Results 71 - 80 of 119

• A Spatial/Spectral Domain Microwave Coal Seam Imaging Sensor-Progress in Signal Processing
  7/1/1994 - Conference papers
  The paper, presents the results of roof coal thickness measurements in underground mines and rib coal thickness measurements in highwall mines. The microwave sensor described uses a unique spatial modulation scheme created by antenna motion, along with ...
• Advances in Mine Emergency Communications
  4/1/1994 - Conference papers
  To address communicating while wearing an SCSR, two-way, FM radios were built in and improved mouthpieces were added to the SCSR to improve the ability to communicate. Prototypes we built and tested. Leaky feeder systems are also described.
• 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 (...
• 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...
• 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...
• Field Test of a Post-Disaster Communication System
  12/1/1983 - Contract reports, Open File Reports
  A new postdisaster communication and location system using through-the-earth electromagnetic wave propagation was tested at the Bureau of Mines Lake Lynn Experimental Mine. This describes the testing process and findings.
• Development of a Phase Difference of Arrival Technique for Location of Trapped Miners
  9/1/1983 - Open File Reports
  Current technologies for locating trapped miners from the surface are either simple direction finders or time difference pulse systems that have accuracy limitations. Developing technologies using full-vector field measurements at several receiving poin...