FMG update, page-15

Here are some other important facts:
Fact 1 - TAS has NOT announced that there WON’T be any further drilling. See the latest Q.
Fact 2 - Fortescue may earn a 51% beneficial interest by sole funding A$4 million plus GST on exploration expenditure within a 3 year period.
Fact 3 - Fortescue must expend a minimum of A$1 million before it can withdraw. If Fortescue withdraws before expending A$4 million it will earn no interest.
Fact 4 - After earning a 51% interest, Fortescue may at its election, increase its Joint Venture interest to 80% by sole funding a further A$7 million plus GST on exploration expenditure within a further 5 year period. If Fortescue withdraws before expending the further A$7 million its interest will remain at 51%.

I seriously doubt FMG will walk away at this stage.