The stability of a raise bore is often assessed using the rock mass classification system published by McCracken and Stacey as a modification of the Q system. Often the assessment is done using a spreadsheet to manipulate geotechnical log(s) of boreholes. This paper discusses the inherent difficulties with this approach. Recent work by others to provide guidelines to the classification system is discussed. A recent example of the design and raise bore performance at Macraes Gold Mine, New Zealand is presented. A key issue is that a visual assessment of the drill core and/or core photographs is necessary to ground-truth' the classification._x000D_
FORMAL CITATION:Bertuzzi, R and Wallis, J, 2008. Rock mass classification is only part of the answer to assess raise boring, in Proceedings Tenth Underground Operators' Conference 2008, pp 191-198 (The Australasian Institute of Mining and Metallurgy: Melbourne).