Search Documents

By R. C. Thompson

THE lead-zinc mill of Phelps Dodge Corporation, Copper Queen Branch, Mines Division, Bisbee, Arizona, is about 3 miles from the main hoisting shafts of the Junction and Campbell mines at Lowell. All the ore treated in the mill is obtained from these two mines. The mill was designed for an all-flotation treatment of 450 tons of lead-zinc ore per day, and has been operated at that capacity since the start of milling operations on Nov. 17, 1945. An expansion program is underway whereby the mill capacity will be doubled, but this article describes only the original program and presents results of the 45o-ton operation. GENERAL DESCRIPTION The milling plant consists of an ore-receiving bin and three steel-constructed buildings housing, respectively, the primary crushing equipment, the secondary crushing equipment, and the ore-storage bins, grinding, flotation, and filtering equipment. The mill site is the one that was used for a previous copper-concentrating plant, which was operated over a period of years and then dismantled. There remained from this operation some milling equipment, a reservoir for mill-water supply, railroad tracks, tailings-disposal ponds, and a steel-constructed building, all of which were incorporated in the design of the present lead-zinc mill. The location plan of the plant layout is shown in Fig I. The flowsheet of the mill is based on the conventional scheme for lead-zinc treatment, however, several innovations were made necessary in order to utilize the existing building. Placing of equipment also was governed by the design of the building; thus making the mill unique in many respects. The following brief description of the mill building as adapted to the flowsheet points out the compactness of the installation and some of its unusual features. The first floor (Fig 2) houses the grinding equipment, with connecting conveyors for ore feeding, also an air compressor, two vacuum pumps, bins for lead and zinc concentrate storage with individual conveying systems for loading the two kinds of concentrates. Filtering of concentrates is done on the second floor, the concentrates discharging directly into the concentrate-storage bins. On this floor are the lead and zinc filters, two diaphragm pumps, sample-filtering equipment, sample-preparation room and a change room for the mill employees. The flotation machines are on the third floor, at elevations allowing a gravity flow of the lead and zinc concentrates to the thickeners. The annex to the building contains a freight elevator and provides space for all reagent mixing and feeding, also storage of reagents and grinding balls. All the water used for milling purposes is pumped from the Junction mine and

Jan 1, 1947

By Hugh Henton

THIS paper is the result of an investigation made in association with Dr. Charles H. Fulton. Early in 1918 a search was started for methods of utilizing, in the manufacture of basic refractories, certain domestic resources in magnesites, dolomites, and magnesian limestones. Much information was collected during that year and during 1919 regarding magnesite and dolomite deposits. During 1920 and 1921 a research was made into methods of calcining dolomite and separating magnesia therefrom. Some success was attained and many new ideas were brought out in connection with the preparation and utilization of magnesia in the form of "caustic" or light-burned material as well as in the form of refractory or "dead-burned" material. Stimulated by this success, much advance has been made in manufacturing processes for the "plastic magnesia," so called, used for magnesia cement, stucco, flooring and otherwise in the structural industries.

Jan 3, 1926

By C. J. Rosa, W. C. Hagel

An attempt is made to determine the diffusion coefficients of oxygen ions in hypostoichiometric zirconium oxide. A phenomenological theory is developed for three-phase, unidirectional volume diffusion of a gaseous species from a planar source. Knowledge about oxygen diffusion in a and ß zirconium and experimentally measured rates of movements of interfaces permit the evaluation of oxygen ion diffusivi-ties in ZrO2-x. The results conform to the relationship: sq cm per sec, for the temperature range of 875" to 1050° C. DIFFUSION coefficients of oxygen ions in stoichio-metric oxides have been studied by many investigators. The obtained results not only supplement the knowledge about the lattice-defect structures of oxides and conduction mechanisms but also provide information of technological importance. Rate processes such as oxide sintering, high-temperature creep deformation, and oxidation of metals and their alloys are directly dependent on diffusion phenomena. Unfortunately, diffusion coefficients obtained from studies on stoichio-metric oxides cannot be treated without restraints when applied to oxidation kinetics, if precise evaluations of oxidation rates are desired. Oxides formed on metals are usually nonstoichiometric and exhibit nonuniform distribution of either cation or anion vacancies across their thicknesses. Debuigne and Lehr1 extended Danckwerts'2 mathematical analyses and furnished a semitheoretical treatment for evaluating oxygen diffusion coefficients in zirconium oxide in terms of weight gain measurements during oxidation of zirconium in the temperature range 400° to 850°C. Their calculations are based on theoretical partitioning3 of the total amount of oxygen between a zirconium and its oxide phase. An inherent discrepancy appears to continue throughout their calculations. The amount of oxygen confined to the oxide phase should be corrected by multiplying the calculated oxide thickness by the inverse of Pilling-Bedworth ratio, if expansion of zirconium dioxide is taken into account. The purpose of the present investigation is to provide a new semitheoretical treatment for evaluating diffusion coefficients of moving species in hypostoichiometric oxide. The analyses are relevant to unidirectional volume diffusion. Although the presented method is quite general, its applicability will be discussed in terms of kinetic measurements from oxidation of zirconium at temperatures above the a/ß transition, for reasons stated in the later part of this paper. EXPERIMENTAL Pure, 99.93 wt pct, zirconium samples of approximately 2 by 1 by 0.35 cm were exposed to oxygen for various times at four temperature levels: 875°, 950°, 1000°, and 1050°C. High-purity, better than 99.9 vol pct oxygen was passed through a cold trap and columns containing anhydrous CaSO4 to remove residual water vapor. Before exposing to oxygen at a pressure of 500 Torr, specimens were subjected to wet abrasion on 200- through 600-grit Sic papers and polished with 1—p diamond dust. Prior to oxidizing, all zirconium samples were vacuum-annealed at 10-6 mm Hg for about 15 min at the test temperature. The temperature variation across the uniform heat zone was ±2°C from the preset value. Final polishing, for phase thicknesses measurements, was performed by using 8- and 1-p diamond dust and followed by vibrator polishing with 0.05-µ ? Al2O3 solution. Measurements of phase thicknesses were made by projection on a metallographic viewing screen. Conventional powder X-ray analyses for the oxide were employed. RESULTS Fig. 1 is an example of the cross section of oxidized zirconium. Designations of phases given below this figure are the same as those used in the three-phase diffusion system represented by Fig. 5 in the following section. Zirconium oxidized for longer exposure times showed two types of oxides: white oxide at the surface and an underlaying layer of gray oxide. X-ray powder patterns of these oxides at room tern-

Jan 1, 1969

By G. Birkbeck, T. C. Wells

Pearlite morphology in three commercially produced, low-carbon steels has been studied using optical and electron microscopy. A reduction in the cooling rate from 600° to 6°C per hr increased the interlamellar spacing but had little effect on pearlite content. The form of the lamellae was also assessed in terms of a new parameter, the ratio of lamellae length to interhmellar spacing. The variation of this parameter with cooling rate depended on steel composition. For each steel, it would appear that an optimum cooling rate exists at which lamellar pearlite can be produced to the greatest extent, though not necessarily the same extent in different steels. PeARLITE morphology depends principally on steel composition, prior austenite grain size, and either cooling rate or isothermal transformation temperature. Alloying with manganese,'" fine grain size,374 and slow cooling rates reduce the likelihood that a well-developed lamellar structure will be produced. Instead, imperfect structures usually consisting of partly globular carbides are formed in a ferrite matrix. Such structures have been described as granular.1,2,5 degenerate,6 or semi4-pearlite. Manganese additions also progressively lower the eutectoid temperature and the carbon concentration at the eutectoid so so that, for a given carbon content. the pearlite fraction is increased as manganese is added. While the effects of manganese are understood in a general way, quantitative studies of pearlite morphology have been carried out mainly on steels of eutectoid composition;9 little quantitative data is available for low-carbon steels. Certain anomalies exist in the behavior of steels containing -1.5 pct Mn, however. The pearlite morphology in niobium-treated steel differs from that which is generally accepted as typical of low-carbon/manganese steels in that a reasonably well developed lamellar structure is sometimes observed. In the present work, the effects of changes in cooling rate from 600° to 6°C per hr on the pearlite morphology in three commercially produced, low-carbon steels have been studied by both optical and electron microscopy. I) MATERIALS The steels were of the following types: 1) 0.1 pct C, 0.4 pct Mn steel (En 2, a composition similar to specification SAE 1010); 2) niobium-treated, 0.2 pct C, 1 1/2 pct Mn steel (BS 968:1962); 3) silicon-killed 0.2 pct C, 1 1/2 pct Mn steel (En 144, a composition similar to SAE 1320). The chemical analysis for each steel is given in Table I. To facilitate the comparison of pearlite morphology in the three steels, steels 1 and 3 (which were obtained as 1/2-in. plate and 1-in.-diam bar, respectively) were hot-rolled in the laboratory to $ in. thickness, finishing at around 850°C. The BS 968:1962 was received as 1/8-in. plate finished at 885°C and was not further worked. Specimens from each steel were heat-treated in vacuo at 950°C for 1 hr and cooled at rates of 600°, 60°, and 6°C per hr. 11) EXPERIMENTAL Pearlite contents were determined by point counting (500 points) on longitudinal sections mechanically polished and etched in 2 pct nital. Pearlite morphology is usually considered in terms of interlamellar spacing. For pearlite colonies randomly distributed in space and having a true, constant interlamellar spacing So Pellissier et al.9 determined the distribution curve for the apparent spacings of the lamellae on a random section plane. The areal fraction fs of the pearlite colonies occupied by apparent spacings up to a limiting value S is given by:

Jan 1, 1969

By W. D. Lowry

As most of the industrial activity of Oregon is centered in the Portland area, the foundries there consume the bulk of the foundry sand produced in Oregon. Although a number of the larger towns scattered throughout the state have gray-iron foundries, the sand used by most of them is of local origin. The yearly consumption of foundry sand of all types for the past few war years in Oregon is estimated to have been approximately 40,000 tons valued at about $285,000, of which an estimated 18,000 tons was shipped in from the Ottawa, Ill., district for use largely by the steel foundries. Until 1945 much of the silica sand consumed by the steel foundries in the Pacific Northwest, approximately 50,000 tons in 1944, came from Ottawa, Ill. and surrounding regions. Although some silica sand was shipped in from Belgium in the past, none is known to have been imported in recent years. Early in 1945, a very promising high-grade silica sand being produced near Eugene, Oregon, was introduced, and all but two of the Portland steel foundries are using this new sand. Until a few years ago, the search for good local (Oregon) foundry sands was carried on largely by the foundry supply houses. Recently the Oregon Department of Geology and Mineral Industries has investigated a number of deposits and has carried on and fostered research on the most bromising deposit near Eugene, about 120 miles south of Portland. High-grade silica foundry sand from this deposit is now being marketed in Oregon, Washington, and British Columbia. The Eugene sand is one of the very few outstanding western steel-foundry sands. Field investigations by the Oregon Department show that there are relatively few deposits of sand in Oregon suitable for foundry use. A knowledge of the geology of the state makes this readily understandable. The only major primary sources of the quartz present in sandstones in Oregon are the intrusive masses of granite, granodiorite, and quartz diorite of late Jurassic or early Cretaceous age found in the Siskiyou Mountains of southwestern Oregon, a part of the old Klamath Mountain highland, and in the Blue Mountains of northeastern Oregon. Transportation militates against the development of any possible deposits of foundry sand found east of the Cascade Mountains in central and eastern Oregon because few railroads traverse that area. East of the Cascades, which separate western from eastern Oregon, many of the older sediments of Paleozoic and Mesozoic age have either been metamorphosed or contain much volcanic eruptive material, and even if some of the Mesozoic sediments are highly quartzose in places, they are in relatively inaccessible areas. All the Tertiary sediments there are of continental origin and contain much ash and other volcanic debris, for there was great volcanic activity during much of that period. In western Oregon much the same is true of the Paleozoic and Mesozoic rocks

Jan 1, 1948

By W. D. Lowry

As most of the industrial activity of Oregon is centered in the Portland area, the foundries there consume the bulk of the foundry sand produced in Oregon. Although a number of the larger towns scattered throughout the state have gray-iron foundries, the sand used by most of them is of local origin. The yearly consumption of foundry sand of all types for the past few war years in Oregon is estimated to have been approximately 40,000 tons valued at about $285,000, of which an estimated 18,000 tons was shipped in from the Ottawa, Ill., district for use largely by the steel foundries. Until 1945 much of the silica sand consumed by the steel foundries in the Pacific Northwest, approximately 50,000 tons in 1944, came from Ottawa, Ill. and surrounding regions. Although some silica sand was shipped in from Belgium in the past, none is known to have been imported in recent years. Early in 1945, a very promising high-grade silica sand being produced near Eugene, Oregon, was introduced, and all but two of the Portland steel foundries are using this new sand. Until a few years ago, the search for good local (Oregon) foundry sands was carried on largely by the foundry supply houses. Recently the Oregon Department of Geology and Mineral Industries has investigated a number of deposits and has carried on and fostered research on the most bromising deposit near Eugene, about 120 miles south of Portland. High-grade silica foundry sand from this deposit is now being marketed in Oregon, Washington, and British Columbia. The Eugene sand is one of the very few outstanding western steel-foundry sands. Field investigations by the Oregon Department show that there are relatively few deposits of sand in Oregon suitable for foundry use. A knowledge of the geology of the state makes this readily understandable. The only major primary sources of the quartz present in sandstones in Oregon are the intrusive masses of granite, granodiorite, and quartz diorite of late Jurassic or early Cretaceous age found in the Siskiyou Mountains of southwestern Oregon, a part of the old Klamath Mountain highland, and in the Blue Mountains of northeastern Oregon. Transportation militates against the development of any possible deposits of foundry sand found east of the Cascade Mountains in central and eastern Oregon because few railroads traverse that area. East of the Cascades, which separate western from eastern Oregon, many of the older sediments of Paleozoic and Mesozoic age have either been metamorphosed or contain much volcanic eruptive material, and even if some of the Mesozoic sediments are highly quartzose in places, they are in relatively inaccessible areas. All the Tertiary sediments there are of continental origin and contain much ash and other volcanic debris, for there was great volcanic activity during much of that period. In western Oregon much the same is true of the Paleozoic and Mesozoic rocks

Jan 1, 1948

GENERAL GEOLOGICAL DESCRIPTION The uranium mineral appraisal herein described was made for an ore deposit in New Mexico. The uranium mineralization occurs as roughly tabular to lens-shaped deposits of varying thickness within the sandstone of the Jackpile formation of Jurassic age. The mineralization occurs at several horizons within the Jackpile formation, but is not always confined to specific beds. It often transgresses across stratigraphic layers, as demonstrated when attempting correlation of uranium gamma anomalies between adjacent drill holes. Preferred mineral trends have been established in some parts of the deposit, but are not always predictable when attempting to extrapolate beyond the zones defined by drill hole sampling. MANAGEMENT OF DRILL HOLE SAMPLE DATA All of the drill hole sample data used in the appraisal were obtained from interpretation of gamma-ray logs. A brief description of gamma-ray log sampling is given in Chapter 2. Two preliminary steps are involved in preparing gamma-ray logs into sample data normally acceptable for computer manipulation. 1) The gamma analog trace produced by the downhole probe must be digitized, i.e., counts-per-second (CPS) are recorded for each 0.15 m (1/2-ft) interval across the gamma-ray anomaly. The work is usually done on a "digitizer" while following the analog trace with an electronic stylus on a special tablet or table. The other alternative is to do the work manually. Some of the newest downhole logging equipment produces a magnetic tape output which can be read by a computer. 2) The gamma-ray CPS values must then be converted to equivalent U308 assay values, taking into consideration all appropriate correction factors. The US Atomic Energy Commission, now part of the Department of Energy, developed the theory and algorithm for this conversion in the 1960's, and though the work can be done manually, it is best done with the GAMRED (gamma-reduction) computer program. Fig. 14-1 illustrates a typical analog trace produced by the probe instrumentation, including gamma-ray trace (left), self-potential electric log (center), and resistivity log (right). Fig. 14-2 shows a form of the computer output after the analog data has been digitized to 0.15-m (1h-ft) intervals and converted to percentage U308 values for the same hole. The U308 grade bar graph on the right permits rapid visual inspection of anomalous values by depth and elevation. The converted U308 sample data were next processed by the SURVEY program that assigned to each assay interval [0. 15-m (1h-ft)] an X Y Z coordinate, taking into account all deviations indicated from downhole survey information. The output file of the SURVEY program was listed on the line printer for examination by project geologists, and also became the main input file for the URAN/ COMP compositing program, which is designed to group individual 0.15-m (/-ft) U308 sample values into larger intervals representing discrete anomalous zones according to a series of specified parameters entered into the program by the user. Composite U308 intervals were computed by the URAN/COMP computer program, the logic of which may be briefly described as follows: Step 1 The program searches for the highest U308 value in the hole and builds a composite by adding the highest grade interval on either side so long as the added value is greater than a minimum acceptable grade, and the total composite, after addition, meets minimum GT (grade times thickness) constraints. Step 2 The program loops back to find the next highest assay value in the hole not already included into a composite, until all anomalies above minimum cutoff grade are composited. Step 3 Individual composites are combined if they are closer than a specified minimum waste thickness, and the resultant composite grade still meets GT minimums.

Jan 1, 1980

By Arthur F. Wendt

The following experiments and researches were originally conducted by Dr. Heinrich Rcessler, chief of the German Gold and Silver Parting Establishment at Frankfort-on-the-Main, for the sole purpose of abating the nuisance created by the discharge into the air of the sulphurous and sulphuric acids generated in the process of parting bullion by sulphuric acid. The results achieved have, however, an important bearing not only on this process, but are of value in the manufacture of sulphuric acid and sulphate of copper from sulphurous gases derived from any source. It has now been in successful operation for a term of years at Dr. Roessler's own works, and has been lately introduced with satisfactory results at the royal mints of Kremnitz and Munich, and the well-known establishment of Johnson Mathey & Co., of London.

Jan 1, 1884

By J. L. Wyatt

THE smelting of ilmenite to produce a slag rich in titanium, with pig-iron as a byproduct, introduces new concepts in electric smelting metallurgy. Titanium slags are characterized by low electrical resistance, thereby requiring a different type of electric furnace operation, and power supply sources substantially different from those encountered in normal steel melting and siliceous ore smelting furnaces. This paper describes special apparatus for determining specific electrical resistivity of titanium slags, and reports the values obtained on slags encountered in the process of smelting ilmenite ores. In an induction furnace under conditions approximating normal furnacing operation, 25 general heats and 6 special standardization and comparison heats were run. Results indicate relatively low resistivity. Resistivity depends primarily on slag composition, and, to a lesser degree, on temperature. During the summer of 1947 a cooperative project between the National Lead Co. and the Bureau of Mines was conducted at Boulder City, Nevada, in the Electrometallurgical Laboratories of the Bureau. The project involved smelting of ilmenite ores in electric furnaces, and has been reported in detail.' The author participated as a member of the staff of the National Lead Co. during the entire campaign. One outstanding characteristic of the titaniferous slags, their apparently excellent and variable electrical conductivity, was considered sufficiently important to warrant further study. Although little electric smelting of iron ores has been done in the United States, a certain amount of information is available for comparative purposes. Personal experience in smelting siliceous iron ores in electric furnaces furnished further information for comparison. In general, silicate slags are relatively poor conductors of electricity. Current flow during smelting operations may be maintained through a floating layer of coke on top of the slag bath, or through a bath of molten iron, beneath the slag. Silicate slags are not sufficiently conductive to furnish a path for current passage when normal furnace voltages are used. Experimental smelting of a silicate iron ore was undertaken for comparative purposes. A fluid melt was not obtained until the FeO content was reduced to 15 pct. The resistivity increased as the FeO content decreased, FeO compounds being the most conductive of the various oxides in such a normal slag system. The converse appears to be true in slags containing large percentages of TiO2. It has been found that titanium slags become molten with FeO percentages in excess of 30 pct, and that the conductivity becomes generally better as the FeO con-tent of the slag diminishes. This phenomenon was demonstrated in the furnacing operations at Boulder City. During the initial smelting period furnace electrodes could be held immersed several inches in the slag, with tap selectors set for a no-load voltage of 70 v. As the FeO content decreased, the furnace electrodes would "walk up," until at one point in the process the tips would break the surface and arc on top of the slag. This was undesirable since direct arcing caused losses of important flux additions. The slag compositions under study at that time were such that losses due to surface arcing sometimes caused viscous slags to be formed. Forcing the electrodes into the slag bath by manual control to prevent surface arcing resulted in excessive power input and lack of control. Suitable low voltages were not available. Measurement of the electrical resistivity of titanium slags at various operating temperatures and slag compositions was undertaken. It was believed that this information would be of use in the design of electric furnaces suitable for smelting ilmenite, with voltages, electrode sizes, and electrode spacing adapted specifically to titanium slags.

Jan 1, 1951

By K. A. Gschneidner, O. D. McMasters, T. J. O’Keefe

X-ray diffraction, differential thermal, ad rnetallo-graphic methods were used to establish the Dy-Pb Phase diagram. Lead additions lower the 1377°C transformation temperature of dysprosium to 1360°C leading to an inverted peritectic reaction. The 327°C melting point of lead is lowered by dysprosium additions to about 326°C yielding a eutectic reaction. A second eutectic reaction occurs at 13.3 at. pct Pb and 1200°C. The dysprosium-richest intermetallic compound DysPb3 melts congruently at 1695°C and crystallizes in the hexagonal Mn5Si3 (D8,) type structure. The peritectic decomposition temperatures for the remaining compounds are Dy5Pb, at 1555C, DyPb2 at 955C, and DyPb3 at 880°C. A fifth compound near the DyPb stoichiometry exists over a 310°C temperature range decomposing at 1130°C by means of an inverted peritectic reaction and melting incongruently at 1440°C. The crystal structures of the compounds are discussed. A systematic study of the rare earth-lead alloy systems is underway in an effort to supply information concerning the alloying behavior of the rare earth metals. The Dy-Pb phase diagram is the fourth system to be investigated in this study. The Yb-Pb,1 Y-Pb,2 and Eu-Pb 3 diagrams have been published recently. Utilization of the rare earth series of metals as a research tool in this manner should yield a better understanding of alloy formation. EXPERIMENTAL PROCEDURE Materials. The lead used in this investigation was obtained from Cominco Products, Inc., and was specified to be 99.99 pct pure. The dysprosium was prepared in this Laboratory by the calcium reduction of the fluoride followed by distillation of the dysprosium. The major impurities in the dysprosium in ppm are: A1 (<40), Ca (400), Er (<50), Gd (<200), Ho (<200), Mg (<50), Si (30), Ta (400), Tb (<100), Y (<50), 0 (651, H (15), N (not detected), F (430), C (35). Alloy Preparation. Most of the alloys were prepared by melting weighed amounts of dysprosium and lead in sealed tantalum crucibles. The tantalum crucibles were sealed by are-welding in a He-Ar atmosphere welding chamber. Thus the alloys are in contact with He-Ar at about 1 atm pressure. Homogenization was achieved by holding them in the liquid state for about 1 hr, cooling, inverting the crucibles, remelting, and repeating the process at least twice. Since these alloys were prepared in sealed tantalum crucibles, chemical analysis for final composition was thought to be unnecessary. No detectable reaction of these alloys with the tantalum crucible was observed by metallographic examination. Metallographic evidence was also used to confirm the homogeneity of some of the alloys prepared in this manner. The compositions of a few alloys, which were prepared by nonconsum-able are-melting, were corrected for the small weight losses involved by assuming that the weight loss is due to vaporization of lead. The specimens obtained from the alloy samples were prepared under a dry-argon atmosphere because they were rapidly attacked by air and moisture. Thermal Analysis. Differential thermal analysis methods were used to determine the liquidus curves and reaction horizontals of the system. Both Pt vs Pt + 13 pct Rh and W + 5 pct Re vs W + 26 pct Re thermocouples were used to measure the temperature. An X- Y recorder was used to record the specimen temperature and differential electromotive force between the specimen and molybdenum standard. The arrest temperatures were measured potentiometri-cally. The accuracy limits (* values) associated with the reaction temperatures obtained by this method were estimated on the basis of both the reproducibility of the particular temperature value and the accuracy of the thermocouple at a given temperature. Liquidus temperatures were obtained from cooling arrest data while both heating and cooling arrest data were used to establish the horizontals of the diagram. Heat treatments during the thermal analyses of the alloys between 40 and 70 at. pct Pb were necessary in order to approach equilibrium conditions. The samples were held at temperatures between the various peritectic horizontals for l to 2 hr before the thermal analyses were continued. The entire range of compositions was investigated at the expense of a minimum amount of materials by adding appropriate amounts of lead to master alloys. More than sixty alloys were analyzed by this differential thermal method and for each alloy the results given herein are taken from two or three heating and cooling cycles. X-Ray and Metallographic Methods. Slice specimens for metallography and powder specimens for X-ray diffraction were prepared from rod-shaped samples which had been melted in sealed 0.62 5-cm-diam tantalum crucibles. The specimens were heat-treated in sealed tantalum crucibles which were protected by sealing them in argon-filled quartz ampules. Quenching was accomplished by breaking the ampules in ice water after heat treatment. X-ray powder specimens were sealed in 0.3-mm-diam glass capillaries under a dry-argon atmosphere. Copper, iron, and chromium radiation were used to obtain the powder patterns for these alloys. More than 150 powder patterns were obtained for specimens of various compositions and heat treatments. Included in these were several patterns for specimens which had purposely been oxidized. Patterns from specimens which had been accidentally exposed

Jan 1, 1969

By K. S. Lane

The problem of stability of slopes in reservoirs is one of real interest in civil engineering. The problem is whether the valley walls will remain stable or whether they are likely to slide as conditions are changed by storage of water in the reservoir. If major slides are indicated, as on the walls of relatively steep canyons, one must estimate whether they will be so located and of sufficient size as to interfere with operation of the reservoir-as by blocking the outlets, or by displacing sufficient water to over-top the dam in a huge wave. Some cases involve problems in soil mechanics for slides in earth or weaker rock; other locations need the assistance of rock mechanics for slides in harder rock. While this is not a new problem, attention has recently been focused on its importance by the hugh landslide into the Vaiont reservoir in 1963, which claimed the lives of over 2000 people and forced abandonment of the dam and powerhouse. VAIONT RESERVOIR SLIDE Fig. 1 shows Vaiont Dam in Italy which is a double curvature arch, 875 ft high, located on a tributary of the Piave River, north and west of Venice. When completed in 1960 it was the highest arch dam in the world. In 1960 a sizable landslide (some 700,000 cu yd) occurred on the left abutment a short distance above the dam. Following this, the reservoir was held down for construction of a by-pass tunnel through the right valley wall to insure connection with the upper end of the reservoir in event of further slides. In October 1963 a giant landslide occurred on the left valley wall, over a width of some 14 miles (see Fig. 2). Over 300 million cu yd slid into the reservoir, displacing the water and forming a hige wave 700 ft above the top of the dam as it hit the opposite, or right, wall of the valley. The wave then passed some 500 ft over top of the dam, followed down the tortuous winding canyon and debouched into the

Jan 1, 1967

By John D. Ridge

For mining geologists, the most important trends during 1962 have been the increased concentration of the exploratory activities of American mining companies in the United States and Canada and the greater use of the combined techniques of geology, geophysics and geochemistry in searches over larger areas for wider varieties of metals and minerals. The principal reasons for these changes in approach have been the deterioration of the political-economic climate in many areas of the globe of equal or greater geologic promise and the realization that modern exploration is most efficiently and economically conducted through the use of all available means of detecting ores in areas sufficiently large to raise to a maximum the chances of success. The attitude of certain major U.S. metal-producing companies can be shown by the officially ex- pressed positions of their principal officers. Early in 1962, Clyde E. Weed, Chairman of the Board of Anaconda, remarked that "because of unsettled conditions and disruptive influences in many of the copper-producing areas of the world, it is imperative that domestic copper-producing capacity be improved and made as efficient as possible in order to meet consumer demands at reasonably stable prices." In November, Robert G. Page, President of Phelps Dodge, pointed out that his company is not only concentrating most of its exploratory effort on this continent but is also increasing the number of metals for which it is searching. Frank R. Milliken, President of Kennecott, recently said that "most of our exploration money is going into the northern part of the Western Hemisphere."

Jan 2, 1963

By W. L. Crentz, E. E. Donath, D. Doherty

Maurice Rey—The influence of cyclone diameter upon the fineness of separation is an important point which, however, cannot be discussed adequately if the injection pressure or the rate of flow are not specified. Perhaps some light can be thrown on the matter by using the formulas derived by Dahlstrom. Let us consider several geometrically similar cyclones where the apertures e and b are equal and proportional to the diameter D and which are operated with the same pressure drop. Eq 8 of Dahlstrom&apos;s paper can be written: Q Q = K D&apos;. " or. if F is constant: Q = K D18 K is a constant of proportionality. Introducing this value of Q in eq 13 gives elimination efficiency = K D0&apos; " Elimination efficiency, in the terminology of Dahlstrom, means the diameter of particles, in microns, which divide equally between the underflow and the overflow. This denomination is regrettable and it would be preferable to call it diameter of separation or characteristic size or any other name connoting a size rather than an efficiency. Whatever the name used, the above equation shows a slow increase in the fineness of separation when the diameter of the cyclone decreases. For example, if a 14-in. cyclone gives a 400-mesh separation (37 microns), geometrically similar cyclones, having the same pressure drop will give separations at the sizes shown below.

Jan 1, 1951

By E. E. Donath, W. L. Crentz, D. Doherty

Maurice Rey—The influence of cyclone diameter upon the fineness of separation is an important point which, however, cannot be discussed adequately if the injection pressure or the rate of flow are not specified. Perhaps some light can be thrown on the matter by using the formulas derived by Dahlstrom. Let us consider several geometrically similar cyclones where the apertures e and b are equal and proportional to the diameter D and which are operated with the same pressure drop. Eq 8 of Dahlstrom&apos;s paper can be written: Q Q = K D&apos;. " or. if F is constant: Q = K D18 K is a constant of proportionality. Introducing this value of Q in eq 13 gives elimination efficiency = K D0&apos; " Elimination efficiency, in the terminology of Dahlstrom, means the diameter of particles, in microns, which divide equally between the underflow and the overflow. This denomination is regrettable and it would be preferable to call it diameter of separation or characteristic size or any other name connoting a size rather than an efficiency. Whatever the name used, the above equation shows a slow increase in the fineness of separation when the diameter of the cyclone decreases. For example, if a 14-in. cyclone gives a 400-mesh separation (37 microns), geometrically similar cyclones, having the same pressure drop will give separations at the sizes shown below.

Jan 1, 1951

By R. J. Brison, W. C. Bleimeister

The International Salt Company has long been interested in finding an efficient process for the removal of impurities from rock salt, and particularly from the rock salt produced at the Detroit mine. Methods which have been used previously at the Detroit mine included both hand sorting and differential crushing in a Bradford breaker with rejection of the oversize. Neither of these methods was adequately effective. The development of a new process for removal of impurities from rock salt has been described in the preceding article." Basically, the process consists of exposure of crude rock salt to radiant heating which selectively heats the impure particles. Subsequently the heated particles are removed by adhesion to a heat sensitive-coating on a conveyor belt. This method was found to be effective in improving both the quality and appearance of rock salt by the rejection of the dark, impure particles.

Jan 8, 1960

By Forbes Wilson

IN February 1952 Freeport Sulphur Company started exploration work on a group of lateritic deposits at Moa Bay, Cuba. As a result of successful exploration work and a vast amount of metallurgical research over the past five years, these deposits will soon become a new Free World source of nickel and cobalt. Moa Bay lies on the north coast of Oriente Province, the easternmost part of the island, about 600 miles east of Havana and about 40 miles east of the U. S. Government nickel plant at Nicaro.

Jan 5, 1958

By R. Schuhmann, O. W. Moles

at temperatures of 1150°, 1250°, and 1350°C for liquid copper sulphides ranging in composition from saturation with Cu to about 21.5 pct S. From the experimental data, activities of Cu, S, and Cu2S in the melts were calculated. Also, the results furnish a new determination of the location of the curve showing the compositions of Cu-saturoted sulphide melts in the CU-S constitution diagram. THE "white metal" made as an intermediate L product in converting copper matte to blister copper is a matte approximating Cu2S in composition. It has long been known that liquid Cu-S mattes can exist at a given temperature over an appreciable composition range, with S:Cu ratios ranging up from a lower limit corresponding to equilibrium of the matte with a liquid Cu phase. The Cu-saturated matte has somewhat less S than Cu2S, although previous measurements of the compositions of Cu-saturated mattes are not in good agreement.&apos;" As the S:Cu ratio approaches and slightly exceeds that for Cu2S, the partial pressure of sulphur gas over the liquid matte rapidly approaches atmospheric pressure,5 so that Cu-S melts with much more S than Cu2S can be made and handled only in pressure apparatus. Accordingly, the liquid copper sulphides of interest in copper smelting and readily studied experimentally fall in a relatively narrow composi- tion range about Cu2S. The freezing points of Cu-S mattes show a maximum of 1129°C near the composition Cu, dropping to 1105oC for Cu-saturated mattes having less S and dropping under 1100°C for higher S mattes.&apos; Estimates of the sulphur pressure and other thermodynamic properties of liquid Cu,S were made by Kelley; based on extrapolations from equilibrium measurements on solid Cu,S. More recently, Cox and coworkers&apos; studied equilibria in the reaction: Cu,S + H, e 2Cu + H,S over the temperature range 700" to 1250°C. They measured equilibrium H2S:H2 ratios presumably with both the sulphide and the metal phase present, so that their data above the melting point of Cu,S should measure the S pressure of Cu-saturated sulphide melts. The sulphur pressures of liquid copper sulphides of several S:Cu ratios at their freezing points can be estimated from data given by Posnjak, Allen, and Merwin." However, beyond these few data, no systematic study seems to have been made of the relations of sulphur pressure and other chemical properties of liquid copper sulphides to composition and temperature. The measurements of the sulphur pressures of liquid copper sulphides reported in this paper represent a first step in the quantitative study of the chemistry of mattes. Similar work is planned on

Jan 1, 1952

By K. E. Gray

The status of rock mechanics as applied to petroleum production might be termed, "Rock Mechanics-A New Name for Old Problems." The petroleum industry&apos;s efforts, from its earliest days, have been concerned with rocks, hopefully containing hydrocarbon accumulations in economic quantities. Geophysical and geological studies, wildcat and development drilling procedures, well bore mechanics and reservoir engineering operations, and certain aspects of production operations involve rock mechanics in various ways. Stress states and temperatures of interest range from low values in surface or near-surface activities, to very high values encountered at depths now exceeding 25,000 ft; deeper and deeper drilling will continue to increase this range. Time scales vary from a few microseconds in wave propagation measurements and some aspects of rock behavior during drilling, to seconds, minutes or hours for other drilling and well bore mechanics problems, to several years during which the efficient and economical depletion of reservoir systems is achieved. Subsurface sedimentary formations contain various fluids, of course, and reservoir fluid movement commonly involves three-dimensional, three-phase (oil, gas, and water) fluid flow. Many extremely difficult problems in rock mechanics arise for the Petroleum Engineer because of fluid movement (or lack of desired movement) in a well bore or reservoir. The discussion to follow illustrates just a few of the many topics in rock mechanics of significance to the petroleum industry. Time precludes anything other than a superficial treatment of the topics mentioned. A great deal of work has been carried out by various research groups in the petroleum field and significant efforts are continuing, as a review of the technical literature will reveal.

Jan 1, 1968

By John M. Lovejoy

CURRENT production of petroleum on such a vast scale presents many interesting problems- the solutions of which are important not only to those directly interested in the business, but to the nation as a whole. The industry is relatively young. Until the discovers of the Lucas gusher at Spindletop in 1901 petroleum production had not exceeded 60,000,000 bbl. per year compared with 1,100,000,000 bbl. in 1936. In 36 years then, the modern oil business, production, transportation, refining, and marketing has developed. I will first present a brief history. of oil production as a background for consideration of the present situation.

Jan 1, 1937

By Robert L. Akre

When Marco Polo visited China in the 13th century, no one knew what black powder was except the Chinese: they knew enough to make dazzling fireworks with it. But the realization that black powder could also do useful work came much later and, like all important discoveries, it altered the course of history. It was in the 14th century that black powder was first used to break rock in a very crude way: there were no drills and the powder was simply poured into cracks and exploded by setting it afire. Because its energy value was pretty low, the need for something more powerful was felt when the industrial revolution arrived.

Jan 6, 1976