Valta's stone sense tells her that the way forward is through a rune-warded gate in the Darkspawn Warrens. The gate can only be opened with Ancient Gears.
Find 3 scorched ancient gears scattered around the area near the gate.
Locations: Next to the gate. In the room opposite the gate. By some rubble at the left side a down the hall.
Once the gears are installed, a note appears. Pull the lever to open the door.