In this paper, we apply the Attainable Region (AR) method to laboratory data in order to find ways of reducing the overall grinding time required to achieve a specific result, and also of maximizing the amount of material in a size class of interest. No work on using the AR technique to improve comminution of a gold ore, specifically targeting optimizing powder filling (U), is available as yet. Results obtained here prove that the AR technique could be successfully applied to determine major trends and also recognize opportunities for improving recovery in milling operations. For different experiments on silica and gold ores investigated, a total of 83% (varying J) and 46% (varying U) time saving were obtained respectively. Further applying the AR method to experiments done on the gold ore varying U from 0.5 to 1.75, a value of 1.0 was confirmed to be optimal. (C) 2016 Elsevier B.V. All rights reserved.