Improving Hard Rock Pillar Design by Including Rock Mass Classification and Failure Mechanisms

Details

• Personal Author:
  Esterhuizen, Gabriel S. ; Oke J
• Description:
  The limitations of the current pillar strength formulas, empirical design charts, and continuum numerical modelling is that these methods do not consider discontinuity driven failure mechanisms (i.e. jointing at critical angles). However, strength formulas have been very effective within the coal industry because they have a better representation of the rock mass strength (sample sizes > standard sizes) and large databases of case histories providing sufficient statistical representation of both stable and failed cases. Additionally, coal pillars generally have larger width to height ratio (>1) which decreases the influence of through going structure. This is opposite for hard rock mine where the width to height ratio is generally <2 and as small as 0.3, where structure can have a major influence on the stability. Additionally, the small size of hard rock unconfined compressive strength samples does not represent the strength of the rock mass, without additional considerations. Therefore, an improved strength formula is proposed that includes the influences of rock mass strength and discontinuities. This proposed strength formula, and its associated factors (length effect, and discontinuity dip and properties) can be used to create site specific empirical design charts. [Description provided by NIOSH]
• Subjects:
  Body Height Mining Occupational Health Safety
• Keywords:
  Analytical Models Compressive Strength Design Criteria Design Standards Failure Analysis Geologic Models Hard Rock Mines Height Factors Industrial Design Mining Industry Models Pillar Design Pillar Mechanics Rock Mechanics Structural Analysis Structural Design Structural Failure

  More +
• Series:
  Mining Publications
• Publisher:
  American Rock Mechanics Association (ARMA)
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  California ; OSHA Region 3 ; OSHA Region 9 ; Pennsylvania
• 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:20050168
• Citation:
  51st US Rock Mechanics/Geomechanics Symposium, June 25-28, 2017, San Francisco, California. Alexandria, VA: American Rock Mechanics Association (ARMA), paper no. ARMA 17-009, 2017 Jun; :ARMA-2017-009
• Contact Point Address:
  Jeffrey Oke, MDEng Inc., Kingston, Ontario, Canada
• Federal Fiscal Year:
  2017
• NORA Priority Area:
  Mining
• Peer Reviewed:
  False
• Source Full Name:
  51st US Rock Mechanics/Geomechanics Symposium, June 25-28, 2017, San Francisco, California
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:901a4b7f2b503fac8352270495d10272d291b7441284d6907b9fa20172b355a4825885c565c52473234fe1b8350194455fcb82939ff24c8ce1e33d9e4128d6df
• Download URL:
  https://stacks.cdc.gov/view/cdc/228475/cdc_228475_DS1.pdf
• File Type:
  [PDF - 872.03 KB ]