Abstract: In order to improve the production efficiency of Mirador Copper Mine，aiming at the prob⁃ lems of low grade and recovery rate of copper concentrate and large fluctuation of beneficiation index， based on the study of process mineralogy，the optimization test of reagent system，ball mill and flotation col⁃ umn parameters of beneficiation equipment was carried out.The results show that copper minerals are recov⁃ ered by copper-sulfur bulk flotation，rough concentrate regrinding and reconcentration process，with xan⁃ thate and Z-200 as collectors，F-501 and IBC as foaming agents. When the filling rate of ball mill is 26%， the grinding fineness is -0.045 mm 90.0%，the aeration volume of flotation column is 160~190 m3/h，and the leaching water volume is 50 m3/h，the copper concentrate with copper grade of 27% and copper recovery rate of more than 90% can be obtained，which achieves better beneficiation index and provides technical ba⁃ sis for the production of the concentrator.

Key words: low-grade copper sulfur ore, bulk flotation, regrinding, productive practice