『Abstract
Investigation was carried out to characterize the sulfidic mine
spoils in the surface layer of a spontaneously combusting waste
rock stockpile. The objective was to assess its potential impacts
on acid mine drainage generation. The results show that there
were substantial amounts of elemental S and various sulfate minerals
in the weathered materials, indicating the occurrence of significant
sulfide mineral oxidation in the investigated spontaneously combusting
mine spoils (SCMS). It is likely that the surfacially-occurring
elemental S was derived from the deeper waste rock layers experiencing
spontaneous combustion under limited aeration conditions. The
significantly higher acidity, EC and SO42-
concentration in the SCMS, relative to the Non-SCMS suggest that
spontaneous combustion is a much faster and more powerful process
driving sulfide-derived acid generation, compared to microbially-catalyzed
oxidation of sulfide minerals. The export of acid sulfate materials
from the spontaneously combusting waste rock stockpile not only
generates severe acid mine drainage but could also act as an inducer
for biologically-catalyzed oxidation of newly exposed sulfide
minerals in the areas surrounding the stockpile.』
1. Introduction
2. Materials and methods
3. Results
3.1. Mineralogical composition
3.2. Chemical composition
3.3. pH, EC, soluble titratable acidity and SO42-
3.4. Soluble metals
3.5. Change in pH of extract during the successive extraction
3.6. Change in titratable acidity of extract during the successive
extraction
3.7. Change in EC of extract during the successive extraction
3.8. Change in metal and SO42-
of extract during the successive extraction
4. Discussion
5. Conclusions
Acknowledgements
References