928 resultados para Tramway Mine
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Sequential pattern mining is an important subject in data mining with broad applications in many different areas. However, previous sequential mining algorithms mostly aimed to calculate the number of occurrences (the support) without regard to the degree of importance of different data items. In this paper, we propose to explore the search space of subsequences with normalized weights. We are not only interested in the number of occurrences of the sequences (supports of sequences), but also concerned about importance of sequences (weights). When generating subsequence candidates we use both the support and the weight of the candidates while maintaining the downward closure property of these patterns which allows to accelerate the process of candidate generation.
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While mining is a major component of the northern Canadian economy, including the contemporary mixed economy of Aboriginal communities, it often leaves legacies of environmental and economic transformation that persist after closure. The legacies of historical mines in northern Canada challenge industry claims of sustainability. This thesis addresses how industrial mineral development and closure continue to affect local environments and economies after abandonment. The abandoned Pine Point mine in the Northwest Territories provides a case study for explaining the ongoing relationships among land cover, land use, and the post-industrial landscape. Drawing from landscape ecology and micropolitical ecology, I adopt an interdisciplinary approach to examine environmental and socioeconomic changes in the wake of industrial development and closure at Pine Point. The results show that passive reclamation is not sufficient for restoring ecological function in a subarctic environment. Land use, however, persists as land users adapt to the post-industrial landscape despite grave concern about its environmental condition. If mining is to be considered sustainable, decommissioning and reclamation must explicitly account for long-term environmental transformation as well as ongoing post-industrial land use, particularly in Aboriginal contexts.
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General note: Title and date provided by Bettye Lane.
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General note: Title and date provided by Bettye Lane.
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Saipan, situated about 15° N. and 146° E., is one of the larger and more southerly of the Mariana Islands. The 15 small islands of this chain are strung along an eastwardly convex ridge for more than 400 miles north to south, midway between Honshu and New Guinea and about 1,200 miles east of the Philippines. Paralleling this ridge 60 to 100 miles further east is a deep submarine trench, beyond which lies the Pacific Basin proper. To the west is the Philippine Sea, generally deeper than 2,000 fathoms. The trench coincides with a zone of negative gravity anomalies, earthquake foci occur at increasing depths westward from it, and silica- and alumina-rich volcanic rocks characterize the emergent island chain itself. The contrast between these features and those of the Pacific Basin proper to the east is held to favor the conclusion that the Mariana island arc and trench define the structural and petrographic front of Asia.
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The Todoroki Mine is situated about 25 kilometers to the south-east of Ginzan railway station in Siribesi Province, Hokkaido. The author analysed an interesting specimen of black manganese-ore which had a fractured surface which looked like that of a broken piece of wood. This new manganese mineral was studied in its form, physical properties and chemical composition. The author later named this mineral form as "todorokite".
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Manganese deposits are abundant in various places in the Oshima Peninsula southwest of Hokkaido. This is particular the case of Todoroki Mine situated about 25 kilometers to the south-east of the Ginzan railway station in Siribesi Province. It consists of manganese beds intermixed with a tertiary volcanic tuff complex overlaying granite.
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The roasting of gold-bearing arsenopyrite at Giant mine (Northwest Territories) between 1949 and 1999 released approximately 20,000 tonnes of toxic arsenic-bearing aerosols in the local aerial environment. Detailed examination of lake sediments, sediment porewaters, surface waters and lake hydrology sampled from three lakes of differing limnological characteristics was conducted in summer and winter conditions. Samples were analyzed for solid and dissolved elemental concentrations, speciation and mineralogy. The three lakes are located less than 5km from the mine roaster, and downwind, based on predominant wind direction. The objective of the study was to assess the controls on the mobility and fate of arsenic in these roaster-impacted subarctic lacustrine environments. Results show that the occurrence of arsenic trioxide in lake sediments coincides with the regional onset of industrial activities. The bulk of arsenic in sediments is contained in the form of secondary sulphide precipitates, with iron oxides hosting a minimal amount of arsenic near the surface-water interface. The presence of geogenic arsenic is likely contained as dilute impurities in common rock-forming minerals, and is not believed to be a significant source of arsenic to sediments, porewaters or lake waters. Furthermore, the well correlated depth-profiles of arsenic, antimony and gold in sediments may help reveal roaster impact. The soluble arsenic trioxide particles contained in sediments act as the primary source of arsenic into porewaters. Dissolved arsenic in reducing porewaters both precipitate as secondary sulphides in situ, and diffuse upwards into the overlying lake waters. Arsenic diffusion out of porewaters, combined with watercourse-driven residence time, are estimated to be the predominant mechanisms controlling arsenic concentrations in overlying lake waters. The sequestration of arsenic from porewaters as sulphide precipitates, in the study lakes, is not an effective process in keeping lake-water arsenic concentrations below guidelines for the protection of the freshwater environment and drinking water. Seasonal impacts on lake geochemistry derive from ice covering lake waters, cutting them off from of atmospheric oxygen, along with the exclusion of solutes from the ice. Such effects are limited in deep lakes but are can be an important factor controlling arsenic precipitation and mobility in ponds.
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The hydrothermal liquefaction(HTL) of algal biomass is a promising route to viable second generation biofuels. In this investigation HTL was assessed for the valorisation of algae used in the remediation of acid mine drainage (AMD). Initially the HTL process was evaluated using Arthrospira platensis (Spirulina) with additional metal sulphates to simulate metal remediation. Optimised conditions were then used to process a natural algal community (predominantly Chlamydomonas sp.) cultivated under two scenarios: high uptake and low uptake of metals from AMD. High metal concentrations appear to catalyse the conversion to bio-oil, and do not significantly affect the heteroatom content or higher heating value of the bio-oil produced. The associated metals were found to partition almost exclusively into the solid residue, favourable for potential metal recovery. High metal loadings also caused partitioning of phosphates from the aqueous phase to the solid phase, potentially compromising attempts to recycle process water as a growth supplement. HTL was therefore found to be a suitable method of processing algae used in AMD remediation, producing a crude oil suitable for upgrading into hydrocarbon fuels, an aqueous and gas stream suitable for supplementing the algal growth and the partitioning of most contaminant metals to the solid residue where they would be readily amenable for recovery and/or disposal.
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The hydrothermal liquefaction(HTL) of algal biomass is a promising route to viable second generation biofuels. In this investigation HTL was assessed for the valorisation of algae used in the remediation of acid mine drainage (AMD). Initially the HTL process was evaluated using Arthrospira platensis (Spirulina) with additional metal sulphates to simulate metal remediation. Optimised conditions were then used to process a natural algal community (predominantly Chlamydomonas sp.) cultivated under two scenarios: high uptake and low uptake of metals from AMD. High metal concentrations appear to catalyse the conversion to bio-oil, and do not significantly affect the heteroatom content or higher heating value of the bio-oil produced. The associated metals were found to partition almost exclusively into the solid residue, favourable for potential metal recovery. High metal loadings also caused partitioning of phosphates from the aqueous phase to the solid phase, potentially compromising attempts to recycle process water as a growth supplement. HTL was therefore found to be a suitable method of processing algae used in AMD remediation, producing a crude oil suitable for upgrading into hydrocarbon fuels, an aqueous and gas stream suitable for supplementing the algal growth and the partitioning of most contaminant metals to the solid residue where they would be readily amenable for recovery and/or disposal.
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Here, we report the draft genome sequence of Staphylococcus succinus strain CSM-77. This moderately halophilic bacterium was isolated from the surface of a halite sample obtained from a Triassic salt mine.
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This study investigated the separation of uranium and other elements in high concentrations from acid mine waters at Caldas Uranium Mining, in the southeast of Brazil, using nanofiltration membranes. Nanofiltrarion is widely used in water treatment due to the lower energy requirements and higher yields than reverse osmosis. Separation characteristics are dependent on both the molecular size and charge of the dissolved species in the feed solution as well as membrane properties. In this investigation the potential of nanofiltration to removed dissolved species like uranium from acid mine water drainage was measured. Two composite aromatic polyamide commercially membranes of FilmTec/Dow were tested and it found that uranium rejections of greater than 90% and also showed potential for the separation of aluminum and manganese.
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L’étude porte sur les retombées économiques de la mine de Voisey’s Bay sur les conditions socioéconomiques des communautés de Rigolet, Makkovik, Hopedale, Nain et de Postville. Elle adopte une approche multidimensionnelle à la fois descriptive et comparative. Les données utilisées proviennent des recensements de la population de 1991, 1996, 2001 et de 2006 conduits par Statistique Canada. Elle utilise aussi les données de l’Enquête nationale auprès des ménages de 2011. Les données internes à la mine proviennent des Rapports de responsabilités sociales de la firme VBNC qui se charge d’exploiter la mine. Nous avons également en recours aux données des rapports du Gouvernement du Nunatsiavut depuis sa mise en place en 2005. Cette étude s’inscrit dans un contexte d’exploitation des ressources naturelles. Elle montre que, contrairement à des considérations voulant que celles-ci constituent une source de richesses, leurs effets sur les conditions socioéconomiques des communautés locales restent mitigés. Les firmes minières s’acharnent à maximiser leurs profits et les conditions de vie des communautés locales n’en bénéficient que partiellement. Pour notre étude, nous faisons l’hypothèse que cette mine ait eu de nombreuses retombées directes ou indirectes (emplois, achats de biens et services, taxes minières, investissements et redevances) et que celles-ci ont modifié les conditions de vie des communautés concernées. Nous avons opté pour une méthodologie basée sur un modèle de retombées économiques de la mine de Voisey’s Bay; un outil conçu avec l’inspiration de la grille d’évaluation des projets miniers, gaziers et pétroliers sur les conditions socioéconomiques de Paul Kishchuk. Ce modèle nous a permis d’analyser les effets de Voisey’s Bay sur la démographie, le marché du travail, la scolarité, le revenu et le logement. Les dimensions identifiées font état d’une légère amélioration sur les conditions de vie des communautés, bien que l’effet ne puisse pas être totalement attribué à la mine, étant donné le rôle important joué par le Gouvernement du Nunatsiavut depuis sa création.
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L’usine Niobec traite un minerai de pyrochlore porteur de niobium pour produire le ferro-niobium utilisé pour la fabrication d’acier. L’usine récupère environ 60% des minéraux de niobium. Les rejets contiennent du niobium et d’autres espèces minérales potentiellement valorisables. Les travaux présentés dans ce mémoire visent à identifier les espèces pouvant être valorisées dans les rejets de Niobec dont les plus prometteurs sont les éléments de terres rares, les minéraux de niobium et l’apatite. Dans le but de concentrer l’apatite des rejets de l’usine, une analyse chimique des rejets a permis de cibler comme flux d’intérêt les particules de dimension supérieure à 0,038mm dans le concentré de carbonates et les rejets du circuit de flottation du pyrochlore. La méthode utilisée pour valoriser les phosphates est la flottation. Les meilleurs résultats ont été obtenus par flottation directe des minéraux de phosphate du concentré de carbonates dans les rejets de Niobec. Le collecteur utilisé est un acide gras de type AERO 6493 avec un mélange d’amidon de tapioca et de NaOH utilisé comme déprimant pour les carbonates. Ces conditions ont permis de produire un concentré d’apatite titrant entre 30 à 32 % P2O5 avec un rendement de 50 à 60% du P2O5 contenue dans le concentré de carbonates. La teneur en MgO dans le concentré d’apatite est comprise entre 3 et 4% comparativement à 15% dans l’alimentation. Puisque le MgO est principalement associé à la dolomie ces résultats confirment une bonne dépression de ce minéral lors de la flottation de l’apatite du concentré de carbonates. La flottation de l’apatite à partir des rejets du pyrochlore n’a pas permis d’obtenir un concentré de valeur commerciale. Le meilleur résultat obtenu lors des essais de flottation sur les rejets pyrochlore correspond à une teneur de 14%avec un rendement de 53% P2O5. Les résultats obtenus montrent toutefois le potentiel associé à la récupération des minéraux de phosphates et justifient la poursuite des travaux, cette fois, moins exploratoires que les travaux rapportés dans ce mémoire.
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For fifty years (1949–99) the now-abandoned Giant Mine in Yellowknife emitted arsenic air and water pollution into the surrounding environment. Arsenic pollution from Giant Mine had particularly acute health impacts on the nearby Yellowknives Dene First Nation (YKDFN), who were reliant on local lakes, rivers, and streams for their drinking water, in addition to frequent use of local berries, garden produce, and medicine plants. Currently, the Canadian government is undertaking a remediation project at Giant Mine to clean up contaminated soils and tailings on the surface and contain 237,000 tonnes of arsenic dust that are stored underground at the Giant Mine. Using documentary sources and statements of Yellowknives Dene members before various public hearings on the arsenic issue, this paper examines the history of arsenic pollution at Giant Mine as a form of “slow violence,” a concept that reconfigures the arsenic issue not simply as a technical problem, but as a historical agent of colonial dispossession that alienated an Indigenous group from their traditional territory. The long-term storage of arsenic at the former mine site means the effects of this slow violence are not merely historical, but extend to the potentially far distant future.