Converting AG to SAG mills: The Gol-E-Gohar Iron Ore Company case

Abstract

At the concentration plant of the Gol-E-Gohar Iron Ore Company (Iran) three 9m×2.05m AG (autogenous) mills (fixed speed) are used in parallel in a dry operation. The performance of AG mills has been lower than the target value indicated by an increase in the product size (P 80; 80% passing size) from 450μm (target) to 515μm 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., 22.5cm) could provide an appropriate charge trajectory. When the proposed liners installed in one of the AG mills, 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 501μm. © 2011 Elsevier B.V.