Airblast-Overpressure Levels from Confined Underground Protection Blasts

Details

• Personal Author:
  Fletcher, Larry R. ; Olson, James J.
• Description:
  The Bureau of Mines recorded and analyzed overpressure levels for three production blasts at the White Pine Copper Mine, upper Michigan, to obtain representative data from single-heading blasts in a long, straight haulageway and to estimate the damage potential inherent in production blasts fired in close proximity to underground structures. Commercial pressure gages with a flat response to 1 khz were used with an fm tape recorder to record the overpressures from one dynamite and two ammonium nitrate-fuel, oil, 500-msec production blasts having zero-delay charge weights of about 75 lb (34 kg). The recorded waveforms from the underground blasts (1) were more complex than the typical free-air wave, (2) were of larger duration, and (3) had numerous secondary arrivals owing to reflections from the ribs and roof. The waveforms showed that the zero-delay charges produced the only high overpressures. [Description provided by NIOSH]
• Subjects:
  Occupational Health Safety
• Series:
  Mining Publications
• Subseries:
  Report of Investigations
• Document Type:
  Text
• Genre:
  Conference Publications ; Case Report
• Place as Subject:
  Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  TCRC - Twin Cities Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-24
• NIOSHTIC Number:
  nn:10001679
• NTIS Accession Number:
  PB-205501
• Citation:
  NTIS: PB 205 501; :1-24
• Federal Fiscal Year:
  1971
• Peer Reviewed:
  False
• Source Full Name:
  NTIS: PB 205 501
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:205b554a079d60214c1638bb049c0ebb33aefd87403f556c3a7ce26ad939613b28b51c20e057e524e68ee1badd73e89c55bb16a4d1cbd853e219fb6855614cf1
• Download URL:
  https://stacks.cdc.gov/view/cdc/237646/cdc_237646_DS1.pdf
• File Type:
  [PDF - 8.64 MB ]