Surface Magnetic Field Noise Measurements at Geneva Mine

Details

• Journal Article:
  Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, Contract No. H0133005
• Personal Author:
  Adams, John W. ; Bensema, W. D. ; Tomoeda, N. C.
• Description:
  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 atmospherics 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. [Description provided by NIOSH]
• Subjects:
  Electromagnetic Phenomena Mining Occupational Health Radiation Radio Waves Safety
• Keywords:
  Mining-industry; Electromagnetic-energy; Electromagnetic-fields; Electromagnetic-interference; Electromagnetic-radiation; Statistical-analysis; Underground-mining; Radio-waves
• Source:
  Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, Contract No. H0133005, :1-35
• Series:
  Mining Publications
• Document Type:
  Text
• Funding:
  U. S. Bureau of Mines working fund agreement HO 133005
• Genre:
  Final Contract Report
• Place as Subject:
  Colorado ; OSHA Region 3 ; OSHA Region 8 ; Pennsylvania ; Utah
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRC - Pittsburgh Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  40 pdf apges
• NIOSHTIC Number:
  nn:10001388
• NTIS Accession Number:
  COM-741-1688
• Federal Fiscal Year:
  1974
• Performing Organization:
  National Bureau of Standards
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4371004aa1b70056d3768d7acd0a8344e5ae2aa938611bc83eed1d589a85e3e6fb7bffcebf95d11d5def4f6e3c13b745c967a8984c40d3211b3e37797505aa48
• Download URL:
  https://stacks.cdc.gov/view/cdc/8863/cdc_8863_DS1.pdf
• File Type:
  [PDF - 1.13 MB ]