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By Michael J. Friedel

The scale-dependent hydraulic properties in a fractured porphyry copper oxide deposit are investigated for relevance to in situ leach mine (ISLM) design. In most well field designs, mine operators assume that hydraulic properties represent a continuous spatial function, or continuum. The problem, however, is that the representative elemental volume, the volume over which hydraulic properties are described as a continuum, is a domain (if it exists) that occurs between end members representing varying degrees of heterogeneity. At the Cyprus Cas a Grande mine, transmissivity fluctuations are spatially correlated suggesting that at the scale of ISLM, the hydraulic process is heterogeneous and a typical continuum representation is inappropriate for design. Alternatively, a conditional stochastic approach using the simulated annealing (SA) technique is deemed useful for the imaging of heterogeneous hydraulic properties. Specifically, SA preserves transmissivity extremes and spatial complexity, both necessary for accurate conditioning of a flow simulator. Also, the stochastic continuum approach provides an avenue whereby uncertainty (or risk) may be addressed. Currently, the SA weaknesses are that it is computationally time consuming, and uncertainty may increase when simulating under conditions of statistical isotropy. Recognizing that ISLM exerts a dynamic influence on hydraulic properties with time, the mine design should be reevaluated at intervals throughout the evolution of the leaching process.

Jan 1, 1993

By Y. Guan

The dissolution behavior of copper and gold from their pure state and from Au/Cu alloys in cyanide solutions has been investigated using a rotating disc. Oxygen was used as an oxidant. The effect of the composition of the alloys, stirring speed of the disc, concentration of lixiviants and temperature on the overall dissolution kinetics has been studied. Gold/copper alloys of three compositions were used in this study. The atomic percent of gold in these alloys was 75, 50 and 25, respectively. The dissolution behavior of these three alloys was compared with that of pure gold and of copper under the same chemical conditions. In general, the dissolution of copper and gold from alloys is partially controlled by surface chemical reaction and largely by mass transfer.

Jan 1, 1992

By A. Cecala, J. Noll, J. Organiscak

Many underground metal/nonmetal mines are using enclosed cabs on mining equipment to reduce the exposure of miners to diesel particulate matter (DPM). However, some enclosed cab systems may not be meeting their expected efficiency in capturing DPM, which could be a result of inappropriate filter use, cab leaks or insufficient pressurization. NIOSH investigated several types of filters for reducing DPM to determine which type had the best capture efficiency. The laboratory results indicated that a MERV 8 (minimum efficiency reporting value, as defined by the American Society of Heating, Refrigerating and Air- Conditioning Engineers) filter captured about 50% of the DPM, a MERV 16 filter collected 96-98% of the DPM and two HEPA (high efficiency particulate air) grade filters captured over 99% of the DPM. NIOSH also performed a field study to measure the efficiency of two cabs at a limestone mine. The cab filtration systems of a loader and haul truck were found to be over 90% effective in removing DPM, except under certain operating conditions when the efficiency was as low as 41%. A possible reason for the low efficiencies is an open window in the cab, but more studies need performed to obtain a better understanding of the cause and solution of the problem.

Jan 1, 2011

By B. H. Kear, B. J. Piearcey

The orientation and temperature dependence of the tensile and creep propevties oj Mav-M200 crystals halle been determined. Crystals oriented for single slip exhibit ,maximum ductility, minimum work hardening, and least creep resistance, whereas crystals in multiple slip orientations show nzinimu~n ductility, strongest work hardening, and greatest creep resistance. At 1400" and 1600°F there is a marked improzlenzent in creep strength for orientations approaching [001] and [111], indicating that interactions between dislocations gliding in intersecting octahedral slip systems play an important role in creep resistance. At 1800°F the creep strength is much less dependent on orientation, which is rationalized in terms of slip in cube planes as well as octahedral A frequent mode of failure in high-strength cast nickel-base superalloys is by intergranular fracture, particularly along those grain boundaries oriented transverse to the major stress axis. VerSnyder and ~uard' demonstrated that this problem could be overcome by eliminating transverse grain boundaries through unidirectional solidification. Piearcey and versnyder2 made use of this principle in the development of unidirectionally solidified gas turbine blades and vanes, where the growth direction of the columnar grain structure coincides with the axis of principal stress under operating conditions. The present investigation was undertaken to determine if further improvement in properties may be obtained by eliminating grain boundaries altogether, so as to take advantage of the well-known dependence of mechanical properties of single crystals upon the orientation. 1) EXPERIMENTAL PROCEDURE Single crystals of Mar-M200* were grown from the melt under vacuum by a modified Bridgman method. The melt was poured into a preheated alumina mold, and crystal growth was promoted from one end by appropriate gradient cooling. Tensile and creep specimens (2 in. diam by $ in. gage length) were prepared by a series of operations involving electrical discharge machining, precision grinding, and electropolishing. The orientations of the specimens were determined by the Laue X-ray back-reflection method. Tensile tests were carried out in aWiedemann machine with furnace attachment, using a strain rate planes. In all orientations imzpvouement in the strength charactevistics of the material can be induced by heat treatment. Creep ad stress rupture data for (001) oriented crystals are compared with similar data obtailted previously joy random polycvystalline material, and also columnar grained material having a prejevved (001) orientation. The single-crystal )material exhibits both longer rupture life and lower minimum creep rate at all temperatuves, and the rupture elongation is comparable with that in the columnar grained material. From these results it is concluded that single crystals should and useful application in gas-turbine blades and tanes. The optimum orientation for a blade is considered to be with its axis of principal stvess parallel to (001) ou (111). of 0.0001 sec-'. Load and extension were recorded directly on an X-Y recorder. The strain measuring device consisted of extension arms attached to the grips at one end and leading out of the furnace to an LVDT (linear variable differential transformer) at the other. Creep tests were performed using a standard constant load creep frame. 2) DISCUSSION OF RESULTS 2.1) Structure of Alloy. The structure and segregation in as-cast and heat-treated Mar-M200 has been described in detail else where.~ The main features are as follows: the as-cast material is heavily cored, due to pronounced dendritic segregation during solidification; the dendrites are rich in tungsten and cobalt whereas the interdendritic regions are rich in chromium, titanium, nickel, and carbon. The structure consists of -60 vol pct coherent precipitate of y', basically Ni3(A1,Ti), in a matrix of y (nickel-base solid solution), interspersed in the interdendritic regions with minor MC carbides and -y' eutectic. The y' particles, and y-y' eutectic, contain more titanium, aluminum, and nickel, and less tungsten, cobalt, and chromium than the y matrix. Heat treatment partially removes segregation, eliminates the eutectic, refines the y' dispersion in y, and gives additional partially coherent M23Cs carbide. An as-cast crystal, therefore, is composed primarily of two oriented phases (y + y'), whereas the normally heat-treated crystal consists of three oriented phases (y + y' + MZ3Cs). Typical electron transmission micrographs of the y + y' structure are shown in Fig. 1. Crystals grown in the (100) orientation develop a simple unidirectional dendritic structure, Fig. 2, since (100) happens to be the preferred direction of growth for dendrites in this material. Crystals grown in the {110) and (111) orientations, however, tend to promote equal growth, generally in separate colonies, in the two and three geometrically favored (100) growth directions, respectively. In other orientations of growth, a single (100) dendrite direction generally pre-

Jan 1, 1968

By A. A. Hejja

"Liquidus temperature and electrical conductivity data measured on synthetic slags were modelled by the use of neural nets (NN). In this work the applied multilayer feedforward NNs were trained by a conjugate-gradient optimisation for which a three layer formulation was used. Very good fits were obtained for both the liquidus temperature and the conductivity data. The synthetic slags were prepared from pure oxides to represent a wide range of compositions likely to be encountered in ferromanganese and silicomanganese smelting. The slag constituents were in the following range: Mn0;5-30%, Ca0;20-35%, Mg0;5-15%, Si02;27-58%, Al20 3;5%. Liquidus temperatures varied from 1300° to 1380° and increased with increasing basicity ratio. The electrical resistivity of slags decreased with the increase of basicity ratio from 0.55 to 1.1 but above 1.1 basicity ratio the resistivity tended to increase depending upon the MnO content.Neural NetsVarious neural net (NN) topologies such as Hopfied nets, Hamming nets, Carpenter/Grossberg classifiers have been discussed in some detail by Lipmann (1). In this work, the applied multilayer feedforward NNs are not trained by backpropagation (BP) using the generalized delta rule (2) (GDR), but by a conjugate-gradient optimisation [3,4] - a procedure similar to that proposed by Barnard and Cole [5]. A neural net is capable ·of learning the non-linear functional relationship existing between a set of inputs and outputs [ 6]. In this capacity a neural net is used to determine the functional relationship that exists . between N dependent and independent variables, which characterize the system under consideration For a three layer neural net [1] the following function may be formulated, which relates X; inputs to the output Y 0 from node o:"

Jan 1, 1997

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

The thermodynamic behavior of dilute solutions of copper, silver, and gold in liquid tin is not explained by current solution theories.1-3 The relative partial gram-atomic enthalpies, or heats of solution, of silver, gold, and platinum in liquid lead at 623°K have been measured in the investigation reported here. Their interpretation requires a modification of the regular-solution theory although lead-rich solutions may be expected to be simpler than tin-rich solutions. The liquid metal solution calorimeter used has been described.4 At the start of a run the bath consisted of 621 g of reagent-grade lead. Several calibrating additions of lead were made during a run; a value of 3.48 kcal per g-atom5 was taken for H623°K - H273°K Two runs were made with each of the solutes silver, gold, and platinum. Annealed wire samples of 99.999+ pct purity were used. Four to six samples each weighing 0.5 to 1,0 g were added from 273°K to the bath at 623°K and the associated heat effects were measured. The samples dissolved in approximately 3 min. No serious experimental difficulties were encountered. The heat effects of the additions in a run plotted against the average atom fraction of solute before and after each addition314 were linear functions of the concentration in lead of silver, gold, and platinum, respectively. By subtracting the difference between the heat contents of a solute element at 623° and. 273°K5 from the measuredheat effects, the partial gram-atomic enthalpy relative to the solid solute was obtained. The relativ: partial gram-atomic enthalpy at infinite dilution and the concentration dependence of the partial gram-atomic enthalpies obtained from the plots of vs atomic fraction x are listed in Table I. The relative partial gram-atomic enthalpy at infinite dilution of silver in lead of 5.46 kcal per g-atom at 623°K compares with values at 723°K of 5.74' and 5.765 kcal per g-atom. These data yield a temperature coefficient of 3.0 cal per g-atom-OK. The partial gram-atomic enthalpy at infinite dilution of gold in lead at 623°K is 0.89 kcal per g-atom compared with 0.85 kcal per g-atoms (obtained by extrapolation) and 0.95 kcal per g-atom.5 By combining these values for 623°K with those for several other temperatures5" the temperature coefficient of was found to be 3.2 cal per g-atom-OK. No thermodynamic data are

Jan 1, 1968

By C. Kathryn Sole

The close proximity of cobalt and nickel on the Periodic Table and their frequent occurrence together in nature means that their separation in primary hydrometallurgical flowsheets is not only often necessary, but requires the use of innovative chemistry to achieve high selectivity. Today, increasingly stringent demands for the high-purity cobalt and nickel salts required for battery applications in consumer electronics, electric vehicles, and solar applications are again challenging the state of the art. The evolution of cobalt–nickel separations is traced from the basic precipitation technologies employed in 1960s, through commissioning of the first cobalt solvent-extraction plant in South Africa in 1974, to the commercialisation of organophosphinic-acid extractants (which provided a step-change improvement in selectivity) and their eventual widespread use in the 1980s and ’90s. This was followed later by their sulphur analogue, which enabled different possibilities for laterite processing in the new millennium. Separations in chloride media, which take advantage of the different speciation chemistries, and nickel extraction by oximes in ammoniacal systems are also discussed. More recently, chelating and solvent-impregnated resins have added further dimensions to the possibilities for flowsheet design and enabled higher purity products to be attained from both primary and secondary sources. Selected case studies and flowsheets are described.

By T. Moyo

"The oxidative leaching of chalcopyrite in ammoniacal solutions has been evaluated using electro-analytical techniques and controlled bulk leaching studies. The anodic dissolution process has been established to be a sevenelectron transfer process under nitrogen in ammonia–ammonium sulphate solutions and ammonia–ammonium carbonate solutions, which suggests that the sulphur is oxidized to thiosulphate and the copper and iron released as Cu+ and Fe2+ in these systems. The deportment of Fe2+ and S2O3 2- is affected by choice of the ammonium salt used in the leaching process. In the perchlorate salt, only five electrons are transferred, supporting formation of different sulphur species as proposed for the sulphate and carbonate salts. Scanning electron microscopy and energydispersive spectroscopic analysis of the mineral surface after leaching indicate presence of an iron–sulphur surface layer completely free of copper in the sulphate system, an iron-rich surface layer in the perchlorate solutions, and absence of surface layer build-up in carbonate solutions. XRD analysis of a bulk leach residue from leaching in ammoniaammonium sulphate solutions showed the surface layer to be mostly amorphous (90%). The crystalline content (10%) is composed of 95% polymorphs of anhydrous iron oxide hydroxide FeO(OH). Choice of ammonium salt and the hydrodynamic environment of leaching have been shown to influence the presence or absence of the surface product, as well as its nature. IntroductionHydrometallurgical processes for copper extraction provide a viable route to recover the metal from mixed and low-grade ores, as well as overcome the environmental challenges faced by the traditional pyrometallurgical processes. Chalcopyrite is not only the most abundant of the copper sulphides, but also the most stable, making it recalcitrant to hydrometallurgical processes. Hence, hydrometallurgical processing of chalcopyrite continues to be an attractive area of research due to the vaguely understood surface chemistry of the mineral in different aqueous media. Different routes for hydrometallurgical treatment of chalcopyrite can be followed. These include thermal treatment prior to leaching, direct leaching and direct electrochemical leaching (Venkatachalam, 1991). Direct leaching of chalcopyrite can be carried out in various solution systems, as reviewed by Roman and Benner (1973) and Venkatachalam (1991). Ammoniacal solutions are attractive and effective lixiviants that form stable amine complexes with some base metal cations while rejecting iron. Leaching of chalcopyrite in ammoniacal solutions in the presence of an oxidant is possible due to the stabilization of copper (I) and copper(II) by ammonia at elevated pH levels. In oxygenated ammonia solutions, it has been suggested that chalcopyrite dissolves according to Equation [1] (Beckstead and Miller., 1977a):"

Jan 1, 2016

By Karl-Heinz Frohne

This report presents the findings of a study of a portion of the Clover-Rush Run oilfield located in Roane County, W. Va. The study was made to investigate the possibilities of secondary oil recovery in the Big Injun sandstone underlying the William Kaufman lease. Reservoir properties, original reserves, and primary oil recovery are also presented. The investigation is based on a core analysis and related laboratory tests, well records, field production data, and subsurface information from the Kaufman property. A theoretical primary oil recovery of 9.7 percent of original oil in place is predicted for the reservoir. A waterflood performance prediction of a hypothetical pilot area was made by use of a computer. The prediction showed that, based on laboratory oil water relative permeability curves, the water-injection time needed to initiate oil production is excessive and that the stabilized water-injection and corresponding oil-production rates are very low. This precludes waterflooding the reservoir on an economic basis. A prediction for secondary oil recovery by gas injection was attempted but could not be completed because essential reservoir data were not available. In July 1965, the lease operator initiated, and is currently conducting, a gas-injection program, but there had been no increase in oil production up to November 1966.

Jan 1, 1967

By Timothy Barton

The uniaxial compressive strength (UCS) is the most fundamental measurement used in geotechnical rock characterization for mine design. While there are standardized procedures for how to conduct UCS tests, there are no firm guidelines as to when to conduct them. However, it is well known that the strengths of at least some rocks can change during the time between when the core first comes up out of the hole and when it is prepared and tested in the lab. The goal of this NIOSH (National Institute for Occupational Safety and Health) study was to evaluate UCS changes occurring in a broad range of weak coal measure rocks over a one-year time span. The study found the highest moisture contents were measured when the core was fresh, immediately after it was taken from the hole. The specimens then dried rapidly over the next few weeks. Subsequently, sample moisture contents decreased slightly in the winter and increased in the summer in response to the ambient changes in humidity. The measured UCS of the core also changed during the year, apparently in response to changes in the moisture content. The UCS values from the dry, winter months were, on average, 60% higher than the values obtained when the core was fresh, and the summer UCS was approximately 11% lower than the winter UCS. These findings have implications for the use of UCS as an input parameter for both empirical and numerical mine design methods. UCS values of unprotected core tested weeks to months after drilling can be significantly stronger and indicate stronger roof sequences than warranted. In order to obtain the most representative and reliable UCS value, it is necessary to test the core, or wrap and seal it, at the drill site shortly after recovery.

Jan 1, 2008

By Tsuyoshi Honda, Kazuhiro Kaneda, Masayuki Imai, Kazuo Konishi, Kunio Higashinaka

"In recent years, the demand for measures to control liquefaction of existing airport runways and harbor structures has increased. However, from the perspectives of constructability and cost, application of grid-form deep mixing walls to these types of structures requires the formation of wider grid spacing as compared with conventional designs. In this research, we focused on the extent of liquefaction and ground surface settling when grid spacing is made wider than conventional designs. We conducted centrifuge model tests, and confirmed the liquefaction suppression effect when grid-form modifications involving wide grid spacing are adopted under asphalt pavement. The tests were conducted under conditions that included changing the grid spacing and groundwater level. When the groundwater level was high, an increase in water pressure was observed, even within the grid. However, when the groundwater level was low, the increase in water pressure inside the grid was suppressed. We also found that if the generation of water pressure can be suppressed, the amount of settling due to liquefaction can also be controlled.INTRODUCTIONOne construction technique used as a countermeasure to liquefaction is grid-form deep mixing walls. Grid-form deep mixing walls are a construction technique for which improved grid-shaped wall bodies are built into the ground below the surface using a deep mixing method. This construction technique minimizes shear deformation by surrounding liquefied ground with improved wall bodies, thereby preventing liquefaction (Fig.1). With conventional designs, grid-form deep mixing walls determine the grid spacing that can deter liquefaction based on a ratio of the grid spacing L to the improved depth H (ratio = L/H). Ordinarily, designs are implemented with an L/H ratio of 0.8 or less (PWRI, 1999).In recent years, a demand for measures to control liquefaction of existing airport pavement and harbor structures has increased. However, when liquefaction countermeasures are implemented at these types of facilities and structures, the construction work must be implemented while the facilities and structures remain in service. Therefore, temporal and spatial constraints must be considered. In addition, unlike conventional liquefaction countermeasures, performance requirements are such that, even if some degree of liquefaction is allowed, the performance is acceptable as long as the amount of settlement is within a predetermined value. Therefore, if grid-form deep mixing walls are applied to these structures, grid spacing that is wider than conventional standards is desired."

Jan 1, 2015

By Seppo] [Kreula

Outokumpu Oy has acquired considerable experience with on-stream X-ray fluorescence analyzers and with computer control of flotation processes over several years. It became evident at the outset of this work that a reliable and accurate on-stream analyzer was more than a collection of different pieces of hardware linked together. Extensive work was done to develop an integral analyzer system, beginning with process samples through the spectrometer to report typewriters, recorders and the control computer. To date, over ten Courier-300 analyzer systems based on this development have been installed world-wide, several of which provide the key information for successful computer control systems. Computer control of flotation processes has been under development at the Pyhäsalmi concentrator since 1968. Two different control strategies have been implemented. The copper flotation is controlled by means of a mathematical model and economic criteria, whereas the "evolutionary operation principle" is applied to the zinc flotation. The computer control system installed at' the Vuonos-mine has been developed according to the same guidelines. In order to consolidate this wide experience, a flotation computer control system, Proscon-100, was developed by Outokumpu Oy, and the first system was installed at Kotalahti in 1972. In addition to the technological experience, enough information has also been gathered to illustrate the economical, benefits accruing through the use of these advanced tools of automation.

Jan 1, 1973

By Corliss R. Kinney

Since the first atomic bomb exploded over Japan, a great deal of speculation has been published about the use of atomic energy instead of coal for the production of power. Atomic energy, in time, may displace coal for this purpose, but atomic energy will not displace coal in supplying chemical raw materials to the rapidly expanding carbon-chemicals market. Modern civilization demands large quantities of carbon compounds and the logical source of many of these is coal. Consequently, many progressive operators are considering the possibilities of the utilization of coal as a chemical raw material as never before. Furthermore, the demand for clean, smokeless, and ashless fuels will continue to increase and the only way to handle coal under those conditions is to take it apart, just as crude petroleum is taken apart. One can readily imagine where the petroleum industry would be now if it had insisted on selling customers only crude oil, perhaps emulsified with a little salt water to correspond to the moisture and mineral matter in raw coal. The time seems to be coming at an accelerated Dace when mine operators will find that competing for a highly selective fuel market by producing a larger tonnage at smaller cost will be less profitable than to increase the value of a smaller tonnage many fold by producing something more valuable to industry and civilization than raw coal. For example, about 750,000 tons of carbon black selling for $50 to $60 per ton was produced in the United States in 1945. This tonnage is insignificant compared with the total production of coal in the United States, but a very tidy tonnage, together with the coal necessary to operate the process, for any mine operator fortunate enough to obtain a method of producing a better carbon black from coal. From the point of view of tonnage, the manufacture of coke of various kinds and its by-products is at present the most important source of carbon chemicals from coal. Nearly 20 per cent of the coal mined in this country is used for this purpose. A large proportion of the coke is used for the production of iron and steel, but even in this operation a considerable part of the coke is used for a chemical purpose; that is, the reduction of the ore to metallic iron. In addition, large quantities of coke are used in manufacturing many important products that find their way into the market. Possibilities of Acetylene One of the important chemicals manufactured from coke is calcium carbide, from which many products are made. One of these is acetylene. This hydrocarbon can also be manufactured from natural gas or from waste oil-refinery gas and these industries will probably offer competition for the manufacture of acetylene. Coke-oven gas can be used for making acetylene and should receive consideration

Jan 1, 1947

By E. S. Greiner

STUDY of the plasticity of germanium or other semiconductor crystals affords unusual opportunities to extend our knowledge of deformation mechanisms. Crystals are available having extraordinary perfection and very high purity. They deform by slip on the systems {111} <110>,1-3 as do crystals of the simple face-centered-cubic structure. Dislocations generated in them during slip are easily revealed in the form of etch pits on either (111) or (100) surfaces.4,5 This fact alone makes possible more detailed studies of mechanisms than is usually the case with metals but, even further, the effect of deformation on their electrical conductivity is very large compared with metals. This comes about not only because the mobility of the charge carriers is reduced, as in deformed metals, but also because the number of these carriers is greatly altered. This latter effect seems closely related to the formation of both line and point imperfections during deformation and thus provides a needed tool for the study of the kinds and distributions of these imperfections. Other investigators have deformed germanium at elevated temperatures by bending,1, 6-8 compres-sion,6, 0,10 tension,2,3,6,11,12 torsion,23 and indentation." Wang and Alexander" have also reported successful indentation at room temperature. Dislocation etch pits consequent to deformation have been observed and studied.7,8,10,18,14,20 The experiments to be de- scribed here include principally the compression and the subsequent annealing of germanium with concomitant studies of etch pits, microstructures, and electrical properties. Both single crystals and heavily twinned specimens were used. Some indentation studies are included. Experimental Methods Plastic compression was effected in the apparatus shown schematically in Fig. 1. It consists of two tantalum platens contained in a helium atmosphere and so arranged that pressure can be applied by a hydraulic press. The specimen between the platens is heated by the surrounding furnace. The specimen is usually a small crystal cube about 0.30 in. on an edge. A control specimen is always inserted so, that it is subject to the same thermal cycle as the one being deformed. This serves to detect any impurity contamination that might accompany the thermal treatment. For high temperature work, where such impurity contamination often occurs, the specimens were first plated with gold whenever subsequent electrical properties were to be determined. This method" is effective in preventing significant contamination of germanium up to temperatures at least as high as 750°C, as evidenced by the constancy of the electrical conductivities of control specimens subjected to the same heat treatments. The total range of temperature used for deformation was from 375°C, the lowest at which significant flow was observed, up to 900°C. Microscopic examination was made after mechanical and chemical polishing and etching. Dislocation pits were revealed with CP-4 etchant by the tech-

Jan 1, 1958

By F. Sachanidis

The lignite surface mines of Ptolemais basin operate according to special environmental terms regarding the concentrations of heavy metals and trace elements in water discharges. Based ?n the results of lab analyses and in-situ measurements conducted so far it is concluded that the concentrations of heavy - toxic metals and other trace elements are low or negligible. The deviations from the upper concentration limits specified by laws and regulations are rare and non-systematic both on their spatial or temporal distribution. The same results prove also the relation between water quality and type and nature of the sediments forming the Ptolemais basin and the carbonated and metamorphic rocks forming the surrounding mountain areas.

Jan 1, 2006

By Corliss R. Kinney

Since the first atomic bomb exploded over Japan, a great deal of speculation has been published about the use of atomic energy instead of coal for the production of power. Atomic energy, in time, may displace coal for this purpose, but atomic energy will not displace coal in supplying chemical raw materials to the rapidly expanding carbon-chemicals market. Modern civilization demands large quantities of carbon compounds and the logical source of many of these is coal. Consequently, many progressive operators are considering the possibilities of the utilization of coal as a chemical raw material as never before. Furthermore, the demand for clean, smokeless, and ashless fuels will continue to increase and the only way to handle coal under those conditions is to take it apart, just as crude petroleum is taken apart. One can readily imagine where the petroleum industry would be now if it had insisted on selling customers only crude oil, perhaps emulsified with a little salt water to correspond to the moisture and mineral matter in raw coal. The time seems to be coming at an accelerated Dace when mine operators will find that competing for a highly selective fuel market by producing a larger tonnage at smaller cost will be less profitable than to increase the value of a smaller tonnage many fold by producing something more valuable to industry and civilization than raw coal. For example, about 750,000 tons of carbon black selling for $50 to $60 per ton was produced in the United States in 1945. This tonnage is insignificant compared with the total production of coal in the United States, but a very tidy tonnage, together with the coal necessary to operate the process, for any mine operator fortunate enough to obtain a method of producing a better carbon black from coal. From the point of view of tonnage, the manufacture of coke of various kinds and its by-products is at present the most important source of carbon chemicals from coal. Nearly 20 per cent of the coal mined in this country is used for this purpose. A large proportion of the coke is used for the production of iron and steel, but even in this operation a considerable part of the coke is used for a chemical purpose; that is, the reduction of the ore to metallic iron. In addition, large quantities of coke are used in manufacturing many important products that find their way into the market. Possibilities of Acetylene One of the important chemicals manufactured from coke is calcium carbide, from which many products are made. One of these is acetylene. This hydrocarbon can also be manufactured from natural gas or from waste oil-refinery gas and these industries will probably offer competition for the manufacture of acetylene. Coke-oven gas can be used for making acetylene and should receive consideration

Jan 1, 1947

By Yvon H. Poirier

Carbon addition in the oxide pelletizing process is a big concern at the Sidbec-Normines pelletizing plant since 1976. Laboratory pot-grate testing carried out before the initial start-up of the Port-Cartier plant indicated that the nominal pelletizing grate capacity could be increased by fifteen percent with a suitable carbon addition. Also an improved induration cycle offered the possibility of a significant energy reduction within the process with no adverse effect on pellet quality. A one month plant scale program duplicated the lab test results and confirmed the anticipated cost saving by using these techniques. Since March &apos;80, Sidbec-Normines use coke addition as a current operation. This paper reviews briefly earlier laboratory and in-plant test work carried out to investigate the effects of adding carbon materials to the Fire Lake hematite concentrate, and presents operation techniques and plant results of carbon addition in the Port-Cartier pellet plant.

Jan 1, 1982

By R. E. Ogilvie, H. C. Gatos, R. E. Hanneman

The ejj-ect of high pressures on chemical inter-diffusion in the Fe-V system was determined by analyses of concentration vs distance profiles of atmospheric and high-pressure diffusion couples. Diffusion data were obtained as a function of tern -perature and composition. Activation energies, activation volumes, and frequency factors were determined at 1 atm, 20 kbars, and 40 kbars as a function concentration in the a and y phases. The A great deal of research has been carried out in the measurement and understanding of binary chemical inter diffusion in solids. Studies of the effects of high pressure on interdiffusion in binary systems, however, have been virtually nonexistent until the present work. This paper gives a detailed account of the effect of high pressure on interdiffusion and the Kirkendall effect in the Fe-V system. The present data are compared to existing theo- Kirkendall effects were measured at 1 atm and 40 kbars. At 1 atm Dy > DFe at the marker concentration; however, Dv approaches DFe under pressure, and at 40 kbars the values are approximately equal. The high-pressure and atmospheric diffusion data are evaluated on the basis of theoretical models. Chemical analyses of the diffusion -couple profiles were made using an electron microbeam probe. retical treatments of pressure dependence of diffusion which are based upon self-diffusion studies. THEORY The rates of atomic migration in metals and alloys are regulated by the repulsive forces exerted on an atom during its motion from one equilibrium lattice site to another and by the availability of a jump site. Application of high pressure is expected to decrease diffusion rates because it decreases interatomic distances as well as defect concentrations. A number of theoretical treatments have been focused on the problem of calculating self-diffusion coefficients in solids under atmospheric pressure. In general, the vacancy mechanism of diffusion appears to be dominant at high temperatures in most metallic systems. The migration of an atom by this

Jan 1, 1965

By J. W. Littleford

The Roan Antelope Copper Mines Ltd. are situated in the north central part of Northern Rhodesia, at an altitude of 4000 ft. and 13" south of the Equator. The town site (Luanshya) is well situated and enjoys among other things a really temperate climate for 10 months of the year. The two spring and summer months, October and November, while hot and humid, do not bring any great discomforts as compared with many other mining camps. Strictly modern brick homes, with electric lights, purified water, telephone and water-borne sewage, add to the comfort of the employees. A rainfall of approximately 60 in. per year furnishes ample water for both industrial and domestic purposes. The rainy season generally begins in October and lasts through until March. As much as 3 to 4 in. is recorded in 24 hr., but this offers no difficulties because the runoff is very rapid. The property is connected by a 24-mile branch line from Ndola with the main line of the Beira-Mashonaland and Rhodesia Railways Ltd. Practically all supplies from overseas are transported over this line from Beira, 1743 miles distant on the east coast in Portuguese East Africa. The mine output also leaves Africa from this port. Passenger service is principally via Cape Town or Durban, a distance of about 2100 miles to either port. The Imperial Airways maintain a service from Cape Town to Croydon, taking 9 days for the trip. Connections can be made with this service at Broken Hill, 150 miles south of Luanshya, by either rail or automobile. Thus, after several days of travel through virgin bush, a visitor arrives at a typically modern town site in the heart of Africa. Every development in mining, milling and smelting practice is used to advantage. Plan of Mill The practice in the three principal phases of the production of copper from the ores of this company have been published from time to time. Milling practice, however, is continually changing and what may be

Jan 1, 1935

By C. R. Austin

Tan investigation described in this paper deals with the development of high-temperature alloys of the Konel series over a considerable period of time at the Research Laboratories of the Westinghouse Electric and Manufacturing Co. The word "Konel" has been coined to designate a class of alloys which are essentially nickel-cobalt-iron with other elements added, usually in small quantities. Most of these alloys contain titanium, usually about 2.5 per cent. The main consideration related to strength at high temperatures but the thermionic characteristics of the alloys was also of considerable importance. It is, however, with the mechanical properties at elevated temperatures that we are herein concerned. Much attention has also been devoted to their age-hardening characteristics. There is little need to stress the utilitarian aspect of this subject, as it has been discussed frequently. Alloys exhibiting superior properties at normal or elevated temperatures rapidly find many suitable applications. There may be some question, however, as to what constitutes a "superior alloy, " or an alloy that may have good service possibilities at high temperatures. The problem is complex and various means have been employed to predict the useful life that may be expected of a material. In recent years the "creep limit" has been used as the best means of evaluation. Such tests necessarily are prolonged and hence collection of data is very slow. In a general survey of many alloys therefore the creep test is not desirable and recourse must be had to much shorter time tests in order more rapidly to select alloys which appear to show promise. For this reason the present survey has been made using the high-temperature tensile test and a bend test developed by Howard Scott.1 In the tensile test the conditions have been standardized for all tests, so that values obtained are at least comparable, one alloy with another, although the absolute values recorded merely indicate the mechanical properties at the given temperature under a definite rate of loading.

Jan 1, 1931