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Environmental Behavior of Mineral Deposits

Acid Mine Drainage, Elizabeth Mine and Vermont Copper Belt, Vermont

Copper mining has been historically important to the economy of Vermont, but drainage from abandoned mines continues to negatively impact the environment. The USGS has been cooperating with a local citizens' group, the Elizabeth Mine Study Group, to evaluate acid mine drainage around the Elizabeth mine near South Strafford, which will potentially serve as the basis for future reclamation of the site.  Research efforts have also been coordinated with the Vermont Agency of Natural Resources and the U.S. Environmental Protection Agency.  Mining began at Elizabeth in the late 18th century and continued intermittently until 1958. Similar, but smaller mines were also in operation north of South Strafford near West Fairlee and Corinth. 

At the time of this study, waters draining the Elizabeth mine workings and waste piles are acidic and laden with toxic heavy metals. USGS studies have focused on understanding the chemical and hydrological processes by which the rocks and waste piles weather to produce acid mine drainage. Cooperative efforts with the Elizabeth Mine Study Group have concentrated on assessing toxic heavy metal loads from the upper part of the watershed. To date, the USGS has helped train the group in water sampling protocols, and has provided analytical support and assistance in data interpretation.  Additional USGS efforts have also concentrated on defining the complexity of mine drainage environments at the site.  Reconnaissance studies are also underway at other mines in the Vermont Copper Belt.

	Mine waste piles from the oldest phase of historic mining at the Elizabeth copper mine, which closed in 1958.
	Map of Elizabeth Mine Site.  Studies have defined at least four distinct chemical environments of drainage at the site including water in mine workings, oxygenated surface waters draining the Copperas Brook watershed, anoxic groundwaters seeping out of the base of the large tailings pile, and regional ground and surface waters not impacted by mine drainage or wastes.  Metal and acid loading to the West Branch of the Ompompanoosuc River from the site is dominated by Copperas Brook and an utility shaft that drains the mine workings on the south bank of the river.
	pH vs. iron.  The effect of the presence or absence of dissolved oxygen in waters at the site is clearly reflected in the concentrations of dissolved iron as a function of pH.
	pH vs.copper.  The graph shows the increased solubility of copper with more acidic pH.  Also shown is the Environmental Protection Agency's acute toxicity limit for aquatic ecosystems.
	pH vs. zinc.  The graph shows the increased solubility of zinc with more acidic pH.  Also shown is the Environmental Protection Agency's acute toxicity limit for aquatic ecosystems.

Products

Hammarstrom, J.M., Jackson, J.C., Barden, R., and Seal, R.R., 1999,

Characterization of Mine Waste at the Abandoned Elizabeth Copper Mine, Vermont [abs.]: Geological Society of America, Abstracts with Programs (NE), v. 31, p. A-20.

 

Krishnaswamy, R., and Seal, R.R., II, 1998,

Ecological and carbon isotope data for acidophilic algae from abandoned mine sites in Vermont and Virginia [abs.]: Geological Society of America, Abstracts with Programs, v. 30, p. A129.

Seal, R.R., II, Haffner, D.P., Meier, A.L., Krishnaswamy, R., and Hammarstrom, J.M., 1999,

Geochemistry of acid mine drainage from the abandoned Elizabeth copper mine, South Strafford, Vermont [abs.]: Geological Society of America, Abstracts with Programs (NE), v. 31, p. A-66.

Collaborators

In addition to the Elizabeth Mine Study Group, USGS efforts are being coordinated with a variety of state and federal agencies including Vermont Department of Environmental Conservation, U.S. Department of Energy, U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, and Dartmouth College.