Size-Resolved Process Mineralogy of a Primary Sn-W Polymetallic Ore Composite from the Syrymbet Deposit, Kazakhstan

Complex Sn-W ores require size-resolved characterization because metal grade and target-mineral liberation may respond differently to comminution. A composite designated Comp 1 Sulphide from the Syrymbet deposit, Kazakhstan, was stage-ground to a reported P80 of 127 µm and divided into +150, −150/+75, −75/+20, and −20 µm fractions. Size-by-assay chemistry was integrated with qualitative X-ray diffraction, QEMSCAN particle mineral analysis and specific mineral search, SEM-BSE/EDS, and electron-probe microanalysis. The −75/+20 µm fraction contained the highest Sn and W grades, 0.96 and 0.08 wt.%, and the highest modal abundances of cassiterite and W minerals, 1.18 and 0.21 wt.%. Its free plus liberated proportions were 76.0% for cassiterite and 97.1% for W minerals. The −20 µm fraction showed higher cassiterite liberation, 82.7%, but lower Sn and W grades, 0.56 and 0.04 wt.%, as micas, chlorite, and clays increased to 54.3 wt.%. Cassiterite hosted 95.5–98.1% of Sn. A theoretical 20–150 µm product represented 52.6% of feed mass and contained 61.7% of Sn and 65.7% of W, but As was enriched by a factor of 1.28. The results provide an internally reconciled, size-resolved process-mineralogy case study of a primary Sn-W polymetallic ore and indicate that size-dependent divergence between grade and liberation and concurrent As co-enrichment constrain the interpretation of size-based classification scenarios.