Board Thread:Suggestions forum/@comment-25012056-20160725221323/@comment-26298013-20160727222138

Just to point this out: The ONLY place mithril can be found in Middle Earth is in the vein below Zirakzigil, where the Dwarves mined it. No other place was ever found to have Mithril. It COULD appear throughout the rest of the Misties, but it's been all but mined out in Moria. To dig deeper would lead to encounters with the Nameless Things.

The Dwarves found the hiding place of the Balrog (The tunnels/cave system under Moria, which were connected to the Endless Stair. The Balrog knew much about these tunnels, clearly because he hid down there. The Dwarves dug into the cavern system [And then made Durin's Tower at the top of the Endless Stair {What a walk!}] and then encountered the Balrog, all while chasing mithril). They've cleared the useable parts of the vein.

The White Mountains should NOT have mithril, as Moria is specifically stated to have been the last place where mithril could be found in Middle-Earth. Same with Erebor.