Conclusions
Mineral composition of post-tin mining provides strategic roles in
providing the potential amount and type of native nutrient sources and
heavy metals which are basic information required to determine soil
nutrient management in supporting rehabilitation measures.
Post-tin mining areas have many severe constraints for crop development
and ecological reclamation. The characteristics of tailings are a
dominant sand fraction (up to 96% sand), limited clay fraction
(< 14%), dominant quartz minerals, low water holding
capacity, extremely low organic matter and all nutrients (especially N,
P, K, Ca, Mg, S), slightly acid, and the limited number of weatherable
minerals (potential native nutrient sources). Total elemental oxide
composition was dominated by SiO2 (92-96%) deriving
from quartz minerals.
Heavy metals were occluded in structures of hot-minerals meaning that
they were less availability and low health risk. Heavy metals consisted
of mainly Cr and small amounts of Sn, Pb and Hg. Sn availability was
minimum in all cases since it was preserved in host-mineral structure
(cassiterite) which was resistant to chemical weathering.
Without technology intervention, the reclamation of post-tin mining
areas was unlikely and was uneconomically feasible in the short-term.
Strategic reclamation includes building up soil organic matter content,
establishing pot planting point technique, thoroughly incorporated
initial topsoil if it is available, complete fertilizer application and
selection of adaptive crops with an ability to fix nutrient from the
atmosphere.