Because someone posted earlier that you need a certain grade to do "economical" mining, let me give you an example of the largest, low-cost open-pit mine in Mexico:

Goldcorp´s Penasquito mine:

http://www.goldcorp.com/_resources/project_pdfs/Penq-dec-08-reserves.pdf

They have really large tonnage (1 million tonnes)

with an average grade of 0.456 gpt

for 17.369 M oz. gold !

So grade is NOT the only variable to determine ECONOMICAL mining.

Tonnage, open-pit or by-products can help.

And we are going for: tonnage, tonnage, tonnage.

FANTOMAS