The Savage River Iron Ore Mine, located in northwest Tasmania, was opened in 1968 to produce iron ore pellets from a magnetite orebody. Over the years four pits have been developed; South Centre Pit, Centre Pit, South Lens and North Pit. On the western walls of Centre Pit and North Pit flexural toppling failures have restricted overall slope angles to 37o. This paper discusses the geology, history and stability analyses of these toppling failures. The computer software programme UDEC has been successfully used to model excavation history, groundwater depressurisation and slope movements. The model is now being used to predict the future behaviour of the slopes to assist in mine planning.
The Savage River Iron Ore Mine, located in northwest Tasmania (refer to Figure 1), was opened in 1968 to produce iron ore pellets from the magnetite orebody. The magnetite is crushed at the mine and then sent via an 85km long slurry pipeline to Port Latta on the northwest coast for processing into hematite pellets. The original owners shut down operations in 1996 but in 1997 Australian Bulk Minerals (ABM) recommenced mining after relocating the crusher and installing a 1.3km conveyor. Over the years four pits have been developed; South Centre Pit, Centre Pit, South Lens and North Pit. The mine has had a history of flexural toppling failures in Centre Pit and North Pit that have restricted a major portion of the western walls to overall slope angles of 37o, with vertical slope heights in the order of 150m. This paper discusses the history of the toppling and the recent use of Itasca's (2000) UDEC computer programme to model the phenomena, i.e to back analyse previous failures. Detailed geology, excavation histories and dewatering aspects have successfully been incorporated into the UDEC model.