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|The Coal Mine Root Rating (CMRR) was first presented at this Conference nine years ago. Since Its Introduction, the CMRR has been incorporated into many aspects of mine planning. including longwall pillar design, rout support selection, feasibility studies. and extended cut evaluation. It has also become truly international, with involvement in mine designs and funded research projects iii South Africa. Canada. and Australia. The purpose of this paper is to bring the minim community Up to date with recent improvements and applications of the CMRR. The must important new development is a streamlined process for determining the CMRR from exploratory drill core. Just three types of information are Jaw required: Fracture spacing (or RQD) Uniaxial compressive strength for axial Point Load Testing) 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 firm either underground or drill core data. Values from ninny locations can he saved in a single file. and an interface with Autocad allows CMRR contour plots to he integrated 11110 mine planning.|
Additional chapters/articles from the SME-ICGCM book Proceedings 21st International Conference on Ground Control in Mining
|Pre-Driven Experimental Longwall Recovery Room Under Weak Ro||Longwall Mining-Induced Abutment Loads and Their Impacts on||Influence of Structural Stress Concentration and Structural||The NIOSH Shield Hydraulics Inspection and Evaluation of Leg||Study on Top-Coal Loss and the Optimum Drawing Interval of L||Stress Measurements for Safety Decisions in Longwall Coal||Re-Use of Rectangular Bolted Roadways in a Cover Depth > 100||Numerical Modeling of the Gob Loading Mechanism in Longwall||Deep Cover Pillar Extraction in the U.S. Coalfields||Evaluation of Pillar Recovery in Southern West Virginia||A Case History Investigation of Two Coal Bumps in the Southe||A Linear Coal Pillar Strength Formula for South African Coal||Anchorage Pull Testing for Fully Grouted Roof Bolts||Comparison of Some Aspects of Bolting Mechanisms Between Ful||Eclipse System Improves Resin Anchored Rebar Bolting||Design Considerations for Tensioned Bolts||Field Testing of the Fully Grouted Thrust Tensioned Bolts||Improvement in Pre-Tensioning of Strand Bolts in Australian||The Introduction of Roof Bolting to U.S. Underground Coal Mi||Support of Coal Mines in the United Kingdom||The Use of NDT Methods to Determine the Condition of Rockbol||Rockbolted Support of Retreat Longwall Gateroads at 1000m De||Roof Screening: Best Practices and Roof Bolting Machines||Numerical and Physical Modeling as Planning Tools for Rockbo||Stone Mine Design in Highly Fractured Rock||The Importance of Underground Stone Mine Roof Geology||Utilization of Ground-Penetrating Radar to Determine Roof Co||An Examination of the Loyalhanna Limestone's Structural||Highwall Stability in an Open Pit Stone Operation||Overview of Safety Considerations with Highwall Mining Opera||Highwall Monitoring to Combat Rockfall Accidents at Opencast||Seepage and Reinforcement Behavior of Grouting Into Slaking-||Floor Heave in Shallow Room-and-Pillar Mining||Analysis of a Stability Problem in an Underground Coal Mine||Comparison of Acoustic Emission and Stress Measurement Resul||Acoustic Scanner Analysis of Borehole Breakout to Define the||Estimating Rock Strengths Using Drilling Parameters During R||New developments with the coal mine roof rating||Application of geotechnical and geophysical parameters to im||Development of a Risk Rating System for Use in Underground C||Empirical and analytical design of large openings at a propo||Shear Mechanism for Mining-Induced Fractures Applied to Rock||Evaluating Techniques for Monitoring Rock Falls and Slope St||Developments in Sealant Support Systems for Ground Control||Stability Control of Clusters of Deep Openings Around Shaft||The Use of Pneumatic Stowing in Germany Considering Subsiden||A 3-D Semi-Analytical Method for Subsidence Prediction and S||Theory and Technology of Mining Subsidence Control by Grouti||Surface Subsidence Due to the Combined Effects of Undergroun|