Located inside of Understone Keep in Markarth, it is the home to Nimhe, a giant Frostbite Spider. This excavation site also contains Alethius's Notes in Nimhe's lair, which begins the quest "The Lost Expedition."
To reach the Nchuand-Zel Excavation Site, enter Understone Keep and immediately go to the left. Climb a small hill and continue going straight. Climb the set of four stairs, which lead to a larger flight of stairs. At the top of the second set of stairs is the entrance to the excavation site. The adept-locked door can be picked if the key is not in the Dragonborn's possession.
To obtain the key, speak with Calcelmo, who can be found around the arcane enchanter and alchemy lab to the left upon entering Understone Keep. He will task the Dragonborn with killing Nimhe. If the Dragonborn accepts, Calcelmo will hand over the key to the excavation site.
When Nimhe has been killed, the Dragonborn gains access to the Dwemer Museum.
- A Dwemer chest is straight ahead from the entrance, hidden behind the rocks at the end of the passageway. It can only be reached by jumping to the top of the rock pile.
- A Dwemer chest is in the room with two stone pillars just before the webs. It is reached by climbing the wooden scaffolding. Then using the rocks on the scaffolding reach the rocks sticking out of the wall. From there, follow a ledge leads to a fallen stone block. The chest is on the other side of the fallen block. Note that getting over this block to the chest is quite difficult to do by simply jumping, being that the block is so large and so close to a piece of the wall that sticks out. The Dragonborn can use all three words of the Whirlwind Sprint shout to get to the opposite side of the ledge, and from there they can easily get to the chest.
- Four iron ore veins in an open room that resembles a mine. The first vein is on the right-hand side. The second vein is at the end of the walkway to the left, beside three barrels. The third is on the floor as the corner is rounded. The last vein is on the wall to the right, just before the first spider web.
- One corundum ore vein on the left side of the tunnel after the spiders but before Nimhe.