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Mining Product: CMRR - Coal Mine Roof Rating

Original creation date: February 1995

CMRR (Coal Mine Roof Rating) is software for estimating the relative inherent strength of coal mine roof.

The Coal Mine Roof Rating is a roof classification system that was first introduced to the mining community in 1994. It filled a longstanding need to quantify geologic description of coal measure rocks into an engineering value which could be used for mining design purposes. Rocks which form the roof of coal mines can vary widely and quickly in composition, extent, and defects. This results in an equally broad range of rock properties which can substantially affect the ability of the rock mass to form a stable mine roof. The CMRR was designed to evaluate the properties of the coal mine roof rock mass which contribute to its´ weakness and convert them into a relative strength rating from 0-100. These properties include the cohesion and frequency of discontinuities like bedding, slips, shears, and joints, UCS, and moisture sensitivity. With simple laboratory and field tests and observation, the CMRR can be calculated by technical and operating personnel with a minimum of training.

Originally designed to be used with underground exposures, the CMRR can also be calculated from core. The CMRR has found a wide range of applications. These include: integration into ALPS and ALTS, the chain pillar design program for longwall gateroads in both the U.S. and Australia; in the assessment of the suitability of extended cuts; roof bolt selection; roof fall evaluations; input for numerical models; and in tailgate support guidelines.

The download file is a self-extracting executable which will automatically run a setup program.

Release notes for version 2.1.03 (August 2013):

  • Minor bug fixes
  • Fixed operating system compatibility issues
  • User interface improvements

Release notes for version 2.1.01 (October 2012):

  • Recompiled with new libraries
  • 16/32 bit controls have been replaced with 32/64 bit controls
  • User interface improvements
  • Program installer has been updated with more options and better checks for older installations
  • Various bug fixes
  • Tested for better functioning under Windows 7

Authors: NIOSH

Audience: Mine operators

Software (Windows) - August 2013

  • Download

Version: 2.1.03

Pittsburgh, PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 2013 Aug