If I can just get involved here the whole heavier core thing is a very folksy way of looking at things. As a geologist I can assure you that the percent nickel does not make a significant difference in the weight of the actual rocks. And the weight of the rocks is not what keeps companies from exploring deeper the problems with deep exploration arise when you factor in the cost of drilling at increasing depth due to the number of rods needed the types of rods the bending of the holes and the added man hours, so no its not because the rocks are too heavy to bother exploring for. And the whol there must be another 17M tons deeper is maybe true maybe it isn't deposits dont necessarily have deeper counter parts thats not how these systems work. Also just because something is high in sulphides until we understand the Ni tenors the weight added by increased sulphide may not even be an indication of what is high or low grade.