Spatial variation of AMD related CO₂ emissions on reclaimed mine spoil
"Carbon dioxide (CO₂) from acid mine drainage (AMD)-carbonate neutralization reactions in reclaimed mine spoils, can intermittently invade homes and structures constructed on or adjacent to these spoils in hazardous and even lethal concentrations (>15%) and rendering them uninhabitable. This phenomenon is beginning to be recognized as an emerging environmental, safety and health threat with potential environmental and financial liability for mine operators, developers and owners. Like in natural soils, soil temperature and moisture, and possibly elevation are likely to influence CO₂ emissions from reclaimed mine spoils. However, mine spoil soils are heterogeneous and have significant convective transport due to exothermic AMD reactions. Therefore, assumptions made for natural soils may not hold. The aim of this study was to foster further understanding of the processes controlling the efflux of CO₂ from reclaimed mine spoils and evaluate the effectiveness of accumulation chamber (AC) flux measurement in identifying and delineating this hazard. AC measurements, isotope ratio mass spectroscopy, and statistical techniques were applied to three reclaimed mine sites in the United States of America. Among the study findings are that: (i) there is correlation between CO₂ flux and elevation, soil temperature and moisture; (ii) CO₂ fluxes are not always random but spatially autocorrelated; (iii) AMD-derived CO₂ emissions are normally too low to successfully be used to delineate hazards. This pioneering effort also makes recommendations for future work that could make AC flux measurement more effective for this emerging hazard"--Abstract, page iii.
Missouri University of Science and Technology
Networked Digital Library of Theses and Dissertations