Tropical Soils–Acid Mine Drainage Interactions: Breakthrough Curves and Some Transport Parameters

Abstract

The interactions between acid mine drainage (AMD) and three tropical clayey soils have been studied through hydraulic conductivity and batch sorption/dissolution testing. After 19–24 pore volumes of AMD flow through the soils, the measured final hydraulic conductivity ranged between 1.1× 10−11 and 3.3× 10−11 m∕s . The pH, electrical conductivity, and solute breakthrough curves obtained suggested the soils had low acid-buffering capacities. Also, several chemical species were released from the soils due to AMD attack of soil grains and mineral. The batch tests revealed high dissolution of species such as sodium, cobalt, and sulfate from the soils by AMD. The results also indicated dissolution of metals from soil constituents, desorption of chemical species, and transformation and dissolution of soil minerals due to AMD attack. The results of the study showed that, in general, the soils were not effective in attenuating contaminants present in the AMD. Thus, they may not be used alone to construct liners fo...