Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Mining Publication: Surface Magnetic Field Noise Measurements at Geneva Mine

NOTE: This page is archived for historical purposes and is no longer being maintained or updated. Contact OMSHR if you need an accessible version of this document.

September 1974

Image of publication Surface Magnetic Field Noise Measurements at Geneva Mine

Measurements of surface magnetic field noise were made at various locations over the Geneva Coal Mine near Price, Utah, on June 12, 1973. The locations selected were on the surface over emergency locator beacons underground at depths between 350 meters (1150 ft.) and 488 meters (1600 ft.). The surface terrain where these measurements were made was mountainous, and access was difficult. There were no power lines within several miles, and the weather was clear; therefore, the magnetic noise levels were about as low as will normally occur. Results of measurements of distant sferics indicate rather sharp cutoff frequencies below which broadband, impulsive noise is attenuated. The mechanism of propagation for this noise above the daytime cutoff frequency of 3500 Hz and the nighttime cutoff frequency of 1700 Hz is deduced to be a waveguide formed by the D or E layers of ionosphere as an upper plane and the earth as a lower plane. The measurement systems used are similar to those used earlier. The technique is to record broadband, analog signals, digitize the data, and use a fast-Fourier transform to obtain spectral plots. This technique is novel in that it can measure simultaneously all magnetic field energy within a limited portion of the spectrum for a limited time, and, after processing, reproduce the events occurring in that time interval in great detail.

Authors: JW Adams, WD Bensema, NC Tomoeda

Contract/MOA ReportSeptember - 1974

  • Adobe Acrobat - Portable Document Format (.PDF)

    1.43 MB

NIOSHTIC2 Number: 10001388

National Bureau of Standards. U.S. Bureau of Mines contract No. H0133005. NBSIR 74-369. NTIS No. Com/741-1688, 1974; :1-40

 
Contact Us:
  • Office of Mine Safety and Health (OMSHR)
  • National Institute for Occupational Safety and Health (NIOSH)
  • Centers for Disease Control and Prevention
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
  • New Hours of Operation
    8am-8pm ET/Monday-Friday
    Closed Holidays
  • omshr@cdc.gov
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #