100% ore! Avg 40g/t Au 1km x 200m to EOH all holes, OP mining 2019, page-146

Maybe by not using a collector for the initial smelt they are attempting to reduce the amount of collector (copper) needed given the resulting resmelted slag concentrates the PGMs and so has less mass than the smelt ? Could that be analogous to how some refractory ore is "roasted" before treatment ?

" In the case of sample EMD-001 2-6m an initial smelt was conducted without a collector metal before proceeding with the method described above. A PGM-rich button was also precipitated which was subsequently dissolved and read on the AA."