This paper explores possibilities to quantify key parameters for rock mass  excavatability in drilling, blasting and cutting by TBMs and roadheaders. Although rock mechanical properties play a key role, geological parameters are rarely fully included in most projects. In some cases, the influence of geological features on rock fragmentation can be more significant than varying rock properties. Geological difficulties can have a high impact on
the economics of an underground construction project, especially when the chosen excavation system turns out to be unsuitable for the conditions encountered. Thus it can be argued that the geological and petrological
characteristics of the rock mass should be evaluated with the same degree of effort as that for the geotechnical prognosis.