LAUSR

Abstract The definition of caving economic limits is one of the initial steps in the planning and design of caving projects. This paper proposes a binary optimization framework to integrate the caving envelope and production schedule that maximizes the net present value of the project under technical constraints that model the caving operation mechanics. The constraints considered in the framework are mining capacities, draw rates, maximum and minimum column heights, horizontal and vertical precedences, undercut development rates and the maximum relative adjacent height of draw between columns. An early-start algorithm is used to reduce the number of decision variables and a sliding-time heuristic is applied to significantly reduce the computing time. The framework is implemented in a MATLAB environment with CPLEX as the optimization engine. A case study is presented for the section of a copper deposit, where different horizons were evaluated to select the optimal undercut level and define the caving envelope and initial production schedule. Results were obtained in under 20 min, which allows the method to be efficiently used to evaluate multiple scenarios.