Abstract:The S pit of a copper mine is reused to accommodate acidic wastes. The backfill has reached 525m elevation and is expected to reach a final top elevation of +575m. The waste backfill in S pit produces polluting acidic water. On the eastern slope of S pit,there is a strong aquifer of Quaternary alluvium(Qaplh)with a length of about 1500m. Water inflows from Chindwin River and Yawma River into the pit through this layer. Under normal conditions. However, as the level of acidic backfill rises in S pit, acidic waste water will enter the strong aquifer of sand and gravel on the eastern slope by dispersion and seepage after the acidic pit water reaches above the 545m bench, which will contaminate the nearby groundwater, Yawma River and soil. Based on the experimental research of related data, composite liner barrier cutoff wall was proposed in this study for the eastern slope of S pit to stop seepage. The seepage control efficiency of the cutoff wall was simulated in Visul Modflow software and results showed that composite liner barrier cutoff wall could stop pollutants from contaminating groundwater for 100 years.
