CORRECTION:

Where I said, "...and noting that ore is 5-7 thousasnd feet deep at Superior, AZ, where BHP & Rio Tinto are investing billions",

should read, "...and noting that ore BEGINS AT 5-7 thousasnd feet deep at Superior, AZ, where BHP & Rio Tinto are investing billions."

This is just to make clear the comparisons between having ore grade material at surface, as compared to the deep mining required nearby (where grades are around 1.5 percent copper, but very, very deep).