At low detection limits sample hygiene is critical. There's a...

At low detection limits sample hygiene is critical. There's a couple of possibilities in my opinion:

1) contamination of the first batch in the collection process, but more likely in the lab and likely during prep(not proven). This would be one of the worst scenarios as it means there potentially was never an anomaly.
2) sample sequence mixed, in the field or in the laboratory. I'm presuming that stats done on the infill area have therefore mistakenly been collected around the wrong samples. This would be a better outcome as the anomaly may still exist elsewhere in the grid. Though you maybe wouldn't see such a big variation in soil geochemistry in a relatively small area?
3) not worth considering the other possible conspiracy theories regarding some kind of deception. They're just too unlikely in my opinion.

I've only breezed in without looking at too much detail. I was watching the Durkin fiasco years ago but have a better opinion of current management.

Just my opinion and the company looks to have done everything right in terms of industry practices, pending investigations. It won't take long to get answers...I know that's little consolation for shareholders given the reaction though.