Abstract: The engineering design optimization schemes for the dump， ditch and acidic reservoir of the Mirado copper mine are briefly described. The merits and demerits of the optimized scheme are qualitatively and quantitatively analyzed and compared with that of the original scheme from the aspects of construction period， investment， production and operation cost， safety and environmental protection. According to the optimized mining projects in dump， ditch and acidic reservoir， the total length of the north-south ditch is shortened by nearly 3 km， the amount of earth and rocks is reduced by about 30%， the amount of reinforced concrete in ditch is lowered by about 20%， and the investment is cut by more than 21%； Three total acidic reservoirs in the north and south mines is reduced to two； The average transportation distance of waste rock in stope is shortened by 1 km. Through the construction practice， the optimized scheme of the dump in south mine saves more than 26.89 million US dollars in the capital construction period than the original preliminary design scheme. The investment within the overall service life of the dump in North and South Mines is reduced by 31.21 million US dollars， with the operation cost reduced by 51 million US dollars， the acid water treatment capacity reduced by 9，000 m3 per day， and the annual operation cost lowered by about 3 million US dollars. The optimized plan provides a successful example for overseas mine construction.

Key words: Mirador copper mine, Waste dump, Intercepting ditch, Scheme optimization, Practice