Changes in feed size distribution can have significant effects in rod mill grinding. The product sizing resulting from wet batch milling of a tin ore showed little influence on fines production after truncating the feed at either the coarse or fine end. The addition of fine material caused a less amount of fines to be
produced and a possible increase in grinding at coarse sizes, although this is complicated by the changing feed size distribution. The changes in feed size distribution caused no tendency for preferential grinding of the cassiterite.