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Results 31 - 40 of 42
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7/1/1980 - Conference papersField studies have been conducted in a large number of coal mines throughout the U.S. to determine the effectiveness of electromagnetic techniques in locating men trapped underground following a mine disaster.
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7/1/1979 - Contract reports, Open File ReportsThis report describes a complete system design for medium frequency ( MF) wireless radio systems for use in coal mines. The emphasis is on AC mines where no trolley wire exists and, for which, conventional trolley phone communications cannot be used. Th...
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10/1/1978 - Contract reportsThis document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system.
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9/1/1978 - Contract reportsThis report covers antenna design, analysis, and development work suited for use with a wireless radio communication system operating at medium frequency. The work includes the test and evaluation of prototype vehicular antennas developed during the pro...
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1/1/1978 - Peer reviewed journal articlesExtensive analysis of mine-communications systems has identified specific areas, in particular the excessive times required to locate key personnel underground, the inadequacy of existing phone systems in terms of capacity and privacy and the inability ...
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9/1/1977 - Contract reportsAn investigation was made of the feasibility of developing compact transmit antennas and/or other means to efficiently couple VLF to MF band radio energy between portable wireless communication units in coal mines. The completely wireless communication ...
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9/1/1977 - Contract reportsThis report describes magnetic field measurements in the Helvetia Coal Co. Lucene No. 8 Mine for purposes of deriving a mapping of the magnetic field strength covering the major haulageways which contain conductors.
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1/1/1977 - Conference papersThis report is a comprehensive summary of the results of the propagation measurements program conducted for the Bureau of Mines.
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8/1/1976 - Conference papersA brief description is given of various Bureau of Mines research activities that have begun since July 1974 and are not being reported on by others at the Third West Virginia University (WW) Conference on Coal Mine Electrotechnology.
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7/1/1975 - Contract reportsThe applicability of voice bandwidth compression techniques to mine wireless communication systems is examined. Promise has been attached to such techniques because the lessened bandwidth gave hope for lessened received noise and hence increased operati...
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Content source: National Institute for Occupational Safety and Health, Mining Program