In Situ Estimation of Roof Rock Strength Using Sonic Logging

Details

• Personal Author:
  Mark C ; Molinda, Gregory M. ; Oyler, David C.
• Description:
  Sonic travel time logging of exploration boreholes is routinely used in Australia to obtain estimates of coal mine roof rock strength. Because sonic velocity logs are relatively inexpensive and easy to obtain during exploration, the technique has provided Australian underground coal mines with an abundance of rock strength data for use in all aspects of ground control design. However, the technique depends upon reliable correlations between the uniaxial compressive strength (UCS) and the sonic velocity. This paper describes research recently conducted by NIOSH aimed at developing a correlation for use by the U.S. mining industry. From two coreholes in Illinois, two from Pennsylvania, and one each from Colorado, western Kentucky and southern West Virginia, sonic velocity logs were compared with UCS values derived from Point Load tests for a broad range of coal measure rock types. For the entire data set, the relationship between UCS and sonic travel time is expressed by an exponential equation relating the UCS in psi to the travel time of the P-wave in mu s/ft. The coefficient of determination or R-squared for this equation is 0.72, indicating that a relatively high reliability can be achieved with this technique. The strength estimates obtained from the correlation equation may be used to help design roof support systems. The paper also addresses the steps that are necessary to ensure that high-quality sonic logs are obtained for use in estimating UCS. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Engineering Mining Occupational Health Quality Control Safety Workplace
• Keywords:
  Analytical-processes Author Keywords: Sonic Log CMRR Coal-mining Coal-workers Coal Mine Roof Rating Coal Mining Control-technology Corehole Engineering-controls Geophysical Logging Geophysical Strata Rating (GSR) Mathematical-models Mine-shafts Mining-industry Qualitative-analysis Quality-standards Room-and-pillar-mining Structural-analysis Underground-mining Uniaxial Compressive Strength Work-environment

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• Series:
  Mining Publications
• ISSN:
  0166-5162
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OMSHR - Office of Mine Safety and Health Research
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  484-490
• Volume:
  84
• Issue:
  4
• NIOSHTIC Number:
  nn:20037712
• Citation:
  Int J Coal Geol 2010 Sep; 84(4):484-490
• Email:
  dbo1@cdc.gov
• Federal Fiscal Year:
  2010
• Peer Reviewed:
  True
• Source Full Name:
  International Journal of Coal Geology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:39c84586618bcd88e5496aaafda759918f3563e55507c9e79bcf3882c571fd02c4ec8db2564457b2635935bb30b8985aeb75665dcf6bb45fe5415203eb100051
• Download URL:
  https://stacks.cdc.gov/view/cdc/227260/cdc_227260_DS1.pdf
• File Type:
  [PDF - 1.19 MB ]