Showing papers in "Mining Engineering in 1990"
Journal Article•
TL;DR: A drill system configuration capable of working in the arctic offshore environment was developed to evaluate the placer gold resources contained in the glacio-fluvial sediments offshore Nome, Alaska as mentioned in this paper.
Abstract: A drill system configuration capable of working in the arctic offshore environment was developed to evaluate the placer gold resources contained in the glacio-fluvial sediments offshore Nome, Alaska. This system is capable of working on the shore fast ice during the winter months and is deployed on a drill ship during the summer. Transfer of the drill between its summer and winter configurations is accomplished with a minimum of modification to the design. The system is designed around the Becker drill, a percussive reverse circulation drill capable of penetrating the indurated glacial sediments present in the offshore Nome environment. This drill has operated effectively to depths in excess of 50 metres below sea level. Since early 1987, in excess of 2,000 holes have been drilled using the system. The drill system, often operating in extreme weather conditions, has averaged approximately 10 holes per day of drill production. The ore reserves defined during these drilling programmes have resulted in the recovery of greater than 70,000 fine ounces of gold to date by the mining vessel BIMA.
6 citations
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4 citations
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3 citations
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TL;DR: In this paper, the authors developed a modeling scheme to simulate the hydrogeologic effects of mine design and development in unsaturated rock, using the UNSAT2 finite element computer program and hydrologic data from the site of a proposed mined-out waste repository at Yucca Mountain, NV.
Abstract: A modeling scheme is developed to simulate the hydrogeologic effects of mine design and development in unsaturated rock. Simulations are conducted using the UNSAT2 finite element computer program and hydrogeologic data from the site of a proposed mined-out waste repository at Yucca Mountain, NV. Results of the simulations are analyzed for: variations in the direction of ground water flow and in the distribution of pressure head caused by the design of the mined out openings; and mine design variables that affect the predicted rates of mine water inflow.
2 citations
Journal Article•
TL;DR: In this article, the Remote Placer Drill (RPD) system was successfully tested in the Nome offshore gold district, where it was deployed from the landing door of a modified tank landing craft and rigged for a single pass of 5 metres.
Abstract: A prototype Remote Placer Drill system of unique design has been successfully tested in the Nome offshore gold district. Conceived as a low cost, rapid drill sampling system for marine precious metal placer deposit exploration, the drill functions as a counter flush system. The objective was to reduce hitherto high marine drill sampling costs by developing a portable system that could be deployed from work vessels not specifically designed for drilling. The prototype underwent full operational tests. It was deployed from the landing door of a modified tank landing craft and rigged for a single pass of 5 metres. Extensive tests showed it to be an overall success, reliably sampling moderate ground less than 6 metres thick, using a smaller crew and operating in higher sea conditions.
2 citations
Journal Article•
TL;DR: The conversion of organic matter to petroleum by hydrothermal activity is an easy process,occurring in nature in many types of environments, such as the Guaymas Basin (Gulf of California), Escanaba Trough and Middle Valley (northeast Pacific), Bransfield Strait (Antarctica), and Atlantis II and Kebrit Deeps (Red Sea) as discussed by the authors.
Abstract: The conversion of organic matter to petroleum by hydrothermal activity is an easy process,occurring in nature in many types of environments. Geologically immature organic matter of mariner sediments is being altered by this process in Guaymas Basin (Gulf of California), Escanaba Trough and Middle Valley (northeast Pacific), Bransfield Strait (Antarctica), and Atlantis II and Kebrit Deeps (Red Sea). Contemporary organic detritus and viable microorganisms are also converted in part to petroleum-like products by the same process when present to become entrained, as for example on the East Pacific Rise at 13{degrees}N and 21{degrees}N and on the mid-Atlantic Ridge at 26{degrees}N. The hydrocarbon products (methane to asphalt) generated in all these areas have been elucidated in terms of composition, organic matter sources, and analogy to reservoir petroleum. This petroleum represents a major input of carbon to the primary chemosynthetic productivity of hydrothermal vent systems and may be important to interactions with metals in hydrothermal ore formation.
2 citations
Journal Article•
TL;DR: In this article, a history of the implication of l'etat dans le developpement de l'industrie charbonniere depuis le XIXeme siecle is presented.
Abstract: Historique de l'implication de l'etat dans le developpement de l'industrie charbonniere depuis le XIXeme siecle
1 citations