Ann: Lake Torrens IOCG Project - Drilling Update, page-30

Olympic dam has billions of dollars of infrastructure... electricity, water, railroads, onsite processing plants.
Its been expanded and redeveloped several times and more recently embarked on cost saving programs. Big investments can easily turn from big profits to big losses depending on how the market for particular minerals moves over a decade or so. Probably that's why Rio eventually turned it down. Its not that the deposits aren't there, they knew all that in 2013. Its the development costs and associated risks. Maybe FMG believes its a good risk?

Its not going to be an easy decision unless perhaps the new drill holes also turn out to be good as well.
Maybe that's one reason why GS took the $4.8m cold hard cash.