The dwarves did have a suspiciously big amount of mithril for the reforging of the gate of Minas Tirith, so chances are high they were pretty quick to return to Khazad-Dūm. Whether the mine, that Elves found uncanny long before the Balrog and the orcs (see the definition of Khazad-Dūm in the Silmarillion) could ever be onjectively unflawed and utterly beautiful, is another matter.
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