Results 71 - 80 of 131

• One-Way Fire Warning Alarm System for Underground Mines
  7/1/1990 - Conference papers
  An ideal fire warning alarm system for underground mines would be low cost, convenient, fast, reliable, and able to warn all underground workers. The U.S. Bureau of Mine devised a one way communication system employs a large loop antenna and transmitter...
• Interaction of Radio Transmissions on Mine Monitoring and Control Systems
  9/1/1986 - Contract reports
  This report describes the creation of an efficient method to determine if command, control, communication, and monitoring (3cm) equipment in coal, metal, and nonmetal mines is susceptible to radio frequency interference (RFI) from the medium-frequency (...
• Through-the-earth Electromagnetic Trapped Miner Location Systems. A Review
  7/1/1985 - Open File Reports
  Efforts to produce electromagnetic systems for the location of trapped miners underground and to communicate with them were surveyed, from the 1920s to 1981. Theoretical studies of through-the-earth electromagnetic transmissions are described as well as...
• Control and Monitoring Via Medium Frequency Techniques and Existing Mine Conductors
  7/1/1985 - Peer reviewed journal articles
  Medium frequency (MF) techniques have been successfully applied to the problem of radio voice communications in both coal and metal and nonmetal mines. MF techniques can also be applied to the areas of in-mine control and monitoring. Preliminary work in...
• EM Rescue (Location) System for Deep Mines: Phase II - Build and Test Breadboard Equipment
  10/1/1984 - Contract reports
  The purpose of this program is to extend electromagnetic (EM) techniques for use in locating miners trapped in mines as deep as 1000 m.
• A Medium Frequency Wireless Communication System for Underground Mines
  9/1/1984 - Contract reports, Open File Reports
  This report deals with information regarding a new Medium Frequency (MF) Wireless Communication System for underground mines. This new telecommunication system works on low loss electromagnetic wave propagation modes which allow it to provide quality ra...
• Adaptive-Noise-Cancellation Techniques for Through-the-Earth Electromagnetics: Volume III
  2/1/1984 - Contract reports
  An electromagnetic (EM) system for the location of trapped mine workers at coal-mine (300 m) depths has been developed.
• Electromagnetic Detection of Trapped Miners
  2/1/1984 - Peer reviewed journal articles
  The Bureau of Mines has conducted field studies in coal mines throughout the United States to determine the effectiveness of electromagnetic techniques in locating miners trapped underground following a mine accident.
• Underground Mine Communications, Control and Monitoring
  1/1/1984 - Information Circulars
  Since 1969, the Bureau of Mines has sponsored numerous programs aimed at improving methods of underground communication. This manual brings together relevant data from all previous reports, studies, and other sources, and presents these data in such a w...
• Medium Frequency Vehicular Control and Communications Systems for Underground Mines
  1/1/1984 - Conference papers
  Theoretical and experimental research sponsored by the U.S. Bureau of Mines shows that medium frequency (MF) electromagnetic (EM) signals propagate great distances in an underground environment such as a tunnel or mine. This propagation is enhanced by d...