[goldfinger]

Actually I think they may have tried to live secretly in lesser mines and mansions at the southern feet of the mountains away from the dragons who inhabited the Withered Heath, probably some of the mountains in the Northern fork, and I would assume some of the halls and mansions of the dwarves, because the dwarves were forced from their cities by the dragons. And their's also the goblins who invaded the mountains later on. They probably lived in the Western parts and possibly the central, and some may have been ruled by dragons for all we know.
Anyway, I think they lived rather secretly because if the dragons and goblins got wind of them they would have been all over the dwarves like flies on a animal carcass. Although the danger changed after the Battle of Five Armies, because over 3/4 of the Goblin warriors of the North were killed in the battle and there was peace for many years.

I do believe personally though that during the Fourth Age the dwarves drove away the dragons, and destroyed the goblins and took back their ancient homes in the Ered Mithrin. Because you see the mountains, I would think, still would have been rich with whatever was mined there back in the beginning when the dwarves first came there.