It is a completely fantastic result no matter which way you...

It is a completely fantastic result no matter which way you slice it.

Just a caution against assuming a similar positive bias for the pXRF results for MHRC045 based on what we have just seen with MHRC029.

Reason: the pXRF results for MHRC029 were taken through the green-plastic RC sample bags. All subsequent pXRF intersections have been made through the calico bags (including MHRC045).
The standard green polyprop RC bag has a thickness of around 150um and density of ~1.2 (g/cm3) vs calico bag with a density of around 200um and density of 2.2 (g/cm3). Therefore, the energy transmission effectiveness will not be the same.
Numerous studies have shown calicos have some of the worst transmission effectiveness, with only ~60% of the Kα X-rays passing through for iron, more significant for lighter elements. So there is potential that the assay results from these will be even more than the 30% difference noted from MHRC029. But additional complication is that calico (cellulose) has measurable Cu content itself (positive bias), this makes predicting the pXRF bias a difficult task (until there is a reference for both).
Simplest solution IMO….measure the pulverised RC samples directly in the RC or calico bags NOT through either of them.

Anyway, my point is just that it is unlikely to be the same difference given the variability of the sample bag media - it may be be better (hopefully) or worse.

great result...well done all holders