"...and Rio Tinto ignored Hay Mtn...?

What? 

The Resolution project began when an explorationist got it in his mind that there could well be more copper in Superior, AZ at depth below the old Magma Mine.  Theory gave way to strong evidence, and BHP, world's second larget miner took over.  The more they drilled and discovered, the more they found this was too big for any one company, so Rio Tinto came into the story. 

Locally it is understood the economic mineralization extends 20-30 to the SSW, so the pit described in the article is but a small part of what is likely to come out of the area.

You are are not talking "blind target" here, though it was just that when private money made the discovery attactive to BHP.

The advantage Hay Mountain MAY have, should it prove viable to exploit, is that mineralization MAY be at and near the surface.  Drilling first, then the big boys MAY express interest.

By the way, I've climbed/bushwhacked around that area.  Picture no. 1 is of Apache Leap, which got it's name from an unproven report by a Mormon Battalion volunteer circa 1847.  Even if the report is true about Indian women and children leaping to their deaths to avoid capture, there is no evidence that it was at this location other than unsubstantiated reports of human bones littering the bottom of the cliff face long, long ago.  150 years later and Apache Leap is sacred ground when mining wants to come back to the area.  Strange world.