NIOSHTIC-2 Publications Search
The coal mine roof rating (CMRR) - a decade of experience.
Int J Coal Geol 2005 Oct; 64(1-2):85-103
The Coal Mine Roof Rating (CMRR) was developed 10 years ago to fill the gap between geologic characterization and engineering design. It combines many years of geologic studies in underground coal mines with worldwide experience with rock mass classification systems. Like other classification systems, the CMRR begins with the premise that the structural competence of mine roof rock is determined mainly by the discontinuities that weaken the rock fabric. However, the CMRR is specifically designed for bedded coal measure rock. Since its introduction, the CMRR has been incorporated into many aspects of mine planning, including longwall pillar design, roof support selection, feasibility studies, and extended-cut evaluation. It has also become international, with involvement in mine designs and funded research projects in the Republic of South Africa, Canada, and Australia. This paper discusses the sources used in developing the CMRR, describes the CMRR data collection and calculation procedures, and presents a number of practical mining applications in which the CMRR has played a prominent role.
Ground-control; Ground-stability; Mining-industry; Coal-mining; Underground-mining; Safety-research; Injuries; Hazards; Geology; Rock-falls; Underground-miners; Coal-miners; Longwall-mining
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Issue of Publication
Research Tools and Approaches: Control Technology and Personal Protective Equipment
International Journal of Coal Geology
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division