Roof Failure in Longwall Headgates – Causes, Risks, and Prevention

Details

• Personal Author:
  Esterhuizen E ; Su D ; Trackemas J ; Van Dyke M ; Zhang P
• Description:
  Roof failures in the longwall headgates mostly occur outby the T-junction area within the front abutment pressure zone. The roof in this area could fail in the form of cutters, sagging, or collapse. Although front abutment pressure, high horizontal stress, and adverse roof geology are primary risk factors that cause headgate roof failure, other mining factors such as panel orientation, pillar sizes, roof support and operational parameters also contribute to the instability of a headgate. To prevent headgate failure during longwall mining, it is important to understand the causes of roof falls, risk factors, and effective risk mitigation measures. This study is based on the headgate roof support experience in a longwall mine in the Pittsburgh seam. The occurrence of roof falls in two longwall panels and the geotechnical solutions are described in detail. Numerical modeling was conducted to investigate the effect of the longwall retreat direction on stress concentrations in the headgate. Causes and risks of roof falls in the longwall belt entry, and mitigation measures for roof-fall risks are discussed. Through diligent geologic reconnaissance, proper roof support design, and proactive risk management, roof falls in longwall headgates can be prevented. [Description provided by NIOSH]
• Subjects:
  Mining Occupational Health Safety
• Keywords:
  3D Coal Mines Coal Seams Environmental Stress Failure Analysis Geologic Models Geologic Strata Geotechnical Engineering Ground Control Ground Monitoring Ground Subsidence Horizontal Stress Longwall Mining Models Pillar Design Pillar Mechanics Rock Mechanics Roof Falls Roof Supports Roof Support Systems Structural Analysis Subsidence Three Dimensional Underground Mines

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• Series:
  Mining Publications
• Publisher:
  American Rock Mechanics Association (ARMA)
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  OSHA Region 10 ; OSHA Region 3 ; Pennsylvania ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PMRD - Pittsburgh Mining Research Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20053043
• Citation:
  52nd US Rock Mechanics/Geomechanics Symposium, June 17-20, 2018, Seattle, Washington. Alexandria, VA: American Rock Mechanics Association (ARMA), 2018 Jun; :ARMA 18-956
• Contact Point Address:
  Peter Zhang, Ground Control Branch, NIOSH, Pittsburgh Mining Research Division (PMRD), Pittsburgh, PA
• Federal Fiscal Year:
  2018
• NORA Priority Area:
  Mining
• Peer Reviewed:
  False
• Source Full Name:
  52nd US Rock Mechanics/Geomechanics Symposium, June 17-20, 2018, Seattle, Washington
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b8cef6ddee2e37d7eb4c805f1fe47fb20619dd33bbaddad83563b66d28b86dd14d6b8779b8327f75f824fd73f538925d6b9451b4bcbd9d5efa16aac122f91623
• Download URL:
  https://stacks.cdc.gov/view/cdc/227729/cdc_227729_DS1.pdf
• File Type:
  [PDF - 1.53 MB ]