Phosphate Amendments for the Inhibition of Acid Mine Drainage Generated from Sidi Kamber Tailings Facility

Abstract

The aims of this paper was to evaluate the efficiency of phosphates product and by-products from the Djebel Onk mine for the control of acidic mine drainage generated by exposure of Sidi Kamber mine tailings to climatic conditions. Kinetic tests in humidity cells were carried out according to the modified ASTM standard, was used to invistigate the geochemical behaviour of the Sidi Kamber tailings mixed with phosphate materials (phosphatic limestone wastes, raw low grade phosphate ore and phosphate mine tailings) after being characterized. All amendment compositions led to an increase of the pH of the leachate from approximately 3 to circum-neutral values. Humidity cells experiments indicated that the materials were adequate to immobilize Pb, Zn, Cu and Fe by about 99% and prevent their release through the tailings. The tests have also shown that the metals concentrations within the leachate are lower than the limits allowed by Algerian legislation for industrial liquid effluents. Among the tested material amendments, PLW was more effective than other products in immobilizing metals. The results are most probably related to their Ca-carbonate content and/or adsorption capacity.