The Mines

Below and beyond the common & residential areas in the Dwarven Catacombs are labyrinthine tunnels that are completely unlit. These are constantly expanded by Dwarves as they search for valuable metals and minerals. The passages range from narrow slits to huge vaults. The area is punctuated with numerous elevator shafts; some are heavily used, many are abandoned.
Small railcars are used along main tunnels to carry products of the mines to the Miners' Exchange in Undertown, and thence to the Enclave as a whole.
It is dangerous to venture into the Mines without a skilled dwarven guide. Frequent natural hazards include pits, rockfalls, gas pockets, and underground streams. Dangerous cavern-dwelling creatures are sometimes found.
Intelligent monsters have not been found in the Mines within living memory, though some cavers repeat old tales of blind Goblins or fish-men. Stories like these are also found in The Magical Library.