Abstract: In order to improve the operation efficiency and equipment stability of the ball mill of Longqiao Mining Industry，in view of the problems of short service life，frequent maintenance and frequent slurry leakage in the use of traditional high manganese steel liners，bimetallic composite liners have been in⁃ troduced into the one-stage grinding system since 2010，and structural optimization and installation process improvement have been continuously carried out.The production practice shows that the bimetallic compos⁃ ite liner has shown significant advantages in wear resistance，impact resistance and service life. The average service life can reach 24 months，which is nearly 5 times that of high manganese steel liner. The average an⁃ nual replacement times are reduced from 2.4 times to 0.5 times，which greatly reduces the unplanned shut⁃ down time，improves the continuity and reliability of equipment operation，and improves the beneficiation efficiency.At the same time，the maintenance cost is significantly reduced，and the annual comprehensive cost is 249 000 yuan，which promotes the construction of green mines and provides an effective path for min⁃ ing enterprises to reduce costs and increase efficiency.

Key words: bimetallic composite liners, ball mill, performance optimization, economic benefits