Utilization of spilitic mining wastes in the construction of landfill bottom liners

In the present research work the possibility of spilite valorization, a mining waste produced during the exploitation of nickeliferous laterites from LARCO Mining and Metallurgical Company, as an alternative material for the construction of compacted landfill liners was examined. For that purpose, different types of mixtures were tested with bentonite content up to 3 wt%. Particle size distribution, chemical analysis, mineralogical analysis by X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG) and microstructure examination by scanning (SEM) and transmission (TEM) electron microscopy were used for the spilitic sand characterization. The evaluation of the produced spilitic sand-bentonite mixtures was carried out by determining the liquid limit (WL), the plasticity index (PI), the organic matter content, the Proctor compaction and the hydraulic conductivity. According to the results, the hydraulic conductivity coefficient of the mixture with 3 wt% bentonite addition was less than 10−9 m/s, satisfying the requirement for landfill liner materials.