Where do elves get metal?

[Alcuin]

There are certainly bridges built by the Noldor. The stone bridge over the Narog built at the behest of Turin in Nargothrond is one. But the construction techniques of the Noldor were unrivalled by any but the best of the Dwarves: Gondolin with its repurposed tunnel through the Encircling Mountains, an echo of the Gate of the Noldor that Turgon left behind; Finrod’s fortress at Tol Sirion; Tirion upon Túna in Eldamar; Fëanor’s fortress in the north of Valinor, where he kept the Silmarilli and his father Finwë was murdered by Morgoth; not to mention the various other fortresses of the Noldor in Beleriand (of Maedhros at Himring, of Caranthir in Ered Luin, and so on). All were described as beautiful, strong, and enduring even under attack.

While the Dwarves of Khazad-dûm no doubt assisted in some of the works of Eregion, I think we should imagine that most of the construction in that land was the handiwork of the Noldor. As Legolas reported when the Company of the Ring entered Hollin,

[T]he Elves of this land were of a race strange to us of the silvan folk, and the trees and the grass do not now remember them; only I hear the stones lament them: deep they delved us, fair they wrought us, high they builded us; but they are gone. They are gone. They sought the Havens long ago.

The stones of Hollin at least recalled the deep delving of the Noldor. Most of the survivors of Eregion lived with Elrond in Rivendell until the end of the Third Age: it was they who reforged Narsil into Andúril.

Zigûr, I did not know you were writing a dissertation on Tolkien. Congratulations! Where? might you tell us when its defense is scheduled? and may we read it when it is published?