Unfortunately, I cannot comment, and I will not defend Barrick here. I have visited several Barrick sites around the world, including the one in Tanzania, and I can't say that people have committed illegal acts there, such as murder or the like. However, I doubt that the mining operation itself supervised or condoned such things. I would bet on it.
On the other hand, that is not to say that certain things did not happen. I don't know enough about it to say. I have been to mining operations where the situation was difficult. In the case of Barrick, there was a lot of artisanal activity going on above their mine. It's true that it was on their land, but I don't think it was Barrick's activities.