"Extraction values contain some high grades. Whether these can a...

"Extraction values contain some high grades. Whether these can a replicated in assays is key and should be known soon (months)."

How do you know there are high grades if you don't know the accuracy of your measurement?

Without a measure of your assays accuracy your answer could simply be wrong, ie your method might grossly overestimate the amount of the gold in the sample in some way. You could be replicating the wrong result.

There need to be error bounds on any measurement that is made, this is a basic principle of experimental science 101. Esh