IMPORTANCE OF STATIC TESTS FOR THE PREDICTION OF AMD POTENTIAL OF CEMENTED PASTE BACKFILL

Cemented paste backfill (CPB) is an engineering mixture of mine tailings, cement and water. Tailings can commonly contain sulphidic minerals. In this case, acid mine drainage (AMD) may occur due to the oxidation of sulphidic minerals present in the body of the CPB. In general, AMD lowers the pH of the medium and water environment and may cause heavy metal release. Therefore, AMD potential is an important parameter to be considered with regard to environmental aspect. Static tests are widely used to determine the AMD potential of sulphidic materials. When neutralization capacity is higher than the acid generation potential, tailings can be safely stored from an environmental point of view. In this study, AMD potential of CPB material produced from sulfur-containing fine tailings is investigated. In this scope, a static modified ABA test was performed on fine sulphidic tailings (TA) and CPB produced from the same sulphidic tailings+7%wt. SR5 cement+water for the first time. Findings suggests that the CPB material had a lower AMD potential (~10%) compared to the tailings. Acid generation capacity of both tailings and the CPB was found to be dominant due to the high sulphide content (~30%wt. and ~28%wt.), respectively. However, CPB was observed to maintain its structural integrity and did not release acidic water for at least 40 weeks. This study showed that a well-designed CPB can be effectively used as an environmentally friendly mine tailings management method.