Hmm,

I think the difference is that they have already found traces of Gold on their land.

Generally most exploration companies are at stage 1, go out and find something.
I think here, they are at stage 2, they have found something, and need funds to further detail exactly how much has is actually there.

So regardless, as long as the traces are correct, the promise of Gold is 100%. It is more of a question of exactly "how much".

-Ukyo