Abstract: To address the unreasonable size distribution of the grinding media and the poor particle size distribution of the grinding product from the large Φ7.9 m × 13.6 m ball mill at Inner Mongolia Mining, the initial ball charge composition was determined to be ϕ70∶ϕ50∶ ϕ40∶ϕ30 = 20∶40∶30∶10 using the semi-theoretical ball-diameter method based on the mechanical properties of the ore and the particle size distribution of the grinding feed. The comparative grinding test results show that, compared with the on-site scheme, the recommended initial ball charge scheme reduces the yield of the excessively coarse +0.2 mm fraction by 1.29 percentage points, increases the yield of the readily beneficiated intermediate −0.074 to +0.010 mm fraction by 5.10 percentage points, and increases the yield of the −0.074 mm fraction by 4.63 percentage points. The discrete element simulation results show that, relative to the on-site scheme, the recommended initial ball charge scheme increases the total collision energy by 7 316 706.574 J and the combined proportion of collision energy attributable to steel ball-ore and ore-ore collisions by 3.79 percentage points, while decreasing the combined proportion attributable to steel ball-steel ball and steel ball-liner collisions by 1.31 percentage points and increasing the number of collision events with collision energy ≥0.01 J by 4 558 932. The discrete element simulation analysis confirms that the recommended initial ball charge scheme is reasonable and provides a reliable basis for parameter selection at the concentrator.