RE: Question about El TenThe grade at Colihues is around 0.25% or roughly 2.5X higher than fresh tailings.
The difference is mostly because of improved recovery technology in the last couple of decades vs. earlier decades.
Over time, technology does enhance recoveries. But early technologies are obviously not very efficient. We have progressed to a point where technologies have gone as far as it can. After all, at this time, the key to recoveries is the time the ore is in a ball mill. It is the steel balls that do the grinding.
New mills built today would barely negligibly better recoveries than those build 15 years earlier.
The advantage ARG has is that it just doesn't make sense for the mammoth El Teniente complex to take extra time to get that extra 1% or 2%. As the tailings are sent down the tailings launder, the tumbling effect helps liberate copper and molybdenum. As well, ARG has a different process specifically designed to extract low grade material (i.e., fish ladder system).
I wouldn't worry about improving recoveries at El Tentiente hurting ARG. That would take 20 years if it actually happened. ARg would have made tons of money and we'll be cashed out long before this risk crops up.