Abstract

This study evaluates an optimization model that addresses the extraction sequence and waste dump design to maximize the net present value (NPV) of the mine and reduce the impact of acid mine drainage (AMD). The block model considers the pyrite grade and divides the waste materials into potentially acid-generating (PAF) and non-acid-generating (NAF) materials. The extraction sequence is modelled using mixed integer programming, aiming to maximize the NPV. As a result, it was possible to implement the evaluated model and generate a production plan in a 2D conceptual case study. This plan allows for the encapsulation of PAF materials in the center of the waste dump, but it is conditioned by a high production rate of 18,500 tons per day (tpd), resulting in a mine life of 4 years and a positive NPV at a discount rate of 10%.