Classification of Khoemacau (Zone 5) Carbon Rich Rockmass Using Q and Rmr Systems to Recommend Support for Ore Drives

The Khoemacau project is situated on the Kalahari copper belt which stretches over 1000km from northeast Botswana into southwest Namibia and consists of deformed Meta volcanic and sedimentary rocks. High-grade copper and silver mineralization is dominantly related to shearing, folding and tensional failure along and close to the Ngwako Pan and D’Kar contact. Disseminated and hydrothermal vein-hosted sulfide mineralization. Older CAR unit rocks seemed to deteriorate and the disking of the siltstones begins to break apart also showing signs of high shearing. This was a concern as it showed that this rock unit may pose problems during mining as it may lead to tunnel collapses and unstable conditions. So, in this research paper the quality of this rock mass will be assessed using the RMR and Q Classification method. The Carbon rich rock mass of Zone 5 was classified, and it is found to be inferior quality rock. The recommended support for RMR classification suggested systematic bolts 4-5m long, spaced 1-1.5m in crown and walls with wire mesh combined with Shotcrete 100-150mm in crown and 100mm sides and steel sets light ribs spaced 1.5m where required while that of Q-system suggested systematic bolting, (and unreinforced shotcrete, 4-10cm). The observations suggest that the use of two or more classification systems in design and rock engineering, will lead to better and more accurate results in terms of adequately classifying the rock mass and providing sufficient support. This is proved by the more intense support of (steel sets light ribs spaced 1.5m where required) that was suggested by using the RMR classification. In conclusion the empirical methods show that extraction will be feasible with the selected mining method (Sub-level open stoping).