Ann: Rio Tinto Devoncourt Project Farm-in Agreement, page-44

I would agree with this interpretation of Rio Tinto's thinking, their exploration mandate would be to find another Ernest Henry, and the obvious geophysical targets tested and the drill spacings and results would have led them to the point where they think its unlikely that an Ernest Henry size footprint is out there under cover, or at least at shallow depth. So a decision could be justified to JV out the ground on the assumption that the JV partner might find something like an Osborne or a Starra style orebody, or alternatively find nothing. If they do happen to jag something that is going to be another Ernest Henry or a Olympic Dam, then Rio Tinto will have the time and ability of spend/renegotiate/buy their way in.

I think for a company like CNB they would be looking to leverage off the existing Rio drilling, and also pay attention to the outcroppping or sub-cropping ground in the eastern part of the JV, where it's unlikely that Rio did a lot of work, and its also easier and cheaper to do exploration when its not concealed by 100-200m of Cambrian Limestone cover.