The Informe Tecnico Sustentatorio (ITS) permit, issued by the Peruvian Ministry of Environment through its Agency SENACE, is the second to the last step needed for the jump in rates.
The company plans to increase the facility's permitted throughput to 3,600 tonnes per day, a 20% increase over current rates - which will in turn permit the miner to maintain its annual production guidance.
"I am delighted with the receipt of the ITS permit; the company may now submit the required documentation for an Informe Tecnico Minero (ITM) permit, which is the final step in the process," CEO Luis Marchese said.
"The company expects to receive the ITM permit in the second quarter of 2021."
Sierra is also continuing its prefeasibility study work at Yauricocha, which is focused on the miner's goal of increasing throughput to 5,500t/d starting in 2024.
Canadian-based Sierra Metals owns the Yauricocha mine as well as the Bolivar and Cusi mines in Mexico.