The Nucleation of Bedding Plane Thrusts on Geometrical Irregularities: Evidence from Oil Shales in an Ohio Coal Mine

Details

• Personal Author:
  Elizalde C ; Griffith WA
• Description:
  Oil shales form the roof and floor rocks of many coal mines in the Appalachian Basin. These mines offer outstanding 3D exposures of fresh rocks, presenting an excellent opportunity to directly observe pristine in situ natural fractures in shale. Small thrust faults are well exposed inside a coal mine in Carroll County, Ohio and predictably develop in areas where gradients of coal-shale contact are steepest, leading to roof rock instability in those areas. We test the hypothesis that sloping bedding-plane contacts serve as natural displacement discontinuities which augment the local stress state, causing localized secondary thrust fault development. Digital recreation of the primary bedding-plane discontinuity using exploration wells and in-mine survey data allowed 3D numerical-mechanical modeling of slip along bedding discontinuities and related stress perturbation. Coulomb stress change shows that shear failure is encouraged in areas in which thrust faults were mapped. This suggests that inherited non-planarity in bedding discontinuities influence the nucleation of thrust faults. Simulation results as constrained by the integrated field and modeling approach taken in this study will help better understand natural fracture distributions in oil shales. In particular, recognizing subsurface stress heterogeneities due to bedding topology can improve our predictive capabilities of underground structural hazards and can also aid in the identification of subseismic faults and fractures. Description provided by NIOSH
• Subjects:
  • Coal
  • Coal Mining
  • Mining
  • Occupational Health
  • Safety
• Keywords:
  • Topography
  • Underground mining
  • Underground construction
  • Mining engineering
  • Models
  • Rock mechanics
  • Ground stability
  • Coal mining
  • Simulation methods
  • Oil shale
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Ohio ; OSHA Region 5 ; OSHA Region 6 ; Texas
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1
• NIOSHTIC Number:
  nn:20053120
• Citation:
  2014 The Geological Society of America (GSA) Annual Meeting, October 19-22, 2014, Vancouver, British Columbia, Canada. Boulder, CO: The Geological Society of America (GSA), 2014 Oct; :1
• Contact Point Address:
  Ciel Elizalde, Earth and Environmental Sciences, University of Texas at Arlington, P.O. Box 19049, 500 Yates St. Geoscience Building Rm. 107, Arlington, TX 76019
• Email:
  ciel.elizalde@mavs.uta.edu
• Federal Fiscal Year:
  2015
• NORA Priority Area:
  Mining
• Performing Organization:
  University of Texas at Arlington
• Peer Reviewed:
  False
• Start Date:
  20121122
• Source Full Name:
  2014 The Geological Society of America (GSA) Annual Meeting, October 19-22, 2014, Vancouver, British Columbia, Canada
• End Date:
  20150831
• Download URL:
  https://stacks.cdc.gov/view/cdc/215946/cdc_215946_DS1.pdf
• File Type:
  [PDF - 143.14 KB]
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1aab7cf3c27606dd40a120865603f7474762d4fcbb62d72b2bb10d63d869d66b11190d95c3e7207d25d96c80bf52aa1ce145c2920cadcd4b58cfab9a8289e6cf