Interesting to look at, they started off with the oxide only and look at the allin cost $500 , wow.
Then got into the refractory stuff year 3,4,5 still profiting, but not to the extent they would like no doubt.
Last 2 years though seems they have gotten a handle on recoveries using an ultra fine grind, but 2015 was a huge blow out year in terms of costs for them, 2016 production is way down grade is up, they may being more selective high grading to keep costs down.
Overall they are making it work, but you need a minimum 3Moz high grade deposit, having 300koz of $500 gold to kick things off helps as well.
How close exactly is the Tongon plant do you know? if it's within trucking distance? if so that changes everything.