El Porvenir operates a mechanised overhand cut and fill underground mine and a conventional 6.5 kt/d concentrator (operated currently at 5.9kt/d) that produces zinc, lead and copper concentrates. The deepest sector of the mine is 1,250m deep. Because of this the deepest stopes must continue using the overhand cut and fill with 4 meters lifts to deal with high stress concentrations. In July 2018 the concentrator was being expanded from 6.5kt/d ore to 7.5kt/d ore. This was expected for 2019. We have included this expansion in our analysis.