Results 291 - 300 of 326

• Propagation of EM Signals in Underground Metal/Non-Metal Mines: Magma Copper Company - San Manuel Mine
  4/1/1981 - Contract reports
  This report presents test results, data evaluations, and typical system performance expectations based on wireless electromagnetic propagation measurements performed in the MAGMA Copper Company San Manuel mine near Tucson, Arizona during March 30 throug...
• The Implementation of UHF Radio Communications and CCTV Monitoring Systems in a Room and Pillar Metal/Non-metal Mine
  3/1/1981 - Contract reports
  This report describes the design and implementation of UHF radio and closed-circuit television systems in the Black River room and pillar limestone mine near Butler, Pendleton County, Kentucky.
• Data Security for In-Mine Transmission: Final Report - Part I
  2/1/1981 - Contract reports, Open File Reports
  A survey of electromagnetic noise reports was performed and a summary of the results are given.
• Propagation of EM Signals in Underground Metal/Non-Metal Mines
  1/1/1981 - Contract reports
  This report describes the results of a measurement and analysis program to characterize wireless radio transmission in metal-nonmetal mines over a wide frequency range from 0.2 to 1,000 mhz and over a variety of mine environments.
• Development of a Visual Display and Control System
  10/1/1980 - Contract reports
  The object of this program was to extend the capabilities of visual paging systems both in size and functions in mines. The system developed uses the mine pager phone line for communication, monitoring, and remote control. The system was designed to be ...
• Detection of Trapped Miner Electromagnetic Signals Above Coal Mines
  7/1/1980 - Contract reports
  This report assesses the expected detectability, on the surface above mines, of electromagnetic signals produced in the 630- to 3,030-hz frequency band by a rescue transmitter activated by miners trapped underground. The implications of the results and ...
• An Evaluation of Leaky Feeder Communication in Underground Mines
  6/1/1980 - Contract reports
  The objective of this project was to develop technical data and evaluate performance and utility of leaky feeder communications systems currently used in U.S. underground mines.
• Electromagnetic Location Systems for Metal/Non Metal Mines
  1/15/1979 - Contract reports
  Characteristics of metal-nonmetal mines were evaluated to determine the suitability of applying the Bureau of Mines electromagnetic (em) location system to locating trapped miners.
• Improved Rail Haulage Communications
  10/1/1978 - Conference papers
  An analysis is made of the trolley line as a communications line, and methods of improving its characteristics are discussed.
• Medium-Frequency Propagation in Coal Mines
  8/1/1978 - Conference papers
  Medium-frequency (MF) waves can propagate in a coal seam, bounded above and below by conducting rock, in an approximate transverse electro-magnetic (TEM) transmission-line mode with the electric field vertical and the magnetic field horizontal. The theo...