(a) the processing by the taxpayer ofi. ore, other than iron ore or tar sands ore, all or substantially all of which is from a mineral resource owned by the taxpayer to any stage that is not beyond the prime metal stage or its equivalent,
ii. iron ore all or substantially all of which is from a mineral resource owned by the taxpayer to any stage that is not beyond the pellet stage or its equivalent,
iii. tar sands ore all or substantially all of which is from a mineral resource owned by the taxpayer to any stage that is not beyond the crude oil stage or its equivalent, or
iv. material extracted by a well, all or substantially all of which is from a deposit of bituminous sands or oil shales owned by the taxpayer, to any stage that is not beyond the crude oil stage or its equivalent;