Acidic mine soils can be effectively neutralized once they have been again spread at the
reclamation site by applying either cement kiln dust (CaO) or limestone (CaCO3). Lime
application rates must account for both past and future pyrite oxidation in order to
maintain neutral soil pH levels over time. Lime addition is a common method to decrease
the heavy metal mobility in soils and their accumulation in the plant as it increases the pH
of soil. Plants like Gravellia robusta, can be planted at acidic dumps (pH 3.6-3.9), which
increases the soil pH (Gitt and Dollhopf, 1991). Organic amendments such as woodchips,
composted green waste or manure, biosolids etc also increases the soil pH, in addition
improves soil structure, water holding capacity, cation exchange capacity, provide a
slow-release fertilizer and serve as a microbial inoculum (Tordoff et al., 2000; Jordan et
al., 2002).