In the early 1980s, 2 by 7.5m diameter TBM tunnels were driven from the Donkin-Morien peninsula in Nova Scotia to access the Harbour Seam. Support design was based on the application of the Hoek Brown failure criterion and the early use of finite element analyses. The mining project was abandoned and the tunnels allowed to flood. Monitoring data from the tunnel was used as a case study in the development of the concepts of brittle rock (Martin et al, 1999). In 2007, the tunnels were pumped out as part of a feasibility study into the reintroduction of longwall mining. There is a good match between observations of the collapse zones in the roof and sides of the tunnel and a simple elastic analysis using the brittle parameters. The brittle analyses form the basis of the resupport program being installed.
