In this paper we introduce a simple ant based algorithm for solving a copper mine planning problem. In the last 10 years this realworld problem has been tackled using linear integer programming and constraint programming. However, because it is a large scale problem, the model must be simplified by relaxing many constraints in order to obtain a near-optimal solution in a reasonable time. We now present an algorithm which takes into account most of the problem constraints and it is able to find better near-optimal feasible solutions than the approach that has been used until now.