I found this very interesting when you look at the amount of expenditure and what it involves to mine this deposit. One of the most astonishing, among several others, is the fact that they intend to take several years of removing waste rock 350 meters deep to just get at the deposit!

This should tell you the extremes which miners will go through to get at a deposit.

http://www.mining.com/2012/06/13/bhps-eye-watering-olympic-dam-expansion-bulked-up-again/?utm_source=digest-en-mining-120613&utm_medium=email&utm_campaign=digest