My dictionary sais ore is a natural substance from which metal...

My dictionary sais ore is a natural substance from which metal can be profitably extracted. The material from the surface down is going to be stockpiled as it is considered that copper can be profitably extracted. I thought I might draw your attention and you would trip over the 1 for none ratio, but that is what it was meant to do : emphasise that the strip ratio at this stage of the mine will indeed be very low. Overburden on the other hand has no ore of value in it. I almost feel as if I am teaching little kids in grade 3!