RE: News is outGenerally for Open Pit Mining a grade of .3% Cu equivalent is good but many mines are .6 or .7% CU equivalent. Therefore you have to mine considerably more tonnes which is more expensive. This means high volume throughput. say 50,000 plus tonnes per day. Other factors come into play as well:
You're looking at the whole deposit. The .55% CUeq cutoff of 209 million tonnes represents 3.3 billion pounds of copper equivalent at an average grade of .66% and a cutoff of .55%. By the time they get through that and move on to the lower grade stuff, the mine will have been paid for and the lower grade ore will be gravy.
The original news release stopped at a .35% CUeq cutoff and did not fully represent the amount of higher grade metal in this deposit. This news is huge and actually better clarifies the amount of higher grade ore in the deposit.