Slope geometry design as a means for controlling rockfalls in quarries

This paper presents a rockfall control method for rock quarries, based on benched rock slope design and catch-bench width control. The aim is to prevent rockfalls in quarries, which cause a significant number of accidents and even fatalities. Whereas catch ditches have traditionally been used as the main rockfall control method for roads and highways, benches carved into slopes are typically used in open-pit mining. In the road engineering field a simple empirical technique, recently reviewed and updated, has long been in use that is capable of ensuring slope designs that prevent falling rocks from reaching the travelled area of a road. Such techniques are lacking in the quarrying field, however, and this work is an attempt to develop a method similar to those developed for road engineering, but specifically adapted to quarry slope geometries. Using statistically significant data on the parameters affecting falling block trajectories, obtained from empirical data and from a back-analysis performed using a rockfall modelling code, we estimated geometries for quarry slopes that would prevent falling rocks from reaching work areas. This information was compiled and presented in the form of charts (for 2-bench, 5-bench and 8-bench slopes) that enable the user to design rockfall-safe slopes.