Markus Anda

and 4 more

Characteristics of refused materials are prerequisite information required to determine the strategic reclamation of extreme land degradation in post-tin mining areas. The objective of the study was to evaluate mineralogical, chemical, and physical properties and heavy metals of spoil and tailing as the basis for reclamation measures. Seven representative soil profiles were made and sampled to a depth of 130 cm for various soil analyses. Results showed that tin mining has drastically altered the soil texture from sandy clay loam under native conditions to loamy sand and sand under post-tin mining. Mineralogical constituents of refused materials were mainly mineral resistant to chemical weathering, consisting of predominant quartz with small amounts of tourmaline, opaque, zircon and garnet. Total X-ray fluoresce elemental analysis showed extreme high SiO2 content (92-96%) associated mainly with quartz mineral, and extremely low oxides of Ca, Mg, P, K and S (< 0.2% altogether). This suggests all nutrients are severe problems for crops. Type of total heavy metals showed the Cr2O3 was high in sandy tailing (204 - 286 mg kg-1), while the SnO was low (0 -153 mg kg-1) and they were preserved in the structure of host minerals, thereby the health risk is negligible. Based on many serious constraints of soils, the strategic reclamation to recover soil productivity and ecological function was the building up soil organic matter, establishing “pot planting point” technique, complete fertilizer application, and selection of crops with an ability to fix N nutrient from the atmosphere, and adaptive to low soil nutrients.