According to wikipedia, Rosemont is expected to earn $6.9B over the course of its predicted 21 year life span. Hudbay bought Augusta (who owned the rights) out for $555M. So if JB is correct, or even close to correct on his estimation (and hopefully he's being conservative), then we are in for a pretty nice payday.

https://business.financialpost.com/commodities/mining/augusta-resource-corp-agrees-to-hudbay-minerals-inc-sweetened-takeover-offer

Also, the history on Rosemont is pretty interesting (on wikipedia). It seems that the ground had been gone over several times and changed hands numerous times before things started happening. So Hay Mountain may be more similar to Rosemont than JB stated.