Resource or Waste?—Sensor-based Classification of Excavation Material in the NNATT Project

Excavation material constitutes the largest mineral waste stream while simultaneously offering considerable potential as a primary and/or secondary raw material in the construction sector. This contribution outlines the key material characteristics, regulatory framework, and practical utilization challenges. Excavation materials from two tunnel projects serve as case studies to illustrate how chemical-mineralogical characterization combined with Artificial Intelligence-based sensor classification can generate site-specific utilization strategies. This approach is implemented in a pilot plant with online-classification on a continuously operating conveyor belt. The results demonstrate that systematic integration of excavation material into the circular economy is technically feasible and economically viable, provided that classification procedures, approval processes and project planning are aligned.