AUSTIN, TX / ACCESS Newswire / December 8, 2025 / American Antimony Corporation (OTCID:XTPT), operating as Xtra Energy Corporation, a U.S.-based mineral development company focused on domestic antimony resources, and Silver Opportunity Partners LLC, a subsidiary of Sunshine Silver Mining & Refining Company (SSMRC), are pleased to announce they have entered into a formal Metallurgical Testing Agreement (MTA) to evaluate antimony-bearing material from American Antimony's American Antimony Project, located in ...