C1 is a site cost, so comparable to EMH's numbers. C3 includes...

C1 is a site cost, so comparable to EMH's numbers.
C3 includes corporate and royalties and all sorts of other crap which makes it not applicable for comparison, particularly on only 3ktpa.

On a Byproduct basis, the cost is $0, after crediting the sale of potash, silica, tantalite etc.

On a Co-product basis the cost is $4,500, The Potash Cost is $150, the tantalite cost is $20/lb etc etc, But you have to add in all the revenues from all the co-products, which is too hard for us to do, so we should be using the By-Product basis. But they both give the same bottom line, so it doesn't really matter.