Influence of highwall mining progression on web and barrier pillar stability

Details

• Personal Author:
  Harris KW ; Perry KA ; Raffaldi MJ
• Description:
  Highwall miners have been widely used to extract additional coal reserves from existing surface operations, particularly on contour operations in the Appalachian coalfields. Using a continuous miner cutting head, coal may be extracted from significant depths (such as 150 m), leaving behind an array of web and barrier pillars with the purpose of maintaining highwall stability. This method inherently involves elevated risks to both equipment and personnel due to proximity to and increased exposure time near highwalls. As a result, modern operations should actively design web and barrier pillars to maximize extraction while providing adequate stability. The ARMPS-HWM software, an empirical-based program created for the design of web and barrier pillars at highwall mining operations, is one such approach. The calculated stability factor is compared with empirically established guidelines produced from examining case histories. The ARMPS-HWM program is a handy tool for initial design, but understanding the site's structurally significant geologic features and geomechanical behavior is important and may potentially increase extraction. We created a two-dimensional numerical model using FLAC 3D and calibrated it to ensure pillar strength, closely following the Mark-Bieniawski formula for a typical range of pillar geometries and overburden properties. The development of pillar stresses along a highwall panel was then numerically investigated as mining progressed, and the stress distribution between barrier pillars was found to be asymmetric, which can result in an over-design of the closeout web pillars if tributary area loading is assumed. Finally, the importance of adequate barrier pillar stability is highlighted. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Environment Geology Mining Occupational Health Safety
• Keywords:
  Coal-mining Computer-software Highwall-mining Mining-industry Rock-falls Underground-mining
• ISSN:
  0026-5187
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Journal Article
• Place as Subject:
  Kentucky ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  59-67
• Volume:
  67
• Issue:
  3
• NIOSHTIC Number:
  nn:20047134
• Citation:
  Min Eng 2015 Mar; 67(3):59-67
• Federal Fiscal Year:
  2015
• Performing Organization:
  Uniiversity of Kentucky
• Peer Reviewed:
  True
• Source Full Name:
  Mining Engineering
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6e7f3b6fe48059977f2f01128c4adf53384ba22156827158b39e28e62e2f6cdde16b3b6ee909d806782d28786488458d18d406336c7ea7c528f6d37012f87a13
• Download URL:
  https://stacks.cdc.gov/view/cdc/202316/cdc_202316_DS1.pdf
• File Type:
  [PDF - 3.34 MB ]