I don't get the 2.52 year concept?, and isn't the concentrate at 5.8% or there about when its ready for shipping?
As per @mushroom one 15 million tonnes of recoverable resource processed at a rate of 1.6 million tonnes per annum = 9.375 years, and of course there will be delays and many other marvellous things that will jump up within that time, so IMO 9.5 years is reasonable.
GXY Price at posting:
43.5¢ Sentiment: Buy Disclosure: Held