There has been increased focus in Australia on large diameter raise boring for ventilation shafts and orepass excavation in good quality, brittle, highly stressed rock. As mining in many parts of Australia progresses to deeper levels, more vertical openings are being excavated in highly stressed ground conditions. However, whilst shafts have been successfully raise bored in highly stressed rock, it is often at a significantly increased risk of loss or damage to inhole equipment. It is important for both mine owners and contractors to have an appreciation of these risks at the planning and tendering phases of raise boring contracts._x000D_
This paper provides an understanding of the risks associated with large diameter raise boring and a review of methods to predict failure in highly stressed rock._x000D_
FORMAL CITATION:O'Toole, D and Sidea, D, 2005. Recent developments in Australian shaft excavation practice - raise bored shafts in highly stressed rock, in Proceedings Ninth Underground Operators' Conference 2005, pp 29-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).