The experiment was performed in the Universidad Autónoma de Madrid-España. Sampling was performed in Bustarviejo, in the Valle Alto del Lozoya. The Mónica mine is located two km northwest of Bustarviejo, in the southern foothills of the Sierra de Guadarrama. Mining soils are sources of heavy metals; their capacity for retention and mobility depends on the characteristics of the soil. The experiment evaluated different mineral additives (E33P, FeSO4 x 7H2O + CaCO3, KH2PO4 and NPK), and an organic additive (compost) on the availability of the contaminating elements using Lolium perenne as the plant indicator. The variables analyzed were total concentration, available concentration and total concentration in plants, which were analyzed using oneway analysis of variance. We found significant differences among the treatments; the treatment with ferrous sulfate plus calcium carbonate was the most efficient in reducing the availability of toxic elements.