In the concentrator of a gold mine,the life of ball mill linings differs and there is a huge gap between the grading performances of grading equipment.In light of these facts,the ball mill linings and grading equipment are optimized and renovated.The ball mill linings shift from alloy steel linings to rubber linings.The linings parameter and structure are optimized,reducing the lining weight by 2/3 and narrowing the gap of lining life.The installation of pressure meter to hydraulic cyclone,the grading equipment in milling system,controls the concentration gap of hydraulic cyclone under 3 % and the fineness gap under 5 %.At the same time,the costs are compared to decide whether to repair damaged parts or purchase new parts.According to related statistics,the investment in parts can be saved by 0.4 million yuan annually.