ABSTRACT
This chapter shows that post-mining damage to stored bauxite soils occurs not only in the vertical direction, but also horizontally, in soil dispersion and strength. Decreased soil organic matter and lowered porosity can cause soil dispersion. P. Rengasamy et al. decreased soil dispersion in dispersive soils with the addition of organic mulches on subaerially exposed soil surfaces. Results of the Emerson Dispersion Tests revealed considerable dispersion in areas of replaced topsoil on the mined-out bauxite lands. Salinity and sodicity reduce crop productivity and soil health. Opencast bauxite mining produces stockpiles of disturbed, stored topsoil, which are often contaminated with subsoil. Sodium ions are highly mobile in the soil solution and so they accumulate in the lower parts of the landscape. Yet, Mark Anglin Harris and S. Omoregie noted zones of clay enrichment in bauxite overburdens. Coverage of bare patches in bauxite soils with vegetation may preempt exacerbation of dispersion by extreme climate changes.
