I think you are both coming to the same conclusion that we have more value now then in 2013 and both are directly linked to the exchange rate.

Teck did not only use $3.00 US for QB2.  They also had a scenario at $3.25 & $3.50.

I don't recall the source, but I was under the impression that they would use a higher price for copper (e.g. $3.08 US)

I'm under the impression that Copper Fox is also trying hard to get the long term consensus gold price revised due to the recent upward movement, which could be a reason for the delays.

MoneyK