what is the cost of production of aluminium, copper, iron per tonne?

Answer 1

Southern Copper Corp reported (Nov06) the following: Cash cost per pound of copper produced and purchased for 9 months ending Sept 30, 2006 was $0. 275 http://biz.yahoo.com/e/061103/pcu10-q.html

Some information on production cost can be found through these links:
Copper: http://www.ame.com.au/guest/cu/cost.htm
Aluminum: http://www.ame.com.au/guest/al/cost.htm
Iron: http://www.ame.com.au/guest/fe/strategic.htm

New aluminum technologies: http://www.tms.org/pubs/journals/JOM/9905/Welch-9905.html

Answer 2

It is a difficult question, because all of them are very energy intensive. So it depends on what value one gives to the energy.

For example, coal and oil based plants have been closed because the cost of the energy is higher than the price of the metal.

Hydroelectric energy is a better bet, as long as the electricity cannot otherwise be sold locally.

Aluminum is generally produced in areas where there is excess hydroelectric energy and the "cost" of this electricity is considered as free.