We should expect the center to have higher grades. It is large as in 500 meters wide. Circular is what a halo of copper looks like and is relater to a root zone of high grade. The periphery metals indicates a seperate deposit ie deposit number 4. While smaller than the main zone the clear definition suggests the root is intact. That's what they have at Red Chris. In fact, a comparison of the two (periphery results) looks a whole lot alike. While they are not chemically identical they do share a common finger print.