RE:ISLANDcr - XRF - commentSo not asking Alex anything then?? Also that level of XRF machine is only ever going to be in a lab, never in a field setting. The equipment is also never calibrated on any one pure element rather a known mix to verify the % of each element within the acceptable tollerances. If a sample has so little element within it that the acid masks or destroys the element you're looking for it doesn't really matter in the sense of economical grade and recovery just isnt feasable. If the grade is there, there will be enough remaining to get a % from the sample.