At the concentration plant of the Gol-E-Gohar Iron Ore Company (Iran) three 9 m × 2.05 m previous termAGnext term (autogenous) previous termmillsnext term (fixed speed) are used in parallel in a dry operation. The performance of previous termAGnext termprevious termmillsnext term has been lower than the target value indicated by an increase in the product size (P80; 80% passing size) from 450 μm (target) to 515 μm and low power draw (50% of nominal). By simulation it was found that increasing the liner lifter face angle from 7 to 30° while keeping the original lifter height (i.e., 22.5 cm) could provide an appropriate charge trajectory. When the proposed liners installed in one of the previous termAGnext termprevious termmillsnext term, the throughput increased by 27%; when 5% (v/v) balls were added the throughput increased by 40%. The product size also decreased from 515 to 501 μm.