A Study of the Ground Control Effects of Mining Longwall Faces into Open or Backfilled Entries

Details

• Personal Author:
  Dolinar, Dennis R. ; Frith RC ; Mark C ; Oyler, David C.
• Description:
  Unusual circumstances may require that a longwall retreat into or through a previously driven room. The operation can be completed successfully, but there have been a number of spectacular failures. To help determine what factors contribute to such failures, a comprehensive international database of 131 case histories has been compiled. The cases include six failures where major rock falls occurred in front of the shields, and seven even more serious failures involving major overburden weighting. The case studies suggest two types of room failure mechanism. The first is a roof fall type failure caused by loading of the immediate roof at the face as the fender or remnant longwall panel narrows. The second is an overburden weighting type failure caused by the inability of the roof to bridge the recovery room and face area, and affecting rock well above the immediate roof. The data indicate that the roof fall type of failure is less likely when intensive roof reinforcement (bolts, cables and trusses) is employed together with higher-capacity shields. The overburden weighting failures, in contrast, occurred when the roof was weak and little standing support was used. Weighting failures were not greatly affected by the density of roof reinforcement. In one of the overburden weighting cases, in a Pittsburgh coalbed mine, stress cell, convergence, bolt load and extensometer data have been used to analyze the failure in detail. [Description provided by NIOSH]
• Subjects:
  Case Reports Coal Coal Mining Engineering Mining Occupational Health Safety
• Keywords:
  Author Keywords: Coal Mining Case-studies Coal-mining Engineering-controls Ground Control Longwall Mine-shafts Mine-workers Miners Mining-equipment Mining-industry Recovery Room Rock-falls Weight-factors Weight-measurement

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• Series:
  Mining Publications
• ISSN:
  0960-3182
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRL - Pittsburgh Research Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  137-168
• Volume:
  19
• Issue:
  2
• NIOSHTIC Number:
  nn:20021827
• Citation:
  Geotech Geol Eng 2001 Jan; 19(2):137-168
• Contact Point Address:
  Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, Pitssburgh Research Laboratory P.O. Box 18070, 626 Cochrans Mill Road, Pittsburgh PA, USA
• Federal Fiscal Year:
  2001
• Peer Reviewed:
  True
• Source Full Name:
  Geotechnical and Geological Engineering
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:fc66e03c4b63b84067ed43f68e48ebf1c8c31d1025b46447aa41d405385a91ed17afb53841d0d6e40d31c63b2c55ef1ba53640b98bc6dd02d627c289f4aa917a
• Download URL:
  https://stacks.cdc.gov/view/cdc/220512/cdc_220512_DS1.pdf
• File Type:
  [PDF - 323.93 KB ]