I had a troll mine an entire copper ore deposit for me today. It was kind of tricky getting him to line up his shots with his log to hit the ore. I'd roll out of the way and he'd still miss the ore some times. Took all most 10 minutes to get him to get all the ore mined for me which was about the same amount of time it would have taken me to mine it myself but I didn't have to repair my pick this way.