Mass Mine, Mass Consolidated Mine, Mass City, Ontonagon Co., Michigan, USA

Ref.: Rocks & Min.: 58:112 & 65:240, U.S.G.S. PP 144.

An underground copper mine consisting of three shafts adjacent to Mass City, MI. The Mass Mining Co. was organized in 1856 and worked sporadically until 1888, when the mine operations ceased for good. The mine was merged into the Mass Consolidated Mining Co. in 1899. A wide range of minerals can be found at the original Mass Mine site, including copper, silver, and datolite.