A Measurement Method for Determining Absorption Coefficients for Underground Mines

Details

• Personal Author:
  Cole, Gregory P. ; Kovalchik, Peter G. ; Matetic, Rudy J. ; Smith, Adam K.
• Description:
  Previous studies conducted by the National Institute for Occupational Safety and Health (NIOSH) have shown that approximately 90% of coal miners and 49% of metal/nonmetal miners had a hearing impairment by age 50. Mine workers are exposed to additional noise levels underground due to the reflection of machine generated noise that would otherwise dissipate in an above ground setting. Determining the sound absorption coefficients is essential in modeling the sound field in an underground mining environment. Sound absorption is a measure of the amount of acoustic energy that strikes a surface and is absorbed, rather than reflected. The acoustic environment that mining machines operate in is a critical factor affecting the sound pressure level exposure for mining machine operators. Impedance tube testing is an inappropriate method for determining underground absorption coefficients due to the brittle composition of some of the materials such as coal and slate. Classic absorption coefficient estimation using T60 measurements will not work well in an underground environment because the theory assumes: a finite room, a diffuse field, and relatively uniform absorption. None of these assumptions are true in an open-ended mine entry. This paper will present a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz. The absorption coefficients will be essential for determining and predicting potential overexposure to machine operators in different mine environments. [Description provided by NIOSH]
• Subjects:
  Acoustics Coal Coal Mining Hearing Loss, Noise-Induced Metals Mining Noise Noise, Occupational Occupational Health Safety
• Keywords:
  Acoustic-absorption Acoustical-measurements Coal-mining Metal-mining Miners Mining-equipment Mining-industry Noise-control Noise-exposure Noise-induced-hearing-loss Noise-measurement Nonmetal-mining Sound-attenuation Sound-propagation Underground-miners Underground-mining

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• Series:
  Mining Publications
• ISBN:
  9781604231366
• Publisher:
  International Institute of Noise Control Engineering
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  Hawaii ; OSHA Region 3 ; OSHA Region 9 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRL - Pittsburgh Research Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  8
• NIOSHTIC Number:
  nn:20031467
• Citation:
  Inter-Noise 2006. The 35th International Congress and Exposition on Noise Control Engineering, December 3-6, 2006, Honolulu, Hawaii. West Lafayette, IN: International Institute of Noise Control Engineering, 2007 Aug; 8:5094-5102
• Federal Fiscal Year:
  2007
• NORA Priority Area:
  Disease and Injury: Hearing Loss
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b553800a9b9cc01d8b2327dc148435c262dad7d8837f62f61f2b5c0a0f4b45ad27dd2869dd7fc4c7a6a4da071436f24bae0ca554facfcf268f2dd50da6d22058
• Download URL:
  https://stacks.cdc.gov/view/cdc/226703/cdc_226703_DS1.pdf
• File Type:
  [PDF - 149.53 KB ]