Integration of Russian and foreign rock mass stability classifications for validation of mine support systems

Abstract

This research aims to develop a methodology of selecting and validating support system designs for different purpose roadways by means of synthesizing the rock mass quality index Q and the stability categories which are in application in mines in Russia. The existing approaches to rock mass quality evaluation based on different combinations of complementary classification criteria are reviewed and generalized. It is found that the stability categories in use in Russian mines comply with the Q-index, which enables their flexible adaptation to specific features of a deposit and allows revealing of average mining conditions for different mines. The multi-factor rock mass quality rating and classification made it possible to justify mine designs per different categories. On this basis, the safe shapes and cross-section sizes are determined for the face entries for the prevalent geological conditions of ore mining under equicomponent (hydrostatic) stress state. The analysis and generalization of actual data from operating mines in the ore provinces in Yakutia, Russian Far East, Krasnoyarsk Krai and Eastern Kazakhstan allowed correlating the maximum permissible widths and cross-section shapes of roadways, as well as the roadway purpose and the rock mass quality by the Q-system by Barton. The revealed patterns of rock mass stability effect on the roadway roof span size made it possible to define rockbolting design variables for the face entries of operating mines in rock masses characterized by the widely ranging Q-index. The implementation of the integrated approach to rock mass stability estimation can improve reliability of the pre-project and project design solutions aimed to enhance safety and efficiency of roadways in different geological and geomechanical conditions of mineral mining.