Board Thread:Suggestions forum/@comment-93.41.115.43-20180205183113/@comment-29773086-20180205184223

The mithril-coat of Bilbo was not made from resources sourced in Erebor. The mithril was mined in Khazad-dûm, and taken to Erebor. The only way that mithril can spawn in Erebor is as already crafted loot in the major structure itself, when added.