Authorization enables Silver Bow Mining to advance underground development, bulk sampling, and expanded surface drilling at its flagship Critical Minerals project in the Butte Mining District CEO: Rainbow Block holds "...the potential to provide a long-term supply from one of the largest and highest-grade underground silver-zinc deposits in the country, including the extraction and recovery of up to 11 U.S.-designated Critical Minerals" Butte, Montana--(Newsfile Corp. - May 26, 2026) - Silver Bow Mining Corp. (NYSE American: SBMT) ("Silver Bow Mining" or the "Company") announced today that the Montana Department of Environmental Quality ("MT DEQ") issued Silver Bow Mining an Authorization to Proceed ("AtP") for Amendment 2 ("AMD2") to Exploration License No. 00857 at the Company's flagship Rainbow Block project in Butte, Montana. Silver Bow Mining is fully authorized to conduct all surface and underground exploration activities outlined in its approved Plan of Operations. MT DEQ dated the AtP effective May 18, 2026, following the Company's satisfaction of all regulatory conditions, including the posting of a $2,188,039 surety bond for anticipated reclamation costs and MT DEQ's finalization of a Final Environmental Assessment ("Final EA") on May 8, 2026. AMD2 expands the scope of authorized exploration at the Rainbow Block, allowing both surface and underground work to further define and improve geological understanding of the deposit. "Receipt of the Authorization to Proceed marks an important milestone for Silver Bow Mining," said Travis Naugle, Chairman and Chief Executive Officer. "We have completed a thorough environmental review process, satisfied regulatory requirements, and we are now cleared to advance the next phase of exploration at the Rainbow Block. This approval authorizes development of the Rainbow Decline, expanded surface drilling, and bulk sampling activities that are expected to provide geological, engineering, and metallurgical data to support ongoing project evaluation. We intend to advance the program in accordance with our operational plans." Surface drilling at the Rainbow Block is already underway as announced in the Company's news release dated May 4, 2026 . MT DEQ authorized Amendment 1 ("AMD1") to Exploration License No. 00857 on October 4, 2021, and the Company has been drilling at the Missoula and Badger sites under that authorization. AMD2 adds seven new surface drill pad locations with significantly greater depth and footage and authorizes development of the Rainbow Decline which consists of a new portal and approximately 6,000 feet of underground development connecting to the existing Lexington Tunnel level. "The Rainbow Block holds the potential to provide a long-term supply from one of the largest and highest-grade underground silver-zinc deposits in the country, including the potential for extraction and recovery of up to 11 U.S. designated Critical Minerals. That is an extraordinary proposition spanning a broad spectrum of key inputs underpinning critical defense and civilian 21st century technology applications," continued Mr. Naugle. "We are excited to drive this work forward and help deliver the domestic Critical Minerals supply that America's national security and industrial future urgently demands." Highlights of Authorized AMD2 Activities Rainbow Decline - Underground Development: Construct one new portal with an opening of 16 feet by 15 feet and develop approximately 6,000 feet of underground workings connecting to the existing Lexington Mine shaft at the 400-foot level. Surface Drilling: Construct up to seven new drill pads and drill up to 53 surface core holes totaling approximately 102,000 feet, with individual holes reaching depths of up to 7,000 feet. Underground Drilling: Conduct underground drilling from within the Rainbow Decline to support mineral resource definition. Bulk Sampling: Stockpile up to 10,000 tons of mineralized material for bulk metallurgical testing. Development Rock: Excavate and stockpile up to 150,000 cubic yards of development rock in five surface stockpiles. Project Area: Disturb up to approximately 11.95 acres, all on previously disturbed private land in Walkerville and Butte, Montana. Timeline: Complete all exploration activities by December 31, 2029, with reclamation completed no later than December 31, 2031. Bond Posted: Surety bond of $2,188,039 posted with and accepted by MT DEQ, satisfying the reclamation bond requirement under Section 82-4-332(3), Montana Code Annotated. Building on Recent Operational Progress The AtP follows a series of significant milestones at Silver Bow Mining. On April 30, 2026, the Company completed its initial public offering on the NYSE American , with common shares trading under the symbol SBMT. On May 4, 2026, the Company announced the commencement of surface drilling at the Rainbow Block under AMD1 , a program expected to include approximately 25,000 feet of drilling. On May 12, 2026, the Company anno
