Optimizing the Characteristics of theMotion of Steel Balls and their Impacton Shell Liners in SAG Mills

The equations governing the motion of steel balls and theirimpact onto shell liners in industrial Semi-Autogenous Grinding(SAG) mills are derived in full details by the authors and areused in order to determine the effective design variables foroptimizing the working conditions of the mill and to avoidsevere impacts which lead to the breakage of SAG mill shellliners. These design variables are the lifter height H, theworking coefficient offriction OF FERICTION face inclination angle tp,steel ball size re, mill rotational velocity OJ, and mill size R. Inorder to optimize the operating conditions and avoid severeimpacts to its shell liners, the effect of these parameters need tobe studied. The effect of lifter height (H) and the coefficient offriction (11) on some of the main impact characteristics aresimultaneously investigated for a SAG mill in SarcheshmehCopper Complex. It was shown that as the lifter height or thecoefficient ofFiction increases , the impact position tends tomove upward, but the maximum impact force and the absolutevalue of the maximum principal stress decreases , reducing theimpact severity.