Discussion & Detection
As we have been unable to find any genuine examples of Montana Miners Silver Corp bars, this appears to be a fantasy piece modeled after Pan American and Northwest Territorial Mint bars. A trademark was registered in 2013 for "Sierra Nevada Territorial Mint" by a company that produces mining equipment, which may or may not be related to the production of this bar. We could not find any other products bearing the "Sierra Nevada Territorial Mint" name.
There are no genuine Montana Miners bars to compare this to, but this bar does have sharper corners and came packaged in a chunky plastic capsule, two common traits of other early counterfeit silver bars. The Precious Metal Verifier and Precious Metal Verifier PRO both easily identify this bar as fake.