Abstract: In order to solve the problem of serious shortage of processing capacity of self-grinding machine in Zhongguan Iron Ore Dressing Plant，the self-grinding process is transformed into semi-selfgrinding process by adding steel balls to improve the grinding effect. At the same time，by changing the cy⁃ lindrical sieve at the discharge end of the self-grinding mill into a self-return sieve，the size of the sieve hole is increased，the ability to remove the refractory stone and the efficiency of the ball mill are improved， and the problem of discharging refractory stone is solved. Increase the iron remover to eliminate the influ⁃ ence of large iron on the process；adjust the ball mill steel ball ratio to improve the grinding efficiency；opti⁃ mize the material and structure of the self-grinding mill liner to improve the service life and operation rate. Through a series of optimization and adjustment，mill processing capacity exceeds the design value，energy consumption and recovery rate reached the industry leading level；the formed SABC-B process has the characteristics of small process modification，low cost and good effect，which can provide experience refer⁃ ence for mines that need process optimization due to changes in ore properties.

Key words: semi-autogenous grinding, beneficiation, stubborn stone treatment