As I recall there two stuck keys on the report prep keyboard... -1
But seriously, my kiss on the -1 issue is treat all -1 entries zeros. Now I betcha that interpretation moves the resource calculation number. And I argue that is the valid move -- the assay result was the egos eye. Not an ISO lab but still it is a measure that is MUCH better than ignoring the -1 and assuming an average value applies which is what it appears PG is doing.
I wonder if the twinned holes were test of -1 intercepts to confirm a treat as zero interp. Might explain why those assay results are so slow in being reported.