Sierra Metals Confirms High Grade Mineralized Extensions to the Bolivar West Zone, at the Bolivar Mine, Mexico https://www.sierrametals.com/investors/news-releases/press-release-details/2019/Sierra-Metals-Confirms-High-Grade-Mineralized-Extensions-to-the-Bolivar-West-Zone-at-the-Bolivar-Mine-Mexico/default.aspx 04/03/2019