NIOSHTIC-2 No. 20021814


Using the Coal Mine Roof Rating (CMRR) to Assess Roof Stability in U.S. Coal Mines

2001

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The stability of any underground opening is, in large part, a function of the strength of the rock mass which surrounds it. The Coal Mine Roof Rating (CMRR) has been developed to quantify the defects in the rock mass and compile a strength value which can be used for engineering design. The CMRR has been applied to a number of ground stability problems, including chain pillar design, roof bolt selection, hazard assessment, intersection design, and numerical modeling. The CMRR procedure and some of these applications are described in this paper. The CMRR will soon be available in a Visual Basic computer program, allowing easy integration into exploration programs and standard roof fall assessments.

Author(s):Molinda-GM, Mark-C, Debasis-D
Reference:J Mines Met Fuels (India) 2001 Aug-Sep:314-321

   utcmr (PDF, 1209 KB)


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Page last updated: September 17, 2008
Content Source: National Institute for Occupational Safety and Health (NIOSH) Mining Division