A New Abutment Angle Equation for Deep Cover Coal Mines

Details

• Personal Author:
  Klemetti, Ted M. ; Tulu IB ; Tuncay D
• Description:
  The National Institute for Occupational Safety and Health (NIOSH) first developed the Analysis of Retreat Mining Pillar Stability (ARMPS) program to help the U.S. coal mining industry to design retreat room and pillar panels. Similar to other pillar design methodologies, ARMPS determines the adequacy of the design by comparing the estimated in situ and mining induced loads to the load bearing capacity of the pillars. ARMPS calculates magnitude of the in situ and mining induced loads by using geometrical computations and empirical rules. The program uses the "abutment angle" concept in calculating the magnitude of the mining induced loads on pillars adjacent to a gob. The value of the abutment angle for coal mines in the United States was derived by back analysis of field measurements, and ARMPS2010 engineering design criterion was derived from the statistical analysis of the databases of more than 640 retreat mining case histories from various U.S. coal mines. In this study, stress measurements from U.S. and Australian coal mines were back analyzed using the square decay stress distribution method, and the abutment angles are investigated. The results of the analyses indicated that for shallow mines with overburden depths of less than 200 m, empirical derivation of 21 degree abutment angle used in ARMPS2010 was supported by the case histories. However, at depths greater than 200 m, the abutment angle was found to be significantly less than 21 degrees. A new equation employing the overburden depth to panel width ratio was constructed for the calculation of abutment angle for deep cover cases. Finally, the new abutment angle equation was tested using 336 deep cover cases from the ARMPS2010 database. The new abutment angle equation was found to perform a good classification compared to using 21 degrees. It was also apparent that, for deep cover cases (deeper than 200 m), the barrier pillar stability factors were the governing parameters in classification of failed cases and the results can be considered an indicator for the importance of barrier pillars in deep cover retreat mines. [Description provided by NIOSH]
• Subjects:
  Database Engineering Geology Mining Occupational Health Safety
• Keywords:
  Analytical Models Coal Mines Databases Environmental Stress Geologic Models Geotechnical Engineering Ground Control Ground Stability Mathematical Models Models Monitoring Systems Pillar Design Pillar Mechanics Rock Mechanics Roof Supports Statistical Analysis Stress Underground Mines Underground Mining

  More +
• Series:
  Mining Publications
• Publisher:
  American Rock Mechanics Association (ARMA)
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  New York ; OSHA Region 2 ; OSHA Region 3 ; Pennsylvania ; West Virginia
• 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:20057678
• Citation:
  53rd US Rock Mechanics/Geomechanics Symposium, June 23-26, 2019, New York, New York. Alexandria, VA: American Rock Mechanics Association (ARMA), 2019 Jun; :ARMA 19-0325
• Federal Fiscal Year:
  2019
• NORA Priority Area:
  Mining
• Peer Reviewed:
  False
• Source Full Name:
  53rd US Rock Mechanics/Geomechanics Symposium, June 23-26, 2019, New York, New York
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f86ae7141ba8329ff5f520c3bfd2ca36b4691ce6d696b29cf65965ef84989648249d7d070571c797942408c63283dab53984851f8654028740e194c3eef062ae
• Download URL:
  https://stacks.cdc.gov/view/cdc/227923/cdc_227923_DS1.pdf
• File Type:
  [PDF - 589.17 KB ]