of nominal growth rates of 2, 5, and 11 cm per hr were produced and the solidification parameters are summarized in Table 11. Ingots used for met allographic analysis were pre-

Jan 1, 1968

By T. M. Chance

THE first bituminous coal cleaning-plant to use the sand-flotation process1 was placed in operation on Oct. 1, 1925, at the tipple of the East Broad Top Railroad & Coal Co., at Mt. Union, Pa. The general principles governing the design of plants of this type and typical operating results of anthracite sand-flotation units have been previously outlined.2 I will, therefore, confine myself to a description of this particular plant and to some of the elements of design it incorporates. THE ORIGINAL MT. UNION TIPPLE The plant was installed to transfer coal from steel narrow-gage cars of 60,000 and 70,000 lbs. capacity to standard-gage equipment. The coal was hauled some 30 miles from the East Broad Top field. This coal, mined by the Rockhill Coal & Iron Co. and other operators, is a low-volatile slow-coking coal with- ash of high-fusion point. It is normally a high-grade coal that does not contain an excessive amount of free impurities, but it requires careful handling to secure a fair domestic yield, and, naturally, the need for narrow-gage transshipment increases the difficulty of the problem. The narrow-gage cars were discharged into an 8-car track hopper equipped with two feeders passing the coal to two 42-in. apron intake conveyors. Twin units were installed throughout in this original plant, two lump-and-egg shaking screens, two lump picking-tables, two egg picking-tables and two stoker conveyors. The stoker coal was loaded without cleaning. The loading tracks and booms were in duplicate and with the layout as originally installed either unit could be run independently, each unit shipping a different class of coal or both units making the same product.

Jan 2, 1926

THE following statement is contained in an article entitled "Mortgaging the Future." by Walter C. Teagle, president of the Standard Oil Co. of New Jer-sey, appearing in the current issue of the Lamp, the official organ of the Standard Oil Co.: "During the last eight months the domestic daily production. of crude oil has risen 300,000 bbl.. which means that no less a volume than 2,500,000 bbl. now are coming to market each day. . . . Every twenty-four hours 250,000 bbl. more than the consumer required are being added to our surplus oil storage. The temporary advantage of cheap petroleum products and the availability of fuel .oil, for a widespread use as a substitute for coal are not being weighed against the time when scarcity may follow on the heels of plenty and the public of tomor-row may have to pay for today's excesses. The over-production of crude and its consequences constitute a problem of national import which far outweighs the temporary advantages either to a part of the industry or to sections of the public.

Jan 8, 1927

By C. Edwin Nighman

THE following is a description of the methods used in rescuing men and extinguishing the underground fire at the Pennsylvania mine, Butte, Mont. This fire, which cost the lives of 21 men, began about 9 p.m., Feb. 14, 1916, at or near a ventilating fan on the 1,200 air-shaft station. This shaft at that time was downcast, while the main hoisting shaft was upcast. Owing to the proximity of the fire to the air shaft, the air in the latter soon became heated, and as the fan on the level was not running¬the power having been cut off shortly after the outbreak' of the fire-the aim' shaft became upcast to the 300 level. At this point a blanket of cold air from the surface caused the smoke and gases to he drawn in on that level and carried down again through the workings to the 1,200. A short time after the discovery of the fire, water was turned down the air shaft through a series of pipes around the collar of the shaft, which caused the smoke to recede, below the 300, so that within 2 hr. it was possible to search that level for the missing men. From the above it will be apparent why the air shaft was upcast instead of downcast as under normal conditions, and why men were suffocated at considerable distances from the seat of the fire. The smoke and gases that came up the main hoisting shaft did not diffuse through the workings to any extent. There are doors on all levels in the connections to the main hoisting and air shafts, but-in the confusion and running around many of these doors were left open, and this undoubtedly caused the smoke and gases to spread more rapidly than they would otherwise have done. It was necessary for most of the men on the various levels to pass close to the air shaft in going to the hoisting shaft, and when they encountered the smoke and gases in that vicinity a number turned hack and climbed down with the direction of the air currents and were then suffocated, while all those who passed through the relatively short pall of smoke to the main shaft were saved.

Jan 2, 1917

By Arthur O. Gates

RittingeR's law of the energy expended in crushing is, as roughly stated by Profcssor Richards,' that the work of crushing is proportional to the reduction in diameter; or, as I have more fully expressed it: "The work done in crushing is proportional to the surface exposed by the operation; or, better expressed for this purpose, the work done on a given mass of rock is proportional to the reciprocal of the diameter of the final product—assuming that all the mass has been reduced to one exact sine, which is only theoretically possible."² Kick's law is stated by H. Stadler as follows :3 "The energy required for producing analogous changes of configuration of geometrically similar bodies of equal technological state varies as the volumes or weights of these bodies." In other words, the energy expended is proportional to the volume reduction, instead of the diameter reduction. That these two laws would give widely different results may be shown by a simple imaginary case. A ton of 16-in. cubes is broken to 1-in. cubes at the first operation, and these are broken to 1/16. cubes at a second operation. Since the first operation produces only one-sixteenth as much new surface as the second, the ratio of energy expended in the two operations would be by Rittinger's law as 1 to 16. By Kick's law, since the volume-reduction ratio is the same in both cases, the ratio of energy would be 1 to 1. This discrepancy is great enough to challenge a test by actual experiment, of which there has been, hitherto, but little compared with the amount of argument. The present paper is the record

Jan 1, 1916

By J. D. Miller, M. Misra

The processing strategy for the effective separation of bitumen from low grade (<l0 weight percent bitumen) Utah tar sands by a hot water process differs significantly from that used for the processing of high grade (> 10 weight percent bitumen) Utah tar sands. Excellent separations (coefficient of separation = 0.9) can be achieved for high grade Utah tar sands by intense hot water digestion followed by a modified froth flotation step. Such a technique is ineffective for low grade tar sands. In order to change the characteristics of the low grade tar sand an attempt was made to enrich the bitumen content of the feed to greater than 10 weight percent by recycle of bitumen concentrate to the digestion stage. However, the quality of the separation was not improved under these circumstances. Similarly feed enrichment by heat treating the low grade feed with recycled concentrate prior to digestion did not improve the separation. More successful separations of low grade Utah tar sands were finally achieved by modification of the viscosity of the low grade bitumen with controlled addition of diluent. These results of the hot water separation tests and variations in the quality of separation are interpreted in terms of the physical properties of the bitumen and the surface bonding forces operative at the bitumen-sand interface.

Jan 1, 1981