After you complete "The Troll's bounty" you will receive a quest from Brandon, who tells you that Lawrence realized the adverse effects of and he still sent the miners to the mines.
You can now go to Lawrence or to Nadia, who lost her husband in the mines and start a conversation about Brandon. If you go to Lawrence first, he will try to bribe you, so that you do not tell anyone. If you refuse the offer, your reputation will go down Even if you accept the bribe, you will be able to go to Nadia and tell her the truth about the mine manager. Still, she is going to need a strong proof of that. In the mines, you can find the "Mining Office's Letter"(you need to remember to collect it before you complete "Investigating the Mines"). With the letter in your hand, go to her and show it to her. She will run to Lawrence to confront him.
He will want to bribe her, to prevent her from telling the truth to the people and, you will be able to choose again. You can tell her to take the money, or not to. If you go for the latter, she will dash out and start shouting all over the place, and the manager will have to answer to the people.
Another decision to take appears here. You can allow the crowds to lynch the manager, or to let him go. If you decide on the latter, you will find his body in Northern Cyseal.