Your 10% or less improvement is based on only a $0.25 improvement to the $3.25 price used.
What if copper is at $6.50 a year from now?  We have nearly a whole year where we have been above $4, so in a year when copper is at that new assumed level, LT consensus should adjust pretty quickly... maybe by over a buck to $4.25 - $4.50...

That would make a huge difference to NPV, way over 50% increase imo