Horse - it's a question of what copper mineral is being mined, not what the head grade is.
Sooner later the chalcocite will run out. chalcocite gives the 50% con grade. when it does the mill will be processing chalcopyrite or maybe bornite ores, so be prepared for a con grade of 35% max.
i haven't seen anything that says they have chalcocite for the LOM? i could be wrong in my assumption here.
