RE:new to goldstart with their website.
typical mining op is 1g/t some are more some are less than that.
so if you look at roxgold's drill results so I think they're at 15g/t - what this means is simple - you're moving less dirt, more grams/ounces and cheaper to run the operation overall.
590 is probably one of the lowest number I've seen for AISC. Its a takeover target because of all the above I mentioned even if gold falls below 1200.