Bolivar Sierra is an underground operation utilising room and pillar and sub level stoping methods. The Piedras Verdes processing plant is located 5km from the mine and adopts conventional flotation. Initially it had a processing capacity of 1 000t/d but in September 2013 a new circuit was installed increasing the capacity to 2 000t/d. Towards the end of 2015 Sierra Metals was producing at a rate of approximately 2 500t/d and in 2016 throughput was averaged 2 800t/d through 2016. The Company are now taking the necessary steps to increase the daily throughput further to 3 000t/d and the objective is to reach 3 500t/d by year end 2017.