Abstract: A systematic study was carried out on the suitable medium ratio of the primary mill in Jianshan Iron Mine of TISCO for optimizing the grinding-classification operation， fully tapping the potential of mill， reducing the grinding consumption， and realizing sustainable development of the enterprise. The results indicated that it got the best grinding effect for primary mill when the medium mass ratio was 35%∶25%∶20%∶20% corresponding to the ball diameter of [?]120 mm， [?]110 mm， [?]80 mm， and [?]60 mm. The grinding effect of forging ball was better than that of casting ball. Compared with field data， the utilization coefficient of mill either for raw material or for new generation of -0.074 mm was increased more than 4%. The expected target was fulfilled.

Key words: Ball mill, Grinding medium ratio, Grinding medium type, Grinding effect