Ann: Voluntary Suspension, page-45

Strange things can happen.
Years back a company had some quite good results in Cu, Au ppb in a soil sampling program with widely spaced lines.
Infill auger drilling, close spaced, between the wide spaced lines on the whole program came up with nothing. The contractor was asked why, and he replied that there was obviously nothing there.....
Turned out the initial contractor used to replace his tungsten auger bits with a bronze high in Copper and Gold....... and all the CU,Au anomalous values came from his bits.
There really was nothing there.

GZ