Abstract: In order to eliminate the surface environmental pollution caused by the discharge air out⁃ side the return air shaft of an underground mine，in view of the formation of white fog column at the well⁃ head of the return air shaft of an underground mine in winter，and the environmental pollution caused by the discharge water mist，dust and harmful gases，the investigation of the discharge intensity of the pollution factor of the return air shaft and the study of the emission reduction technology were carried out. Through 24 h continuous sampling and analysis of the waste air in the return air shaft of underground mine，it is con⁃ cluded that the waste air outside the return air shaft has the characteristics of large flow，low concentration and high total amount，and the concentration reaches the peak value 1 h after underground large blasting. The test results show that the defogging effect of the mesh mist eliminator is better than that of the corrugat⁃ ed plate mist eliminator，and the combined mist eliminator is better than the mesh mist eliminator. The thicker the wire mesh demister is，the better the demister effect is.According to the test results，a combined mist and dust removal scheme is proposed. The engineering practice shows that the scheme can effectively eliminate the white mist column in the return air shaft. The system resistance is less than 200 Pa，and the air volume of the ventilation system is reduced by 3.2%，which has little effect on the ventilation system.

Key words: underground mines, return air well, sewage treatment, effect evaluation