It's actually ""Expert Judgment on Markers to Deter Inadvertent Human Intrusion into the Waste Isolation Pilot Plant" which, at least the parts of the 400+ page report I've read, are just that expert opinions boiled down to fairly lay terms without judgment. There are others more recent, but I've only got access to them behind a pay barrier.
That's the one, yes.
Also, forget mining, think Hiram Bingham or even Joe Public out for a stroll into glowy death.
Assuming the place is properly designed  (if it's not, that's
the problem to solve), strolling into glowy death just Won't Happen(TM). Exposing the contents of a nuclear waste repository requires either a determined effort or a cataclysmic event - the latter of which brings me back to "mankind will have bigger problems"...
(Incidentally, this post was written while crunching radionuclide data, heh)
 I haven't looked at the designs for that particular plant, but I'm assuming something akin to Äspö HRL