There is high grade gold starting right at the surface. The grades appear well within a very profitable open pit mine to start. The deeper stuff could be mined later by shaft mining, but I suspect that most of the soil on the Tesoro is mineralized and can be processed economically.
Exeter Resources is a good company to compare the grades and how profitable their mining will be. They have a low grade deposit and I beleive their highest ever gold sample only assayed 3g/t. Yet they figure they have over 20 million ounces of gold in a copper gold deposit only about one 12th the size of the old Tesoro.