This final image of the mine shows the face of the blocked tunnel where a water reservoir was located. The open pipes and valves present in the wall face indicate the water is no longer stored here.
The description states:
ARCADIAN COPPER MINE TOURS — End of tour at Water Reservoir. Original Arcadian Mine established 1864 in Ripley, Michigan, on M26 one mile from Hancock, Michigan. Believe it or not it is the only underground Copper Mine in the world open to the public.
–The term M26 refers to the Michigan state highway that was constructed near the mine. The mine long predates the highway. The card is dated 1955.