ROFRAQ: A statistics-based empirical method for assessing accident risk from rockfalls in quarries

This paper describes an empirical method, called Rockfall Risk Assessment for Quarries (ROFRAQ), which assesses the risk associated with rockfalls in quarries. The method is based on a probabilistic approach that assumes that an accident occurs as a consequence of a sequence of events. This method has been applied to slopes in a number of quarries, and has proved useful in detecting troublesome slopes on the basis of empirical evidence. Thus far, it has been applied to around 100 slopes from various quarries of different rocks. These results show satisfactory agreement with results for empirical methods applied in the civil engineering field to highways and roads. The authors describe a case study of a granite aggregate quarry that highlights a number of issues in relation to practical application of the method.