Old school geological skills combine with modern technology and a bit innovative/ lateral thinking.
Dip and strike measurements of a nearby exposure means that we can be fairly confident of the fracture orientations of the rock core.
But what if the rock is folded between the exposure and the borehole? (Not uncommon). This could mean that fractures that we think are dipping into the slope of the proposed cutting are now dipping out, with potentially disastrous consequences!
Downhole geophysics would confirm the fracture orientation, but so now do dual-camera endoscopes (readily available for around £50 from Amazon (and other retailers)).
Some old school geological skills combined with modern technology and a bit innovative/ lateral thinking mean that the logging of the rock cores for a proposed excavation are now much more useful and more confident recommendations can be provided.