Aurum Vale is not part of the main story and is a side quest given by the NPC Nedrick Ironheart in Vesper Bay (Western Thanalan). The quest is given at level 47 and the max level for this dungeon is 49. Any player above 49 will be level synced to 49 upon entry to the dungeon. The dungeon is located in Coerthas Central Highlands.
The Aurum Vale was in version 1.0 and shares similar mechanics as the boss fights are the same creatures. Coincounter is probably the most challenging encounter in here, with mechanics which force you to run in front of the boss when he uses a certain move and then back behind afterwards.