Copper chisel chip - Cliff mine, Michigan

Description: A native copper chisel chip from the Cliff Mine, Michigan. Here we have a native copper chisel chip cut by Cornish miners - pre-civil war most likely, from the multi-ton native copper masses in the renowned Cliff Mine, Michigan. Each "wrinkle" represents a 4 to 6-pound sledgehammer blow using a cape chisel, a cold chisel with a long taper on the top and bottom of the cutting end, and a narrow edge is used for cutting keyways and similar flat grooves. (Note the above photograph of a typical cape chisel). The Cliff Mine was the first successful copper mine in the Copper Country 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. 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, (Tributers generally work in gangs and have a limited portion of a lode set them, called a tribute pitch, beyond which they are not permitted to work, and for which they receive a certain portion of the ore, or so much per pound, as agreed upon, of the value of what they raise.) who continued minor copper production through 1887. Total production was 38.2 million pounds (17327 metric tons) 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. Dimensions are 3x2.5x1.5cm - 1¼x1x½in. Please note the centimeter cube and inch bar for scale. Weight in grams and ounces: 31.6g - 1.12oz. From the Cliff mine, Michigan. The previous collection this specimen was in is #136, Dr. Allan Johnson. #136 is the museum's Collection Sale number previously offered in the museum shop. >>> We do COMBINED SHIPPING for multiple items. To request an invoice from us that combines shipping ALWAYS, click the Add to cart button on eBay to add items until you are done. DO NOT PROCEED to checkout; instead, click the Request Total from Seller button. <<< === There is an instructional video on how to request combined shipping is here https://www.youtube.com/watch?v=FvDe7Fg7R4Q === >>>> We Buy Collections <<<< DISCLAIMER: Every reasonable effort was made to identify the mineral species noted in each specimen accurately. The occasional label from previous collection(s) may misidentify some species, and the current title and description here reflect the latest mineral species identification. Buyers should also be aware of what type of lighting to view the specimens under. This can result in perceived differences of color and contrast due to color and contrast shifting under various kinds of lights available.All photographs were taken with a Nikon D5300 digital camera with a Nikon DX AF-S 18-55mm lens attached with a UV filter. Lighting was done with a pair of OSRAM 8.5 watt LED A19 5000K 800 lumens bulbs in brushed aluminum reflectors. The photographs were processed on a color-calibrated flat panel monitor. Do note the Imperial measurement conversion is the nearest equivalent to the listed metric measurement. --- All photographs appearing on this listing or any other Franklin Mineral Museum listing are the property of the Franklin Mineral Museum. Photographs can be used strictly for personal use only. Otherwise, the photographs posted here are protected by U.S. Copyright Laws. They are not to be downloaded or reproduced for public use or distribution in any way without the written permission of the Franklin Mineral Museum. ---

Price: 35 USD

Location: Franklin, New Jersey

End Time: 2024-12-17T05:30:14.000Z

Shipping Cost: 8 USD