Abstract
The issues of acid mine drainage (AMD) from mining activities is not a new phenomenon to the
present day developing South Africa as well as in most developed countries around the globe. However, the
persistent rise in environmental contamination in South Africa is drastically attracting massive concerns. Vital
concerns of AMD in South Africa still remain the threat to soil, surface, subsurface and ground water reserves
among others, which consequentially impact human and environmental health. This insistent challenge has
given rise to the need for investigating the buffering efficacy of clayey mineral soils for use as natural
contaminant barriers to contaminant species from AMD. Therefore, the study presented herein, was channeled
towards assessing the chemical alterations in three clayey soils from permeation and interaction with AMD via
successive protracted percolation up to 18-25 pore volume passage of AMD through the respective soil
medium. The final hydraulic conductivity measured, ranged between 1.3 × 10-11 m/s and 1.5 × 10-11 m/s. The
obtained pH, electrical conductivity and solute breakthrough curves indicated the soils had low acid-buffering
efficacies. Chemical species such as Na, Co and SO42- were highly dissolved due to attack on the soil grains by
AMD. Chemical species were also released from the soils including the dissolution of metals and desorption
of chemical species from AMD attack. As such, the study revealed that the buffering efficacies of the respective
tested clayey soils to AMD chemical contaminants were generally ineffective.