A copper mine in Yunnan Province has some problems,such as long transportation and ventilation lines,high consumption and low efficiency of ventilation system.By analyzing the problems exist⁃ing in the ventilation system of the copper mine,the reasons for the high effic...MORE A copper mine in Yunnan Province has some problems,such as long transportation and ventilation lines,high consumption and low efficiency of ventilation system.By analyzing the problems exist⁃ing in the ventilation system of the copper mine,the reasons for the high effic...