Reuse of excavated soils in MSW landfills liners is not always feasible, due to their geotechnical properties that have to meet the requirements of the existing regulation. This paperdeals with a case history occurred in the north east of Italy and shows an in-situ mixing procedure of a sandy silt with a medium plastic clays, able to achieve a homogenous mineral barriers suitable for landfill. A laboratory investigation was firs carried out to evaluate the best percentages of silt and clay in the mix. Field tests were planned using a soil stabilizer machine for mixing the two soils at different percentages by weight. Laboratory tests, performed on samples collected in situ, showed a very good soil homogenization. In this case history, the reuse of a relevant quantity of excavated silt, has also assumed a strategic importance related to economic issues and environmental sustainability