Obtain the Worldbreaker Schematics from Blackrock Orcs in the Blackrock Quarry.
Looks like we'll soon have another obstacle in our way: that ridiculously large tank that they have pointed at the Dark Portal. The Iron Worldbreaker, I think they call it.
If I had some documentation on how it might work, then I might be able to figure out how to shut it down. Maybe some o' those machinists and laborers have some documentation on how it works?