In order to limit the production of acid mine drainage, different techniques can be used for mine site rehabilitation. Among of these techniques, one find oxygen barriers such as covers with capillary barrier effects (CCBE). A CCBE is made of different layers, the most important of which is the moisture-retaining layer (MRL). This layer can be made using optimized mixtures of till and sludge produced from AMD treatment using carbonate materials. Indeed, laboratory studies showed that material mix (MM) of a till and sludge at an optimal ratio can achieve the required hydraulic properties for an efficient MRL. To evaluate the performance of three MMs as MRLs, instrumented columns simulating CCBEs placed over sulfide-rich tailings were used. Each column was subjected to wetting-drying cycles where matric suctions were measured. Leaching water was also collected and chemically analyzed at the end of each cycle. Results of these investigations showed that the suctions measured in the MRL were below the air entry value (AEV) for the three tested MM, and the leachate quality did not show production of AMD. According to these results, the MM tested could be used as MRLs in CCBEs. However, it is recommended to test their behavior at a field scale in order to integrate mine site climatic conditions.