I have the same problem
I did a quest that ended with the miners killing lawrence when nadia revealed to them that lawrence had knowingly sent their fellow miners to mine tenebrium and die from the rot
but now
I have the goblins head from the prison cell in the mines but no one to give the head to
I want to clear all the quests in the game but have hit a snag here.
I love how non-linear the game is but don't like when I can't complete a quest because of something I did out of order many saves ago.