Influence of igneous intrusions on coal flotation feasibility : the case of Moatize Mine, Mozambique

Abstract

In this study, the influence on the properties of coal caused by proximity with an igneous intrusion in the Moatize mine was evaluated, together with the possibility of beneficiating such coal in the flotation circuit of the plant. For this purpose, extensive characterizations of samples collected at different distances from the intrusion were carried out, followed by a lab-scale replication and analysis of the flotation conditions used in the Moatize plant. The results showed that coal was negatively affected by the closeness to the dyke, with it being unfeasible to beneficiate coal at a distance of 2 m from the geological contact. However, for a 20 m distance, it proved possible to achieve yields higher than 77% with ash contents below 10%, depending on the reagent system used.