RE:Underground Block Cave MiningVery interesting and informative. And the porphyryr we have is inline with or slightly above the grades they're showing in the examples of the Chiqui UG and Palabora's UG.
I especially liked this part "Codelco has decided to pursue a block cave approach. Among other objectives, Codelco also expects Chuquicamata underground production costs to come in between the lowest and second-lowest quartiles among world copper producers".
I would imagine that Freeport is just as efficient as Codelco, so we could potentially have a cheaper than average mine for what was originally dismissed as uneconomical.