Blackrock Deeps Entrance. For the Prison section the boss is High Interrogator Gerstahn and the boss for the Upper section is the Emperor. Once inside your map changes and you should be able to see the entrance to Blackrock Depths.
Starts from Maxwort Uberglint at. The depths have many sections including a prison Shadowforge City a vast capital of the Dark Iron dwarves and the Grim Guzzler tavern. I also cannot unlock the Service Entrance from Burt Macklyn--even though it is checked as completed in my quest log.
However there are not two different portals so when you are queued up for either you will start out in the main entrance.
Another massive case solved just days. This is a guide on how to gain access to the dungeon Blackrock Depths this is a nice place to find transmog gear the only place that players can smelt Dark. It is accessed by a stair-lined shaft that requires one to swim through an underwater entrance. Blackrock Depths is the deepest part of Blackrock Mountain ruled by the Dark Iron dwarves who were led by Emperor Dagran ThaurissanSeveral minions of the Firelord Ragnaros also make their home in these lava-lined depths.