Cliff mine

[citation needed] The Cliff mined a fissure vein of native copper in Precambrian conglomerate and basalt beds.

The vein was nearly vertical, dipping steeply to the east, and running north–south, nearly perpendicular to the strike of the enclosing beds.

The productive part of the vein was below the Greenstone flow, which forms the cliff from which the mine took its name.

[3] According to legend, the great Cliff was discovered when an unnamed prospector fell down the face of a greenstone bluff and painfully injured his behind on a projecting piece of solid copper.

[4] In The Gilded Age (S01E04; 2023)[5] the character Mrs. Chamberlain states that her ‘lucky’ husband was there when they sank the Cliff copper mine in the Keweenaw County, which was the source of their ‘new money’.