Sensitivity analysis of acid mine drainage prediction leaching tests
- South Carolina Dept. of Health and Environmental Control, Columbia, SC (United States)
- Univ. of South Carolina, Columbia, SC (United States)
A statistical sensitivity analysis was conducted to identify predominant factors controlling leachate quality from humidity cell, soxhlet, and column overburden leaching tests. Soxhlet and weathering cell tests exhibited the greatest sensitivity to (1) storage condition (temperature and humidity); and (2) leaching interval (time between Teachings). The factors of particle size and leachant temperature played secondary roles in influencing leachate quality. High temperature, oven sample storage selectively promoted pyrite oxidation over carbonate dissolution, with pyrite oxidation reactions that were continuous and thermally enhanced, and discontinuous calcium carbonate dissolution which varied with the water content of the overburden sample. For short leaching intervals, (2 days), pore water was retained for a greater percentage of the total storage interval, and acidity produced by pyrite oxidation was neutralized by carbonate dissolution. For longer leaching intervals (7 days), pore water was retained for a smaller portion of the total storage interval, and acidity was not neutralized by carbonate dissolution. Weathering cells and columns exhibited sensitivity to particle size which controlled the rate of water movement through the overburden material. Short residence times for pore water in the large grained overburden samples favored low alkalinity production. Fine grained overburdens, with small pore sizes, resulted in slower water movement favoring greater alkalinity production and acid neutralization. Acid and sulfate production rates exhibited logarithmic correlation with particle size. Acid production rates for high NP overburdens were positively correlated with the logarithm of particle size, while acid production rates for low NP overburdens were negatively correlated with particle size. The results of this study aid in the selection and design of overburden leach tests for acid mine drainage prediction.
- OSTI ID:
- 613850
- Report Number(s):
- CONF-9705128-; TRN: 98:001000-0039
- Resource Relation:
- Conference: 14. annual national meeting of the American Society for Surface Mining and Reclamation (ASSMR), Austin, TX (United States), 10-15 May 1997; Other Information: PBD: 1997; Related Information: Is Part Of Vision 2000: An environmental commitment; Brandt, J.E.; Galevotic, J.R.; Kost, L.; Trouart, J. [eds.]; PB: 799 p.
- Country of Publication:
- United States
- Language:
- English
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