World Library  
Flag as Inappropriate
Email this Article

Cliff mine

Article Id: WHEBN0023492567
Reproduction Date:

Title: Cliff mine  
Author: World Heritage Encyclopedia
Language: English
Subject:
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Cliff mine

Native copper specimen from the Cliff mine. Size 2.4 x 1.3 x 1.3 cm.
A large native silver specimen from the Cliff mine, 5.5 x 3.7 x 2.8 cm.

The Cliff mine was the first successful copper mine in the Copper Country of the state of Michigan in the United States. The mine is at the now-abandoned town of Clifton 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 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. 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 was also recovered; approximately 41,000 ounces total silver was reported recovered in the years 1846-1852 and 1858-1871.[1]

The Pittsburgh and Boston Copper Harbor Mining Company 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.[2]

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.[3]

See also

References

  1. ^ B.S. Butler and W.S. Burbank, (1929) The Copper Deposits of Michigan, US Geological Survey, Professional Paper 144, p.83.
  2. ^ B.S. Butler and W.S. Burbank, (1929) The Copper Deposits of Michigan, US Geological Survey, Professional Paper 144, p.67, 83.
  3. ^ Horace J. Stevens, (1908) The Copper Handbook, v.8, Houghton, Michigan: Horace Stevens, p.1301.

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.

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.