Compiled by the U.S. Dept of Health and Human Services, CDC/NIOSH Office of Mine Safety and Health Research, the 2007 proceedings of the International Workshop on Rock Mass Classification in Underground Mining contain 16 invited papers from nine countries, reflecting the international depth and breadth of current practice. Rock mass classification is widely used throughout the underground mining industry-in both coal and hard-rock mines. It is used in all stages of the mining process, from site characterization to production operations. The goal of the International Workshop on Rock Mass Classification in Underground Mining was to provide a forum for leading practitioners of rock mass classification to come together and share their methods and experiences with the technique. Applications in both hard-rock and coal mining are well represented.Content: Front Matter Unit of Measure Abbreviations Used in This Report Table of Contents Abstract1. Rock Mass Characterization for Excavations in Mining and Civil Engineering2. Mechanized Excavability Rating for Hard-Rock Mining3. Rock Mass Characterization of Primary Copper Ore for Caving at the EL Teniente Mine, Chile4. Stope Design Considerations Using Rock Mass Classification Tools at the Xstrata Zinc George Fisher Mine5. An Integrated Approach to Support Design in Underground Coal Mines6. A Rock Mass Rating Scheme for Clastic Sediments Based on Geophysical Logs7. Practical Experiences with Application of the Coal Mine Roof Rating (CMRR) in Australian Coal Mines8. Use of the Mining Rock Mass Rating (MRMR) Classification: Industry Experience9. Classification-Based Probabilistic Design of Ground Support10. The Geological Strength Index (GSI): A Characterization Tool for Assessing Engineering Properties for Rock Masses11. Development and Application of the Coal Mine Roof Rating (CMRR)12. Problems with Rock Classification for Empirical and Numerical Design13. Weak Rock Mass Design for Underground Mining Operations14. Application of the Q-System to Australian Underground Metal Mines15. Rock Mass Classification in German Hard-Coal Mining: Standards and Application16. Numerical Modeling Procedures for Practical Coal Mine Design