CREATE TABLE table_79971 ("Rank" FLOAT, "Mine" TEXT, "County" TEXT, "Operator" TEXT, "Source of copper" TEXT, "2012 Cu Production  ( lbs ) " FLOAT)

Which operator has a rank of 7?
SELECT "Operator" FROM table_79971 WHERE "Rank" = '7'
SELECT "Operator" FROM "table_79971" WHERE "Rank" = '7'