Enhancement of extraction procedures on cations and anions in mine spoils

A laboratory study was conducted to compare four extraction techniques for extractable cation in acid mine spoils collected from coal fields of Kentucky, West Virginia, and Virginia. The study demonstrated that extracting the spoil with HCl+H{sub 2}SO{sub 4} extracted the most cations and correlated the best with NH{sub 4}OAC extraction. However, it was also observed that comparison between HCl+H{sub 2}SO{sub 4} extraction and the BaCl{sub 2}+TEApH 8.2 extraction is the best assessment in comparing the ability of a given spoil upon liming to build pH-dependent charge and consequently acid neutralization potential. It was observed that the mine spoils were very low in cation exchange capacity (CEC) and high in anion exchange capacity (AEC) irrespective of extracting technique. Furthermore, these spoils contain a significant quantity of readily available aluminum which could be easily evaluated by the rapid extraction technique such as HCl+H{sub 2}SO{sub 4} or the NH{sub 4}Cl extraction. The measurements made in the saturation paste and saturation extracts indicated that most spoils have a high calcium and magnesium concentration and could release sulfate as high as 250 ppm which is the limit recommended for drinking water.