The use of High Pressure Grinding Rollers (HPGR) has been widely reported to have major benefits in the
treatment of minerals such as iron ore and diamonds. To date there have been few investigations into its
use in the treatment of ores containing Platinum-Group Minerals (PGMs). HPGRs are known to reduce
energy consumption and wear costs and improve the throughput in the circuit. In the present investigation
the effect of the comparative use of HPGR and conventional crushing in combination with either dry
or wet rod milling on the flotation of PGMs was studied using batch flotation. Previous studies of a base
metal sulphide had shown that either HPGR or conventional crushing followed by dry milling produced
the highest grades and recoveries (Palm et al., 2010). However in the present study it was observed that a
similar treatment of Platinum-Group Minerals produced the poorest results and the highest grades and
recoveries were obtained for the case of conventional crushing in combination with wet milling. The
HPGR showed no advantages in terms of flotation performance and dry milling produced particularly
poor flotation results.