Ann: Wodger Drilling Intersects Multiple Zones of Copper Sulphide, page-50

They certainly get zapped with the portable XRF to determine the (rough) grade of the rock. The samples are then sent to the lab for assay.

The chips are logged by the geologist. The geologist logs the rock type, sulphides visible, and veining.

The geologist then (in theory) plots it on a cross section (and/or in 3D) and tries to make sense of the XRF results and geology and, keeping in mind the rig costs $350/hr on standby, tries to determine what's going on and where to drill next.

No structural info, beyond qualitative stuff like "this is strongly sheared" etc. it's just a spoon full of wet gravel for each metre.

So the geologists are probably saying "In the zone from X to Y metres we see 10-20% quartz-carbonate veining, possibly chalcocite/bornite of 0.5-1%, in basalts and sediments. This matches up with this zone in the other hole. It's maybe going this way or that way"