3.3.1 Total major elemental oxides
Total major and minor elemental compositions (expressed as elemental oxides) as measured by XRF of selected layers of tailing, spoil and native soil profiles are given in Tables 2 and 3. The composition of major elemental oxides of tailing showed much higher SiO2 content (86-96%) than the native soils (68-76%). The exception for the topsoil of TBB3 spoil profile contained much less SiO2 (43%) associated with some native topsoil containing 15% clay. In tailings, the oxides of potential major nutrients for crops such as Ca, Mg, K, P, S were very low in each soil layer (< 0.2% altogether), indicating these nutrients are major problems in post-tin mining reclamation.