This old refiner started back in 1973 in Iowa, but settled in South Dakota in 1976 where they ran a smelting operation near the owners farm in Hudson, South Dakota. The following link is from a 1988 court case that details the inner workings of the business with some related entities. It appears the entities became hostile toward one another in the late 80s with Tri-State being awarded damages. Very interesting link. https://law.justia.com/cases/south-dakota/supreme-court/1988/15953-1.html
Tri-State did pressed and poured bars in sizes of 1, 5, and 10+ oz. Here are a few from my collection and Brian Rs collection.
Vintage Silver Bars 