The miners are all dead, just like any prospects of Mithras being able to hold on to his title.

A great victory, %PCName. Mithras won't be able to recover from this. Once the word gets around to the Parliament of Bugs, his days are numbered. I will make sure of that. Don't worry about anyone finding out about your involvement in all of this. House Telvanni understands that might makes right, my dear, and after this, nobody will dare to question yours.

Has it been done?

The mine can't function without the workforce. I'll cut to the chase -- I want you to kill every single worker in the mine. Miners, guards and the rest alike. Mithras already has issues finding people willing to work at the mine and once we demonstrate that he's unable to protect his flock, we'll make sure that nobody will want to work for him ever again.