Tectonic structures and commercial compartments in active quarrying: a case history from northern Italy

By studying a quarried site exposed in the Ligurian Alps (northern Italy), this work aims to assess the impact of the tectonic structures on the exploitable rock volume characteristics/properties and, more in general, on the three-dimensional quarry architecture for its future exploitation. A field-based, multidisciplinary dataset has been integrated within a 3D geological model performed in a Geographical Information System (GIS) environment. The spatial distribution, geometry, and internal fabric of the main tectonic structures (mainly represented by faults and fracture networks) have been recognised as responsible for a structural compartmentalisation within the study area. In situ geomechanical measurements (uniaxial strength by using a Schmidt hammer) have been compared with distribution of the tectonic structures. A simulation of the influence of the tectonic structures on the rock mechanical behaviour has been performed in GIS. We conclude that occurrence of tectonic structures determines a first order degree in geodiversity at quarried sites, influencing both intrinsic (lithology and petrography) and secondary (mechanical) properties of the excavated rock volume. Consequently, understanding and reconstructing the deformation style and intensity of the tectonic setting constitute a further geological exploration criterion for assessing strategy of rock excavation and exploitation. The identification of tectonic structures is relevant to face frequently documented problems in active quarrying, such as mass movement and slope failure, reduced rock-mass quality, or non-exploitable quarry domains.