Results 211 - 220 of 222

• 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 ...
• 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.
• Propagation of EM Signals in Underground Mines
  1/1/1977 - Conference papers
  This report is a comprehensive summary of the results of the propagation measurements program conducted for the Bureau of Mines.
• An Electromagnetic System for Detecting and Locating Trapped Miners
  1/1/1976 - Reports of Investigations
  The theory of electromagnetic fields indicates such fields could be used to detect and locate trapped miners. To be useful, the hardware of the system must meet a number of requirements, including small size, intrinsic safety, and rugged construction. S...
• Technical Services for Mine Communications Research: Task A, Task Order No. 1 - Applicability of State-Of-The-Art Voice Bandwidth Compression Techniques for Wireless Mine Communication
  7/1/1975 - Contract reports
  The 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...
• Waveform Generator-Package and Receiver: Mancarried and Helicopter Receiver Portion
  11/1/1974 - Contract reports
  The report describes the design and building of 15 mancarried and 5 helicopter receivers that are used for trapped miner location during a mine disaster. Helicopters are equipped with six-channel receivers and used to detect transmitters carried by mine...
• Survey of Electromagnetic and Seismic Noise Related to Mine Rescue Communications: Volume I - Emergency and Operational Mine Communications
  9/1/1974 - Contract reports
  Volume I of this report deals with theoretical, experimental, and practical implementation aspects of the federal Bureau of Mines programs related to present and planned, emergency and operational, mine communications and miner location systems for unde...
• Survey of Electromagnetic and Seismic Noise Related To Mine Rescue Communications: Volume II - Seismic Detection and Location of Isolated Miners
  7/1/1974 - Contract reports
  Volume II of this report (Contract No. H0122026) presents the findings of a short intensive assessment performed during the fall of 1972. This assessment provided the federal Bureau of Mines with independent technical judgments regarding the potentials ...