Travel for 30 minutes down each tunnel, starting with the one just Left of the just searched tunnel. Return to the mining camp after each search.
30 minutes down each tunnel is simply more tunnel, sadly. The network must be pretty damned big.
You returned to the mining camp afterwards.
Check the mining camp for anything that can be used to trap the artifact room.
There's ores that could be used for deadfall traps, but otherwise nothing more useful than that.
Lazanarius searches the area immediately outside the cave for ways to camouflage the entrance.
you could use the rocks that the zombies broke to fortify the entrance with, that would count. Right?
Ire searches for an exit to the surface as its one of the more important things to find, they also search the mining camp before hand.
You searched the mining camp to find it mostly abandoned, there's food and alcohol supplies here as well as ore, but not much else.
You travel an hour down each tunnel, still no exit to the surface to be found. Where the hell are you?
Noose hisses and slithers back into a corner to regenerate his minions.
You rest for some time, your Minion soon regenerates, stepping out of where you had called them from. Your wounds all healed thanks to your fellow friendly Knight Pan.
See if we can't harvest knowledge on ores from the shards of dwarven soul.
You poke around the souls and harvested some memories, discarding the useless ones, you kept the one about smelting and smiting as well as the ore that they've been mining. Useful!
You now recognize the ore to be mostly coal, but also some iron, copper and tin in the mix.
This realistically put you not that deep in the deeper deep. Otherwise there would've been at least Mithril.