Abstract: In order to improve the operation stability and equipment operation and maintenance effi‐ ciency of the ball mill control system in Anhui Lujiang Longqiao Mining Co.，Ltd.，aiming at the problems of equipment aging，spare parts outage，frequent failures，low automation level and data island in the orig‐ inal ball mill electronic control system，a comprehensive automation upgrade is implemented with a new generation of PLC（S7-1200/1500 series）as the core，integrated intelligent sensing，advanced algorithms （such as Kawerce multi-dimensional joint judgment）and expert knowledge base. The overall design of the upgrade scheme，the realization of the core control strategy，the key difficulties and solutions in the proj‐ ect implementation are described in detail.The transformation results show that the operation stability of the new system is significantly improved，the unplanned shutdown is greatly reduced，the equipment operation rate is significantly improved，and the operation and maintenance efficiency is improved by more than 75%. The data connection with the MES/ERP system of the whole plant is realized，which lays a solid foun‐ dation for the intelligent and digital construction of the concentrator，and has significant economic benefits and promotion value.

Key words: ball mill, automation upgrade, PLC transformation, intelligent control, fault diagnosis, benefit analysis