Long-term predictions of sulphate release by pyrite weathering from heap sediments into the ground- and surface water
The objective of this study is the prediction of contaminant loads related to acid mine drainage from overburden spoil piles at open-pit lignite mines. An assessment of future sulphate discharge released from the unsaturated zone as a result of pyrite weathering was performed, based on measurements of soil-gas, pore water and sediment chemistry over a profile of 9 m in the unsaturated zone of an abandoned lignite mine heaps.Observed pyrite concentrations range between 0.01 and 0.04 wt.％, sulphate concentrations in the pore water reach 1800 mg/L, total iron shows values up to 640 mg/L and pH decreases to 1.96 at 10m depth. The results were interpreted using the reactive transport code Sulfidox. The model was calibrated for effective diffusion using measured oxygen and sulphate concentrations in the unsaturated zone of the heap. Scenario calculations indicated a rising discharge of sulphate into the adjacent surface water for the next 80 years due to continued pyrite weathering. The influence of secondary mineral precipitation and dissolution is small.
C.Kohfahl A.Pekdeger P.L.Brown C.M.Linklater P.Irannejad
Institute of Geological Sciences, Freie Universit(a)t Berlin,Department of Earth Sciences, Berlin, G Rio Tinto, Bundoora Vic, Australia SRK Consulting, Sydney, NSW, Australia Institute of Geophysics, University ofTeheran, Tehran, Iran
国际会议
第十二届水-岩相互作用国际研讨会(P0roceedings of the 12th International Symposium on Water-Rock Interaction)
昆明
英文
335-338
2007-07-31（万方平台首次上网日期，不代表论文的发表时间）