Abstract: The paper describes the pollution conditions of the tailing reservoir of a uranium mine in Southwest China and the measures taken to control the pollution, with the highlight on the composition of the covering layer for reducing radon emission and the technology and construction of the permeable reactive barriers for treating acidic seepage water.After the remediation, the average ²²²Rn emission is reduced to 0.68 Bq/(m2·s) and the environment radiation rate to(28~176) ×10^-8 Gy/h and the pH value of the seepage water is 8.3, metal uranium concentration 0.03mg/L and SO^2-₄ 180mg/L.The existing problems are analyzed and discussed.

Key words: Uranium mill tailings reservoir, Covering, Permeable reactive barriers, Remediation