I came across a dude in 1996 that had the receipts. His LES statements. Did 13 years underground and swore about 50% of the Freeway system was paralleled underground. Was an orphan and started working at 14. Fully retired (medical I think, for being fucking nuts) at 28. E-7 pay. Had pics of the rig he worked on.
I really tripped out on that one. Couldn't trip him up on his story but I still have a hard time believing it.