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.