I would not have thought he would get even that close... and I assumed it was the Mountains of Ered Luin, but now you've left me wondering if that's true. Ered Luin was what I was looking for anyway, the Sindarin name of the mountains that I thought Arvedui hid under, but since I may be wrong, it was a poor question!
Legate, I will say you got it because you first mentioned the old dwarf mines.
