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By AIME AIME

PRODUCTION of nickel in Cuba, a new source of this metal, has been started by the Nicaro Nickel Co., subsidiary of the Freeport Sulphur Co. Construction of the Nicaro plant in Oriente Province, Cuba, and of a refinery at Wilmington, Del., has been "substantially completed," according to Langbourne M. Williams, Jr., president. The initial rate of output is less than capacity operation, which will be reached when "the customary problems incident to the commencement of full- scale production are eliminated." The plant in Cuba for the treatment of the extensive nickeliferous ores of that region, and the refinery, were built by Nicaro for the account of the Defense Plant Corp. construction has been under way for eighteen months. The plants, when operating at capacity, are expected to increase America's sup-

Jan 1, 1944

By J. M. Cabal, M. Chica Olmo, J. P. Laille

One of the main goals of a simulation of a coal deposit mining is to predict a series of parameters considered by the miner to be useful, e.g. ash content, sulphur content, seam thickness etc). The idea is to simulate different ways of mining a multi-seam brown coal deposit (the Mine Puentes de Garcia Rodriguez deposit, ENDESA, Spain ), which is exploited by several bucket-wheel-excavators (BWE) . Two mining models are used: a geostatistical model which provides a numerical way of re- presenting the three-dimensional ore-body, then a deterministic model, consisting of simulating the technical aspects of the mining. The main purpose of this simulation is to show how the mining operations can be reproduced using these two techniques.

Jan 1, 1983

By G. W. Donaldson

Theoretical and engineering aspects of slimes-dam construction by G. W. DONALDSON, M.Sc. (Eng.)(U.C.T.), D.I.C. (Visitor) Tile paper reviews the recommendations made in 1959-60 as a result of research into slimes-dam construction and finds that these recommendations are still valid. The requirements for pollution control, vegetating, in situ leaching, and future development of slimes dams as building areas are considered as they affect the engineering aspects of slimes-dam construction, and it is found that these requirements can be met without any major changes to current recommended slimes-dam construction practice.

Jan 12, 1973

By A. D. Davis, D. J. Dixon, J. L. Sorenson, C. J. Webb, S. Dawadi

Limestone-based material appears to be an effective arsenic removal process that has great potential for source reduction in drinking water. Limestone-based material offers several benefits to the drinking water community: 1) reasonable removal efficiency as compared to material cost, 2) broad geographic and water system applicability, 3) compatibility with other water treatment processes, 4) ease of technical use, and 5) low-cost disposal in ordinary landfills. Batch and column experiments have evaluated the removal efficiency of several limestone types. Additives and material alteration have increased the removal efficiency. Granulation of powdered limestone as a filter media currently is being investigated.

Jan 1, 2006

By S. Gallagher, A. Mayton, R. Merkel

The prolonged exposure of equipment operators to shock and whole-body vibration (WBV) IS linked to cumulative back, neck, and abdominal disorders. In low-coal mines, space restrictions make seat suspensions difficult to use in isolating operators from shock and WBV. Researchers at NIOSH, Pittsburgh Research Laboratory, are responding to these issues by investigating viscoelastic foams. For the full-load case. an ergonomic seat with viscoelastic foams isolated the shuttle car operator from shock at 15 Hz. Researchers used results from additional foam testing with an analytical model to identify viscoelastic foams that provide shock isolation at a frequency below 5 Hz.

By Floyd JM

Conventional smelting reactor systems were designed to recover only one main element from their feedstocks. They did not possess sufficient flexibility to allow optimisation of co-production of multiple values from a complex feed.New reactors such as Sirosmelt and Top Blown Rotary Converters are providing new possibilities for making separation between components and this is of great significance for the complex feeds which are becoming prevalent in the metal extraction industry.Process routes using chemical procedures which take advantage of the flexibility of these reactors will be discussed in relation to a number of possible feedstocks.

Jan 1, 1985

By E. P. Klier, V. Weiss

IN studies of the X-ray diffraction line geometry of iron with chromium radiation using techniques aimed at minimizing the background intensity, Kp and Ka emission satellites* were resolved with three techniques. These satellite lines are present with sufficient intensity to lead potentially to erroneous structure analysis, if not properly interpreted. The techniques used were: 1) film technique with un-filtered radiation and polycrystalline specimen, 2) film technique with unfiltered radiation and single crystal, and 3) counter technique with unfiltered radiation and single crystal. An example of results obtained with technique 1 is given in Fig. 1.

Jan 1, 1958

By Gerald M. Friedman

CONVENTIONAL usage defines emery as a natural aggregate of corundum and magnetite. Because emery bodies contain abundant spinel two types are recognized, spinel-bearing and spinel- free. Watson and Steiger1 introduced the name spinellite for emery in which spinel is a major constituuent, but this term has not been generally adopted. Spinel emery grades locally into spinel magnetite rocks with or without accessory corundum. Even this variety has been used commercially in the past. The term emery therefore applies to natural aggregates composed of corundum and magnetite; corundum, magnetite, and spinel; and spinel and magnetite.

Jan 7, 1957

By Tom C. Palanglo, Norbert Maerz

Control of crushing and grinding circuits ideally requires continuous particle size measurements on both in- and outgoing streams. Until recently, size distributions could only be obtained by screening methods, which were neither cost effective, frequent enough, nor timely. Input streams are often composed of large fragments, making screening prohibitive. Optical image processing systems, such as the WipFrag System, have been developed to the point that they are an extremely valuable tool to characterize, control, and fine-tune the comminution process. Although accuracy is less than that of screening, measurements are precise enough to detect relatively small changes in size distributions.

Jan 1, 2000

By S. K. Nicol, A. R. Swanson, J. C. Day

Addition of oil to a suspension of hydrophobic coal particles can influence its dewatering characteristics. An agglomeration process occurs in which coal particles are held together by negative capillary pressure at particle/oil/water contacts. Consequently, the units round which flow can occur are enlarged and this improves dewatering parameters such as drainage rate, solids recovery, and equilibrium moisture content. This paper discusses processes which attempt to use this principle, in terms of metallurgical and economic efficiency. The discussion is augmented by results of recent experiments on the effect of oil addition to centrifuges and vacuum filters.

Jan 1, 1980

By Bern Klein, Richard W. Lawrence, Scott Frostad

Laboratory and field scale kinetic testing was conducted to evaluate scaling up of laboratory data. Two 20- tonne (field) cells were monitored for internal temperature, pH, conductivity, volume and rate of flow, and water quality. On a surface are. basis, results showed sulfide oxidation rates obtained using 50-kg cells are more sensitive to changes in aeration than those from 1-kg cells. Correcting the laboratory oxidation rates for field temperatures with a pH 7 activation energy, which is in the field drainage pH range, returned oxidation rates an order of magnitude lower than the field cell rates.

Jan 1, 2000

By Albert Sauveur

THE following experiments were conducted in order to study the influence of the rate of cooling through and below solidification on the dendritic structure (macrostructure) and microstructure of some hypoeutectoid steel. The steel selected was of commercial grade and had the following composition: C, 0.40 per cent.; Mn, 0.85; Si, 0.70; P, 0.099; S, 0.043. After melting in vacuum in an Arsem furnace, the various samples were allowed to solidify and to cool to room temperature as indicated in Fig. 1. Samples were thus obtained representing all possible combinations of slow and fast cooling through the various ranges of temperatures indicated, namely: (1), zone of solidification or primary crystallization, (2) zone of granulation, and (3) zone of secondary crystallization. The location of the different temperature zones in the iron-carbon equilibrium diagram is shown in Fig. 2. The authors adopted. Belaiew's notations. The designations of the various samples readily indicate their treatment, as will be apparent from Table 1.

Jan 1, 1930

By William L. Fink, Dana W. Smith

Many investigators have attempted to determine the true nature of the internal changes taking place during aging. Merica, Waltenberg and Scottlt were the first to propose a theory of age-hardening. They attributed the age-hardening of duralumin to the precipitation of minute particles of the compound CuA12. Later Zay Jeffries and R. S. Archer2 augmented the above theory by suggesting that the small CuAl2 particles acted as "keys" causing "slip interference." Many other investigators3 have devoted much time to the mechanism of age-hardening, some corroborating the "precipitation" and "slip interference" theory, others coming to different conclusions because of effects that to them seemed unexplainable by the early theories; e.g., the increase of electrical resistance upon aging, the fact that no change in lattice parameter could be detected during the early stages of aging even at elevated temperatures, and the fact that the density did not change as would be predicted. In 1932, Merica revised4 his earlier precipitation theory to take care of these presumably anomalous effects. This revised theory, the "knot" theory, assumes that substantial age-hardening occurs before actual precipitation of solute as discrete particles. The assumed mechanism is one of diffusion of solute atoms into groups forming distorted regions which act as "hard" spots and cause slip interference. These "knots" are assumed to have approximately the same lattice arrangement as the solvent. The anomalous behavior of lattice parameter, density, and electrical conductivity, require a modification of the simple precipitation-hardening theory, only if it is assumed that the precipitation of minute particles during aging has the same effects on these properties as the formation of large particles under equilibrium conditions. Data obtained by the authors in the study of the aluminum-magnesium system5 indicated that

Jan 1, 1936

By Y. Hirosaki, H. Hamashima, Y. Itoh Kato, S. Tanaka

The emulsion explosives show non- ideal detonation behavior, and its detonation velocity can be controled by selecting the size and adjusting the quantity of voids involved. To establish the technology to control the detonation characteristics of the emulsion explosives, some experiments have been carried out using resin balloons of five different sizes ranged from O.OSmm to 2.42mm in the average diameter. Detonation velocities of the emulsion explosives containing resin balloons of different size and quantity were determined for the charge diameter of 20-50mm. The detonation velocity at infinite charge diameter was compared with calculated ideal detonation velocity. The emulsion explosives containing large (0.5mm or larger) balloons showed big discrepancy between the measured and calculated detonation velocities, and the fraction of ammonium nitrate reacted in the reaction zone was estimated to be significantly low. It was shown that the reaction zone length was proportional to the size of voids involved. The critical charge diameter was determined for the emulsion explosives containing different resin balloons at the various explosive densities. It is large for the emulsion explosives containing large voids, and it was shown that the critical diameter is proportional to the distance between the void surfaces, not to the void spacing, the distance between the centers of the voids. The reaction rate of the bulk emulsion matrix seems to be the major factor that affects the critical diameter than the specific surface of voids. Good relationship between the critical diameter and the reaction zone length was observed.

Jan 1, 2000

By U. Schwarz-Schampera, C. Rühlemann, H. -R. Kudrass

Within 2006 BGR will conclude a contract with the UN International Seabed Authority (ISA) for the exploration of polymetallic nodules. The contract covers an area in the Pacific nodule belt between the Clarion and Clipperton fracture zones, that which is about 75.000 km2 in size at water depths between 4200 and 5000 m (see Fig. 1). Up to now, 7 consortia or state parties have acquired similar exploration “licenses” for polymetallic nodules in the central Pacific Ocean and the Indian Ocean. These licenses of the UN authority are required according to the UN convention on the law of the sea (UNCLOS) as the areas of interest are located outside of national EEZs. The “licenses” then reserve exclusive rights to the applicant for a time span of about 15 years.

Aug 24, 2006

By C. Gatlin, M. E. Chenevert

The effects of bedding plane orientation on the elastic constants and the yield strengths of three laminated rocks (one sandstone and two shales) and one isotropic rock (a limestone) were studied. The directional dependence of the elastic properties of these rocks was experimentally evaluated using a triaxial compression cell and auxiliary stress-strain measuring equipment. Symmetry of Poisson's ratios within the bedding plane suggested that horizontal isotropy exists, but the bedding planes do give rise to an appreciable difference between properties in the horizontal and vertical directions. For the three bedded rocks studied, Young's modulus was lower normal to bedding than along bedding. Yield strengths were determined at confining pressures from 0 to 12,000 psi in a triaxial compression cell. The rocks studied showed strength reductions as high as 40 per cent when the test specimen was oriented at 20°-30° to the bedding planes. The mechanical behavior of these rocks suggested that the rock properties of shear strength and/or coefficient of internal friction can vary with direction, depending on the particular rock tested. Tensile strengths were also measured and found to be lowest when failure occurred along bedding. This work shows that bedded formations exhibit sizable directional variations in both their elastic constants and yield strengths. It is suggested that these variations may be accounted for by using the "elastic laminate" model and the "variable coefficients" failure model. INTRODUCTION The nature of rock deformation at elevated pressures has been studied by many workers; papers by Handin,l,2 and Robinson3 illustrate the present state of knowledge. Most investigators have either chosen rocks which were as isotropic as possible (in order to avoid complications of data interpretation and analysis) or they have oriented their samples so that the effects of anisotropies (such as bedding planes) have been avoided. Of the studies performed, few were concerned specifically with mechanical anisotrop-ies. Griggs4 has presented limited data for specimens cut parallel, normal, and 45° to the bedding plane; he relates the strength anisotropy observed to the fabric (bedding) anisotropy. His tests were primarily concerned with large deformations (20 per cent strain); thus, no directional values of the elastic constants were reported. Handin has reported the results of similar experiments. Bott5has discussed rock strength anisotropies due to faults, cleavage, or bedding. He was concerned primari ly with determining the shear stress on such planes and did not mention the effect of friction. Jaeger6 later generalized Bott's work by taking friction into account and presented a limited theory for the failure of rocks having a "single plane of weakness", and also for rocks having a constant coefficient of friction, and a shear strength which varies with bedding plane orientation. Donath and Cohen,7 and Donathg have evaluated rock strengths from shale and slate specimens cut normal and parallel to bedding. A dependence of cohesive strength (7,) on the specimen orientation was also shown. Adler9 has also studied this problem and lists similar results. He assumes that all bedded rocks behave according to Jaeger's single-plane-of-weakness theory. Kalinin and Belorussov10 list results for strength tests parallel and perpendicular to bedding and use this information as a basis for hole deviation analysis. From the literature it is apparent that sedimentary rocks have been tested under widely varying conditions of stress; however, the assumption of isotropy is generally, but not always, made. Since geologic sedimentation often deposits sediments in very definite lavers.,. it seems that more svstema tic attention should be given to the possible effects of this natural bedding. Bedding, as used here, refers to visible regularities of grain size or orientation resulting from depositional processes. The mechanical strength anisotropies, which bedding may present, is not the only anisotronic property to be considered, since the elastic

Jan 1, 1966

By Chai Liyuan

This paper focused on the preparation of porous ceramic pellets for microorganism carriers. A new method for the process was developed using simple gel-casting and bubble-in-water-in-oil type of multiphase double emulsion. The globules, consisting of a foamed sepiolite slurry suspension, were dispersed and consolidated in spherical shape in liquid paraffin as gelation progressed. The green pellets were sintered at 1100°C. The influence of surfactants, extension ratio and impeller revolution rate on the process and characteristics of the pellets was investigated. The pellet size was in the range of 1~4mm and determined directly by impeller revolution rate. The fine cell diameter of porous ceramic was in the range of 100~500m and the micropore diameter was less than 5m. The inner macropores were interconnected and extend to the external surface. It is impossible to analyze a result by SEM micrographs and digital camera.

Jan 1, 2006

By O. Kangal, G. Önal, G. Bulut, A. Gül

The recovery of copper and cobalt from the ancient copper slags, located in Küre-Turkey, is investigated. Fayalitic type of ancient copper slags containing 1.41% Cu, 0.53% Co and 53.16% Fe were subject to the experimental study. Magnetic separation, gravity concentration and flotation test were conducted. The results of magnetic separation and gravity concentration were not satisfactory. However, a concentrate containing 9.57% Cu could be produced with 44.7% recovery by flotation. Copper and cobalt that remained in the flotation tailings was recovered by roasting with sulfuric acid followed by hot water leaching. Complete cobalt dissolution was observed in 1 hour of roasting at 150°C and 3:1 acid/slag ratio, whereas the copper recovery was 83%.

Jan 1, 2004

By Lawrence W. Teufel

An anelastic strain recovery technique is presented as a method of determining the directions and ratio of the maximum and minimum horizontal in-situ stresses from oriented cores from deep wells. Predictions of hydraulic fracture azimuth inferred from principal stress directions determined from both elastic and time-dependent (anelastic) strain relaxation measurements of volcanic tuff are consistent with the observed orientations of hydraulic fractures produced in simulation and mineback experiments, underground at the Nevada Test Site. In addition, anelastic strain recovery measurements on oriented cores of shale and sandstone from well depths of about 1680 meters show consistent relaxation directions of the principal horizontal strains and have enabled a prediction of the principal horizontal stress directions and hydraulic fracture azimuth.

Jan 1, 1982

By Johan M. Versteegen

During the production of silicon carbide a by-product is generated, which contains a mixture of crystalline and amorphous silicon carbide. Utilizing the difference in density, shape and surface properties of the crystalline and amorphous silicon carbide, separation tests were carried out with gravity concentration and flotation equipment. The flotation results of the fine fraction of the silicon carbide mixture were not encouraging. The processing of the coarse fraction of the silicon carbide mixture by jigs resulted in a high grade crystalline SiC concentrate with the desired specifications. The separation was largely influenced by the shape factor. An IHC-jig with a newly designed hydraulic drive was used to carry out the test program.

Jan 1, 1988