Take the Inventor's Disk to the Inventor's Library Console inside the Inventor's Library.
Norgannon's shell is within our reach, <name>. Take the inventor's disk into the library's interior. There should be a console there that you can activate with the disk. I imagine Mimir stored more there than just Norgannon's shell. There are probably enough schematics stored there to keep Ironforge's engineers occupied for years!
Anyway, use the disk to recover the shell. Hopefully, Mimir hasn't decided to put any more obstacles in our way.
Also, you get: 3 70
The console appears to have an opening for the inventor's disk.
<You insert the disk into the console. Suddenly, lights on its surface illuminate and a mechanical voice speaks.>
Inventor's disk authenticated. Welcome back, Keeper Mimir.
Upon completion of this quest you will gain: