Newcastle Chapter

Rock Slope Design in Layered Rocks: Some Precautionary Tales

John Simmons

The coal mining industry requires slope designs in layered coal measures and other rocks on a routine basis. The scale of these slopes far exceeds that of slopes in comparable materials for civil purposes, yet the effort involved in design of mine slopes is comparatively minor. There are many reasons for these apparent discrepancies but the common thread is an accepted level of risk management within a defined context.

This presentation outlines the geotechnical considerations involved in coal mine rock slope design. Some highly successful designs and some disastrous failures are described. There is a third category of experience where hazards are tolerated and managed under conditions of widespread concern. In all circumstances there are important precautionary tales for geotechnical practitioners that may be summarised as follows: adequate knowledge of geological conditions, adequate knowledge of groundwater conditions, and adequate understanding of the effects of time and weather.

Speaker biography

John Simmons is a consulting geotechnical engineer with experience in the open cut coal mining industry in eastern Australia and Indonesia since 1990. He trained at the University of Queensland and the University of Alberta and his experience ranges from soft soils and insitu testing to embankment dams, engineering geological mapping of natural slope instabilities, and analysis and design of soil and rock slopes. Currently he is based on the Sunshine Coast and is a conjoint fellow of the University of Newcastle where he is jointly supervising two PhD projects related to geotechnical design of coal mine waste dumps.

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