@Jimmy Shelter's answer stated (regarding Orodruin, post-One-Ring-making):
Potential evidence of a future use of it was for making the battering ram Grond in the War of the Ring.
LOTR Wikia contains uncited statement, instead pointing to Barad-dûr:
Grond was forged in Mordor by Smithies of Barad-dûr during the final years of the Third Age, specifically for use by the army besieging the city of Minas Tirith in Gondor. It shared its name, in homage, with the "Hammer of the Underworld," a great mace wielded by Morgoth, Sauron's former master.
Is there canon support for either of those theories, especially Orodruin one?
In LOTR itself, I found no mention of location beyond "the dark smithies of Mordor":
Great engines crawled across the field; and in the midst was a huge ram, great as a forest-tree a hundred feet in length, swinging on mighty chains. Long had it been forging in the dark smithies of Mordor, and its hideous head, founded of black steel, was shaped in the likeness of a ravening wolf; on it spells of ruin lay. Grond they named it, in memory of the Hammer of the Underworld of old. Great beasts drew it, Orcs surrounded it, and behind walked mountain-trolls to wield it. (The Return of the King)