OMG look at the size of the samples. 300-500grams. Bloody tiny samples. They could have been spot sampling tiny little crystalline Zn, Pb, Cu-bearing veins 1cm wide for all you know. What's wrong with 3-4kg samples? They'd be a lot more representative. Certainly nothing to get excited about.
Some channel sampling could have provided some widths to go with the grades to generate some useful data but they didn't bother.
I'd be digging up the historical data to get a feel for what's in the ground.
"A total of 88 geochem samples were
collected as random chips from
historically existing mining and
exploration workings. This includes from sites such as mine dumps, prospect pits & trenches, and adjacent mineralised outcrops.
Equipment used was predominately
hand-held hammer for the collection
of rock fragments. Samples were not necessarily representative of average grade of the area being sampled."