It's best if you take this quest first among the five tasks that Krak Flamewhip will demand of you. Then while running around to do the other quests, be sure to hold your "Alt" key and click on any ore box. You should gather at least 8 this way. In the end, the quest does a good job of pointing you to remaining ore boxes that have not been opened. There are more than ten ore boxes around, so finding your quota should pose little problem. After you collect 10, speak to Tharn to hand them over, then to Krak to get your reward.