Hydrogeological risk assessment in the Elatsite copper mine, Central Bulgaria

A strategy for a safe slope design is needed to mitigate the risk of a significant landslide initiation in the Elatsite open-pit mine in Central Bulgaria. This strategy should be based on detailed information about the water dynamics and the interplay of hydrology with various factors, such as the mountain geomorphology, engineering infrastructure, rock types and the distribution of rock anisotropies, which conspire for the overall degradation of the pit walls. In this work, an integrated risk-assessment approach is demonstrated that combines various layers of information superimposed in such a way as to delineate domains of the pit’s surface that are most vulnerable to mechanical degradation due to surface or percolating waters. The main result of the study is a map of the water-initiated risk that combines 12 separate maps for 12 studied classification parameters. For each domain, the risk is expressed by numerical values. This map is used for decision-making about the choice of the slope angle, position of engineering facilities in the pit and location of the waste rock depots etch.