In the middle level of the main shaft you'll find a storeroom with a guard called Ulbert. Offer him a beer and he'll explain what the chests contain. He mentions something about a digger named Aleph having the key. You can't pick these chests, so you'll have to get the key.
Go back to the smaller side cave and ask Aleph for the key (it costs you 30 Ore). Now go back to Ulbert and lure him away. Once he's safely out of sight empty the chests. One contains some spell scrolls (Fireball, Firebolt, etc.) while the other has some Ore and other misc. items.
Go down to where Ian is and you'll see Ulbert who is rather upset. You get a final 75 EXP for tricking him, but only if you go down and talk to him.
Right beside him is Ian; if you're doing the Test of Faith ask him for the list now.