937 resultados para Tin mines and mining
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Mode of access: Internet.
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1869-70 has half-title: Third biennial report of the state mineralogist.
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At head of title: 89th Congress, 1st session, Committee print.
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Includes bibliography.
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At head of title: Canada, Department of mines, Geological survey branch ...
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At head of title: 88th Cong., 2d sess. Committee print.
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-1898 include also the reports of the State Inspectors of Mines; 1899-1907, Report of the Illinois Free Employment Offices; 1917- , reports of the Miners' Examining Board and the Mine Rescue and First Aid Division (formerly Mine Rescue Station Commission).
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Mode of access: Internet.
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Mode of access: Internet.
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Title varies slightly
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Mode of access: Internet.
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Mode of access: Internet.
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"July 12, 1988" -- pt.2.
USGS geochemical studies outline mineral potential and environmental hazards in southeastern Oregon.
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Mode of access: Internet.
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A concept has been developed where characteristic load cycles of longwall shields can describe most of the interaction between a longwall support and the roof. A characteristic load cycle is the change in support pressure with time from setting the support against the roof to the next release and movement of the support. The concept has been validated through the back-analysis of more than 500 000 individual load cycles in five longwall panels at four mines and seven geotechnical domains. The validation process depended upon the development of new software capable of both handling the large quantity of data emanating from a modern longwall and accurately delineating load cycles. Existing software was found not to be capable of delineating load cycles to a sufficient accuracy. Load-cycle analysis can now be used quantitatively to assess the adequacy of support capacity and the appropriateness of set pressure for the conditions under which a longwall is being operated. When linked to a description of geotechnical conditions, this has allowed the development of a database for support selection for greenfield sites. For existing sites, the load-cycle characteristic concept allows for a diagnosis of strata-support problem areas, enabling changes to be made to set pressure and mining strategies to manage better, or avoid, strata control problems. With further development of the software, there is the prospect of developing a system that is able to respond to changes in strata-support interaction in real time.