The Cliff mine was the first successful copper mine in the

Copper Country The Copper Country is an area in the Upper Peninsula of Michigan in the United States, including Keweenaw County, Michigan, Houghton, Baraga and Ontonagon counties as well as part of Marquette County. The area is so named as copper minin ...

of the state of

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

. The mine is at the now-abandoned town of

Clifton Clifton may refer to: People *Clifton (surname) *Clifton (given name) Places Australia *Clifton, Queensland, a town **Shire of Clifton * Clifton, New South Wales, a suburb of Wollongong * Clifton, Western Australia Canada * Clifton, Nova Scot ...

in Keweenaw County. Mining began in 1845, and the Cliff was the most productive copper mine in the United States from 1845 through 1854. Large-scale mining stopped in 1878. The Cliff mined a fissure vein of

native copper Native copper is an uncombined form of copper that occurs as a natural mineral. Copper is one of the few metallic elements to occur in native form, although it most commonly occurs in oxidized states and mixed with other elements. Native copp ...

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...

conglomerate and

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of a ...

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. The mine started by mining only high-grade ore; in 1848, the average grade mined was 26% copper. The average ore grade mined declined over time, and by 1869 was 3% copper, comparable to other copper mines of the time. Some

native silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

was also recovered; approximately 41,000 ounces total silver was reported recovered in the years 1846-1852 and 1858-1871. The

Pittsburgh and Boston Copper Harbor Mining Company Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylva ...

and its successor the Pittsburgh and Boston Mining Company operated the Cliff mine from 1845 to 1870, then sold the property to the Cliff Copper Company in 1871. The Cliff Copper Company operated the mine from 1872 to 1878. The combined dividends paid by the companies was $2.5 million. The mine was then leased to tributers, who continued minor copper production through 1887. Total production was 38.2 million pounds of refined copper. The Tamarack Mining Company bought the Cliff property and did extensive subsurface exploration from 1903 to 1908, but did not find any new ore bodies worth mining.

Origins

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.

References

External links

* Mindat.org
''Cliff mine, Phoenix, Keweenaw Co., Michigan, USA''
accessed 6 July 2009. * Cliff Mine Archaeology Survey, official website and blog
''CliffMine.wordpress.com''
accessed 18 April 2010. {{coord, 47, 22, 22.77, N, 88, 18, 49.15, W, region:US, display=title Copper mines in Michigan Silver mines in the United States Buildings and structures in Keweenaw County, Michigan Underground mines in the United States

Origins

See also

References

External links