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Assessing Coal Mine Roof Stability Through Roof Fall Analysis

Public Domain
File Language:
English


Details

  • Personal Author:
  • Corporate Authors:
    National Institute for Occupational Safety and Health. Pittsburgh Research Laboratory
  • Description:
    In 1999, 2,087 unplanned roof falls were reported from 841 mines. Nearly 55% of all mines reported at least one roof fall, and nearly 17% of the mines reported five or more falls. In order to investigate the variables that contribute to roof falls, the National Institute for Occupational Safety and Health (NIOSH) compiled a national database of roof performance from 37 coal mines. Geotechnical factors and their effect on roof fall rates were compiled from over 1,500 miles of drivage. The factor that is the best predictor of roof fall rate is the Coal Mine Roof Rating (CMRR). For a low CMRR (#30), almost all cases have high roof fall rates. Conversely, high roof fall rates are rare for strong roof rocks (CMRR $ 60). Roof fall rates were also higher in deeper mines, probably because of greater stresses. Intersections were much more likely to fall than roadways, and four-way intersections were more prone to fall than three-way intersections. In a controlled comparison of the effect of increasing bolt length on roof fall rates, it was found that longer bolts reduced the roof fall rates in 11 of 13 cases. A relationship between the roof fall rate, the intersection span, and the CMRR was also found. Finally, a systematic method for tracking roof performance and geotechnical variables was demonstrated.
  • Subjects:
  • Source:
    Proceedings: new technology for coal mine roof support. Mark C, Dolinar DR, Tuchman RJ, Barczak TM, Signer SP, Wopat PF, eds. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2000-151; (IC 9453), 2000 Oct; :99-109
  • Document Type:
    Text
  • Genre:
    Conference Publications
  • CIO:
    National Institute for Occupational Safety and Health (NIOSH)
  • NIOSHTIC Number:
    nn:20000880
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:54a57b0e79b5f75869c8552890dceaccf250d6650e9832773db9e5e211daa2e672e38b1f55e68dcca63032f0d42f43dc65ec49aeeb0aa56983932a4ebfc214cd
  • Download URL:
  • File Type:
    Filetype[PDF - 653.39 KB ]
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