gbg vs ago

http://www.perthnow.com.au/business/atlas-iron-on-target-to-produce-77m-tonnes-of-iron-ore/story-e6frg2qc-1226547832412

I read in the above artical that atlas is set to produce 7.7 million tones pa now it has 3 mines online, now in the last gbg announcement they stated that they were on track to produce 8 million tonnes pa by April and this is out of 1 mine, atlas shares hit $1.89 on Tuesday so from an amateur investors point of view gbg is ridiculously cheap and has massive potential.

Also I know it's more expensive to produce magnetite but I would think 8 million tonnes pa of magnetite from 1 mine would be cheaper to produce than 7.7 million tonnes pa from 3 mines.

Just thought I'd put my 2 cents worth in.