Comparison of the Primary Grinding of Taconite in a Pilot-Plant Rod Mill and Ball Mill

Abstract

Progressive improvements in crusher design, screening efficiency, and operating experience along with the down sizing of many taconite operations has resulted in the ability of some crushing plants to produce a substantially finer product. This finer product opens the possibility of replacing the rods in the rod mill with balls. If this replacement could be accomplished substantial savings associated with metal wear and the elimination of rod charging may be realized. The purpose of this study was to compare the performance of a mill charged with rods with the performance of the same mill charged with balls at the pilot scale. The first objective was to establish whether we could achieve the same throughput rate at the same mesh-of-grind in a mill in which the rod media has been replaced by balls. The second point was to determine whether the ball media would create a significant tramp oversize problem.