Kinetic tests of mine waste neutralization by coal fly ash, Jerada coal district, Morocco

Abstract

Acid mine drainage (AMD) originating from mine waste (SM) is a major environmental problem of many metal mines in the world, both for operational and abandoned mines. The abandoned anthracite mine of Jerada, which is the subject of this study, is located in northeast Morocco. In the past, this mine has produced about 20 million tonnes of solid mine waste. The aim of this work is to study the feasibility of chemical neutralization of AMD using the alkaline industry residue termed Coal Fly Ash (CFA) as a cover form. The Coal Fly Ash available on site was characterized by chemical and mineralogical analyses, which showed that it contains about 9.43 wt % of calcite, known for its acid neutralization capability. The neutralization capacity of the CFA was then assessed by kinetic (column) tests and leachate analyses, which demonstrated the alkaline character of CFA, and confirmed a significant reduction of generated acidity that nearly reached a neutral pH, but also showed low potentials of oxidation-reduction, and a low content of SO4, Fe, and other soluble elements.