Abstract
Reliable rock mass characterization is needed to design safer and more economical roof support systems of coal mines. Coal Mine Roof Rating (CMRR) index is a commonly used method by roof control engineers to characterize immediate rock units above the underground coal mines. This index ranges from 0 to 100 and was developed by studying the performance of the roofs in the Appalachian coal fields, which have typically strong roof units. Application of CMRR for weak and moisture sensitive rocks such as shale roof units in the Illinois Basin may misrepresent the rock mass. In this study, the rock laboratory test results are conducted to characterize the moisture sensitivity, axial and diametral strengths of roof units. The CMRR indexes and designed roof systems in a coal mine located in Illinois Basin will be presented. A sensitivity analysis is also performed to identify the most influential CMRR rock mass characterization parameters in weak rocks. This study shows while CMRR rock mass characterization has many advantages, it should be cautiously used for roof support design in weak and moisture sensitive roof conditions.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
