Wear to the tools used for excavate the rock mass has a significant relevance for the cost and performance of tunnel drives in hard rock. This applies in particular to mechanised tunnelling processes, where the effect of wear is an important factor for system availability. At the moment, laboratory tests and derived abrasiveness indices like the Cerchar Abrasiveness Index (CAI) or the Rock Abrasivity Index (RAI) provide the basis for evaluation of tool wear. It should however be noted that such index values can only take into account influential factors on the scale of the intact rock. Influential factors on the scale of the rock mass, for example mixed‐face conditions, unstable face conditions, blockiness or the primary and secondary stress states at the face, can also be significant for the tool wear that is actually experienced. The possible consequences of such disadvantageous effects, which for example can cause catastrophic failure of tools, can represent many times the abrasiveness of the intact rock.