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New developments with the coal mine roof rating.
Mark-C; Molinda-GM; Barton-TM
Proceedings of the 21st International Conference on Ground Control in Mining, August 6-8, 2002, Morgantown, West Virginia. Peng SS, Mark C, Khair AW, Heasley KA, eds., Morgantown, WV: West Virginia University, 2002 Aug; :294-301
The Coal Mine Roof Rating (CMRR) was first presented at this conference 9 years ago. 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 truly international, with involvement in mine designs and funded research projects in the Republic of South Africa, Canada, and Australia. The purpose of this paper is to bring the mining community up to date with recent improvements and applications of the CMRR. The most important new development is a streamlined process for determining the CMRR from exploratory drill core. Only three types of information are now required: (1) fracture spacing (or rock quality designation), (2) uniaxial compressive strength (or axial point load testing), and (3) diametral point load testing. The moisture sensitivity adjustment has also been changed, and new research has related the immersion test to slake durability. Most recently, the CMRR has been implemented in a computer program, which can be obtained from NIOSH free of charge. The program facilitates calculation of the CMRR from either underground or drill core data. Values from many locations can be saved in a single file, and an interface with AutoCAD allows CMRR contour plots to be integrated into mine planning.
Ground-control; Ground-stability; Geology; Rock-falls; Longwall-mining; Coal-mining; Underground-mining; Computer-software; Hazards; Injuries; Safety-research
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Peng-SS; Mark-C; Khair-AW; Heasley-KA
Research Tools and Approaches: Control Technology and Personal Protective Equipment
Proceedings of the 21st International Conference on Ground Control in Mining, August 6-8, 2002, Morgantown, West Virginia
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division