Is it not true that having a stock of open pit ore at a relatively lower g/t and a feed of higher g/t ore from underground mining has this effect? What I understood from DW was that these two sources of ore allow the company to adjust to rising / falling price of gold. THey could process more of the open pit bulk ore when prices are high, and that would be profitable, and when the price is lower, use more of the underground ore to ensure that the mine is always profitable.
SKELEG