Portsmouth Mine, self-contained drilling unit drilling holes
A drilling unit operates at the Portsmouth Mine. The Portsmouth Mine is an open pit iron mine in the Cuyuna Range, Minnesota. The Portsmouth Mine opened in 1919 and was operated by several companies before being operated as part of the Portsmouth Group of mines by M. A. Hanna Company starting in 1945. The M. A. Hanna Company was one of the large mining companies that moved into the iron ranges in the early 1900s, consolidating smaller properties and engaging in exploration for other economic deposits. The Company was dissolved in 1965, then resurrected in 1985.