Time Dependent Roof Deterioration at a Central Ohio Coal Mine

Details

• Personal Author:
  Klemetti, Ted M. ; Molinda G ; Oyler D
• Description:
  Roof deterioration in weak moisture-sensitive rock leads to roof falls in coal mines. An observation site was set up in intake air at an underground coal mine in central Ohio to evaluate the time-dependent deterioration of moisture-sensitive roof rock. By periodically collecting and weighing the rock falling from the roof, the National Institute for Occupational Safety and Health (NIOSH) was able to quantify the deterioration of the moisture-sensitive shale roof. The measurements showed that more roof rock is falling in the dry winter months. Movements in an intersection were monitored in order to determine if deformation correlated with seasonal changes in temperature and humidity. The rate of intersection roof-to-floor convergence was found to be cyclical and related to seasonal changes, with more convergence during the months of April through September. At the study site intersection, the roof beam did not show deflection indicating movement most likely due to mine floor deformation. The bolt load also increased in the warmer months before shedding load, possibly due to rock failure. Temperature and relative humidity sensors, placed in holes in the roof show that mine air does not mix with the air in the holes. Consistent saturation levels of relative humidity were measured in the holes and it appears that high levels of moisture may have migrated into the bolt holes from roof shales. A roof sealant applied to a portion of the test roof appears to be preserving the roof and reducing the amount of rock fall into the entry, while the screened area virtually eliminated rock falling from the roof. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Humidity Mining Occupational Exposure Occupational Health Risk Assessment Safety Safety Management Temperature Workplace

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• Keywords:
  Coal-miners Coal-mining Coal-workers Ground-control Ground-stability Injuries Mine-shafts Mining-industry Occupational-hazards Quantitative-analysis Relative-humidity Risk-analysis Rock-falls Rock-mechanics Room-and-pillar-mining Safety-measures Safety-practices Temperature-effects Temperature-measurement Time-weighted-average-exposure Underground-mining Work-areas Work-environment Workplace-studies

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• Series:
  Mining Publications
• ISBN:
  9780978938338
• Publisher:
  West Virginia University
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  Ohio ; OSHA Region 3 ; OSHA Region 5 ; Pennsylvania ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRL - Pittsburgh Research Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  248-255
• NIOSHTIC Number:
  nn:20035811
• Citation:
  Proceedings of the 28th International Conference on Ground Control in Mining, July 28-30, 2009, Morgantown, West Virginia. Peng SS, Barczak T, Mark C, Tadolini S, Finfinger G, Heasley K, Luo Y, eds. Morgantown, WV: West Virginia University, 2009 Jul; :248-255
• Editor(s):
  Peng SS; Barczak T; Mark C; Tadolini S; Finfinger G; Heasley K; Luo Y
• Federal Fiscal Year:
  2009
• NORA Priority Area:
  Mining
• Peer Reviewed:
  False
• Source Full Name:
  Proceedings of the 28th International Conference on Ground Control in Mining, July 28-30, 2009, Morgantown, West Virginia
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0167959c695179f6505d293b4b4e5160700ab3ff86b38409323527989cd0a579ae2487838387ad77df3e0f2a23779b636d3be8edb57bbe703e6536804eb080bb
• Download URL:
  https://stacks.cdc.gov/view/cdc/227117/cdc_227117_DS1.pdf
• File Type:
  [PDF - 2.02 MB ]