Be a bit wary when discussion is all about grade - you need tonnes of ore as well, and ultimately the ounces in it. A lot of Victorian gold is coarse (we talk about it having a "nugget" effect), so if your drillhole goes through a coarse gold patch (remembering drillcore is only a few cm in diameter) you will get a fantastic assay. I have seen reefs where one drillhole got ounces per tonne, one that went through the same reef 5 m from the first drillhole got zero. It is the mean (average) grade of the ore and tonnes ot ore that determine if you can mine it.
But good luck to them.....