UESP on X: "Did You Know: The mine with the most iron ore in Skyrim is Halted Stream Camp? Conveniently, this mine also has a spellbook that teaches you the transmute spell,
Where is the best place to mine iron ore in Skyrim on PC? - Quora
Morthal's Ghastly Mine - The Elder Scrolls V: Skyrim Special Edition - GameFront