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By H Möller

The purpose of this paper is to give an overview of the corrosion behaviour of steel in seawater. It is shown that the corrosion products (oxy-hydroxides and calcareous deposits) that are formed during corrosion in seawater have a significant effect on the corrosion behaviour of steel. The chemical composition of the steel determines how protective the oxy-hydroxide corrosion product is. The composition of the seawater influences the nature of the calcareous deposits. This needs to be considered when artificial solutions are used to simulate the corrosion behaviour of steel in seawater. A 3.5% NaCl solution is used frequently for this purpose, but because no calcareous deposits can be formed in this solution, erroneous results in terms of corrosion rates are obtained. The more complex ASTM D1141 artificial solution can be used to include the effects of ions other than Na+ and Cl- in synthetic seawaters. The importance of these other ions on the formation of calcareous deposits is discussed. Keywords: Steel, corrosion, seawater, calcareous deposits, oxy-hydroxides

Jan 1, 2006

By Joseph H. White, DR. JAMES G. CUMMING

This report presents the results of an investigation of hookworm infection in the deep gold mines of the Mother Lode, California. In this investigation 1,440 miners of the Mother Lode have been examined for hookworm infection; 444 miners were found to be infected; and 91 miners have taken the treatment and have gotten rid of the infection. ·Within a short time after this preliminary examination, an industrial strike started, which gradually scattered the miners and made it difficult to institute the treatment of many of those who had been found infected. ·With the completion, however, of the State survey all these will eventually be identified and treated. In 1906 Dr. F. F. Sprague, of Jackson, Cal., and formerly of the Philippine Islands, recognized the prevalence of hookworm infection in the gold mines of California. He treated many cases of the infection and brought the prevalence of the disease to the attention of his colleagues. Following closely this pioneer work of Dr. Sprague was that of Dr. E. E. Endicott, health officer of Amador County. In 1911 Dr. Endicott a related his experience in a paper before the American Medical Association. In 1909, Dr. Herbert Gunn, under the auspices of the California State Board of Health, made an investigation to determine the prevalence of the disease among miners. b He reported on the blood and stool examinations of groups of men from three large mines in Amador County. The high eosmophilia verified by stool examinations in many of the cases, and the demonstration of larvae in soil from the workings led Dr. Gunn to the following conclusions: 1. Hookworm disease is endemic in certain mines of California. 2. From 50 to 80 per cent of those working in these mines are infected. 3. The infection undoubtedly is present in practically all the gold mines of California and in those of Nevada just over the border. vYhen it was definitely determined by the California State Board of Health to make an investigation, in cooperation with the Industrial Accident Commission of the State of California and the Federal Bureau of Mines, as to the prevalence of hookworm infection among the miners of California, the following procedure was planned: (1) To encourage the superintendents of the various mines to cooperate in the campaign; (2) to diagnose fecal specimens from the miners and determine the percentage of infected miners; (3) to reach an agreement with the superintendents that all infected men must be treated; (4) to make reexaminations of all treated men; (5) to issue "hookworm certificates"; and (6) to eventually reexamine all California miners. A visit to several of the mines on the Mother Lode made it evident that the mine operators would cooperate most cordially in this campaign; in fact, several superintendents had already considered the advisability of such an undertaking.

Jan 1, 1917

By E. S. Chalpin

On 25 August 1971, the U.S. Bureau of Mines contracted with the Aerojet Liquid Rocket Company to perform an engineering research program to be completed on 25 May 1972. The program objective was to evaluate the advantages and disadvantages of the underground use of several power sources including but not limited to a closed cycle diesel, electric cable/motor, rechargeable battery/ motor and exhausting diesel for mine shuttle cars, with emphasis on health and safety. This report, Research in Advanced Power Systems for Mining Health and Safety consists of four (4) main parts: (1) Hazards and Safety Analysis of Mine Power Systems, (2) Evaluation of Closed Cycle Diesel Power System for Mine Applications, (3) Closed Cycle Diesel Power System Consumables Compatibility, and (4) Concluding Remarks and Recommendations. The hazards introduced to a mine by shuttle car power system failure modes were evaluated and reported. A "fault tree" analysis was generated for each power system and the probability of death or injury during an eight (8) hour shift and for a week of operation (105 hours) were estimated. Advantages and disadvantages were also reported for each system studied. Aerojet's assessment, based on a "forced decisions analysis," of the four shuttle car power systems as to their relative health and safety is that the exhausting or open cycle diesel is preferred, followed by the closed cycle diesel, the electric cable/motor and the rechargeable battery/motor. The assessment was based on ten parameters pertinent to the health and safety aspects of shuttle cars. Drawing layouts of two typical mine shuttle cars incorporating closed cycle diesel powerplant concepts are included in this report. The performance parameters established for the two concepts are tabulated. A study was made of the logistics involved in transporting and replenishing the consumables needed to operate a shuttle car equipped with a closed cycle diesel. The closed cycle diesel powerplant consumables -oxygen, potassium hydroxide, and diesel fuel - were analyzed as to their compatibility with materials found normally in a gassy coal mine. Spill tests simulating inadvertent leakage of liquid oxygen in a coal mine were performed. A critical evaluation of existing oxygen sensitivity data and the relationship to the use of oxygen on a shuttle car in a coal mine environment is presented.

Jan 1, 1972

By E. H. Burroughs

HISTORICAL REFERENCES OCCURRENCE-GEOLOGY AND ORIGIN. 4. ARNOLD, RALPH. Conservation of the oil and gas resources of the Americas, Econ. Geol., vol. 11, Apr.-May, 1916, pp. 203-222; June, 1916, pp. 299-326; Proc. 2nd Pan American Sci. Cong., 1915-1916, vol. 3, Conservation of natural resources, pp. 207-237. Shows occurrence of oll, and status and possibilities of oil Industry in each country. Discusses briefly ways in which oll reserves may be conserved. 5. RUTIS, A. A. Petroleum known since remote times. Oil and Gas Jour., vol. 15, Nov. 2, 1916, pp. 33, 37. Gives historical reférences to the use of petroleum from Bible times to its discovery In America. See also Nos. 3, 257, 202, 337, 1843.

Jan 1, 1919

By Anne-Laure Bonnet

Les connaissances acquises au cours des dernières décennies sur les gîtes de métaux de base et précieux intensément métamorphisés (p. ex. Vokes, 1991; Cornell et al., 1992; Zaleski et Peterson, 1995) ont permis d?élaborer des guides d?exploration pour de tels gisements dans les terrains de haut-grade métamorphique (Spry et Scott, 1986; Rubin et al., 1993; Hand et al., 1994; Spry, 2000; Spry et al., 2000). Un transfert de ces connaissances à la cartographie des vastes terrains gneissiques non différentiés de la province de Grenville permet d?affiner l?approche cartographique nécessaire pour reconnaître les systèmes hydrothermaux métamorphisés en terrains vierges et peu diagnostiques puis d?en discriminer les divers halos d?altération (Corriveau et al.,1996, 1997, 1998, 2003; Williamson et al., ce volume). Cette approche prend en compte les « empreintes métamorphiques » observées sur le terrain, telles que les variations des assemblages minéralogiques, du mode et de la composition des minéraux métamorphiques, pour reconnaître des roches présentant une composition inhabituelle caractéristiques de protolites altérés par hydrothermalisme. Ces empreintes citées cidessus sont facilement reconnaissables dans les terrains de haut-grade où la recristallisation induit un grossissement des grains qui permet de déterminer la nature et le mode des minéraux dès les levés de terrain. Cette approche raffine la compréhension des terrains de haut-grade métamorphique et illustre que leur complexité (i.e. polyphasage de la déformation et du métamorphisme) n?est pas forcément une limite à leur exploration. Elle a donc été utilisée systématiquement lors des levés de terrain réalisés dans le cadre d?un projet de l?Initiative géoscientifique ciblée de RNCan. La zone cartographiée se situe le long de la marge sudest du Groupe de Wakeham dans le secteur est de la Province de Grenville. Deux régions ont été plus particulièrement étudiées, celle du lac Musquaro (SNRC 12K10, 11 et 14) et la région côtière comprise entre Kégashka, La Romaine et Baie des Loups (SNRC 12K1, 2, 3 et 7) (fig. 1).

May 1, 2003

By E. P. Dowding, J. Schlocker, C. H. Fuchsman, R. R. Lloyd, Mahan. W. M., O. C. Garst, W. T. Rawles

"INTRODUCTION The United States, although the leading consumer of chromite, depends almost entirely on imports for its supply. For instance, the consumption during. 1941 amounted to 714,645 long tons, whereas the domestic chromite production, although the highest since 1918, was 12,731 long tons or only 1.78 percent of the domestic consumption. 9/ Domestic production was tremendously, accelerated,after 1941 by war demands; however, only a small proportion of this domestic product was of sufficient quality to be substituted for the high-grade imported chromite demanded for metallurgical purpose. Chromite is used largely for making ferrochromium, an alloy containing 60 to 70 percent chromium which is used in making alloy steels. Peacetime specification for ferrochromium required that it should contain 68 to 69 percent chromium. These specification were lowered to between 60 and 63 percent, chromium in 1941 to permit the use of lower-grade ores. The specifications for metallurgical chromite, used for making ferrochromium, were established first by the Metals Reserve Company at 48 percent Cr203 and a Cr. Fe. ratio of 3 : 1 but later were lowered to 45 percent Cr203 and a Cr : Fe ratio of 2.5 : 1. The ratio of chromium to iron in chromite is important, because the contained iron enters the alloy in making ferrochromium and, although an ore may contain the required 45 percent Cr203, it may contain too much to be suitable for ferrochromium production. The principal sources of domestic chromite are California, Oregon, Montana, and Alaska minor, small, and widely scattered deposits in another dozen States. Without exception, these deposits are low-grade, require beneficiation to produce a commercial product, and are not competitive with imported high-grade ore in normal times. Nevertheless, these deposits form strategic reserve, which must be utilized in periods of national emergency. Recognizing this fact; the Bureau of Mines for many years has undertaken investigations to develop methods of utilizing domestic chromite ores. The problem has been approached from three angles: (1) Mechanical methods of concentration; (2) beneficiation by chemical or metal¬lurgical methods; and (3) production of metallic chromium by electrolysis of solutions prepared from ore or concentrate."

Feb 1, 1946

By J. J. S. Sebastian

The process development described in this report was carried out at the Morgantown Station of the U. S. Bureau of Mines in cooperation with West Virginia University. An experimental laboratory-scale pilot unit to gasify coal dust in entrainment was constructed on the Campus of the University in Morgantown. The enormously accelerated demand for liquid and gaseous fuels and utilization of our immense coal resources require that a low-cost process be developed for the gasification of a wide variety of coals. Such a process would be a major factor in lowering the cost of synthetic liquid fuels. None of the proc3sses developed in Germany prior to and during World War II, such as the Winkler process, the H. Koppers dust gasification process, the Wintershall-Schmalfoldt process, etc., meet all the requirements for a low-cost process under American conditions. Nor has any other process designed and experimentally operated at atmospheric pressure during the post-war period in this country appeared to fulfill all of the necessary conditions for a low-cost process.

Jan 1, 1950

The objective of this handbook is to provide the inspector with guidance for recognizing hazards from inhalation contaminants in above ground work areas of underground and surface metal and nonmetal mining and processing facilities and evaluating these hazards by collecting samples or making field determinations and interpreting the analytical results. Portions of the handbook that should prove most useful to the inspectors include a survey check list, rules for determining if sampling is required, list of most frequently encountered contaminants, list of candidate contaminants and their sampling conditions, interpretation of results, and a procedure for a health and safety inspection.

Jan 1, 2011

By Rita D. Sylvester

"This compilation lists and summarizes publications by Bureau authors published in the regular Bureau of Mines series, in scientific, technical, or trade journals, or in other media; those available from the Bureau of Mines are indicated. Patents issued to Bureau personnel are also listed, and instructions are given on how to apply for permission to use them. One of the outstanding features of this Special Publication is an exhausive subject and author index. IntroductionThe Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and present their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries, The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminar's; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue describes reports and articles published during the period January 1, 1970, to December 31, 1974. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;2 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;3 and the 5-year lists of Bureau publications and articles from January I, 1960, to December 31, 1964,4 and from January I, 1965, to December 31, 1969.5 It includes all the material in the four annual lists of Bureau publications and articles from January 1, 1970, to December 31, 1973."

Jan 1, 1975

1. Domestic Production and Use: Twelve companies operated 31 primary aluminum reduction plants, three firms accounting for 66% of production. Washington, Oregon, and Montana accounted for 32% of the total production; Gulf Coast States, 25%; Northern States, 29%; and other Southern States, 14%. Output of primary metal in 1973 was valued at $2.2 billion. About 80% of the secondary recovery was from new aluminum base scrap and 20% was from old scrap. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1972, building accounted for 28%; transportation 19%; electrical, 13%; packaging, 16%; and consumer durab1es, 10%.

Jan 1, 1974

By N. A. White

Whereas the ultimate world supply of energy minerals-defined as fossil fuels and fissile materials - is controlled by geological factors, the actual supply at any particular time is controlled by economic feasibility, technological innovations and /or political decisions. This paper identifies and discusses the principal uncertainties surrounding the international availability of energy minerals from now until the end of the century. A brief comparison is also made between energy and non-energy minerals. Genuine shortage s of energy minerals are now of a very long-term nature, whereas artificial ones may occur at any time and have a serious effect on the world economy due to the dependence of most OECD countries on imports of energy mineral . This paper argues that events over the last decade, such as the demand for a New International Economic Order, the OPEC increase in crude oil prices and the growing international lobby on environmental issues especially relating to nuclear safety - will progressively lead to a major, long-lasting transformation of the energy scene world wide. This transformation will encompass demand, in terms of conservation and efficiency, the supply mix of the various energy minerals , the supply system and the structure of the different energy industries . It is already affecting the role of governments and reaching into the question of national sovereignty both of developed countries, such as the U.K., Norway and Australia, and the developing countries, thereby making energy minerals a key area of international relations.

Jan 1, 1978

By J. C. Kingston

Introduction The sliding-form method of erecting concrete structures was first devised and used in the early part of this century by the Sante Fe Railroad Company for the erection of a grain elevator at Santa Fe, New Mexico. A somewhat related principle has been employed for a number of years in shaft lining work and, to our knowledge, was perfected in Butte, Montana, but until the building of the concrete headframe at the Jeffrey mine of the Canadian Johns-Manville Company, Ltd., at Asbestos, Que., the method, as applied to surface structures, was quite foreign to the mining industry in Canada. The current shortage and cost of structural steel shapes has no doubt contributed more than any other single factor to the investigations that have led to the use of reinforced concrete as a headframe building material. Mining men in western Quebec and northern Ontario have shown a great deal of interest in the design and construction of the headframe at the East Sullivan mine in Bourlamaque township, Que., and we have had many queries regarding the methods used and, in particular, for an explanation of the sliding-form principle. This article is written in an attempt to set forth the conditions which were to be met; to explain the construction methods used, and to discuss the economy of concrete headframes as compared with the conventional steel structures with which the mining fraternity is familiar.

Jan 1, 1949

By Harold L. Gibson, David H. Watkinson

"Volcanogenic massive sulphide deposits of the Noranda Camp cur throughout the Noranda Shield Volcano but are concentrated and along the margins of the Noranda Cauldron. The deposits are realized along synvolcanic faults that also accommodated subsince and controlled the location of eruptive centres. Deposits within e 3 000 m thick Mine Sequence formed during a period of active volcanism and subsidence coinciding with the onset of two cauldron subsidence cycles. The Noranda Cauldron was a restricted site of 10malously high heat flow and structural permeability that favoured e development of a high-temperature hydrothermal system. Metals may have been derived from leaching of aquifer rocks by convecting a water or directly from a shallow underlying magma chamber, now presented by the Plavrian Pluton, that was at its highest position !thin the crust during cauldron subsidence. The deposits formed rough a combination of sulphide precipitation from exhaled fluid td replacement at and below the seafloor in a manner analogous to ose on the modern seafloor.RESUMESi les dépôts de sulfures massifs volcano gènes du camp minier de ~uyn-Noranda sont présents dans les différentes parties du volcanluclier de Noranda, ils se trouvent concentres toutefois, en plus ·and nombre, sur le pourtour de la caldeira (cauldron) de Noranda. ~s dépôts sont localises le long des failles synvolcaniques qui ont cilite la subsidence et contrôle la position des centres d’éruption.~dépôts situes dans la séquence des mines (3 000 m d’épaisseur) sont formes durant un épisode d' activité volcanique et de subsiden qui coïncide avec l' amorce de deux cycles d' affaissement de la rldera (cauldron) de Noranda. Celle-ci Jut le site exclusif d’unflux : chaleur anormalement élevé et d’une perméabilité d’origine cucturale qui ont favorise le développement d’un système hydrothermal a haute température. Les métaux proviennent soit directement d’une chambre magmatique situee afaible profondeur, so it d’un lessivage des roches de l’aquifère par l’eau de mer circulant par convection. Cette chambre magmatique, représentée maintenant par le pluton de Flavrian, se trouvait à son niveau le plus élevé dans la croute au moment de l’affaissement de la caldeira (cauldron). Les dépôts se sont constitués par un mecanisme combinant remplacement et précipitation de sulfures à partir des fluides exhalatifs, au niveau ou au-dessous du plancher océanique, de la même manière que se forment de nos jours, les dépôts de sulfures massifs au fond des océans."

Jan 1, 1990

SME-AIME Fall Meeting and Exhibit

Jan 9, 1979

By Raymond F. Gray, Victor J. Hoffman, Richard J. Bagan, Harold L. McKinley

The first indication of tungsten in the Bishop area was the discovery of scheelite concentrations in a gold placer operation in the ( since named) Tungsten Hills in 1913. After early intermittent production, the deposits of the district were slowly discovered and developed. The Pine Creek mine, located in 1916 and under the direction of Union Carbide Corporation since 1935, became the principal producer in the district. By the end of 1965, the total production of the district had reached 3,450,932 units of WO3, 17,071,242 pounds of molybdenum, and 19,599,110 pounds of copper. The topography of the district is characterized by its extreme relief, ranging in elevation from 13,986 feet to about 4400 feet in the Mount Tom quadrangle. The present topography is the result of the uplift and erosion of the Sierra Nevada and the great subsidence of the Owens Valley with its related deposition and volcanism. The general structure of the pre-Tertiary rocks consists of a series of tightly-folded metasedimentary and metavolcanic rock remnants surrounded by exposed plutons ranging in composition from hornblende gabbro to alaskite. The metasedimentary rocks consist of low- to intermediate-grade metamorphic equivalents of fine-grained sediments deposited during the Paleozoic era in a miogeosynclinal environment. Later volcanics were deposited in a eugeosyncline. The ore bodies in the Bishop district consist of scheelite-bearing tactite formed by the pyrometasomatic replacement* of calcareous sediments along the contact with an acidic granitic intrusive. A number of the metasedimentary remnants have had tungsten deposited along their edges.

Jan 1, 1968

By Z. G. He, S. H. Chen, P. Egger

A new model for hollow rock bolts which comprises rock material, hollow bolt material, bolt/rock interface, is developed on the base of the composite element method (CEM). The main advantage of the new model is that it can be incorporated into the conventional finite element analysis. So the mesh generation of bolted rock structures becomes more convenient and feasible, which is very important in the optimisation of reinforcement design: the mesh can be kept unchanged when the number and orientation of bolts are adjusted. The comparison of the calculation results with a conventional FE approach shows the robustness of the proposed method. Un nouveau modèle numérique de boulons creux comprenant la roche, le matériau du boulon creux et l’interface roche / boulon est développé sur la base de la méthode des éléments composites (CEM). L’avantage principal du nouveau modèle est la possibilité de l’incorporer dans une analyse aux éléments finis conventionnelle. Ainsi la génération du maillage d’une structure rocheuse ancrée devient plus simple ce qui est très important pour une optimisation du projet : en cas d’ajustement du nombre et de l’orientation des boulons, le maillage reste inchangé. La comparaison de résultats de calcul avec ceux obtenus par un code aux éléments finis conventionnel montre la robustesse de la méthode proposée. Auf der Grundlage der Verbund-Element-Methode (CEM) wird ein neues Modell für hohle Reibungsanker entwickelt, das den Fels, das Ankermaterial und die Kontaktfläche Fels / Anker umfasst. Der Hauptvorteil des neuen Modells ist die Möglichkeit, es in eine konventionelle FE-Analyse einzubetten. So wird die Netz-Generierung für verankerte Fels-Bauwerke einfacher, was für die Optimierung des Verankerungs-Projekts von Wichtigkeit ist: wenn Zahl und Orientierung der Anker variiert werden, bleibt das Netz unverändert. Der Vergleich von Rechenergebnissen mit solchen aus einer konventionellen FE-Rechnung zeigen die Robustheit der vorgestellten Methode.

Jan 1, 2003

By D. I. Bleiwas

Bureau of Mines personnel evaluated the potential availability of nickel from 151 deposits in 18 market economy countries and selected 126 for detailed analyses. An evaluation was made of tonnage-cost relationships indicating the quantity of nickel available at various total costs of production expressed in dollars per pound nickel, including a 15-pct rate of return on the invested capital. The 126 deposits studied contain approximately 73 million metric tons (t) of nickel. An estimated 52 million t is available from laterite deposits, of which less than 2 pct could be produced at $3.50/lb Ni, about equal to the average published price of nickel in 1981. Approximately 21 million t of nickel is available from sulfide deposits, of which about 10.0 million t can be produced at $3.50/lb. Sensitivity studies performed for both laterite deposits and sulfide deposits indicate that the total cost of nickel from laterites is most sensitive to increases in energy costs, and that sulfides are most sensitive to increases in labor costs; sulfides are also sensitive to changes in byproduct revenues. In 1983 the Nickel Mountain mine in Oregon was the only U.S. producer, though development continued on the Gasquet property in California. Of the total 5.1 million t of recoverable nickel in the United States, about 20 pct is available at or below $3.50/lb.

Jan 1, 1984

By J. A. Taylor, R. J. Fowell

Abstract: The amount of published literature pertaining to the field of rock mechanics has increased markedly in recent years. Whilst computer applications aid our understanding of the mechanisms of pillar instability, the applications do not take into account the effect of time; thus the determined pillar factor of safety has limited meaning. A more realistic approach would be to consider pillar stability in terms of time to failure. However such an approach would require a reasonable estimate of the in-situ pillar mass strength and a validated methodology linking the time to failure with in-situ pillar mass strength and the geometric layout of the working. Résumé: Le volume de bibliographie au sujet de la mécanique des roches a augmenté considérablement ces derniêres années. Alors que des modeles informatiques aident a la compréhension des mécanismes d'instabilité de pilliers, ces modèles ne prennent pas en compte les effets du temps; ainsi, la determination du coefficient de surete du pillier a un sens limité. Une approche plus réaliste devrait considérer la stabilité du pillier en fonction du temps de défaillance. Cependant une telle approche exigerait une estimation raisonnable de la resistance du massif rocheux du pillier ainsi qu'une méthodologie qui lie le temps de défaillance avec la résistance in-situ du massif rocheux du pillier et la géometrie de l'excavation souterraine. Zusammenfassung: Die Anzahl der Veröffentlichungen auf dem Gebiet der Felsmechanik ist in jüngster Zeit sehr gestiegen. Computerprogramme sind wertvoll um den Mechanismus der Pfeilerunbeständigkeit zu verstehen, aber sie vernachlässigen den Zeiteffekt. Daher haben die errechneten Sicherheitsfaktoren der Pfeiler nur begrenzte Bedeutung. Eine realistischere Bewertung wäre, die Stabilität der Pfeiler auf Grund der Zeit bis zum Verfall zu beurteilen. So ein Verfahren würde eine Schätzung der in-situ Gebirgsfestigkeit und eine validierte Methologie, die die Zeit zum Verfall in Abhängigkeit der in-situ Pfeilerfestigkeit und der geometrischen Auslage der Grube zusammenbringt, brauchen.

Jan 1, 2003

By H. T. Rall

This report summarizes a systematic 20-year study of the organic sulfur compounds in Wasson, Texas, crude oil and, to a lesser extent, of three other crude oils, that has culminated in some 200 individual sulfur-compound identifications. The development and application of special separation and identification techniques generally suitable for the characterization of sulfur compounds in any crude oil are discussed. This report reviews early sulfur literature covering petroleum sulfur compound identifications completed before this study was begun, and cites 58 papers resulting from this work. The sulfur compounds in petroleum, both as to type and quantity, have long been of concern to the petroleum industry, and such compositional data are not only of theoretical interest, but also of practical value.

Jan 1, 1972

By M. Drozd, M. Somppi, Z. F. Yamak

"Activated carbon is used to recover gold in solution from various gold circuit designs including carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) processes; however, the characteristics and durability of the activated carbon can vary. Handling this medium poses challenges when fine carbon losses occur in the CIP, CIC, and CIL circuit discharge. Additionally, adsorbed gold on carbon fines can be lost to the discharge. The studies in this paper aim to standardize laboratory methods for testing activated carbon qualities specific to the gold industry. The investigation focused on size distribution, platelet content, wet attrition resistance, gold kinetics, and gold loading. The results demonstrate that a 96 h attrition test and a gold loading test form a basis for ranking carbon samples based on expected economic performance of the plant. ¦ KEYWORDS Activated carbon, Carbon attrition, Carbon ball-pan hardness, Carbon evaluation, Carbon fines loss, Carbon turnover RÉSUMÉ Le charbon actif sert à récupérer l’or en solution dans diverses conceptions de circuits de broyage d’or, notamment les procédés de charbon en pulpe (CIP, de l’anglais carbon-in-pulp), de charbon en colonnes (CIC, de l’anglais carbon-in-column) et de lixiviation au carbone, ou charbon au lixiviat (CIL, de l’anglais carbon-in-leach). Toutefois, les caractéristiques et la durabilité du charbon actif varient. La manipulation de ce milieu pose des problèmes dès lors que se produisent des pertes de carbone à grain fin dans la décharge des circuits CIP, CIC et CIL. Par ailleurs, l’or adsorbé sur les fines de charbon peut se perdre durant la décharge. Les études réalisées dans le cadre de cet article visent à normaliser les méthodes de laboratoire pour tester les qualités du charbon actif spécifiques au secteur de l’exploitation aurifère. L’étude portait sur la composition granulométrique, la teneur des plaquettes, la résistance au frottement humide, la cinétique de l’or et l’adsorption de l’or, à savoir la capacité du charbon actif à adsorber l’or sur une période spécifique. Les résultats ont montré qu’un test de frottement de 96 heures et un test d’adsorption de l’or constituaient le fondement d’un classement des échantillons de carbone du point de vue économique en vue de trouver l’échantillon générant le meilleur rendement des usines. ¦ MOTS CLÉS charbon actif, dureté de la batée des billes de carbone, évaluation du carbone, perte de fines de charbon, renouvellement du carbone, résistance au carbone INTRODUCTION The use of activated carbon for gold extraction is among the most common processes in modern gold-milling plants. Although gold losses are inevitable in the milling process, operators often focus on reducing gold loss to tailings. One focus area that is important in gold recovery is optimizing the use of activated carbon and examining potential changes to realize improved economics for carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) processes. Granular activated carbon (Figure 1) is widely used for gold extraction from slurries containing gold-cyanide complexes. This activated carbon—produced from charred coconut shells—is well suited because of its adsorption kinetics, gold-loading capacity, attrition resistance, and ability to be reactivated. The extraction process using activated carbon technology involves adsorbing gold from an aqueous leachate; the gold is dissolved using a cyanide salt and consequently a dicyanoaurate(I) ion (Au(CN)2–) is formed, as noted in equation 1."

Jan 1, 2019