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By Dirk van Zyl

The paper describes the construction of a clay pad in Southern California. The pad consisted of a mixture of in situ soil and imported clay products. The paper summarizes design considerations. Laboratory permeability tests performed on samples removed from the pad formed part of the quality control requirement of the State of California Water Quality Control Board. The paper presents statistical analysis of the data (about 70 permeability tests in total) and their significance in controlling seepage losses. The results obtained from an investigation of the first pad-area after completion of the leach cycle are presented and discussed. Results from visual observations and laboratory tests are presented.

Jan 1, 1984

By H. H. Wade, N. F. Schulz

The large quantities of iron-bearing materials, including taconite, semi-taconite," and other low-grade ferruginous materials occurring in Minnesota and elsewhere, constitute an important potential source of iron. Satisfactory grade and recovery of iron ore concentrate cannot ordinarily be obtained from these ferruginous materials by simple methods of beneficiation. Iron is distinctive in that the free metal and two of its oxides [magnetite (Fe,O,) and maghemite (gamma-Fe,O,) ] are strongly ferromagnetic. The successful magnetic separation of natural magnetite from taconite has already been established on a commercial scale. The iron in semi-taconite, how- ever, occurs largely as goethite (Fe,Os.H,O) and hematite (Fe90,) which do not respond to ordinary magnetic separation methods. Magnetic roasting converts these iron oxides to magnetite, which can, after liberation, be magnetically concentrated.

Jan 11, 1960

By Karl Eilers

This process, invented by Messrs. Hanisch and Schroder, of Rosdzin, was patented in 1883. It has attracted considerable attention in Germany, as a very neat and simple method of extracting sulphurous acid from the gases produced by roasting, and of condensing this acid so as to obtain it in the very compact anhydrous liquid form. The special importance which such a process may have at this time in the United States is suggested by the growing inconvenience, amounting to distress, experienced in such localities as Butte, Mont., where the sulphurous gases from large roast-plants have proved not only fatal to vegetation but injurious to human health. It is reported that the authorities of Butte are earnestly considering the enterprise of removing, if practicable, the dense and suffocating cloud which now hangs over that city, and of which sulphurous acid undoubtedly forms the greater and most oppressive, if not the most poisonous, part. May it not be that the solution of this problem is furnished by a

Jan 1, 1892

By M. J. deBastiani, John Kostuik

The Denison orebody, located on the north limb of a syncline, rests at depths of 800 ft in the northern end of the property to 3000 ft at the southern end, and has a composite dip of 19º, varying locally from 0º to 45º. It is composed essentially of two pyritized conglomerate beds separated by a varying thickness of quartzite. The thickness of the upper conglomerate reef of the main ore zone varies from 2 to 15 ft while the lower reef is from 2 to 12 ft. Mining, whether carried out over the entire section of the reefs and quartzite or by selective mining of the reefs, is accomplished by room and pillar methods, with an initial 67% extraction on the advance towards the property boundaries. The underground ore handling requirement in such an orebody has become one of the most challenging problems in mining.

Jan 8, 1966

By A. D. S. Gillies

One of the most difficult places to ventilate in any mine is the working face area. With an everchanging configuration, continual modification and extension to the ventilation system is necessary to maintain an adequate supply of fresh air and to avoid mixing and recirculation in the face area. In coal mines, methane emissions and high dust levels as coal is broken and removed from the face area can produce unhealthy and dangerous conditions if ventilation is not adequately monitored.

Jan 1, 1982

By Michael W. Roper

McDermitt mine is located southwest of McDermitt, Nev., ½ mile north of the old Cordero mine. Geologic structure of the district is that of a Miocene age collapse-type caldera in a region of Basin and Range normal faulting. The McDermitt ore body possess a tabular, gently dipping configuration within 150 ft of the surface over an area 2200 x 2500 ft. Indicated ore reserves are 3 million tons at 10 lb Hg per ton. The ore zone averages 20 ft in thickness and consists of cinnabar (HgS) and corderoite (Hg3S2Cl2) deposited parallel to bedding in argillized Miocene age tuffaceous lacustrine sediments. The ore body is localized above a silicious sinter-silicified lake-bed breccia. This "opalite" breccia unit possesses a gently dipping, apronlike configuration, striking northeast, parallel the trend of the Cordero deposit, and thinning to the north and northwest.

Jan 1, 1977

By H. J. Beattie

R. L. Stegman and M. R. Achter (U.S. Naval Research Laboratory)—In a study of the surface structures developed in the fatigue of nickel at low strains as a function of temperature, we have obtained similar results.3 As our apparatus permits fatigue tests to be conducted in vacuo, there was no masking of the surface at high temperatures by oxidation so that the structures there could be observed directly. The relatively few broad slip bands observed at room temperature gave way at 300°C to a large number of uniformly distributed and narrower slip bands. At 550°C deformation began to concentrate around the grain boundaries and progressively increased up to 800°C. In addition fatigue strength was observed initially to increase with increasing temperature up to about 600°C due to the effectively increased ductility caused by the dispersal of fatigue damage. The fatigue strength then decreased at higher temperatures as grain boundary cracking dominates. Maria Ronay, W. H. Reimann, and W. A. Wood (authors' reply)— The authors are pleased to note that R. L. Stegman and M. R. Achter reach similar conclusions from their study of surface slip on nickel. However, they would emphasize that their own conclusions are based on what is shown by study of specimens that have been sectioned and that this study also shows that surface slip is not necessarily representative of what happens below the surface.

Jan 1, 1965

By William B. Potter

We have come together on this occasion, as so often before the members of the Institute have met in friendly council, to hear and discuss whatever investigation, observation, and experience during the past months may have developed of value or interest to the many departments of knowledge and practice represented in this association. The member, possessed of the true scientific spirit which this Institute is especially intended to foster, brings here the results of his experience and study unrestrained by fear of giving undue advantage to competitor or rival. He appreciates, moreover, the responsibilities of membership and his duty to the cause, and how much is to be gained by himself from the keen but friendly criticism of his fellow-workers and even by the suggestions that may come of shrewd question or chance remark from those who labor in other but related fields.

Jan 1, 1889

By Robert C. Edmiston

The measurement of temperatures in exploratory drill holes yields information on regional and local geothermal gradients and mean surface temperatures. This data may be beneficial to the mining geologist interested in the occurrence and oxidation of metallic sulfide minerals or to the mining engineer interested in subsurface temperatures or water movement. Additionally, the estimation of mean surface temperatures by the projection of thermal gradients to the ground surface provides data on which to evaluate infrared imagery as an exploration tool. Temperature measurements in 30 diamond drill holes in the Silver Bell mining district of Arizona show that a regional geothermal gradient of 2.45°C per 100 m increases to 3.03°C per 100 m near the ground surface. It is also found that an anomaly in the mean annual surface temperature of 0.5°C is associated with the shallow occurrence of disseminated sulfides. Changes in the geothermal gradient due to topography, water circulation, and formation changes also occur.

Jan 1, 1976

By R. L. Stegman, M. R. Achter

R. L. Stegman and M. R. Achter (U.S. Naval Research Laboratory)—In a study of the surface structures developed in the fatigue of nickel at low strains as a function of temperature, we have obtained similar results.3 As our apparatus permits fatigue tests to be conducted in vacuo, there was no masking of the surface at high temperatures by oxidation so that the structures there could be observed directly. The relatively few broad slip bands observed at room temperature gave way at 300°C to a large number of uniformly distributed and narrower slip bands. At 550°C deformation began to concentrate around the grain boundaries and progressively increased up to 800°C. In addition fatigue strength was observed initially to increase with increasing temperature up to about 600°C due to the effectively increased ductility caused by the dispersal of fatigue damage. The fatigue strength then decreased at higher temperatures as grain boundary cracking dominates. Maria Ronay, W. H. Reimann, and W. A. Wood (authors' reply)— The authors are pleased to note that R. L. Stegman and M. R. Achter reach similar conclusions from their study of surface slip on nickel. However, they would emphasize that their own conclusions are based on what is shown by study of specimens that have been sectioned and that this study also shows that surface slip is not necessarily representative of what happens below the surface.

Jan 1, 1965

By Heinrich Siemes, Christa Hennig-Michaeli

The effect of temperature and orientation on the plastic behaviour of an impure titaniferous magnetite from Palabora (South Africa) has been investigated. Prismatic specimens were axially compressed along [001], [110] and [111]. The strain rate was about 3.10-6 s-1. Trace analyses of glide lines revealed a plastic anisotropy due to glide on several non-equivalent crystallographic planes. At 200 °C {111}<112> twinning, {111}<110> slip and {100}<011> slip have been operative. At 400 °C {111}<110> slip and {100}<011> slip are primary glide modes. {110}<110> slip seems to be a secondary glide mode in the [001] specimens at 400 °C. {III}<112> twin glide generates isolated sharp lamellae. {111}<110> slip produces smooth surface striae. {100}<011> slip is characterized by coarse and partially wavy slip bands. {I10}<110> slip displays faint remarkably equidistant glide lines. The critical resolved shear stresses (CRSS) decrease with rise of temperature. The CRSS ratio of slip on [100) to slip on {lll} increases from 1.1 at 200 °C to 1.4 at 400 °C giving rise to a distinct flow anisotropy of the magnetite at 400 °C.

Jan 1, 1982

By Sylvia Whitehead, G. M. Schwartz, J. N. Gundersen

Sylvia Whitehead (Petrologist, The Broken Hill Propriety Co. Ltd., Melbourne, Australia) — Examination of thin sections of jaspilites from numerous banded iron formations in Australia has revealed no evidence to suggest that silicate minerals have formed by reaction between magnetite and silica. Textural relations indicate that part of the magnetite crystallized very early in the history of the rocks, probably during diagenesis, and remained stable under conditions of metamorphism altering only to hematite or limonite under conditions of oxidation and weathering. Many jaspilites also contain later magnetite which is almost certainly of metamorphic origin. Wherever magnetite is present in quartz rich bands containing little or no silicate or carbonate, it is very fine grained and occurs generally as isolated, well formed octahedral crystals or as small crystalline aggregates. These show no evidence of corrosion or reaction with the quartz even in rocks where adjacent bands contain silicate minerals of moderate to high metamorphic grade. Concerning the silicate minerals, it is reasonably certain that bands of very fine grained stilpnomelane

Jan 1, 1963

By Joseph Pogue

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

Jan 3, 1924

By James F. Lewis

The hematite iron ore mines east of the Hudson River are confined to a strip of country ten to fifteen miles wide, commencing on the south, near Fishkill, running northeast through Dutchess County, and striking the southeast corner of Columbia County, extending into Litchfield County, Conn., known there as the Salisbury mines, cropping out again at and near West Stockbridge, Lanesboro, and Cheshire, Mass., also in Bennington County, Vermont. The ores are found in beds or deposits and in veins, with a limestone ledge on one side and slate on the other, from six to thirty feet from the surface. Portions of it are quite solid, called rock ore, but

By R. J. Lipp, I. Iwasaki, R. H. Heerema

The presence of calcium ion in iron ore pulps that are upgraded by selective desliming can result in indiscriminate flocculation of both iron oxide and siliceous gangue slimes. In order to overcome this adverse effect, deflocculation by three complexing agents, namely ethylenediaminetetzaacetate (EDTA), sodium tripolyphosphate (STPP), and sodium hexametaphosphate (SHMP), was investigated. The precipitates and complexes of these agents with calcium ion were characterized by potentiometric and conductometric titrations, and the surface properties of quartz and goethite were studied in the presence of calcium ion and of the complexing agents by means of streaming potential measurements and flotation tests. The results were then correlated with selective flocculation tests on an artificial mixture of quartz and goethite. EDTA markedly improved the selectivity of flocculation when added in near stoichiometric amounts, whereas STPP was less effective and SHMP was totally ineffective due to strong, indiscriminate dispersion. Remanent calcium polyphosphates on the goethite surface interfered with the adsorption of starch flocculant.

Jan 1, 1983

By T. W. Healy, M. S. Moignard

The use of electrokinetic or zeta-potential phenomena in studies of the properties of mineral sulphides has increased greatly over recent years. This review aims to examine and discuss the body of literature on the subject of electrokinetic properties of sulphides in a comprehensive and critical manner. Although the review covers the period from 1925 to 1975, it is only in the past ten years that researchers have been fully aware of the implications and problems of chemical reactions, notably oxidation and precipitation reactions, on the surface properties of sulphide minerals. These papers are discussed in more detail than the earlier publications. A table containing a list of determinations of iso-electric- points and points-of-zero-charge of mineral sulphides, and the methods employed in obtaining these results, is presented.

Jan 1, 1976

By Abbas Ali Daneshy

A study of the mechanics of hydraulic fracturing shows the fracture initiation pressure to be a function of the in-situ principal stresses, the formation and fluid properties, and how the wellbore has been completed. The orientation of the hydraulic fracture is perpendicular to the least in-situ principal stress. The geometry of the induced fracture depends on the treatment fluid properties, the injection rate and volume, fluid leak-off and formation properties.

Jan 1, 1974

By H. A. Schwartz

By analyzing cementite separated electrolytically from white cast iron of known composition and history, the distribution of silicon between austenite and cementite during and after freezing has been followed. The results constitute a contribution to our knowledge of equilibria in the ternary (metastable) system iron-carbon-silicon. Incidental information was obtained, also, with respect to the distribution of manganese, silicon, and phosphorus, when only relatively small amounts of each are present. The major conclusion of the paper is that during solidification, equilibrium is attained when the silicon is all rejected to the liquid phase, permitting silicon-free austenite to separate. OF THE outstanding investigators of the system iron-carbon-silicon, Gontermann,1 Charpy and Cornu-Thenard,2 and Honda,3 only the first touched on the chemical composition of the solid and liquid phases in equilibrium with one another. He concluded that his data did not permit a decision as to which of an indefinitely large number of pairs of compositions of liquid and solid would be found in any given case. If through the three dimensional equilibrium diagram of the iron-carbon-silicon system an isothermal plane is passed in the region of partial solidification, two lines of intersection with the liquidus and solidus, respectively, are obtained, also a point marking the alloys&apos; composition. If, in this, plane, a straight line is drawn through the point, and intersecting both the liquidus and solidus isothermals, the two intersections mark a liquid and a solid alloy that may be chemically in equilibrium at the chosen temperature. From thermal data alone, Gontermann could not assign any particular direction to the line and, hence, could not determine which pair of conjugate points to choose.

Jan 7, 1924

By Walter R. Hibbard

Whether we have occasion to think of it or not, an adequate and economic supply of energy fuels is vital to each of us. It is interesting to look ahead at the way in which fuels from supplementary sources will begin to enter into the energy mix to help meet the long-term national energy needs. From 1947 to 1965, the average annual rate of growth of energy consumption was 2.7%, with total energy demand in 1965 being equivalent to 54 quadrillion Btu&apos;s. During this short period of 18 years, the cumulative output of coal in the U.S. was 9.6 billion tons; natural gas, 193.5 trillion cu ft; and crude oil, 45.9 billion bbl. During the next decade and a half the nation&apos;s energy requirements are expected to grow at an average rate of 3.3% yearly, with consumption of energy expected to reach an annual rate of about 88 quadrillion Btu&apos;s by 1980, or 63% over the 1965 level.

Jan 12, 1967

By John Chipman, Donald W. Murphy

RECENT developments in iron alloys containing nitrogen have indicated that this element may exert a considerable influence on the properties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Zurich,1 Sieverts,2 Martin,3 and Iwasé4 and, the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss5 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935