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

Ref.: Rocks & Min.: 58:112; 63:494; 65:240-243, U.S.G.S PP 144, "Red Gold & Tarnished Silver", by CCRMC.

An underground copper mine consisting of two shafts and four adits located approx. 40 miles SW of Houghton, MI. The Caledonia Mining Co. was organized in 1863 after purchasing the Nebraska and Kansas Mining Co. properties. Operations continued until 1871, when Caledonia and the Flinsteel Copper Co. merged together. In 1872, the mine closed having produced approx. 903,000 lbs. of refined copper. From 1873 to 1881, the mine was tributed and another 330,000 lbs. of copper was produced, including one mass weighing 40 tons. The mine was dormant until 1937, when Calumet & Hecla reopened the #4 adit for exploration, but stopped the project due to World War 2. In 1950, C&H returned to continue exploration, drifting, and stoping. Between 1951 and 1958, C&H removed approx. 5.5 million lbs. of refined copper from the #4 adit. In 1985, Red Metal Explorations aquired the Caledonia Mine and continues exploration of the property today. The mine is the centerpiece for a week long series of mineral collecting field trips in August put on by local organizations. The mine is exceptional for copper, silver, and datolite, as well as a range of microminerals.