Elizabeth Mine
Encyclopedia
The Elizabeth Mine was a copper mine located in Orange County, Vermont, some miles south of the town of Strafford
Strafford, Vermont
Strafford is a town in Orange County, Vermont, United States. The population was 1,045 at the 2000 census. The town of Strafford was created on August 12, 1761 by way of a royal charter which King George III of England issued to Governor Benning Wentworth of New Hampshire...

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The ore deposite was discovered in 1793, but mining did not start until 1809. Open pit mining and from 1886 underground mining was conducted. The mine produced up to 8,500,000 lbs. of copper (1954) and was closed in 1957.

Due to acid mine drainage
Acid mine drainage
Acid mine drainage , or acid rock drainage , refers to the outflow of acidic water from metal mines or coal mines. However, other areas where the earth has been disturbed may also contribute acid rock drainage to the environment...

 the west branch of the Ompompanoosuc River
Ompompanoosuc River
The Ompompanoosuc River is a river, about 25 mi long, in eastern Vermont in the United States. It is a tributary of the Connecticut River, which flows to Long Island Sound...

 was polluted. Since 2000 the Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

 (EPA) and the Vermont Agency of Natural Resources have been developing a plan to clean up the area.

Geology

The ore deposits at the Elizabeth Mine are hosted in the strongly deformed Devonian Guile Mountain Formation (a grey to dark grey mica schist
Schist
The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is...

). Ore deposits are localized in zones of high permeability associated with deformation that occurred during the Acadian Orogeny
Acadian orogeny
The Taconic, Acadian and Alleghenian orogenies are the three tectonic phases responsible for the formation of the present Appalachian Mountains. The Acadian orogeny is a middle Paleozoic mountain building episode dating back 325-400 million years which should not be regarded as a single event but...

. The ore body is principally a massive sulfide deposit consisting primarily of pyrrhotite
Pyrrhotite
Pyrrhotite is an unusual iron sulfide mineral with a variable iron content: FeS . The FeS endmember is known as troilite. Pyrrhotite is also called magnetic pyrite because the color is similar to pyrite and it is weakly magnetic...

 and chalcopyrite
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.On exposure to air, chalcopyrite...

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External links

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